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)
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 static int stackgap_random = 1024;
143 sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS)
146 new_val = stackgap_random;
147 error = sysctl_handle_int(oidp, &new_val, 0, req);
148 if (error != 0 || req->newptr == NULL)
150 if (new_val > 0 && ((new_val > 16 * PAGE_SIZE) || !powerof2(new_val)))
152 stackgap_random = new_val;
157 SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_INT,
158 0, 0, sysctl_kern_stackgap, "I",
159 "Max random stack gap (power of 2), static gap if negative");
162 print_execve_args(struct image_args *args)
167 cp = args->begin_argv;
168 for (ndx = 0; ndx < args->argc; ndx++) {
169 kprintf("\targv[%d]: %s\n", ndx, cp);
170 while (*cp++ != '\0');
172 for (ndx = 0; ndx < args->envc; ndx++) {
173 kprintf("\tenvv[%d]: %s\n", ndx, cp);
174 while (*cp++ != '\0');
179 * Each of the items is a pointer to a `const struct execsw', hence the
180 * double pointer here.
182 static const struct execsw **execsw;
185 * Replace current vmspace with a new binary.
186 * Returns 0 on success, > 0 on recoverable error (use as errno).
187 * Returns -1 on lethal error which demands killing of the current
191 kern_execve(struct nlookupdata *nd, struct image_args *args)
193 struct thread *td = curthread;
194 struct lwp *lp = td->td_lwp;
195 struct proc *p = td->td_proc;
197 register_t *stack_base;
202 struct image_params image_params, *imgp;
204 int (*img_first) (struct image_params *);
206 if (debug_execve_args) {
207 kprintf("%s()\n", __func__);
208 print_execve_args(args);
212 lwkt_gettoken(&p->p_token);
213 imgp = &image_params;
216 * NOTE: P_INEXEC is handled by exec_new_vmspace() now. We make
217 * no modifications to the process at all until we get there.
219 * Note that multiple threads may be trying to exec at the same
220 * time. exec_new_vmspace() handles that too.
224 * Initialize part of the common data
229 imgp->entry_addr = 0;
231 imgp->vmspace_destroyed = 0;
232 imgp->interpreted = 0;
233 imgp->interpreter_name[0] = 0;
234 imgp->auxargs = NULL;
236 imgp->firstpage = NULL;
237 imgp->ps_strings = 0;
238 imgp->execpath = imgp->freepath = NULL;
240 imgp->image_header = NULL;
245 * Translate the file name to a vnode. Unlock the cache entry to
246 * improve parallelism for programs exec'd in parallel.
248 if ((error = nlookup(nd)) != 0)
250 error = cache_vget(&nd->nl_nch, nd->nl_cred, LK_EXCLUSIVE, &imgp->vp);
251 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
252 nd->nl_flags &= ~NLC_NCPISLOCKED;
253 cache_unlock(&nd->nl_nch);
258 * Check file permissions (also 'opens' file).
259 * Include also the top level mount in the check.
261 error = exec_check_permissions(imgp, nd->nl_nch.mount);
264 goto exec_fail_dealloc;
267 error = exec_map_first_page(imgp);
270 goto exec_fail_dealloc;
272 imgp->proc->p_osrel = 0;
274 if (debug_execve_args && imgp->interpreted) {
275 kprintf(" target is interpreted -- recursive pass\n");
276 kprintf(" interpreter: %s\n", imgp->interpreter_name);
277 print_execve_args(args);
281 * If the current process has a special image activator it
282 * wants to try first, call it. For example, emulating shell
283 * scripts differently.
286 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
287 error = img_first(imgp);
290 * If the vnode has a registered vmspace, exec the vmspace
292 if (error == -1 && imgp->vp->v_resident) {
293 error = exec_resident_imgact(imgp);
297 * Loop through the list of image activators, calling each one.
298 * An activator returns -1 if there is no match, 0 on success,
299 * and an error otherwise.
301 for (i = 0; error == -1 && execsw[i]; ++i) {
302 if (execsw[i]->ex_imgact == NULL ||
303 execsw[i]->ex_imgact == img_first) {
306 error = (*execsw[i]->ex_imgact)(imgp);
312 goto exec_fail_dealloc;
316 * Special interpreter operation, cleanup and loop up to try to
317 * activate the interpreter.
