[apple/xnu.git] / bsd / kern / kern_exec.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Mach Operating System
 * Copyright (c) 1987 Carnegie-Mellon University
 * All rights reserved.  The CMU software License Agreement specifies
 * the terms and conditions for use and redistribution.
 */
 
#include <cputypes.h>

/*-
 * Copyright (c) 1982, 1986, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      from: @(#)kern_exec.c   8.1 (Berkeley) 6/10/93
 */
#include <machine/reg.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/buf.h>
#include <sys/socketvar.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/mount.h>
#include <sys/vnode.h>          
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/acct.h>
#include <sys/exec.h>
#include <sys/kdebug.h>
#include <sys/signal.h>
#include <sys/aio_kern.h>

#include <bsm/audit_kernel.h>

#include <mach/vm_param.h>

#include <vm/vm_map.h>

extern vm_map_t vm_map_switch(vm_map_t    map); /* XXX */

#include <vm/vm_kern.h>
#include <vm/vm_shared_memory_server.h>

#include <kern/thread.h>
#include <kern/task.h>

#include <kern/ast.h>
#include <kern/mach_loader.h>
#include <mach-o/fat.h>
#include <mach-o/loader.h>
#include <machine/vmparam.h>
#if KTRACE   
#include <sys/ktrace.h>
#include <sys/ubc.h>
#endif

int     app_profile = 0;

extern vm_map_t bsd_pageable_map;

#define ROUND_PTR(type, addr)   \
        (type *)( ( (unsigned)(addr) + 16 - 1) \
                  & ~(16 - 1) )

static int load_return_to_errno(load_return_t lrtn);
int execve(struct proc *p, struct execve_args *uap, register_t *retval);
static int execargs_alloc(vm_offset_t *addrp);
static int execargs_free(vm_offset_t addr);

int
execv(p, args, retval)
        struct proc *p;
        void *args;
        int *retval;
{
        ((struct execve_args *)args)->envp = NULL;
        return (execve(p, args, retval));
}

extern char classichandler[32];
extern long classichandler_fsid;
extern long classichandler_fileid;

/*
 * Helper routine to get rid of a loop in execve.  Given a pointer to
 * something for the arg list (which might be in kernel space or in user
 * space), copy it into the kernel buffer at the currentWritePt.  This code
 * does the proper thing to get the data transferred.
 * bytesWritten, currentWritePt, and bytesLeft are kept up-to-date.
 */

static int copyArgument(char *argument, int pointerInKernel,
                        int *bytesWritten,char **currentWritePt,
                        int *bytesLeft){
        int error = 0;
        do {
                size_t len = 0;
                if (*bytesLeft <= 0) {
                        error = E2BIG;
                        break;
                }
                if (pointerInKernel == UIO_SYSSPACE) {
                        error = copystr(argument, *currentWritePt, (unsigned)*bytesLeft, &len);
                } else  {
               /*
                * pointer in kernel == UIO_USERSPACE
                * Copy in from user space.
                */ 
                  error = copyinstr((caddr_t)argument, *currentWritePt, (unsigned)*bytesLeft,
                            &len);
                }
                *currentWritePt += len;
                *bytesWritten += len;
                *bytesLeft -= len;
        } while (error == ENAMETOOLONG);
        return error;
}

/* ARGSUSED */
int
execve(p, uap, retval)
        register struct proc *p;
        register struct execve_args *uap;
        register_t *retval;
{
        register struct ucred *cred = p->p_ucred;
        register struct filedesc *fdp = p->p_fd;
        int nc;
        char *cp;
        int na, ne, ucp, ap, cc;
        unsigned len;
        int executingInterpreter=0;

        int executingClassic=0;
        char binaryWithClassicName[sizeof(p->p_comm)] = {0};
        char *execnamep;
        struct vnode *vp;
        struct vattr vattr;
        struct vattr origvattr;
        vm_offset_t execargs;
        struct nameidata nd;
        struct ps_strings ps;
#define SHSIZE  512
        /* Argument(s) to an interpreter.  If we're executing a shell
         * script, the name (#!/bin/csh) is allowed to be followed by
         * arguments.  cfarg holds these arguments.
         */
        char cfarg[SHSIZE];
        boolean_t               is_fat;
        kern_return_t           ret;
        struct mach_header      *mach_header;
        struct fat_header       *fat_header;
        struct fat_arch         fat_arch;
        load_return_t           lret;
        load_result_t           load_result;
        struct uthread          *uthread;
        vm_map_t old_map;
        vm_map_t map;
        int i;
        boolean_t                               clean_regions = FALSE;
        shared_region_mapping_t shared_region = NULL;
    shared_region_mapping_t initial_region = NULL;

