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 1.27 2004/05/13 17:40:15 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/signalvar.h>
46 #include <sys/pioctl.h>
47 #include <sys/namei.h>
48 #include <sys/sfbuf.h>
49 #include <sys/sysent.h>
51 #include <sys/sysctl.h>
52 #include <sys/vnode.h>
53 #include <sys/vmmeter.h>
57 #include <vm/vm_param.h>
60 #include <vm/vm_page.h>
61 #include <vm/vm_map.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_extern.h>
64 #include <vm/vm_object.h>
65 #include <vm/vm_pager.h>
68 #include <machine/reg.h>
70 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
72 static register_t *exec_copyout_strings (struct image_params *);
74 /* XXX This should be vm_size_t. */
75 static u_long ps_strings = PS_STRINGS;
76 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
78 /* XXX This should be vm_size_t. */
79 static u_long usrstack = USRSTACK;
80 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
82 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
83 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
84 &ps_arg_cache_limit, 0, "");
87 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
89 void print_execve_args(struct image_args *args);
90 int debug_execve_args = 0;
91 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args,
95 print_execve_args(struct image_args *args)
100 cp = args->begin_argv;
101 for (ndx = 0; ndx < args->argc; ndx++) {
102 printf("\targv[%d]: %s\n", ndx, cp);
103 while (*cp++ != '\0');
105 for (ndx = 0; ndx < args->envc; ndx++) {
106 printf("\tenvv[%d]: %s\n", ndx, cp);
107 while (*cp++ != '\0');
112 * Each of the items is a pointer to a `const struct execsw', hence the
113 * double pointer here.
115 static const struct execsw **execsw;
118 kern_execve(struct nameidata *ndp, struct image_args *args)
120 struct thread *td = curthread;
121 struct proc *p = td->td_proc;
122 register_t *stack_base;
124 struct image_params image_params, *imgp;
126 int (*img_first) (struct image_params *);
128 if (debug_execve_args) {
129 printf("%s()\n", __func__);
130 print_execve_args(args);
134 imgp = &image_params;
137 * Lock the process and set the P_INEXEC flag to indicate that
138 * it should be left alone until we're done here. This is
139 * necessary to avoid race conditions - e.g. in ptrace() -
140 * that might allow a local user to illicitly obtain elevated
143 p->p_flag |= P_INEXEC;
146 * Initialize part of the common data
151 imgp->entry_addr = 0;
153 imgp->vmspace_destroyed = 0;
154 imgp->interpreted = 0;
155 imgp->interpreter_name[0] = 0;
156 imgp->auxargs = NULL;
158 imgp->firstpage = NULL;
159 imgp->ps_strings = 0;
160 imgp->image_header = NULL;
165 * Translate the file name. namei() returns a vnode pointer
166 * in ni_vp amoung other things.
168 if ((error = namei(ndp)) != 0)
171 imgp->vp = ndp->ni_vp;
174 * Check file permissions (also 'opens' file)
176 error = exec_check_permissions(imgp);
178 VOP_UNLOCK(imgp->vp, NULL, 0, td);
179 goto exec_fail_dealloc;
182 error = exec_map_first_page(imgp);
183 VOP_UNLOCK(imgp->vp, NULL, 0, td);
185 goto exec_fail_dealloc;
187 if (debug_execve_args && imgp->interpreted) {
188 printf(" target is interpreted -- recursive pass\n");
189 printf(" interpreter: %s\n", imgp->interpreter_name);
190 print_execve_args(args);
194 * If the current process has a special image activator it
195 * wants to try first, call it. For example, emulating shell
196 * scripts differently.
199 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
200 error = img_first(imgp);
203 * If the vnode has a registered vmspace, exec the vmspace
205 if (error == -1 && imgp->vp->v_resident) {
206 error = exec_resident_imgact(imgp);
210 * Loop through the list of image activators, calling each one.
