Add vfork/exec perf test. exec1 tests static binaries, exec2 tests dynamic
[dragonfly.git] / sys / kern / kern_exec.c
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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 * $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 1.21 2004/03/12 23:09:36 dillon Exp $
28 */
29
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>
37#include <sys/acct.h>
38#include <sys/exec.h>
39#include <sys/imgact.h>
40#include <sys/imgact_elf.h>
41#include <sys/kern_syscall.h>
42#include <sys/wait.h>
43#include <sys/malloc.h>
44#include <sys/proc.h>
45#include <sys/signalvar.h>
46#include <sys/pioctl.h>
47#include <sys/namei.h>
48#include <sys/sysent.h>
49#include <sys/shm.h>
50#include <sys/sysctl.h>
51#include <sys/vnode.h>
52#include <sys/aio.h>
53
54#include <vm/vm.h>
55#include <vm/vm_param.h>
56#include <sys/lock.h>
57#include <vm/pmap.h>
58#include <vm/vm_page.h>
59#include <vm/vm_map.h>
60#include <vm/vm_kern.h>
61#include <vm/vm_extern.h>
62#include <vm/vm_object.h>
63#include <vm/vm_pager.h>
64
65#include <sys/user.h>
66#include <machine/reg.h>
67
68MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
69
70static register_t *exec_copyout_strings (struct image_params *);
71
72/* XXX This should be vm_size_t. */
73static u_long ps_strings = PS_STRINGS;
74SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
75
76/* XXX This should be vm_size_t. */
77static u_long usrstack = USRSTACK;
78SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
79
80u_long ps_arg_cache_limit = PAGE_SIZE / 16;
81SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
82 &ps_arg_cache_limit, 0, "");
83
84int ps_argsopen = 1;
85SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
86
87void print_execve_args(struct image_args *args);
88int debug_execve_args = 0;
89SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args,
90 0, "");
91
92void
93print_execve_args(struct image_args *args)
94{
95 char *cp;
96 int ndx;
97
98 cp = args->begin_argv;
99 for (ndx = 0; ndx < args->argc; ndx++) {
100 printf("\targv[%d]: %s\n", ndx, cp);
101 while (*cp++ != '\0');
102 }
103 for (ndx = 0; ndx < args->envc; ndx++) {
104 printf("\tenvv[%d]: %s\n", ndx, cp);
105 while (*cp++ != '\0');
106 }
107}
108
109/*
110 * Each of the items is a pointer to a `const struct execsw', hence the
111 * double pointer here.
112 */
113static const struct execsw **execsw;
114
115int
116kern_execve(struct nameidata *ndp, struct image_args *args)
117{
118 struct thread *td = curthread;
119 struct proc *p = td->td_proc;
120 register_t *stack_base;
121 int error, len, i;
122 struct image_params image_params, *imgp;
123 struct vattr attr;
124 int (*img_first) (struct image_params *);
125
126 if (debug_execve_args) {
127 printf("%s()\n", __func__);
128 print_execve_args(args);
129 }
130
131 KKASSERT(p);
132 imgp = &image_params;
133
134 /*
135 * Lock the process and set the P_INEXEC flag to indicate that
136 * it should be left alone until we're done here. This is
137 * necessary to avoid race conditions - e.g. in ptrace() -
138 * that might allow a local user to illicitly obtain elevated
139 * privileges.
140 */
141 p->p_flag |= P_INEXEC;
142
143 /*
144 * Initialize part of the common data
145 */
146 imgp->proc = p;
147 imgp->args = args;
148 imgp->attr = &attr;
149 imgp->entry_addr = 0;
150 imgp->resident = 0;
151 imgp->vmspace_destroyed = 0;
152 imgp->interpreted = 0;
153 imgp->interpreter_name[0] = 0;
154 imgp->auxargs = NULL;
155 imgp->vp = NULL;
156 imgp->firstpage = NULL;
157 imgp->ps_strings = 0;
158
159 /*
160 * Allocate temporary demand zeroed space for argument and
161 * environment strings
162 */
163 imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
164 if (imgp->image_header == NULL) {
165 error = ENOMEM;
166 goto exec_fail;
167 }
168
169interpret:
170
171 /*
172 * Translate the file name. namei() returns a vnode pointer
173 * in ni_vp amoung other things.
