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 $
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/sysproto.h>
32 #include <sys/kernel.h>
33 #include <sys/mount.h>
34 #include <sys/filedesc.h>
35 #include <sys/fcntl.h>
38 #include <sys/imgact.h>
39 #include <sys/imgact_elf.h>
40 #include <sys/kern_syscall.h>
42 #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/sysent.h>
51 #include <sys/sysctl.h>
52 #include <sys/vnode.h>
53 #include <sys/vmmeter.h>
54 #include <sys/libkern.h>
56 #include <cpu/lwbuf.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/vnode_pager.h>
68 #include <vm/vm_pager.h>
73 #include <sys/refcount.h>
74 #include <sys/thread2.h>
75 #include <sys/mplock2.h>
77 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
78 MALLOC_DEFINE(M_EXECARGS, "exec-args", "Exec arguments");
80 static register_t *exec_copyout_strings (struct image_params *);
82 /* XXX This should be vm_size_t. */
83 static u_long ps_strings = PS_STRINGS;
84 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
86 /* XXX This should be vm_size_t. */
87 static u_long usrstack = USRSTACK;
88 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
90 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
91 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
92 &ps_arg_cache_limit, 0, "");
95 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
97 static int ktrace_suid = 0;
98 SYSCTL_INT(_kern, OID_AUTO, ktrace_suid, CTLFLAG_RW, &ktrace_suid, 0, "");
100 void print_execve_args(struct image_args *args);
101 int debug_execve_args = 0;
102 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args,
106 * Exec arguments object cache
108 static struct objcache *exec_objcache;
112 exec_objcache_init(void *arg __unused)
116 cluster_limit = 16; /* up to this many objects */
117 exec_objcache = objcache_create_mbacked(
118 M_EXECARGS, PATH_MAX + ARG_MAX,
122 SYSINIT(exec_objcache, SI_BOOT2_MACHDEP, SI_ORDER_ANY, exec_objcache_init, 0);
125 * stackgap_random specifies if the stackgap should have a random size added
126 * to it. It must be a power of 2. If non-zero, the stack gap will be
127 * calculated as: ALIGN(karc4random() & (stackgap_random - 1)).
129 static int stackgap_random = 1024;
131 sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS)
134 new_val = stackgap_random;
135 error = sysctl_handle_int(oidp, &new_val, 0, req);
136 if (error != 0 || req->newptr == NULL)
138 if ((new_val < 0) || (new_val > 16 * PAGE_SIZE) || ! powerof2(new_val))
140 stackgap_random = new_val;
145 SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_UINT,
146 0, 0, sysctl_kern_stackgap, "IU", "Max random stack gap (power of 2)");
149 print_execve_args(struct image_args *args)
154 cp = args->begin_argv;
155 for (ndx = 0; ndx < args->argc; ndx++) {
156 kprintf("\targv[%d]: %s\n", ndx, cp);
157 while (*cp++ != '\0');
159 for (ndx = 0; ndx < args->envc; ndx++) {
160 kprintf("\tenvv[%d]: %s\n", ndx, cp);
161 while (*cp++ != '\0');
166 * Each of the items is a pointer to a `const struct execsw', hence the
167 * double pointer here.
169 static const struct execsw **execsw;
172 * Replace current vmspace with a new binary.
173 * Returns 0 on success, > 0 on recoverable error (use as errno).
174 * Returns -1 on lethal error which demands killing of the current
178 kern_execve(struct nlookupdata *nd, struct image_args *args)
180 struct thread *td = curthread;
181 struct lwp *lp = td->td_lwp;
182 struct proc *p = td->td_proc;
183 register_t *stack_base;
188 struct image_params image_params, *imgp;
190 int (*img_first) (struct image_params *);
192 if (debug_execve_args) {
193 kprintf("%s()\n", __func__);
194 print_execve_args(args);
198 lwkt_gettoken(&p->p_token);
199 imgp = &image_params;
202 * NOTE: P_INEXEC is handled by exec_new_vmspace() now. We make
203 * no modifications to the process at all until we get there.
