2 * Copyright (c) 1993, David Greenman
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/kern/kern_exec.c,v 1.107.2.15 2002/07/30 15:40:46 nectar Exp $
27 * $DragonFly: src/sys/kern/kern_exec.c,v 1.61 2007/07/30 17:41:23 pavalos Exp $
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/sysproto.h>
33 #include <sys/kernel.h>
34 #include <sys/mount.h>
35 #include <sys/filedesc.h>
36 #include <sys/fcntl.h>
39 #include <sys/imgact.h>
40 #include <sys/imgact_elf.h>
41 #include <sys/kern_syscall.h>
43 #include <sys/malloc.h>
45 #include <sys/ktrace.h>
46 #include <sys/signalvar.h>
47 #include <sys/pioctl.h>
48 #include <sys/nlookup.h>
49 #include <sys/sfbuf.h>
50 #include <sys/sysent.h>
52 #include <sys/sysctl.h>
53 #include <sys/vnode.h>
54 #include <sys/vmmeter.h>
56 #include <sys/libkern.h>
59 #include <vm/vm_param.h>
62 #include <vm/vm_page.h>
63 #include <vm/vm_map.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_extern.h>
66 #include <vm/vm_object.h>
67 #include <vm/vm_pager.h>
72 #include <sys/thread2.h>
74 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
75 MALLOC_DEFINE(M_EXECARGS, "exec-args", "Exec arguments");
77 static register_t *exec_copyout_strings (struct image_params *);
79 /* XXX This should be vm_size_t. */
80 static u_long ps_strings = PS_STRINGS;
81 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
83 /* XXX This should be vm_size_t. */
84 static u_long usrstack = USRSTACK;
85 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
87 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
88 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
89 &ps_arg_cache_limit, 0, "");
92 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
94 void print_execve_args(struct image_args *args);
95 int debug_execve_args = 0;
96 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args,
100 * Exec arguments object cache
102 static struct objcache *exec_objcache;
106 exec_objcache_init(void *arg __unused)
108 exec_objcache = objcache_create_mbacked(
109 M_EXECARGS, PATH_MAX + ARG_MAX,
110 16, /* up to this many objects */
111 2, /* minimal magazine capacity */
114 SYSINIT(exec_objcache, SI_BOOT2_MACHDEP, SI_ORDER_ANY, exec_objcache_init, 0);
117 * stackgap_random specifies if the stackgap should have a random size added
118 * to it. It must be a power of 2. If non-zero, the stack gap will be
119 * calculated as: ALIGN(karc4random() & (stackgap_random - 1)).
121 static int stackgap_random = 1024;
123 sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS)
126 new_val = stackgap_random;
127 error = sysctl_handle_int(oidp, &new_val, 0, req);
128 if (error != 0 || req->newptr == NULL)
130 if ((new_val < 0) || (new_val > 16 * PAGE_SIZE) || ! powerof2(new_val))
132 stackgap_random = new_val;
137 SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_UINT,
138 0, 0, sysctl_kern_stackgap, "IU", "Max random stack gap (power of 2)");
141 print_execve_args(struct image_args *args)
146 cp = args->begin_argv;
147 for (ndx = 0; ndx < args->argc; ndx++) {
148 kprintf("\targv[%d]: %s\n", ndx, cp);
149 while (*cp++ != '\0');
151 for (ndx = 0; ndx < args->envc; ndx++) {
152 kprintf("\tenvv[%d]: %s\n", ndx, cp);
153 while (*cp++ != '\0');
158 * Each of the items is a pointer to a `const struct execsw', hence the
159 * double pointer here.
161 static const struct execsw **execsw;
164 * Replace current vmspace with a new binary.
165 * Returns 0 on success, > 0 on recoverable error (use as errno).
166 * Returns -1 on lethal error which demands killing of the current
170 kern_execve(struct nlookupdata *nd, struct image_args *args)
172 struct thread *td = curthread;
173 struct lwp *lp = td->td_lwp;
174 struct proc *p = td->td_proc;
175 register_t *stack_base;
177 struct image_params image_params, *imgp;
179 int (*img_first) (struct image_params *);
181 if (debug_execve_args) {
182 kprintf("%s()\n", __func__);
183 print_execve_args(args);
187 imgp = &image_params;
190 * NOTE: P_INEXEC is handled by exec_new_vmspace() now. We make
191 * no modifications to the process at all until we get there.
193 * Note that multiple threads may be trying to exec at the same
194 * time. exec_new_vmspace() handles that too.