319 if (imgp->interpreted) {
320 exec_unmap_first_page(imgp);
324 error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE,
332 * Do the best to calculate the full path to the image file
334 if (imgp->auxargs != NULL &&
335 ((args->fname != NULL && args->fname[0] == '/') ||
336 vn_fullpath(imgp->proc,
341 imgp->execpath = args->fname;
344 * Copy out strings (args and env) and initialize stack base
346 stack_base = exec_copyout_strings(imgp);
347 p->p_vmspace->vm_minsaddr = (char *)stack_base;
350 * If custom stack fixup routine present for this process
351 * let it do the stack setup. If we are running a resident
352 * image there is no auxinfo or other image activator context
353 * so don't try to add fixups to the stack.
355 * Else stuff argument count as first item on stack
357 if (p->p_sysent->sv_fixup && imgp->resident == 0)
358 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
360 suword(--stack_base, imgp->args->argc);
363 * For security and other reasons, the file descriptor table cannot
364 * be shared after an exec.
366 if (p->p_fd->fd_refcnt > 1) {
367 struct filedesc *tmp;
369 error = fdcopy(p, &tmp);
376 * For security and other reasons, signal handlers cannot
377 * be shared after an exec. The new proces gets a copy of the old
378 * handlers. In execsigs(), the new process will have its signals
382 if (ops->ps_refcnt > 1) {
383 nps = kmalloc(sizeof(*nps), M_SUBPROC, M_WAITOK);
384 bcopy(ops, nps, sizeof(*nps));
385 refcount_init(&nps->ps_refcnt, 1);
387 if (refcount_release(&ops->ps_refcnt)) {
388 kfree(ops, M_SUBPROC);
394 * For security and other reasons virtual kernels cannot be
395 * inherited by an exec. This also allows a virtual kernel
396 * to fork/exec unrelated applications.
404 /* close files on exec */
407 /* reset caught signals */
410 /* name this process - nameiexec(p, ndp) */
411 len = min(nd->nl_nch.ncp->nc_nlen, MAXCOMLEN);
412 bcopy(nd->nl_nch.ncp->nc_name, p->p_comm, len);
414 bcopy(p->p_comm, lp->lwp_thread->td_comm, MAXCOMLEN+1);
417 * mark as execed, wakeup the process that vforked (if any) and tell
418 * it that it now has its own resources back
420 p->p_flags |= P_EXEC;
421 if (p->p_pptr && (p->p_flags & P_PPWAIT)) {
422 p->p_flags &= ~P_PPWAIT;
423 wakeup((caddr_t)p->p_pptr);
427 * Implement image setuid/setgid.
429 * Don't honor setuid/setgid if the filesystem prohibits it or if
430 * the process is being traced.
432 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
433 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
434 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
435 (p->p_flags & P_TRACED) == 0) {
437 * Turn off syscall tracing for set-id programs, except for
438 * root. Record any set-id flags first to make sure that
439 * we do not regain any tracing during a possible block.
442 if (p->p_tracenode && ktrace_suid == 0 &&
443 priv_check(td, PRIV_ROOT) != 0) {
444 ktrdestroy(&p->p_tracenode);
447 /* Close any file descriptors 0..2 that reference procfs */
449 /* Make sure file descriptors 0..2 are in use. */
450 error = fdcheckstd(lp);
452 goto exec_fail_dealloc;
454 * Set the new credentials.
457 if (attr.va_mode & VSUID)
458 change_euid(attr.va_uid);
459 if (attr.va_mode & VSGID)
460 p->p_ucred->cr_gid = attr.va_gid;
463 * Clear local varsym variables
465 varsymset_clean(&p->p_varsymset);
467 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
468 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
469 p->p_flags &= ~P_SUGID;
473 * Implement correct POSIX saved-id behavior.
475 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
476 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
478 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
479 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
483 * Store the vp for use in procfs. Be sure to keep p_textvp
484 * consistent if we block during the switch-over.
487 vref(imgp->vp); /* ref new vp */
488 p->p_textvp = imgp->vp;
489 if (ovp) /* release old vp */
492 /* Release old namecache handle to text file */
493 if (p->p_textnch.ncp)
494 cache_drop(&p->p_textnch);
496 if (nd->nl_nch.mount)
497 cache_copy(&nd->nl_nch, &p->p_textnch);
500 * Notify others that we exec'd, and clear the P_INEXEC flag
501 * as we're now a bona fide freshly-execed process.
503 KNOTE(&p->p_klist, NOTE_EXEC);
504 p->p_flags &= ~P_INEXEC;
509 * If tracing the process, trap to debugger so breakpoints
510 * can be set before the program executes.