205 * Note that multiple threads may be trying to exec at the same
206 * time. exec_new_vmspace() handles that too.
210 * Initialize part of the common data
215 imgp->entry_addr = 0;
217 imgp->vmspace_destroyed = 0;
218 imgp->interpreted = 0;
219 imgp->interpreter_name[0] = 0;
220 imgp->auxargs = NULL;
222 imgp->firstpage = NULL;
223 imgp->ps_strings = 0;
224 imgp->execpath = imgp->freepath = NULL;
226 imgp->image_header = NULL;
231 * Translate the file name to a vnode. Unlock the cache entry to
232 * improve parallelism for programs exec'd in parallel.
234 if ((error = nlookup(nd)) != 0)
236 error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &imgp->vp);
237 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
238 nd->nl_flags &= ~NLC_NCPISLOCKED;
239 cache_unlock(&nd->nl_nch);
244 * Check file permissions (also 'opens' file).
245 * Include also the top level mount in the check.
247 error = exec_check_permissions(imgp, nd->nl_nch.mount);
250 goto exec_fail_dealloc;
253 error = exec_map_first_page(imgp);
256 goto exec_fail_dealloc;
258 if (debug_execve_args && imgp->interpreted) {
259 kprintf(" target is interpreted -- recursive pass\n");
260 kprintf(" interpreter: %s\n", imgp->interpreter_name);
261 print_execve_args(args);
265 * If the current process has a special image activator it
266 * wants to try first, call it. For example, emulating shell
267 * scripts differently.
270 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
271 error = img_first(imgp);
274 * If the vnode has a registered vmspace, exec the vmspace
276 if (error == -1 && imgp->vp->v_resident) {
277 error = exec_resident_imgact(imgp);
281 * Loop through the list of image activators, calling each one.
282 * An activator returns -1 if there is no match, 0 on success,
283 * and an error otherwise.
285 for (i = 0; error == -1 && execsw[i]; ++i) {
286 if (execsw[i]->ex_imgact == NULL ||
287 execsw[i]->ex_imgact == img_first) {
290 error = (*execsw[i]->ex_imgact)(imgp);
296 goto exec_fail_dealloc;
300 * Special interpreter operation, cleanup and loop up to try to
301 * activate the interpreter.
303 if (imgp->interpreted) {
304 exec_unmap_first_page(imgp);
308 error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE,
316 * Do the best to calculate the full path to the image file
318 if (imgp->auxargs != NULL &&
319 ((args->fname != NULL && args->fname[0] == '/') ||
320 vn_fullpath(imgp->proc,
325 imgp->execpath = args->fname;
328 * Copy out strings (args and env) and initialize stack base
330 stack_base = exec_copyout_strings(imgp);
331 p->p_vmspace->vm_minsaddr = (char *)stack_base;
334 * If custom stack fixup routine present for this process
335 * let it do the stack setup. If we are running a resident
336 * image there is no auxinfo or other image activator context
337 * so don't try to add fixups to the stack.
339 * Else stuff argument count as first item on stack
341 if (p->p_sysent->sv_fixup && imgp->resident == 0)
342 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
344 suword(--stack_base, imgp->args->argc);
347 * For security and other reasons, the file descriptor table cannot
348 * be shared after an exec.
350 if (p->p_fd->fd_refcnt > 1) {
351 struct filedesc *tmp;
353 error = fdcopy(p, &tmp);
360 * For security and other reasons, signal handlers cannot
361 * be shared after an exec. The new proces gets a copy of the old
362 * handlers. In execsigs(), the new process will have its signals
366 if (ops->ps_refcnt > 1) {
367 nps = kmalloc(sizeof(*nps), M_SUBPROC, M_WAITOK);
368 bcopy(ops, nps, sizeof(*nps));
369 refcount_init(&nps->ps_refcnt, 1);
371 if (refcount_release(&ops->ps_refcnt)) {
372 kfree(ops, M_SUBPROC);
378 * For security and other reasons virtual kernels cannot be
379 * inherited by an exec. This also allows a virtual kernel
380 * to fork/exec unrelated applications.
