]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_exec.c
xnu-1228.tar.gz
[apple/xnu.git] / bsd / kern / kern_exec.c
index 15cac8d966199802ecca8bffc39454b6cb5e326d..ded4a1dcf2c1aa4e532f2102101be9602a681bf7 100644 (file)
@@ -1,31 +1,29 @@
 /*
- * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
+ * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ * 
+ * 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.
  * 
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ 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.
- *
- * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
- * Please see the License for the specific language governing rights and 
+ * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
  * limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_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 <sys/param.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/codesign.h>
 
 #include <bsm/audit_kernel.h>
 
+#include <ipc/ipc_types.h>
+
 #include <mach/mach_types.h>
 #include <mach/task.h>
 #include <mach/thread_act.h>
 #include <mach/mach_vm.h>
 #include <mach/vm_param.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_pager.h>
+#include <vm/vm_protos.h>
 #include <vm/vm_kern.h>
-#include <vm/task_working_set.h>
-#include <vm/vm_shared_memory_server.h>
+
+#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, int, struct __user_sigaction *);
 
 /*
  * 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);
 
@@ -134,11 +170,10 @@ extern struct savearea *get_user_regs(thread_t);
 #include <mach-o/fat.h>
 #include <mach-o/loader.h>
 #include <machine/vmparam.h>
-#if KTRACE   
-#include <sys/ktrace.h>
-#endif
 #include <sys/imgact.h>
 
+#include <sys/sdt.h>
+
 
 /*
  * SIZE_MAXPTR         The maximum size of a user space pointer, in bytes
@@ -150,7 +185,12 @@ extern struct savearea *get_user_regs(thread_t);
 #define        SIZE_MAXPTR             8                               /* 64 bits */
 #define        SIZE_IMG_STRSPACE       (NCARGS - 2 * SIZE_MAXPTR)
 
-int    app_profile = 0;
+/*
+ * 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
 
 extern vm_map_t bsd_pageable_map;
 extern struct fileops vnops;
@@ -160,6 +200,7 @@ extern struct fileops vnops;
                  & ~(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);
 static int execargs_alloc(struct image_params *imgp);
@@ -170,21 +211,13 @@ static int exec_handle_sugid(struct image_params *imgp);
 static int sugid_scripts = 0;
 SYSCTL_INT (_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW, &sugid_scripts, 0, "");
 static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack,
-                                       int customstack, struct proc *p);
+                                       int customstack, 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 *);
 
-/* XXX forward; should be in headers, but can't be for one reason or another */
-extern int grade_binary(cpu_type_t exectype, cpu_subtype_t execsubtype);
-extern void vfork_return(thread_t th_act,
-                               struct proc * p,
-                               struct proc *p2,
-                               register_t *retval);
-
-
-extern char classichandler[32];
-extern uint32_t classichandler_fsid;
-extern long classichandler_fileid;
-
+/* We don't want this one exported */
+__private_extern__
+int  open1(vfs_context_t, struct nameidata *, int, struct vnode_attr *, register_t *);
 
 /*
  * exec_add_string
@@ -193,7 +226,6 @@ extern long classichandler_fileid;
  *
  * Parameters; struct image_params *           image parameter block
  *             user_addr_t                     string to add to strings area
- *             uio_seg                         segment where string is located
  *
  * Returns:    0                       Success
  *             !0                      Failure errno from copyinstr()
@@ -203,7 +235,7 @@ extern long classichandler_fileid;
  *             (imgp->ip_strspace)     updated byte count of space remaining
  */
 static int
-exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg)
+exec_add_string(struct image_params *imgp, user_addr_t str)
 {
         int error = 0;
 
@@ -213,7 +245,7 @@ exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg)
                        error = E2BIG;
                        break;
                }
-               if (IS_UIO_SYS_SPACE(seg)) {
+               if (IS_UIO_SYS_SPACE(imgp->ip_seg)) {
                        char *kstr = CAST_DOWN(char *,str);     /* SAFE */
                        error = copystr(kstr, imgp->ip_strendp, imgp->ip_strspace, &len);
                } else  {
@@ -241,10 +273,13 @@ exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg)
  *
  * Parameters; struct image_params *           image parameter block
  *             char *                          path used to invoke program
- *             uio_seg                         segment where path is located
+ *             int                             segment from which path comes
  *
  * Returns:    int                     0       Success
- *                                     !0      Failure: error number
+ *             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
@@ -259,7 +294,7 @@ exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg)
  *             unacceptable for dyld.
  */
 static int
-exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg)
+exec_save_path(struct image_params *imgp, user_addr_t path, int seg)
 {
        int error;
        size_t  len;
@@ -270,7 +305,7 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg)
 
        len = MIN(MAXPATHLEN, imgp->ip_strspace);
 
-       switch( seg) {
+       switch(seg) {
        case UIO_USERSPACE32:
        case UIO_USERSPACE64:   /* Same for copyin()... */
                error = copyinstr(path, imgp->ip_strings, len, &len);
@@ -292,6 +327,89 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg)
        return(error);
 }
 
+#ifdef IMGPF_POWERPC
+/*
+ * exec_powerpc32_imgact
+ *
+ * Implicitly invoke the PowerPC handler for a byte-swapped image magic
+ * number.  This may happen either as a result of an attempt to invoke a
+ * PowerPC image directly, or indirectly as the interpreter used in an
+ * interpreter script.
+ *
+ * Parameters; struct image_params *   image parameter block
+ *
+ * Returns:    -1              not an PowerPC image (keep looking)
+ *             -3              Success: exec_archhandler_ppc: relookup
+ *             >0              Failure: exec_archhandler_ppc: error number
+ *
+ * Note:       This image activator does not handle the case of a direct
+ *             invocation of the exec_archhandler_ppc, since in that case, the
+ *             exec_archhandler_ppc itself is not a PowerPC binary; instead,
+ *             binary image activators must recognize the exec_archhandler_ppc;
+ *             This is managed in exec_check_permissions().
+ *
+ * Note:       This image activator is limited to 32 bit powerpc images;
+ *             if support for 64 bit powerpc images is desired, it would
+ *             be more in line with this design to write a separate 64 bit
+ *             image activator.
+ */
+static int
+exec_powerpc32_imgact(struct image_params *imgp)
+{
+       struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata;
+       int error;
+       size_t len = 0;
+
+       /*
+        * Make sure it's a PowerPC binary.  If we've already redirected
+        * from an interpreted file once, don't do it again.
+        */
+       if (mach_header->magic != MH_CIGAM) {
+               /*
+                * If it's a cross-architecture 64 bit binary, then claim
+                * it, but refuse to run it.
+                */
+               if (mach_header->magic == MH_CIGAM_64)
+                       return (EBADARCH);
+               return (-1);
+       }
+
+       /* If there is no exec_archhandler_ppc, we can't run it */
+       if (exec_archhandler_ppc.path[0] == 0)
+               return (EBADARCH);
+
+       /* Remember the type of the original file for later grading */
+       if (!imgp->ip_origcputype) {
+               imgp->ip_origcputype = 
+                       OSSwapBigToHostInt32(mach_header->cputype);
+               imgp->ip_origcpusubtype = 
+                       OSSwapBigToHostInt32(mach_header->cpusubtype);
+       }
+
+       /*
+        * The PowerPC flag will be set by the exec_check_permissions()
+        * call anyway; however, we set this flag here so that the relookup
+        * in execve() does not follow symbolic links, as a side effect.
+        */
+       imgp->ip_flags |= IMGPF_POWERPC;
+
+       /* impute an interpreter */
+       error = copystr(exec_archhandler_ppc.path, imgp->ip_interp_name,
+                       IMG_SHSIZE, &len);
+       if (error)
+               return (error);
+
+       /*
+        * provide a replacement string for p->p_comm; we have to use an
+        * an alternate buffer for this, rather than replacing it directly,
+        * since the exec may fail and return to the parent.  In that case,
+        * we would have erroneously changed the parent p->p_comm instead.
+        */
+       strlcpy(imgp->ip_p_comm, imgp->ip_ndp->ni_cnd.cn_nameptr, MAXCOMLEN);
+
+       return (-3);
+}
+#endif /* IMGPF_POWERPC */
 
