]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_exec.c
xnu-2422.110.17.tar.gz
[apple/xnu.git] / bsd / kern / kern_exec.c
index 1db47973a1063ca3a72e037f642a77b746d9844e..0fb4a347a1e38dd9bfead399dd7235a182e0f8ca 100644 (file)
@@ -1,23 +1,29 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2011 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
 /*
  *
  *     from: @(#)kern_exec.c   8.1 (Berkeley) 6/10/93
  */
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections.  This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
+ */
 #include <machine/reg.h>
+#include <machine/cpu_capabilities.h>
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/filedesc.h>
 #include <sys/kernel.h>
-#include <sys/proc.h>
+#include <sys/proc_internal.h>
+#include <sys/kauth.h>
 #include <sys/user.h>
-#include <sys/buf.h>
 #include <sys/socketvar.h>
 #include <sys/malloc.h>
 #include <sys/namei.h>
-#include <sys/mount.h>
-#include <sys/vnode.h>         
-#include <sys/file.h>
+#include <sys/mount_internal.h>
+#include <sys/vnode_internal.h>                
+#include <sys/file_internal.h>
 #include <sys/stat.h>
-#include <sys/uio.h>
+#include <sys/uio_internal.h>
 #include <sys/acct.h>
 #include <sys/exec.h>
 #include <sys/kdebug.h>
 #include <sys/signal.h>
+#include <sys/aio_kern.h>
+#include <sys/sysproto.h>
+#if SYSV_SHM
+#include <sys/shm_internal.h>          /* shmexec() */
+#endif
+#include <sys/ubc_internal.h>          /* ubc_map() */
+#include <sys/spawn.h>
+#include <sys/spawn_internal.h>
+#include <sys/process_policy.h>
+#include <sys/codesign.h>
+#include <crypto/sha1.h>
 
+#include <libkern/libkern.h>
+
+#include <security/audit/audit.h>
+
+#include <ipc/ipc_types.h>
+
+#include <mach/mach_types.h>
+#include <mach/port.h>
+#include <mach/task.h>
+#include <mach/task_access.h>
+#include <mach/thread_act.h>
+#include <mach/vm_map.h>
+#include <mach/mach_vm.h>
 #include <mach/vm_param.h>
 
+#include <kern/sched_prim.h> /* thread_wakeup() */
+#include <kern/affinity.h>
+#include <kern/assert.h>
+#include <kern/task.h>
+
+#if CONFIG_MACF
+#include <security/mac.h>
+#include <security/mac_mach_internal.h>
+#endif
+
 #include <vm/vm_map.h>
 #include <vm/vm_kern.h>
+#include <vm/vm_protos.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_fault.h>
+#include <vm/vm_pageout.h>
+
+#include <kdp/kdp_dyld.h>
+
+#include <machine/pal_routines.h>
+
+#include <pexpert/pexpert.h>
+
+#if CONFIG_MEMORYSTATUS
+#include <sys/kern_memorystatus.h>
+#endif
+
+#if CONFIG_DTRACE
+/* Do not include dtrace.h, it redefines kmem_[alloc/free] */
+extern void (*dtrace_fasttrap_exec_ptr)(proc_t);
+extern void (*dtrace_helpers_cleanup)(proc_t);
+extern void dtrace_lazy_dofs_destroy(proc_t);
+
+#include <sys/dtrace_ptss.h>
+#endif
+
+/* support for child creation in exec after vfork */
+thread_t fork_create_child(task_t parent_task, proc_t child_proc, int inherit_memory, int is64bit);
+void vfork_exit(proc_t p, int rv);
+int setsigvec(proc_t, thread_t, int, struct __kern_sigaction *, boolean_t in_sigstart);
+extern void proc_apply_task_networkbg_internal(proc_t, thread_t);
+
+/*
+ * Mach things for which prototypes are unavailable from Mach headers
+ */
+void           ipc_task_reset(
+                       task_t          task);
+void           ipc_thread_reset(
+                       thread_t        thread);
+kern_return_t ipc_object_copyin(
+       ipc_space_t             space,
+       mach_port_name_t        name,
+       mach_msg_type_name_t    msgt_name,
+       ipc_object_t            *objectp);
+void ipc_port_release_send(ipc_port_t);
+
+extern struct savearea *get_user_regs(thread_t);
+
 
 #include <kern/thread.h>
 #include <kern/task.h>
-
 #include <kern/ast.h>
 #include <kern/mach_loader.h>
+#include <kern/mach_fat.h>
 #include <mach-o/fat.h>
 #include <mach-o/loader.h>
 #include <machine/vmparam.h>
+#include <sys/imgact.h>
+
+#include <sys/sdt.h>
+
+
+/*
+ * EAI_ITERLIMIT       The maximum number of times to iterate an image
+ *                     activator in exec_activate_image() before treating
+ *                     it as malformed/corrupt.
+ */
+#define EAI_ITERLIMIT          10
+
+/*
+ * For #! interpreter parsing
+ */
+#define IS_WHITESPACE(ch) ((ch == ' ') || (ch == '\t'))
+#define IS_EOL(ch) ((ch == '#') || (ch == '\n'))
 
 extern vm_map_t bsd_pageable_map;
+extern const struct fileops vnops;
 
 #define        ROUND_PTR(type, addr)   \
-       (type *)( ( (unsigned)(addr) + 16 - 1) \
+       (type *)( ( (uintptr_t)(addr) + 16 - 1) \
                  & ~(16 - 1) )
 
+struct image_params;   /* Forward */
+static int exec_activate_image(struct image_params *imgp);
+static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp);
 static int load_return_to_errno(load_return_t lrtn);
-int execve(struct proc *p, struct execve_args *uap, register_t *retval);
+static int execargs_alloc(struct image_params *imgp);
+static int execargs_free(struct image_params *imgp);
+static int exec_check_permissions(struct image_params *imgp);
+static int exec_extract_strings(struct image_params *imgp);
+static int exec_add_apple_strings(struct image_params *imgp);
+static int exec_handle_sugid(struct image_params *imgp);
+static int sugid_scripts = 0;
+SYSCTL_INT (_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW | CTLFLAG_LOCKED, &sugid_scripts, 0, "");
+static kern_return_t create_unix_stack(vm_map_t map, load_result_t* load_result, proc_t p);
+static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size);
+static void exec_resettextvp(proc_t, struct image_params *);
+static int check_for_signature(proc_t, struct image_params *);
+static void exec_prefault_data(proc_t, struct image_params *, load_result_t *);
+static errno_t exec_handle_port_actions(struct image_params *imgp, short psa_flags, int * need_portwatch, ipc_port_t * portwatch);
+static errno_t exec_handle_spawnattr_apptype(proc_t p, int psa_apptype);
 
-int
-execv(p, args, retval)
-       struct proc *p;
-       void *args;
-       int *retval;
+/*
+ * exec_add_user_string
+ *
+ * Add the requested string to the string space area.
+ *
+ * Parameters; struct image_params *           image parameter block
+ *             user_addr_t                     string to add to strings area
+ *             int                             segment from which string comes
+ *             boolean_t                       TRUE if string contributes to NCARGS
+ *
+ * Returns:    0                       Success
+ *             !0                      Failure errno from copyinstr()
+ *
+ * Implicit returns:
+ *             (imgp->ip_strendp)      updated location of next add, if any
+ *             (imgp->ip_strspace)     updated byte count of space remaining
+ *             (imgp->ip_argspace) updated byte count of space in NCARGS
+ */
+static int
+exec_add_user_string(struct image_params *imgp, user_addr_t str, int seg, boolean_t is_ncargs)
 {
-       ((struct execve_args *)args)->envp = NULL;
-       return (execve(p, args, retval));
+       int error = 0;
+       
+       do {
+               size_t len = 0;
+               int space;
+               
+               if (is_ncargs)
+                       space = imgp->ip_argspace; /* by definition smaller than ip_strspace */
+               else
+                       space = imgp->ip_strspace;
+               
+               if (space <= 0) {
+                       error = E2BIG;
+                       break;
+               }
+               
+               if (!UIO_SEG_IS_USER_SPACE(seg)) {
+                       char *kstr = CAST_DOWN(char *,str);     /* SAFE */
+                       error = copystr(kstr, imgp->ip_strendp, space, &len);
+               } else  {
+                       error = copyinstr(str, imgp->ip_strendp, space, &len);
+               }
+
+               imgp->ip_strendp += len;
+               imgp->ip_strspace -= len;
+               if (is_ncargs)
+                       imgp->ip_argspace -= len;
+               
+       } while (error == ENAMETOOLONG);
+       
+       return error;
 }
 
-/* ARGSUSED */
-int
-execve(p, uap, retval)
-       register struct proc *p;
-       register struct execve_args *uap;
-       register_t *retval;
-{
-       register struct ucred *cred = p->p_ucred;
-       register struct filedesc *fdp = p->p_fd;
-       register nc;
-       register char *cp;
-       int na, ne, ucp, ap, cc;
-       unsigned len;
-       int indir;
-       char *sharg;
-       char *execnamep;
-       struct vnode *vp;
-       struct vattr vattr;
-       struct vattr origvattr;
-       vm_offset_t execargs;
-       struct nameidata nd;
-       struct ps_strings ps;
-#define        SHSIZE  512
-       char cfarg[SHSIZE];
-       boolean_t               is_fat;
-       kern_return_t           ret;
-       struct mach_header      *mach_header;
-       struct fat_header       *fat_header;
-       struct fat_arch         fat_arch;
-       load_return_t           lret;
-       load_result_t           load_result;
-       struct uthread          *uthread;
-       int i;
-       union {
-               /* #! and name of interpreter */
-               char                    ex_shell[SHSIZE];
-               /* Mach-O executable */
-               struct mach_header      mach_header;
-               /* Fat executable */
-               struct fat_header       fat_header;
-               char    pad[512];
-       } exdata;
-       int resid, error;
-       char *savedpath;
-       int savedpathlen = 0;
-       vm_offset_t *execargsp;
-       char *cpnospace;
-       task_t tsk;
-       int numthreads;
+/*
+ * exec_save_path
+ *
+ * To support new app package launching for Mac OS X, the dyld needs the
+ * first argument to execve() stored on the user stack.
+ *
+ * Save the executable path name at the bottom of the strings area and set
+ * the argument vector pointer to the location following that to indicate
+ * the start of the argument and environment tuples, setting the remaining
+ * string space count to the size of the string area minus the path length.
+ *
+ * Parameters; struct image_params *           image parameter block
+ *             char *                          path used to invoke program
+ *             int                             segment from which path comes
+ *
+ * Returns:    int                     0       Success
+ *             EFAULT                          Bad address
+ *     copy[in]str:EFAULT                      Bad address
+ *     copy[in]str:ENAMETOOLONG                Filename too long
+ *
+ * Implicit returns:
+ *             (imgp->ip_strings)              saved path
+ *             (imgp->ip_strspace)             space remaining in ip_strings
+ *             (imgp->ip_strendp)              start of remaining copy area
+ *             (imgp->ip_argspace)             space remaining of NCARGS
+ *             (imgp->ip_applec)               Initial applev[0]
+ *
+ * Note:       We have to do this before the initial namei() since in the
+ *             path contains symbolic links, namei() will overwrite the
+ *             original path buffer contents.  If the last symbolic link
+ *             resolved was a relative pathname, we would lose the original
+ *             "path", which could be an absolute pathname. This might be
+ *             unacceptable for dyld.
+ */
+static int
+exec_save_path(struct image_params *imgp, user_addr_t path, int seg)
+{
+       int error;
+       size_t  len;
+       char *kpath;
 
-       tsk = current_task();
+       len = MIN(MAXPATHLEN, imgp->ip_strspace);
 
+       switch(seg) {
+       case UIO_USERSPACE32:
+       case UIO_USERSPACE64:   /* Same for copyin()... */
+               error = copyinstr(path, imgp->ip_strings, len, &len);
+               break;
+       case UIO_SYSSPACE:
+               kpath = CAST_DOWN(char *,path); /* SAFE */
+               error = copystr(kpath, imgp->ip_strings, len, &len);
+               break;
+       default:
+               error = EFAULT;
+               break;
+       }
 
-       if(tsk != kernel_task) { 
-               numthreads = get_task_numacts(tsk);
-               if (numthreads <= 0 )
-                       return(EINVAL);
-               if (numthreads > 1) {
-                       return(EOPNOTSUPP);
-               }
+       if (!error) {
+               imgp->ip_strendp += len;
+               imgp->ip_strspace -= len;
        }
 
-       ret = kmem_alloc_pageable(bsd_pageable_map, &execargs, NCARGS);
-       if (ret != KERN_SUCCESS)
-               return(ENOMEM);
+       return(error);
+}
+
+/*
+ * exec_reset_save_path
+ *
+ * If we detect a shell script, we need to reset the string area
+ * state so that the interpreter can be saved onto the stack.
+
+ * Parameters; struct image_params *           image parameter block
+ *
+ * Returns:    int                     0       Success
+ *
+ * Implicit returns:
+ *             (imgp->ip_strings)              saved path
+ *             (imgp->ip_strspace)             space remaining in ip_strings
+ *             (imgp->ip_strendp)              start of remaining copy area
+ *             (imgp->ip_argspace)             space remaining of NCARGS
+ *
+ */
+static int
+exec_reset_save_path(struct image_params *imgp)
+{
+       imgp->ip_strendp = imgp->ip_strings;
+       imgp->ip_argspace = NCARGS;
+       imgp->ip_strspace = ( NCARGS + PAGE_SIZE );
 
-       uthread = get_bsdthread_info(current_act());
+       return (0);
+}
 
-       savedpath = execargs;
+/*
+ * exec_shell_imgact
+ *
+ * Image activator for interpreter scripts.  If the image begins with the
+ * characters "#!", then it is an interpreter script.  Verify that we are
+ * not already executing in PowerPC mode, and that the length of the script
+ * line indicating the interpreter is not in excess of the maximum allowed
+ * size.  If this is the case, then break out the arguments, if any, which
+ * are separated by white space, and copy them into the argument save area
+ * as if they were provided on the command line before all other arguments.
+ * The line ends when we encounter a comment character ('#') or newline.
+ *
+ * Parameters; struct image_params *   image parameter block
+ *
+ * Returns:    -1                      not an interpreter (keep looking)
+ *             -3                      Success: interpreter: relookup
+ *             >0                      Failure: interpreter: error number
+ *
+ * A return value other than -1 indicates subsequent image activators should
+ * not be given the opportunity to attempt to activate the image.
+ */
+static int
+exec_shell_imgact(struct image_params *imgp)
+{
+       char *vdata = imgp->ip_vdata;
+       char *ihp;
+       char *line_startp, *line_endp;
+       char *interp;
+       proc_t p;
+       struct fileproc *fp;
+       int fd;
+       int error;
 
        /*
-        * To support new app package launching for Mac OS X, the dyld
-        * needs the first argument to execve() stored on the user stack.
-        * Copyin the "path" at the begining of the "execargs" buffer
-        * allocated above.
+        * Make sure it's a shell script.  If we've already redirected
+        * from an interpreted file once, don't do it again.
         *
-        * We have to do this before namei() because in case of
-        * symbolic links, namei() would overwrite the original "path".
-        * In case the last symbolic link resolved was a relative pathname
-        * we would loose the original "path", which could be an
-        * absolute pathname. This might be unacceptable for dyld.
-        */
-       /* XXX We could optimize to avoid copyinstr in the namei() */
-       
-       error = copyinstr(uap->fname, savedpath, MAXPATHLEN, &savedpathlen);
-       if (error)
-               return (error);
-       /*
-        * copyinstr will put in savedpathlen, the count of
-        * characters (including NULL) in the path.
+        * Note: We disallow PowerPC, since the expectation is that we
+        * may run a PowerPC interpreter, but not an interpret a PowerPC 
+        * image.  This is consistent with historical behaviour.
         */
-       
-       /* Save the name aside for future use */
-       execargsp = (vm_offset_t *)((char *)(execargs) + savedpathlen);
-       
-       NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | SAVENAME,
-                                       UIO_USERSPACE, uap->fname, p);
-       if ((error = namei(&nd)))
-               goto bad1;
-       vp = nd.ni_vp;
-       VOP_LEASE(vp, p, p->p_ucred, LEASE_READ);
-
-       if ((error = VOP_GETATTR(vp, &origvattr, p->p_ucred, p)))
-               goto bad;
-
-       /* Check mount point */
-       if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
-               error = EACCES;
-               goto bad;
+       if (vdata[0] != '#' ||
+           vdata[1] != '!' ||
+           (imgp->ip_flags & IMGPF_INTERPRET) != 0) {
+               return (-1);
        }
 
-       indir = 0;
-       if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED))
-               origvattr.va_mode &= ~(VSUID | VSGID);
-               
-       *(&vattr) = *(&origvattr);
-
-again:
-       error = check_exec_access(p, vp, &vattr);
-       if (error)
-               goto bad;
+       imgp->ip_flags |= IMGPF_INTERPRET;
+       imgp->ip_interp_sugid_fd = -1;
+       imgp->ip_interp_buffer[0] = '\0';
 
-       /*
-        * Read in first few bytes of file for segment sizes, magic number:
-        *      407 = plain executable
-        *      410 = RO text
-        *      413 = demand paged RO text
-        * Also an ASCII line beginning with #! is
-        * the file name of a ``shell'' and arguments may be prepended
-        * to the argument list if given here.
-        *
-        * SHELL NAMES ARE LIMITED IN LENGTH.
-        *
-        * ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
-        * THE ASCII LINE.
+       /* Check to see if SUGID scripts are permitted.  If they aren't then
+        * clear the SUGID bits.
+        * imgp->ip_vattr is known to be valid.
         */
+       if (sugid_scripts == 0) {
+               imgp->ip_origvattr->va_mode &= ~(VSUID | VSGID);
+       }
 
-       exdata.ex_shell[0] = '\0';      /* for zero length files */
+       /* Try to find the first non-whitespace character */
+       for( ihp = &vdata[2]; ihp < &vdata[IMG_SHSIZE]; ihp++ ) {
+               if (IS_EOL(*ihp)) {
+                       /* Did not find interpreter, "#!\n" */
+                       return (ENOEXEC);
+               } else if (IS_WHITESPACE(*ihp)) {
+                       /* Whitespace, like "#!    /bin/sh\n", keep going. */
+               } else {
+                       /* Found start of interpreter */
+                       break;
+               }
+       }
 
-       error = vn_rdwr(UIO_READ, vp, (caddr_t)&exdata, sizeof (exdata), 0,
-                       UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
+       if (ihp == &vdata[IMG_SHSIZE]) {
+               /* All whitespace, like "#!           " */
+               return (ENOEXEC);
+       }
 
-       if (error)
-               goto bad;
+       line_startp = ihp;
 
-#ifndef lint
-       if (resid > sizeof(exdata) - min(sizeof(exdata.mach_header),
-                                        sizeof(exdata.fat_header))
-           && exdata.ex_shell[0] != '#') {
-               error = ENOEXEC;
-               goto bad;
-       }
-#endif /* lint */
-       mach_header = &exdata.mach_header;
-       fat_header = &exdata.fat_header;
-       if (mach_header->magic == MH_MAGIC)
-           is_fat = FALSE;
-       else if (fat_header->magic == FAT_MAGIC ||
-                fat_header->magic == FAT_CIGAM)
-           is_fat = TRUE;
-       else if (mach_header->magic == MH_CIGAM) {
-           error = EBADARCH;
-           goto bad;
-       } else {
-               if (exdata.ex_shell[0] != '#' ||
-                   exdata.ex_shell[1] != '!' ||
-                   indir) {
-                       error = ENOEXEC;
-                       goto bad;
-               }
-               cp = &exdata.ex_shell[2];               /* skip "#!" */
-               while (cp < &exdata.ex_shell[SHSIZE]) {
-                       if (*cp == '\t')
-                               *cp = ' ';
-                       else if (*cp == '\n') {
-                               *cp = '\0';
-                               break;
-                       }
-                       cp++;
-               }
-               if (*cp != '\0') {
-                       error = ENOEXEC;
-                       goto bad;
-               }
-               cp = &exdata.ex_shell[2];
-               while (*cp == ' ')
-                       cp++;
-               execnamep = cp;
-               while (*cp && *cp != ' ')
-                       cp++;
-               cfarg[0] = '\0';
-               cpnospace = cp;
-               if (*cp) {
-                       *cp++ = '\0';
-                       while (*cp == ' ')
-                               cp++;
-                       if (*cp)
-                               bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
+       /* Try to find the end of the interpreter+args string */
+       for ( ; ihp < &vdata[IMG_SHSIZE]; ihp++ ) {
+               if (IS_EOL(*ihp)) {
+                       /* Got it */
+                       break;
+               } else {
+                       /* Still part of interpreter or args */
                }
+       }
 
-               /*
-                * Support for new app package launching for Mac OS X.
-                * We are about to retry the execve() by changing the path to the
-                * interpreter name. Need to re-initialize the savedpath and
-                * savedpathlen. +1 for NULL.
-                */
-               savedpathlen = (cpnospace - execnamep + 1);
-               error = copystr(execnamep, savedpath, savedpathlen, &savedpathlen);
-               if (error)
-                       goto bad;
+       if (ihp == &vdata[IMG_SHSIZE]) {
+               /* A long line, like "#! blah blah blah" without end */
+               return (ENOEXEC);
+       }
 