211 * An activator returns -1 if there is no match, 0 on success,
212 * and an error otherwise.
214 for (i = 0; error == -1 && execsw[i]; ++i) {
215 if (execsw[i]->ex_imgact == NULL ||
216 execsw[i]->ex_imgact == img_first) {
219 error = (*execsw[i]->ex_imgact)(imgp);
225 goto exec_fail_dealloc;
229 * Special interpreter operation, cleanup and loop up to try to
230 * activate the interpreter.
232 if (imgp->interpreted) {
233 exec_unmap_first_page(imgp);
234 /* free name buffer and old vnode */
235 NDFREE(ndp, NDF_ONLY_PNBUF);
237 /* set new name to that of the interpreter */
238 NDINIT(ndp, NAMEI_LOOKUP,
239 CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
240 UIO_SYSSPACE, imgp->interpreter_name, td);
245 * Copy out strings (args and env) and initialize stack base
247 stack_base = exec_copyout_strings(imgp);
248 p->p_vmspace->vm_minsaddr = (char *)stack_base;
251 * If custom stack fixup routine present for this process
252 * let it do the stack setup. If we are running a resident
253 * image there is no auxinfo or other image activator context
254 * so don't try to add fixups to the stack.
256 * Else stuff argument count as first item on stack
258 if (p->p_sysent->sv_fixup && imgp->resident == 0)
259 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
261 suword(--stack_base, imgp->args->argc);
264 * For security and other reasons, the file descriptor table cannot
265 * be shared after an exec.
267 if (p->p_fd->fd_refcnt > 1) {
268 struct filedesc *tmp;
276 * For security and other reasons, signal handlers cannot
277 * be shared after an exec. The new proces gets a copy of the old
278 * handlers. In execsigs(), the new process will have its signals
281 if (p->p_procsig->ps_refcnt > 1) {
282 struct procsig *newprocsig;
284 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
285 M_SUBPROC, M_WAITOK);
286 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig));
287 p->p_procsig->ps_refcnt--;
288 p->p_procsig = newprocsig;
289 p->p_procsig->ps_refcnt = 1;
290 if (p->p_sigacts == &p->p_addr->u_sigacts)
291 panic("shared procsig but private sigacts?");
293 p->p_addr->u_sigacts = *p->p_sigacts;
294 p->p_sigacts = &p->p_addr->u_sigacts;
300 /* close files on exec */
303 /* reset caught signals */
306 /* name this process - nameiexec(p, ndp) */
307 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
308 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
312 * mark as execed, wakeup the process that vforked (if any) and tell
313 * it that it now has its own resources back
316 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
317 p->p_flag &= ~P_PPWAIT;
318 wakeup((caddr_t)p->p_pptr);
322 * Implement image setuid/setgid.
324 * Don't honor setuid/setgid if the filesystem prohibits it or if
325 * the process is being traced.
327 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
328 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
329 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
330 (p->p_flag & P_TRACED) == 0) {
332 * Turn off syscall tracing for set-id programs, except for
333 * root. Record any set-id flags first to make sure that
334 * we do not regain any tracing during a possible block.
337 if (p->p_tracep && suser(td)) {
340 if ((vtmp = p->p_tracep) != NULL) {
346 /* Close any file descriptors 0..2 that reference procfs */
348 /* Make sure file descriptors 0..2 are in use. */
349 error = fdcheckstd(p);
351 goto exec_fail_dealloc;
353 * Set the new credentials.
356 if (attr.va_mode & VSUID)
357 change_euid(attr.va_uid);
358 if (attr.va_mode & VSGID)
359 p->p_ucred->cr_gid = attr.va_gid;
362 * Clear local varsym variables
364 varsymset_clean(&p->p_varsymset);
366 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
367 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
368 p->p_flag &= ~P_SUGID;
372 * Implement correct POSIX saved-id behavior.
