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 1.40 2006/06/05 07:26:10 dillon 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>
70 #include <machine/reg.h>
72 #include <sys/thread2.h>
74 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
76 static register_t *exec_copyout_strings (struct image_params *);
78 /* XXX This should be vm_size_t. */
79 static u_long ps_strings = PS_STRINGS;
80 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
82 /* XXX This should be vm_size_t. */
83 static u_long usrstack = USRSTACK;
84 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
86 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
87 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
88 &ps_arg_cache_limit, 0, "");
91 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
93 void print_execve_args(struct image_args *args);
94 int debug_execve_args = 0;
95 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args,
99 * stackgap_random specifies if the stackgap should have a random size added
100 * to it. It must be a power of 2. If non-zero, the stack gap will be
101 * calculated as: ALIGN(arc4random() & (stackgap_random - 1)).
103 static int stackgap_random = 1024;
105 sysctl_kern_stackgap(SYSCTL_HANDLER_ARGS)
108 new_val = stackgap_random;
109 error = sysctl_handle_int(oidp, &new_val, 0, req);
110 if (error != 0 || req->newptr == NULL)
112 if ((new_val < 0) || (new_val > 16 * PAGE_SIZE) || ! powerof2(new_val))
114 stackgap_random = new_val;
119 SYSCTL_PROC(_kern, OID_AUTO, stackgap_random, CTLFLAG_RW|CTLTYPE_UINT,
120 0, 0, sysctl_kern_stackgap, "IU", "Max random stack gap (power of 2)");
123 print_execve_args(struct image_args *args)
128 cp = args->begin_argv;
129 for (ndx = 0; ndx < args->argc; ndx++) {
130 printf("\targv[%d]: %s\n", ndx, cp);
131 while (*cp++ != '\0');
133 for (ndx = 0; ndx < args->envc; ndx++) {
134 printf("\tenvv[%d]: %s\n", ndx, cp);
135 while (*cp++ != '\0');
140 * Each of the items is a pointer to a `const struct execsw', hence the
141 * double pointer here.
143 static const struct execsw **execsw;
146 kern_execve(struct nlookupdata *nd, struct image_args *args)
148 struct thread *td = curthread;
149 struct proc *p = td->td_proc;
150 register_t *stack_base;
152 struct image_params image_params, *imgp;
154 int (*img_first) (struct image_params *);
156 if (debug_execve_args) {
157 printf("%s()\n", __func__);
158 print_execve_args(args);
162 imgp = &image_params;
165 * Lock the process and set the P_INEXEC flag to indicate that
166 * it should be left alone until we're done here. This is
167 * necessary to avoid race conditions - e.g. in ptrace() -
168 * that might allow a local user to illicitly obtain elevated
171 p->p_flag |= P_INEXEC;
174 * Initialize part of the common data
179 imgp->entry_addr = 0;
181 imgp->vmspace_destroyed = 0;
182 imgp->interpreted = 0;
183 imgp->interpreter_name[0] = 0;
184 imgp->auxargs = NULL;
186 imgp->firstpage = NULL;
187 imgp->ps_strings = 0;
188 imgp->image_header = NULL;
193 * Translate the file name to a vnode. Unlock the cache entry to
194 * improve parallelism for programs exec'd in parallel.
196 if ((error = nlookup(nd)) != 0)
198 error = cache_vget(nd->nl_ncp, nd->nl_cred, LK_EXCLUSIVE, &imgp->vp);
199 KKASSERT(nd->nl_flags & NLC_NCPISLOCKED);
200 nd->nl_flags &= ~NLC_NCPISLOCKED;
201 cache_unlock(nd->nl_ncp);
206 * Check file permissions (also 'opens' file)
208 error = exec_check_permissions(imgp);
210 VOP_UNLOCK(imgp->vp, 0);
211 goto exec_fail_dealloc;
214 error = exec_map_first_page(imgp);
215 VOP_UNLOCK(imgp->vp, 0);
217 goto exec_fail_dealloc;
219 if (debug_execve_args && imgp->interpreted) {
220 printf(" target is interpreted -- recursive pass\n");
221 printf(" interpreter: %s\n", imgp->interpreter_name);
222 print_execve_args(args);
226 * If the current process has a special image activator it
227 * wants to try first, call it. For example, emulating shell
228 * scripts differently.