 
 /*
@@ -299,7 +417,7 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg)
  *
  * 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 Classic mode, and that the length of the script
+ * 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
@@ -322,13 +440,19 @@ exec_shell_imgact(struct image_params *imgp)
        char *ihp;
        char *line_endp;
        char *interp;
+       char temp[16];
+       proc_t p;
+       struct fileproc *fp;
+       int fd;
+       int error;
+       size_t len;
 
        /*
         * Make sure it's a shell script.  If we've already redirected
         * from an interpreted file once, don't do it again.
         *
-        * Note: We disallow Classic, since the expectation is that we
-        * may run a Classic interpreter, but not an interpret a Classic
+        * 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.
         */
        if (vdata[0] != '#' ||
@@ -337,6 +461,10 @@ exec_shell_imgact(struct image_params *imgp)
                return (-1);
        }
 
+#ifdef IMGPF_POWERPC
+       if ((imgp->ip_flags & IMGPF_POWERPC) != 0)
+                 return (EBADARCH);
+#endif /* IMGPF_POWERPC */
 
        imgp->ip_flags |= IMGPF_INTERPRET;
 
@@ -399,6 +527,34 @@ exec_shell_imgact(struct image_params *imgp)
                imgp->ip_argc++;
        }
 
+       /*
+        * 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 (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);
+
+               fp->f_fglob->fg_flag = FREAD;
+               fp->f_fglob->fg_type = DTYPE_VNODE;
+               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);
+
+               snprintf(temp, sizeof(temp), "/dev/fd/%d", fd);
+               error = copyoutstr(temp, imgp->ip_user_fname, sizeof(temp), &len);
+               if (error)
+                       return(error);
+       }
+
        return (-3);
 }
 
@@ -413,9 +569,19 @@ exec_shell_imgact(struct image_params *imgp)
  * 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:       If we find an encapsulated binary, we make no assertions
+ * 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.
@@ -423,9 +589,10 @@ exec_shell_imgact(struct image_params *imgp)
 static int
 exec_fat_imgact(struct image_params *imgp)
 {
-       struct proc *p = vfs_context_proc(imgp->ip_vfs_context);
-       kauth_cred_t cred = p->p_ucred;
+       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;
@@ -437,6 +604,49 @@ exec_fat_imgact(struct image_params *imgp)
                goto bad;
        }
 
+       /* 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;
+
+               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;
+                       }
+
+                       if (pref == CPU_TYPE_ANY) {
+                               /* Fall through to regular grading */
+                               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;
+                               }
+                       }
+               }
+       }
+
        /* Look up our preferred architecture in the fat file. */
        lret = fatfile_getarch_affinity(imgp->ip_vp,
                                        (vm_offset_t)fat_header,
@@ -447,7 +657,8 @@ exec_fat_imgact(struct image_params *imgp)
                goto bad;
        }
 
-       /* Read the Mach-O header out of it */
+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_SYSSPACE32, (IO_UNIT|IO_NODELOCKED),
@@ -468,6 +679,7 @@ exec_fat_imgact(struct image_params *imgp)
        imgp->ip_arch_size = (user_size_t)fat_arch.size;
 
 bad:
+       kauth_cred_unref(&cred);
        return (error);
 }
 
@@ -476,27 +688,41 @@ bad:
  *
  * 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;
-       kauth_cred_t            cred = vfs_context_ucred(imgp->ip_vfs_context);
-       struct proc             *p = vfs_context_proc(imgp->ip_vfs_context);
+       proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
        int                     error = 0;
        int                     vfexec = 0;
        task_t                  task;
-       task_t                  new_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;
-       boolean_t                               clean_regions = FALSE;
-    shared_region_mapping_t initial_region = NULL;
        load_return_t           lret;
        load_result_t           load_result;
-               
+       struct _posix_spawnattr *psa = NULL;
+
        /*
         * 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
@@ -504,10 +730,22 @@ exec_mach_imgact(struct image_params *imgp)
         */
        if ((mach_header->magic != MH_MAGIC) &&
            (mach_header->magic != MH_MAGIC_64)) {
-       error = -1;
+               error = -1;
+               goto bad;
+       }
+
+       switch (mach_header->filetype) {
+       case MH_DYLIB:
+       case MH_BUNDLE:
+               error = -1;
                goto bad;
        }
 
+       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);
@@ -518,22 +756,43 @@ exec_mach_imgact(struct image_params *imgp)
        if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64)
                imgp->ip_flags |= IMGPF_IS_64BIT;
 
-       if (!grade_binary(mach_header->cputype, mach_header->cpusubtype)) {
+       /* 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;
        }
-
-       /*
-        * Copy in arguments/environment from the old process, if the
-        * vector is non-NULL (i.e. exec is not being called from
-        * load_init_program(), as a special case, at system startup).
-        */
-       if (imgp->ip_user_argv != 0LL) {
-               error = exec_extract_strings(imgp);
-               if (error)
-                       goto bad;
+grade:
+       if (!grade_binary(imgp->ip_origcputype & ~CPU_SUBTYPE_LIB64, 
+                               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;
+
        /*
         * Hack for binary compatability; put three NULs on the end of the
         * string area, and round it up to the next word boundary.  This
@@ -544,25 +803,32 @@ exec_mach_imgact(struct image_params *imgp)
        imgp->ip_strendp[2] = 0;
        imgp->ip_strendp += (((imgp->ip_strendp - imgp->ip_strings) + NBPW-1) & ~(NBPW-1));
 