198 * Initialize part of the common data
203 imgp->entry_addr = 0;
205 imgp->vmspace_destroyed = 0;
206 imgp->interpreted = 0;
207 imgp->interpreter_name[0] = 0;
208 imgp->auxargs = NULL;
210 imgp->firstpage = NULL;
211 imgp->ps_strings = 0;
212 imgp->image_header = NULL;
217 * Translate the file name to a vnode. Unlock the cache entry to
218 * improve parallelism for programs exec'd in parallel.
220 if ((error = nlookup(nd)) != 0)
222 error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &imgp->vp);
223 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
224 nd->nl_flags &= ~NLC_NCPISLOCKED;
225 cache_unlock(&nd->nl_nch);
230 * Check file permissions (also 'opens' file)
232 error = exec_check_permissions(imgp);
235 goto exec_fail_dealloc;
238 error = exec_map_first_page(imgp);
241 goto exec_fail_dealloc;
243 if (debug_execve_args && imgp->interpreted) {
244 kprintf(" target is interpreted -- recursive pass\n");
245 kprintf(" interpreter: %s\n", imgp->interpreter_name);
246 print_execve_args(args);
250 * If the current process has a special image activator it
251 * wants to try first, call it. For example, emulating shell
252 * scripts differently.
255 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
256 error = img_first(imgp);
259 * If the vnode has a registered vmspace, exec the vmspace
261 if (error == -1 && imgp->vp->v_resident) {
262 error = exec_resident_imgact(imgp);
266 * Loop through the list of image activators, calling each one.
267 * An activator returns -1 if there is no match, 0 on success,
268 * and an error otherwise.
270 for (i = 0; error == -1 && execsw[i]; ++i) {
271 if (execsw[i]->ex_imgact == NULL ||
272 execsw[i]->ex_imgact == img_first) {
275 error = (*execsw[i]->ex_imgact)(imgp);
281 goto exec_fail_dealloc;
285 * Special interpreter operation, cleanup and loop up to try to
286 * activate the interpreter.
288 if (imgp->interpreted) {
289 exec_unmap_first_page(imgp);
293 error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE,
301 * Copy out strings (args and env) and initialize stack base
303 stack_base = exec_copyout_strings(imgp);
304 p->p_vmspace->vm_minsaddr = (char *)stack_base;
307 * If custom stack fixup routine present for this process
308 * let it do the stack setup. If we are running a resident
309 * image there is no auxinfo or other image activator context
310 * so don't try to add fixups to the stack.
312 * Else stuff argument count as first item on stack
314 if (p->p_sysent->sv_fixup && imgp->resident == 0)
315 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
317 suword(--stack_base, imgp->args->argc);
320 * For security and other reasons, the file descriptor table cannot
321 * be shared after an exec.
323 if (p->p_fd->fd_refcnt > 1) {
324 struct filedesc *tmp;
332 * For security and other reasons, signal handlers cannot
333 * be shared after an exec. The new proces gets a copy of the old
334 * handlers. In execsigs(), the new process will have its signals
337 if (p->p_sigacts->ps_refcnt > 1) {
338 struct sigacts *newsigacts;
340 newsigacts = (struct sigacts *)kmalloc(sizeof(*newsigacts),
341 M_SUBPROC, M_WAITOK);
342 bcopy(p->p_sigacts, newsigacts, sizeof(*newsigacts));
343 p->p_sigacts->ps_refcnt--;
344 p->p_sigacts = newsigacts;
345 p->p_sigacts->ps_refcnt = 1;
349 * For security and other reasons virtual kernels cannot be
350 * inherited by an exec. This also allows a virtual kernel
351 * to fork/exec unrelated applications.
359 /* close files on exec */
362 /* reset caught signals */
365 /* name this process - nameiexec(p, ndp) */
366 len = min(nd->nl_nch.ncp->nc_nlen, MAXCOMLEN);
367 bcopy(nd->nl_nch.ncp->nc_name, p->p_comm, len);
369 bcopy(p->p_comm, lp->lwp_thread->td_comm, MAXCOMLEN+1);
372 * mark as execed, wakeup the process that vforked (if any) and tell
373 * it that it now has its own resources back
376 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
377 p->p_flag &= ~P_PPWAIT;
378 wakeup((caddr_t)p->p_pptr);
382 * Implement image setuid/setgid.
384 * Don't honor setuid/setgid if the filesystem prohibits it or if
385 * the process is being traced.
387 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
388 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
389 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
390 (p->p_flag & P_TRACED) == 0) {
392 * Turn off syscall tracing for set-id programs, except for
393 * root. Record any set-id flags first to make sure that
394 * we do not regain any tracing during a possible block.