231 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
232 error = img_first(imgp);
235 * If the vnode has a registered vmspace, exec the vmspace
237 if (error == -1 && imgp->vp->v_resident) {
238 error = exec_resident_imgact(imgp);
242 * Loop through the list of image activators, calling each one.
243 * An activator returns -1 if there is no match, 0 on success,
244 * and an error otherwise.
246 for (i = 0; error == -1 && execsw[i]; ++i) {
247 if (execsw[i]->ex_imgact == NULL ||
248 execsw[i]->ex_imgact == img_first) {
251 error = (*execsw[i]->ex_imgact)(imgp);
257 goto exec_fail_dealloc;
261 * Special interpreter operation, cleanup and loop up to try to
262 * activate the interpreter.
264 if (imgp->interpreted) {
265 exec_unmap_first_page(imgp);
269 error = nlookup_init(nd, imgp->interpreter_name, UIO_SYSSPACE,
277 * Copy out strings (args and env) and initialize stack base
279 stack_base = exec_copyout_strings(imgp);
280 p->p_vmspace->vm_minsaddr = (char *)stack_base;
283 * If custom stack fixup routine present for this process
284 * let it do the stack setup. If we are running a resident
285 * image there is no auxinfo or other image activator context
286 * so don't try to add fixups to the stack.
288 * Else stuff argument count as first item on stack
290 if (p->p_sysent->sv_fixup && imgp->resident == 0)
291 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
293 suword(--stack_base, imgp->args->argc);
296 * For security and other reasons, the file descriptor table cannot
297 * be shared after an exec.
299 if (p->p_fd->fd_refcnt > 1) {
300 struct filedesc *tmp;
308 * For security and other reasons, signal handlers cannot
309 * be shared after an exec. The new proces gets a copy of the old
310 * handlers. In execsigs(), the new process will have its signals
313 if (p->p_procsig->ps_refcnt > 1) {
314 struct procsig *newprocsig;
316 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
317 M_SUBPROC, M_WAITOK);
318 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig));
319 p->p_procsig->ps_refcnt--;
320 p->p_procsig = newprocsig;
321 p->p_procsig->ps_refcnt = 1;
322 if (p->p_sigacts == &p->p_addr->u_sigacts)
323 panic("shared procsig but private sigacts?");
325 p->p_addr->u_sigacts = *p->p_sigacts;
326 p->p_sigacts = &p->p_addr->u_sigacts;
332 /* close files on exec */
335 /* reset caught signals */
338 /* name this process - nameiexec(p, ndp) */
339 len = min(nd->nl_ncp->nc_nlen, MAXCOMLEN);
340 bcopy(nd->nl_ncp->nc_name, p->p_comm, len);
342 bcopy(p->p_comm, p->p_lwp.lwp_thread->td_comm, MAXCOMLEN+1);
345 * mark as execed, wakeup the process that vforked (if any) and tell
346 * it that it now has its own resources back
349 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
350 p->p_flag &= ~P_PPWAIT;
351 wakeup((caddr_t)p->p_pptr);
355 * Implement image setuid/setgid.
357 * Don't honor setuid/setgid if the filesystem prohibits it or if
358 * the process is being traced.
360 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
361 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
362 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
363 (p->p_flag & P_TRACED) == 0) {
365 * Turn off syscall tracing for set-id programs, except for
366 * root. Record any set-id flags first to make sure that
367 * we do not regain any tracing during a possible block.
370 if (p->p_tracenode && suser(td) != 0) {
371 ktrdestroy(&p->p_tracenode);
374 /* Close any file descriptors 0..2 that reference procfs */
376 /* Make sure file descriptors 0..2 are in use. */
377 error = fdcheckstd(p);
379 goto exec_fail_dealloc;
381 * Set the new credentials.
