FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_exec.c
1 /*-
2 * Copyright (c) 1993, David Greenman
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/8.0/sys/kern/kern_exec.c 197714 2009-10-02 17:58:47Z simon $");
29
30 #include "opt_hwpmc_hooks.h"
31 #include "opt_kdtrace.h"
32 #include "opt_ktrace.h"
33 #include "opt_vm.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/eventhandler.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/sysproto.h>
41 #include <sys/signalvar.h>
42 #include <sys/kernel.h>
43 #include <sys/mount.h>
44 #include <sys/filedesc.h>
45 #include <sys/fcntl.h>
46 #include <sys/acct.h>
47 #include <sys/exec.h>
48 #include <sys/imgact.h>
49 #include <sys/imgact_elf.h>
50 #include <sys/wait.h>
51 #include <sys/malloc.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/pioctl.h>
55 #include <sys/namei.h>
56 #include <sys/resourcevar.h>
57 #include <sys/sdt.h>
58 #include <sys/sf_buf.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/sysent.h>
61 #include <sys/shm.h>
62 #include <sys/sysctl.h>
63 #include <sys/vnode.h>
64 #include <sys/stat.h>
65 #ifdef KTRACE
66 #include <sys/ktrace.h>
67 #endif
68
69 #include <vm/vm.h>
70 #include <vm/vm_param.h>
71 #include <vm/pmap.h>
72 #include <vm/vm_page.h>
73 #include <vm/vm_map.h>
74 #include <vm/vm_kern.h>
75 #include <vm/vm_extern.h>
76 #include <vm/vm_object.h>
77 #include <vm/vm_pager.h>
78
79 #ifdef HWPMC_HOOKS
80 #include <sys/pmckern.h>
81 #endif
82
83 #include <machine/reg.h>
84
85 #include <security/audit/audit.h>
86 #include <security/mac/mac_framework.h>
87
88 #ifdef KDTRACE_HOOKS
89 #include <sys/dtrace_bsd.h>
90 dtrace_execexit_func_t dtrace_fasttrap_exec;
91 #endif
92
93 SDT_PROVIDER_DECLARE(proc);
94 SDT_PROBE_DEFINE(proc, kernel, , exec);
95 SDT_PROBE_ARGTYPE(proc, kernel, , exec, 0, "char *");
96 SDT_PROBE_DEFINE(proc, kernel, , exec_failure);
97 SDT_PROBE_ARGTYPE(proc, kernel, , exec_failure, 0, "int");
98 SDT_PROBE_DEFINE(proc, kernel, , exec_success);
99 SDT_PROBE_ARGTYPE(proc, kernel, , exec_success, 0, "char *");
100
101 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
102
103 static int sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS);
104 static int sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS);
105 static int sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS);
106 static int do_execve(struct thread *td, struct image_args *args,
107 struct mac *mac_p);
108 static void exec_free_args(struct image_args *);
109
110 /* XXX This should be vm_size_t. */
111 SYSCTL_PROC(_kern, KERN_PS_STRINGS, ps_strings, CTLTYPE_ULONG|CTLFLAG_RD,
112 NULL, 0, sysctl_kern_ps_strings, "LU", "");
113
114 /* XXX This should be vm_size_t. */
115 SYSCTL_PROC(_kern, KERN_USRSTACK, usrstack, CTLTYPE_ULONG|CTLFLAG_RD,
116 NULL, 0, sysctl_kern_usrstack, "LU", "");
117
118 SYSCTL_PROC(_kern, OID_AUTO, stackprot, CTLTYPE_INT|CTLFLAG_RD,
119 NULL, 0, sysctl_kern_stackprot, "I", "");
120
121 u_long ps_arg_cache_limit = PAGE_SIZE / 16;
122 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
123 &ps_arg_cache_limit, 0, "");
124
125 static int map_at_zero = 0;
126 TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
127 SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
128 "Permit processes to map an object at virtual address 0.");
129
130 static int
131 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
132 {
133 struct proc *p;
134 int error;
135
136 p = curproc;
137 #ifdef SCTL_MASK32
138 if (req->flags & SCTL_MASK32) {
139 unsigned int val;
140 val = (unsigned int)p->p_sysent->sv_psstrings;
141 error = SYSCTL_OUT(req, &val, sizeof(val));
142 } else
143 #endif
144 error = SYSCTL_OUT(req, &p->p_sysent->sv_psstrings,
145 sizeof(p->p_sysent->sv_psstrings));
146 return error;
147 }
148
149 static int
150 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
151 {
152 struct proc *p;
153 int error;
154
155 p = curproc;
156 #ifdef SCTL_MASK32
157 if (req->flags & SCTL_MASK32) {
158 unsigned int val;
159 val = (unsigned int)p->p_sysent->sv_usrstack;
160 error = SYSCTL_OUT(req, &val, sizeof(val));
161 } else
162 #endif
163 error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
164 sizeof(p->p_sysent->sv_usrstack));
165 return error;
166 }
167
168 static int
169 sysctl_kern_stackprot(SYSCTL_HANDLER_ARGS)
170 {
171 struct proc *p;
172
173 p = curproc;
174 return (SYSCTL_OUT(req, &p->p_sysent->sv_stackprot,
175 sizeof(p->p_sysent->sv_stackprot)));
176 }
177
178 /*
179 * Each of the items is a pointer to a `const struct execsw', hence the
180 * double pointer here.