-               /* Save the name aside for future use */
-               execargsp = (vm_offset_t *)((char *)(execargs) + savedpathlen);
-
-               indir = 1;
-               vput(vp);
-               nd.ni_cnd.cn_nameiop = LOOKUP;
-               nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) |
-                                               (FOLLOW | LOCKLEAF | SAVENAME);
-               nd.ni_segflg = UIO_SYSSPACE;
-               nd.ni_dirp = execnamep;
-               if ((error = namei(&nd)))
-                       goto bad1;
-               vp = nd.ni_vp;
-               VOP_LEASE(vp, p, cred, LEASE_READ);
-               if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p)))
-                       goto bad;
-               goto again;
+       /* Backtrack until we find the last non-whitespace */
+       while (IS_EOL(*ihp) || IS_WHITESPACE(*ihp)) {
+               ihp--;
        }
 
+       /* The character after the last non-whitespace is our logical end of line */
+       line_endp = ihp + 1;
+
        /*
-        * Collect arguments on "file" in swap space.
-        */
-       na = 0;
-       ne = 0;
-       nc = 0;
-       cc = 0;
-       /*
-        * Support for new app package launching for Mac OS X allocates
-        * the "path" at the begining.
-        * execargs get allocated after that
-        */
-       cp = (char *) execargsp;        /* running pointer for copy */
-       /*
-        * size of execargs less sizeof "path",
-        * a pointer to "path" and a NULL poiter
-        */
-       cc = NCARGS - savedpathlen - 2*NBPW;
-       /*
-        * Copy arguments into file in argdev area.
+        * Now we have pointers to the usable part of:
+        *
+        * "#!  /usr/bin/int first    second   third    \n"
+        *      ^ line_startp                       ^ line_endp
         */
-       if (uap->argp) for (;;) {
-               ap = NULL;
-               sharg = NULL;
-               if (indir && na == 0) {
-                       sharg = nd.ni_cnd.cn_nameptr;
-                       ap = (int)sharg;
-                       uap->argp++;            /* ignore argv[0] */
-               } else if (indir && (na == 1 && cfarg[0])) {
-                       sharg = cfarg;
-                       ap = (int)sharg;
-               } else if (indir && (na == 1 || (na == 2 && cfarg[0])))
-                       ap = (int)uap->fname;
-               else if (uap->argp) {
-                       ap = fuword((caddr_t)uap->argp);
-                       uap->argp++;
-               }
-               if (ap == NULL && uap->envp) {
-                       uap->argp = NULL;
-                       if ((ap = fuword((caddr_t)uap->envp)) != NULL)
-                               uap->envp++, ne++;
-               }
-               if (ap == NULL)
-                       break;
-               na++;
-               if (ap == -1) {
-                       error = EFAULT;
-                       break;
-               }
-               do {
-                       if (nc >= (NCARGS - savedpathlen - 2*NBPW -1)) {
-                               error = E2BIG;
-                               break;
-                       }
-                       if (sharg) {
-                               error = copystr(sharg, cp, (unsigned)cc, &len);
-                               sharg += len;
-                       } else {
-                               error = copyinstr((caddr_t)ap, cp, (unsigned)cc,
-                                   &len);
-                               ap += len;
-                       }
-                       cp += len;
-                       nc += len;
-                       cc -= len;
-               } while (error == ENAMETOOLONG);
-               if (error) {
-                       goto bad;
-               }
-       }
-       nc = (nc + NBPW-1) & ~(NBPW-1);
+
+       /* copy the interpreter name */
+       interp = imgp->ip_interp_buffer;
+       for ( ihp = line_startp; (ihp < line_endp) && !IS_WHITESPACE(*ihp); ihp++)
+               *interp++ = *ihp;
+       *interp = '\0';
+
+       exec_reset_save_path(imgp);
+       exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_buffer),
+                                                       UIO_SYSSPACE);
+
+       /* Copy the entire interpreter + args for later processing into argv[] */
+       interp = imgp->ip_interp_buffer;
+       for ( ihp = line_startp; (ihp < line_endp); ihp++)
+               *interp++ = *ihp;
+       *interp = '\0';
 
        /*
-        * If we have a fat file, find "our" executable.
+        * If we have a SUID oder SGID script, create a file descriptor
+        * from the vnode and pass /dev/fd/%d instead of the actual
+        * path name so that the script does not get opened twice
         */
-       if (is_fat) {
-               /*
-                * Look up our architecture in the fat file.
-                */
-               lret = fatfile_getarch(vp, (vm_offset_t)fat_header, &fat_arch);
-               if (lret != LOAD_SUCCESS) {
-                       error = load_return_to_errno(lret);
-                       goto bad;
-               }
-               /* Read the Mach-O header out of it */
-               error = vn_rdwr(UIO_READ, vp, (caddr_t)&exdata.mach_header,
-                               sizeof (exdata.mach_header),
-                               fat_arch.offset,
-                               UIO_SYSSPACE, (IO_UNIT|IO_NODELOCKED), cred, &resid, p);
+       if (imgp->ip_origvattr->va_mode & (VSUID | VSGID)) {
+               p = vfs_context_proc(imgp->ip_vfs_context);
+               error = falloc(p, &fp, &fd, imgp->ip_vfs_context);
+               if (error)
+                       return(error);
 
-               if (error) {
-                       goto bad;
-               }
+               fp->f_fglob->fg_flag = FREAD;
+               fp->f_fglob->fg_ops = &vnops;
+               fp->f_fglob->fg_data = (caddr_t)imgp->ip_vp;
+               
+               proc_fdlock(p);
+               procfdtbl_releasefd(p, fd, NULL);
+               fp_drop(p, fd, fp, 1);
+               proc_fdunlock(p);
+               vnode_ref(imgp->ip_vp);
 
-               /* Did we read a complete header? */
-               if (resid) {
-                       error = EBADEXEC;
-                       goto bad;
-               }
+               imgp->ip_interp_sugid_fd = fd;
+       }
 
-               /* Is what we found a Mach-O executable */
-               if (mach_header->magic != MH_MAGIC) {
-                       error = ENOEXEC;
-                       goto bad;
-               }
+       return (-3);
+}
 
-               /*
-                *      Load the Mach-O file.
-                */
-        VOP_UNLOCK(vp, 0, p);
-               lret = load_machfile(vp, mach_header, fat_arch.offset,
-                                   fat_arch.size, &load_result);
-       } else {
-               /*
-                *      Load the Mach-O file.
-                */
-               VOP_UNLOCK(vp, 0, p);
-               lret = load_machfile(vp, mach_header, 0,
-                                   (u_long)vattr.va_size, &load_result);
-       }
 
-       if (lret != LOAD_SUCCESS) {
-               error = load_return_to_errno(lret);
+
+/*
+ * exec_fat_imgact
+ *
+ * Image activator for fat 1.0 binaries.  If the binary is fat, then we
+ * need to select an image from it internally, and make that the image
+ * we are going to attempt to execute.  At present, this consists of
+ * reloading the first page for the image with a first page from the
+ * offset location indicated by the fat header.
+ *
+ * Parameters; struct image_params *   image parameter block
+ *
+ * Returns:    -1                      not a fat binary (keep looking)
+ *             -2                      Success: encapsulated binary: reread
+ *             >0                      Failure: error number
+ *
+ * Important:  This image activator is byte order neutral.
+ *
+ * Note:       A return value other than -1 indicates subsequent image
+ *             activators should not be given the opportunity to attempt
+ *             to activate the image.
+ *
+ *             If we find an encapsulated binary, we make no assertions
+ *             about its  validity; instead, we leave that up to a rescan
+ *             for an activator to claim it, and, if it is claimed by one,
+ *             that activator is responsible for determining validity.
+ */
+static int
+exec_fat_imgact(struct image_params *imgp)
+{
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
+       kauth_cred_t cred = kauth_cred_proc_ref(p);
+       struct fat_header *fat_header = (struct fat_header *)imgp->ip_vdata;
+       struct _posix_spawnattr *psa = NULL;
+       struct fat_arch fat_arch;
+       int resid, error;
+       load_return_t lret;
+
+       /* Make sure it's a fat binary */
+       if ((fat_header->magic != FAT_MAGIC) &&
+            (fat_header->magic != FAT_CIGAM)) {
+               error = -1;
                goto bad;
        }
 
-       /* load_machfile() maps the vnode */
-       ubc_map(vp);
+       /* If posix_spawn binprefs exist, respect those prefs. */
+       psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
+       if (psa != NULL && psa->psa_binprefs[0] != 0) {
+               struct fat_arch *arches = (struct fat_arch *) (fat_header + 1);
+               int nfat_arch = 0, pr = 0, f = 0;
 
-       /*
-        * deal with set[ug]id.
-        */
-       p->p_flag &= ~P_SUGID;
-       if (((origvattr.va_mode & VSUID) != 0 &&
-           p->p_ucred->cr_uid != origvattr.va_uid)
-           || (origvattr.va_mode & VSGID) != 0 &&
-           p->p_ucred->cr_gid != origvattr.va_gid) {
-               p->p_ucred = crcopy(cred);
-#if KTRACE
-               /*
-                * If process is being ktraced, turn off - unless
-                * root set it.
-                */
-               if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) {
-                       vrele(p->p_tracep);
-                       p->p_tracep = NULL;
-                       p->p_traceflag = 0;
-               }
-#endif
-               if (origvattr.va_mode & VSUID)
-                       p->p_ucred->cr_uid = origvattr.va_uid;
-               if (origvattr.va_mode & VSGID)
-                       p->p_ucred->cr_gid = origvattr.va_gid;
+               nfat_arch = OSSwapBigToHostInt32(fat_header->nfat_arch);
+               /* Check each preference listed against all arches in header */
+               for (pr = 0; pr < NBINPREFS; pr++) {
+                       cpu_type_t pref = psa->psa_binprefs[pr];
+                       if (pref == 0) {
+                               /* No suitable arch in the pref list */
+                               error = EBADARCH;
+                               goto bad;
+                       }
 
-               set_security_token(p);
-               p->p_flag |= P_SUGID;
+                       if (pref == CPU_TYPE_ANY) {
+                               /* Fall through to regular grading */
+                               break;
+                       }
 
-               /* Radar 2261856; setuid security hole fix */
-               /* Patch from OpenBSD: A. Ramesh */
-               /*
-                * XXX For setuid processes, attempt to ensure that
-                * stdin, stdout, and stderr are already allocated.
-                * We do not want userland to accidentally allocate
-                * descriptors in this range which has implied meaning
-                * to libc.
-                */
-               for (i = 0; i < 3; i++) {
-                       extern struct fileops vnops;
-                       struct nameidata nd1;
-                       struct file *fp;
-                       int indx;
-
-                       if (p->p_fd->fd_ofiles[i] == NULL) {
-                               if ((error = falloc(p, &fp, &indx)) != 0)
-                                       continue;
-                               NDINIT(&nd1, LOOKUP, FOLLOW, UIO_SYSSPACE,
-                                   "/dev/null", p);
-                               if ((error = vn_open(&nd1, FREAD, 0)) != 0) {
-                                       ffree(fp);
-                                       p->p_fd->fd_ofiles[indx] = NULL;
-                                       break;
+                       for (f = 0; f < nfat_arch; f++) {
+                               cpu_type_t archtype = OSSwapBigToHostInt32(
+                                               arches[f].cputype);
+                               cpu_type_t archsubtype = OSSwapBigToHostInt32(
+                                               arches[f].cpusubtype) & ~CPU_SUBTYPE_MASK;
+                               if (pref == archtype &&
+                                       grade_binary(archtype, archsubtype)) {
+                                       /* We have a winner! */
+                                       fat_arch.cputype = archtype; 
+                                       fat_arch.cpusubtype = archsubtype; 
+                                       fat_arch.offset = OSSwapBigToHostInt32(
+                                                       arches[f].offset);
+                                       fat_arch.size = OSSwapBigToHostInt32(
+                                                       arches[f].size);
+                                       fat_arch.align = OSSwapBigToHostInt32(
+                                                       arches[f].align);
+                                       goto use_arch;
                                }
-                               fp->f_flag = FREAD;
-                               fp->f_type = DTYPE_VNODE;
-                               fp->f_ops = &vnops;
-                               fp->f_data = (caddr_t)nd1.ni_vp;
-                               VOP_UNLOCK(nd1.ni_vp, 0, p);
                        }
                }
        }
-       p->p_cred->p_svuid = p->p_ucred->cr_uid;
-       p->p_cred->p_svgid = p->p_ucred->cr_gid;
 
-       if (p->p_flag & P_TRACED) {
-               psignal(p, SIGTRAP);
-#ifdef BSD_USE_APC
-               thread_apc_set(current_act(), bsd_ast);
-#else
-               ast_on(AST_BSD);
-#endif
+       /* Look up our preferred architecture in the fat file. */
+       lret = fatfile_getarch_affinity(imgp->ip_vp,
+                                       (vm_offset_t)fat_header,
+                                       &fat_arch,
+                                       (p->p_flag & P_AFFINITY));
+       if (lret != LOAD_SUCCESS) {
+               error = load_return_to_errno(lret);
+               goto bad;
        }
 
+use_arch:
+       /* Read the Mach-O header out of fat_arch */
+       error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata,
+                       PAGE_SIZE, fat_arch.offset,
+                       UIO_SYSSPACE, (IO_UNIT|IO_NODELOCKED),
+                       cred, &resid, p);
        if (error) {
                goto bad;
        }
-       VOP_LOCK(vp,  LK_EXCLUSIVE | LK_RETRY, p);
-       vput(vp);
-       vp = NULL;
-       
-       if (load_result.unixproc &&
-               create_unix_stack(current_map(),
-                                 load_result.user_stack, p)) {
-               error = load_return_to_errno(LOAD_NOSPACE);
+
+       /* Did we read a complete header? */
+       if (resid) {
+               error = EBADEXEC;
                goto bad;
        }
 
-       /*
-        * Copy back arglist if necessary.
-        */
+       /* Success.  Indicate we have identified an encapsulated binary */
+       error = -2;
+       imgp->ip_arch_offset = (user_size_t)fat_arch.offset;
+       imgp->ip_arch_size = (user_size_t)fat_arch.size;
 
-       ucp = p->user_stack;
-       if (load_result.unixproc) {
-               int pathptr;
-               
-               ucp = ucp - nc - NBPW;  /* begining of the STRING AREA */
+bad:
+       kauth_cred_unref(&cred);
+       return (error);
+}
 
-               /*
-                * Support for new app package launching for Mac OS X allocates
-                * the "path" at the begining of the execargs buffer.
-                * copy it just before the string area.
-                */
-                savedpathlen = (savedpathlen + NBPW-1) & ~(NBPW-1);
-               len = 0;
-               pathptr = ucp - savedpathlen;
-               error = copyoutstr(savedpath, (caddr_t)pathptr,
-                                       (unsigned)savedpathlen, &len);
-               if (error)
-                       goto bad;
-               
-               /* Save a NULL pointer below it */
-               (void) suword((caddr_t)(pathptr - NBPW), 0);
+/*
+ * exec_mach_imgact
+ *
+ * Image activator for mach-o 1.0 binaries.
+ *
+ * Parameters; struct image_params *   image parameter block
+ *
+ * Returns:    -1                      not a fat binary (keep looking)
+ *             -2                      Success: encapsulated binary: reread
+ *             >0                      Failure: error number
+ *             EBADARCH                Mach-o binary, but with an unrecognized
+ *                                     architecture
+ *             ENOMEM                  No memory for child process after -
+ *                                     can only happen after vfork()
+ *
+ * Important:  This image activator is NOT byte order neutral.
+ *
+ * Note:       A return value other than -1 indicates subsequent image
+ *             activators should not be given the opportunity to attempt
+ *             to activate the image.
+ *
+ * TODO:       More gracefully handle failures after vfork
+ */
+static int
+exec_mach_imgact(struct image_params *imgp)
+{
+       struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata;
+       proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
+       int                     error = 0;
+       int                     vfexec = 0;
+       task_t                  task;
+       task_t                  new_task = NULL; /* protected by vfexec */
+       thread_t                thread;
+       struct uthread          *uthread;
+       vm_map_t old_map = VM_MAP_NULL;
+       vm_map_t map;
+       load_return_t           lret;
+       load_result_t           load_result;
+       struct _posix_spawnattr *psa = NULL;
+       int spawn = (imgp->ip_flags & IMGPF_SPAWN);
 
-               /* Save the pointer to "path" just below it */
-               (void) suword((caddr_t)(pathptr - 2*NBPW), pathptr);
+       /*
+        * make sure it's a Mach-O 1.0 or Mach-O 2.0 binary; the difference
+        * is a reserved field on the end, so for the most part, we can
+        * treat them as if they were identical. Reverse-endian Mach-O
+        * binaries are recognized but not compatible.
+        */
+       if ((mach_header->magic == MH_CIGAM) ||
+           (mach_header->magic == MH_CIGAM_64)) {
+               error = EBADARCH;
+               goto bad;
+       }
 
-               /*
-                * na includes arg[] and env[].
-                * NBPW for 2 NULL one each ofter arg[argc -1] and env[n]
-                * NBPW for argc
-                * skip over saved path, NBPW for pointer to path,
-                * and NBPW for the NULL after pointer to path.
-                */
-               ap = ucp - na*NBPW - 3*NBPW - savedpathlen - 2*NBPW;
-               uthread->uu_ar0[SP] = ap;
-               (void) suword((caddr_t)ap, na-ne); /* argc */
-               nc = 0;
-               cc = 0;
-
-               cp = (char *) execargsp;
-               cc = NCARGS - savedpathlen - 2*NBPW;
-               ps.ps_argvstr = (char *)ucp;    /* first argv string */
-               ps.ps_nargvstr = na - ne;               /* argc */
-               for (;;) {
-                       ap += NBPW;
-                       if (na == ne) {
-                               (void) suword((caddr_t)ap, 0);
-                               ap += NBPW;
-                               ps.ps_envstr = (char *)ucp;
-                               ps.ps_nenvstr = ne;
-                       }
-                       if (--na < 0)
-                               break;
-                       (void) suword((caddr_t)ap, ucp);
-                       do {
-                               error = copyoutstr(cp, (caddr_t)ucp,
-                                                  (unsigned)cc, &len);
-                               ucp += len;
-                               cp += len;
-                               nc += len;
-                               cc -= len;
-                       } while (error == ENAMETOOLONG);
-                       if (error == EFAULT)
-                               break;  /* bad stack - user's problem */
-               }
-               (void) suword((caddr_t)ap, 0);
+       if ((mach_header->magic != MH_MAGIC) &&
+           (mach_header->magic != MH_MAGIC_64)) {
+               error = -1;
+               goto bad;
        }
-       
-       if (load_result.dynlinker) {
-               ap = uthread->uu_ar0[SP] -= 4;
-               (void) suword((caddr_t)ap, load_result.mach_header);
+
+       switch (mach_header->filetype) {
+       case MH_DYLIB:
+       case MH_BUNDLE:
+               error = -1;
+               goto bad;
        }
 