+#ifdef IMGPF_POWERPC
+       /*
+        * XXX
+        *
+        * Should be factored out; this is here because we might be getting
+        * invoked this way as the result of a shell script, and the check
+        * in exec_check_permissions() is not interior to the jump back up
+        * to the "encapsulated_binary:" label in exec_activate_image().
+        */
+       if (imgp->ip_vattr->va_fsid == exec_archhandler_ppc.fsid &&
+               imgp->ip_vattr->va_fileid == (uint64_t)((u_long)exec_archhandler_ppc.fileid)) {
+               imgp->ip_flags |= IMGPF_POWERPC;
+       }
+#endif /* IMGPF_POWERPC */
 
        if (vfexec) {
-               kern_return_t   result;
-
-               result = task_create_internal(task, FALSE, &new_task);
-               if (result != KERN_SUCCESS)
-               printf("execve: task_create failed. Code: 0x%x\n", result);
-               p->task = new_task;
-               set_bsdtask_info(new_task, p);
-               if (p->p_nice != 0)
-                       resetpriority(p);
-               map = get_task_map(new_task);
-               result = thread_create(new_task, &imgp->ip_vfork_thread);
-               if (result != KERN_SUCCESS)
-               printf("execve: thread_create failed. Code: 0x%x\n", result);
-               /* reset local idea of task, thread, uthread */
-               task = new_task;
+               imgp->ip_vfork_thread = fork_create_child(task, p, FALSE, (imgp->ip_flags & IMGPF_IS_64BIT));
+               if (imgp->ip_vfork_thread == NULL) {
+                       error = ENOMEM;
+                       goto bad;
+               }
+               /* reset local idea of thread, uthread, task */
                thread = imgp->ip_vfork_thread;
                uthread = get_bsdthread_info(thread);
+               task = new_task = get_threadtask(thread);
+               map = get_task_map(task);
        } else {
                map = VM_MAP_NULL;
        }
@@ -573,25 +839,16 @@ exec_mach_imgact(struct image_params *imgp)
         */
        if (imgp->ip_flags & IMGPF_IS_64BIT) {
                task_set_64bit(task, TRUE);
-               p->p_flag |= P_LP64;
+               OSBitOrAtomic(P_LP64, (UInt32 *)&p->p_flag);
        } else {
                task_set_64bit(task, FALSE);
-               p->p_flag &= ~P_LP64;
+               OSBitAndAtomic(~((uint32_t)P_LP64), (UInt32 *)&p->p_flag);
        }
 
        /*
         *      Load the Mach-O file.
         */
-/* LP64 - remove following "if" statement after osfmk/vm/task_working_set.c */
-if((imgp->ip_flags & IMGPF_IS_64BIT) == 0)
-       if(imgp->ip_tws_cache_name) {
-               tws_handle_startup_file(task, kauth_cred_getuid(cred), 
-                       imgp->ip_tws_cache_name, imgp->ip_vp, &clean_regions);
-       }
-
-       vm_get_shared_region(task, &initial_region);
 
-       
        /*
         * NOTE: An error after this point  indicates we have potentially
         * destroyed or overwrote some process state while attempting an
@@ -602,47 +859,85 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0)
         * We reset the task to 64-bit (or not) here.  It may have picked up
         * a new map, and we need that to reflect its true 64-bit nature.
         */
+
        task_set_64bit(task, 
                       ((imgp->ip_flags & IMGPF_IS_64BIT) == IMGPF_IS_64BIT));
 
        /*
         * Actually load the image file we previously decided to load.
         */
-       lret = load_machfile(imgp, mach_header, thread, map, clean_regions, &load_result);
+       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_EXEC_SET_HARD|CS_EXEC_SET_KILL);
+       } 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;
+
+
        /* load_machfile() maps the vnode */
-       (void)ubc_map(imgp->ip_vp, PROT_EXEC);
+       (void)ubc_map(imgp->ip_vp, PROT_READ | PROT_EXEC);
+
+       /*
+        * 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,
+#ifdef IMGPF_POWERPC
+                   imgp->ip_flags & IMGPF_POWERPC ?
+                   CPU_TYPE_POWERPC :
+#endif
+                   cpu_type());
+       
+       /*
+        * Close file descriptors
+        * which specify close-on-exec.
+        */
+       fdexec(p);
 
        /*
         * deal with set[ug]id.
         */
        error = exec_handle_sugid(imgp);
 
-       KNOTE(&p->p_klist, NOTE_EXEC);
+       proc_knote(p, NOTE_EXEC);
 
-       if (!vfexec && (p->p_flag & P_TRACED))
+       if (!vfexec && (p->p_lflag & P_LTRACED))
                psignal(p, SIGTRAP);
 
        if (error) {
                goto badtoolate;
        }
-       vnode_put(imgp->ip_vp);
-       imgp->ip_vp = NULL;
        
        if (load_result.unixproc &&
                create_unix_stack(get_task_map(task),
-                                 load_result.user_stack, load_result.customstack, p)) {
+                                 load_result.user_stack,
+                                 load_result.customstack,
+                                 p) != KERN_SUCCESS) {
                error = load_return_to_errno(LOAD_NOSPACE);
                goto badtoolate;
        }
 
        if (vfexec) {
-               uthread->uu_ar0 = (void *)get_user_regs(thread);
                old_map = vm_map_switch(get_task_map(task));
        }
 
@@ -670,10 +965,15 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0)
                /* Adjust the stack */
                if (imgp->ip_flags & IMGPF_IS_64BIT) {
                        ap = thread_adjuserstack(thread, -8);
-                       (void)copyoutptr(load_result.mach_header, ap, 8);
+                       error = copyoutptr(load_result.mach_header, ap, 8);
                } else {
                        ap = thread_adjuserstack(thread, -4);
-                       (void)suword(ap, load_result.mach_header);
+                       error = suword(ap, load_result.mach_header);
+               }
+               if (error) {
+                       if (vfexec)
+                               vm_map_switch(old_map);
+                       goto badtoolate;
                }
        }
 
@@ -691,23 +991,21 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0)
         */
        execsigs(p, thread);
 
-       /*
-        * Close file descriptors
-        * which specify close-on-exec.
-        */
-       fdexec(p);
-
        /*
         * need to cancel async IO requests that can be cancelled and wait for those
         * already active.  MAY BLOCK!
         */
        _aio_exec( p );
 
+#if SYSV_SHM
        /* FIXME: Till vmspace inherit is fixed: */
        if (!vfexec && p->vm_shm)
                shmexec(p);
+#endif
+#if SYSV_SEM
        /* Clean up the semaphores */
        semexit(p);
+#endif
 
        /*
         * Remember file name for accounting.
@@ -728,44 +1026,103 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0)
                p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0';
        }
 
-       {
-         /* This is for kdebug */
-         long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4;
+#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);
+
 
-         /* Collect the pathname for tracing */
-         kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4);
+       /*
+        * 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)
-         {
-                 KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE,
-                                       p->p_pid ,0,0,0, (unsigned int)thread);
-                 KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
+               if (vfexec) {
+                       KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE,
+                                       p->p_pid ,0,0,0, (unsigned int)thread);
+                       KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
                                        dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (unsigned int)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,
+               } 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);
-         }
+               }
        }
 