388 /* close files on exec */
391 /* reset caught signals */
394 /* name this process - nameiexec(p, ndp) */
395 len = min(nd->nl_nch.ncp->nc_nlen, MAXCOMLEN);
396 bcopy(nd->nl_nch.ncp->nc_name, p->p_comm, len);
398 bcopy(p->p_comm, lp->lwp_thread->td_comm, MAXCOMLEN+1);
401 * mark as execed, wakeup the process that vforked (if any) and tell
402 * it that it now has its own resources back
405 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
406 p->p_flag &= ~P_PPWAIT;
407 wakeup((caddr_t)p->p_pptr);
411 * Implement image setuid/setgid.
413 * Don't honor setuid/setgid if the filesystem prohibits it or if
414 * the process is being traced.
416 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
417 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
418 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
419 (p->p_flag & P_TRACED) == 0) {
421 * Turn off syscall tracing for set-id programs, except for
422 * root. Record any set-id flags first to make sure that
423 * we do not regain any tracing during a possible block.
426 if (p->p_tracenode && ktrace_suid == 0 &&
427 priv_check(td, PRIV_ROOT) != 0) {
428 ktrdestroy(&p->p_tracenode);
431 /* Close any file descriptors 0..2 that reference procfs */
433 /* Make sure file descriptors 0..2 are in use. */
434 error = fdcheckstd(lp);
436 goto exec_fail_dealloc;
438 * Set the new credentials.
441 if (attr.va_mode & VSUID)
442 change_euid(attr.va_uid);
443 if (attr.va_mode & VSGID)
444 p->p_ucred->cr_gid = attr.va_gid;
447 * Clear local varsym variables
449 varsymset_clean(&p->p_varsymset);
451 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
452 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
453 p->p_flag &= ~P_SUGID;
457 * Implement correct POSIX saved-id behavior.
459 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
460 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
462 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
463 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
467 * Store the vp for use in procfs
469 if (p->p_textvp) /* release old reference */
471 p->p_textvp = imgp->vp;
474 /* Release old namecache handle to text file */
475 if (p->p_textnch.ncp)
476 cache_drop(&p->p_textnch);
478 if (nd->nl_nch.mount)
479 cache_copy(&nd->nl_nch, &p->p_textnch);
482 * Notify others that we exec'd, and clear the P_INEXEC flag
483 * as we're now a bona fide freshly-execed process.
485 KNOTE(&p->p_klist, NOTE_EXEC);
486 p->p_flag &= ~P_INEXEC;
489 * If tracing the process, trap to debugger so breakpoints
490 * can be set before the program executes.
492 STOPEVENT(p, S_EXEC, 0);
494 if (p->p_flag & P_TRACED)
497 /* clear "fork but no exec" flag, as we _are_ execing */
498 p->p_acflag &= ~AFORK;
500 /* Set values passed into the program in registers. */
501 exec_setregs(imgp->entry_addr, (u_long)(uintptr_t)stack_base,
504 /* Set the access time on the vnode */
505 vn_mark_atime(imgp->vp, td);
508 * Free any previous argument cache
512 if (pa && refcount_release(&pa->ar_ref)) {
518 * Cache arguments if they fit inside our allowance
520 i = imgp->args->begin_envv - imgp->args->begin_argv;
521 if (sizeof(struct pargs) + i <= ps_arg_cache_limit) {
522 pa = kmalloc(sizeof(struct pargs) + i, M_PARGS, M_WAITOK);
523 refcount_init(&pa->ar_ref, 1);
525 bcopy(imgp->args->begin_argv, pa->ar_args, i);
526 KKASSERT(p->p_args == NULL);
533 * free various allocated resources
536 exec_unmap_first_page(imgp);
544 ++mycpu->gd_cnt.v_exec;
545 lwkt_reltoken(&p->p_token);
550 kfree(imgp->freepath, M_TEMP);
554 * we're done here, clear P_INEXEC if we were the ones that
555 * set it. Otherwise if vmspace_destroyed is still set we
556 * raced another thread and that thread is responsible for
559 if (imgp->vmspace_destroyed & 2)
560 p->p_flag &= ~P_INEXEC;
561 lwkt_reltoken(&p->p_token);
562 if (imgp->vmspace_destroyed) {
564 * Sorry, no more process anymore. exit gracefully.