397 if (p->p_tracenode && suser(td) != 0) {
398 ktrdestroy(&p->p_tracenode);
401 /* Close any file descriptors 0..2 that reference procfs */
403 /* Make sure file descriptors 0..2 are in use. */
404 error = fdcheckstd(p);
406 goto exec_fail_dealloc;
408 * Set the new credentials.
411 if (attr.va_mode & VSUID)
412 change_euid(attr.va_uid);
413 if (attr.va_mode & VSGID)
414 p->p_ucred->cr_gid = attr.va_gid;
417 * Clear local varsym variables
419 varsymset_clean(&p->p_varsymset);
421 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
422 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
423 p->p_flag &= ~P_SUGID;
427 * Implement correct POSIX saved-id behavior.
429 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
430 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
432 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
433 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
437 * Store the vp for use in procfs
439 if (p->p_textvp) /* release old reference */
441 p->p_textvp = imgp->vp;
445 * Notify others that we exec'd, and clear the P_INEXEC flag
446 * as we're now a bona fide freshly-execed process.
448 KNOTE(&p->p_klist, NOTE_EXEC);
449 p->p_flag &= ~P_INEXEC;
452 * If tracing the process, trap to debugger so breakpoints
453 * can be set before the program executes.
455 STOPEVENT(p, S_EXEC, 0);
457 if (p->p_flag & P_TRACED)
460 /* clear "fork but no exec" flag, as we _are_ execing */
461 p->p_acflag &= ~AFORK;
463 /* Set values passed into the program in registers. */
464 exec_setregs(imgp->entry_addr, (u_long)(uintptr_t)stack_base,
467 /* Free any previous argument cache */
468 if (p->p_args && --p->p_args->ar_ref == 0)
469 FREE(p->p_args, M_PARGS);
472 /* Cache arguments if they fit inside our allowance */
473 i = imgp->args->begin_envv - imgp->args->begin_argv;
474 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
475 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
477 p->p_args->ar_ref = 1;
478 p->p_args->ar_length = i;
479 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i);
485 * free various allocated resources
488 exec_unmap_first_page(imgp);
496 ++mycpu->gd_cnt.v_exec;
502 * we're done here, clear P_INEXEC if we were the ones that
503 * set it. Otherwise if vmspace_destroyed is still set we
504 * raced another thread and that thread is responsible for
507 if (imgp->vmspace_destroyed & 2)
508 p->p_flag &= ~P_INEXEC;
509 if (imgp->vmspace_destroyed) {
511 * Sorry, no more process anymore. exit gracefully.
512 * However we can't die right here, because our
513 * caller might have to clean up, so indicate a
514 * lethal error by returning -1.
523 * execve() system call.
526 sys_execve(struct execve_args *uap)
528 struct nlookupdata nd;
529 struct image_args args;
532 error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
534 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
535 uap->argv, uap->envv);
538 error = kern_execve(&nd, &args);
540 exec_free_args(&args);
543 /* We hit a lethal error condition. Let's die now. */
544 exit1(W_EXITCODE(0, SIGABRT));
549 * The syscall result is returned in registers to the new program.
550 * Linux will register %edx as an atexit function and we must be
551 * sure to set it to 0. XXX
554 uap->sysmsg_result64 = 0;
560 exec_map_first_page(struct image_params *imgp)
564 vm_page_t ma[VM_INITIAL_PAGEIN];
569 exec_unmap_first_page(imgp);
572 * The file has to be mappable.
574 if ((object = imgp->vp->v_object) == NULL)
578 * We shouldn't need protection for vm_page_grab() but we certainly
579 * need it for the lookup loop below (lookup/busy race), since
580 * an interrupt can unbusy and free the page before our busy check.
583 m = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
585 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
587 initial_pagein = VM_INITIAL_PAGEIN;
588 if (initial_pagein > object->size)
589 initial_pagein = object->size;
590 for (i = 1; i < initial_pagein; i++) {
591 if ((m = vm_page_lookup(object, i)) != NULL) {
592 if ((m->flags & PG_BUSY) || m->busy)
598 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
607 * get_pages unbusies all the requested pages except the
608 * primary page (at index 0 in this case).
610 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
611 m = vm_page_lookup(object, 0);
613 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
615 vm_page_protect(m, VM_PROT_NONE);
623 vm_page_wakeup(m); /* unbusy the page */
626 imgp->firstpage = sf_buf_alloc(m, SFB_CPUPRIVATE);
627 imgp->image_header = (void *)sf_buf_kva(imgp->firstpage);
633 exec_unmap_first_page(struct image_params *imgp)
638 if (imgp->firstpage != NULL) {
639 m = sf_buf_page(imgp->firstpage);
640 sf_buf_free(imgp->firstpage);
641 imgp->firstpage = NULL;
642 imgp->image_header = NULL;
649 * Destroy old address space, and allocate a new stack
650 * The new stack is only SGROWSIZ large because it is grown
651 * automatically in trap.c.