-               p->p_flag &= ~P_CLASSIC;
+#ifdef IMGPF_POWERPC
+       /*
+        * Mark the process as powerpc or not.  If powerpc, set the affinity
+        * flag, which will be used for grading binaries in future exec's
+        * from the process.
+        */
+       if (((imgp->ip_flags & IMGPF_POWERPC) != 0))
+               OSBitOrAtomic(P_TRANSLATED, (UInt32 *)&p->p_flag);
+       else
+#endif /* IMGPF_POWERPC */
+               OSBitAndAtomic(~((uint32_t)P_TRANSLATED), (UInt32 *)&p->p_flag);
+       OSBitAndAtomic(~((uint32_t)P_AFFINITY), (UInt32 *)&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);
+               }
+       }
 
        /*
         * mark as execed, wakeup the process that vforked (if any) and tell
         * it that it now has it's 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, (UInt32 *)&p->p_flag);
+       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);
        }
 
-       if (vfexec && (p->p_flag & P_TRACED)) {
+       if (vfexec && (p->p_lflag & P_LTRACED)) {
                psignal_vfork(p, new_task, thread, SIGTRAP);
        }
 
@@ -797,77 +1154,52 @@ struct execsw {
 } execsw[] = {
        { exec_mach_imgact,             "Mach-o Binary" },
        { exec_fat_imgact,              "Fat Binary" },
+#ifdef IMGPF_POWERPC
+       { exec_powerpc32_imgact,        "PowerPC binary" },
+#endif /* IMGPF_POWERPC */
        { exec_shell_imgact,            "Interpreter Script" },
        { NULL, NULL}
 };
 
 
 /*
- * TODO:       Dynamic linker header address on stack is copied via suword()
+ * 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]
  */
-/* ARGSUSED */
-int
-execve(struct proc *p, struct execve_args *uap, register_t *retval)
+static int
+exec_activate_image(struct image_params *imgp)
 {
-       kauth_cred_t cred = p->p_ucred;
-       struct image_params image_params, *imgp;
-       struct vnode_attr va;
-       struct vnode_attr origva;
        struct nameidata nd;
-       struct uthread          *uthread;
-       int i;
-       int resid, error;
-       task_t  task;
-       int numthreads;
-       int vfexec=0;
+       int error;
+       int resid;
        int once = 1;   /* save SGUID-ness for interpreted files */
-       char alt_p_comm[sizeof(p->p_comm)] = {0};       /* for Classic */
-       int is_64 = IS_64BIT_PROCESS(p);
-       int seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32);
-       struct vfs_context context;
-
-       context.vc_proc = p;
-       context.vc_ucred = p->p_ucred;  /* XXX must NOT be kauth_cred_get() */
-
-
-       imgp = &image_params;
-
-       /* Initialize the common data in the image_params structure */
-       bzero(imgp, sizeof(*imgp));
-       imgp->ip_user_fname = uap->fname;
-       imgp->ip_user_argv = uap->argp;
-       imgp->ip_user_envv = uap->envp;
-       imgp->ip_vattr = &va;
-       imgp->ip_origvattr = &origva;
-       imgp->ip_vfs_context = &context;
-       imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT : IMGPF_NONE);
-       imgp->ip_tws_cache_name = NULL;
-       imgp->ip_p_comm = alt_p_comm;           /* for Classic */
-
-       /*
-         * XXXAUDIT: Currently, we only audit the pathname of the binary.
-         * There may also be poor interaction with dyld.
-         */
-
-       task = current_task();
-       uthread = get_bsdthread_info(current_thread());
-
-       if (uthread->uu_flag & UT_VFORK) {
-                       vfexec = 1; /* Mark in exec */
-       } else {
-               if (task != kernel_task) { 
-                       numthreads = get_task_numacts(task);
-                       if (numthreads <= 0 )
-                               return(EINVAL);
-                       if (numthreads > 1) {
-                               return(ENOTSUP);
-                       }
-               }
-       }
+       int i;
+       int iterlimit = EAI_ITERLIMIT;
 
        error = execargs_alloc(imgp);
        if (error)
-               return(error);
+               goto bad;
        
        /*
         * XXXAUDIT: Note: the double copyin introduces an audit
@@ -875,33 +1207,15 @@ execve(struct proc *p, struct execve_args *uap, register_t *retval)
         * copyin(), e.g. by passing a flag to namei to indicate an
         * external path buffer is being used.
         */
-       error = exec_save_path(imgp, uap->fname, seg);
+       error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg);
        if (error) {
-               execargs_free(imgp);
-               return(error);
+               goto bad;
        }
 
-       /*
-        * No app profiles under chroot
-        */
-       if((p->p_fd->fd_rdir == NULLVP) && (app_profile != 0)) {
-
-               /* grab the name of the file out of its path */
-               /* we will need this for lookup within the   */
-               /* name file */
-               /* Scan backwards for the first '/' or start of string */
-               imgp->ip_tws_cache_name = imgp->ip_strendp;
-                       while (imgp->ip_tws_cache_name[0] != '/') {
-                               if(imgp->ip_tws_cache_name == imgp->ip_strings) {
-                                       imgp->ip_tws_cache_name--;
-                                       break;
-                       }
-                               imgp->ip_tws_cache_name--;
-                       }
-                       imgp->ip_tws_cache_name++;
-       }
+       DTRACE_PROC1(exec, uintptr_t, imgp->ip_strings);
+
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
-               seg, uap->fname, imgp->ip_vfs_context);
+               imgp->ip_seg, imgp->ip_user_fname, imgp->ip_vfs_context);
 
 again:
        error = namei(&nd);
@@ -917,15 +1231,22 @@ again:
        /* Copy; avoid invocation of an interpreter overwriting the original */
        if (once) {
                once = 0;
-               origva = va;
+               *imgp->ip_origvattr = *imgp->ip_vattr;
        }
 
        error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0,
-                       UIO_SYSSPACE32, IO_NODELOCKED, cred, &resid, p);
+                       UIO_SYSSPACE32, 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++) {
 
@@ -937,12 +1258,37 @@ encapsulated_binary:
                        goto encapsulated_binary;
 
                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);
+#endif
                        vnode_put(imgp->ip_vp);
                        imgp->ip_vp = NULL;     /* already put */
                        nd.ni_cnd.cn_nameiop = LOOKUP;
                        nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) |
                                                (FOLLOW | LOCKLEAF);
 
+#ifdef IMGPF_POWERPC
+                       /*
+                        * PowerPC does not follow symlinks because the
+                        * code which sets exec_archhandler_ppc.fsid and
+                        * exec_archhandler_ppc.fileid doesn't follow them.
+                        */
+                       if (imgp->ip_flags & IMGPF_POWERPC)
+                               nd.ni_cnd.cn_flags &= ~FOLLOW;
+#endif /* IMGPF_POWERPC */
 