181 */
182 static const struct execsw **execsw;
183
184 #ifndef _SYS_SYSPROTO_H_
185 struct execve_args {
186 char *fname;
187 char **argv;
188 char **envv;
189 };
190 #endif
191
192 int
193 execve(td, uap)
194 struct thread *td;
195 struct execve_args /* {
196 char *fname;
197 char **argv;
198 char **envv;
199 } */ *uap;
200 {
201 int error;
202 struct image_args args;
203
204 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
205 uap->argv, uap->envv);
206 if (error == 0)
207 error = kern_execve(td, &args, NULL);
208 return (error);
209 }
210
211 #ifndef _SYS_SYSPROTO_H_
212 struct fexecve_args {
213 int fd;
214 char **argv;
215 char **envv;
216 }
217 #endif
218 int
219 fexecve(struct thread *td, struct fexecve_args *uap)
220 {
221 int error;
222 struct image_args args;
223
224 error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
225 uap->argv, uap->envv);
226 if (error == 0) {
227 args.fd = uap->fd;
228 error = kern_execve(td, &args, NULL);
229 }
230 return (error);
231 }
232
233 #ifndef _SYS_SYSPROTO_H_
234 struct __mac_execve_args {
235 char *fname;
236 char **argv;
237 char **envv;
238 struct mac *mac_p;
239 };
240 #endif
241
242 int
243 __mac_execve(td, uap)
244 struct thread *td;
245 struct __mac_execve_args /* {
246 char *fname;
247 char **argv;
248 char **envv;
249 struct mac *mac_p;
250 } */ *uap;
251 {
252 #ifdef MAC
253 int error;
254 struct image_args args;
255
256 error = exec_copyin_args(&args, uap->fname, UIO_USERSPACE,
257 uap->argv, uap->envv);
258 if (error == 0)
259 error = kern_execve(td, &args, uap->mac_p);
260 return (error);
261 #else
262 return (ENOSYS);
263 #endif
264 }
265
266 /*
267 * XXX: kern_execve has the astonishing property of not always returning to
268 * the caller. If sufficiently bad things happen during the call to
269 * do_execve(), it can end up calling exit1(); as a result, callers must
270 * avoid doing anything which they might need to undo (e.g., allocating
271 * memory).
272 */
273 int
274 kern_execve(td, args, mac_p)
275 struct thread *td;
276 struct image_args *args;
277 struct mac *mac_p;
278 {
279 struct proc *p = td->td_proc;
280 int error;
281
282 AUDIT_ARG_ARGV(args->begin_argv, args->argc,
283 args->begin_envv - args->begin_argv);
284 AUDIT_ARG_ENVV(args->begin_envv, args->envc,
285 args->endp - args->begin_envv);
286 if (p->p_flag & P_HADTHREADS) {
287 PROC_LOCK(p);
288 if (thread_single(SINGLE_BOUNDARY)) {
289 PROC_UNLOCK(p);
290 exec_free_args(args);
291 return (ERESTART); /* Try again later. */
292 }
293 PROC_UNLOCK(p);
294 }
295
296 error = do_execve(td, args, mac_p);
297
298 if (p->p_flag & P_HADTHREADS) {
299 PROC_LOCK(p);
300 /*
301 * If success, we upgrade to SINGLE_EXIT state to
302 * force other threads to suicide.
303 */
304 if (error == 0)
305 thread_single(SINGLE_EXIT);
306 else
307 thread_single_end();
308 PROC_UNLOCK(p);
309 }
310
311 return (error);
312 }
313
314 /*
315 * In-kernel implementation of execve(). All arguments are assumed to be
316 * userspace pointers from the passed thread.
317 */
318 static int
319 do_execve(td, args, mac_p)
320 struct thread *td;
321 struct image_args *args;
322 struct mac *mac_p;
323 {
324 struct proc *p = td->td_proc;
325 struct nameidata nd;
326 struct ucred *newcred = NULL, *oldcred;
327 struct uidinfo *euip;
328 register_t *stack_base;
329 int error, len = 0, i;
330 struct image_params image_params, *imgp;
331 struct vattr attr;
332 int (*img_first)(struct image_params *);
333 struct pargs *oldargs = NULL, *newargs = NULL;
334 struct sigacts *oldsigacts, *newsigacts;
335 #ifdef KTRACE
336 struct vnode *tracevp = NULL;
337 struct ucred *tracecred = NULL;
338 #endif
339 struct vnode *textvp = NULL, *binvp = NULL;
340 int credential_changing;
341 int vfslocked;
342 int textset;
343 #ifdef MAC
344 struct label *interpvplabel = NULL;
345 int will_transition;
346 #endif
347 #ifdef HWPMC_HOOKS
348 struct pmckern_procexec pe;
349 #endif
350 static const char fexecv_proc_title[] = "(fexecv)";
351
352 vfslocked = 0;
353 imgp = &image_params;
354
355 /*
356 * Lock the process and set the P_INEXEC flag to indicate that
357 * it should be left alone until we're done here. This is
358 * necessary to avoid race conditions - e.g. in ptrace() -
359 * that might allow a local user to illicitly obtain elevated
360 * privileges.
361 */
362 PROC_LOCK(p);
363 KASSERT((p->p_flag & P_INEXEC) == 0,
364 ("%s(): process already has P_INEXEC flag", __func__));
365 p->p_flag |= P_INEXEC;
366 PROC_UNLOCK(p);
367
368 /*
369 * Initialize part of the common data
370 */
371 imgp->proc = p;
372 imgp->execlabel = NULL;
373 imgp->attr = &attr;
374 imgp->entry_addr = 0;
375 imgp->vmspace_destroyed = 0;
376 imgp->interpreted = 0;
377 imgp->opened = 0;
378 imgp->interpreter_name = args->buf + PATH_MAX + ARG_MAX;
379 imgp->auxargs = NULL;
380 imgp->vp = NULL;
381 imgp->object = NULL;
382 imgp->firstpage = NULL;
383 imgp->ps_strings = 0;
384 imgp->auxarg_size = 0;
385 imgp->args = args;
386 imgp->execpath = imgp->freepath = NULL;
387 imgp->execpathp = 0;
388
389 #ifdef MAC
390 error = mac_execve_enter(imgp, mac_p);
391 if (error)
392 goto exec_fail;
393 #endif
394
395 imgp->image_header = NULL;
396
397 /*
398 * Translate the file name. namei() returns a vnode pointer
399 * in ni_vp amoung other things.