565 * However we can't die right here, because our
566 * caller might have to clean up, so indicate a
567 * lethal error by returning -1.
576 * execve() system call.
581 sys_execve(struct execve_args *uap)
583 struct nlookupdata nd;
584 struct image_args args;
587 bzero(&args, sizeof(args));
590 error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
592 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
593 uap->argv, uap->envv);
596 error = kern_execve(&nd, &args);
598 exec_free_args(&args);
601 /* We hit a lethal error condition. Let's die now. */
602 exit1(W_EXITCODE(0, SIGABRT));
608 * The syscall result is returned in registers to the new program.
609 * Linux will register %edx as an atexit function and we must be
610 * sure to set it to 0. XXX
613 uap->sysmsg_result64 = 0;
619 exec_map_page(struct image_params *imgp, vm_pindex_t pageno,
620 struct lwbuf **plwb, const char **pdata)
628 * The file has to be mappable.
630 if ((object = imgp->vp->v_object) == NULL)
633 if (pageno >= object->size)
636 m = vm_page_grab(object, pageno, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
638 lwkt_gettoken(&vm_token);
639 while ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
643 * get_pages unbusies all the requested pages except the
644 * primary page (at index 0 in this case). The primary
645 * page may have been wired during the pagein (e.g. by
646 * the buffer cache) so vnode_pager_freepage() must be
647 * used to properly release it.
649 rv = vm_pager_get_page(object, &ma, 1);
650 m = vm_page_lookup(object, pageno);
652 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
654 vm_page_protect(m, VM_PROT_NONE);
655 vnode_pager_freepage(m);
657 lwkt_reltoken(&vm_token);
661 vm_page_hold(m); /* requires vm_token to be held */
662 vm_page_wakeup(m); /* unbusy the page */
663 lwkt_reltoken(&vm_token);
665 *plwb = lwbuf_alloc(m, *plwb);
666 *pdata = (void *)lwbuf_kva(*plwb);
672 exec_map_first_page(struct image_params *imgp)
677 exec_unmap_first_page(imgp);
679 imgp->firstpage = &imgp->firstpage_cache;
680 err = exec_map_page(imgp, 0, &imgp->firstpage, &imgp->image_header);
689 exec_unmap_page(struct lwbuf *lwb)
703 exec_unmap_first_page(struct image_params *imgp)
705 exec_unmap_page(imgp->firstpage);
706 imgp->firstpage = NULL;
707 imgp->image_header = NULL;
711 * Destroy old address space, and allocate a new stack
712 * The new stack is only SGROWSIZ large because it is grown
713 * automatically in trap.c.
715 * This is the point of no return.
718 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
720 struct vmspace *vmspace = imgp->proc->p_vmspace;
721 vm_offset_t stack_addr = USRSTACK - maxssiz;
727 * Indicate that we cannot gracefully error out any more, kill
728 * any other threads present, and set P_INEXEC to indicate that
729 * we are now messing with the process structure proper.
731 * If killalllwps() races return an error which coupled with
732 * vmspace_destroyed will cause us to exit. This is what we
733 * want since another thread is patiently waiting for us to exit
737 imgp->vmspace_destroyed = 1;
739 if (curthread->td_proc->p_nthreads > 1) {
740 error = killalllwps(1);
744 imgp->vmspace_destroyed |= 2; /* we are responsible for P_INEXEC */
745 p->p_flag |= P_INEXEC;
748 * Blow away entire process VM, if address space not shared,
749 * otherwise, create a new VM space so that other threads are
750 * not disrupted. If we are execing a resident vmspace we
751 * create a duplicate of it and remap the stack.
753 * The exitingcnt test is not strictly necessary but has been
754 * included for code sanity (to make the code more deterministic).
