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>
72 #include <sys/objcache.h>
73 #include <sys/refcount.h>
74 #include <sys/thread2.h>
75 #include <vm/vm_page2.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 __read_mostly 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 __read_mostly static u_long usrstack = USRSTACK;
88 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
90 __read_mostly 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, "");
94 __read_mostly int ps_argsopen = 1;
95 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
97 __read_mostly 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 __read_mostly 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 __read_mostly static struct objcache *exec_objcache;
112 exec_objcache_init(void *arg __unused)
118 * Maximum number of concurrent execs. This can be limiting on
119 * systems with a lot of cpu cores but it also eats a significant
122 cluster_limit = (ncpus < 16) ? 16 : ncpus;
123 limsize = kmem_lim_size();
124 if (limsize > 7 * 1024)
126 if (limsize > 15 * 1024)
129 exec_objcache = objcache_create_mbacked(
130 M_EXECARGS, PATH_MAX + ARG_MAX,
134 SYSINIT(exec_objcache, SI_BOOT2_MACHDEP, SI_ORDER_ANY, exec_objcache_init, 0);
137 * stackgap_random specifies if the stackgap should have a random size added
138 * to it. It must be a power of 2. If non-zero, the stack gap will be
139 * calculated as: ALIGN(karc4random() & (stackgap_random - 1)).
141 __read_mostly static int stackgap_random = 1024;
144 sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS)
147 new_val = stackgap_random;
148 error = sysctl_handle_int(oidp, &new_val, 0, req);
149 if (error != 0 || req->newptr == NULL)
151 if (new_val > 0 && ((new_val > 16 * PAGE_SIZE) || !powerof2(new_val)))
153 stackgap_random = new_val;
158 SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_INT,
159 0, 0, sysctl_kern_stackgap, "I",
160 "Max random stack gap (power of 2), static gap if negative");
163 print_execve_args(struct image_args *args)
168 cp = args->begin_argv;
169 for (ndx = 0; ndx < args->argc; ndx++) {
170 kprintf("\targv[%d]: %s\n", ndx, cp);
171 while (*cp++ != '\0');
173 for (ndx = 0; ndx < args->envc; ndx++) {
174 kprintf("\tenvv[%d]: %s\n", ndx, cp);
175 while (*cp++ != '\0');
180 * Each of the items is a pointer to a `const struct execsw', hence the
181 * double pointer here.
183 __read_mostly static const struct execsw **execsw;
186 * Replace current vmspace with a new binary.
187 * Returns 0 on success, > 0 on recoverable error (use as errno).
188 * Returns -1 on lethal error which demands killing of the current
192 kern_execve(struct nlookupdata *nd, struct image_args *args)
194 struct thread *td = curthread;
195 struct lwp *lp = td->td_lwp;
196 struct proc *p = td->td_proc;
198 register_t *stack_base;
203 struct image_params image_params, *imgp;
205 int (*img_first) (struct image_params *);
207 if (debug_execve_args) {
208 kprintf("%s()\n", __func__);
209 print_execve_args(args);
213 lwkt_gettoken(&p->p_token);
214 imgp = &image_params;
217 * NOTE: P_INEXEC is handled by exec_new_vmspace() now. We make
218 * no modifications to the process at all until we get there.
220 * Note that multiple threads may be trying to exec at the same
221 * time. exec_new_vmspace() handles that too.
225 * Initialize part of the common data
230 imgp->entry_addr = 0;
232 imgp->vmspace_destroyed = 0;
233 imgp->interpreted = 0;
234 imgp->interpreter_name[0] = 0;
235 imgp->auxargs = NULL;
237 imgp->firstpage = NULL;
238 imgp->ps_strings = 0;
239 imgp->execpath = imgp->freepath = NULL;
241 imgp->image_header = NULL;
246 * Translate the file name to a vnode. Unlock the cache entry to
247 * improve parallelism for programs exec'd in parallel.
249 nd->nl_flags |= NLC_SHAREDLOCK;
250 if ((error = nlookup(nd)) != 0)
252 error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_SHARED, &imgp->vp);
253 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
254 nd->nl_flags &= ~NLC_NCPISLOCKED;
255 cache_unlock(&nd->nl_nch);
260 * Check file permissions (also 'opens' file).
261 * Include also the top level mount in the check.