400 *
401 * XXXAUDIT: It would be desirable to also audit the name of the
402 * interpreter if this is an interpreted binary.
403 */
404 if (args->fname != NULL) {
405 NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
406 | MPSAFE | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
407 }
408
409 SDT_PROBE(proc, kernel, , exec, args->fname, 0, 0, 0, 0 );
410
411 interpret:
412 if (args->fname != NULL) {
413 error = namei(&nd);
414 if (error)
415 goto exec_fail;
416
417 vfslocked = NDHASGIANT(&nd);
418 binvp = nd.ni_vp;
419 imgp->vp = binvp;
420 } else {
421 AUDIT_ARG_FD(args->fd);
422 error = fgetvp(td, args->fd, &binvp);
423 if (error)
424 goto exec_fail;
425 vfslocked = VFS_LOCK_GIANT(binvp->v_mount);
426 vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
427 AUDIT_ARG_VNODE1(binvp);
428 imgp->vp = binvp;
429 }
430
431 /*
432 * Check file permissions (also 'opens' file)
433 */
434 error = exec_check_permissions(imgp);
435 if (error)
436 goto exec_fail_dealloc;
437
438 imgp->object = imgp->vp->v_object;
439 if (imgp->object != NULL)
440 vm_object_reference(imgp->object);
441
442 /*
443 * Set VV_TEXT now so no one can write to the executable while we're
444 * activating it.
445 *
446 * Remember if this was set before and unset it in case this is not
447 * actually an executable image.
448 */
449 textset = imgp->vp->v_vflag & VV_TEXT;
450 imgp->vp->v_vflag |= VV_TEXT;
451
452 error = exec_map_first_page(imgp);
453 if (error)
454 goto exec_fail_dealloc;
455
456 imgp->proc->p_osrel = 0;
457 /*
458 * If the current process has a special image activator it
459 * wants to try first, call it. For example, emulating shell
460 * scripts differently.
461 */
462 error = -1;
463 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
464 error = img_first(imgp);
465
466 /*
467 * Loop through the list of image activators, calling each one.
468 * An activator returns -1 if there is no match, 0 on success,
469 * and an error otherwise.
470 */
471 for (i = 0; error == -1 && execsw[i]; ++i) {
472 if (execsw[i]->ex_imgact == NULL ||
473 execsw[i]->ex_imgact == img_first) {
474 continue;
475 }
476 error = (*execsw[i]->ex_imgact)(imgp);
477 }
478
479 if (error) {
480 if (error == -1) {
481 if (textset == 0)
482 imgp->vp->v_vflag &= ~VV_TEXT;
483 error = ENOEXEC;
484 }
485 goto exec_fail_dealloc;
486 }
487
488 /*
489 * Special interpreter operation, cleanup and loop up to try to
490 * activate the interpreter.
491 */
492 if (imgp->interpreted) {
493 exec_unmap_first_page(imgp);
494 /*
495 * VV_TEXT needs to be unset for scripts. There is a short
496 * period before we determine that something is a script where
497 * VV_TEXT will be set. The vnode lock is held over this
498 * entire period so nothing should illegitimately be blocked.
499 */
500 imgp->vp->v_vflag &= ~VV_TEXT;
501 /* free name buffer and old vnode */
502 if (args->fname != NULL)
503 NDFREE(&nd, NDF_ONLY_PNBUF);
504 #ifdef MAC
505 mac_execve_interpreter_enter(binvp, &interpvplabel);
506 #endif
507 if (imgp->opened) {
508 VOP_CLOSE(binvp, FREAD, td->td_ucred, td);
509 imgp->opened = 0;
510 }
511 vput(binvp);
512 vm_object_deallocate(imgp->object);
513 imgp->object = NULL;
514 VFS_UNLOCK_GIANT(vfslocked);
515 vfslocked = 0;
516 /* set new name to that of the interpreter */
517 NDINIT(&nd, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE,
518 UIO_SYSSPACE, imgp->interpreter_name, td);
519 args->fname = imgp->interpreter_name;
520 goto interpret;
521 }
522
523 /*
524 * NB: We unlock the vnode here because it is believed that none
525 * of the sv_copyout_strings/sv_fixup operations require the vnode.
526 */
527 VOP_UNLOCK(imgp->vp, 0);
528
529 /*
530 * Do the best to calculate the full path to the image file.
531 */
532 if (imgp->auxargs != NULL &&
533 ((args->fname != NULL && args->fname[0] == '/') ||
534 vn_fullpath(td, imgp->vp, &imgp->execpath, &imgp->freepath) != 0))
535 imgp->execpath = args->fname;
536
537 /*
538 * Copy out strings (args and env) and initialize stack base
539 */
540 if (p->p_sysent->sv_copyout_strings)
541 stack_base = (*p->p_sysent->sv_copyout_strings)(imgp);
542 else
543 stack_base = exec_copyout_strings(imgp);
544
545 /*
546 * If custom stack fixup routine present for this process
547 * let it do the stack setup.
548 * Else stuff argument count as first item on stack
549 */
550 if (p->p_sysent->sv_fixup != NULL)
551 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
552 else
553 suword(--stack_base, imgp->args->argc);
554
555 /*
556 * For security and other reasons, the file descriptor table cannot
557 * be shared after an exec.