653 * This is the point of no return.
656 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
658 struct vmspace *vmspace = imgp->proc->p_vmspace;
659 vm_offset_t stack_addr = USRSTACK - maxssiz;
665 * Indicate that we cannot gracefully error out any more, kill
666 * any other threads present, and set P_INEXEC to indicate that
667 * we are now messing with the process structure proper.
669 * If killalllwps() races return an error which coupled with
670 * vmspace_destroyed will cause us to exit. This is what we
671 * want since another thread is patiently waiting for us to exit
675 imgp->vmspace_destroyed = 1;
677 if (curthread->td_proc->p_nthreads > 1) {
678 error = killalllwps(1);
682 imgp->vmspace_destroyed |= 2; /* we are responsible for P_INEXEC */
683 p->p_flag |= P_INEXEC;
686 * Prevent a pending AIO from modifying the new address space.
688 aio_proc_rundown(imgp->proc);
691 * Blow away entire process VM, if address space not shared,
692 * otherwise, create a new VM space so that other threads are
693 * not disrupted. If we are execing a resident vmspace we
694 * create a duplicate of it and remap the stack.
696 * The exitingcnt test is not strictly necessary but has been
697 * included for code sanity (to make the code more deterministic).
699 map = &vmspace->vm_map;
701 vmspace_exec(imgp->proc, vmcopy);
702 vmspace = imgp->proc->p_vmspace;
703 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
704 map = &vmspace->vm_map;
705 } else if (vmspace->vm_sysref.refcnt == 1 &&
706 vmspace->vm_exitingcnt == 0) {
708 if (vmspace->vm_upcalls)
709 upc_release(vmspace, ONLY_LWP_IN_PROC(imgp->proc));
710 pmap_remove_pages(vmspace_pmap(vmspace),
711 0, VM_MAX_USER_ADDRESS);
712 vm_map_remove(map, 0, VM_MAX_USER_ADDRESS);
714 vmspace_exec(imgp->proc, NULL);
715 vmspace = imgp->proc->p_vmspace;
716 map = &vmspace->vm_map;
719 /* Allocate a new stack */
720 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
721 VM_PROT_ALL, VM_PROT_ALL, 0);
725 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
726 * VM_STACK case, but they are still used to monitor the size of the
727 * process stack so we can check the stack rlimit.
729 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
730 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
736 * Copy out argument and environment strings from the old process
737 * address space into the temporary string buffer.
740 exec_copyin_args(struct image_args *args, char *fname,
741 enum exec_path_segflg segflg, char **argv, char **envv)
747 bzero(args, sizeof(*args));
749 args->buf = objcache_get(exec_objcache, M_WAITOK);
750 if (args->buf == NULL)
752 args->begin_argv = args->buf;
753 args->endp = args->begin_argv;
754 args->space = ARG_MAX;
756 args->fname = args->buf + ARG_MAX;
759 * Copy the file name.
761 if (segflg == PATH_SYSSPACE) {
762 error = copystr(fname, args->fname, PATH_MAX, &length);
763 } else if (segflg == PATH_USERSPACE) {
764 error = copyinstr(fname, args->fname, PATH_MAX, &length);
768 * Extract argument strings. argv may not be NULL. The argv
769 * array is terminated by a NULL entry. We special-case the
770 * situation where argv[0] is NULL by passing { filename, NULL }
771 * to the new program to guarentee that the interpreter knows what
772 * file to open in case we exec an interpreted file. Note that
773 * a NULL argv[0] terminates the argv[] array.
775 * XXX the special-casing of argv[0] is historical and needs to be
781 while ((argp = (caddr_t)(intptr_t)fuword(argv++)) != NULL) {
782 if (argp == (caddr_t)-1) {
786 error = copyinstr(argp, args->endp,
787 args->space, &length);
789 if (error == ENAMETOOLONG)
793 args->space -= length;
794 args->endp += length;
797 if (args->argc == 0 && error == 0) {
798 length = strlen(args->fname) + 1;
799 if (length > args->space) {
802 bcopy(args->fname, args->endp, length);
803 args->space -= length;
804 args->endp += length;
810 args->begin_envv = args->endp;
813 * extract environment strings. envv may be NULL.