263 error = exec_check_permissions(imgp, nd->nl_nch.mount);
266 goto exec_fail_dealloc;
269 error = exec_map_first_page(imgp);
272 goto exec_fail_dealloc;
274 imgp->proc->p_osrel = 0;
276 if (debug_execve_args && imgp->interpreted) {
277 kprintf(" target is interpreted -- recursive pass\n");
278 kprintf(" interpreter: %s\n", imgp->interpreter_name);
279 print_execve_args(args);
283 * If the current process has a special image activator it
284 * wants to try first, call it. For example, emulating shell
285 * scripts differently.
288 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
289 error = img_first(imgp);
292 * If the vnode has a registered vmspace, exec the vmspace
294 if (error == -1 && imgp->vp->v_resident) {
295 error = exec_resident_imgact(imgp);
299 * Loop through the list of image activators, calling each one.
300 * An activator returns -1 if there is no match, 0 on success,
301 * and an error otherwise.
303 for (i = 0; error == -1 && execsw[i]; ++i) {
304 if (execsw[i]->ex_imgact == NULL ||
305 execsw[i]->ex_imgact == img_first) {
308 error = (*execsw[i]->ex_imgact)(imgp);
314 goto exec_fail_dealloc;
318 * Special interpreter operation, cleanup and loop up to try to
319 * activate the interpreter.
321 if (imgp->interpreted) {
322 exec_unmap_first_page(imgp);
326 error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE,
334 * Do the best to calculate the full path to the image file
336 if (imgp->auxargs != NULL &&
337 ((args->fname != NULL && args->fname[0] == '/') ||
338 vn_fullpath(imgp->proc,
343 imgp->execpath = args->fname;
346 * Copy out strings (args and env) and initialize stack base
348 stack_base = exec_copyout_strings(imgp);
349 p->p_vmspace->vm_minsaddr = (char *)stack_base;
352 * If custom stack fixup routine present for this process
353 * let it do the stack setup. If we are running a resident
354 * image there is no auxinfo or other image activator context
355 * so don't try to add fixups to the stack.
357 * Else stuff argument count as first item on stack
359 if (p->p_sysent->sv_fixup && imgp->resident == 0)
360 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
362 suword64(--stack_base, imgp->args->argc);
365 * For security and other reasons, the file descriptor table cannot
366 * be shared after an exec.
368 if (p->p_fd->fd_refcnt > 1) {
369 struct filedesc *tmp;
371 error = fdcopy(p, &tmp);
378 * For security and other reasons, signal handlers cannot
379 * be shared after an exec. The new proces gets a copy of the old
380 * handlers. In execsigs(), the new process will have its signals
384 if (ops->ps_refcnt > 1) {
385 nps = kmalloc(sizeof(*nps), M_SUBPROC, M_WAITOK);
386 bcopy(ops, nps, sizeof(*nps));
387 refcount_init(&nps->ps_refcnt, 1);
389 if (refcount_release(&ops->ps_refcnt)) {
390 kfree(ops, M_SUBPROC);
396 * Clean up shared pages, the new program will allocate fresh
397 * copies as needed. This is also for security purposes and
398 * to ensure (for example) that things like sys_lpmap->blockallsigs
399 * state is properly reset on exec.
405 * For security and other reasons virtual kernels cannot be
406 * inherited by an exec. This also allows a virtual kernel
407 * to fork/exec unrelated applications.
415 /* close files on exec */
418 /* reset caught signals */
421 /* name this process - nameiexec(p, ndp) */
422 len = min(nd->nl_nch.ncp->nc_nlen, MAXCOMLEN);
423 bcopy(nd->nl_nch.ncp->nc_name, p->p_comm, len);
425 bcopy(p->p_comm, lp->lwp_thread->td_comm, MAXCOMLEN+1);
428 * mark as execed, wakeup the process that vforked (if any) and tell
429 * it that it now has its own resources back
431 * We are using the P_PPWAIT as an interlock so an atomic op is
432 * necessary to synchronize with the parent's cpu.
434 p->p_flags |= P_EXEC;
435 if (p->p_pptr && (p->p_flags & P_PPWAIT)) {
436 if (p->p_pptr->p_upmap)
437 atomic_add_int(&p->p_pptr->p_upmap->invfork, -1);
438 atomic_clear_int(&p->p_flags, P_PPWAIT);
443 * Implement image setuid/setgid.
445 * Don't honor setuid/setgid if the filesystem prohibits it or if
446 * the process is being traced.
448 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
449 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
450 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
451 (p->p_flags & P_TRACED) == 0) {
453 * Turn off syscall tracing for set-id programs, except for
454 * root. Record any set-id flags first to make sure that
455 * we do not regain any tracing during a possible block.