558 */
559 fdunshare(p, td);
560
561 /*
562 * Malloc things before we need locks.
563 */
564 newcred = crget();
565 euip = uifind(attr.va_uid);
566 i = imgp->args->begin_envv - imgp->args->begin_argv;
567 /* Cache arguments if they fit inside our allowance */
568 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
569 newargs = pargs_alloc(i);
570 bcopy(imgp->args->begin_argv, newargs->ar_args, i);
571 }
572
573 /* close files on exec */
574 fdcloseexec(td);
575 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
576
577 /* Get a reference to the vnode prior to locking the proc */
578 VREF(binvp);
579
580 /*
581 * For security and other reasons, signal handlers cannot
582 * be shared after an exec. The new process gets a copy of the old
583 * handlers. In execsigs(), the new process will have its signals
584 * reset.
585 */
586 PROC_LOCK(p);
587 oldcred = crcopysafe(p, newcred);
588 if (sigacts_shared(p->p_sigacts)) {
589 oldsigacts = p->p_sigacts;
590 PROC_UNLOCK(p);
591 newsigacts = sigacts_alloc();
592 sigacts_copy(newsigacts, oldsigacts);
593 PROC_LOCK(p);
594 p->p_sigacts = newsigacts;
595 } else
596 oldsigacts = NULL;
597
598 /* Stop profiling */
599 stopprofclock(p);
600
601 /* reset caught signals */
602 execsigs(p);
603
604 /* name this process - nameiexec(p, ndp) */
605 if (args->fname) {
606 len = min(nd.ni_cnd.cn_namelen,MAXCOMLEN);
607 bcopy(nd.ni_cnd.cn_nameptr, p->p_comm, len);
608 } else {
609 if (vn_commname(binvp, p->p_comm, MAXCOMLEN + 1) == 0)
610 len = MAXCOMLEN;
611 else {
612 len = sizeof(fexecv_proc_title);
613 bcopy(fexecv_proc_title, p->p_comm, len);
614 }
615 }
616 p->p_comm[len] = 0;
617 bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
618
619 /*
620 * mark as execed, wakeup the process that vforked (if any) and tell
621 * it that it now has its own resources back
622 */
623 p->p_flag |= P_EXEC;
624 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
625 p->p_flag &= ~P_PPWAIT;
626 cv_broadcast(&p->p_pwait);
627 }
628
629 /*
630 * Implement image setuid/setgid.
631 *
632 * Don't honor setuid/setgid if the filesystem prohibits it or if
633 * the process is being traced.
634 *
635 * XXXMAC: For the time being, use NOSUID to also prohibit
636 * transitions on the file system.
637 */
638 credential_changing = 0;
639 credential_changing |= (attr.va_mode & S_ISUID) && oldcred->cr_uid !=
640 attr.va_uid;
641 credential_changing |= (attr.va_mode & S_ISGID) && oldcred->cr_gid !=
642 attr.va_gid;
643 #ifdef MAC
644 will_transition = mac_vnode_execve_will_transition(oldcred, imgp->vp,
645 interpvplabel, imgp);
646 credential_changing |= will_transition;
647 #endif
648
649 if (credential_changing &&
650 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
651 (p->p_flag & P_TRACED) == 0) {
652 /*
653 * Turn off syscall tracing for set-id programs, except for
654 * root. Record any set-id flags first to make sure that
655 * we do not regain any tracing during a possible block.
656 */
657 setsugid(p);
658
659 #ifdef KTRACE
660 if (p->p_tracevp != NULL &&
661 priv_check_cred(oldcred, PRIV_DEBUG_DIFFCRED, 0)) {
662 mtx_lock(&ktrace_mtx);
663 p->p_traceflag = 0;
664 tracevp = p->p_tracevp;
665 p->p_tracevp = NULL;
666 tracecred = p->p_tracecred;
667 p->p_tracecred = NULL;
668 mtx_unlock(&ktrace_mtx);
669 }
670 #endif
671 /*
672 * Close any file descriptors 0..2 that reference procfs,
673 * then make sure file descriptors 0..2 are in use.
674 *
675 * setugidsafety() may call closef() and then pfind()
676 * which may grab the process lock.
677 * fdcheckstd() may call falloc() which may block to
678 * allocate memory, so temporarily drop the process lock.
679 */
680 PROC_UNLOCK(p);
681 VOP_UNLOCK(imgp->vp, 0);
682 setugidsafety(td);
683 error = fdcheckstd(td);
684 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
685 if (error != 0)
686 goto done1;
687 PROC_LOCK(p);
688 /*
689 * Set the new credentials.
690 */
691 if (attr.va_mode & S_ISUID)
692 change_euid(newcred, euip);
693 if (attr.va_mode & S_ISGID)
694 change_egid(newcred, attr.va_gid);
695 #ifdef MAC
696 if (will_transition) {
697 mac_vnode_execve_transition(oldcred, newcred, imgp->vp,
698 interpvplabel, imgp);
699 }
700 #endif
701 /*
702 * Implement correct POSIX saved-id behavior.
703 *
704 * XXXMAC: Note that the current logic will save the
705 * uid and gid if a MAC domain transition occurs, even
706 * though maybe it shouldn't.
707 */
708 change_svuid(newcred, newcred->cr_uid);
709 change_svgid(newcred, newcred->cr_gid);
710 p->p_ucred = newcred;
711 newcred = NULL;
712 } else {
713 if (oldcred->cr_uid == oldcred->cr_ruid &&
714 oldcred->cr_gid == oldcred->cr_rgid)
715 p->p_flag &= ~P_SUGID;
716 /*
717 * Implement correct POSIX saved-id behavior.