-#if defined(i386) || defined(ppc)
-       uthread->uu_ar0[PC] = load_result.entry_point;
-#else
-#error architecture not implemented!
-#endif 
+       if (!imgp->ip_origcputype) {
+               imgp->ip_origcputype = mach_header->cputype;
+               imgp->ip_origcpusubtype = mach_header->cpusubtype;
+       }
+
+       task = current_task();
+       thread = current_thread();
+       uthread = get_bsdthread_info(thread);
+
+       /*
+        * Save off the vfexec state up front; we have to do this, because
+        * we need to know if we were in this state initially subsequent to
+        * creating the backing task, thread, and uthread for the child
+        * process (from the vfs_context_t from in img_parms).
+        */
+       if (uthread->uu_flag & UT_VFORK)
+               vfexec = 1;      /* Mark in exec */
+
+       if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64)
+               imgp->ip_flags |= IMGPF_IS_64BIT;
+
+       /* If posix_spawn binprefs exist, respect those prefs. */
+       psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
+       if (psa != NULL && psa->psa_binprefs[0] != 0) {
+               int pr = 0;
+               for (pr = 0; pr < NBINPREFS; pr++) {
+                       cpu_type_t pref = psa->psa_binprefs[pr];
+                       if (pref == 0) {
+                               /* No suitable arch in the pref list */
+                               error = EBADARCH;
+                               goto bad;
+                       }
+
+                       if (pref == CPU_TYPE_ANY) {
+                               /* Jump to regular grading */
+                               goto grade;
+                       }
+
+                       if (pref == imgp->ip_origcputype) {
+                               /* We have a match! */
+                               goto grade;
+                       }
+               }
+               error = EBADARCH;
+               goto bad;
+       }
+grade:
+       if (!grade_binary(imgp->ip_origcputype, imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK)) {
+               error = EBADARCH;
+               goto bad;
+       }
+
+       /* Copy in arguments/environment from the old process */
+       error = exec_extract_strings(imgp);
+       if (error)
+               goto bad;
+
+       error = exec_add_apple_strings(imgp);
+       if (error)
+               goto bad;
+
+       AUDIT_ARG(argv, imgp->ip_startargv, imgp->ip_argc, 
+           imgp->ip_endargv - imgp->ip_startargv);
+       AUDIT_ARG(envv, imgp->ip_endargv, imgp->ip_envc,
+           imgp->ip_endenvv - imgp->ip_endargv);
+
+       /*
+        * We are being called to activate an image subsequent to a vfork()
+        * operation; in this case, we know that our task, thread, and
+        * uthread are actually those of our parent, and our proc, which we
+        * obtained indirectly from the image_params vfs_context_t, is the
+        * new child process.
+        */
+       if (vfexec || spawn) {
+               if (vfexec) {
+                       imgp->ip_new_thread = fork_create_child(task, p, FALSE, (imgp->ip_flags & IMGPF_IS_64BIT));
+                       if (imgp->ip_new_thread == NULL) {
+                               error = ENOMEM;
+                               goto bad;
+                       }
+               }
+
+               /* reset local idea of thread, uthread, task */
+               thread = imgp->ip_new_thread;
+               uthread = get_bsdthread_info(thread);
+               task = new_task = get_threadtask(thread);
+               map = get_task_map(task);
+       } else {
+               map = VM_MAP_NULL;
+       }
+
+       /*
+        * We set these flags here; this is OK, since if we fail after
+        * this point, we have already destroyed the parent process anyway.
+        */
+       task_set_dyld_info(task, MACH_VM_MIN_ADDRESS, 0);
+       if (imgp->ip_flags & IMGPF_IS_64BIT) {
+               task_set_64bit(task, TRUE);
+               OSBitOrAtomic(P_LP64, &p->p_flag);
+       } else {
+               task_set_64bit(task, FALSE);
+               OSBitAndAtomic(~((uint32_t)P_LP64), &p->p_flag);
+       }
+
+       /*
+        *      Load the Mach-O file.
+        *
+        * NOTE: An error after this point  indicates we have potentially
+        * destroyed or overwritten some process state while attempting an
+        * execve() following a vfork(), which is an unrecoverable condition.
+        */
+
+       /*
+        * Actually load the image file we previously decided to load.
+        */
+       lret = load_machfile(imgp, mach_header, thread, map, &load_result);
+
+       if (lret != LOAD_SUCCESS) {
+               error = load_return_to_errno(lret);
+               goto badtoolate;
+       }
+
+       vm_map_set_user_wire_limit(get_task_map(task), p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur);
+
+       /* 
+        * Set code-signing flags if this binary is signed, or if parent has
+        * requested them on exec.
+        */
+       if (load_result.csflags & CS_VALID) {
+               imgp->ip_csflags |= load_result.csflags & 
+                       (CS_VALID|
+                        CS_HARD|CS_KILL|CS_ENFORCEMENT|
+                        CS_EXEC_SET_HARD|CS_EXEC_SET_KILL|CS_EXEC_SET_ENFORCEMENT);
+       } else {
+               imgp->ip_csflags &= ~CS_VALID;
+       }
+
+       if (p->p_csflags & CS_EXEC_SET_HARD)
+               imgp->ip_csflags |= CS_HARD;
+       if (p->p_csflags & CS_EXEC_SET_KILL)
+               imgp->ip_csflags |= CS_KILL;
+       if (p->p_csflags & CS_EXEC_SET_ENFORCEMENT)
+               imgp->ip_csflags |= CS_ENFORCEMENT;
+
+
+       /*
+        * Set up the system reserved areas in the new address space.
+        */
+       vm_map_exec(get_task_map(task),
+                   task,
+                   (void *) p->p_fd->fd_rdir,
+                   cpu_type());
+       
+       /*
+        * Close file descriptors which specify close-on-exec.
+        */
+       fdexec(p, psa != NULL ? psa->psa_flags : 0);
+
+       /*
+        * deal with set[ug]id.
+        */
+       error = exec_handle_sugid(imgp);
+
+       /* Make sure we won't interrupt ourself signalling a partial process */
+       if (!vfexec && !spawn && (p->p_lflag & P_LTRACED))
+               psignal(p, SIGTRAP);
+
+       if (error) {
+               goto badtoolate;
+       }
+       
+       if (load_result.unixproc &&
+               create_unix_stack(get_task_map(task),
+                                 &load_result,
+                                 p) != KERN_SUCCESS) {
+               error = load_return_to_errno(LOAD_NOSPACE);
+               goto badtoolate;
+       }
+
+       if (vfexec || spawn) {
+               old_map = vm_map_switch(get_task_map(task));
+       }
+
+       if (load_result.unixproc) {
+               user_addr_t     ap;
+
+               /*
+                * Copy the strings area out into the new process address
+                * space.
+                */
+               ap = p->user_stack;
+               error = exec_copyout_strings(imgp, &ap);
+               if (error) {
+                       if (vfexec || spawn)
+                               vm_map_switch(old_map);
+                       goto badtoolate;
+               }
+               /* Set the stack */
+               thread_setuserstack(thread, ap);
+       }
+       
+       if (load_result.dynlinker) {
+               uint64_t        ap;
+               int                     new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4;
+
+               /* Adjust the stack */
+               ap = thread_adjuserstack(thread, -new_ptr_size);
+               error = copyoutptr(load_result.mach_header, ap, new_ptr_size);
+
+               if (error) {
+                       if (vfexec || spawn)
+                               vm_map_switch(old_map);
+                       goto badtoolate;
+               }
+               task_set_dyld_info(task, load_result.all_image_info_addr,
+                   load_result.all_image_info_size);
+       }
+
+       /* Avoid immediate VM faults back into kernel */
+       exec_prefault_data(p, imgp, &load_result);
+
+       if (vfexec || spawn) {
+               vm_map_switch(old_map);
+       }
+       /* Set the entry point */
+       thread_setentrypoint(thread, load_result.entry_point);
 
        /* Stop profiling */
        stopprofclock(p);
@@ -657,252 +963,3393 @@ again:
        /*
         * Reset signal state.
         */
-       execsigs(p);
+       execsigs(p, thread);
 
        /*
-        * Close file descriptors
-        * which specify close-on-exec.
+        * need to cancel async IO requests that can be cancelled and wait for those
+        * already active.  MAY BLOCK!
         */
-       fdexec(p);
+       _aio_exec( p );
+
+#if SYSV_SHM
        /* FIXME: Till vmspace inherit is fixed: */
-       if (p->vm_shm)
-               shmexit(p);
+       if (!vfexec && p->vm_shm)
+               shmexec(p);
+#endif
+#if SYSV_SEM
+       /* Clean up the semaphores */
+       semexit(p);
+#endif
 
        /*
         * Remember file name for accounting.
         */
        p->p_acflag &= ~AFORK;
-       if (nd.ni_cnd.cn_namelen > MAXCOMLEN)
-               nd.ni_cnd.cn_namelen = MAXCOMLEN;
-       bcopy((caddr_t)nd.ni_cnd.cn_nameptr, (caddr_t)p->p_comm,
-           (unsigned)nd.ni_cnd.cn_namelen);
-       p->p_comm[nd.ni_cnd.cn_namelen] = '\0';
+       /* If the translated name isn't NULL, then we want to use
+        * that translated name as the name we show as the "real" name.
+        * Otherwise, use the name passed into exec.
+        */
+       if (0 != imgp->ip_p_comm[0]) {
+               bcopy((caddr_t)imgp->ip_p_comm, (caddr_t)p->p_comm,
+                       sizeof(p->p_comm));
+       } else {
+               if (imgp->ip_ndp->ni_cnd.cn_namelen > MAXCOMLEN)
+                       imgp->ip_ndp->ni_cnd.cn_namelen = MAXCOMLEN;
+               bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_comm,
+                       (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen);
+               p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0';
+       }
+
+       pal_dbg_set_task_name( p->task );
+
+       memcpy(&p->p_uuid[0], &load_result.uuid[0], sizeof(p->p_uuid));
+
+// <rdar://6598155> dtrace code cleanup needed
+#if CONFIG_DTRACE
+       /*
+        * Invalidate any predicate evaluation already cached for this thread by DTrace.
+        * That's because we've just stored to p_comm and DTrace refers to that when it
+        * evaluates the "execname" special variable. uid and gid may have changed as well.
+        */
+       dtrace_set_thread_predcache(current_thread(), 0);
+
+       /*
+        * Free any outstanding lazy dof entries. It is imperative we
+        * always call dtrace_lazy_dofs_destroy, rather than null check
+        * and call if !NULL. If we NULL test, during lazy dof faulting
+        * we can race with the faulting code and proceed from here to
+        * beyond the helpers cleanup. The lazy dof faulting will then
+        * install new helpers which no longer belong to this process!
+        */
+       dtrace_lazy_dofs_destroy(p);
+
+
+       /*
+        * Clean up any DTrace helpers for the process.
+        */
+       if (p->p_dtrace_helpers != NULL && dtrace_helpers_cleanup) {
+               (*dtrace_helpers_cleanup)(p);
+       }
+       
+       /*
+        * Cleanup the DTrace provider associated with this process.
+        */
+       proc_lock(p);
+       if (p->p_dtrace_probes && dtrace_fasttrap_exec_ptr) {
+               (*dtrace_fasttrap_exec_ptr)(p);
+       }
+       proc_unlock(p);
+#endif
+
+       if (kdebug_enable) {
+               long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4;
+
+               /*
+                * Collect the pathname for tracing
+                */
+               kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4);
+
+               if (vfexec || spawn) {
+                       KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE,
+                                       p->p_pid ,0,0,0, (uintptr_t)thread_tid(thread));
+                       KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
+                                       dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (uintptr_t)thread_tid(thread));
+               } else {
+                       KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE,
+                                       p->p_pid ,0,0,0,0);
+                       KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
+                                       dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, 0);
+               }
+       }
 
-       {
-         /* This is for kdebug */
-         long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4;
+       /*
+        * Ensure the 'translated' and 'affinity' flags are cleared, since we
+        * no longer run PowerPC binaries.
+        */
+       OSBitAndAtomic(~((uint32_t)(P_TRANSLATED | P_AFFINITY)), &p->p_flag);
+
+       /*
+        * If posix_spawned with the START_SUSPENDED flag, stop the
+        * process before it runs.
+        */
+       if (imgp->ip_px_sa != NULL) {
+               psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
+               if (psa->psa_flags & POSIX_SPAWN_START_SUSPENDED) {
+                       proc_lock(p);
+                       p->p_stat = SSTOP;
+                       proc_unlock(p);
+                       (void) task_suspend(p->task);
+               }
+       }
 
-         /* Collect the pathname for tracing */
-         kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4);
-         KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
-                               dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, 0);
+       /*
+        * Apply the apptype state (which primes the task for importance donation)
+        * This must be done after the exec so that the child's thread is ready 
+        */
+       if (imgp->ip_px_sa != NULL) {
+               psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
+               exec_handle_spawnattr_apptype(p, psa->psa_apptype);
        }
 
        /*
         * mark as execed, wakeup the process that vforked (if any) and tell
-        * it that it now has it's own resources back
+        * it that it now has its own resources back
         */
-       p->p_flag |= P_EXEC;
-       if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
-               p->p_flag &= ~P_PPWAIT;
+       OSBitOrAtomic(P_EXEC, &p->p_flag);
+       proc_resetregister(p);
+       if (p->p_pptr && (p->p_lflag & P_LPPWAIT)) {
+               proc_lock(p);
+               p->p_lflag &= ~P_LPPWAIT;
+               proc_unlock(p);
                wakeup((caddr_t)p->p_pptr);
        }
 
+       /*
+        * Pay for our earlier safety; deliver the delayed signals from
+        * the incomplete vfexec process now that it's complete.
+        */
+       if (vfexec && (p->p_lflag & P_LTRACED)) {
+               psignal_vfork(p, new_task, thread, SIGTRAP);
+       }
+
+badtoolate:
+if (!spawn)
+       /* notify only if it has not failed due to FP Key error */
+       if ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)
+               proc_knote(p, NOTE_EXEC);
+
+       if (vfexec || spawn) {
+               task_deallocate(new_task);
+               thread_deallocate(thread);
+               if (error)
+                       error = 0;
+       }
+
 bad:
-       FREE_ZONE(nd.ni_cnd.cn_pnbuf, nd.ni_cnd.cn_pnlen, M_NAMEI);
-       if (vp)
-               vput(vp);
-bad1:
-#if FIXME  /* [ */
-       if (execargs)
-               kmem_free_wakeup(bsd_pageable_map, execargs, NCARGS);
-#else  /* FIXME ][ */
-       if (execargs)
-               kmem_free(bsd_pageable_map, execargs, NCARGS);
-#endif  /* FIXME ] */
        return(error);
 }
 
 
-#define        unix_stack_size(p)      (p->p_rlimit[RLIMIT_STACK].rlim_cur)
 
-kern_return_t
-create_unix_stack(map, user_stack, p)
-       vm_map_t        map;
-       vm_offset_t     user_stack;
-       struct proc     *p;
-{
-       vm_size_t       size;
-       vm_offset_t     addr;
 
-       p->user_stack = user_stack;
-       size = round_page(unix_stack_size(p));
-#if    STACK_GROWTH_UP
-       /* stack always points to first address for stacks */
-       addr = user_stack;
-#else  STACK_GROWTH_UP
-       addr = trunc_page(user_stack - size);
-#endif /* STACK_GROWTH_UP */
-       return (vm_allocate(map,&addr, size, FALSE));
-}
+/*
+ * Our image activator table; this is the table of the image types we are
+ * capable of loading.  We list them in order of preference to ensure the
+ * fastest image load speed.
+ *
+ * XXX hardcoded, for now; should use linker sets
+ */
+struct execsw {
+       int (*ex_imgact)(struct image_params *);
+       const char *ex_name;
+} execsw[] = {
+       { exec_mach_imgact,             "Mach-o Binary" },
+       { exec_fat_imgact,              "Fat Binary" },
+       { exec_shell_imgact,            "Interpreter Script" },
+       { NULL, NULL}
+};
 
-#include <sys/reboot.h>
 
-char           init_program_name[128] = "/sbin/mach_init\0";
+/*
+ * exec_activate_image
+ *
+ * Description:        Iterate through the available image activators, and activate
+ *             the image associated with the imgp structure.  We start with
+ *             the
+ *
+ * Parameters: struct image_params *   Image parameter block
+ *
+ * Returns:    0                       Success
+ *             EBADEXEC                The executable is corrupt/unknown
+ *     execargs_alloc:EINVAL           Invalid argument
+ *     execargs_alloc:EACCES           Permission denied
+ *     execargs_alloc:EINTR            Interrupted function
+ *     execargs_alloc:ENOMEM           Not enough space
+ *     exec_save_path:EFAULT           Bad address
+ *     exec_save_path:ENAMETOOLONG     Filename too long
+ *     exec_check_permissions:EACCES   Permission denied
+ *     exec_check_permissions:ENOEXEC  Executable file format error
+ *     exec_check_permissions:ETXTBSY  Text file busy [misuse of error code]
+ *     exec_check_permissions:???
+ *     namei:???
+ *     vn_rdwr:???                     [anything vn_rdwr can return]
+ *     <ex_imgact>:???                 [anything an imgact can return]
+ */
+static int
+exec_activate_image(struct image_params *imgp)
+{
+       struct nameidata nd;
+       int error;
+       int resid;
+       int once = 1;   /* save SGUID-ness for interpreted files */
+       int i;
+       int iterlimit = EAI_ITERLIMIT;
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
 
-char           init_args[128] = "";
+       error = execargs_alloc(imgp);
+       if (error)
+               goto bad_notrans;
+       
+       error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg);
+       if (error) {
+               goto bad_notrans;
+       }
 
-struct execve_args     init_exec_args;
-int            init_attempts = 0;
+       /* Use imgp->ip_strings, which contains the copyin-ed exec path */
+       DTRACE_PROC1(exec, uintptr_t, imgp->ip_strings);
 
+       NDINIT(&nd, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
+                  UIO_SYSSPACE, CAST_USER_ADDR_T(imgp->ip_strings), imgp->ip_vfs_context);
 
-void
-load_init_program(p)
-       struct proc *p;
-{
-       vm_offset_t     init_addr;
-       int             *old_ap;
-       char            *argv[3];
-       int             error;
-       register_t retval[2];
-       struct uthread * ut;
+again:
+       error = namei(&nd);
+       if (error)
+               goto bad_notrans;
+       imgp->ip_ndp = &nd;     /* successful namei(); call nameidone() later */
+       imgp->ip_vp = nd.ni_vp; /* if set, need to vnode_put() at some point */
 
-       unix_master();
+       /*
+        * Before we start the transition from binary A to binary B, make
+        * sure another thread hasn't started exiting the process.  We grab
+        * the proc lock to check p_lflag initially, and the transition
+        * mechanism ensures that the value doesn't change after we release
+        * the lock.
+        */
+       proc_lock(p);
+       if (p->p_lflag & P_LEXIT) {
+               proc_unlock(p);
+               goto bad_notrans;
+       }
+       error = proc_transstart(p, 1);
+       proc_unlock(p);
+       if (error)
+               goto bad_notrans;
 
-       error = 0;
+       error = exec_check_permissions(imgp);
+       if (error)
+               goto bad;
 
-       /* init_args are copied in string form directly from bootstrap */
-       
-       do {
-               if (boothowto & RB_INITNAME) {
-                       printf("init program? ");
-#if FIXME  /* [ */
-                       gets(init_program_name, init_program_name);
-#endif  /* FIXME ] */
-               }
-
-               if (error && ((boothowto & RB_INITNAME) == 0) &&
-                                       (init_attempts == 1)) {
-                       static char other_init[] = "/etc/mach_init";
-                       printf("Load of %s, errno %d, trying %s\n",
-                               init_program_name, error, other_init);
-                       error = 0;
-                       bcopy(other_init, init_program_name,
-                                                       sizeof(other_init));
-               }
+       /* Copy; avoid invocation of an interpreter overwriting the original */
+       if (once) {
+               once = 0;
+               *imgp->ip_origvattr = *imgp->ip_vattr;
+       }
 
-               init_attempts++;
+       error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0,
+                       UIO_SYSSPACE, IO_NODELOCKED,
+                       vfs_context_ucred(imgp->ip_vfs_context),
+                       &resid, vfs_context_proc(imgp->ip_vfs_context));
+       if (error)
+               goto bad;
+               
+encapsulated_binary:
+       /* Limit the number of iterations we will attempt on each binary */
+       if (--iterlimit == 0) {
+               error = EBADEXEC;
+               goto bad;
+       }
+       error = -1;
+       for(i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) {
 
-               if (error) {
-                       printf("Load of %s failed, errno %d\n",
-                                       init_program_name, error);
-                       error = 0;
-                       boothowto |= RB_INITNAME;
-                       continue;
-               }
+               error = (*execsw[i].ex_imgact)(imgp);
 
-               /*
-                *      Copy out program name.
-                */
+               switch (error) {
+               /* case -1: not claimed: continue */
+               case -2:                /* Encapsulated binary */
+                       goto encapsulated_binary;
 
-               init_addr = VM_MIN_ADDRESS;
-               (void) vm_allocate(current_map(), &init_addr,
-                                  PAGE_SIZE, TRUE);
-               if (init_addr == 0)
-                       init_addr++;
-               (void) copyout((caddr_t) init_program_name,
-                               (caddr_t) (init_addr),
-                               (unsigned) sizeof(init_program_name)+1);
-
-               argv[0] = (char *) init_addr;
-               init_addr += sizeof(init_program_name);
-               init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
+               case -3:                /* Interpreter */
+#if CONFIG_MACF
+                       /*
+                        * Copy the script label for later use. Note that
+                        * the label can be different when the script is
+                        * actually read by the interpreter.
+                        */
+                       if (imgp->ip_scriptlabelp)
+                               mac_vnode_label_free(imgp->ip_scriptlabelp);
+                       imgp->ip_scriptlabelp = mac_vnode_label_alloc();
+                       if (imgp->ip_scriptlabelp == NULL) {
+                               error = ENOMEM;
+                               break;
+                       }
+                       mac_vnode_label_copy(imgp->ip_vp->v_label,
+                                            imgp->ip_scriptlabelp);
 
-               /*
-                *      Put out first (and only) argument, similarly.
-                *      Assumes everything fits in a page as allocated
-                *      above.
-                */
+                       /*
+                        * Take a ref of the script vnode for later use.
+                        */
+                       if (imgp->ip_scriptvp)
+                               vnode_put(imgp->ip_scriptvp);
+                       if (vnode_getwithref(imgp->ip_vp) == 0)
+                               imgp->ip_scriptvp = imgp->ip_vp;
+#endif
 
-               (void) copyout((caddr_t) init_args,
-                               (caddr_t) (init_addr),
-                               (unsigned) sizeof(init_args));
+                       nameidone(&nd);
 
-               argv[1] = (char *) init_addr;
-               init_addr += sizeof(init_args);
-               init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
+                       vnode_put(imgp->ip_vp);
+                       imgp->ip_vp = NULL;     /* already put */
+                       imgp->ip_ndp = NULL; /* already nameidone */
 
-               /*
-                *      Null-end the argument list
-                */
+                       /* Use imgp->ip_strings, which exec_shell_imgact reset to the interpreter */
+                       NDINIT(&nd, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF,
+                                  UIO_SYSSPACE, CAST_USER_ADDR_T(imgp->ip_strings), imgp->ip_vfs_context);
 
-               argv[2] = (char *) 0;
-               
-               /*
-                *      Copy out the argument list.
-                */
-               
-               (void) copyout((caddr_t) argv,
-                               (caddr_t) (init_addr),
-                               (unsigned) sizeof(argv));
+                       proc_transend(p, 0);
+                       goto again;
 
-               /*
-                *      Set up argument block for fake call to execve.
-                */
+               default:
+                       break;
+               }
+       }
 
-               init_exec_args.fname = argv[0];
-               init_exec_args.argp = (char **) init_addr;
-               init_exec_args.envp = 0;
-               
-               /* So that mach_init task 
-                * is set with uid,gid 0 token 
-                */
-               set_security_token(p);
+       /*
+        * Call out to allow 3rd party notification of exec. 
+        * Ignore result of kauth_authorize_fileop call.
+        */
+       if (error == 0 && kauth_authorize_fileop_has_listeners()) {
+               kauth_authorize_fileop(vfs_context_ucred(imgp->ip_vfs_context),
+                                       KAUTH_FILEOP_EXEC,
+                                       (uintptr_t)nd.ni_vp, 0);
+       }
+
+bad:
+       proc_transend(p, 0);
 