                        nd.ni_segflg = UIO_SYSSPACE32;
                        nd.ni_dirp = CAST_USER_ADDR_T(imgp->ip_interp_name);
@@ -952,35 +1298,743 @@ encapsulated_binary:
                        break;
                }
        }
-       
-       /* call out to allow 3rd party notification of exec. 
+
+       /*
+        * 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(&context), KAUTH_FILEOP_EXEC, 
-                                                          (uintptr_t)nd.ni_vp, 0);
+               kauth_authorize_fileop(vfs_context_ucred(imgp->ip_vfs_context),
+                                       KAUTH_FILEOP_EXEC,
+                                       (uintptr_t)nd.ni_vp, 0);
        }
-       
-       /* Image not claimed by any activator? */
-       if (error == -1)
-               error = ENOEXEC;
 
 bad:
-       if (imgp->ip_ndp)
-               nameidone(imgp->ip_ndp);
-       if (imgp->ip_vp)
-               vnode_put(imgp->ip_vp);
        if (imgp->ip_strings)
                execargs_free(imgp);
-       if (!error && vfexec) {
-                       vfork_return(current_thread(), p->p_pptr, p, retval);
-                       (void)thread_resume(imgp->ip_vfork_thread);
-                       return(0);
-       }
-       return(error);
-}
-
+       if (imgp->ip_ndp)
+               nameidone(imgp->ip_ndp);
+
+       return (error);
+}
+
+/*
+ * exec_handle_port_actions
+ *
+ * Description:        Go through the _posix_port_actions_t contents, 
+ *             calling task_set_special_port and task_set_exception_ports
+ *             for the current task.
+ *
+ * Parameters: struct image_params *   Image parameter block
+ *
+ * Returns:    0                       Success
+ *             KERN_FAILURE            Failure
+ */
+static int
+exec_handle_port_actions(struct image_params *imgp)
+{
+       _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;
+       kern_return_t ret = KERN_SUCCESS;
+       int i;
+
+       for (i = 0; i < pacts->pspa_count; i++) {
+               act = &pacts->pspa_actions[i];
+
+               ret = ipc_object_copyin(get_task_ipcspace(current_task()),
+                               (mach_port_name_t) act->new_port,
+                               MACH_MSG_TYPE_COPY_SEND,
+                               (ipc_object_t *) &port);
+
+               if (ret)                        
+                       return ret;
+
+               switch (act->port_type) {
+                       case PSPA_SPECIAL:
+                               ret = task_set_special_port(task, 
+                                               act->which, 
+                                               port);
+                               break;
+                       case PSPA_EXCEPTION:
+                               ret = task_set_exception_ports(task, 
+                                               act->mask,
+                                               port, 
+                                               act->behavior, 
+                                               act->flavor);
+                               break;
+                       default:
+                               ret = KERN_FAILURE;
+               }
+               /* action failed, so release port resources */
+               if (ret) { 
+                       ipc_port_release_send(port);
+                       return ret;
+               }
+       }
+
+       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)
+{
+       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;
+       register_t 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 oof 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, 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,
+                                       ival);
+
+                       /*
+                        * If there's an error, or we get the right fd by
+                        * accident, then drop out here.  This is easier that
+                        * rearchitecting 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;
+
+               default:
+                       error = EINVAL;
+                       break;
+               }
+               /* All file actions failures are considered fatal, per POSIX */
+               if (error)
+                       break;
+       }
+
+       return (error);
+}
+
+
+/*
+ * 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:       More gracefully handle failures after vfork
+ *             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, register_t *retval)
+{
+       proc_t p = ap;          /* quiet bogus GCC vfork() warning */
+       register_t ival[2];             /* dummy retval for vfork() */
+       struct image_params image_params, *imgp;
+       struct vnode_attr va;
+       struct vnode_attr origva;
+       struct uthread  *uthread = 0;   /* compiler complains if not set to 0*/
+       int error, sig;
+       task_t  task;
+       int numthreads;
+       char alt_p_comm[sizeof(p->p_comm)] = {0};       /* for PowerPC */
+       int is_64 = IS_64BIT_PROCESS(p);
+       int undo_vfork = 0;
+       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 __user_sigaction vec;
+
+       imgp = &image_params;
+
+       /* Initialize the common data in the image_params structure */
+       bzero(imgp, sizeof(*imgp));
+       imgp->ip_user_fname = uap->path;
+       imgp->ip_user_argv = uap->argv;
+       imgp->ip_user_envv = uap->envp;
+       imgp->ip_vattr = &va;
+       imgp->ip_origvattr = &origva;
+       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 _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);
+               }
+               if (error)
+                       goto bad;
+
+               if (px_args.attr_size != 0) {
+                       /* 
+                        * This could lose some of the port_actions pointer, 
+                        * but we already have it from px_args. 
+                        */
+                       if ((error = copyin(px_args.attrp, &px_sa, sizeof(px_sa))) != 0)
+                       goto bad;
+
+                       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;
+               }
+               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;
+               }
+       }
+
+       if (imgp->ip_px_sa == NULL || !(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)){
+               if ((error = vfork(p, NULL, ival)) != 0)
+                       goto bad;
+               undo_vfork = 1;
+       }
+
+       /* "reenter the kernel" on a new vfork()'ed process */
+       uthread = get_bsdthread_info(current_thread());
+       if (undo_vfork)
+               p = uthread->uu_proc;
+
+       context.vc_thread = current_thread();
+       context.vc_ucred = p->p_ucred;  /* XXX must NOT be kauth_cred_get() */
+
+       /*
+        * 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 &&
+           (error = exec_handle_file_actions(imgp)) != 0) {
+               goto bad;
+       }
+
+       /* Has spawn port actions? */
+       if (imgp->ip_px_spa != NULL) { 
+               /* Only allowed when not under vfork */
+               if (!(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)) {
+                       error = ENOTSUP;
+                       goto bad;
+               }
+               if((error = exec_handle_port_actions(imgp)) != 0) 
+                       goto bad;
+       }
+
+       /* Has spawn attr? */
+       if (imgp->ip_px_sa != NULL) {
+               /* Set the process group ID of the child process */
+               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().
+                *
+                * 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, my_cred->cr_ruid, my_cred->cr_rgid);
+                       if (my_new_cred != my_cred)
+                               p->p_ucred = my_new_cred;
+               }
+               /*
+                * 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)
+                       uthread->uu_sigmask = (px_sa.psa_sigmask & ~sigcantmask);
+               /*
+                * Default a list of signals instead of ignoring them, if
+                * they were ignored in the parent.
+                */
+               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, sig, &vec);
+                       }
+               }
+       }
+
+       /*
+         * XXXAUDIT: Currently, we only audit the pathname of the binary.
+         * There may also be poor interaction with dyld.
+         */
+
+       task = current_task();
+
+       /* If we're not in vfork, don't permit a mutithreaded task to exec */
+       if (!(uthread->uu_flag & UT_VFORK)) {
+               if (task != kernel_task) { 
+                       numthreads = get_task_numacts(task);
+                       if (numthreads <= 0 ) {
+                               error = EINVAL;
+                               goto bad;
+                       }
+                       if (numthreads > 1) {
+                               error = ENOTSUP;
+                               goto bad;
+                       }
+               }
+       }
+
+#if MAC_SPAWN  /* XXX */
+       if (uap->mac_p != USER_ADDR_NULL) {
+               error = mac_execve_enter(uap->mac_p, imgp);
+               if (error)
+                       goto bad;
+       }
+#endif
+
+       if ((error = exec_activate_image(imgp)) != 0) 
+               goto bad;
+bad:
+       /* Image not claimed by any activator? */
+       if (error == -1)
+               error = ENOEXEC;
+       if (error == 0) {
+               exec_resettextvp(p, imgp);
+       }       
+       if (imgp->ip_vp)
+               vnode_put(imgp->ip_vp);
+       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_execlabelp)
+               mac_cred_label_free(imgp->ip_execlabelp);
+       if (imgp->ip_scriptlabelp)
+               mac_vnode_label_free(imgp->ip_scriptlabelp);
+#endif
+       if (undo_vfork) {
+               if (error) {
+                       DTRACE_PROC1(exec__failure, int, error);
+                       vfork_exit(p, W_EXITCODE(-1, 0));
+               } else {
+                       DTRACE_PROC(exec__success);
+               }
+               /*
+                * Returning to the parent process...
+                *
+                * If the parent wants the pid, copy it out
+                */
+               if (uap->pid != USER_ADDR_NULL)
+                       (void)suword(uap->pid, p->p_pid);
+               retval[0] = error;
+               /*
+                * 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);
+               vfork_return(p, NULL, error);
+               (void)thread_resume(imgp->ip_vfork_thread);
+       }
+
+       if (!error) {
+               /*
+                * 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);
+               DTRACE_PROC(exec__success);
+       } else {
+               DTRACE_PROC1(exec__failure, int, error);
+       }
+
+       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, register_t *retval)
+{
+       struct __mac_execve_args muap;
+       int err;
+
+       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, register_t *retval)
+{
+       struct image_params image_params, *imgp;
+       struct vnode_attr va;
+       struct vnode_attr origva;
+       struct uthread          *uthread;
+       int error;
+       task_t  task;
+       int numthreads;
+       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() */
+
+       imgp = &image_params;
 