458 if (p->p_tracenode && ktrace_suid == 0 &&
459 priv_check(td, PRIV_ROOT) != 0) {
460 ktrdestroy(&p->p_tracenode);
463 /* Close any file descriptors 0..2 that reference procfs */
465 /* Make sure file descriptors 0..2 are in use. */
466 error = fdcheckstd(lp);
468 goto exec_fail_dealloc;
470 * Set the new credentials.
473 if (attr.va_mode & VSUID)
474 change_euid(attr.va_uid);
475 if (attr.va_mode & VSGID)
476 p->p_ucred->cr_gid = attr.va_gid;
479 * Clear local varsym variables
481 varsymset_clean(&p->p_varsymset);
483 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
484 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
485 p->p_flags &= ~P_SUGID;
489 * Implement correct POSIX saved-id behavior.
491 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
492 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
494 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
495 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
499 * Store the vp for use in procfs. Be sure to keep p_textvp
500 * consistent if we block during the switch-over.
503 vref(imgp->vp); /* ref new vp */
504 p->p_textvp = imgp->vp;
505 if (ovp) /* release old vp */
508 /* Release old namecache handle to text file */
509 if (p->p_textnch.ncp)
510 cache_drop(&p->p_textnch);
512 if (nd->nl_nch.mount)
513 cache_copy(&nd->nl_nch, &p->p_textnch);
516 * Notify others that we exec'd, and clear the P_INEXEC flag
517 * as we're now a bona fide freshly-execed process.
519 KNOTE(&p->p_klist, NOTE_EXEC);
520 p->p_flags &= ~P_INEXEC;
525 * If tracing the process, trap to debugger so breakpoints
526 * can be set before the program executes.
528 STOPEVENT(p, S_EXEC, 0);
530 if (p->p_flags & P_TRACED)
533 /* clear "fork but no exec" flag, as we _are_ execing */
534 p->p_acflag &= ~AFORK;
536 /* Set values passed into the program in registers. */
537 exec_setregs(imgp->entry_addr, (u_long)(uintptr_t)stack_base,
540 /* Set the access time on the vnode */
541 vn_mark_atime(imgp->vp, td);
544 * Free any previous argument cache
548 if (pa && refcount_release(&pa->ar_ref)) {
554 * Cache arguments if they fit inside our allowance
556 i = imgp->args->begin_envv - imgp->args->begin_argv;
557 if (sizeof(struct pargs) + i <= ps_arg_cache_limit) {
558 pa = kmalloc(sizeof(struct pargs) + i, M_PARGS, M_WAITOK);
559 refcount_init(&pa->ar_ref, 1);
561 bcopy(imgp->args->begin_argv, pa->ar_args, i);
562 KKASSERT(p->p_args == NULL);
569 * free various allocated resources
572 exec_unmap_first_page(imgp);
580 kfree(imgp->freepath, M_TEMP);
583 ++mycpu->gd_cnt.v_exec;
584 lwkt_reltoken(&p->p_token);
590 * we're done here, clear P_INEXEC if we were the ones that
591 * set it. Otherwise if vmspace_destroyed is still set we
592 * raced another thread and that thread is responsible for
595 if (imgp->vmspace_destroyed & 2) {
596 p->p_flags &= ~P_INEXEC;
600 lwkt_reltoken(&p->p_token);
601 if (imgp->vmspace_destroyed) {
603 * Sorry, no more process anymore. exit gracefully.
604 * However we can't die right here, because our
605 * caller might have to clean up, so indicate a
606 * lethal error by returning -1.
615 * execve() system call.
618 sys_execve(struct execve_args *uap)
620 struct nlookupdata nd;
621 struct image_args args;
624 bzero(&args, sizeof(args));
626 error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
628 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
629 uap->argv, uap->envv);
632 error = kern_execve(&nd, &args);
634 exec_free_args(&args);
637 /* We hit a lethal error condition. Let's die now. */
638 exit1(W_EXITCODE(0, SIGABRT));
643 * The syscall result is returned in registers to the new program.
644 * Linux will register %edx as an atexit function and we must be
645 * sure to set it to 0. XXX
648 uap->sysmsg_result64 = 0;
654 exec_map_page(struct image_params *imgp, vm_pindex_t pageno,
655 struct lwbuf **plwb, const char **pdata)
663 * The file has to be mappable.