374 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
375 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
377 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
378 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
382 * Store the vp for use in procfs
384 if (p->p_textvp) /* release old reference */
387 p->p_textvp = ndp->ni_vp;
390 * Notify others that we exec'd, and clear the P_INEXEC flag
391 * as we're now a bona fide freshly-execed process.
393 KNOTE(&p->p_klist, NOTE_EXEC);
394 p->p_flag &= ~P_INEXEC;
397 * If tracing the process, trap to debugger so breakpoints
398 * can be set before the program executes.
400 STOPEVENT(p, S_EXEC, 0);
402 if (p->p_flag & P_TRACED)
405 /* clear "fork but no exec" flag, as we _are_ execing */
406 p->p_acflag &= ~AFORK;
408 /* Set values passed into the program in registers. */
409 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
412 /* Free any previous argument cache */
413 if (p->p_args && --p->p_args->ar_ref == 0)
414 FREE(p->p_args, M_PARGS);
417 /* Cache arguments if they fit inside our allowance */
418 i = imgp->args->begin_envv - imgp->args->begin_argv;
419 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
420 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
422 p->p_args->ar_ref = 1;
423 p->p_args->ar_length = i;
424 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i);
430 * free various allocated resources
433 exec_unmap_first_page(imgp);
436 NDFREE(ndp, NDF_ONLY_PNBUF);
441 ++mycpu->gd_cnt.v_exec;
446 /* we're done here, clear P_INEXEC */
447 p->p_flag &= ~P_INEXEC;
448 if (imgp->vmspace_destroyed) {
449 /* sorry, no more process anymore. exit gracefully */
450 exit1(W_EXITCODE(0, SIGABRT));
459 * execve() system call.
462 execve(struct execve_args *uap)
464 struct thread *td = curthread;
466 struct image_args args;
469 NDINIT(&nd, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
470 UIO_USERSPACE, uap->fname, td);
472 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
473 uap->argv, uap->envv);
475 error = kern_execve(&nd, &args);
477 exec_free_args(&args);
480 * The syscall result is returned in registers to the new program.
481 * Linux will register %edx as an atexit function and we must be
482 * sure to set it to 0. XXX
485 uap->sysmsg_result64 = 0;
491 exec_map_first_page(struct image_params *imgp)
495 vm_page_t ma[VM_INITIAL_PAGEIN];
500 exec_unmap_first_page(imgp);
502 VOP_GETVOBJECT(imgp->vp, &object);
505 * We shouldn't need protection for vm_page_grab() but we certainly
506 * need it for the lookup loop below (lookup/busy race), since
507 * an interrupt can unbusy and free the page before our busy check.
510 m = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
512 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
514 initial_pagein = VM_INITIAL_PAGEIN;
515 if (initial_pagein > object->size)
516 initial_pagein = object->size;
517 for (i = 1; i < initial_pagein; i++) {
518 if ((m = vm_page_lookup(object, i)) != NULL) {
519 if ((m->flags & PG_BUSY) || m->busy)
525 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
534 * get_pages unbusies all the requested pages except the
535 * primary page (at index 0 in this case).
537 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
538 m = vm_page_lookup(object, 0);
540 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) {
542 vm_page_protect(m, VM_PROT_NONE);
550 vm_page_wakeup(m); /* unbusy the page */
553 imgp->firstpage = sf_buf_alloc(m, SFBA_QUICK);
554 imgp->image_header = (void *)sf_buf_kva(imgp->firstpage);
560 exec_unmap_first_page(imgp)
561 struct image_params *imgp;
567 if (imgp->firstpage != NULL) {
568 m = sf_buf_page(imgp->firstpage);
569 sf_buf_free(imgp->firstpage);
570 imgp->firstpage = NULL;
571 imgp->image_header = NULL;
578 * Destroy old address space, and allocate a new stack
579 * The new stack is only SGROWSIZ large because it is grown
580 * automatically in trap.c.