384 if (attr.va_mode & VSUID)
385 change_euid(attr.va_uid);
386 if (attr.va_mode & VSGID)
387 p->p_ucred->cr_gid = attr.va_gid;
390 * Clear local varsym variables
392 varsymset_clean(&p->p_varsymset);
394 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
395 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
396 p->p_flag &= ~P_SUGID;
400 * Implement correct POSIX saved-id behavior.
402 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
403 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
405 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
406 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
410 * Store the vp for use in procfs
412 if (p->p_textvp) /* release old reference */
414 p->p_textvp = imgp->vp;
418 * Notify others that we exec'd, and clear the P_INEXEC flag
419 * as we're now a bona fide freshly-execed process.
421 KNOTE(&p->p_klist, NOTE_EXEC);
422 p->p_flag &= ~P_INEXEC;
425 * If tracing the process, trap to debugger so breakpoints
426 * can be set before the program executes.
428 STOPEVENT(p, S_EXEC, 0);
430 if (p->p_flag & P_TRACED)
433 /* clear "fork but no exec" flag, as we _are_ execing */
434 p->p_acflag &= ~AFORK;
436 /* Set values passed into the program in registers. */
437 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
440 /* Free any previous argument cache */
441 if (p->p_args && --p->p_args->ar_ref == 0)
442 FREE(p->p_args, M_PARGS);
445 /* Cache arguments if they fit inside our allowance */
446 i = imgp->args->begin_envv - imgp->args->begin_argv;
447 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
448 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
450 p->p_args->ar_ref = 1;
451 p->p_args->ar_length = i;
452 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i);
458 * free various allocated resources
461 exec_unmap_first_page(imgp);
469 ++mycpu->gd_cnt.v_exec;
474 /* we're done here, clear P_INEXEC */
475 p->p_flag &= ~P_INEXEC;
476 if (imgp->vmspace_destroyed) {
477 /* sorry, no more process anymore. exit gracefully */
478 exit1(W_EXITCODE(0, SIGABRT));
487 * execve() system call.
490 sys_execve(struct execve_args *uap)
492 struct nlookupdata nd;
493 struct image_args args;
496 error = nlookup_init(&nd, uap->fname, UIO_USERSPACE, NLC_FOLLOW);
498 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
499 uap->argv, uap->envv);
502 error = kern_execve(&nd, &args);
504 exec_free_args(&args);
507 * The syscall result is returned in registers to the new program.
508 * Linux will register %edx as an atexit function and we must be
509 * sure to set it to 0. XXX
512 uap->sysmsg_result64 = 0;
518 exec_map_first_page(struct image_params *imgp)
522 vm_page_t ma[VM_INITIAL_PAGEIN];
527 exec_unmap_first_page(imgp);
530 * The file has to be mappable.
532 if ((object = imgp->vp->v_object) == NULL)
536 * We shouldn't need protection for vm_page_grab() but we certainly
537 * need it for the lookup loop below (lookup/busy race), since
538 * an interrupt can unbusy and free the page before our busy check.
541 m = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
543 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
545 initial_pagein = VM_INITIAL_PAGEIN;
546 if (initial_pagein > object->size)
547 initial_pagein = object->size;
548 for (i = 1; i < initial_pagein; i++) {
549 if ((m = vm_page_lookup(object, i)) != NULL) {
550 if ((m->flags & PG_BUSY) || m->busy)
556 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
565 * get_pages unbusies all the requested pages except the
566 * primary page (at index 0 in this case).
568 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
569 m = vm_page_lookup(object, 0);
571 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
573 vm_page_protect(m, VM_PROT_NONE);
581 vm_page_wakeup(m); /* unbusy the page */
584 imgp->firstpage = sf_buf_alloc(m, SFB_CPUPRIVATE);
585 imgp->image_header = (void *)sf_buf_kva(imgp->firstpage);
591 exec_unmap_first_page(struct image_params *imgp)
596 if (imgp->firstpage != NULL) {
597 m = sf_buf_page(imgp->firstpage);
598 sf_buf_free(imgp->firstpage);
599 imgp->firstpage = NULL;
600 imgp->image_header = NULL;
607 * Destroy old address space, and allocate a new stack
608 * The new stack is only SGROWSIZ large because it is grown
609 * automatically in trap.c.