665 if ((object = imgp->vp->v_object) == NULL)
668 if (pageno >= object->size)
672 * Shortcut using shared locks, improve concurrent execs.
674 vm_object_hold_shared(object);
675 m = vm_page_lookup(object, pageno);
677 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) {
679 vm_page_sleep_busy(m, FALSE, "execpg");
680 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL &&
681 m->object == object && m->pindex == pageno) {
682 vm_object_drop(object);
688 vm_object_drop(object);
693 vm_object_hold(object);
694 m = vm_page_grab(object, pageno, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
695 while ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
699 * get_pages unbusies all the requested pages except the
700 * primary page (at index 0 in this case). The primary
701 * page may have been wired during the pagein (e.g. by
702 * the buffer cache) so vnode_pager_freepage() must be
703 * used to properly release it.
705 rv = vm_pager_get_page(object, &ma, 1);
706 m = vm_page_lookup(object, pageno);
708 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
710 vm_page_protect(m, VM_PROT_NONE);
711 vnode_pager_freepage(m);
713 vm_object_drop(object);
718 vm_page_wakeup(m); /* unbusy the page */
719 vm_object_drop(object);
722 *plwb = lwbuf_alloc(m, *plwb);
723 *pdata = (void *)lwbuf_kva(*plwb);
729 * Map the first page of an executable image.
731 * NOTE: If the mapping fails we have to NULL-out firstpage which may
732 * still be pointing to our supplied lwp structure.
735 exec_map_first_page(struct image_params *imgp)
740 exec_unmap_first_page(imgp);
742 imgp->firstpage = &imgp->firstpage_cache;
743 err = exec_map_page(imgp, 0, &imgp->firstpage, &imgp->image_header);
746 imgp->firstpage = NULL;
754 exec_unmap_page(struct lwbuf *lwb)
768 exec_unmap_first_page(struct image_params *imgp)
770 exec_unmap_page(imgp->firstpage);
771 imgp->firstpage = NULL;
772 imgp->image_header = NULL;
776 * Destroy old address space, and allocate a new stack
777 * The new stack is only SGROWSIZ large because it is grown
778 * automatically in trap.c.
780 * This is the point of no return.
783 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
785 struct vmspace *vmspace = imgp->proc->p_vmspace;
786 vm_offset_t stack_addr = USRSTACK - maxssiz;
793 * Indicate that we cannot gracefully error out any more, kill
794 * any other threads present, and set P_INEXEC to indicate that
795 * we are now messing with the process structure proper.
797 * If killalllwps() races return an error which coupled with
798 * vmspace_destroyed will cause us to exit. This is what we
799 * want since another thread is patiently waiting for us to exit
802 lp = curthread->td_lwp;
804 imgp->vmspace_destroyed = 1;
806 if (curthread->td_proc->p_nthreads > 1) {
807 error = killalllwps(1);
811 imgp->vmspace_destroyed |= 2; /* we are responsible for P_INEXEC */
812 p->p_flags |= P_INEXEC;
815 * Tell procfs to release its hold on the process. It
816 * will return EAGAIN.
822 * After setting P_INEXEC wait for any remaining references to
823 * the process (p) to go away.
825 * In particular, a vfork/exec sequence will replace p->p_vmspace
826 * and we must interlock anyone trying to access the space (aka
827 * procfs or sys_process.c calling procfs_domem()).
829 * If P_PPWAIT is set the parent vfork()'d and has a PHOLD() on us.
831 PSTALL(p, "exec1", ((p->p_flags & P_PPWAIT) ? 1 : 0));
834 * Blow away entire process VM, if address space not shared,
835 * otherwise, create a new VM space so that other threads are
836 * not disrupted. If we are execing a resident vmspace we
837 * create a duplicate of it and remap the stack.
839 map = &vmspace->vm_map;
841 vmspace_exec(imgp->proc, vmcopy);
842 vmspace = imgp->proc->p_vmspace;
843 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
844 map = &vmspace->vm_map;
845 } else if (vmspace_getrefs(vmspace) == 1) {
847 pmap_remove_pages(vmspace_pmap(vmspace),
848 0, VM_MAX_USER_ADDRESS);
849 vm_map_remove(map, 0, VM_MAX_USER_ADDRESS);
851 vmspace_exec(imgp->proc, NULL);
852 vmspace = imgp->proc->p_vmspace;
853 map = &vmspace->vm_map;
857 * Really make sure lwp-specific and process-specific mappings
860 * Once we've done that, and because we are the only LWP left, with
861 * no TID-dependent mappings, we can reset the TID to 1 (the RB tree
862 * will remain consistent since it has only one entry). This way
863 * the exec'd program gets a nice deterministic tid of 1.