        union {
                /* #! and name of interpreter */
                char                    ex_shell[SHSIZE];
                /* Mach-O executable */
                struct mach_header      mach_header;
                /* Fat executable */
                struct fat_header       fat_header;
                char    pad[512];
        } exdata;
        int resid, error;
        char *savedpath;
        int savedpathlen = 0;
        vm_offset_t *execargsp;
        char *cpnospace;
        task_t  task;
        task_t new_task;
        thread_act_t thr_act;
        int numthreads;
        int vfexec=0;
        unsigned long arch_offset =0;
        unsigned long arch_size = 0;
        char            *ws_cache_name = NULL;  /* used for pre-heat */

        /*
         * XXXAUDIT: Currently, we only audit the pathname of the binary.
         * There may also be poor interaction with dyld.
         */

        cfarg[0] = '\0'; /* initialize to null value. */
        task = current_task();
        thr_act = current_act();
        uthread = get_bsdthread_info(thr_act);

        if (uthread->uu_flag & P_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(EOPNOTSUPP);
                        }
                }
        }

        error = execargs_alloc(&execargs);
        if (error)
                return(error);

        savedpath = (char *)execargs;

        /*
         * To support new app package launching for Mac OS X, the dyld
         * needs the first argument to execve() stored on the user stack.
         * Copyin the "path" at the begining of the "execargs" buffer
         * allocated above.
         *
         * We have to do this before namei() because in case of
         * symbolic links, namei() would overwrite the original "path".
         * In case the last symbolic link resolved was a relative pathname
         * we would lose the original "path", which could be an
         * absolute pathname. This might be unacceptable for dyld.
         */
        /* XXX We could optimize to avoid copyinstr in the namei() */

        /*
         * XXXAUDIT: Note: the double copyin introduces an audit
         * race.  To correct this race, we must use a single
         * copyin().
         */
        
        error = copyinstr(uap->fname, savedpath,
                                MAXPATHLEN, (size_t *)&savedpathlen);
        if (error) {
                execargs_free(execargs);
                return(error);
        }
        /*
         * copyinstr will put in savedpathlen, the count of
         * characters (including NULL) in the path.
         * No app profiles under chroot
         */

        if((fdp->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 */
                ws_cache_name = savedpath + savedpathlen;
                while (ws_cache_name[0] != '/') {
                        if(ws_cache_name == savedpath) {
                                ws_cache_name--;
                                break;
                        }
                        ws_cache_name--;
                }
                ws_cache_name++;
        }

        /* Save the name aside for future use */
        execargsp = (vm_offset_t *)((char *)(execargs) + savedpathlen);
        
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | SAVENAME | AUDITVNPATH1,
                                        UIO_USERSPACE, uap->fname, p);
        error = namei(&nd);
        if (error)
                goto bad1;
        vp = nd.ni_vp;
        VOP_LEASE(vp, p, p->p_ucred, LEASE_READ);

        if ((error = VOP_GETATTR(vp, &origvattr, p->p_ucred, p)))
                goto bad;

        /* Check mount point */
        if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
                error = EACCES;
                goto bad;
        }

        if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED))
                origvattr.va_mode &= ~(VSUID | VSGID);
                
        *(&vattr) = *(&origvattr);

again:
        error = check_exec_access(p, vp, &vattr);
        if (error)
                goto bad;

        /*
         * Read in first few bytes of file for segment sizes, magic number:
         *      407 = plain executable
         *      410 = RO text
         *      413 = demand paged RO text
         * Also an ASCII line beginning with #! is
         * the file name of a ``shell'' and arguments may be prepended
         * to the argument list if given here.
         *
         * SHELL NAMES ARE LIMITED IN LENGTH.
         *
         * ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
         * THE ASCII LINE.
         */

        exdata.ex_shell[0] = '\0';      /* for zero length files */

        error = vn_rdwr(UIO_READ, vp, (caddr_t)&exdata, sizeof (exdata), 0,
                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);

        if (error)
                goto bad;