718 *
719 * XXX: It's not clear that the existing behavior is
720 * POSIX-compliant. A number of sources indicate that the
721 * saved uid/gid should only be updated if the new ruid is
722 * not equal to the old ruid, or the new euid is not equal
723 * to the old euid and the new euid is not equal to the old
724 * ruid. The FreeBSD code always updates the saved uid/gid.
725 * Also, this code uses the new (replaced) euid and egid as
726 * the source, which may or may not be the right ones to use.
727 */
728 if (oldcred->cr_svuid != oldcred->cr_uid ||
729 oldcred->cr_svgid != oldcred->cr_gid) {
730 change_svuid(newcred, newcred->cr_uid);
731 change_svgid(newcred, newcred->cr_gid);
732 p->p_ucred = newcred;
733 newcred = NULL;
734 }
735 }
736
737 /*
738 * Store the vp for use in procfs. This vnode was referenced prior
739 * to locking the proc lock.
740 */
741 textvp = p->p_textvp;
742 p->p_textvp = binvp;
743
744 #ifdef KDTRACE_HOOKS
745 /*
746 * Tell the DTrace fasttrap provider about the exec if it
747 * has declared an interest.
748 */
749 if (dtrace_fasttrap_exec)
750 dtrace_fasttrap_exec(p);
751 #endif
752
753 /*
754 * Notify others that we exec'd, and clear the P_INEXEC flag
755 * as we're now a bona fide freshly-execed process.
756 */
757 KNOTE_LOCKED(&p->p_klist, NOTE_EXEC);
758 p->p_flag &= ~P_INEXEC;
759
760 /*
761 * If tracing the process, trap to debugger so breakpoints
762 * can be set before the program executes.
763 * Use tdsignal to deliver signal to current thread, use
764 * psignal may cause the signal to be delivered to wrong thread
765 * because that thread will exit, remember we are going to enter
766 * single thread mode.
767 */
768 if (p->p_flag & P_TRACED)
769 tdsignal(p, td, SIGTRAP, NULL);
770
771 /* clear "fork but no exec" flag, as we _are_ execing */
772 p->p_acflag &= ~AFORK;
773
774 /*
775 * Free any previous argument cache and replace it with
776 * the new argument cache, if any.
777 */
778 oldargs = p->p_args;
779 p->p_args = newargs;
780 newargs = NULL;
781
782 #ifdef HWPMC_HOOKS
783 /*
784 * Check if system-wide sampling is in effect or if the
785 * current process is using PMCs. If so, do exec() time
786 * processing. This processing needs to happen AFTER the
787 * P_INEXEC flag is cleared.
788 *
789 * The proc lock needs to be released before taking the PMC
790 * SX.
791 */
792 if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) {
793 PROC_UNLOCK(p);
794 VOP_UNLOCK(imgp->vp, 0);
795 pe.pm_credentialschanged = credential_changing;
796 pe.pm_entryaddr = imgp->entry_addr;
797
798 PMC_CALL_HOOK_X(td, PMC_FN_PROCESS_EXEC, (void *) &pe);
799 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
800 } else
801 PROC_UNLOCK(p);
802 #else /* !HWPMC_HOOKS */
803 PROC_UNLOCK(p);
804 #endif
805
806 /* Set values passed into the program in registers. */
807 if (p->p_sysent->sv_setregs)
808 (*p->p_sysent->sv_setregs)(td, imgp->entry_addr,
809 (u_long)(uintptr_t)stack_base, imgp->ps_strings);
810 else
811 exec_setregs(td, imgp->entry_addr,
812 (u_long)(uintptr_t)stack_base, imgp->ps_strings);
813
814 vfs_mark_atime(imgp->vp, td->td_ucred);
815
816 SDT_PROBE(proc, kernel, , exec_success, args->fname, 0, 0, 0, 0);
817
818 done1:
819 /*
820 * Free any resources malloc'd earlier that we didn't use.
821 */
822 uifree(euip);
823 if (newcred == NULL)
824 crfree(oldcred);
825 else
826 crfree(newcred);
827 VOP_UNLOCK(imgp->vp, 0);
828
829 /*
830 * Handle deferred decrement of ref counts.
831 */
832 if (textvp != NULL) {
833 int tvfslocked;
834
835 tvfslocked = VFS_LOCK_GIANT(textvp->v_mount);
836 vrele(textvp);
837 VFS_UNLOCK_GIANT(tvfslocked);
838 }
839 if (binvp && error != 0)
840 vrele(binvp);
841 #ifdef KTRACE
842 if (tracevp != NULL) {
843 int tvfslocked;
844
845 tvfslocked = VFS_LOCK_GIANT(tracevp->v_mount);
846 vrele(tracevp);
847 VFS_UNLOCK_GIANT(tvfslocked);
848 }
849 if (tracecred != NULL)
850 crfree(tracecred);
851 #endif
852 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
853 pargs_drop(oldargs);
854 pargs_drop(newargs);
855 if (oldsigacts != NULL)
856 sigacts_free(oldsigacts);
857
858 exec_fail_dealloc:
859
860 /*
861 * free various allocated resources
862 */
863 if (imgp->firstpage != NULL)
864 exec_unmap_first_page(imgp);
865
866 if (imgp->vp != NULL) {
867 if (args->fname)
868 NDFREE(&nd, NDF_ONLY_PNBUF);
869 if (imgp->opened)
870 VOP_CLOSE(imgp->vp, FREAD, td->td_ucred, td);
871 vput(imgp->vp);
872 }
873
874 if (imgp->object != NULL)
875 vm_object_deallocate(imgp->object);
876
877 free(imgp->freepath, M_TEMP);
878
879 if (error == 0) {
880 /*
881 * Stop the process here if its stop event mask has
882 * the S_EXEC bit set.