871 * Allocate a new stack, generally make the stack non-executable
872 * but allow the program to adjust that (the program may desire to
873 * use areas of the stack for executable code).
875 error = vm_map_stack(&vmspace->vm_map, &stack_addr, (vm_size_t)maxssiz,
877 VM_PROT_READ|VM_PROT_WRITE,
878 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE,
884 * vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
885 * VM_STACK case, but they are still used to monitor the size of the
886 * process stack so we can check the stack rlimit.
888 vmspace->vm_ssize = sgrowsiz; /* in bytes */
889 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
895 * Copy out argument and environment strings from the old process
896 * address space into the temporary string buffer.
899 exec_copyin_args(struct image_args *args, char *fname,
900 enum exec_path_segflg segflg, char **argv, char **envv)
906 args->buf = objcache_get(exec_objcache, M_WAITOK);
907 if (args->buf == NULL)
909 args->begin_argv = args->buf;
910 args->endp = args->begin_argv;
911 args->space = ARG_MAX;
913 args->fname = args->buf + ARG_MAX;
916 * Copy the file name.
918 if (segflg == PATH_SYSSPACE) {
919 error = copystr(fname, args->fname, PATH_MAX, &length);
920 } else if (segflg == PATH_USERSPACE) {
921 error = copyinstr(fname, args->fname, PATH_MAX, &length);
925 * Extract argument strings. argv may not be NULL. The argv
926 * array is terminated by a NULL entry. We special-case the
927 * situation where argv[0] is NULL by passing { filename, NULL }
928 * to the new program to guarentee that the interpreter knows what
929 * file to open in case we exec an interpreted file. Note that
930 * a NULL argv[0] terminates the argv[] array.
932 * XXX the special-casing of argv[0] is historical and needs to be
938 while ((argp = (caddr_t)(intptr_t)
939 fuword64((uintptr_t *)argv++)) != NULL) {
940 if (argp == (caddr_t)-1) {
944 error = copyinstr(argp, args->endp,
945 args->space, &length);
947 if (error == ENAMETOOLONG)
951 args->space -= length;
952 args->endp += length;
955 if (args->argc == 0 && error == 0) {
956 length = strlen(args->fname) + 1;
957 if (length > args->space) {
960 bcopy(args->fname, args->endp, length);
961 args->space -= length;
962 args->endp += length;
968 args->begin_envv = args->endp;
971 * extract environment strings. envv may be NULL.
973 if (envv && error == 0) {
974 while ((envp = (caddr_t)(intptr_t)
975 fuword64((uintptr_t *)envv++))) {
976 if (envp == (caddr_t) -1) {
980 error = copyinstr(envp, args->endp,
981 args->space, &length);
983 if (error == ENAMETOOLONG)
987 args->space -= length;
988 args->endp += length;
996 exec_free_args(struct image_args *args)
999 objcache_put(exec_objcache, args->buf);
1005 * Copy strings out to the new process address space, constructing
1006 * new arg and env vector tables. Return a pointer to the base
1007 * so that it can be used as the initial stack pointer.
1009 * The format is, roughly:
1011 * [argv[]] <-- vectp
1015 * [args & env] <-- destp
1020 * [ps_strings] RO|NX Top of user stack
1024 exec_copyout_strings(struct image_params *imgp)
1026 int argc, envc, sgap;
1030 char *stringp, *destp, *szsigbase;
1031 register_t *stack_base;
1032 struct ps_strings *arginfo;
1033 size_t execpath_len;
1037 * Calculate string base and vector table pointers.
1038 * Also deal with signal trampoline code for this exec type.
1040 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1041 execpath_len = strlen(imgp->execpath) + 1;
1044 arginfo = (struct ps_strings *)PS_STRINGS;
1045 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
1047 argsenvspace = roundup((ARG_MAX - imgp->args->space), sizeof(char *));
1048 gap = stackgap_random;
1054 sgap = ALIGN(karc4random() & (gap - 1));
1060 * Calculate destp, which points to [args & env] and above.