756 map = &vmspace->vm_map;
758 vmspace_exec(imgp->proc, vmcopy);
759 vmspace = imgp->proc->p_vmspace;
760 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
761 map = &vmspace->vm_map;
762 } else if (vmspace->vm_sysref.refcnt == 1 &&
763 vmspace->vm_exitingcnt == 0) {
765 if (vmspace->vm_upcalls)
766 upc_release(vmspace, ONLY_LWP_IN_PROC(imgp->proc));
767 pmap_remove_pages(vmspace_pmap(vmspace),
768 0, VM_MAX_USER_ADDRESS);
769 vm_map_remove(map, 0, VM_MAX_USER_ADDRESS);
771 vmspace_exec(imgp->proc, NULL);
772 vmspace = imgp->proc->p_vmspace;
773 map = &vmspace->vm_map;
776 /* Allocate a new stack */
777 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
778 0, VM_PROT_ALL, VM_PROT_ALL, 0);
782 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
783 * VM_STACK case, but they are still used to monitor the size of the
784 * process stack so we can check the stack rlimit.
786 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
787 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
793 * Copy out argument and environment strings from the old process
794 * address space into the temporary string buffer.
797 exec_copyin_args(struct image_args *args, char *fname,
798 enum exec_path_segflg segflg, char **argv, char **envv)
804 args->buf = objcache_get(exec_objcache, M_WAITOK);
805 if (args->buf == NULL)
807 args->begin_argv = args->buf;
808 args->endp = args->begin_argv;
809 args->space = ARG_MAX;
811 args->fname = args->buf + ARG_MAX;
814 * Copy the file name.
816 if (segflg == PATH_SYSSPACE) {
817 error = copystr(fname, args->fname, PATH_MAX, &length);
818 } else if (segflg == PATH_USERSPACE) {
819 error = copyinstr(fname, args->fname, PATH_MAX, &length);
823 * Extract argument strings. argv may not be NULL. The argv
824 * array is terminated by a NULL entry. We special-case the
825 * situation where argv[0] is NULL by passing { filename, NULL }
826 * to the new program to guarentee that the interpreter knows what
827 * file to open in case we exec an interpreted file. Note that
828 * a NULL argv[0] terminates the argv[] array.
830 * XXX the special-casing of argv[0] is historical and needs to be
836 while ((argp = (caddr_t)(intptr_t)fuword(argv++)) != NULL) {
837 if (argp == (caddr_t)-1) {
841 error = copyinstr(argp, args->endp,
842 args->space, &length);
844 if (error == ENAMETOOLONG)
848 args->space -= length;
849 args->endp += length;
852 if (args->argc == 0 && error == 0) {
853 length = strlen(args->fname) + 1;
854 if (length > args->space) {
857 bcopy(args->fname, args->endp, length);
858 args->space -= length;
859 args->endp += length;
865 args->begin_envv = args->endp;
868 * extract environment strings. envv may be NULL.
870 if (envv && error == 0) {
871 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
872 if (envp == (caddr_t) -1) {
876 error = copyinstr(envp, args->endp, args->space,
879 if (error == ENAMETOOLONG)
883 args->space -= length;
884 args->endp += length;
892 exec_free_args(struct image_args *args)
895 objcache_put(exec_objcache, args->buf);
901 * Copy strings out to the new process address space, constructing
902 * new arg and env vector tables. Return a pointer to the base
903 * so that it can be used as the initial stack pointer.
906 exec_copyout_strings(struct image_params *imgp)
908 int argc, envc, sgap;
910 char *stringp, *destp;
911 register_t *stack_base;
912 struct ps_strings *arginfo;
917 * Calculate string base and vector table pointers.
918 * Also deal with signal trampoline code for this exec type.