883 */
884 STOPEVENT(p, S_EXEC, 0);
885 goto done2;
886 }
887
888 exec_fail:
889 /* we're done here, clear P_INEXEC */
890 PROC_LOCK(p);
891 p->p_flag &= ~P_INEXEC;
892 PROC_UNLOCK(p);
893
894 SDT_PROBE(proc, kernel, , exec_failure, error, 0, 0, 0, 0);
895
896 done2:
897 #ifdef MAC
898 mac_execve_exit(imgp);
899 mac_execve_interpreter_exit(interpvplabel);
900 #endif
901 VFS_UNLOCK_GIANT(vfslocked);
902 exec_free_args(args);
903
904 if (error && imgp->vmspace_destroyed) {
905 /* sorry, no more process anymore. exit gracefully */
906 exit1(td, W_EXITCODE(0, SIGABRT));
907 /* NOT REACHED */
908 }
909 return (error);
910 }
911
912 int
913 exec_map_first_page(imgp)
914 struct image_params *imgp;
915 {
916 int rv, i;
917 int initial_pagein;
918 vm_page_t ma[VM_INITIAL_PAGEIN];
919 vm_object_t object;
920
921 if (imgp->firstpage != NULL)
922 exec_unmap_first_page(imgp);
923
924 object = imgp->vp->v_object;
925 if (object == NULL)
926 return (EACCES);
927 VM_OBJECT_LOCK(object);
928 #if VM_NRESERVLEVEL > 0
929 if ((object->flags & OBJ_COLORED) == 0) {
930 object->flags |= OBJ_COLORED;
931 object->pg_color = 0;
932 }
933 #endif
934 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
935 if (ma[0]->valid != VM_PAGE_BITS_ALL) {
936 initial_pagein = VM_INITIAL_PAGEIN;
937 if (initial_pagein > object->size)
938 initial_pagein = object->size;
939 for (i = 1; i < initial_pagein; i++) {
940 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
941 if (ma[i]->valid)
942 break;
943 if ((ma[i]->oflags & VPO_BUSY) || ma[i]->busy)
944 break;
945 vm_page_busy(ma[i]);
946 } else {
947 ma[i] = vm_page_alloc(object, i,
948 VM_ALLOC_NORMAL | VM_ALLOC_IFNOTCACHED);
949 if (ma[i] == NULL)
950 break;
951 }
952 }
953 initial_pagein = i;
954 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
955 ma[0] = vm_page_lookup(object, 0);
956 if ((rv != VM_PAGER_OK) || (ma[0] == NULL)) {
957 if (ma[0]) {
958 vm_page_lock_queues();
959 vm_page_free(ma[0]);
960 vm_page_unlock_queues();
961 }
962 VM_OBJECT_UNLOCK(object);
963 return (EIO);
964 }
965 }
966 vm_page_lock_queues();
967 vm_page_hold(ma[0]);
968 vm_page_unlock_queues();
969 vm_page_wakeup(ma[0]);
970 VM_OBJECT_UNLOCK(object);
971
972 imgp->firstpage = sf_buf_alloc(ma[0], 0);
973 imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
974
975 return (0);
976 }
977
978 void
979 exec_unmap_first_page(imgp)
980 struct image_params *imgp;
981 {
982 vm_page_t m;
983
984 if (imgp->firstpage != NULL) {
985 m = sf_buf_page(imgp->firstpage);
986 sf_buf_free(imgp->firstpage);
987 imgp->firstpage = NULL;
988 vm_page_lock_queues();
989 vm_page_unhold(m);
990 vm_page_unlock_queues();
991 }
992 }
993
994 /*
995 * Destroy old address space, and allocate a new stack
996 * The new stack is only SGROWSIZ large because it is grown
997 * automatically in trap.c.
998 */
999 int
1000 exec_new_vmspace(imgp, sv)
1001 struct image_params *imgp;
1002 struct sysentvec *sv;
1003 {
1004 int error;
1005 struct proc *p = imgp->proc;
1006 struct vmspace *vmspace = p->p_vmspace;
1007 vm_offset_t sv_minuser, stack_addr;
1008 vm_map_t map;
1009 u_long ssiz;
1010
1011 imgp->vmspace_destroyed = 1;
1012 imgp->sysent = sv;
1013
1014 /* May be called with Giant held */
1015 EVENTHANDLER_INVOKE(process_exec, p, imgp);
1016
1017 /*
1018 * Blow away entire process VM, if address space not shared,
1019 * otherwise, create a new VM space so that other threads are
1020 * not disrupted
1021 */
1022 map = &vmspace->vm_map;
1023 if (map_at_zero)
1024 sv_minuser = sv->sv_minuser;
1025 else
1026 sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
1027 if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
1028 vm_map_max(map) == sv->sv_maxuser) {
1029 shmexit(vmspace);
1030 pmap_remove_pages(vmspace_pmap(vmspace));
1031 vm_map_remove(map, vm_map_min(map), vm_map_max(map));
1032 } else {
1033 error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
1034 if (error)
1035 return (error);
1036 vmspace = p->p_vmspace;
1037 map = &vmspace->vm_map;
1038 }
1039
1040 /* Allocate a new stack */
1041 if (sv->sv_maxssiz != NULL)
1042 ssiz = *sv->sv_maxssiz;
1043 else
1044 ssiz = maxssiz;
1045 stack_addr = sv->sv_usrstack - ssiz;
1046 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1047 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_DOWN);
1048 if (error)
1049 return (error);
1050
1051 #ifdef __ia64__
1052 /* Allocate a new register stack */
1053 stack_addr = IA64_BACKINGSTORE;
1054 error = vm_map_stack(map, stack_addr, (vm_size_t)ssiz,
1055 sv->sv_stackprot, VM_PROT_ALL, MAP_STACK_GROWS_UP);
1056 if (error)
1057 return (error);
1058 #endif
1059
1060 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
1061 * VM_STACK case, but they are still used to monitor the size of the
1062 * process stack so we can check the stack rlimit.