612 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
615 struct vmspace *vmspace = imgp->proc->p_vmspace;
616 vm_offset_t stack_addr = USRSTACK - maxssiz;
619 imgp->vmspace_destroyed = 1;
622 * Prevent a pending AIO from modifying the new address space.
624 aio_proc_rundown(imgp->proc);
627 * Blow away entire process VM, if address space not shared,
628 * otherwise, create a new VM space so that other threads are
629 * not disrupted. If we are execing a resident vmspace we
630 * create a duplicate of it and remap the stack.
632 * The exitingcnt test is not strictly necessary but has been
633 * included for code sanity (to make the code more deterministic).
635 map = &vmspace->vm_map;
637 vmspace_exec(imgp->proc, vmcopy);
638 vmspace = imgp->proc->p_vmspace;
639 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
640 map = &vmspace->vm_map;
641 } else if (vmspace->vm_refcnt == 1 && vmspace->vm_exitingcnt == 0) {
643 if (vmspace->vm_upcalls)
644 upc_release(vmspace, &imgp->proc->p_lwp);
645 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
646 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
648 vmspace_exec(imgp->proc, NULL);
649 vmspace = imgp->proc->p_vmspace;
650 map = &vmspace->vm_map;
653 /* Allocate a new stack */
654 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
655 VM_PROT_ALL, VM_PROT_ALL, 0);
659 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
660 * VM_STACK case, but they are still used to monitor the size of the
661 * process stack so we can check the stack rlimit.
663 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
664 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
670 * Copy out argument and environment strings from the old process
671 * address space into the temporary string buffer.
674 exec_copyin_args(struct image_args *args, char *fname,
675 enum exec_path_segflg segflg, char **argv, char **envv)
681 bzero(args, sizeof(*args));
682 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
683 if (args->buf == NULL)
685 args->begin_argv = args->buf;
686 args->endp = args->begin_argv;
687 args->space = ARG_MAX;
689 args->fname = args->buf + ARG_MAX;
692 * Copy the file name.
694 if (segflg == PATH_SYSSPACE) {
695 error = copystr(fname, args->fname, PATH_MAX, &length);
696 } else if (segflg == PATH_USERSPACE) {
697 error = copyinstr(fname, args->fname, PATH_MAX, &length);
701 * Extract argument strings. argv may not be NULL. The argv
702 * array is terminated by a NULL entry. We special-case the
703 * situation where argv[0] is NULL by passing { filename, NULL }
704 * to the new program to guarentee that the interpreter knows what
705 * file to open in case we exec an interpreted file. Note that
706 * a NULL argv[0] terminates the argv[] array.
708 * XXX the special-casing of argv[0] is historical and needs to be
714 while ((argp = (caddr_t)(intptr_t)fuword(argv++)) != NULL) {
715 if (argp == (caddr_t)-1) {
719 error = copyinstr(argp, args->endp,
720 args->space, &length);
722 if (error == ENAMETOOLONG)
726 args->space -= length;
727 args->endp += length;
730 if (args->argc == 0 && error == 0) {
731 length = strlen(args->fname) + 1;
732 if (length > args->space) {
735 bcopy(args->fname, args->endp, length);
736 args->space -= length;
737 args->endp += length;
743 args->begin_envv = args->endp;
746 * extract environment strings. envv may be NULL.
748 if (envv && error == 0) {
749 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
750 if (envp == (caddr_t) -1) {
754 error = copyinstr(envp, args->endp, args->space,
757 if (error == ENAMETOOLONG)
761 args->space -= length;
762 args->endp += length;
770 exec_free_args(struct image_args *args)
773 kmem_free_wakeup(exec_map,
774 (vm_offset_t)args->buf, PATH_MAX + ARG_MAX);
780 * Copy strings out to the new process address space, constructing
781 * new arg and env vector tables. Return a pointer to the base
782 * so that it can be used as the initial stack pointer.
785 exec_copyout_strings(struct image_params *imgp)
787 int argc, envc, sgap;
789 char *stringp, *destp;
790 register_t *stack_base;
791 struct ps_strings *arginfo;
795 * Calculate string base and vector table pointers.