-               error = execve(p,&init_exec_args,retval);
-       } while (error);
+bad_notrans:
+       if (imgp->ip_strings)
+               execargs_free(imgp);
+       if (imgp->ip_ndp)
+               nameidone(imgp->ip_ndp);
 
-       unix_release();
+       return (error);
 }
 
+
 /*
- * Convert a load_return_t to an errno.
+ * exec_handle_spawnattr_apptype
+ *
+ * Description: Decode and apply the posix_spawn apptype to the task.
+ *
+ * Parameters:  proc_t p                process to apply attributes to
+ *              int psa_apptype         posix spawn attribute apptype
+ *
+ * Returns:     0                       Success
  */
-static int 
-load_return_to_errno(load_return_t lrtn)
+static errno_t
+exec_handle_spawnattr_apptype(proc_t p, int psa_apptype)
 {
-       switch (lrtn) {
-           case LOAD_SUCCESS:
-               return 0;
-           case LOAD_BADARCH:
-               return EBADARCH;
-           case LOAD_BADMACHO:
-               return EBADMACHO;
-           case LOAD_SHLIB:
-               return ESHLIBVERS;
-           case LOAD_NOSPACE:
-               return ENOMEM;
-           case LOAD_PROTECT:
-               return EACCES;
-           case LOAD_RESOURCE:
-           case LOAD_FAILURE:
-           default:
-               return EBADEXEC;
+       if ((psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK) != 0) {
+               int apptype = TASK_APPTYPE_NONE;
+               int proctype = psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK;
+
+               switch(proctype) {
+                       case POSIX_SPAWN_PROC_TYPE_DAEMON_INTERACTIVE:
+                               apptype = TASK_APPTYPE_DAEMON_INTERACTIVE;
+                               break;
+                       case POSIX_SPAWN_PROC_TYPE_DAEMON_STANDARD:
+                               apptype = TASK_APPTYPE_DAEMON_STANDARD;
+                               break;
+                       case POSIX_SPAWN_PROC_TYPE_DAEMON_ADAPTIVE:
+                               apptype = TASK_APPTYPE_DAEMON_ADAPTIVE;
+                               break;
+                       case POSIX_SPAWN_PROC_TYPE_DAEMON_BACKGROUND:
+                               apptype = TASK_APPTYPE_DAEMON_BACKGROUND;
+                               break;
+                       case POSIX_SPAWN_PROC_TYPE_APP_DEFAULT:
+                               apptype = TASK_APPTYPE_APP_DEFAULT;
+                               break;
+                       case POSIX_SPAWN_PROC_TYPE_APP_TAL:
+                               apptype = TASK_APPTYPE_APP_TAL;
+                               break;
+                       default:
+                               apptype = TASK_APPTYPE_NONE;
+                               break;
+               }
+
+               proc_set_task_apptype(p->task, apptype);
+
+               /* TODO: Should an invalid value here fail the spawn? */
+               return (0);
        }
+
+       return (0);
 }
 
+
 /*
- * exec_check_access()
+ * exec_handle_port_actions
+ *
+ * Description:        Go through the _posix_port_actions_t contents, 
+ *             calling task_set_special_port, task_set_exception_ports
+ *             and/or audit_session_spawnjoin for the current task.
+ *
+ * Parameters: struct image_params *   Image parameter block
+ *             short psa_flags         posix spawn attribute flags
+ *
+ * Returns:    0                       Success
+ *             EINVAL                  Failure
+ *             ENOTSUP                 Illegal posix_spawn attr flag was set
  */
-int
-check_exec_access(p, vp, vap)
-       struct proc  *p;
-       struct vnode *vp;
-       struct vattr *vap;
+static errno_t
+exec_handle_port_actions(struct image_params *imgp, short psa_flags, int * need_portwatch, ipc_port_t * portwatch_ports)
 {
-       int flag;
-       int error;
+       _posix_spawn_port_actions_t pacts = imgp->ip_px_spa;
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
+       _ps_port_action_t *act = NULL;
+       task_t task = p->task;
+       ipc_port_t port = NULL;
+       errno_t ret = 0;
+       int i;
 
-       if (error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p))
-               return (error);
-       flag = p->p_flag;
-       if (flag & P_TRACED) {
-               if (error = VOP_ACCESS(vp, VREAD, p->p_ucred, p))
-                       return (error);
-       }
-       if (vp->v_type != VREG ||
-           (vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)
-               return (EACCES);
-       return (0);
-}
+       if (need_portwatch != NULL)
+               *need_portwatch  = 0;
+
+       for (i = 0; i < pacts->pspa_count; i++) {
+               act = &pacts->pspa_actions[i];
+
+               if (ipc_object_copyin(get_task_ipcspace(current_task()),
+                   act->new_port, MACH_MSG_TYPE_COPY_SEND,
+                   (ipc_object_t *) &port) != KERN_SUCCESS) {
+                       ret = EINVAL;
+                       goto done;
+               }
+
+               switch (act->port_type) {
+               case PSPA_SPECIAL:
+                       /* Only allowed when not under vfork */
+                       if (!(psa_flags & POSIX_SPAWN_SETEXEC))
+                               ret = ENOTSUP;
+                       else if (task_set_special_port(task,
+                       act->which, port) != KERN_SUCCESS)
+                               ret = EINVAL;
+                       break;
+
+               case PSPA_EXCEPTION:
+                       /* Only allowed when not under vfork */
+                       if (!(psa_flags & POSIX_SPAWN_SETEXEC))
+                               ret = ENOTSUP;
+                       else if (task_set_exception_ports(task, 
+                       act->mask, port, act->behavior, 
+                       act->flavor) != KERN_SUCCESS)
+                               ret = EINVAL;
+                       break;
+#if CONFIG_AUDIT
+               case PSPA_AU_SESSION:
+                       ret = audit_session_spawnjoin(p, port);
+                       break;
+#endif
+               case PSPA_IMP_WATCHPORTS:
+                       if (portwatch_ports != NULL) {
+                               if (need_portwatch != NULL)
+                                       *need_portwatch  = 1;
+                               /* hold on to this till end of spawn */
+                               portwatch_ports[i] = port;
+                               ret = 0;
+                       } else
+                               ipc_port_release_send(port);
+                       break;
+               default:
+                       ret = EINVAL;
+                       break;
+               }
 