#ifndef lint
        if (resid > sizeof(exdata) - min(sizeof(exdata.mach_header),
                                         sizeof(exdata.fat_header))
            && exdata.ex_shell[0] != '#') {
                error = ENOEXEC;
                goto bad;
        }
#endif /* lint */
        mach_header = &exdata.mach_header;
        fat_header = &exdata.fat_header;
        if ((mach_header->magic == MH_CIGAM) &&
            (classichandler[0] == 0)) {
                error = EBADARCH;
                goto bad;
        } else if ((mach_header->magic == MH_MAGIC) || 
               (mach_header->magic == MH_CIGAM)) {
            is_fat = FALSE;
        } else if ((fat_header->magic == FAT_MAGIC) ||
                       (fat_header->magic == FAT_CIGAM)) {
            is_fat = TRUE;
        } else {
          /* If we've already redirected once from an interpreted file
           * to an interpreter, don't permit the second time.
           */
                if (exdata.ex_shell[0] != '#' ||
                    exdata.ex_shell[1] != '!' ||
                    executingInterpreter) {
                        error = ENOEXEC;
                        goto bad;
                }
                if (executingClassic == 1) {
                  error = EBADARCH;
                  goto bad;
                }
                cp = &exdata.ex_shell[2];               /* skip "#!" */
                while (cp < &exdata.ex_shell[SHSIZE]) {
                        if (*cp == '\t')                /* convert all tabs to spaces */
                                *cp = ' ';
                        else if (*cp == '\n' || *cp == '#') {
                                *cp = '\0';                     /* trunc the line at nl or comment */

                                /* go back and remove the spaces before the /n or # */
                                /* todo: do we have to do this if we fix the passing of args to shells ? */
                                if ( cp != &exdata.ex_shell[2] ) {
                                        do {
                                                if ( *(cp-1) != ' ')
                                                        break;
                                                *(--cp) = '\0';
                                        } while ( cp != &exdata.ex_shell[2] );
                                }
                                break;
                        }
                        cp++;
                }
                if (*cp != '\0') {
                        error = ENOEXEC;
                        goto bad;
                }
                cp = &exdata.ex_shell[2];
                while (*cp == ' ')
                        cp++;
                execnamep = cp;
                while (*cp && *cp != ' ')
                        cp++;
                cfarg[0] = '\0';
                cpnospace = cp;
                if (*cp) {
                        *cp++ = '\0';
                        while (*cp == ' ')
                                cp++;
                        if (*cp)
                                bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
                }

                /*
                 * Support for new app package launching for Mac OS X.
                 * We are about to retry the execve() by changing the path to the
                 * interpreter name. Need to re-initialize the savedpath and
                 * savedpathlen. +1 for NULL.
                 */
                savedpathlen = (cpnospace - execnamep + 1);
                error = copystr(execnamep, savedpath,
                                        savedpathlen, (size_t *)&savedpathlen);
                if (error)
                        goto bad;

                /* Save the name aside for future use */
                execargsp = (vm_offset_t *)((char *)(execargs) + savedpathlen);

                executingInterpreter= 1;
                vput(vp);
                nd.ni_cnd.cn_nameiop = LOOKUP;
                nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) |
                                                (FOLLOW | LOCKLEAF | SAVENAME);
                nd.ni_segflg = UIO_SYSSPACE;
                nd.ni_dirp = execnamep;
                if ((error = namei(&nd)))
                        goto bad1;
                vp = nd.ni_vp;
                VOP_LEASE(vp, p, cred, LEASE_READ);
                if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p)))
                        goto bad;
                goto again;
        }

        /*
         * Collect arguments on "file" in swap space.
         */
        na = 0;
        ne = 0;
        nc = 0;
        cc = 0;
        /*
         * Support for new app package launching for Mac OS X allocates
         * the "path" at the begining.
         * execargs get allocated after that
         */
        cp = (char *) execargsp;        /* running pointer for copy */
        /*
         * size of execargs less sizeof "path",
         * a pointer to "path" and a NULL poiter
         */
        cc = NCARGS - savedpathlen - 2*NBPW;
        /*
         * Copy arguments into file in argdev area.
         */


        /*
         * If we have a fat file, find "our" executable.
         */
        if (is_fat) {
                /*
                 * Look up our architecture in the fat file.
                 */
                lret = fatfile_getarch_affinity(vp,(vm_offset_t)fat_header, &fat_arch,
                                                (p->p_flag & P_AFFINITY));
                if (lret != LOAD_SUCCESS) {
                        error = load_return_to_errno(lret);
                        goto bad;
                }
                /* Read the Mach-O header out of it */
                error = vn_rdwr(UIO_READ, vp, (caddr_t)&exdata.mach_header,
                                sizeof (exdata.mach_header),
                                fat_arch.offset,
                                UIO_SYSSPACE, (IO_UNIT|IO_NODELOCKED), cred, &resid, p);

                if (error) {
                        goto bad;
                }

                /* Did we read a complete header? */
                if (resid) {
                        error = EBADEXEC;
                        goto bad;
                }