1062 szsigbase = (char *)(intptr_t)
1063 trunc_page64((intptr_t)arginfo - szsigcode);
1064 szsigbase -= SZSIGCODE_EXTRA_BYTES;
1066 roundup(execpath_len, sizeof(char *)) -
1075 copyout(imgp->proc->p_sysent->sv_sigcode, szsigbase, szsigcode);
1078 * Copy the image path for the rtld
1081 imgp->execpathp = (uintptr_t)szsigbase -
1082 roundup(execpath_len, sizeof(char *));
1083 copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len);
1087 * Calculate base for argv[], envp[], and ELF_Auxargs.
1089 vectp = (char **)destp - (AT_COUNT * 2);
1090 vectp -= imgp->args->argc + imgp->args->envc + 2;
1092 stack_base = (register_t *)vectp;
1094 stringp = imgp->args->begin_argv;
1095 argc = imgp->args->argc;
1096 envc = imgp->args->envc;
1099 * Copy out strings - arguments and environment (at destp)
1101 copyout(stringp, destp, ARG_MAX - imgp->args->space);
1104 * Fill in "ps_strings" struct for ps, w, etc.
1106 suword64((void *)&arginfo->ps_argvstr, (uint64_t)(intptr_t)vectp);
1107 suword32((void *)&arginfo->ps_nargvstr, argc);
1110 * Fill in argument portion of vector table.
1112 for (; argc > 0; --argc) {
1113 suword64((void *)vectp++, (uintptr_t)destp);
1114 while (*stringp++ != 0)
1119 /* a null vector table pointer separates the argp's from the envp's */
1120 suword64((void *)vectp++, 0);
1122 suword64((void *)&arginfo->ps_envstr, (uintptr_t)vectp);
1123 suword32((void *)&arginfo->ps_nenvstr, envc);
1126 * Fill in environment portion of vector table.
1128 for (; envc > 0; --envc) {
1129 suword64((void *)vectp++, (uintptr_t)destp);
1130 while (*stringp++ != 0)
1135 /* end of vector table is a null pointer */
1136 suword64((void *)vectp, 0);
1139 * Make the signal trampoline executable and read-only.
1141 vm_map_protect(&imgp->proc->p_vmspace->vm_map,
1142 (vm_offset_t)szsigbase,
1143 (vm_offset_t)szsigbase + PAGE_SIZE,
1144 VM_PROT_READ|VM_PROT_EXECUTE, FALSE);
1146 return (stack_base);
1150 * Check permissions of file to execute.
1151 * Return 0 for success or error code on failure.
1154 exec_check_permissions(struct image_params *imgp, struct mount *topmnt)
1156 struct proc *p = imgp->proc;
1157 struct vnode *vp = imgp->vp;
1158 struct vattr *attr = imgp->attr;
1161 /* Get file attributes */
1162 error = VOP_GETATTR(vp, attr);
1167 * 1) Check if file execution is disabled for the filesystem that this
1169 * 2) Insure that at least one execute bit is on - otherwise root
1170 * will always succeed, and we don't want to happen unless the
1171 * file really is executable.
1172 * 3) Insure that the file is a regular file.
1174 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1175 ((topmnt != NULL) && (topmnt->mnt_flag & MNT_NOEXEC)) ||
1176 ((attr->va_mode & 0111) == 0) ||
1177 (attr->va_type != VREG)) {
1182 * Zero length files can't be exec'd
1184 if (attr->va_size == 0)
1188 * Check for execute permission to file based on current credentials.
1190 error = VOP_EACCESS(vp, VEXEC, p->p_ucred);
1195 * Check number of open-for-writes on the file and deny execution
1198 if (vp->v_writecount)
1202 * Call filesystem specific open routine, which allows us to read,
1203 * write, and mmap the file. Without the VOP_OPEN we can only
1206 error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL);
1214 * Exec handler registration
1217 exec_register(const struct execsw *execsw_arg)
1219 const struct execsw **es, **xs, **newexecsw;
1220 int count = 2; /* New slot and trailing NULL */
1223 for (es = execsw; *es; es++)
1225 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1228 for (es = execsw; *es; es++)
1233 kfree(execsw, M_TEMP);
1239 exec_unregister(const struct execsw *execsw_arg)
1241 const struct execsw **es, **xs, **newexecsw;
1245 panic("unregister with no handlers left?");
1247 for (es = execsw; *es; es++) {
1248 if (*es == execsw_arg)
1253 for (es = execsw; *es; es++)
1254 if (*es != execsw_arg)
1256 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1258 for (es = execsw; *es; es++)
1259 if (*es != execsw_arg)
1263 kfree(execsw, M_TEMP);