+               /* action failed, so release port resources */
+
+               if (ret) { 
+                       ipc_port_release_send(port);
+                       break;
+               }
+       }
+
+done:
+       if (0 != ret)
+               DTRACE_PROC1(spawn__port__failure, mach_port_name_t, act->new_port);
+       return (ret);
+}
+
+/*
+ * exec_handle_file_actions
+ *
+ * Description:        Go through the _posix_file_actions_t contents applying the
+ *             open, close, and dup2 operations to the open file table for
+ *             the current process.
+ *
+ * Parameters: struct image_params *   Image parameter block
+ *
+ * Returns:    0                       Success
+ *             ???
+ *
+ * Note:       Actions are applied in the order specified, with the credential
+ *             of the parent process.  This is done to permit the parent
+ *             process to utilize POSIX_SPAWN_RESETIDS to drop privilege in
+ *             the child following operations the child may in fact not be
+ *             normally permitted to perform.
+ */
+static int
+exec_handle_file_actions(struct image_params *imgp, short psa_flags)
+{
+       int error = 0;
+       int action;
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
+       _posix_spawn_file_actions_t px_sfap = imgp->ip_px_sfa;
+       int ival[2];            /* dummy retval for system calls) */
+
+       for (action = 0; action < px_sfap->psfa_act_count; action++) {
+               _psfa_action_t *psfa = &px_sfap->psfa_act_acts[ action];
+
+               switch(psfa->psfaa_type) {
+               case PSFA_OPEN: {
+                       /*
+                        * Open is different, in that it requires the use of
+                        * a path argument, which is normally copied in from
+                        * user space; because of this, we have to support an
+                        * open from kernel space that passes an address space
+                        * context of UIO_SYSSPACE, and casts the address
+                        * argument to a user_addr_t.
+                        */
+                       struct vnode_attr va;
+                       struct nameidata nd;
+                       int mode = psfa->psfaa_openargs.psfao_mode;
+                       struct dup2_args dup2a;
+                       struct close_nocancel_args ca;
+                       int origfd;
+
+                       VATTR_INIT(&va);
+                       /* Mask off all but regular access permissions */
+                       mode = ((mode &~ p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT;
+                       VATTR_SET(&va, va_mode, mode & ACCESSPERMS);
+
+                       NDINIT(&nd, LOOKUP, OP_OPEN, FOLLOW | AUDITVNPATH1, UIO_SYSSPACE,
+                              CAST_USER_ADDR_T(psfa->psfaa_openargs.psfao_path),
+                              imgp->ip_vfs_context);
+
+                       error = open1(imgp->ip_vfs_context, 
+                                       &nd,
+                                       psfa->psfaa_openargs.psfao_oflag,
+                                       &va,
+                                       fileproc_alloc_init, NULL,
+                                       ival);
+
+                       /*
+                        * If there's an error, or we get the right fd by
+                        * accident, then drop out here.  This is easier than
+                        * reworking all the open code to preallocate fd
+                        * slots, and internally taking one as an argument.
+                        */
+                       if (error || ival[0] == psfa->psfaa_filedes)
+                               break;
+
+                       origfd = ival[0];
+                       /*
+                        * If we didn't fall out from an error, we ended up
+                        * with the wrong fd; so now we've got to try to dup2
+                        * it to the right one.
+                        */
+                       dup2a.from = origfd;
+                       dup2a.to = psfa->psfaa_filedes;
+
+                       /*
+                        * The dup2() system call implementation sets
+                        * ival to newfd in the success case, but we
+                        * can ignore that, since if we didn't get the
+                        * fd we wanted, the error will stop us.
+                        */
+                       error = dup2(p, &dup2a, ival);
+                       if (error)
+                               break;
+
+                       /*
+                        * Finally, close the original fd.
+                        */
+                       ca.fd = origfd;
+
+                       error = close_nocancel(p, &ca, ival);
+                       }
+                       break;
+
+               case PSFA_DUP2: {
+                       struct dup2_args dup2a;
+
+                       dup2a.from = psfa->psfaa_filedes;
+                       dup2a.to = psfa->psfaa_openargs.psfao_oflag;
+
+                       /*
+                        * The dup2() system call implementation sets
+                        * ival to newfd in the success case, but we
+                        * can ignore that, since if we didn't get the
+                        * fd we wanted, the error will stop us.
+                        */
+                       error = dup2(p, &dup2a, ival);
+                       }
+                       break;
+
+               case PSFA_CLOSE: {
+                       struct close_nocancel_args ca;
+
+                       ca.fd = psfa->psfaa_filedes;
+
+                       error = close_nocancel(p, &ca, ival);
+                       }
+                       break;
+
+               case PSFA_INHERIT: {
+                       struct fcntl_nocancel_args fcntla;
+
+                       /*
+                        * Check to see if the descriptor exists, and
+                        * ensure it's -not- marked as close-on-exec.
+                        *
+                        * Attempting to "inherit" a guarded fd will
+                        * result in a error.
+                        */
+                       fcntla.fd = psfa->psfaa_filedes;
+                       fcntla.cmd = F_GETFD;
+                       if ((error = fcntl_nocancel(p, &fcntla, ival)) != 0)
+                               break;
+
+                       if ((ival[0] & FD_CLOEXEC) == FD_CLOEXEC) {
+                               fcntla.fd = psfa->psfaa_filedes;
+                               fcntla.cmd = F_SETFD;
+                               fcntla.arg = ival[0] & ~FD_CLOEXEC;
+                               error = fcntl_nocancel(p, &fcntla, ival);
+                       }
+
+                       }
+                       break;
+
+               default:
+                       error = EINVAL;
+                       break;
+               }
+
+               /* All file actions failures are considered fatal, per POSIX */
+
+               if (error) {
+                       if (PSFA_OPEN == psfa->psfaa_type) {
+                               DTRACE_PROC1(spawn__open__failure, uintptr_t,
+                                   psfa->psfaa_openargs.psfao_path);
+                       } else {
+                               DTRACE_PROC1(spawn__fd__failure, int, psfa->psfaa_filedes);
+                       }
+                       break;
+               }
+       }
+
+       if (error != 0 || (psa_flags & POSIX_SPAWN_CLOEXEC_DEFAULT) == 0)
+               return (error);
+
+       /*
+        * If POSIX_SPAWN_CLOEXEC_DEFAULT is set, behave (during
+        * this spawn only) as if "close on exec" is the default
+        * disposition of all pre-existing file descriptors.  In this case,
+        * the list of file descriptors mentioned in the file actions
+        * are the only ones that can be inherited, so mark them now.
+        *
+        * The actual closing part comes later, in fdexec().
+        */
+       proc_fdlock(p);
+       for (action = 0; action < px_sfap->psfa_act_count; action++) {
+               _psfa_action_t *psfa = &px_sfap->psfa_act_acts[action];
+               int fd = psfa->psfaa_filedes;
+
+               switch (psfa->psfaa_type) {
+               case PSFA_DUP2:
+                       fd = psfa->psfaa_openargs.psfao_oflag;
+                       /*FALLTHROUGH*/
+               case PSFA_OPEN:
+               case PSFA_INHERIT:
+                       *fdflags(p, fd) |= UF_INHERIT;
+                       break;
+
+               case PSFA_CLOSE:
+                       break;
+               }
+       }
+       proc_fdunlock(p);
+
+       return (0);
+}
+
+#if CONFIG_MACF
+/*
+ * exec_spawnattr_getmacpolicyinfo
+ */
+void *
+exec_spawnattr_getmacpolicyinfo(const void *macextensions, const char *policyname, size_t *lenp)
+{
+       const struct _posix_spawn_mac_policy_extensions *psmx = macextensions;
+       int i;
+
+       if (psmx == NULL)
+               return NULL;
+
+       for (i = 0; i < psmx->psmx_count; i++) {
+               const _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i];
+               if (strncmp(extension->policyname, policyname, sizeof(extension->policyname)) == 0) {
+                       if (lenp != NULL)
+                               *lenp = extension->datalen;
+                       return extension->datap;
+               }
+       }
+
+       if (lenp != NULL)
+               *lenp = 0;
+       return NULL;
+}
+
+static int
+spawn_copyin_macpolicyinfo(const struct user__posix_spawn_args_desc *px_args, _posix_spawn_mac_policy_extensions_t *psmxp)
+{
+       _posix_spawn_mac_policy_extensions_t psmx = NULL;
+       int error = 0;
+       int copycnt = 0;
+       int i = 0;
+
+       *psmxp = NULL;
+
+       if (px_args->mac_extensions_size < PS_MAC_EXTENSIONS_SIZE(1) ||
+           px_args->mac_extensions_size > PAGE_SIZE) {
+               error = EINVAL;
+               goto bad;
+       }
+
+       MALLOC(psmx, _posix_spawn_mac_policy_extensions_t, px_args->mac_extensions_size, M_TEMP, M_WAITOK);
+       if ((error = copyin(px_args->mac_extensions, psmx, px_args->mac_extensions_size)) != 0)
+               goto bad;
+
+       if (PS_MAC_EXTENSIONS_SIZE(psmx->psmx_count) > px_args->mac_extensions_size) {
+               error = EINVAL;
+               goto bad;
+       }
+
+       for (i = 0; i < psmx->psmx_count; i++) {
+               _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i];
+               if (extension->datalen == 0 || extension->datalen > PAGE_SIZE) {
+                       error = EINVAL;
+                       goto bad;
+               }
+       }
+
+       for (copycnt = 0; copycnt < psmx->psmx_count; copycnt++) {
+               _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[copycnt];
+               void *data = NULL;
+
+               MALLOC(data, void *, extension->datalen, M_TEMP, M_WAITOK);
+               if ((error = copyin(extension->data, data, extension->datalen)) != 0) {
+                       FREE(data, M_TEMP);
+                       goto bad;
+               }
+               extension->datap = data;
+       }
+
+       *psmxp = psmx;
+       return 0;
+
+bad:
+       if (psmx != NULL) {
+               for (i = 0; i < copycnt; i++)
+                       FREE(psmx->psmx_extensions[i].datap, M_TEMP);
+               FREE(psmx, M_TEMP);
+       }
+       return error;
+}
+
+static void
+spawn_free_macpolicyinfo(_posix_spawn_mac_policy_extensions_t psmx)
+{
+       int i;
+
+       if (psmx == NULL)
+               return;
+       for (i = 0; i < psmx->psmx_count; i++)
+               FREE(psmx->psmx_extensions[i].datap, M_TEMP);
+       FREE(psmx, M_TEMP);
+}
+#endif /* CONFIG_MACF */
+
+/*
+ * posix_spawn
+ *
+ * Parameters: uap->pid                Pointer to pid return area
+ *             uap->fname              File name to exec
+ *             uap->argp               Argument list
+ *             uap->envp               Environment list
+ *
+ * Returns:    0                       Success
+ *             EINVAL                  Invalid argument
+ *             ENOTSUP                 Not supported
+ *             ENOEXEC                 Executable file format error
+ *     exec_activate_image:EINVAL      Invalid argument
+ *     exec_activate_image:EACCES      Permission denied
+ *     exec_activate_image:EINTR       Interrupted function
+ *     exec_activate_image:ENOMEM      Not enough space
+ *     exec_activate_image:EFAULT      Bad address
+ *     exec_activate_image:ENAMETOOLONG        Filename too long
+ *     exec_activate_image:ENOEXEC     Executable file format error
+ *     exec_activate_image:ETXTBSY     Text file busy [misuse of error code]
+ *     exec_activate_image:EBADEXEC    The executable is corrupt/unknown
+ *     exec_activate_image:???
+ *     mac_execve_enter:???
+ *
+ * TODO:       Expect to need __mac_posix_spawn() at some point...
+ *             Handle posix_spawnattr_t
+ *             Handle posix_spawn_file_actions_t
+ */
+int
+posix_spawn(proc_t ap, struct posix_spawn_args *uap, int32_t *retval)
+{
+       proc_t p = ap;          /* quiet bogus GCC vfork() warning */
+       user_addr_t pid = uap->pid;
+       int ival[2];            /* dummy retval for setpgid() */
+       char *bufp = NULL; 
+       struct image_params *imgp;
+       struct vnode_attr *vap;
+       struct vnode_attr *origvap;
+       struct uthread  *uthread = 0;   /* compiler complains if not set to 0*/
+       int error, sig;
+       char alt_p_comm[sizeof(p->p_comm)] = {0};       /* for PowerPC */
+       int is_64 = IS_64BIT_PROCESS(p);
+       struct vfs_context context;
+       struct user__posix_spawn_args_desc px_args;
+       struct _posix_spawnattr px_sa;
+       _posix_spawn_file_actions_t px_sfap = NULL;
+       _posix_spawn_port_actions_t px_spap = NULL;
+       struct __kern_sigaction vec;
+       boolean_t spawn_no_exec = FALSE;
+       boolean_t proc_transit_set = TRUE;
+       boolean_t exec_done = FALSE;
+       int need_portwatch = 0, portwatch_count = 0;
+       ipc_port_t * portwatch_ports = NULL;
+       vm_size_t px_sa_offset = offsetof(struct _posix_spawnattr, psa_ports); 
+
+       /*
+        * Allocate a big chunk for locals instead of using stack since these  
+        * structures are pretty big.
+        */
+       MALLOC(bufp, char *, (sizeof(*imgp) + sizeof(*vap) + sizeof(*origvap)), M_TEMP, M_WAITOK | M_ZERO);
+       imgp = (struct image_params *) bufp;
+       if (bufp == NULL) {
+               error = ENOMEM;
+               goto bad;
+       }
+       vap = (struct vnode_attr *) (bufp + sizeof(*imgp));
+       origvap = (struct vnode_attr *) (bufp + sizeof(*imgp) + sizeof(*vap));
+
+       /* Initialize the common data in the image_params structure */
+       imgp->ip_user_fname = uap->path;
+       imgp->ip_user_argv = uap->argv;
+       imgp->ip_user_envv = uap->envp;
+       imgp->ip_vattr = vap;
+       imgp->ip_origvattr = origvap;
+       imgp->ip_vfs_context = &context;
+       imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT : IMGPF_NONE);
+       imgp->ip_p_comm = alt_p_comm;           /* for PowerPC */
+       imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32);
+
+       if (uap->adesc != USER_ADDR_NULL) {
+               if(is_64) {
+                       error = copyin(uap->adesc, &px_args, sizeof(px_args));
+               } else {
+                       struct user32__posix_spawn_args_desc px_args32;
+
+                       error = copyin(uap->adesc, &px_args32, sizeof(px_args32));
+
+                       /*
+                        * Convert arguments descriptor from external 32 bit
+                        * representation to internal 64 bit representation
+                        */
+                       px_args.attr_size = px_args32.attr_size;
+                       px_args.attrp = CAST_USER_ADDR_T(px_args32.attrp);
+                       px_args.file_actions_size = px_args32.file_actions_size;
+                       px_args.file_actions = CAST_USER_ADDR_T(px_args32.file_actions);
+                       px_args.port_actions_size = px_args32.port_actions_size;
+                       px_args.port_actions = CAST_USER_ADDR_T(px_args32.port_actions);
+                       px_args.mac_extensions_size = px_args32.mac_extensions_size;
+                       px_args.mac_extensions = CAST_USER_ADDR_T(px_args32.mac_extensions);
+               }
+               if (error)
+                       goto bad;
+
+               if (px_args.attr_size != 0) {
+                       /* 
+                        * We are not copying the port_actions pointer, 
+                        * because we already have it from px_args. 
+                        */
+                        
+
+                       if ((error = copyin(px_args.attrp, &px_sa, px_sa_offset) != 0)) 
+                       goto bad;
+               
+                       bzero( (void *)( (unsigned long) &px_sa + px_sa_offset), sizeof(px_sa) - px_sa_offset );        
+
+                       imgp->ip_px_sa = &px_sa;
+               }
+               if (px_args.file_actions_size != 0) {
+                       /* Limit file_actions to allowed number of open files */
+                       int maxfa = (p->p_limit ? p->p_rlimit[RLIMIT_NOFILE].rlim_cur : NOFILE);
+                       if (px_args.file_actions_size < PSF_ACTIONS_SIZE(1) ||
+                               px_args.file_actions_size > PSF_ACTIONS_SIZE(maxfa)) {
+                               error = EINVAL;
+                               goto bad;
+                       }
+                       MALLOC(px_sfap, _posix_spawn_file_actions_t, px_args.file_actions_size, M_TEMP, M_WAITOK);
+                       if (px_sfap == NULL) {
+                               error = ENOMEM;
+                               goto bad;
+                       }
+                       imgp->ip_px_sfa = px_sfap;
+
+                       if ((error = copyin(px_args.file_actions, px_sfap, 
+                                                       px_args.file_actions_size)) != 0)
+                               goto bad;
+
+                       /* Verify that the action count matches the struct size */
+                       if (PSF_ACTIONS_SIZE(px_sfap->psfa_act_count) != px_args.file_actions_size) {
+                               error = EINVAL;
+                               goto bad;
+                       }
+               }
+               if (px_args.port_actions_size != 0) {
+                       /* Limit port_actions to one page of data */
+                       if (px_args.port_actions_size < PS_PORT_ACTIONS_SIZE(1) ||
+                               px_args.port_actions_size > PAGE_SIZE) {
+                               error = EINVAL;
+                               goto bad;
+                       }
+
+                       MALLOC(px_spap, _posix_spawn_port_actions_t, 
+                                       px_args.port_actions_size, M_TEMP, M_WAITOK);
+                       if (px_spap == NULL) {
+                               error = ENOMEM;
+                               goto bad;
+                       }
+                       imgp->ip_px_spa = px_spap;
+
+                       if ((error = copyin(px_args.port_actions, px_spap, 
+                                                       px_args.port_actions_size)) != 0)
+                               goto bad;
+
+                       /* Verify that the action count matches the struct size */
+                       if (PS_PORT_ACTIONS_SIZE(px_spap->pspa_count) != px_args.port_actions_size) {
+                               error = EINVAL;
+                               goto bad;
+                       }
+               }
+#if CONFIG_MACF
+               if (px_args.mac_extensions_size != 0) {
+                       if ((error = spawn_copyin_macpolicyinfo(&px_args, (_posix_spawn_mac_policy_extensions_t *)&imgp->ip_px_smpx)) != 0)
+                               goto bad;
+               }
+#endif /* CONFIG_MACF */
+       }
+
+       /* set uthread to parent */
+       uthread = get_bsdthread_info(current_thread());
+
+       /*
+        * <rdar://6640530>; this does not result in a behaviour change
+        * relative to Leopard, so there should not be any existing code
+        * which depends on it.
+        */
+       if (uthread->uu_flag & UT_VFORK) {
+           error = EINVAL;
+           goto bad;
+       }
+
+       /*
+        * If we don't have the extension flag that turns "posix_spawn()"
+        * into "execve() with options", then we will be creating a new
+        * process which does not inherit memory from the parent process,
+        * which is one of the most expensive things about using fork()
+        * and execve().
+        */
+       if (imgp->ip_px_sa == NULL || !(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)){
+               if ((error = fork1(p, &imgp->ip_new_thread, PROC_CREATE_SPAWN)) != 0)
+                       goto bad;
+               imgp->ip_flags |= IMGPF_SPAWN;  /* spawn w/o exec */
+               spawn_no_exec = TRUE;           /* used in later tests */
+               DTRACE_PROC1(create, proc_t, p);
+       }
+
+       if (spawn_no_exec)
+               p = (proc_t)get_bsdthreadtask_info(imgp->ip_new_thread);
+       assert(p != NULL);
+
+       /* By default, the thread everyone plays with is the parent */
+       context.vc_thread = current_thread();
+       context.vc_ucred = p->p_ucred;  /* XXX must NOT be kauth_cred_get() */
+
+       /*
+        * However, if we're not in the setexec case, redirect the context
+        * to the newly created process instead
+        */
+       if (spawn_no_exec)
+               context.vc_thread = imgp->ip_new_thread;
+
+       /*
+        * Post fdcopy(), pre exec_handle_sugid() - this is where we want
+        * to handle the file_actions.  Since vfork() also ends up setting
+        * us into the parent process group, and saved off the signal flags,
+        * this is also where we want to handle the spawn flags.
+        */
+
+       /* Has spawn file actions? */
+       if (imgp->ip_px_sfa != NULL) {
+               /*
+                * The POSIX_SPAWN_CLOEXEC_DEFAULT flag
+                * is handled in exec_handle_file_actions().
+                */
+               if ((error = exec_handle_file_actions(imgp,
+                   imgp->ip_px_sa != NULL ? px_sa.psa_flags : 0)) != 0)
+                       goto bad;
+       }
+
+       /* Has spawn port actions? */
+       if (imgp->ip_px_spa != NULL) {
+               boolean_t is_adaptive = FALSE;
+
+               /* Will this process become adaptive? The apptype isn't ready yet, so we can't look there. */
+               if (imgp->ip_px_sa != NULL && px_sa.psa_apptype == POSIX_SPAWN_PROC_TYPE_DAEMON_ADAPTIVE)
+                       is_adaptive = TRUE;
+
+               /*
+                * portwatch only:
+                * Allocate a place to store the ports we want to bind to the new task
+                * We can't bind them until after the apptype is set.
+                */
+               if (px_spap->pspa_count != 0 && is_adaptive) {
+                       portwatch_count = px_spap->pspa_count;
+                       MALLOC(portwatch_ports, ipc_port_t *, (sizeof(ipc_port_t) * portwatch_count), M_TEMP, M_WAITOK | M_ZERO);
+               } else {
+                       portwatch_ports = NULL;
+               }
+
+               if ((error = exec_handle_port_actions(imgp,
+                   imgp->ip_px_sa != NULL ? px_sa.psa_flags : 0, &need_portwatch, portwatch_ports)) != 0) 
+                       goto bad;
+       }
+
+       /* Has spawn attr? */
+       if (imgp->ip_px_sa != NULL) {
+               /*
+                * Set the process group ID of the child process; this has
+                * to happen before the image activation.
+                */
+               if (px_sa.psa_flags & POSIX_SPAWN_SETPGROUP) {
+                       struct setpgid_args spga;
+                       spga.pid = p->p_pid;
+                       spga.pgid = px_sa.psa_pgroup;
+                       /*
+                        * Effectively, call setpgid() system call; works
+                        * because there are no pointer arguments.
+                        */
+                       if((error = setpgid(p, &spga, ival)) != 0)
+                               goto bad;
+               }
+
+               /*
+                * Reset UID/GID to parent's RUID/RGID; This works only
+                * because the operation occurs *after* the vfork() and
+                * before the call to exec_handle_sugid() by the image
+                * activator called from exec_activate_image().  POSIX
+                * requires that any setuid/setgid bits on the process
+                * image will take precedence over the spawn attributes
+                * (re)setting them.
+                *
+                * The use of p_ucred is safe, since we are acting on the
+                * new process, and it has no threads other than the one
+                * we are creating for it.
+                */
+               if (px_sa.psa_flags & POSIX_SPAWN_RESETIDS) {
+                       kauth_cred_t my_cred = p->p_ucred;
+                       kauth_cred_t my_new_cred = kauth_cred_setuidgid(my_cred, kauth_cred_getruid(my_cred), kauth_cred_getrgid(my_cred));
+                       if (my_new_cred != my_cred) {
+                               p->p_ucred = my_new_cred;
+                               /* update cred on proc */
+                               PROC_UPDATE_CREDS_ONPROC(p);
+                       }
+               }
+
+               /*
+                * Disable ASLR for the spawned process.
+                */
+               /*
+                * But only do so if we are not embedded; embedded allows for a
+                * boot-arg (-disable_aslr) to deal with this (which itself is
+                * only honored on DEVELOPMENT or DEBUG builds of xnu).
+                */
+               if (px_sa.psa_flags & _POSIX_SPAWN_DISABLE_ASLR)
+                       OSBitOrAtomic(P_DISABLE_ASLR, &p->p_flag);
+
+               /*
+                * Forcibly disallow execution from data pages for the spawned process
+                * even if it would otherwise be permitted by the architecture default.
+                */
+               if (px_sa.psa_flags & _POSIX_SPAWN_ALLOW_DATA_EXEC)
+                       imgp->ip_flags |= IMGPF_ALLOW_DATA_EXEC;
+       }
+
+       /*
+        * Disable ASLR during image activation.  This occurs either if the
+        * _POSIX_SPAWN_DISABLE_ASLR attribute was found above or if
+        * P_DISABLE_ASLR was inherited from the parent process.
+        */
+       if (p->p_flag & P_DISABLE_ASLR)
+               imgp->ip_flags |= IMGPF_DISABLE_ASLR;
+
+       /* 
+        * Clear transition flag so we won't hang if exec_activate_image() causes
+        * an automount (and launchd does a proc sysctl to service it).
+        *
+        * <rdar://problem/6848672>, <rdar://problem/5959568>.
+        */
+       if (spawn_no_exec) {
+               proc_transend(p, 0);
+               proc_transit_set = 0;
+       }
+
+#if MAC_SPAWN  /* XXX */
+       if (uap->mac_p != USER_ADDR_NULL) {
+               error = mac_execve_enter(uap->mac_p, imgp);
+               if (error)
+                       goto bad;
+       }
+#endif
+
+       /*
+        * Activate the image
+        */
+       error = exec_activate_image(imgp);
+
+       if (error == 0) {
+               /* process completed the exec */
+               exec_done = TRUE;
+       } else if (error == -1) {
+               /* Image not claimed by any activator? */
+               error = ENOEXEC;
+       }
+
+       /*
+        * If we have a spawn attr, and it contains signal related flags,
+        * the we need to process them in the "context" of the new child
+        * process, so we have to process it following image activation,
+        * prior to making the thread runnable in user space.  This is
+        * necessitated by some signal information being per-thread rather
+        * than per-process, and we don't have the new allocation in hand
+        * until after the image is activated.
+        */