1063 */
1064 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
1065 vmspace->vm_maxsaddr = (char *)sv->sv_usrstack - ssiz;
1066
1067 return (0);
1068 }
1069
1070 /*
1071 * Copy out argument and environment strings from the old process address
1072 * space into the temporary string buffer.
1073 */
1074 int
1075 exec_copyin_args(struct image_args *args, char *fname,
1076 enum uio_seg segflg, char **argv, char **envv)
1077 {
1078 char *argp, *envp;
1079 int error;
1080 size_t length;
1081
1082 bzero(args, sizeof(*args));
1083 if (argv == NULL)
1084 return (EFAULT);
1085 /*
1086 * Allocate temporary demand zeroed space for argument and
1087 * environment strings:
1088 *
1089 * o ARG_MAX for argument and environment;
1090 * o MAXSHELLCMDLEN for the name of interpreters.
1091 */
1092 args->buf = (char *) kmem_alloc_wait(exec_map,
1093 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1094 if (args->buf == NULL)
1095 return (ENOMEM);
1096 args->begin_argv = args->buf;
1097 args->endp = args->begin_argv;
1098 args->stringspace = ARG_MAX;
1099 /*
1100 * Copy the file name.
1101 */
1102 if (fname != NULL) {
1103 args->fname = args->buf + ARG_MAX;
1104 error = (segflg == UIO_SYSSPACE) ?
1105 copystr(fname, args->fname, PATH_MAX, &length) :
1106 copyinstr(fname, args->fname, PATH_MAX, &length);
1107 if (error != 0)
1108 goto err_exit;
1109 } else
1110 args->fname = NULL;
1111
1112 /*
1113 * extract arguments first
1114 */
1115 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
1116 if (argp == (caddr_t) -1) {
1117 error = EFAULT;
1118 goto err_exit;
1119 }
1120 if ((error = copyinstr(argp, args->endp,
1121 args->stringspace, &length))) {
1122 if (error == ENAMETOOLONG)
1123 error = E2BIG;
1124 goto err_exit;
1125 }
1126 args->stringspace -= length;
1127 args->endp += length;
1128 args->argc++;
1129 }
1130
1131 args->begin_envv = args->endp;
1132
1133 /*
1134 * extract environment strings
1135 */
1136 if (envv) {
1137 while ((envp = (caddr_t)(intptr_t)fuword(envv++))) {
1138 if (envp == (caddr_t)-1) {
1139 error = EFAULT;
1140 goto err_exit;
1141 }
1142 if ((error = copyinstr(envp, args->endp,
1143 args->stringspace, &length))) {
1144 if (error == ENAMETOOLONG)
1145 error = E2BIG;
1146 goto err_exit;
1147 }
1148 args->stringspace -= length;
1149 args->endp += length;
1150 args->envc++;
1151 }
1152 }
1153
1154 return (0);
1155
1156 err_exit:
1157 exec_free_args(args);
1158 return (error);
1159 }
1160
1161 static void
1162 exec_free_args(struct image_args *args)
1163 {
1164
1165 if (args->buf) {
1166 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf,
1167 PATH_MAX + ARG_MAX + MAXSHELLCMDLEN);
1168 args->buf = NULL;
1169 }
1170 }
1171
1172 /*
1173 * Copy strings out to the new process address space, constructing new arg
1174 * and env vector tables. Return a pointer to the base so that it can be used
1175 * as the initial stack pointer.
1176 */
1177 register_t *
1178 exec_copyout_strings(imgp)
1179 struct image_params *imgp;
1180 {
1181 int argc, envc;
1182 char **vectp;
1183 char *stringp, *destp;
1184 register_t *stack_base;
1185 struct ps_strings *arginfo;
1186 struct proc *p;
1187 size_t execpath_len;
1188 int szsigcode;
1189
1190 /*
1191 * Calculate string base and vector table pointers.
1192 * Also deal with signal trampoline code for this exec type.
1193 */
1194 if (imgp->execpath != NULL && imgp->auxargs != NULL)
1195 execpath_len = strlen(imgp->execpath) + 1;
1196 else
1197 execpath_len = 0;
1198 p = imgp->proc;
1199 szsigcode = 0;
1200 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
1201 if (p->p_sysent->sv_szsigcode != NULL)
1202 szsigcode = *(p->p_sysent->sv_szsigcode);
1203 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
1204 roundup(execpath_len, sizeof(char *)) -
1205 roundup((ARG_MAX - imgp->args->stringspace), sizeof(char *));
1206
1207 /*
1208 * install sigcode
1209 */
1210 if (szsigcode)
1211 copyout(p->p_sysent->sv_sigcode, ((caddr_t)arginfo -
1212 szsigcode), szsigcode);
1213
1214 /*
1215 * Copy the image path for the rtld.
1216 */
1217 if (execpath_len != 0) {
1218 imgp->execpathp = (uintptr_t)arginfo - szsigcode - execpath_len;
1219 copyout(imgp->execpath, (void *)imgp->execpathp,
1220 execpath_len);
1221 }
1222
1223 /*
1224 * If we have a valid auxargs ptr, prepare some room
1225 * on the stack.
1226 */
1227 if (imgp->auxargs) {
1228 /*
1229 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
1230 * lower compatibility.
1231 */
1232 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
1233 (AT_COUNT * 2);
1234 /*
1235 * The '+ 2' is for the null pointers at the end of each of
1236 * the arg and env vector sets,and imgp->auxarg_size is room
1237 * for argument of Runtime loader.