512 STOPEVENT(p, S_EXEC, 0);
514 if (p->p_flags & P_TRACED)
517 /* clear "fork but no exec" flag, as we _are_ execing */
518 p->p_acflag &= ~AFORK;
520 /* Set values passed into the program in registers. */
521 exec_setregs(imgp->entry_addr, (u_long)(uintptr_t)stack_base,
524 /* Set the access time on the vnode */
525 vn_mark_atime(imgp->vp, td);
528 * Free any previous argument cache
532 if (pa && refcount_release(&pa->ar_ref)) {
538 * Cache arguments if they fit inside our allowance
540 i = imgp->args->begin_envv - imgp->args->begin_argv;
541 if (sizeof(struct pargs) + i <= ps_arg_cache_limit) {
542 pa = kmalloc(sizeof(struct pargs) + i, M_PARGS, M_WAITOK);
543 refcount_init(&pa->ar_ref, 1);
545 bcopy(imgp->args->begin_argv, pa->ar_args, i);
546 KKASSERT(p->p_args == NULL);
553 * free various allocated resources
556 exec_unmap_first_page(imgp);
564 kfree(imgp->freepath, M_TEMP);
567 ++mycpu->gd_cnt.v_exec;
568 lwkt_reltoken(&p->p_token);
574 * we're done here, clear P_INEXEC if we were the ones that
575 * set it. Otherwise if vmspace_destroyed is still set we
576 * raced another thread and that thread is responsible for
579 if (imgp->vmspace_destroyed & 2) {
580 p->p_flags &= ~P_INEXEC;
584 lwkt_reltoken(&p->p_token);
585 if (imgp->vmspace_destroyed) {
587 * Sorry, no more process anymore. exit gracefully.
588 * However we can't die right here, because our
589 * caller might have to clean up, so indicate a
590 * lethal error by returning -1.
599 * execve() system call.
602 sys_execve(struct execve_args *uap)
604 struct nlookupdata nd;
605 struct image_args args;
608 bzero(&args, sizeof(args));
610 error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
612 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
613 uap->argv, uap->envv);
616 error = kern_execve(&nd, &args);
618 exec_free_args(&args);
621 /* We hit a lethal error condition. Let's die now. */
622 exit1(W_EXITCODE(0, SIGABRT));
627 * The syscall result is returned in registers to the new program.
628 * Linux will register %edx as an atexit function and we must be
629 * sure to set it to 0. XXX
632 uap->sysmsg_result64 = 0;
638 exec_map_page(struct image_params *imgp, vm_pindex_t pageno,
639 struct lwbuf **plwb, const char **pdata)
647 * The file has to be mappable.
649 if ((object = imgp->vp->v_object) == NULL)
652 if (pageno >= object->size)
655 vm_object_hold(object);
656 m = vm_page_grab(object, pageno, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
657 while ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
661 * get_pages unbusies all the requested pages except the
662 * primary page (at index 0 in this case). The primary
663 * page may have been wired during the pagein (e.g. by
664 * the buffer cache) so vnode_pager_freepage() must be
665 * used to properly release it.
667 rv = vm_pager_get_page(object, &ma, 1);
668 m = vm_page_lookup(object, pageno);
670 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
672 vm_page_protect(m, VM_PROT_NONE);
673 vnode_pager_freepage(m);
675 vm_object_drop(object);
680 vm_page_wakeup(m); /* unbusy the page */
681 vm_object_drop(object);
683 *plwb = lwbuf_alloc(m, *plwb);
684 *pdata = (void *)lwbuf_kva(*plwb);
690 * Map the first page of an executable image.
692 * NOTE: If the mapping fails we have to NULL-out firstpage which may
693 * still be pointing to our supplied lwp structure.
696 exec_map_first_page(struct image_params *imgp)
701 exec_unmap_first_page(imgp);
703 imgp->firstpage = &imgp->firstpage_cache;
704 err = exec_map_page(imgp, 0, &imgp->firstpage, &imgp->image_header);
707 imgp->firstpage = NULL;
715 exec_unmap_page(struct lwbuf *lwb)
729 exec_unmap_first_page(struct image_params *imgp)
731 exec_unmap_page(imgp->firstpage);
732 imgp->firstpage = NULL;
733 imgp->image_header = NULL;
737 * Destroy old address space, and allocate a new stack
738 * The new stack is only SGROWSIZ large because it is grown
739 * automatically in trap.c.
741 * This is the point of no return.
744 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
746 struct vmspace *vmspace = imgp->proc->p_vmspace;
747 vm_offset_t stack_addr = USRSTACK - maxssiz;
753 * Indicate that we cannot gracefully error out any more, kill
754 * any other threads present, and set P_INEXEC to indicate that
755 * we are now messing with the process structure proper.