                /* Is what we found a Mach-O executable */
                if ((mach_header->magic != MH_MAGIC) &&
                    (mach_header->magic != MH_CIGAM)) {
                        error = ENOEXEC;
                        goto bad;
                }

                arch_offset = fat_arch.offset;
                arch_size = fat_arch.size;
        } else {
                /*
                 *      Load the Mach-O file.
                 */
                arch_offset = 0;
                arch_size = (u_long)vattr.va_size;
        }

        if ( ! check_cpu_subtype(mach_header->cpusubtype) ) {
                error = EBADARCH;
                goto bad;
        }

        if (mach_header->magic == MH_CIGAM) {

                int classicBinaryLen = nd.ni_cnd.cn_namelen;
                if (classicBinaryLen > MAXCOMLEN)
                classicBinaryLen = MAXCOMLEN;
                bcopy((caddr_t)nd.ni_cnd.cn_nameptr,
                                (caddr_t)binaryWithClassicName, 
                                (unsigned)classicBinaryLen);
                binaryWithClassicName[classicBinaryLen] = '\0';
                executingClassic = 1;

                vput(vp); /* cleanup? */
                nd.ni_cnd.cn_nameiop = LOOKUP;

                nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) |
                /*      (FOLLOW | LOCKLEAF | SAVENAME) */
                (LOCKLEAF | SAVENAME);
                 nd.ni_segflg = UIO_SYSSPACE;

                nd.ni_dirp = classichandler;
                if ((error = namei(&nd)) != 0) {
                        error = EBADARCH;
                        goto bad1;
                }
                vp = nd.ni_vp;

                VOP_LEASE(vp,p,cred,LEASE_READ);
                if ((error = VOP_GETATTR(vp,&vattr,p->p_ucred,p))) {
                        goto bad;
                }
                goto again;
        }

        if (uap->argp != NULL) {
          /* geez -- why would argp ever be NULL, and why would we proceed? */
          
          /* First, handle any argument massaging */
          if (executingInterpreter && executingClassic) {
            error = copyArgument(classichandler,UIO_SYSSPACE,&nc,&cp,&cc);
            na++;
            if (error) goto bad;
            
            /* Now name the interpreter. */
            error = copyArgument(savedpath,UIO_SYSSPACE,&nc,&cp,&cc);
            na++;
            if (error) goto bad;

            /*
             * if we're running an interpreter, as we'd be passing the
             * command line executable as an argument to the interpreter already.
             * Doing "execve("myShellScript","bogusName",arg1,arg2,...)
             * probably shouldn't ever let bogusName be seen by the shell
             * script.
             */

            if (cfarg[0]) {
              error = copyArgument(cfarg,UIO_SYSSPACE,&nc,&cp,&cc);
              na++;
              if (error) goto bad;
            }

            char* originalExecutable = uap->fname;
            error = copyArgument(originalExecutable,UIO_USERSPACE,&nc,&cp,&cc);
            na++;
            /* remove argv[0] b/c we've already placed it at */
            /* this point */
            uap->argp++;
            if (error) goto bad;

            /* and continue with rest of the arguments. */
          } else if (executingClassic) {
            error = copyArgument(classichandler,UIO_SYSSPACE,&nc,&cp,&cc);
            na++;
            if (error) goto bad;
            
            char* originalExecutable = uap->fname;
            error = copyArgument(originalExecutable,UIO_USERSPACE,&nc,&cp,&cc);
            if (error) goto bad;
            uap->argp++;
            na++;

            /* and rest of arguments continue as before. */
          } else if (executingInterpreter) {
            char *actualExecutable = nd.ni_cnd.cn_nameptr;
            error = copyArgument(actualExecutable,UIO_SYSSPACE,&nc,&cp,&cc);
            na++;
            /* remove argv[0] b/c we just placed it in the arg list. */
            uap->argp++;
            if (error) goto bad;
            /* Copy the argument in the interpreter first line if there
             * was one. 
             */
            if (cfarg[0]) {
              error = copyArgument(cfarg,UIO_SYSSPACE,&nc,&cp,&cc);
              na++;
              if (error) goto bad;
            }
            