+       /* Initialize the common data in the image_params structure */
+       bzero(imgp, sizeof(*imgp));
+       imgp->ip_user_fname = uap->fname;
+       imgp->ip_user_argv = uap->argp;
+       imgp->ip_user_envv = uap->envp;
+       imgp->ip_vattr = &va;
+       imgp->ip_origvattr = &origva;
+       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);
+
+       /*
+         * XXXAUDIT: Currently, we only audit the pathname of the binary.
+         * There may also be poor interaction with dyld.
+         */
+
+       task = current_task();
+       uthread = get_bsdthread_info(current_thread());
+
+       /* If we're not in vfork, don't permit a mutithreaded task to exec */
+       if (!(uthread->uu_flag & UT_VFORK)) {
+               if (task != kernel_task) { 
+                       proc_lock(p);
+                       numthreads = get_task_numacts(task);
+                       if (numthreads <= 0 ) {
+                               proc_unlock(p);
+                               kauth_cred_unref(&context.vc_ucred);
+                               return(EINVAL);
+                       }
+                       if (numthreads > 1) {
+                               proc_unlock(p);
+                               kauth_cred_unref(&context.vc_ucred);
+                               return(ENOTSUP);
+                       }
+                       proc_unlock(p);
+               }
+       }
+
+#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);
+                       return (error);
+               }
+       }
+#endif
+
+       proc_transstart(p, 0);
+       error = exec_activate_image(imgp);
+       proc_transend(p, 0);
+
+       kauth_cred_unref(&context.vc_ucred);
+       
+       /* Image not claimed by any activator? */
+       if (error == -1)
+               error = ENOEXEC;
+
+       if (error == 0) {
+               exec_resettextvp(p, imgp);
+       }       
+       if (imgp->ip_vp != NULLVP)
+               vnode_put(imgp->ip_vp);
+       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) {
+               /*
+                * 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);
+               DTRACE_PROC(exec__success);
+
+               if (uthread->uu_flag & UT_VFORK) {
+                       vfork_return(p, retval, p->p_pid);
+                       (void)thread_resume(imgp->ip_vfork_thread);
+               }
+       } else {
+               DTRACE_PROC1(exec__failure, int, error);
+       }
+       
+       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)
 {
@@ -999,6 +2053,22 @@ copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size)
 }
 
 
+/*
+ * 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'
+ *
+ * Implicit returns:
+ *             *ptr_size               Modified
+ */
 static int
 copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size)
 {
@@ -1084,7 +2154,7 @@ copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size)
 static int
 exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
 {
-       struct proc *p = vfs_context_proc(imgp->ip_vfs_context);
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
        int     ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4;
        char    *argv = imgp->ip_argv;  /* modifiable copy of argv */
        user_addr_t     string_area;    /* *argv[], *env[] */
@@ -1098,6 +2168,9 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
 
        stack = *stackp;
 
+       unsigned patharea_len = imgp->ip_argv - imgp->ip_strings;
+       int envc_add = 0;
+       
        /*
         * Set up pointers to the beginning of the string area, the beginning
         * of the path area, and the beginning of the pointer area (actually,
@@ -1105,8 +2178,8 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
         * but we use ptr_size worth of space for it, for alignment).
         */
        string_area = stack - (((imgp->ip_strendp - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1)) - ptr_size;
-       path_area = string_area - (((imgp->ip_argv - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1));
-       ptr_area = path_area - ((imgp->ip_argc + imgp->ip_envc + 4) * ptr_size) - ptr_size /*argc*/;
+       path_area = string_area - ((patharea_len + ptr_size-1) & ~(ptr_size-1));
+       ptr_area = path_area - ((imgp->ip_argc + imgp->ip_envc + 4 + envc_add) * ptr_size) - ptr_size /*argc*/;
 
        /* Return the initial stack address: the location of argc */
        *stackp = ptr_area;
@@ -1115,8 +2188,10 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
         * 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)(stack - path_area);
+       proc_unlock(p);
 
 
        /*
@@ -1126,7 +2201,7 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
         */
        len = 0;
        error = copyoutstr(imgp->ip_strings, path_area,
-                               (unsigned)(imgp->ip_argv - imgp->ip_strings),
+                                                  patharea_len,
                                (size_t *)&len);
        if (error)
                goto bad;
@@ -1154,6 +2229,9 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
                ptr_area += sizeof(int);
        }
 
+#if CONFIG_DTRACE
+       p->p_dtrace_argv = ptr_area; /* user_addr_t &argv[0] for dtrace convenience */
+#endif /* CONFIG_DTRACE */
 