+       if (!error && imgp->ip_px_sa != NULL) {
+               thread_t child_thread = current_thread();
+               uthread_t child_uthread = uthread;
+
+               /*
+                * If we created a new child thread, then the thread and
+                * uthread are different than the current ones; otherwise,
+                * we leave them, since we are in the exec case instead.
+                */
+               if (spawn_no_exec) {
+                       child_thread = imgp->ip_new_thread;
+                       child_uthread = get_bsdthread_info(child_thread);
+               }
+
+               /*
+                * Mask a list of signals, instead of them being unmasked, if
+                * they were unmasked in the parent; note that some signals
+                * are not maskable.
+                */
+               if (px_sa.psa_flags & POSIX_SPAWN_SETSIGMASK)
+                       child_uthread->uu_sigmask = (px_sa.psa_sigmask & ~sigcantmask);
+               /*
+                * Default a list of signals instead of ignoring them, if
+                * they were ignored in the parent.  Note that we pass
+                * spawn_no_exec to setsigvec() to indicate that we called
+                * fork1() and therefore do not need to call proc_signalstart()
+                * internally.
+                */
+               if (px_sa.psa_flags & POSIX_SPAWN_SETSIGDEF) {
+                       vec.sa_handler = SIG_DFL;
+                       vec.sa_tramp = 0;
+                       vec.sa_mask = 0;
+                       vec.sa_flags = 0;
+                       for (sig = 0; sig < NSIG; sig++)
+                               if (px_sa.psa_sigdefault & (1 << sig)) {
+                                       error = setsigvec(p, child_thread, sig + 1, &vec, spawn_no_exec);
+                       }
+               }
+
+               /*
+                * Activate the CPU usage monitor, if requested. This is done via a task-wide, per-thread CPU
+                * usage limit, which will generate a resource exceeded exception if any one thread exceeds the
+                * limit.
+                *
+                * Userland gives us interval in seconds, and the kernel SPI expects nanoseconds.
+                */
+               if (px_sa.psa_cpumonitor_percent != 0) {
+                       /*
+                        * Always treat a CPU monitor activation coming from spawn as entitled. Requiring
+                        * an entitlement to configure the monitor a certain way seems silly, since
+                        * whomever is turning it on could just as easily choose not to do so.
+                        *
+                        * XXX - Ignore the parameters that we get from userland. The spawnattr method of
+                        * activating the monitor always gets the system default parameters. Once we have
+                        * an explicit spawn SPI for configuring the defaults, we can revert this to
+                        * respect the params passed in from userland.
+                        */
+                       error = proc_set_task_ruse_cpu(p->task,
+                                       TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_EXC,
+                                       PROC_POLICY_CPUMON_DEFAULTS, 0,
+                                       0, TRUE);
+               }
+       }
+
+bad:
+
+       if (portwatch_ports != NULL) {
+               int needboost = 0;
+
+               /*
+                * Mark the ports as destined to be handed off to the new task, and
+                * transfer any boosts to the new task.
+                * We need to release the rights even if the posix_spawn has failed.
+                */
+               if (need_portwatch != 0) {
+                       for (int i = 0; i < portwatch_count; i++) {
+                               ipc_port_t port = NULL;
+                               
+                               if ((port = portwatch_ports[i]) != NULL) {
+                                       int boost = 0;
+                                       if (error == 0)
+                                               task_add_importance_watchport(p->task, p->p_pid, port, &boost);
+                                       ipc_port_release_send(port);
+                                       needboost += boost;
+                               }
+                       }
+               }
+
+               if (needboost != 0) {                   
+                       /*
+                        * Apply the boost count found on the ports, which will keep the
+                        * newly created process out of background until it handles the incoming messages.
+                        */
+                       task_hold_multiple_assertion(p->task, needboost);
+               }
+
+               FREE(portwatch_ports, M_TEMP);
+               portwatch_ports = NULL;
+               portwatch_count = 0;
+       }
+
+       if (error == 0) {
+               /* reset delay idle sleep status if set */
+               if ((p->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP)
+                       OSBitAndAtomic(~((uint32_t)P_DELAYIDLESLEEP), &p->p_flag);
+               /* upon  successful spawn, re/set the proc control state */
+               if (imgp->ip_px_sa != NULL) {
+                       switch (px_sa.psa_pcontrol) {
+                               case POSIX_SPAWN_PCONTROL_THROTTLE:
+                                       p->p_pcaction = P_PCTHROTTLE;
+                                       break;
+                               case POSIX_SPAWN_PCONTROL_SUSPEND:
+                                       p->p_pcaction = P_PCSUSP;
+                                       break;
+                               case POSIX_SPAWN_PCONTROL_KILL:
+                                       p->p_pcaction = P_PCKILL;
+                                       break;
+                               case POSIX_SPAWN_PCONTROL_NONE:
+                               default:
+                                       p->p_pcaction = 0;
+                                       break;
+                       };
+               }
+               exec_resettextvp(p, imgp);
+               
+#if CONFIG_MEMORYSTATUS && CONFIG_JETSAM
+               /* Has jetsam attributes? */
+               if (imgp->ip_px_sa != NULL && (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_SET)) {
+                       memorystatus_update(p, px_sa.psa_priority, 0, (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_USE_EFFECTIVE_PRIORITY),
+                           TRUE, px_sa.psa_high_water_mark, (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND));
+               }
+#endif
+       }
+
+       /*
+        * If we successfully called fork1(), we always need to do this;
+        * we identify this case by noting the IMGPF_SPAWN flag.  This is
+        * because we come back from that call with signals blocked in the
+        * child, and we have to unblock them, but we want to wait until
+        * after we've performed any spawn actions.  This has to happen
+        * before check_for_signature(), which uses psignal.
+        */
+       if (spawn_no_exec) {
+               if (proc_transit_set)
+                       proc_transend(p, 0);
+
+               /*
+                * Drop the signal lock on the child which was taken on our
+                * behalf by forkproc()/cloneproc() to prevent signals being
+                * received by the child in a partially constructed state.
+                */
+               proc_signalend(p, 0);
+
+               /* flag the 'fork' has occurred */
+               proc_knote(p->p_pptr, NOTE_FORK | p->p_pid);
+               /* then flag exec has occurred */
+               /* notify only if it has not failed due to FP Key error */
+               if ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)
+                       proc_knote(p, NOTE_EXEC);
+       }
+
+       /*
+        * We have to delay operations which might throw a signal until after
+        * the signals have been unblocked; however, we want that to happen
+        * after exec_resettextvp() so that the textvp is correct when they
+        * fire.
+        */
+       if (error == 0) {
+               error = check_for_signature(p, imgp);
+
+               /*
+                * Pay for our earlier safety; deliver the delayed signals from
+                * the incomplete spawn process now that it's complete.
+                */
+               if (imgp != NULL && spawn_no_exec && (p->p_lflag & P_LTRACED)) {
+                       psignal_vfork(p, p->task, imgp->ip_new_thread, SIGTRAP);
+               }
+       }
+
+
+       if (imgp != NULL) {
+               if (imgp->ip_vp)
+                       vnode_put(imgp->ip_vp);
+               if (imgp->ip_scriptvp)
+                       vnode_put(imgp->ip_scriptvp);
+               if (imgp->ip_strings)
+                       execargs_free(imgp);
+               if (imgp->ip_px_sfa != NULL)
+                       FREE(imgp->ip_px_sfa, M_TEMP);
+               if (imgp->ip_px_spa != NULL)
+                       FREE(imgp->ip_px_spa, M_TEMP);
+               
+#if CONFIG_MACF
+               if (imgp->ip_px_smpx != NULL)
+                       spawn_free_macpolicyinfo(imgp->ip_px_smpx);
+               if (imgp->ip_execlabelp)
+                       mac_cred_label_free(imgp->ip_execlabelp);
+               if (imgp->ip_scriptlabelp)
+                       mac_vnode_label_free(imgp->ip_scriptlabelp);
+#endif
+       }
+
+#if CONFIG_DTRACE
+       if (spawn_no_exec) {
+               /*
+                * In the original DTrace reference implementation,
+                * posix_spawn() was a libc routine that just
+                * did vfork(2) then exec(2).  Thus the proc::: probes
+                * are very fork/exec oriented.  The details of this
+                * in-kernel implementation of posix_spawn() is different
+                * (while producing the same process-observable effects)
+                * particularly w.r.t. errors, and which thread/process
+                * is constructing what on behalf of whom.
+                */
+               if (error) {
+                       DTRACE_PROC1(spawn__failure, int, error);
+               } else {
+                       DTRACE_PROC(spawn__success);
+                       /*
+                        * Some DTrace scripts, e.g. newproc.d in
+                        * /usr/bin, rely on the the 'exec-success'
+                        * probe being fired in the child after the
+                        * new process image has been constructed
+                        * in order to determine the associated pid.
+                        *
+                        * So, even though the parent built the image
+                        * here, for compatibility, mark the new thread
+                        * so 'exec-success' fires on it as it leaves
+                        * the kernel.
+                        */
+                       dtrace_thread_didexec(imgp->ip_new_thread);
+               }
+       } else {
+               if (error) {
+                       DTRACE_PROC1(exec__failure, int, error);
+               } else {
+                       DTRACE_PROC(exec__success);
+               }
+       }
+#endif
+
+       /* Return to both the parent and the child? */
+       if (imgp != NULL && spawn_no_exec) {
+               /*
+                * If the parent wants the pid, copy it out
+                */
+               if (pid != USER_ADDR_NULL)
+                       (void)suword(pid, p->p_pid);
+               retval[0] = error;
+
+               /*
+                * If we had an error, perform an internal reap ; this is
+                * entirely safe, as we have a real process backing us.
+                */
+               if (error) {
+                       proc_list_lock();
+                       p->p_listflag |= P_LIST_DEADPARENT;
+                       proc_list_unlock();
+                       proc_lock(p);
+                       /* make sure no one else has killed it off... */
+                       if (p->p_stat != SZOMB && p->exit_thread == NULL) {
+                               p->exit_thread = current_thread();
+                               proc_unlock(p);
+                               exit1(p, 1, (int *)NULL);
+                               if (exec_done == FALSE) {
+                                       task_deallocate(get_threadtask(imgp->ip_new_thread));
+                                       thread_deallocate(imgp->ip_new_thread);
+                               }
+                       } else {
+                               /* someone is doing it for us; just skip it */
+                               proc_unlock(p);
+                       }
+               } else {
+
+                       /*
+                        * Return to the child
+                        *
+                        * Note: the image activator earlier dropped the
+                        * task/thread references to the newly spawned
+                        * process; this is OK, since we still have suspended
+                        * queue references on them, so we should be fine
+                        * with the delayed resume of the thread here.
+                        */
+                       (void)thread_resume(imgp->ip_new_thread);
+               }
+       }
+       if (bufp != NULL) {
+               FREE(bufp, M_TEMP);
+       }
+       
+       return(error);
+}
+
+
+/*
+ * execve
+ *
+ * Parameters: uap->fname              File name to exec
+ *             uap->argp               Argument list
+ *             uap->envp               Environment list
+ *
+ * Returns:    0                       Success
+ *     __mac_execve:EINVAL             Invalid argument
+ *     __mac_execve:ENOTSUP            Invalid argument
+ *     __mac_execve:EACCES             Permission denied
+ *     __mac_execve:EINTR              Interrupted function
+ *     __mac_execve:ENOMEM             Not enough space
+ *     __mac_execve:EFAULT             Bad address
+ *     __mac_execve:ENAMETOOLONG       Filename too long
+ *     __mac_execve:ENOEXEC            Executable file format error
+ *     __mac_execve:ETXTBSY            Text file busy [misuse of error code]
+ *     __mac_execve:???
+ *
+ * TODO:       Dynamic linker header address on stack is copied via suword()
+ */
+/* ARGSUSED */
+int
+execve(proc_t p, struct execve_args *uap, int32_t *retval)
+{
+       struct __mac_execve_args muap;
+       int err;
+
+       memoryshot(VM_EXECVE, DBG_FUNC_NONE);
+
+       muap.fname = uap->fname;
+       muap.argp = uap->argp;
+       muap.envp = uap->envp;
+       muap.mac_p = USER_ADDR_NULL;
+       err = __mac_execve(p, &muap, retval);
+
+       return(err);
+}
+
+/*
+ * __mac_execve
+ *
+ * Parameters: uap->fname              File name to exec
+ *             uap->argp               Argument list
+ *             uap->envp               Environment list
+ *             uap->mac_p              MAC label supplied by caller
+ *
+ * Returns:    0                       Success
+ *             EINVAL                  Invalid argument
+ *             ENOTSUP                 Not supported
+ *             ENOEXEC                 Executable file format error
+ *     exec_activate_image:EINVAL      Invalid argument
+ *     exec_activate_image:EACCES      Permission denied
+ *     exec_activate_image:EINTR       Interrupted function
+ *     exec_activate_image:ENOMEM      Not enough space
+ *     exec_activate_image:EFAULT      Bad address
+ *     exec_activate_image:ENAMETOOLONG        Filename too long
+ *     exec_activate_image:ENOEXEC     Executable file format error
+ *     exec_activate_image:ETXTBSY     Text file busy [misuse of error code]
+ *     exec_activate_image:EBADEXEC    The executable is corrupt/unknown
+ *     exec_activate_image:???
+ *     mac_execve_enter:???
+ *
+ * TODO:       Dynamic linker header address on stack is copied via suword()
+ */
+int
+__mac_execve(proc_t p, struct __mac_execve_args *uap, int32_t *retval)
+{
+       char *bufp = NULL; 
+       struct image_params *imgp;
+       struct vnode_attr *vap;
+       struct vnode_attr *origvap;
+       int error;
+       char alt_p_comm[sizeof(p->p_comm)] = {0};       /* for PowerPC */
+       int is_64 = IS_64BIT_PROCESS(p);
+       struct vfs_context context;
+
+       context.vc_thread = current_thread();
+       context.vc_ucred = kauth_cred_proc_ref(p);      /* XXX must NOT be kauth_cred_get() */
+
+       /* Allocate a big chunk for locals instead of using stack since these  
+        * structures a pretty big.
+        */
+       MALLOC(bufp, char *, (sizeof(*imgp) + sizeof(*vap) + sizeof(*origvap)), M_TEMP, M_WAITOK | M_ZERO);
+       imgp = (struct image_params *) bufp;
+       if (bufp == NULL) {
+               error = ENOMEM;
+               goto exit_with_error;
+       }
+       vap = (struct vnode_attr *) (bufp + sizeof(*imgp));
+       origvap = (struct vnode_attr *) (bufp + sizeof(*imgp) + sizeof(*vap));
+       
+       /* Initialize the common data in the image_params structure */
+       imgp->ip_user_fname = uap->fname;
+       imgp->ip_user_argv = uap->argp;
+       imgp->ip_user_envv = uap->envp;
+       imgp->ip_vattr = vap;
+       imgp->ip_origvattr = origvap;
+       imgp->ip_vfs_context = &context;
+       imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT : IMGPF_NONE) | ((p->p_flag & P_DISABLE_ASLR) ? IMGPF_DISABLE_ASLR : IMGPF_NONE);
+       imgp->ip_p_comm = alt_p_comm;           /* for PowerPC */
+       imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32);
+
+#if CONFIG_MACF
+       if (uap->mac_p != USER_ADDR_NULL) {
+               error = mac_execve_enter(uap->mac_p, imgp);
+               if (error) {
+                       kauth_cred_unref(&context.vc_ucred);
+                       goto exit_with_error;
+               }
+       }
+#endif
+
+       error = exec_activate_image(imgp);
+
+       kauth_cred_unref(&context.vc_ucred);
+       
+       /* Image not claimed by any activator? */
+       if (error == -1)
+               error = ENOEXEC;
+
+       if (error == 0) {
+               exec_resettextvp(p, imgp);
+               error = check_for_signature(p, imgp);
+       }       
+       if (imgp->ip_vp != NULLVP)
+               vnode_put(imgp->ip_vp);
+       if (imgp->ip_scriptvp != NULLVP)
+               vnode_put(imgp->ip_scriptvp);
+       if (imgp->ip_strings)
+               execargs_free(imgp);
+#if CONFIG_MACF
+       if (imgp->ip_execlabelp)
+               mac_cred_label_free(imgp->ip_execlabelp);
+       if (imgp->ip_scriptlabelp)
+               mac_vnode_label_free(imgp->ip_scriptlabelp);
+#endif
+       if (!error) {
+               struct uthread  *uthread;
+
+               /* Sever any extant thread affinity */
+               thread_affinity_exec(current_thread());
+
+               DTRACE_PROC(exec__success);
+               uthread = get_bsdthread_info(current_thread());
+               if (uthread->uu_flag & UT_VFORK) {
+                       vfork_return(p, retval, p->p_pid);
+                       (void)thread_resume(imgp->ip_new_thread);
+               }
+       } else {
+               DTRACE_PROC1(exec__failure, int, error);
+       }
+
+exit_with_error:
+       if (bufp != NULL) {
+               FREE(bufp, M_TEMP);
+       }
+       
+       return(error);
+}
+
+
+/*
+ * copyinptr
+ *
+ * Description:        Copy a pointer in from user space to a user_addr_t in kernel
+ *             space, based on 32/64 bitness of the user space
+ *
+ * Parameters: froma                   User space address
+ *             toptr                   Address of kernel space user_addr_t
+ *             ptr_size                4/8, based on 'froma' address space
+ *
+ * Returns:    0                       Success
+ *             EFAULT                  Bad 'froma'
+ *
+ * Implicit returns:
+ *             *ptr_size               Modified
+ */
+static int
+copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size)
+{
+       int error;
+
+       if (ptr_size == 4) {
+               /* 64 bit value containing 32 bit address */
+               unsigned int i;
+
+               error = copyin(froma, &i, 4);
+               *toptr = CAST_USER_ADDR_T(i);   /* SAFE */
+       } else {
+               error = copyin(froma, toptr, 8);
+       }
+       return (error);
+}
+
+
+/*
+ * copyoutptr
+ *
+ * Description:        Copy a pointer out from a user_addr_t in kernel space to
+ *             user space, based on 32/64 bitness of the user space
+ *
+ * Parameters: ua                      User space address to copy to
+ *             ptr                     Address of kernel space user_addr_t
+ *             ptr_size                4/8, based on 'ua' address space
+ *
+ * Returns:    0                       Success
+ *             EFAULT                  Bad 'ua'
+ *
+ */
+static int
+copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size)
+{
+       int error;
+
+       if (ptr_size == 4) {
+               /* 64 bit value containing 32 bit address */
+               unsigned int i = CAST_DOWN_EXPLICIT(unsigned int,ua);   /* SAFE */
+
+               error = copyout(&i, ptr, 4);
+       } else {
+               error = copyout(&ua, ptr, 8);
+       }
+       return (error);
+}
+
+
+/*
+ * exec_copyout_strings
+ *
+ * Copy out the strings segment to user space.  The strings segment is put
+ * on a preinitialized stack frame.
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *             int *                   a pointer to the stack offset variable
+ *
+ * Returns:    0                       Success
+ *             !0                      Faiure: errno
+ *
+ * Implicit returns:
+ *             (*stackp)               The stack offset, modified
+ *
+ * Note:       The strings segment layout is backward, from the beginning
+ *             of the top of the stack to consume the minimal amount of
+ *             space possible; the returned stack pointer points to the
+ *             end of the area consumed (stacks grow downward).
+ *
+ *             argc is an int; arg[i] are pointers; env[i] are pointers;
+ *             the 0's are (void *)NULL's
+ *
+ * The stack frame layout is:
+ *
+ *      +-------------+ <- p->user_stack
+ *      |     16b     |
+ *      +-------------+
+ *      | STRING AREA |
+ *      |      :      |
+ *      |      :      |
+ *      |      :      |
+ *      +- -- -- -- --+
+ *      |  PATH AREA  |
+ *      +-------------+
+ *      |      0      |
+ *      +-------------+
+ *      |  applev[n]  |
+ *      +-------------+
+ *             :
+ *             :
+ *      +-------------+
+ *      |  applev[1]  |
+ *      +-------------+
+ *      | exec_path / |
+ *      |  applev[0]  |
+ *      +-------------+
+ *      |      0      |
+ *      +-------------+
+ *      |    env[n]   |
+ *      +-------------+
+ *             :
+ *             :
+ *      +-------------+
+ *      |    env[0]   |
+ *      +-------------+
+ *      |      0      |
+ *      +-------------+
+ *      | arg[argc-1] |
+ *      +-------------+
+ *             :
+ *             :
+ *      +-------------+
+ *      |    arg[0]   |
+ *      +-------------+
+ *      |     argc    |
+ * sp-> +-------------+
+ *
+ * Although technically a part of the STRING AREA, we treat the PATH AREA as
+ * a separate entity.  This allows us to align the beginning of the PATH AREA
+ * to a pointer boundary so that the exec_path, env[i], and argv[i] pointers
+ * which preceed it on the stack are properly aligned.
+ */
+
+static int
+exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
+{
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
+       int     ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4;
+       int     ptr_area_size;
+       void *ptr_buffer_start, *ptr_buffer;
+       int string_size;
+
+       user_addr_t     string_area;    /* *argv[], *env[] */
+       user_addr_t     ptr_area;       /* argv[], env[], applev[] */
+       user_addr_t argc_area;  /* argc */
+       user_addr_t     stack;
+       int error;
+
+       unsigned i;
+       struct copyout_desc {
+               char    *start_string;
+               int             count;
+#if CONFIG_DTRACE
+               user_addr_t     *dtrace_cookie;
+#endif
+               boolean_t       null_term;
+       } descriptors[] = {
+               {
+                       .start_string = imgp->ip_startargv,
+                       .count = imgp->ip_argc,
+#if CONFIG_DTRACE
+                       .dtrace_cookie = &p->p_dtrace_argv,
+#endif
+                       .null_term = TRUE
+               },
+               {
+                       .start_string = imgp->ip_endargv,
+                       .count = imgp->ip_envc,
+#if CONFIG_DTRACE
+                       .dtrace_cookie = &p->p_dtrace_envp,
+#endif
+                       .null_term = TRUE
+               },
+               {
+                       .start_string = imgp->ip_strings,
+                       .count = 1,
+#if CONFIG_DTRACE
+                       .dtrace_cookie = NULL,
+#endif
+                       .null_term = FALSE
+               },
+               {
+                       .start_string = imgp->ip_endenvv,
+                       .count = imgp->ip_applec - 1, /* exec_path handled above */
+#if CONFIG_DTRACE
+                       .dtrace_cookie = NULL,
+#endif
+                       .null_term = TRUE
+               }
+       };
+
+       stack = *stackp;
+
+       /*
+        * All previous contributors to the string area
+        * should have aligned their sub-area
+        */
+       if (imgp->ip_strspace % ptr_size != 0) {
+               error = EINVAL;
+               goto bad;
+       }
+
+       /* Grow the stack down for the strings we've been building up */
+       string_size = imgp->ip_strendp - imgp->ip_strings;
+       stack -= string_size;
+       string_area = stack;
+
+       /*
+        * Need room for one pointer for each string, plus
+        * one for the NULLs terminating the argv, envv, and apple areas.
+        */
+       ptr_area_size = (imgp->ip_argc + imgp->ip_envc + imgp->ip_applec + 3) *
+           ptr_size;
+       stack -= ptr_area_size;
+       ptr_area = stack;
+
+       /* We'll construct all the pointer arrays in our string buffer,
+        * which we already know is aligned properly, and ip_argspace
+        * was used to verify we have enough space.
+        */
+       ptr_buffer_start = ptr_buffer = (void *)imgp->ip_strendp;
+
+       /*
+        * Need room for pointer-aligned argc slot.
+        */
+       stack -= ptr_size;
+       argc_area = stack;
+
+       /*
+        * Record the size of the arguments area so that sysctl_procargs()
+        * can return the argument area without having to parse the arguments.
+        */
+       proc_lock(p);
+       p->p_argc = imgp->ip_argc;
+       p->p_argslen = (int)(*stackp - string_area);
+       proc_unlock(p);
+
+       /* Return the initial stack address: the location of argc */
+       *stackp = stack;
+
+       /*
+        * Copy out the entire strings area.
+        */
+       error = copyout(imgp->ip_strings, string_area,
+                                                  string_size);
+       if (error)
+               goto bad;
+
+       for (i = 0; i < sizeof(descriptors)/sizeof(descriptors[0]); i++) {
+               char *cur_string = descriptors[i].start_string;
+               int j;
+
+#if CONFIG_DTRACE
+               if (descriptors[i].dtrace_cookie) {
+                       proc_lock(p);
+                       *descriptors[i].dtrace_cookie = ptr_area + ((uintptr_t)ptr_buffer - (uintptr_t)ptr_buffer_start); /* dtrace convenience */
+                       proc_unlock(p);
+               }
+#endif /* CONFIG_DTRACE */
+
+               /*
+                * For each segment (argv, envv, applev), copy as many pointers as requested
+                * to our pointer buffer.
+                */
+               for (j = 0; j < descriptors[i].count; j++) {
+                       user_addr_t cur_address = string_area + (cur_string - imgp->ip_strings);
+                       
+                       /* Copy out the pointer to the current string. Alignment has been verified  */