            /* copy the name of the file being interpreted, gotten from
             * the structures passed in to execve.
             */
            error = copyArgument(uap->fname,UIO_USERSPACE,&nc,&cp,&cc);
            na++;
          }
          /* Now, get rest of arguments */
          while (uap->argp != NULL) {
            char* userArgument = (char*)fuword((caddr_t) uap->argp);
            uap->argp++;
            if (userArgument == NULL) {
              break;
            } else if ((int)userArgument == -1) {
              /* Um... why would it be -1? */
              error = EFAULT;
              goto bad;
            }
            error = copyArgument(userArgument, UIO_USERSPACE,&nc,&cp,&cc);
            if (error) goto bad;
            na++;
          }      
          /* Now, get the environment */
          while (uap->envp != NULL) {
            char *userEnv = (char*) fuword((caddr_t) uap->envp);
            uap->envp++;
            if (userEnv == NULL) {
              break;
            } else if ((int)userEnv == -1) {
              error = EFAULT;
              goto bad;
            }
            error = copyArgument(userEnv,UIO_USERSPACE,&nc,&cp,&cc);
            if (error) goto bad;
            na++;
            ne++;
          }
        }

        /* make sure there are nulls are the end!! */
        {
                int     cnt = 3;
                char *mp = cp;

                while ( cnt-- )
                        *mp++ = '\0';   
        }

        /* and round up count of bytes written to next word. */
        nc = (nc + NBPW-1) & ~(NBPW-1);

        if (vattr.va_fsid == classichandler_fsid &&
                vattr.va_fileid == classichandler_fileid) {
                executingClassic = 1;
        }

        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);
                task = new_task;
                map = get_task_map(new_task);
                result = thread_create(new_task, &thr_act);
                if (result != KERN_SUCCESS)
                printf("execve: thread_create failed. Code: 0x%x\n", result);
                uthread = get_bsdthread_info(thr_act);
        } else {
                map = VM_MAP_NULL;
        }

        /*
         *      Load the Mach-O file.
         */
        VOP_UNLOCK(vp, 0, p);   /* XXX */
        if(ws_cache_name) {
                tws_handle_startup_file(task, cred->cr_uid, 
                        ws_cache_name, vp, &clean_regions);
        }

        vm_get_shared_region(task, &initial_region);
    int parentIsClassic = (p->p_flag & P_CLASSIC);
        struct vnode *rootDir = p->p_fd->fd_rdir;

        if ((parentIsClassic && !executingClassic) ||
                (!parentIsClassic && executingClassic)) {
                shared_region = lookup_default_shared_region(
                                (int)rootDir,
                                (executingClassic ?
                                CPU_TYPE_POWERPC :
                                machine_slot[cpu_number()].cpu_type));
                if (shared_region == NULL) {
                        shared_region_mapping_t old_region;
                        shared_region_mapping_t new_region;
                        vm_get_shared_region(current_task(), &old_region);
                        /* grrrr... this sets current_task(), not task
                        * -- they're different (usually)
                        */
                        shared_file_boot_time_init(
                                (int)rootDir,
                                (executingClassic ?
                                CPU_TYPE_POWERPC :
                                machine_slot[cpu_number()].cpu_type));
                        if ( current_task() != task ) {
                                vm_get_shared_region(current_task(),&new_region);
                                vm_set_shared_region(task,new_region);
                                vm_set_shared_region(current_task(),old_region);
                        }
                } else {
                        vm_set_shared_region(task, shared_region);
                }
                shared_region_mapping_dealloc(initial_region);
        }
        
        lret = load_machfile(vp, mach_header, arch_offset,
                arch_size, &load_result, thr_act, map, clean_regions);

        if (lret != LOAD_SUCCESS) {
                error = load_return_to_errno(lret);
                vrele(vp);
                vp = NULL;
                goto badtoolate;
        }

        /* load_machfile() maps the vnode */
        ubc_map(vp);

        /*
         * deal with set[ug]id.
         */
        p->p_flag &= ~P_SUGID;
        if (((origvattr.va_mode & VSUID) != 0 &&
            p->p_ucred->cr_uid != origvattr.va_uid)
            || (origvattr.va_mode & VSGID) != 0 &&
            p->p_ucred->cr_gid != origvattr.va_gid) {
                p->p_ucred = crcopy(cred);
#if KTRACE
                /*
                 * If process is being ktraced, turn off - unless
                 * root set it.
                 */
                if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) {
                        struct vnode *tvp = p->p_tracep;
                        p->p_tracep = NULL;
                        p->p_traceflag = 0;

                        if (UBCINFOEXISTS(tvp))
                                ubc_rele(tvp);
                        vrele(tvp);
                }
#endif
                if (origvattr.va_mode & VSUID)
                        p->p_ucred->cr_uid = origvattr.va_uid;
                if (origvattr.va_mode & VSGID)
                        p->p_ucred->cr_gid = origvattr.va_gid;