        /*
         * We use (string_area - path_area) here rather than the more
@@ -1169,6 +2247,9 @@ exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
                        /* argv[n] = NULL */
                        (void)copyoutptr(0LL, ptr_area, ptr_size);
                        ptr_area += ptr_size;
+#if CONFIG_DTRACE
+                       p->p_dtrace_envp = ptr_area; /* user_addr_t &env[0] for dtrace convenience */
+#endif /* CONFIG_DTRACE */
                }
                if (--stringc < 0)
                        break;
@@ -1218,19 +2299,24 @@ bad:
  *             (imgp->ip_envc)         Count of environment strings, updated
  *
  *
- * Notes:      The argument and environment vectors are user space pointers
+ * 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;
-       struct proc *p = vfs_context_proc(imgp->ip_vfs_context);
-       int seg = (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32);
        int     ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT) ? 8 : 4;
        user_addr_t     argv = imgp->ip_user_argv;
        user_addr_t     envv = imgp->ip_user_envv;
 
+       /*
+        * If the argument vector is NULL, this is the system startup
+        * bootstrap from load_init_program(), and there's nothing to do
+        */
+       if (imgp->ip_user_argv == 0LL)
+               goto bad;
+
        /* Now, get rest of arguments */
 
        /*
@@ -1247,7 +2333,7 @@ exec_extract_strings(struct image_params *imgp)
                        goto bad;
                if (arg != 0LL && arg != (user_addr_t)-1) {
                        argv += ptr_size;
-                       error = exec_add_string(imgp, imgp->ip_user_fname, seg);
+                       error = exec_add_string(imgp, imgp->ip_user_fname);
                        if (error)
                                goto bad;
                        imgp->ip_argc++;
@@ -1272,7 +2358,7 @@ exec_extract_strings(struct image_params *imgp)
                /*
                * av[n...] = arg[n]
                */
-               error = exec_add_string(imgp, arg, seg);
+               error = exec_add_string(imgp, arg);
                if (error)
                        goto bad;
                imgp->ip_argc++;
@@ -1296,7 +2382,7 @@ exec_extract_strings(struct image_params *imgp)
                /*
                * av[n...] = env[n]
                */
-               error = exec_add_string(imgp, env, seg);
+               error = exec_add_string(imgp, env);
                if (error)
                        goto bad;
                imgp->ip_envc++;
@@ -1308,12 +2394,28 @@ bad:
 
 #define        unix_stack_size(p)      (p->p_rlimit[RLIMIT_STACK].rlim_cur)
 
+/*
+ * exec_check_permissions
+ *
+ * Decription: 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;
-       struct proc *p = vfs_context_proc(imgp->ip_vfs_context);
+       proc_t p = vfs_context_proc(imgp->ip_vfs_context);
        int error;
        kauth_action_t action;
 
@@ -1348,34 +2450,64 @@ exec_check_permissions(struct image_params *imgp)
        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_flag & P_TRACED))
+       if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_lflag & P_LTRACED)) {
                vap->va_mode &= ~(VSUID | VSGID);
+#if CONFIG_MACF
+               imgp->ip_no_trans = 1;
+#endif
+       }
+
+#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_flag & P_TRACED)
+       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 */
-       if (vp->v_writecount)
+       vnode_lock(vp);
+       if (vp->v_writecount) {
+               panic("going to return ETXTBSY %x", vp);
+               vnode_unlock(vp);
                return (ETXTBSY);
+       }
+       vnode_unlock(vp);
+#endif
+
 
+#ifdef IMGPF_POWERPC
+       /*
+        * If the file we are about to attempt to load is the exec_handler_ppc,
+        * which is determined by matching the vattr fields against previously
+        * cached values, then we set the PowerPC environment flag.
+        */
+       if (vap->va_fsid == exec_archhandler_ppc.fsid &&
+               vap->va_fileid == (uint64_t)((u_long)exec_archhandler_ppc.fileid)) {
+               imgp->ip_flags |= IMGPF_POWERPC;
+       }
+#endif /* IMGPF_POWERPC */
 
        /* 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 SUGI, then replace the credential with a
+ * 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,
  *
@@ -1399,49 +2531,113 @@ static int
 exec_handle_sugid(struct image_params *imgp)
 {
        kauth_cred_t            cred = vfs_context_ucred(imgp->ip_vfs_context);
-       struct proc             *p = vfs_context_proc(imgp->ip_vfs_context);
+       proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
        int                     i;
+       int                     is_member = 0;
        int                     error = 0;
-       static struct vnode     *dev_null = NULLVP;
+       struct vnode    *dev_null = NULLVP;
+#if CONFIG_MACF
+       kauth_cred_t    my_cred;
+#endif
 
-       p->p_flag &= ~P_SUGID;
+#if CONFIG_MACF
+       int                     mac_transition;
+       mac_transition = mac_cred_check_label_update_execve(imgp->ip_vfs_context, imgp->ip_vp,
+           imgp->ip_scriptlabelp, imgp->ip_execlabelp, p);
+#endif
+
+       OSBitAndAtomic(~((uint32_t)P_SUGID), (UInt32 *)&p->p_flag);
 
+       /*
+        * Order of the following is important; group checks must go last,
+        * as we use the success of the 'is_member' 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) ||
+#if CONFIG_MACF
+               mac_transition ||       /* A policy wants to transition */
+#endif
            ((imgp->ip_origvattr->va_mode & VSGID) != 0 &&
-            cred->cr_gid != imgp->ip_origvattr->va_gid)) {
-#if KTRACE
+                ((kauth_cred_ismember_gid(cred, imgp->ip_origvattr->va_gid, &is_member) || !is_member) ||
+                (cred->cr_gid != imgp->ip_origvattr->va_gid)))) {
+
                /*
-                * If process is being ktraced, turn off - unless
-                * root set it.
-                */
-               if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) {
-                       struct vnode *tvp = p->p_tracep;
-                       p->p_tracep = NULL;
-                       p->p_traceflag = 0;
-                       vnode_rele(tvp);
-               }
-#endif
-           /*
-                * Replace the credential with a copy of itself if euid or egid change.
+                * 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_seteuid(p->p_ucred, imgp->ip_origvattr->va_uid);
+                       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);
                }
                if (imgp->ip_origvattr->va_mode & VSGID) {
-                       p->p_ucred = kauth_cred_setegid(p->p_ucred, imgp->ip_origvattr->va_gid);
+                       p->p_ucred = kauth_cred_setresgid(p->p_ucred, KAUTH_GID_NONE, imgp->ip_origvattr->va_gid, imgp->ip_origvattr->va_gid);
                }
 
+#if CONFIG_MACF
+               /* 
+                * XXXMAC: In FreeBSD, we set P_SUGID on a MAC transition
+                * to protect against debuggers being attached by an 
+                * insufficiently privileged process onto the result of
+                * a transition to a more privileged credential.  This is
+                * too conservative on FreeBSD, but we need to do
+                * something similar here, or risk vulnerability.
+                *
+                * Before we make 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 && !imgp->ip_no_trans) { 
+                       kauth_proc_label_update_execve(p,
+                               imgp->ip_vfs_context,
+                               imgp->ip_vp, 
+                               imgp->ip_scriptlabelp, imgp->ip_execlabelp);
+
+                       my_cred = kauth_cred_proc_ref(p);
+                       mac_task_label_update_cred(my_cred, p->task);
+                       kauth_cred_unref(&my_cred);
+               }
+#endif
                /*
-                * Have mach reset the task port.  We don't want
-                * anyone who had the task port before a setuid
-                * exec to be able to access/control the task
-                * after.
+                * 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.
                 */
-               if (current_task() == p->task)
+               if (current_task() == p->task) {
                        ipc_task_reset(p->task);
+                       ipc_thread_reset(current_thread());
+               }
 