920 if (imgp->execpath != NULL && imgp->auxargs != NULL)
921 execpath_len = strlen(imgp->execpath) + 1;
924 arginfo = (struct ps_strings *)PS_STRINGS;
925 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
926 if (stackgap_random != 0)
927 sgap = ALIGN(karc4random() & (stackgap_random - 1));
930 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - sgap -
931 roundup(execpath_len, sizeof(char *)) -
932 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
938 copyout(imgp->proc->p_sysent->sv_sigcode,
939 ((caddr_t)arginfo - szsigcode), szsigcode);
942 * Copy the image path for the rtld
944 if (execpath_len != 0) {
945 imgp->execpathp = (uintptr_t)arginfo
948 copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len);
952 * If we have a valid auxargs ptr, prepare some room
955 * The '+ 2' is for the null pointers at the end of each of the
956 * arg and env vector sets, and 'AT_COUNT*2' is room for the
960 vectp = (char **)(destp - (imgp->args->argc +
961 imgp->args->envc + 2 + (AT_COUNT * 2) + execpath_len) *
964 vectp = (char **)(destp - (imgp->args->argc +
965 imgp->args->envc + 2) * sizeof(char*));
969 * NOTE: don't bother aligning the stack here for GCC 2.x, it will
970 * be done in crt1.o. Note that GCC 3.x aligns the stack in main.
974 * vectp also becomes our initial stack base
976 stack_base = (register_t *)vectp;
978 stringp = imgp->args->begin_argv;
979 argc = imgp->args->argc;
980 envc = imgp->args->envc;
983 * Copy out strings - arguments and environment.
985 copyout(stringp, destp, ARG_MAX - imgp->args->space);
988 * Fill in "ps_strings" struct for ps, w, etc.
990 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
991 suword(&arginfo->ps_nargvstr, argc);
994 * Fill in argument portion of vector table.
996 for (; argc > 0; --argc) {
997 suword(vectp++, (long)(intptr_t)destp);
998 while (*stringp++ != 0)
1003 /* a null vector table pointer separates the argp's from the envp's */
1006 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1007 suword(&arginfo->ps_nenvstr, envc);
1010 * Fill in environment portion of vector table.
1012 for (; envc > 0; --envc) {
1013 suword(vectp++, (long)(intptr_t)destp);
1014 while (*stringp++ != 0)
1019 /* end of vector table is a null pointer */
1022 return (stack_base);
1026 * Check permissions of file to execute.
1027 * Return 0 for success or error code on failure.
1030 exec_check_permissions(struct image_params *imgp, struct mount *topmnt)
1032 struct proc *p = imgp->proc;
1033 struct vnode *vp = imgp->vp;
1034 struct vattr *attr = imgp->attr;
1037 /* Get file attributes */
1038 error = VOP_GETATTR(vp, attr);
1043 * 1) Check if file execution is disabled for the filesystem that this
1045 * 2) Insure that at least one execute bit is on - otherwise root
1046 * will always succeed, and we don't want to happen unless the
1047 * file really is executable.
1048 * 3) Insure that the file is a regular file.
1050 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1051 ((topmnt != NULL) && (topmnt->mnt_flag & MNT_NOEXEC)) ||
1052 ((attr->va_mode & 0111) == 0) ||
1053 (attr->va_type != VREG)) {
1058 * Zero length files can't be exec'd
1060 if (attr->va_size == 0)
1064 * Check for execute permission to file based on current credentials.
1066 error = VOP_EACCESS(vp, VEXEC, p->p_ucred);
1071 * Check number of open-for-writes on the file and deny execution
1074 if (vp->v_writecount)
1078 * Call filesystem specific open routine, which allows us to read,
1079 * write, and mmap the file. Without the VOP_OPEN we can only
1082 error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL);
1090 * Exec handler registration
1093 exec_register(const struct execsw *execsw_arg)
1095 const struct execsw **es, **xs, **newexecsw;
1096 int count = 2; /* New slot and trailing NULL */
1099 for (es = execsw; *es; es++)
1101 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1104 for (es = execsw; *es; es++)
1109 kfree(execsw, M_TEMP);
1115 exec_unregister(const struct execsw *execsw_arg)
1117 const struct execsw **es, **xs, **newexecsw;
1121 panic("unregister with no handlers left?");
1123 for (es = execsw; *es; es++) {
1124 if (*es == execsw_arg)
1129 for (es = execsw; *es; es++)
1130 if (*es != execsw_arg)
1132 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1134 for (es = execsw; *es; es++)
1135 if (*es != execsw_arg)
1139 kfree(execsw, M_TEMP);