                /*
                 * 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.
                 */
                ipc_task_reset(task);

                p->p_flag |= P_SUGID;

                /* Radar 2261856; setuid security hole fix */
                /* Patch from OpenBSD: A. Ramesh */
                /*
                 * XXX For setuid processes, attempt to ensure that
                 * stdin, stdout, and stderr are already allocated.
                 * We do not want userland to accidentally allocate
                 * descriptors in this range which has implied meaning
                 * to libc.
                 */
                for (i = 0; i < 3; i++) {
                        extern struct fileops vnops;
                        struct nameidata nd1;
                        struct file *fp;
                        int indx;

                        if (p->p_fd->fd_ofiles[i] == NULL) {
                                if ((error = falloc(p, &fp, &indx)) != 0)
                                        continue;
                                NDINIT(&nd1, LOOKUP, FOLLOW, UIO_SYSSPACE,
                                    "/dev/null", p);
                                if ((error = vn_open(&nd1, FREAD, 0)) != 0) {
                                        ffree(fp);
                                        p->p_fd->fd_ofiles[indx] = NULL;
                                        break;
                                }
                                fp->f_flag = FREAD;
                                fp->f_type = DTYPE_VNODE;
                                fp->f_ops = &vnops;
                                fp->f_data = (caddr_t)nd1.ni_vp;
                                VOP_UNLOCK(nd1.ni_vp, 0, p);
                        }
                }
        }
        p->p_cred->p_svuid = p->p_ucred->cr_uid;
        p->p_cred->p_svgid = p->p_ucred->cr_gid;
        set_security_token(p);

        KNOTE(&p->p_klist, NOTE_EXEC);

        if (!vfexec && (p->p_flag & P_TRACED))
                psignal(p, SIGTRAP);

        if (error) {
                vrele(vp);
                vp = NULL;
                goto badtoolate;
        }
        VOP_LOCK(vp,  LK_EXCLUSIVE | LK_RETRY, p); /* XXX */
        vput(vp);
        vp = NULL;
        
        if (load_result.unixproc &&
                create_unix_stack(get_task_map(task),
                                  load_result.user_stack, load_result.customstack, p)) {
                error = load_return_to_errno(LOAD_NOSPACE);
                goto badtoolate;
        }

        if (vfexec) {
                uthread->uu_ar0 = (void *)get_user_regs(thr_act);
        }

        /*
         * Copy back arglist if necessary.
         */


        ucp = (int)p->user_stack;
        if (vfexec) {
                old_map = vm_map_switch(get_task_map(task));
        }
        if (load_result.unixproc) {
                int pathptr;
                
                ucp = ucp - nc - NBPW;  /* begining of the STRING AREA */

                /*
                 * Support for new app package launching for Mac OS X allocates
                 * the "path" at the begining of the execargs buffer.
                 * copy it just before the string area.
                 */
                len = 0;
                pathptr = ucp - ((savedpathlen + NBPW-1) & ~(NBPW-1));
                error = copyoutstr(savedpath, (caddr_t)pathptr,
                                        (unsigned)savedpathlen, (size_t *)&len);
                savedpathlen = (savedpathlen + NBPW-1) & ~(NBPW-1);

                if (error) {
                        if (vfexec)
                                vm_map_switch(old_map);
                        goto badtoolate;
                }

                /*
                 * Record the size of the arguments area so that
                 * sysctl_procargs() can return the argument area without having
                 * to parse the arguments.
                 */
                p->p_argslen = (int)p->user_stack - pathptr;
                p->p_argc = na - ne;    /* save argc for sysctl_procargs() */

                /* Save a NULL pointer below it */
                (void) suword((caddr_t)(pathptr - NBPW), 0);

                /* Save the pointer to "path" just below it */
                (void) suword((caddr_t)(pathptr - 2*NBPW), pathptr);