583 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
586 struct vmspace *vmspace = imgp->proc->p_vmspace;
587 vm_offset_t stack_addr = USRSTACK - maxssiz;
590 imgp->vmspace_destroyed = 1;
593 * Prevent a pending AIO from modifying the new address space.
595 aio_proc_rundown(imgp->proc);
598 * Blow away entire process VM, if address space not shared,
599 * otherwise, create a new VM space so that other threads are
600 * not disrupted. If we are execing a resident vmspace we
601 * create a duplicate of it and remap the stack.
603 * The exitingcnt test is not strictly necessary but has been
604 * included for code sanity (to make the code more deterministic).
606 map = &vmspace->vm_map;
608 vmspace_exec(imgp->proc, vmcopy);
609 vmspace = imgp->proc->p_vmspace;
610 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
611 map = &vmspace->vm_map;
612 } else if (vmspace->vm_refcnt == 1 && vmspace->vm_exitingcnt == 0) {
614 if (vmspace->vm_upcalls)
615 upc_release(vmspace, imgp->proc);
616 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
617 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
619 vmspace_exec(imgp->proc, NULL);
620 vmspace = imgp->proc->p_vmspace;
621 map = &vmspace->vm_map;
624 /* Allocate a new stack */
625 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
626 VM_PROT_ALL, VM_PROT_ALL, 0);
630 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
631 * VM_STACK case, but they are still used to monitor the size of the
632 * process stack so we can check the stack rlimit.
634 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
635 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
641 * Copy out argument and environment strings from the old process
642 * address space into the temporary string buffer.
645 exec_copyin_args(struct image_args *args, char *fname,
646 enum exec_path_segflg segflg, char **argv, char **envv)
652 bzero(args, sizeof(*args));
653 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
654 if (args->buf == NULL)
656 args->begin_argv = args->buf;
657 args->endp = args->begin_argv;
658 args->space = ARG_MAX;
660 args->fname = args->buf + ARG_MAX;
663 * Copy the file name.
665 if (segflg == PATH_SYSSPACE) {
666 error = copystr(fname, args->fname, PATH_MAX, &length);
667 } else if (segflg == PATH_USERSPACE) {
668 error = copyinstr(fname, args->fname, PATH_MAX, &length);
672 * extract argument strings
675 if (argv && error == 0) {
677 * The argv0 argument for execv() is allowed to be NULL,
678 * in which case we use our filename as argv[0].
679 * This guarantees that
680 * the interpreter knows what file to open in the case
681 * that we exec an interpreted file.
683 argp = (caddr_t) (intptr_t) fuword(argv);
685 length = strlen(args->fname) + 1;
686 KKASSERT(length <= args->space);
687 bcopy(args->fname, args->endp, length);
688 args->space -= length;
689 args->endp += length;
693 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
694 if (argp == (caddr_t) -1) {
698 error = copyinstr(argp, args->endp,
699 args->space, &length);
700 if (error == ENAMETOOLONG)
704 args->space -= length;
705 args->endp += length;
710 args->begin_envv = args->endp;
713 * extract environment strings
715 if (envv && error == 0) {
716 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
717 if (envp == (caddr_t) -1) {
721 error = copyinstr(envp, args->endp, args->space,
723 if (error == ENAMETOOLONG)
727 args->space -= length;
728 args->endp += length;
738 exec_free_args(struct image_args *args)
741 kmem_free_wakeup(exec_map,
742 (vm_offset_t)args->buf, PATH_MAX + ARG_MAX);
748 * Copy strings out to the new process address space, constructing
749 * new arg and env vector tables. Return a pointer to the base
750 * so that it can be used as the initial stack pointer.
753 exec_copyout_strings(struct image_params *imgp)
757 char *stringp, *destp;
758 register_t *stack_base;
759 struct ps_strings *arginfo;
763 * Calculate string base and vector table pointers.
764 * Also deal with signal trampoline code for this exec type.