815 if (envv && error == 0) {
816 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
817 if (envp == (caddr_t) -1) {
821 error = copyinstr(envp, args->endp, args->space,
824 if (error == ENAMETOOLONG)
828 args->space -= length;
829 args->endp += length;
837 exec_free_args(struct image_args *args)
840 objcache_put(exec_objcache, args->buf);
846 * Copy strings out to the new process address space, constructing
847 * new arg and env vector tables. Return a pointer to the base
848 * so that it can be used as the initial stack pointer.
851 exec_copyout_strings(struct image_params *imgp)
853 int argc, envc, sgap;
855 char *stringp, *destp;
856 register_t *stack_base;
857 struct ps_strings *arginfo;
861 * Calculate string base and vector table pointers.
862 * Also deal with signal trampoline code for this exec type.
864 arginfo = (struct ps_strings *)PS_STRINGS;
865 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
866 if (stackgap_random != 0)
867 sgap = ALIGN(karc4random() & (stackgap_random - 1));
870 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - sgap -
871 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
877 copyout(imgp->proc->p_sysent->sv_sigcode,
878 ((caddr_t)arginfo - szsigcode), szsigcode);
881 * If we have a valid auxargs ptr, prepare some room
884 * The '+ 2' is for the null pointers at the end of each of the
885 * arg and env vector sets, and 'AT_COUNT*2' is room for the
889 vectp = (char **)(destp - (imgp->args->argc +
890 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*));
892 vectp = (char **)(destp - (imgp->args->argc +
893 imgp->args->envc + 2) * sizeof(char*));
897 * NOTE: don't bother aligning the stack here for GCC 2.x, it will
898 * be done in crt1.o. Note that GCC 3.x aligns the stack in main.
902 * vectp also becomes our initial stack base
904 stack_base = (register_t *)vectp;
906 stringp = imgp->args->begin_argv;
907 argc = imgp->args->argc;
908 envc = imgp->args->envc;
911 * Copy out strings - arguments and environment.
913 copyout(stringp, destp, ARG_MAX - imgp->args->space);
916 * Fill in "ps_strings" struct for ps, w, etc.
918 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
919 suword(&arginfo->ps_nargvstr, argc);
922 * Fill in argument portion of vector table.
924 for (; argc > 0; --argc) {
925 suword(vectp++, (long)(intptr_t)destp);
926 while (*stringp++ != 0)
931 /* a null vector table pointer separates the argp's from the envp's */
934 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
935 suword(&arginfo->ps_nenvstr, envc);
938 * Fill in environment portion of vector table.
940 for (; envc > 0; --envc) {
941 suword(vectp++, (long)(intptr_t)destp);
942 while (*stringp++ != 0)
947 /* end of vector table is a null pointer */
954 * Check permissions of file to execute.
955 * Return 0 for success or error code on failure.
958 exec_check_permissions(struct image_params *imgp)
960 struct proc *p = imgp->proc;
961 struct vnode *vp = imgp->vp;
962 struct vattr *attr = imgp->attr;
965 /* Get file attributes */
966 error = VOP_GETATTR(vp, attr);
971 * 1) Check if file execution is disabled for the filesystem that this
973 * 2) Insure that at least one execute bit is on - otherwise root
974 * will always succeed, and we don't want to happen unless the
975 * file really is executable.
976 * 3) Insure that the file is a regular file.
978 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
979 ((attr->va_mode & 0111) == 0) ||
980 (attr->va_type != VREG)) {
985 * Zero length files can't be exec'd
987 if (attr->va_size == 0)
991 * Check for execute permission to file based on current credentials.
993 error = VOP_ACCESS(vp, VEXEC, p->p_ucred);
998 * Check number of open-for-writes on the file and deny execution
1001 if (vp->v_writecount)
1005 * Call filesystem specific open routine, which allows us to read,
1006 * write, and mmap the file. Without the VOP_OPEN we can only
1009 error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL);
1017 * Exec handler registration
1020 exec_register(const struct execsw *execsw_arg)
1022 const struct execsw **es, **xs, **newexecsw;
1023 int count = 2; /* New slot and trailing NULL */
1026 for (es = execsw; *es; es++)
1028 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1029 if (newexecsw == NULL)
1033 for (es = execsw; *es; es++)
1038 kfree(execsw, M_TEMP);
1044 exec_unregister(const struct execsw *execsw_arg)
1046 const struct execsw **es, **xs, **newexecsw;
1050 panic("unregister with no handlers left?");
1052 for (es = execsw; *es; es++) {
1053 if (*es == execsw_arg)
1058 for (es = execsw; *es; es++)
1059 if (*es != execsw_arg)
1061 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1062 if (newexecsw == NULL)
1065 for (es = execsw; *es; es++)
1066 if (*es != execsw_arg)
1070 kfree(execsw, M_TEMP);