+                       if (ptr_size == 8) {
+                               *(uint64_t *)ptr_buffer = (uint64_t)cur_address;
+                       } else {
+                               *(uint32_t *)ptr_buffer = (uint32_t)cur_address;
+                       }
+                       
+                       ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size);
+                       cur_string += strlen(cur_string) + 1; /* Only a NUL between strings in the same area */
+               }
+
+               if (descriptors[i].null_term) {
+                       if (ptr_size == 8) {
+                               *(uint64_t *)ptr_buffer = 0ULL;
+                       } else {
+                               *(uint32_t *)ptr_buffer = 0;
+                       }
+                       
+                       ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size);
+               }
+       }
+
+       /*
+        * Copy out all our pointer arrays in bulk.
+        */
+       error = copyout(ptr_buffer_start, ptr_area,
+                                       ptr_area_size);
+       if (error)
+               goto bad;
+
+       /* argc (int32, stored in a ptr_size area) */
+       error = copyoutptr((user_addr_t)imgp->ip_argc, argc_area, ptr_size);
+       if (error)
+               goto bad;
+
+bad:
+       return(error);
+}
+
+
+/*
+ * exec_extract_strings
+ *
+ * Copy arguments and environment from user space into work area; we may
+ * have already copied some early arguments into the work area, and if
+ * so, any arguments opied in are appended to those already there.
+ * This function is the primary manipulator of ip_argspace, since
+ * these are the arguments the client of execve(2) knows about. After
+ * each argv[]/envv[] string is copied, we charge the string length
+ * and argv[]/envv[] pointer slot to ip_argspace, so that we can
+ * full preflight the arg list size.
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *
+ * Returns:    0                       Success
+ *             !0                      Failure: errno
+ *
+ * Implicit returns;
+ *             (imgp->ip_argc)         Count of arguments, updated
+ *             (imgp->ip_envc)         Count of environment strings, updated
+ *             (imgp->ip_argspace)     Count of remaining of NCARGS
+ *             (imgp->ip_interp_buffer)        Interpreter and args (mutated in place)
+ *
+ *
+ * Note:       The argument and environment vectors are user space pointers
+ *             to arrays of user space pointers.
+ */
+static int
+exec_extract_strings(struct image_params *imgp)
+{
+       int error = 0;
+       int     ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT) ? 8 : 4;
+       int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4;
+       user_addr_t     argv = imgp->ip_user_argv;
+       user_addr_t     envv = imgp->ip_user_envv;
+
+       /*
+        * Adjust space reserved for the path name by however much padding it
+        * needs. Doing this here since we didn't know if this would be a 32- 
+        * or 64-bit process back in exec_save_path.
+        */
+       while (imgp->ip_strspace % new_ptr_size != 0) {
+               *imgp->ip_strendp++ = '\0';
+               imgp->ip_strspace--;
+               /* imgp->ip_argspace--; not counted towards exec args total */
+       }
+
+       /*
+        * From now on, we start attributing string space to ip_argspace
+        */
+       imgp->ip_startargv = imgp->ip_strendp;
+       imgp->ip_argc = 0;
+
+       if((imgp->ip_flags & IMGPF_INTERPRET) != 0) {
+               user_addr_t     arg;
+               char *argstart, *ch;
+
+               /* First, the arguments in the "#!" string are tokenized and extracted. */
+               argstart = imgp->ip_interp_buffer;
+               while (argstart) {
+                       ch = argstart;
+                       while (*ch && !IS_WHITESPACE(*ch)) {
+                               ch++;
+                       }
+
+                       if (*ch == '\0') {
+                               /* last argument, no need to NUL-terminate */
+                               error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE);
+                               argstart = NULL;
+                       } else {
+                               /* NUL-terminate */
+                               *ch = '\0';
+                               error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE);
+
+                               /*
+                                * Find the next string. We know spaces at the end of the string have already
+                                * been stripped.
+                                */
+                               argstart = ch + 1;
+                               while (IS_WHITESPACE(*argstart)) {
+                                       argstart++;
+                               }
+                       }
+
+                       /* Error-check, regardless of whether this is the last interpreter arg or not */
+                       if (error)
+                               goto bad;
+                       if (imgp->ip_argspace < new_ptr_size) {
+                               error = E2BIG;
+                               goto bad;
+                       }
+                       imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
+                       imgp->ip_argc++;
+               }
+
+               if (argv != 0LL) {
+                       /*
+                        * If we are running an interpreter, replace the av[0] that was
+                        * passed to execve() with the path name that was
+                        * passed to execve() for interpreters which do not use the PATH
+                        * to locate their script arguments.
+                        */
+                       error = copyinptr(argv, &arg, ptr_size);
+                       if (error)
+                               goto bad;
+                       if (arg != 0LL) {
+                               argv += ptr_size; /* consume without using */
+                       }
+               }
+
+               if (imgp->ip_interp_sugid_fd != -1) {
+                       char temp[19]; /* "/dev/fd/" + 10 digits + NUL */
+                       snprintf(temp, sizeof(temp), "/dev/fd/%d", imgp->ip_interp_sugid_fd);
+                       error = exec_add_user_string(imgp, CAST_USER_ADDR_T(temp), UIO_SYSSPACE, TRUE);
+               } else {
+                       error = exec_add_user_string(imgp, imgp->ip_user_fname, imgp->ip_seg, TRUE);
+               }
+               
+               if (error)
+                       goto bad;
+               if (imgp->ip_argspace < new_ptr_size) {
+                       error = E2BIG;
+                       goto bad;
+               }
+               imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
+               imgp->ip_argc++;
+       }
+
+       while (argv != 0LL) {
+               user_addr_t     arg;
+
+               error = copyinptr(argv, &arg, ptr_size);
+               if (error)
+                       goto bad;
+
+               if (arg == 0LL) {
+                       break;
+               }
+
+               argv += ptr_size;
+
+               /*
+               * av[n...] = arg[n]
+               */
+               error = exec_add_user_string(imgp, arg, imgp->ip_seg, TRUE);
+               if (error)
+                       goto bad;
+               if (imgp->ip_argspace < new_ptr_size) {
+                       error = E2BIG;
+                       goto bad;
+               }
+               imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
+               imgp->ip_argc++;
+       }        
+
+       /* Save space for argv[] NULL terminator */
+       if (imgp->ip_argspace < new_ptr_size) {
+               error = E2BIG;
+               goto bad;
+       }
+       imgp->ip_argspace -= new_ptr_size;
+       
+       /* Note where the args ends and env begins. */
+       imgp->ip_endargv = imgp->ip_strendp;
+       imgp->ip_envc = 0;
+
+       /* Now, get the environment */
+       while (envv != 0LL) {
+               user_addr_t     env;
+
+               error = copyinptr(envv, &env, ptr_size);
+               if (error)
+                       goto bad;
+
+               envv += ptr_size;
+               if (env == 0LL) {
+                       break;
+               }
+               /*
+               * av[n...] = env[n]
+               */
+               error = exec_add_user_string(imgp, env, imgp->ip_seg, TRUE);
+               if (error)
+                       goto bad;
+               if (imgp->ip_argspace < new_ptr_size) {
+                       error = E2BIG;
+                       goto bad;
+               }
+               imgp->ip_argspace -= new_ptr_size; /* to hold envv[] entry */
+               imgp->ip_envc++;
+       }
+
+       /* Save space for envv[] NULL terminator */
+       if (imgp->ip_argspace < new_ptr_size) {
+               error = E2BIG;
+               goto bad;
+       }
+       imgp->ip_argspace -= new_ptr_size;
+
+       /* Align the tail of the combined argv+envv area */
+       while (imgp->ip_strspace % new_ptr_size != 0) {
+               if (imgp->ip_argspace < 1) {
+                       error = E2BIG;
+                       goto bad;
+               }
+               *imgp->ip_strendp++ = '\0';
+               imgp->ip_strspace--;
+               imgp->ip_argspace--;
+       }
+       
+       /* Note where the envv ends and applev begins. */
+       imgp->ip_endenvv = imgp->ip_strendp;
+
+       /*
+        * From now on, we are no longer charging argument
+        * space to ip_argspace.
+        */
+
+bad:
+       return error;
+}
+
+static char *
+random_hex_str(char *str, int len, boolean_t embedNUL)
+{
+       uint64_t low, high, value;
+       int idx;
+       char digit;
+
+       /* A 64-bit value will only take 16 characters, plus '0x' and NULL. */
+       if (len > 19)
+               len = 19;
+
+       /* We need enough room for at least 1 digit */
+       if (len < 4)
+               return (NULL);
+
+       low = random();
+       high = random();
+       value = high << 32 | low;
+
+       if (embedNUL) {
+               /*
+                * Zero a byte to protect against C string vulnerabilities
+                * e.g. for userland __stack_chk_guard.
+                */ 
+               value &= ~(0xffull << 8);
+       }
+
+       str[0] = '0';
+       str[1] = 'x';
+       for (idx = 2; idx < len - 1; idx++) {
+               digit = value & 0xf;
+               value = value >> 4;
+               if (digit < 10)
+                       str[idx] = '0' + digit;
+               else
+                       str[idx] = 'a' + (digit - 10);
+       }
+       str[idx] = '\0';
+       return (str);
+}
+
+/*
+ * Libc has an 8-element array set up for stack guard values.  It only fills
+ * in one of those entries, and both gcc and llvm seem to use only a single
+ * 8-byte guard.  Until somebody needs more than an 8-byte guard value, don't
+ * do the work to construct them.
+ */
+#define        GUARD_VALUES 1
+#define        GUARD_KEY "stack_guard="
+
+/*
+ * System malloc needs some entropy when it is initialized.
+ */
+#define        ENTROPY_VALUES 2
+#define ENTROPY_KEY "malloc_entropy="
+
+/*
+ * System malloc engages nanozone for UIAPP.
+ */
+#define NANO_ENGAGE_KEY "MallocNanoZone=1"
+
+#define PFZ_KEY "pfz="
+extern user32_addr_t commpage_text32_location;
+extern user64_addr_t commpage_text64_location;
+/*
+ * Build up the contents of the apple[] string vector
+ */
+static int
+exec_add_apple_strings(struct image_params *imgp)
+{
+       int i, error;
+       int new_ptr_size=4;
+       char guard[19];
+       char guard_vec[strlen(GUARD_KEY) + 19 * GUARD_VALUES + 1];
+
+       char entropy[19];
+       char entropy_vec[strlen(ENTROPY_KEY) + 19 * ENTROPY_VALUES + 1];
+
+       char pfz_string[strlen(PFZ_KEY) + 16 + 4 +1];
+       
+       if( imgp->ip_flags & IMGPF_IS_64BIT) {
+               new_ptr_size = 8;
+               snprintf(pfz_string, sizeof(pfz_string),PFZ_KEY "0x%llx",commpage_text64_location);
+       } else {
+               snprintf(pfz_string, sizeof(pfz_string),PFZ_KEY "0x%x",commpage_text32_location);
+       }
+
+       /* exec_save_path stored the first string */
+       imgp->ip_applec = 1;
+
+       /* adding the pfz string */
+       error = exec_add_user_string(imgp, CAST_USER_ADDR_T(pfz_string),UIO_SYSSPACE,FALSE);
+       if(error)
+               goto bad;
+       imgp->ip_applec++;
+
+       /* adding the NANO_ENGAGE_KEY key */
+       if (imgp->ip_px_sa) {
+           int proc_type = (((struct _posix_spawnattr *) imgp->ip_px_sa)->psa_apptype) & POSIX_SPAWN_PROC_TYPE_MASK;
+
+           if (proc_type == POSIX_SPAWN_PROC_TYPE_APP_DEFAULT || proc_type == POSIX_SPAWN_PROC_TYPE_APP_TAL) {
+               char uiapp_string[strlen(NANO_ENGAGE_KEY) + 1];
+
+               snprintf(uiapp_string, sizeof(uiapp_string), NANO_ENGAGE_KEY);
+               error = exec_add_user_string(imgp, CAST_USER_ADDR_T(uiapp_string),UIO_SYSSPACE,FALSE);
+               if(error)
+                       goto bad;
+               imgp->ip_applec++;
+           }
+       }
+
+       /*
+        * Supply libc with a collection of random values to use when
+        * implementing -fstack-protector.
+        *
+        * (The first random string always contains an embedded NUL so that
+        * __stack_chk_guard also protects against C string vulnerabilities)
+        */
+       (void)strlcpy(guard_vec, GUARD_KEY, sizeof (guard_vec));
+       for (i = 0; i < GUARD_VALUES; i++) {
+               random_hex_str(guard, sizeof (guard), i == 0);
+               if (i)
+                       (void)strlcat(guard_vec, ",", sizeof (guard_vec));
+               (void)strlcat(guard_vec, guard, sizeof (guard_vec));
+       }
+
+       error = exec_add_user_string(imgp, CAST_USER_ADDR_T(guard_vec), UIO_SYSSPACE, FALSE);
+       if (error)
+               goto bad;
+       imgp->ip_applec++;
+
+       /*
+        * Supply libc with entropy for system malloc.
+        */
+       (void)strlcpy(entropy_vec, ENTROPY_KEY, sizeof(entropy_vec));
+       for (i = 0; i < ENTROPY_VALUES; i++) {
+               random_hex_str(entropy, sizeof (entropy), FALSE);
+               if (i)
+                       (void)strlcat(entropy_vec, ",", sizeof (entropy_vec));
+               (void)strlcat(entropy_vec, entropy, sizeof (entropy_vec));
+       }
+       
+       error = exec_add_user_string(imgp, CAST_USER_ADDR_T(entropy_vec), UIO_SYSSPACE, FALSE);
+       if (error)
+               goto bad;
+       imgp->ip_applec++;
+
+       /* Align the tail of the combined applev area */
+       while (imgp->ip_strspace % new_ptr_size != 0) {
+               *imgp->ip_strendp++ = '\0';
+               imgp->ip_strspace--;
+       }
+
+bad:
+       return error;
+}
+
+#define        unix_stack_size(p)      (p->p_rlimit[RLIMIT_STACK].rlim_cur)
+
+/*
+ * exec_check_permissions
+ *
+ * Description:        Verify that the file that is being attempted to be executed
+ *             is in fact allowed to be executed based on it POSIX file
+ *             permissions and other access control criteria
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *
+ * Returns:    0                       Success
+ *             EACCES                  Permission denied
+ *             ENOEXEC                 Executable file format error
+ *             ETXTBSY                 Text file busy [misuse of error code]
+ *     vnode_getattr:???
+ *     vnode_authorize:???
+ */
+static int
+exec_check_permissions(struct image_params *imgp)
+{
+       struct vnode *vp = imgp->ip_vp;
+       struct vnode_attr *vap = imgp->ip_vattr;
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
+       int error;
+       kauth_action_t action;
+
+       /* Only allow execution of regular files */
+       if (!vnode_isreg(vp))
+               return (EACCES);
+       
+       /* Get the file attributes that we will be using here and elsewhere */
+       VATTR_INIT(vap);
+       VATTR_WANTED(vap, va_uid);
+       VATTR_WANTED(vap, va_gid);
+       VATTR_WANTED(vap, va_mode);
+       VATTR_WANTED(vap, va_fsid);
+       VATTR_WANTED(vap, va_fileid);
+       VATTR_WANTED(vap, va_data_size);
+       if ((error = vnode_getattr(vp, vap, imgp->ip_vfs_context)) != 0)
+               return (error);
+
+       /*
+        * Ensure that at least one execute bit is on - otherwise root
+        * will always succeed, and we don't want to happen unless the
+        * file really is executable.
+        */
+       if (!vfs_authopaque(vnode_mount(vp)) && ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0))
+               return (EACCES);
+
+       /* Disallow zero length files */
+       if (vap->va_data_size == 0)
+               return (ENOEXEC);
+
+       imgp->ip_arch_offset = (user_size_t)0;
+       imgp->ip_arch_size = vap->va_data_size;
+
+       /* Disable setuid-ness for traced programs or if MNT_NOSUID */
+       if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_lflag & P_LTRACED))
+               vap->va_mode &= ~(VSUID | VSGID);
+
+       /*
+        * Disable _POSIX_SPAWN_ALLOW_DATA_EXEC and _POSIX_SPAWN_DISABLE_ASLR
+        * flags for setuid/setgid binaries.
+        */
+       if (vap->va_mode & (VSUID | VSGID))
+               imgp->ip_flags &= ~(IMGPF_ALLOW_DATA_EXEC | IMGPF_DISABLE_ASLR);
+
+#if CONFIG_MACF
+       error = mac_vnode_check_exec(imgp->ip_vfs_context, vp, imgp);
+       if (error)
+               return (error);
+#endif
+
+       /* Check for execute permission */
+       action = KAUTH_VNODE_EXECUTE;
+       /* Traced images must also be readable */
+       if (p->p_lflag & P_LTRACED)
+               action |= KAUTH_VNODE_READ_DATA;
+       if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0)
+               return (error);
+
+#if 0
+       /* Don't let it run if anyone had it open for writing */
+       vnode_lock(vp);
+       if (vp->v_writecount) {
+               panic("going to return ETXTBSY %x", vp);
+               vnode_unlock(vp);
+               return (ETXTBSY);
+       }
+       vnode_unlock(vp);
+#endif
+
+
+       /* XXX May want to indicate to underlying FS that vnode is open */
+
+       return (error);
+}
+
+
+/*
+ * exec_handle_sugid
+ *
+ * Initially clear the P_SUGID in the process flags; if an SUGID process is
+ * exec'ing a non-SUGID image, then  this is the point of no return.
+ *
+ * If the image being activated is SUGID, then replace the credential with a
+ * copy, disable tracing (unless the tracing process is root), reset the
+ * mach task port to revoke it, set the P_SUGID bit,
+ *
+ * If the saved user and group ID will be changing, then make sure it happens
+ * to a new credential, rather than a shared one.
+ *
+ * Set the security token (this is probably obsolete, given that the token
+ * should not technically be separate from the credential itself).
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *
+ * Returns:    void                    No failure indication
+ *
+ * Implicit returns:
+ *             <process credential>    Potentially modified/replaced
+ *             <task port>             Potentially revoked
+ *             <process flags>         P_SUGID bit potentially modified
+ *             <security token>        Potentially modified
+ */
+static int
+exec_handle_sugid(struct image_params *imgp)
+{
+       kauth_cred_t            cred = vfs_context_ucred(imgp->ip_vfs_context);
+       proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
+       int                     i;
+       int                     leave_sugid_clear = 0;
+       int                     error = 0;
+#if CONFIG_MACF
+       int                     mac_transition;
+
+       /*
+        * Determine whether a call to update the MAC label will result in the
+        * credential changing.
+        *
+        * Note:        MAC policies which do not actually end up modifying
+        *              the label subsequently are strongly encouraged to
+        *              return 0 for this check, since a non-zero answer will
+        *              slow down the exec fast path for normal binaries.
+        */
+       mac_transition = mac_cred_check_label_update_execve(
+                                                       imgp->ip_vfs_context,
+                                                       imgp->ip_vp,
+                                                       imgp->ip_scriptvp,
+                                                       imgp->ip_scriptlabelp,
+                                                       imgp->ip_execlabelp,
+                                                       p,
+                                                       imgp->ip_px_smpx);
+#endif
+
+       OSBitAndAtomic(~((uint32_t)P_SUGID), &p->p_flag);
+
+       /*
+        * Order of the following is important; group checks must go last,
+        * as we use the success of the 'ismember' check combined with the
+        * failure of the explicit match to indicate that we will be setting
+        * the egid of the process even though the new process did not
+        * require VSUID/VSGID bits in order for it to set the new group as
+        * its egid.
+        *
+        * Note:        Technically, by this we are implying a call to
+        *              setegid() in the new process, rather than implying
+        *              it used its VSGID bit to set the effective group,
+        *              even though there is no code in that process to make
+        *              such a call.
+        */
+       if (((imgp->ip_origvattr->va_mode & VSUID) != 0 &&
+            kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) ||
+           ((imgp->ip_origvattr->va_mode & VSGID) != 0 &&
+                ((kauth_cred_ismember_gid(cred, imgp->ip_origvattr->va_gid, &leave_sugid_clear) || !leave_sugid_clear) ||
+                (kauth_cred_getgid(cred) != imgp->ip_origvattr->va_gid)))) {
+
+#if CONFIG_MACF
+/* label for MAC transition and neither VSUID nor VSGID */
+handle_mac_transition:
+#endif
+
+               /*
+                * Replace the credential with a copy of itself if euid or
+                * egid change.
+                *
+                * Note:        setuid binaries will automatically opt out of
+                *              group resolver participation as a side effect
+                *              of this operation.  This is an intentional
+                *              part of the security model, which requires a
+                *              participating credential be established by
+                *              escalating privilege, setting up all other
+                *              aspects of the credential including whether
+                *              or not to participate in external group
+                *              membership resolution, then dropping their
+                *              effective privilege to that of the desired
+                *              final credential state.
+                */
+               if (imgp->ip_origvattr->va_mode & VSUID) {
+                       p->p_ucred  = kauth_cred_setresuid(p->p_ucred, KAUTH_UID_NONE, imgp->ip_origvattr->va_uid, imgp->ip_origvattr->va_uid, KAUTH_UID_NONE);
+                       /* update cred on proc */
+                       PROC_UPDATE_CREDS_ONPROC(p);
+               }
+               if (imgp->ip_origvattr->va_mode & VSGID) {
+                       p->p_ucred = kauth_cred_setresgid(p->p_ucred, KAUTH_GID_NONE, imgp->ip_origvattr->va_gid, imgp->ip_origvattr->va_gid);
+                       /* update cred on proc */
+                       PROC_UPDATE_CREDS_ONPROC(p);
+               }
+
+#if CONFIG_MACF
+               /* 
+                * If a policy has indicated that it will transition the label,
+                * before making the call into the MAC policies, get a new
+                * duplicate credential, so they can modify it without
+                * modifying any others sharing it.
+                */
+               if (mac_transition) { 
+                       kauth_cred_t    my_cred;
+                       if (kauth_proc_label_update_execve(p,
+                                               imgp->ip_vfs_context,
+                                               imgp->ip_vp, 
+                                               imgp->ip_scriptvp,
+                                               imgp->ip_scriptlabelp,
+                                               imgp->ip_execlabelp,
+                                               imgp->ip_px_smpx)) {
+                               /*
+                                * If updating the MAC label resulted in a
+                                * disjoint credential, flag that we need to
+                                * set the P_SUGID bit.  This protects
+                                * against debuggers being attached by an
+                                * insufficiently privileged process onto the
+                                * result of a transition to a more privileged
+                                * credential.
+                                */
+                               leave_sugid_clear = 0;
+                       }
+
+                       my_cred = kauth_cred_proc_ref(p);
+                       mac_task_label_update_cred(my_cred, p->task);
+                       kauth_cred_unref(&my_cred);
+               }
+#endif /* CONFIG_MACF */
+
+               /*
+                * If 'leave_sugid_clear' is non-zero, then we passed the
+                * VSUID and MACF checks, and successfully determined that
+                * the previous cred was a member of the VSGID group, but
+                * that it was not the default at the time of the execve,
+                * and that the post-labelling credential was not disjoint.
+                * So we don't set the P_SUGID or reset mach ports and fds 
+                * on the basis of simply running this code.
+                */
+               if (!leave_sugid_clear) {
+                       /*
+                        * Have mach reset the task and thread ports.
+                        * We don't want anyone who had the ports before
+                        * a setuid exec to be able to access/control the
+                        * task/thread after.
+                        */
+                       ipc_task_reset(p->task);
+                       ipc_thread_reset((imgp->ip_new_thread != NULL) ?
+                                        imgp->ip_new_thread : current_thread());
+
+                       /*
+                        * Flag the process as setuid.
+                        */
+                       OSBitOrAtomic(P_SUGID, &p->p_flag);
+
+                       /*
+                        * Radar 2261856; setuid security hole fix
+                        * XXX For setuid processes, attempt to ensure that
+                        * stdin, stdout, and stderr are already allocated.
+                        * We do not want userland to accidentally allocate
+                        * descriptors in this range which has implied meaning
+                        * to libc.
+                        */
+                       for (i = 0; i < 3; i++) {
+
+                               if (p->p_fd->fd_ofiles[i] != NULL)
+                                       continue;
+
+                               /*
+                                * Do the kernel equivalent of
+                                *
+                                *      if i == 0
+                                *              (void) open("/dev/null", O_RDONLY);
+                                *      else 
+                                *              (void) open("/dev/null", O_WRONLY);
+                                */
+
+                               struct fileproc *fp;
+                               int indx;
+                               int flag;
+
+                               if (i == 0)
+                                       flag = FREAD;
+                               else 
+                                       flag = FWRITE;
+
+                               if ((error = falloc(p,
+                                   &fp, &indx, imgp->ip_vfs_context)) != 0)
+                                       continue;