757 * If killalllwps() races return an error which coupled with
758 * vmspace_destroyed will cause us to exit. This is what we
759 * want since another thread is patiently waiting for us to exit
763 imgp->vmspace_destroyed = 1;
765 if (curthread->td_proc->p_nthreads > 1) {
766 error = killalllwps(1);
770 imgp->vmspace_destroyed |= 2; /* we are responsible for P_INEXEC */
771 p->p_flags |= P_INEXEC;
774 * Tell procfs to release its hold on the process. It
775 * will return EAGAIN.
781 * After setting P_INEXEC wait for any remaining references to
782 * the process (p) to go away.
784 * In particular, a vfork/exec sequence will replace p->p_vmspace
785 * and we must interlock anyone trying to access the space (aka
786 * procfs or sys_process.c calling procfs_domem()).
788 * If P_PPWAIT is set the parent vfork()'d and has a PHOLD() on us.
790 PSTALL(p, "exec1", ((p->p_flags & P_PPWAIT) ? 1 : 0));
793 * Blow away entire process VM, if address space not shared,
794 * otherwise, create a new VM space so that other threads are
795 * not disrupted. If we are execing a resident vmspace we
796 * create a duplicate of it and remap the stack.
798 map = &vmspace->vm_map;
800 vmspace_exec(imgp->proc, vmcopy);
801 vmspace = imgp->proc->p_vmspace;
802 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
803 map = &vmspace->vm_map;
804 } else if (vmspace->vm_sysref.refcnt == 1) {
806 pmap_remove_pages(vmspace_pmap(vmspace),
807 0, VM_MAX_USER_ADDRESS);
808 vm_map_remove(map, 0, VM_MAX_USER_ADDRESS);
810 vmspace_exec(imgp->proc, NULL);
811 vmspace = imgp->proc->p_vmspace;
812 map = &vmspace->vm_map;
815 /* Allocate a new stack */
816 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
817 0, VM_PROT_ALL, VM_PROT_ALL, 0);
821 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
822 * VM_STACK case, but they are still used to monitor the size of the
823 * process stack so we can check the stack rlimit.
825 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
826 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
832 * Copy out argument and environment strings from the old process
833 * address space into the temporary string buffer.
836 exec_copyin_args(struct image_args *args, char *fname,
837 enum exec_path_segflg segflg, char **argv, char **envv)
843 args->buf = objcache_get(exec_objcache, M_WAITOK);
844 if (args->buf == NULL)
846 args->begin_argv = args->buf;
847 args->endp = args->begin_argv;
848 args->space = ARG_MAX;
850 args->fname = args->buf + ARG_MAX;
853 * Copy the file name.
855 if (segflg == PATH_SYSSPACE) {
856 error = copystr(fname, args->fname, PATH_MAX, &length);
857 } else if (segflg == PATH_USERSPACE) {
858 error = copyinstr(fname, args->fname, PATH_MAX, &length);
862 * Extract argument strings. argv may not be NULL. The argv
863 * array is terminated by a NULL entry. We special-case the
864 * situation where argv[0] is NULL by passing { filename, NULL }
865 * to the new program to guarentee that the interpreter knows what
866 * file to open in case we exec an interpreted file. Note that
867 * a NULL argv[0] terminates the argv[] array.
869 * XXX the special-casing of argv[0] is historical and needs to be
875 while ((argp = (caddr_t)(intptr_t)fuword(argv++)) != NULL) {
876 if (argp == (caddr_t)-1) {
880 error = copyinstr(argp, args->endp,
881 args->space, &length);
883 if (error == ENAMETOOLONG)
887 args->space -= length;
888 args->endp += length;
891 if (args->argc == 0 && error == 0) {
892 length = strlen(args->fname) + 1;
893 if (length > args->space) {
896 bcopy(args->fname, args->endp, length);
897 args->space -= length;
898 args->endp += length;
904 args->begin_envv = args->endp;
907 * extract environment strings. envv may be NULL.
909 if (envv && error == 0) {
910 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
911 if (envp == (caddr_t) -1) {
915 error = copyinstr(envp, args->endp,
916 args->space, &length);
918 if (error == ENAMETOOLONG)
922 args->space -= length;
923 args->endp += length;
931 exec_free_args(struct image_args *args)
934 objcache_put(exec_objcache, args->buf);
940 * Copy strings out to the new process address space, constructing
941 * new arg and env vector tables. Return a pointer to the base
942 * so that it can be used as the initial stack pointer.
944 * The format is, roughly:
950 * [args & env] <-- destp
955 * [ps_strings] top of user stack
959 exec_copyout_strings(struct image_params *imgp)
961 int argc, envc, sgap;
965 char *stringp, *destp;
966 register_t *stack_base;
967 struct ps_strings *arginfo;
972 * Calculate string base and vector table pointers.