1238 */
1239 vectp = (char **)(destp - (imgp->args->argc +
1240 imgp->args->envc + 2 + imgp->auxarg_size + execpath_len) *
1241 sizeof(char *));
1242 } else {
1243 /*
1244 * The '+ 2' is for the null pointers at the end of each of
1245 * the arg and env vector sets
1246 */
1247 vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
1248 sizeof(char *));
1249 }
1250
1251 /*
1252 * vectp also becomes our initial stack base
1253 */
1254 stack_base = (register_t *)vectp;
1255
1256 stringp = imgp->args->begin_argv;
1257 argc = imgp->args->argc;
1258 envc = imgp->args->envc;
1259
1260 /*
1261 * Copy out strings - arguments and environment.
1262 */
1263 copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
1264
1265 /*
1266 * Fill in "ps_strings" struct for ps, w, etc.
1267 */
1268 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
1269 suword(&arginfo->ps_nargvstr, argc);
1270
1271 /*
1272 * Fill in argument portion of vector table.
1273 */
1274 for (; argc > 0; --argc) {
1275 suword(vectp++, (long)(intptr_t)destp);
1276 while (*stringp++ != 0)
1277 destp++;
1278 destp++;
1279 }
1280
1281 /* a null vector table pointer separates the argp's from the envp's */
1282 suword(vectp++, 0);
1283
1284 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
1285 suword(&arginfo->ps_nenvstr, envc);
1286
1287 /*
1288 * Fill in environment portion of vector table.
1289 */
1290 for (; envc > 0; --envc) {
1291 suword(vectp++, (long)(intptr_t)destp);
1292 while (*stringp++ != 0)
1293 destp++;
1294 destp++;
1295 }
1296
1297 /* end of vector table is a null pointer */
1298 suword(vectp, 0);
1299
1300 return (stack_base);
1301 }
1302
1303 /*
1304 * Check permissions of file to execute.
1305 * Called with imgp->vp locked.
1306 * Return 0 for success or error code on failure.
1307 */
1308 int
1309 exec_check_permissions(imgp)
1310 struct image_params *imgp;
1311 {
1312 struct vnode *vp = imgp->vp;
1313 struct vattr *attr = imgp->attr;
1314 struct thread *td;
1315 int error;
1316
1317 td = curthread;
1318
1319 /* Get file attributes */
1320 error = VOP_GETATTR(vp, attr, td->td_ucred);
1321 if (error)
1322 return (error);
1323
1324 #ifdef MAC
1325 error = mac_vnode_check_exec(td->td_ucred, imgp->vp, imgp);
1326 if (error)
1327 return (error);
1328 #endif
1329
1330 /*
1331 * 1) Check if file execution is disabled for the filesystem that this
1332 * file resides on.
1333 * 2) Insure that at least one execute bit is on - otherwise root
1334 * will always succeed, and we don't want to happen unless the
1335 * file really is executable.
1336 * 3) Insure that the file is a regular file.
1337 */
1338 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
1339 ((attr->va_mode & 0111) == 0) ||
1340 (attr->va_type != VREG))
1341 return (EACCES);
1342
1343 /*
1344 * Zero length files can't be exec'd
1345 */
1346 if (attr->va_size == 0)
1347 return (ENOEXEC);
1348
1349 /*
1350 * Check for execute permission to file based on current credentials.
1351 */
1352 error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td);
1353 if (error)
1354 return (error);
1355
1356 /*
1357 * Check number of open-for-writes on the file and deny execution
1358 * if there are any.
1359 */
1360 if (vp->v_writecount)
1361 return (ETXTBSY);
1362
1363 /*
1364 * Call filesystem specific open routine (which does nothing in the
1365 * general case).
1366 */
1367 error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL);
1368 if (error == 0)
1369 imgp->opened = 1;
1370 return (error);
1371 }
1372
1373 /*
1374 * Exec handler registration
1375 */
1376 int
1377 exec_register(execsw_arg)
1378 const struct execsw *execsw_arg;
1379 {
1380 const struct execsw **es, **xs, **newexecsw;
1381 int count = 2; /* New slot and trailing NULL */
1382
1383 if (execsw)
1384 for (es = execsw; *es; es++)
1385 count++;
1386 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1387 if (newexecsw == NULL)
1388 return (ENOMEM);
1389 xs = newexecsw;
1390 if (execsw)
1391 for (es = execsw; *es; es++)
1392 *xs++ = *es;
1393 *xs++ = execsw_arg;
1394 *xs = NULL;
1395 if (execsw)
1396 free(execsw, M_TEMP);
1397 execsw = newexecsw;
1398 return (0);
1399 }
1400
1401 int
1402 exec_unregister(execsw_arg)
1403 const struct execsw *execsw_arg;
1404 {
1405 const struct execsw **es, **xs, **newexecsw;
1406 int count = 1;
1407
1408 if (execsw == NULL)
1409 panic("unregister with no handlers left?\n");
1410
1411 for (es = execsw; *es; es++) {
1412 if (*es == execsw_arg)
1413 break;
1414 }
1415 if (*es == NULL)
1416 return (ENOENT);
1417 for (es = execsw; *es; es++)
1418 if (*es != execsw_arg)
1419 count++;
1420 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
1421 if (newexecsw == NULL)
1422 return (ENOMEM);
1423 xs = newexecsw;
1424 for (es = execsw; *es; es++)
1425 if (*es != execsw_arg)
1426 *xs++ = *es;
1427 *xs = NULL;
1428 if (execsw)
1429 free(execsw, M_TEMP);
1430 execsw = newexecsw;
1431 return (0);
1432 }
Cache object: f51f6e76ba85872979d335584ee8c33a
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