-               p->p_flag |= P_SUGID;
+               /*
+                * If 'is_member' 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.  So we don't set the
+                * P_SUGID on the basis of simply running this code.
+                */
+               if (!is_member)
+                       OSBitOrAtomic(P_SUGID, (UInt32 *)&p->p_flag);
 
                /* Cache the vnode for /dev/null the first time around */
                if (dev_null == NULLVP) {
@@ -1479,7 +2675,7 @@ exec_handle_sugid(struct image_params *imgp)
                                if (p->p_fd->fd_ofiles[i] != NULL)
                                        continue;
 
-                               if ((error = falloc(p, &fp, &indx)) != 0)
+                               if ((error = falloc(p, &fp, &indx, imgp->ip_vfs_context)) != 0)
                                        continue;
 
                                if ((error = vnode_ref_ext(dev_null, FREAD)) != 0) {
@@ -1493,7 +2689,7 @@ exec_handle_sugid(struct image_params *imgp)
                                fp->f_fglob->fg_data = (caddr_t)dev_null;
                                
                                proc_fdlock(p);
-                               *fdflags(p, indx) &= ~UF_RESERVED;
+                               procfdtbl_releasefd(p, indx, NULL);
                                fp_drop(p, indx, fp, 1);
                                proc_fdunlock(p);
                        }
@@ -1520,164 +2716,217 @@ exec_handle_sugid(struct image_params *imgp)
        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
+ *             user_stack              Address to set stack for process to
+ *             customstack             FALSE if no custom stack in binary
+ *             map                     Address map in which to allocate the
+ *                                     new stack, if 'customstack' is FALSE
+ *
+ * Returns:    KERN_SUCCESS            Stack successfully created
+ *             !KERN_SUCCESS           Mach failure code
+ */
 static kern_return_t
 create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack,
-                       struct proc *p)
+                       proc_t p)
 {
-       mach_vm_size_t  size;
-       mach_vm_offset_t addr;
+       mach_vm_size_t          size, prot_size;
+       mach_vm_offset_t        addr, prot_addr;
+       kern_return_t           kr;
 
+       proc_lock(p);
        p->user_stack = user_stack;
+       proc_unlock(p);
+
        if (!customstack) {
-               size = mach_vm_round_page(unix_stack_size(p));
+               /*
+                * 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.
+                */
+               size = mach_vm_round_page(MAXSSIZ);
+#if STACK_GROWTH_UP
+               addr = mach_vm_trunc_page(user_stack);
+#else  /* STACK_GROWTH_UP */
                addr = mach_vm_trunc_page(user_stack - size);
-               return (mach_vm_allocate(map, &addr, size,
+#endif /* STACK_GROWTH_UP */
+               kr = mach_vm_allocate(map, &addr, size,
                                        VM_MAKE_TAG(VM_MEMORY_STACK) |
-                                       VM_FLAGS_FIXED));
-       } else
-               return(KERN_SUCCESS);
+                                     VM_FLAGS_FIXED);
+               if (kr != KERN_SUCCESS) {
+                       return kr;
+               }
+               /*
+                * And prevent access to what's above the current stack
+                * size limit for this process.
+                */
+               prot_addr = addr;
+#if STACK_GROWTH_UP
+               prot_addr += unix_stack_size(p);
+#endif /* STACK_GROWTH_UP */
+               prot_addr = mach_vm_round_page(prot_addr);
+               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";
-static const char *    other_init = "/sbin/mach_init";
-
-char           init_args[128] = "";
 
 struct execve_args     init_exec_args;
-int            init_attempts = 0;
-
 
+/*
+ * 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(struct proc *p)
+load_init_program(proc_t p)
 {
        vm_offset_t     init_addr;
+       int             argc = 0;
        char            *argv[3];
        int                     error;
        register_t      retval[2];
 
-       error = 0;
-
-       /* 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)) {
-                       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));
-               }
-
-               init_attempts++;
-
-               if (error) {
-                       printf("Load of %s failed, errno %d\n",
-                                       init_program_name, error);
-                       error = 0;
-                       boothowto |= RB_INITNAME;
-                       continue;
-               }
+       /*
+        * Copy out program name.
+        */
 
-               /*
-                *      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++;
 
-               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);
 
-               (void) copyout((caddr_t) init_program_name,
-                               CAST_USER_ADDR_T(init_addr),
-                               (unsigned) sizeof(init_program_name)+1);
+       argv[argc++] = (char *) init_addr;
+       init_addr += sizeof(init_program_name);
+       init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
 
-               argv[0] = (char *) 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.
-                */
+       /*
+        * 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";
 
-               (void) copyout((caddr_t) init_args,
-                               CAST_USER_ADDR_T(init_addr),
-                               (unsigned) sizeof(init_args));
+               copyout(init_args, CAST_USER_ADDR_T(init_addr),
+                       strlen(init_args));
 
-               argv[1] = (char *) init_addr;
-               init_addr += sizeof(init_args);
+               argv[argc++] = (char *)init_addr;
+               init_addr += strlen(init_args);
                init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);
 
-               /*
-                *      Null-end the argument list
-                */
+       }
 
-               argv[2] = (char *) 0;
-               
-               /*
-                *      Copy out the argument list.
-                */
-               
-               (void) copyout((caddr_t) argv,
-                               CAST_USER_ADDR_T(init_addr),
-                               (unsigned) sizeof(argv));
+       /*
+        * Null-end the argument list
+        */
+       argv[argc] = NULL;
+       
+       /*
+        * 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.
-                */
+       /*
+        * 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);
+       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);
-       } while (error);
+       error = execve(p,&init_exec_args,retval);
+       if (error)
+               panic("Process 1 exec of %s failed, errno %d\n",
+                     init_program_name, error);
 }
 
 /*
- * Convert a load_return_t to an errno.
+ * 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:
-           default:
-               return EBADEXEC;
+       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:
+       default:
+               return EBADEXEC;
        }
 }
 
@@ -1691,8 +2940,36 @@ load_return_to_errno(load_return_t lrtn)
 extern semaphore_t execve_semaphore;
 
 /*
- * 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.
+ * 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_alloc(struct image_params *imgp)
@@ -1721,6 +2998,19 @@ execargs_alloc(struct image_params *imgp)
        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)
 {
@@ -1743,3 +3033,38 @@ execargs_free(struct image_params *imgp)
                return (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);
+               }
+       }       
+
+}
+