796 * Also deal with signal trampoline code for this exec type.
798 arginfo = (struct ps_strings *)PS_STRINGS;
799 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
800 if (stackgap_random != 0)
801 sgap = ALIGN(arc4random() & (stackgap_random - 1));
804 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - sgap -
805 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
811 copyout(imgp->proc->p_sysent->sv_sigcode,
812 ((caddr_t)arginfo - szsigcode), szsigcode);
815 * If we have a valid auxargs ptr, prepare some room
818 * The '+ 2' is for the null pointers at the end of each of the
819 * arg and env vector sets, and 'AT_COUNT*2' is room for the
823 vectp = (char **)(destp - (imgp->args->argc +
824 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*));
826 vectp = (char **)(destp - (imgp->args->argc +
827 imgp->args->envc + 2) * sizeof(char*));
831 * NOTE: don't bother aligning the stack here for GCC 2.x, it will
832 * be done in crt1.o. Note that GCC 3.x aligns the stack in main.
836 * vectp also becomes our initial stack base
838 stack_base = (register_t *)vectp;
840 stringp = imgp->args->begin_argv;
841 argc = imgp->args->argc;
842 envc = imgp->args->envc;
845 * Copy out strings - arguments and environment.
847 copyout(stringp, destp, ARG_MAX - imgp->args->space);
850 * Fill in "ps_strings" struct for ps, w, etc.
852 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
853 suword(&arginfo->ps_nargvstr, argc);
856 * Fill in argument portion of vector table.
858 for (; argc > 0; --argc) {
859 suword(vectp++, (long)(intptr_t)destp);
860 while (*stringp++ != 0)
865 /* a null vector table pointer separates the argp's from the envp's */
868 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
869 suword(&arginfo->ps_nenvstr, envc);
872 * Fill in environment portion of vector table.
874 for (; envc > 0; --envc) {
875 suword(vectp++, (long)(intptr_t)destp);
876 while (*stringp++ != 0)
881 /* end of vector table is a null pointer */
888 * Check permissions of file to execute.
889 * Return 0 for success or error code on failure.
892 exec_check_permissions(struct image_params *imgp)
894 struct proc *p = imgp->proc;
895 struct vnode *vp = imgp->vp;
896 struct vattr *attr = imgp->attr;
899 /* Get file attributes */
900 error = VOP_GETATTR(vp, attr);
905 * 1) Check if file execution is disabled for the filesystem that this
907 * 2) Insure that at least one execute bit is on - otherwise root
908 * will always succeed, and we don't want to happen unless the
909 * file really is executable.
910 * 3) Insure that the file is a regular file.
912 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
913 ((attr->va_mode & 0111) == 0) ||
914 (attr->va_type != VREG)) {
919 * Zero length files can't be exec'd
921 if (attr->va_size == 0)
925 * Check for execute permission to file based on current credentials.
927 error = VOP_ACCESS(vp, VEXEC, p->p_ucred);
932 * Check number of open-for-writes on the file and deny execution
935 if (vp->v_writecount)
939 * Call filesystem specific open routine, which allows us to read,
940 * write, and mmap the file. Without the VOP_OPEN we can only
943 error = VOP_OPEN(vp, FREAD, p->p_ucred, NULL);
951 * Exec handler registration
954 exec_register(const struct execsw *execsw_arg)
956 const struct execsw **es, **xs, **newexecsw;
957 int count = 2; /* New slot and trailing NULL */
960 for (es = execsw; *es; es++)
962 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
963 if (newexecsw == NULL)
967 for (es = execsw; *es; es++)
972 free(execsw, M_TEMP);
978 exec_unregister(const struct execsw *execsw_arg)
980 const struct execsw **es, **xs, **newexecsw;
984 panic("unregister with no handlers left?");
986 for (es = execsw; *es; es++) {
987 if (*es == execsw_arg)
992 for (es = execsw; *es; es++)
993 if (*es != execsw_arg)
995 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
996 if (newexecsw == NULL)
999 for (es = execsw; *es; es++)
1000 if (*es != execsw_arg)
1004 free(execsw, M_TEMP);