766 arginfo = (struct ps_strings *)PS_STRINGS;
767 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
768 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
769 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
775 copyout(imgp->proc->p_sysent->sv_sigcode,
776 ((caddr_t)arginfo - szsigcode), szsigcode);
779 * If we have a valid auxargs ptr, prepare some room
782 * The '+ 2' is for the null pointers at the end of each of the
783 * arg and env vector sets, and 'AT_COUNT*2' is room for the
787 vectp = (char **)(destp - (imgp->args->argc +
788 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*));
790 vectp = (char **)(destp - (imgp->args->argc +
791 imgp->args->envc + 2) * sizeof(char*));
795 * NOTE: don't bother aligning the stack here for GCC 2.x, it will
796 * be done in crt1.o. Note that GCC 3.x aligns the stack in main.
800 * vectp also becomes our initial stack base
802 stack_base = (register_t *)vectp;
804 stringp = imgp->args->begin_argv;
805 argc = imgp->args->argc;
806 envc = imgp->args->envc;
809 * Copy out strings - arguments and environment.
811 copyout(stringp, destp, ARG_MAX - imgp->args->space);
814 * Fill in "ps_strings" struct for ps, w, etc.
816 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
817 suword(&arginfo->ps_nargvstr, argc);
820 * Fill in argument portion of vector table.
822 for (; argc > 0; --argc) {
823 suword(vectp++, (long)(intptr_t)destp);
824 while (*stringp++ != 0)
829 /* a null vector table pointer separates the argp's from the envp's */
832 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
833 suword(&arginfo->ps_nenvstr, envc);
836 * Fill in environment portion of vector table.
838 for (; envc > 0; --envc) {
839 suword(vectp++, (long)(intptr_t)destp);
840 while (*stringp++ != 0)
845 /* end of vector table is a null pointer */
852 * Check permissions of file to execute.
853 * Return 0 for success or error code on failure.
856 exec_check_permissions(imgp)
857 struct image_params *imgp;
859 struct proc *p = imgp->proc;
860 struct vnode *vp = imgp->vp;
861 struct vattr *attr = imgp->attr;
862 struct thread *td = p->p_thread;
865 /* Get file attributes */
866 error = VOP_GETATTR(vp, attr, td);
871 * 1) Check if file execution is disabled for the filesystem that this
873 * 2) Insure that at least one execute bit is on - otherwise root
874 * will always succeed, and we don't want to happen unless the
875 * file really is executable.
876 * 3) Insure that the file is a regular file.
878 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
879 ((attr->va_mode & 0111) == 0) ||
880 (attr->va_type != VREG)) {
885 * Zero length files can't be exec'd
887 if (attr->va_size == 0)
891 * Check for execute permission to file based on current credentials.
893 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td);
898 * Check number of open-for-writes on the file and deny execution
901 if (vp->v_writecount)
905 * Call filesystem specific open routine (which does nothing in the
908 error = VOP_OPEN(vp, FREAD, p->p_ucred, td);
916 * Exec handler registration
919 exec_register(execsw_arg)
920 const struct execsw *execsw_arg;
922 const struct execsw **es, **xs, **newexecsw;
923 int count = 2; /* New slot and trailing NULL */
926 for (es = execsw; *es; es++)
928 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
929 if (newexecsw == NULL)
933 for (es = execsw; *es; es++)
938 free(execsw, M_TEMP);
944 exec_unregister(execsw_arg)
945 const struct execsw *execsw_arg;
947 const struct execsw **es, **xs, **newexecsw;
951 panic("unregister with no handlers left?");
953 for (es = execsw; *es; es++) {
954 if (*es == execsw_arg)
959 for (es = execsw; *es; es++)
960 if (*es != execsw_arg)
962 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
963 if (newexecsw == NULL)
966 for (es = execsw; *es; es++)
967 if (*es != execsw_arg)
971 free(execsw, M_TEMP);