+
+                               struct nameidata nd1;
+
+                               NDINIT(&nd1, LOOKUP, OP_OPEN, FOLLOW, UIO_SYSSPACE,
+                                   CAST_USER_ADDR_T("/dev/null"),
+                                   imgp->ip_vfs_context);
+
+                               if ((error = vn_open(&nd1, flag, 0)) != 0) {
+                                       fp_free(p, indx, fp);
+                                       break;
+                               }
+
+                               struct fileglob *fg = fp->f_fglob;
+
+                               fg->fg_flag = flag;
+                               fg->fg_ops = &vnops;
+                               fg->fg_data = nd1.ni_vp;
+
+                               vnode_put(nd1.ni_vp);
+
+                               proc_fdlock(p);
+                               procfdtbl_releasefd(p, indx, NULL);
+                               fp_drop(p, indx, fp, 1);
+                               proc_fdunlock(p);
+                       }
+               }
+       }
+#if CONFIG_MACF
+       else {
+               /*
+                * We are here because we were told that the MAC label will
+                * be transitioned, and the binary is not VSUID or VSGID; to
+                * deal with this case, we could either duplicate a lot of
+                * code, or we can indicate we want to default the P_SUGID
+                * bit clear and jump back up.
+                */
+               if (mac_transition) {
+                       leave_sugid_clear = 1;
+                       goto handle_mac_transition;
+               }
+       }
+#endif /* CONFIG_MACF */
+
+       /*
+        * Implement the semantic where the effective user and group become
+        * the saved user and group in exec'ed programs.
+        */
+       p->p_ucred = kauth_cred_setsvuidgid(p->p_ucred, kauth_cred_getuid(p->p_ucred),  kauth_cred_getgid(p->p_ucred));
+       /* update cred on proc */
+       PROC_UPDATE_CREDS_ONPROC(p);
+       
+       /* Update the process' identity version and set the security token */
+       p->p_idversion++;
+       set_security_token(p);
+
+       return(error);
+}
+
+
+/*
+ * create_unix_stack
+ *
+ * Description:        Set the user stack address for the process to the provided
+ *             address.  If a custom stack was not set as a result of the
+ *             load process (i.e. as specified by the image file for the
+ *             executable), then allocate the stack in the provided map and
+ *             set up appropriate guard pages for enforcing administrative
+ *             limits on stack growth, if they end up being needed.
+ *
+ * Parameters: p                       Process to set stack on
+ *             load_result             Information from mach-o load commands
+ *             map                     Address map in which to allocate the new stack
+ *
+ * Returns:    KERN_SUCCESS            Stack successfully created
+ *             !KERN_SUCCESS           Mach failure code
+ */
+static kern_return_t
+create_unix_stack(vm_map_t map, load_result_t* load_result, 
+                       proc_t p)
+{
+       mach_vm_size_t          size, prot_size;
+       mach_vm_offset_t        addr, prot_addr;
+       kern_return_t           kr;
+
+       mach_vm_address_t       user_stack = load_result->user_stack;
+       
+       proc_lock(p);
+       p->user_stack = user_stack;
+       proc_unlock(p);
+
+       if (!load_result->prog_allocated_stack) {
+               /*
+                * Allocate enough space for the maximum stack size we
+                * will ever authorize and an extra page to act as
+                * a guard page for stack overflows. For default stacks,
+                * vm_initial_limit_stack takes care of the extra guard page.
+                * Otherwise we must allocate it ourselves.
+                */
+
+               size = mach_vm_round_page(load_result->user_stack_size);
+               if (load_result->prog_stack_size)
+                       size += PAGE_SIZE;
+               addr = mach_vm_trunc_page(load_result->user_stack - size);
+               kr = mach_vm_allocate(map, &addr, size,
+                                       VM_MAKE_TAG(VM_MEMORY_STACK) |
+                                       VM_FLAGS_FIXED);
+               if (kr != KERN_SUCCESS) {
+                       /* If can't allocate at default location, try anywhere */
+                       addr = 0;
+                       kr = mach_vm_allocate(map, &addr, size,
+                                                                 VM_MAKE_TAG(VM_MEMORY_STACK) |
+                                                                 VM_FLAGS_ANYWHERE);
+                       if (kr != KERN_SUCCESS)
+                               return kr;
+
+                       user_stack = addr + size;
+                       load_result->user_stack = user_stack;
+
+                       proc_lock(p);
+                       p->user_stack = user_stack;
+                       proc_unlock(p);
+               }
+
+               /*
+                * And prevent access to what's above the current stack
+                * size limit for this process.
+                */
+               prot_addr = addr;
+               if (load_result->prog_stack_size)
+                       prot_size = PAGE_SIZE;
+               else
+                       prot_size = mach_vm_trunc_page(size - unix_stack_size(p));
+               kr = mach_vm_protect(map,
+                                                        prot_addr,
+                                                        prot_size,
+                                                        FALSE,
+                                                        VM_PROT_NONE);
+               if (kr != KERN_SUCCESS) {
+                       (void) mach_vm_deallocate(map, addr, size);
+                       return kr;
+               }
+       }
+
+       return KERN_SUCCESS;
+}
+
+#include <sys/reboot.h>
+
+static char            init_program_name[128] = "/sbin/launchd";
+
+struct execve_args     init_exec_args;
+
+/*
+ * load_init_program
+ *
+ * Description:        Load the "init" program; in most cases, this will be "launchd"
+ *
+ * Parameters: p                       Process to call execve() to create
+ *                                     the "init" program
+ *
+ * Returns:    (void)
+ *
+ * Notes:      The process that is passed in is the first manufactured
+ *             process on the system, and gets here via bsd_ast() firing
+ *             for the first time.  This is done to ensure that bsd_init()
+ *             has run to completion.
+ */
+void
+load_init_program(proc_t p)
+{
+       vm_offset_t     init_addr;
+       int             argc = 0;
+       uint32_t argv[3];
+       int                     error;
+       int             retval[2];
+
+       /*
+        * Copy out program name.
+        */
+
+       init_addr = VM_MIN_ADDRESS;
+       (void) vm_allocate(current_map(), &init_addr, PAGE_SIZE,
+                               VM_FLAGS_ANYWHERE);
+       if (init_addr == 0)
+               init_addr++;
+
+       (void) copyout((caddr_t) init_program_name, CAST_USER_ADDR_T(init_addr),
+                       (unsigned) sizeof(init_program_name)+1);
+
+       argv[argc++] = (uint32_t)init_addr;
+       init_addr += sizeof(init_program_name);
+       init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
+
+       /*
+        * Put out first (and only) argument, similarly.
+        * Assumes everything fits in a page as allocated
+        * above.
+        */
+       if (boothowto & RB_SINGLE) {
+               const char *init_args = "-s";
+
+               copyout(init_args, CAST_USER_ADDR_T(init_addr),
+                       strlen(init_args));
+
+               argv[argc++] = (uint32_t)init_addr;
+               init_addr += strlen(init_args);
+               init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
+
+       }
+
+       /*
+        * Null-end the argument list
+        */
+       argv[argc] = 0;
+       
+       /*
+        * Copy out the argument list.
+        */
+       
+       (void) copyout((caddr_t) argv, CAST_USER_ADDR_T(init_addr),
+                       (unsigned) sizeof(argv));
+
+       /*
+        * Set up argument block for fake call to execve.
+        */
+
+       init_exec_args.fname = CAST_USER_ADDR_T(argv[0]);
+       init_exec_args.argp = CAST_USER_ADDR_T((char **)init_addr);
+       init_exec_args.envp = CAST_USER_ADDR_T(0);
+       
+       /*
+        * So that mach_init task is set with uid,gid 0 token 
+        */
+       set_security_token(p);
+
+       error = execve(p,&init_exec_args,retval);
+       if (error)
+               panic("Process 1 exec of %s failed, errno %d",
+                     init_program_name, error);
+}
+
+/*
+ * load_return_to_errno
+ *
+ * Description:        Convert a load_return_t (Mach error) to an errno (BSD error)
+ *
+ * Parameters: lrtn                    Mach error number
+ *
+ * Returns:    (int)                   BSD error number
+ *             0                       Success
+ *             EBADARCH                Bad architecture
+ *             EBADMACHO               Bad Mach object file
+ *             ESHLIBVERS              Bad shared library version
+ *             ENOMEM                  Out of memory/resource shortage
+ *             EACCES                  Access denied
+ *             ENOENT                  Entry not found (usually "file does
+ *                                     does not exist")
+ *             EIO                     An I/O error occurred
+ *             EBADEXEC                The executable is corrupt/unknown
+ */
+static int 
+load_return_to_errno(load_return_t lrtn)
+{
+       switch (lrtn) {
+       case LOAD_SUCCESS:
+               return 0;
+       case LOAD_BADARCH:
+               return EBADARCH;
+       case LOAD_BADMACHO:
+               return EBADMACHO;
+       case LOAD_SHLIB:
+               return ESHLIBVERS;
+       case LOAD_NOSPACE:
+       case LOAD_RESOURCE:
+               return ENOMEM;
+       case LOAD_PROTECT:
+               return EACCES;
+       case LOAD_ENOENT:
+               return ENOENT;
+       case LOAD_IOERROR:
+               return EIO;
+       case LOAD_FAILURE:
+       case LOAD_DECRYPTFAIL:
+       default:
+               return EBADEXEC;
+       }
+}
+
+#include <mach/mach_types.h>
+#include <mach/vm_prot.h>
+#include <mach/semaphore.h>
+#include <mach/sync_policy.h>
+#include <kern/clock.h>
+#include <mach/kern_return.h>
+
+/*
+ * execargs_alloc
+ *
+ * Description:        Allocate the block of memory used by the execve arguments.
+ *             At the same time, we allocate a page so that we can read in
+ *             the first page of the image.
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *
+ * Returns:    0                       Success
+ *             EINVAL                  Invalid argument
+ *             EACCES                  Permission denied
+ *             EINTR                   Interrupted function
+ *             ENOMEM                  Not enough space
+ *
+ * Notes:      This is a temporary allocation into the kernel address space
+ *             to enable us to copy arguments in from user space.  This is
+ *             necessitated by not mapping the process calling execve() into
+ *             the kernel address space during the execve() system call.
+ *
+ *             We assemble the argument and environment, etc., into this
+ *             region before copying it as a single block into the child
+ *             process address space (at the top or bottom of the stack,
+ *             depending on which way the stack grows; see the function
+ *             exec_copyout_strings() for details).
+ *
+ *             This ends up with a second (possibly unnecessary) copy compared
+ *             with assembing the data directly into the child address space,
+ *             instead, but since we cannot be guaranteed that the parent has
+ *             not modified its environment, we can't really know that it's
+ *             really a block there as well.
+ */
+
+
+static int execargs_waiters = 0;
+lck_mtx_t *execargs_cache_lock;
+
+static void
+execargs_lock_lock(void) {
+       lck_mtx_lock_spin(execargs_cache_lock);
+}
+
+static void
+execargs_lock_unlock(void) {
+       lck_mtx_unlock(execargs_cache_lock);
+}
+
+static wait_result_t
+execargs_lock_sleep(void) {
+       return(lck_mtx_sleep(execargs_cache_lock, LCK_SLEEP_DEFAULT, &execargs_free_count, THREAD_INTERRUPTIBLE));
+}
+
+static kern_return_t
+execargs_purgeable_allocate(char **execarg_address) {
+       kern_return_t kr = vm_allocate(bsd_pageable_map, (vm_offset_t *)execarg_address, BSD_PAGEABLE_SIZE_PER_EXEC, VM_FLAGS_ANYWHERE | VM_FLAGS_PURGABLE);
+       assert(kr == KERN_SUCCESS);
+       return kr;
+}
+
+static kern_return_t
+execargs_purgeable_reference(void *execarg_address) {
+       int state = VM_PURGABLE_NONVOLATILE;
+       kern_return_t kr = vm_purgable_control(bsd_pageable_map, (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state);
+
+       assert(kr == KERN_SUCCESS);
+       return kr;
+}
+
+static kern_return_t
+execargs_purgeable_volatilize(void *execarg_address) {
+       int state = VM_PURGABLE_VOLATILE | VM_PURGABLE_ORDERING_OBSOLETE;
+       kern_return_t kr;
+       kr = vm_purgable_control(bsd_pageable_map, (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state);
+
+       assert(kr == KERN_SUCCESS);
+
+       return kr;
+}
+
+static void
+execargs_wakeup_waiters(void) {
+       thread_wakeup(&execargs_free_count);
+}
+
+static int
+execargs_alloc(struct image_params *imgp)
+{
+       kern_return_t kret;
+       wait_result_t res;
+       int i, cache_index = -1;
+
+       execargs_lock_lock();
+
+       while (execargs_free_count == 0) {
+               execargs_waiters++;
+               res = execargs_lock_sleep();
+               execargs_waiters--;
+               if (res != THREAD_AWAKENED) {
+                       execargs_lock_unlock();
+                       return (EINTR);
+               }
+       }
+
+       execargs_free_count--;
+
+       for (i = 0; i < execargs_cache_size; i++) {
+               vm_offset_t element = execargs_cache[i];
+               if (element) {
+                       cache_index = i;
+                       imgp->ip_strings = (char *)(execargs_cache[i]);
+                       execargs_cache[i] = 0;
+                       break;
+               }
+       }
+
+       assert(execargs_free_count >= 0);
+
+       execargs_lock_unlock();
+       
+       if (cache_index == -1) {
+               kret = execargs_purgeable_allocate(&imgp->ip_strings);
+       }
+       else
+               kret = execargs_purgeable_reference(imgp->ip_strings);
+
+       assert(kret == KERN_SUCCESS);
+       if (kret != KERN_SUCCESS) {
+               return (ENOMEM);
+       }
+
+       /* last page used to read in file headers */
+       imgp->ip_vdata = imgp->ip_strings + ( NCARGS + PAGE_SIZE );
+       imgp->ip_strendp = imgp->ip_strings;
+       imgp->ip_argspace = NCARGS;
+       imgp->ip_strspace = ( NCARGS + PAGE_SIZE );
+
+       return (0);
+}
+
+/*
+ * execargs_free
+ *
+ * Description:        Free the block of memory used by the execve arguments and the
+ *             first page of the executable by a previous call to the function
+ *             execargs_alloc().
+ *
+ * Parameters: struct image_params *   the image parameter block
+ *
+ * Returns:    0                       Success
+ *             EINVAL                  Invalid argument
+ *             EINTR                   Oeration interrupted
+ */
+static int
+execargs_free(struct image_params *imgp)
+{
+       kern_return_t kret;
+       int i;
+       boolean_t needs_wakeup = FALSE;
+       
+       kret = execargs_purgeable_volatilize(imgp->ip_strings);
+
+       execargs_lock_lock();
+       execargs_free_count++;
+
+       for (i = 0; i < execargs_cache_size; i++) {
+               vm_offset_t element = execargs_cache[i];
+               if (element == 0) {
+                       execargs_cache[i] = (vm_offset_t) imgp->ip_strings;
+                       imgp->ip_strings = NULL;
+                       break;
+               }
+       }
+
+       assert(imgp->ip_strings == NULL);
+
+       if (execargs_waiters > 0)
+               needs_wakeup = TRUE;
+       
+       execargs_lock_unlock();
+
+       if (needs_wakeup == TRUE)
+               execargs_wakeup_waiters();
+
+       return ((kret == KERN_SUCCESS ? 0 : EINVAL));
+}
+
+static void
+exec_resettextvp(proc_t p, struct image_params *imgp)
+{
+       vnode_t vp;
+       off_t offset;
+       vnode_t tvp  = p->p_textvp;
+       int ret;
+
+       vp = imgp->ip_vp;
+       offset = imgp->ip_arch_offset;
+
+       if (vp == NULLVP)
+               panic("exec_resettextvp: expected valid vp");
+
+       ret = vnode_ref(vp);
+       proc_lock(p);
+       if (ret == 0) {
+               p->p_textvp = vp;
+               p->p_textoff = offset;
+       } else {
+               p->p_textvp = NULLVP;   /* this is paranoia */
+               p->p_textoff = 0;
+       }
+       proc_unlock(p);
+
+       if ( tvp != NULLVP) {
+               if (vnode_getwithref(tvp) == 0) {
+                       vnode_rele(tvp);
+                       vnode_put(tvp);
+               }
+       }       
+
+}
+
+/*
+ * If the process is not signed or if it contains entitlements, we
+ * need to communicate through the task_access_port to taskgated.
+ *
+ * taskgated will provide a detached code signature if present, and
+ * will enforce any restrictions on entitlements.
+ */
+
+static boolean_t
+taskgated_required(proc_t p, boolean_t *require_success)
+{
+       size_t length;
+       void *blob;
+       int error;
+
+       if ((p->p_csflags & CS_VALID) == 0) {
+               *require_success = FALSE;
+               return TRUE;
+       }
+
+       error = cs_entitlements_blob_get(p, &blob, &length);
+       if (error == 0 && blob != NULL) {
+               *require_success = TRUE; /* fatal on the desktop when entitlements are present */
+               return TRUE;
+       }
+
+       *require_success = FALSE;
+       return 0;
+}
+
+
+static int
+check_for_signature(proc_t p, struct image_params *imgp)
+{
+       mach_port_t port = NULL;
+       kern_return_t kr = KERN_FAILURE;
+       int error = EACCES;
+       boolean_t unexpected_failure = FALSE;
+       unsigned char hash[SHA1_RESULTLEN];
+       boolean_t require_success = FALSE;
+
+       /*
+        * Override inherited code signing flags with the
+        * ones for the process that is being successfully
+        * loaded
+        */
+       proc_lock(p);
+       p->p_csflags = imgp->ip_csflags;
+       proc_unlock(p);
+
+       /* Set the switch_protect flag on the map */
+       if(p->p_csflags & (CS_HARD|CS_KILL)) {
+               vm_map_switch_protect(get_task_map(p->task), TRUE);
+       }
+
+       /* check if callout to taskgated is needed */
+       if (!taskgated_required(p, &require_success)) {
+               error = 0;
+               goto done;
+       }
+
+       kr = task_get_task_access_port(p->task, &port);
+       if (KERN_SUCCESS != kr || !IPC_PORT_VALID(port)) {
+               error = 0;
+               if (require_success)
+                       error = EACCES;
+               goto done;
+       }
+
+       /*
+        * taskgated returns KERN_SUCCESS if it has completed its work
+        * and the exec should continue, KERN_FAILURE if the exec should 
+        * fail, or it may error out with different error code in an 
+        * event of mig failure (e.g. process was signalled during the 
+        * rpc call, taskgated died, mig server died etc.).
+        */
+
+       kr = find_code_signature(port, p->p_pid);
+       switch (kr) {
+       case KERN_SUCCESS:
+               error = 0;
+               break;
+       case KERN_FAILURE:
+               error = EACCES;
+               goto done;
+       default:
+               error = EACCES;
+               unexpected_failure = TRUE;
+               goto done;
+       }
+
+       /* Only do this if exec_resettextvp() did not fail */
+       if (p->p_textvp != NULLVP) {
+               /*
+                * If there's a new code directory, mark this process
+                * as signed.
+                */
+               if (0 == ubc_cs_getcdhash(p->p_textvp, p->p_textoff, hash)) {
+                       proc_lock(p);
+                       p->p_csflags |= CS_VALID;
+                       proc_unlock(p);
+               }
+       }
+
+done:
+       if (0 != error) {
+               if (!unexpected_failure)
+                       p->p_csflags |= CS_KILLED;
+               /* make very sure execution fails */
+               psignal(p, SIGKILL);
+       }
+       return error;
+}
+
+/*
+ * Typically as soon as we start executing this process, the
+ * first instruction will trigger a VM fault to bring the text
+ * pages (as executable) into the address space, followed soon
+ * thereafter by dyld data structures (for dynamic executable).
+ * To optimize this, as well as improve support for hardware
+ * debuggers that can only access resident pages present
+ * in the process' page tables, we prefault some pages if
+ * possible. Errors are non-fatal.
+ */
+static void exec_prefault_data(proc_t p __unused, struct image_params *imgp, load_result_t *load_result)
+{
+       int ret;
+       size_t expected_all_image_infos_size;
+
+       /*
+        * Prefault executable or dyld entry point.
+        */
+       vm_fault(current_map(),
+                vm_map_trunc_page(load_result->entry_point,
+                                  vm_map_page_mask(current_map())),
+                VM_PROT_READ | VM_PROT_EXECUTE,
+                FALSE,
+                THREAD_UNINT, NULL, 0);
+       
+       if (imgp->ip_flags & IMGPF_IS_64BIT) {
+               expected_all_image_infos_size = sizeof(struct user64_dyld_all_image_infos);
+       } else {
+               expected_all_image_infos_size = sizeof(struct user32_dyld_all_image_infos);
+       }
+
+       /* Decode dyld anchor structure from <mach-o/dyld_images.h> */
+       if (load_result->dynlinker &&
+               load_result->all_image_info_addr &&
+               load_result->all_image_info_size >= expected_all_image_infos_size) {
+               union {
+                       struct user64_dyld_all_image_infos      infos64;
+                       struct user32_dyld_all_image_infos      infos32;
+               } all_image_infos;
+
+               /*
+                * Pre-fault to avoid copyin() going through the trap handler
+                * and recovery path.
+                */
+               vm_fault(current_map(),
+                        vm_map_trunc_page(load_result->all_image_info_addr,
+                                          vm_map_page_mask(current_map())),
+                        VM_PROT_READ | VM_PROT_WRITE,
+                        FALSE,
+                        THREAD_UNINT, NULL, 0);
+               if ((load_result->all_image_info_addr & PAGE_MASK) + expected_all_image_infos_size > PAGE_SIZE) {
+                       /* all_image_infos straddles a page */
+                       vm_fault(current_map(),
+                                vm_map_trunc_page(load_result->all_image_info_addr + expected_all_image_infos_size - 1,
+                                                  vm_map_page_mask(current_map())),
+                                VM_PROT_READ | VM_PROT_WRITE,
+                                FALSE,
+                                THREAD_UNINT, NULL, 0);
+               }
+
+               ret = copyin(load_result->all_image_info_addr,
+                                        &all_image_infos,
+                                        expected_all_image_infos_size);
+               if (ret == 0 && all_image_infos.infos32.version >= 9) {
+
+                       user_addr_t notification_address;
+                       user_addr_t dyld_image_address;
+                       user_addr_t dyld_version_address;
+                       user_addr_t dyld_all_image_infos_address;
+                       user_addr_t dyld_slide_amount;
+
+                       if (imgp->ip_flags & IMGPF_IS_64BIT) {
+                               notification_address = all_image_infos.infos64.notification;
+                               dyld_image_address = all_image_infos.infos64.dyldImageLoadAddress;
+                               dyld_version_address = all_image_infos.infos64.dyldVersion;
+                               dyld_all_image_infos_address = all_image_infos.infos64.dyldAllImageInfosAddress;
+                       } else {
+                               notification_address = all_image_infos.infos32.notification;
+                               dyld_image_address = all_image_infos.infos32.dyldImageLoadAddress;
+                               dyld_version_address = all_image_infos.infos32.dyldVersion;
+                               dyld_all_image_infos_address = all_image_infos.infos32.dyldAllImageInfosAddress;
+                       }
+
+                       /*
+                        * dyld statically sets up the all_image_infos in its Mach-O
+                        * binary at static link time, with pointers relative to its default
+                        * load address. Since ASLR might slide dyld before its first
+                        * instruction is executed, "dyld_slide_amount" tells us how far
+                        * dyld was loaded compared to its default expected load address.
+                        * All other pointers into dyld's image should be adjusted by this
+                        * amount. At some point later, dyld will fix up pointers to take
+                        * into account the slide, at which point the all_image_infos_address
+                        * field in the structure will match the runtime load address, and
+                        * "dyld_slide_amount" will be 0, if we were to consult it again.
+                        */
+
+                       dyld_slide_amount = load_result->all_image_info_addr - dyld_all_image_infos_address;
+
+#if 0
+                       kprintf("exec_prefault: 0x%016llx 0x%08x 0x%016llx 0x%016llx 0x%016llx 0x%016llx\n",
+                                       (uint64_t)load_result->all_image_info_addr,
+                                       all_image_infos.infos32.version,
+                                       (uint64_t)notification_address,
+                                       (uint64_t)dyld_image_address,
+                                       (uint64_t)dyld_version_address,
+                                       (uint64_t)dyld_all_image_infos_address);
+#endif
+
+                       vm_fault(current_map(),
+                                vm_map_trunc_page(notification_address + dyld_slide_amount,
+                                                  vm_map_page_mask(current_map())),
+                                VM_PROT_READ | VM_PROT_EXECUTE,
+                                FALSE,
+                                THREAD_UNINT, NULL, 0);
+                       vm_fault(current_map(),
+                                vm_map_trunc_page(dyld_image_address + dyld_slide_amount,
+                                                  vm_map_page_mask(current_map())),
+                                VM_PROT_READ | VM_PROT_EXECUTE,
+                                FALSE,
+                                THREAD_UNINT, NULL, 0);
+                       vm_fault(current_map(),
+                                vm_map_trunc_page(dyld_version_address + dyld_slide_amount,
+                                                  vm_map_page_mask(current_map())),
+                                VM_PROT_READ,
+                                FALSE,
+                                THREAD_UNINT, NULL, 0);
+                       vm_fault(current_map(),
+                                vm_map_trunc_page(dyld_all_image_infos_address + dyld_slide_amount,
+                                                  vm_map_page_mask(current_map())),
+                                VM_PROT_READ | VM_PROT_WRITE,
+                                FALSE,
+                                THREAD_UNINT, NULL, 0);
+               }
+       }
+}