973 * Also deal with signal trampoline code for this exec type.
975 if (imgp->execpath != NULL && imgp->auxargs != NULL)
976 execpath_len = strlen(imgp->execpath) + 1;
979 arginfo = (struct ps_strings *)PS_STRINGS;
980 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
982 argsenvspace = roundup((ARG_MAX - imgp->args->space), sizeof(char *));
983 gap = stackgap_random;
989 sgap = ALIGN(karc4random() & (gap - 1));
995 * Calculate destp, which points to [args & env] and above.
997 destp = (caddr_t)arginfo -
999 roundup(execpath_len, sizeof(char *)) -
1008 copyout(imgp->proc->p_sysent->sv_sigcode,
1009 ((caddr_t)arginfo - szsigcode), szsigcode);
1013 * Copy the image path for the rtld
1016 imgp->execpathp = (uintptr_t)arginfo
1018 - roundup(execpath_len, sizeof(char *));
1019 copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len);
1023 * Calculate base for argv[], envp[], and ELF_Auxargs.
1025 vectp = (char **)destp - (AT_COUNT * 2);
1026 vectp -= imgp->args->argc + imgp->args->envc + 2;
1028 stack_base = (register_t *)vectp;
1030 stringp = imgp->args->begin_argv;
1031 argc = imgp->args->argc;
1032 envc = imgp->args->envc;
1035 * Copy out strings - arguments and environment (at destp)
1037 copyout(stringp, destp, ARG_MAX - imgp->args->space);
1040 * Fill in "ps_strings" struct for ps, w, etc.
1042 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1043 suword32(&arginfo->ps_nargvstr, argc);
1046 * Fill in argument portion of vector table.
1048 for (; argc > 0; --argc) {
1049 suword(vectp++, (long)(intptr_t)destp);
1050 while (*stringp++ != 0)
1055 /* a null vector table pointer separates the argp's from the envp's */
1058 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1059 suword32(&arginfo->ps_nenvstr, envc);
1062 * Fill in environment portion of vector table.
1064 for (; envc > 0; --envc) {
1065 suword(vectp++, (long)(intptr_t)destp);
1066 while (*stringp++ != 0)
1071 /* end of vector table is a null pointer */
1074 return (stack_base);
1078 * Check permissions of file to execute.
1079 * Return 0 for success or error code on failure.
1082 exec_check_permissions(struct image_params *imgp, struct mount *topmnt)
1084 struct proc *p = imgp->proc;
1085 struct vnode *vp = imgp->vp;
1086 struct vattr *attr = imgp->attr;
1089 /* Get file attributes */
1090 error = VOP_GETATTR(vp, attr);
1095 * 1) Check if file execution is disabled for the filesystem that this
1097 * 2) Insure that at least one execute bit is on - otherwise root
1098 * will always succeed, and we don't want to happen unless the
1099 * file really is executable.
1100 * 3) Insure that the file is a regular file.
1102 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1103 ((topmnt != NULL) && (topmnt->mnt_flag & MNT_NOEXEC)) ||
1104 ((attr->va_mode & 0111) == 0) ||
1105 (attr->va_type != VREG)) {
1110 * Zero length files can't be exec'd
1112 if (attr->va_size == 0)
1116 * Check for execute permission to file based on current credentials.
1118 error = VOP_EACCESS(vp, VEXEC, p->p_ucred);
1123 * Check number of open-for-writes on the file and deny execution
1126 if (vp->v_writecount)
1130 * Call filesystem specific open routine, which allows us to read,
1131 * write, and mmap the file. Without the VOP_OPEN we can only
1134 error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL);
1142 * Exec handler registration
1145 exec_register(const struct execsw *execsw_arg)
1147 const struct execsw **es, **xs, **newexecsw;
1148 int count = 2; /* New slot and trailing NULL */
1151 for (es = execsw; *es; es++)
1153 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1156 for (es = execsw; *es; es++)
1161 kfree(execsw, M_TEMP);
1167 exec_unregister(const struct execsw *execsw_arg)
1169 const struct execsw **es, **xs, **newexecsw;
1173 panic("unregister with no handlers left?");
1175 for (es = execsw; *es; es++) {
1176 if (*es == execsw_arg)
1181 for (es = execsw; *es; es++)
1182 if (*es != execsw_arg)
1184 newexecsw = kmalloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1186 for (es = execsw; *es; es++)
1187 if (*es != execsw_arg)
1191 kfree(execsw, M_TEMP);