                /*
                 * na includes arg[] and env[].
                 * NBPW for 2 NULL one each ofter arg[argc -1] and env[n]
                 * NBPW for argc
                 * skip over saved path, NBPW for pointer to path,
                 * and NBPW for the NULL after pointer to path.
                 */
                ap = ucp - na*NBPW - 3*NBPW - savedpathlen - 2*NBPW;
#if defined(ppc)
                thread_setuserstack(thr_act, ap);       /* Set the stack */
#else
                uthread->uu_ar0[SP] = ap;
#endif
                (void) suword((caddr_t)ap, na-ne); /* argc */
                nc = 0;
                cc = 0;

                cp = (char *) execargsp;
                cc = NCARGS - savedpathlen - 2*NBPW;
                ps.ps_argvstr = (char *)ucp;    /* first argv string */
                ps.ps_nargvstr = na - ne;               /* argc */
                for (;;) {
                        ap += NBPW;
                        if (na == ne) {
                                (void) suword((caddr_t)ap, 0);
                                ap += NBPW;
                                ps.ps_envstr = (char *)ucp;
                                ps.ps_nenvstr = ne;
                        }
                        if (--na < 0)
                                break;
                        (void) suword((caddr_t)ap, ucp);
                        do {
                                error = copyoutstr(cp, (caddr_t)ucp,
                                                   (unsigned)cc, (size_t *)&len);
                                ucp += len;
                                cp += len;
                                nc += len;
                                cc -= len;
                        } while (error == ENAMETOOLONG);
                        if (error == EFAULT)
                                break;  /* bad stack - user's problem */
                }
                (void) suword((caddr_t)ap, 0);
        }
        
        if (load_result.dynlinker) {
#if defined(ppc)
                ap = thread_adjuserstack(thr_act, -4);  /* Adjust the stack */
#else
                ap = uthread->uu_ar0[SP] -= 4;
#endif
                (void) suword((caddr_t)ap, load_result.mach_header);
        }

        if (vfexec) {
                vm_map_switch(old_map);
        }
#if defined(ppc)
        thread_setentrypoint(thr_act, load_result.entry_point); /* Set the entry point */
#elif defined(i386) 
        uthread->uu_ar0[PC] = load_result.entry_point;
#else
#error architecture not implemented!
#endif  

        /* Stop profiling */
        stopprofclock(p);

        /*
         * Reset signal state.
         */
        execsigs(p, thr_act);

        /*
         * 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 );

        /* FIXME: Till vmspace inherit is fixed: */
        if (!vfexec && p->vm_shm)
                shmexec(p);
        /* Clean up the semaphores */
        semexit(p);

        /*
         * Remember file name for accounting.
         */
        p->p_acflag &= ~AFORK;
        /* If the translated name isn't NULL, then we want to use
         * that translated name as the name we show as the "real" name.
         * Otherwise, use the name passed into exec.
         */
        if (0 != binaryWithClassicName[0]) {
                bcopy((caddr_t)binaryWithClassicName, (caddr_t)p->p_comm,
                        sizeof(binaryWithClassicName));
        } else {
                if (nd.ni_cnd.cn_namelen > MAXCOMLEN)
                        nd.ni_cnd.cn_namelen = MAXCOMLEN;
                bcopy((caddr_t)nd.ni_cnd.cn_nameptr, (caddr_t)p->p_comm,
                        (unsigned)nd.ni_cnd.cn_namelen);
                p->p_comm[nd.ni_cnd.cn_namelen] = '\0';
        }

        {
          /* This is for kdebug */
          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)thr_act);
                  KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE,
                                        dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (unsigned int)thr_act);
          }
          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);
          }
        }

        if (executingClassic)
                p->p_flag |= P_CLASSIC | P_AFFINITY;
        else
                p->p_flag &= ~P_CLASSIC;

        /*
         * 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;
                wakeup((caddr_t)p->p_pptr);
        }

        if (vfexec && (p->p_flag & P_TRACED)) {
                        psignal_vfork(p, new_task, thr_act, SIGTRAP);
        }

badtoolate:
        if (vfexec) {
                task_deallocate(new_task);
                act_deallocate(thr_act);
                if (error)
                        error = 0;
        }
bad:
        FREE_ZONE(nd.ni_cnd.cn_pnbuf, nd.ni_cnd.cn_pnlen, M_NAMEI);
        if (vp)
                vput(vp);
bad1:
        if (execargs)
                execargs_free(execargs);
        if (!error && vfexec) {
                        vfork_return(current_act(), p->p_pptr, p, retval);
                        (void) thread_resume(thr_act);
                        return(0);
        }
        return(error);
}


#define unix_stack_size(p)      (p->p_rlimit[RLIMIT_STACK].rlim_cur)

kern_return_t
create_unix_stack(map, user_stack, customstack, p)
        vm_map_t        map;
        vm_offset_t     user_stack;
        int                     customstack;
        struct proc     *p;
{
        vm_size_t       size;
        vm_offset_t     addr;

        p->user_stack = (caddr_t)user_stack;
        if (!customstack) {
                size = round_page_64(unix_stack_size(p));
                addr = trunc_page_32(user_stack - size);
                return (vm_allocate(map, &addr, size,
                                        VM_MAKE_TAG(VM_MEMORY_STACK) | FALSE));
        } else
                return(KERN_SUCCESS);
}

#include <sys/reboot.h>

char            init_program_name[128] = "/sbin/mach_init\0";

char            init_args[128] = "";

struct execve_args      init_exec_args;
int             init_attempts = 0;


void
load_init_program(p)
        struct proc *p;
{
        vm_offset_t     init_addr;
        int             *old_ap;
        char            *argv[3];
        int             error;
        register_t retval[2];
        struct uthread * ut;

        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)) {
                        static char other_init[] = "/etc/mach_init";
                        printf("Load of %s, errno %d, trying %s\n",
                                init_program_name, error, other_init);
                        error = 0;
                        bcopy(other_init, init_program_name,
                                                        sizeof(other_init));
                }

                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.
                 */

                init_addr = VM_MIN_ADDRESS;
                (void) vm_allocate(current_map(), &init_addr,
                                   PAGE_SIZE, TRUE);
                if (init_addr == 0)
                        init_addr++;
                (void) copyout((caddr_t) init_program_name,
                                (caddr_t) (init_addr),
                                (unsigned) sizeof(init_program_name)+1);

                argv[0] = (char *) init_addr;
                init_addr += sizeof(init_program_name);
                init_addr = (vm_offset_t)ROUND_PTR(char, init_addr);

                /*
                 *      Put out first (and only) argument, similarly.
                 *      Assumes everything fits in a page as allocated
                 *      above.
                 */

                (void) copyout((caddr_t) init_args,
                                (caddr_t) (init_addr),
                                (unsigned) sizeof(init_args));

                argv[1] = (char *) init_addr;
                init_addr += sizeof(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,
                                (caddr_t) (init_addr),
                                (unsigned) sizeof(argv));

                /*
                 *      Set up argument block for fake call to execve.
                 */

                init_exec_args.fname = argv[0];
                init_exec_args.argp = (char **) init_addr;
                init_exec_args.envp = 0;
                
                /* So that mach_init task 
                 * is set with uid,gid 0 token 
                 */
                set_security_token(p);

                error = execve(p,&init_exec_args,retval);
        } while (error);
}

/*
 * Convert a load_return_t to an errno.
 */
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;
        }
}

/*
 * exec_check_access()
 */
int
check_exec_access(p, vp, vap)
        struct proc  *p;
        struct vnode *vp;
        struct vattr *vap;
{
        int flag;
        int error;

        if (error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p))
                return (error);
        flag = p->p_flag;
        if (flag & P_TRACED) {
                if (error = VOP_ACCESS(vp, VREAD, p->p_ucred, p))
                        return (error);
        }
        if (vp->v_type != VREG ||
            (vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)
                return (EACCES);
        return (0);
}

#include <mach/mach_types.h>
#include <mach/vm_prot.h>
#include <mach/semaphore.h>
#include <mach/sync_policy.h>
#include <kern/clock.h>
#include <mach/kern_return.h>

extern semaphore_t execve_semaphore;

static int
execargs_alloc(addrp)
        vm_offset_t     *addrp;
{
        kern_return_t kret;

        kret = semaphore_wait(execve_semaphore);
        if (kret != KERN_SUCCESS)
                switch (kret) {
                default:
                        return (EINVAL);
                case KERN_INVALID_ADDRESS:
                case KERN_PROTECTION_FAILURE:
                        return (EACCES);
                case KERN_ABORTED:
                case KERN_OPERATION_TIMED_OUT:
                        return (EINTR);
                }

        kret = kmem_alloc_pageable(bsd_pageable_map, addrp, NCARGS);
        if (kret != KERN_SUCCESS) {
                semaphore_signal(execve_semaphore);
                return (ENOMEM);
        }
        return (0);
}

static int
execargs_free(addr)
        vm_offset_t     addr;
{
        kern_return_t kret;

        kmem_free(bsd_pageable_map, addr, NCARGS);

        kret = semaphore_signal(execve_semaphore);
        switch (kret) { 
        case KERN_INVALID_ADDRESS:
        case KERN_PROTECTION_FAILURE:
                return (EINVAL);
        case KERN_ABORTED:
        case KERN_OPERATION_TIMED_OUT:
                return (EINTR);
        case KERN_SUCCESS:
                return(0);
        default:
                return (EINVAL);
        }
}