174 */
175 error = namei(ndp);
176 if (error) {
177 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
178 PAGE_SIZE);
179 goto exec_fail;
180 }
181
182 imgp->vp = ndp->ni_vp;
183
184 /*
185 * Check file permissions (also 'opens' file)
186 */
187 error = exec_check_permissions(imgp);
188 if (error) {
189 VOP_UNLOCK(imgp->vp, NULL, 0, td);
190 goto exec_fail_dealloc;
191 }
192
193 error = exec_map_first_page(imgp);
194 VOP_UNLOCK(imgp->vp, NULL, 0, td);
195 if (error)
196 goto exec_fail_dealloc;
197
198 if (debug_execve_args && imgp->interpreted) {
199 printf(" target is interpreted -- recursive pass\n");
200 printf(" interpreter: %s\n", imgp->interpreter_name);
201 print_execve_args(args);
202 }
203
204 /*
205 * If the current process has a special image activator it
206 * wants to try first, call it. For example, emulating shell
207 * scripts differently.
208 */
209 error = -1;
210 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
211 error = img_first(imgp);
212
213 /*
214 * If the vnode has a registered vmspace, exec the vmspace
215 */
216 if (error == -1 && imgp->vp->v_resident) {
217 error = exec_resident_imgact(imgp);
218 }
219
220 /*
221 * Loop through the list of image activators, calling each one.
222 * An activator returns -1 if there is no match, 0 on success,
223 * and an error otherwise.
224 */
225 for (i = 0; error == -1 && execsw[i]; ++i) {
226 if (execsw[i]->ex_imgact == NULL ||
227 execsw[i]->ex_imgact == img_first) {
228 continue;
229 }
230 error = (*execsw[i]->ex_imgact)(imgp);
231 }
232
233 if (error) {
234 if (error == -1)
235 error = ENOEXEC;
236 goto exec_fail_dealloc;
237 }
238
239 /*
240 * Special interpreter operation, cleanup and loop up to try to
241 * activate the interpreter.
242 */
243 if (imgp->interpreted) {
244 exec_unmap_first_page(imgp);
245 /* free name buffer and old vnode */
246 NDFREE(ndp, NDF_ONLY_PNBUF);
247 vrele(ndp->ni_vp);
248 /* set new name to that of the interpreter */
249 NDINIT(ndp, NAMEI_LOOKUP,
250 CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
251 UIO_SYSSPACE, imgp->interpreter_name, td);
252 goto interpret;
253 }
254
255 /*
256 * Copy out strings (args and env) and initialize stack base
257 */
258 stack_base = exec_copyout_strings(imgp);
259 p->p_vmspace->vm_minsaddr = (char *)stack_base;
260
261 /*
262 * If custom stack fixup routine present for this process
263 * let it do the stack setup. If we are running a resident
264 * image there is no auxinfo or other image activator context
265 * so don't try to add fixups to the stack.
266 *
267 * Else stuff argument count as first item on stack
268 */
269 if (p->p_sysent->sv_fixup && imgp->resident == 0)
270 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
271 else
272 suword(--stack_base, imgp->args->argc);
273
274 /*
275 * For security and other reasons, the file descriptor table cannot
276 * be shared after an exec.
277 */
278 if (p->p_fd->fd_refcnt > 1) {
279 struct filedesc *tmp;
280
281 tmp = fdcopy(p);
282 fdfree(p);
283 p->p_fd = tmp;
284 }
285
286 /*
287 * For security and other reasons, signal handlers cannot
288 * be shared after an exec. The new proces gets a copy of the old
289 * handlers. In execsigs(), the new process will have its signals
290 * reset.
291 */
292 if (p->p_procsig->ps_refcnt > 1) {
293 struct procsig *newprocsig;
294
295 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
296 M_SUBPROC, M_WAITOK);
297 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig));
298 p->p_procsig->ps_refcnt--;
299 p->p_procsig = newprocsig;
300 p->p_procsig->ps_refcnt = 1;
301 if (p->p_sigacts == &p->p_addr->u_sigacts)
302 panic("shared procsig but private sigacts?");
303
304 p->p_addr->u_sigacts = *p->p_sigacts;
305 p->p_sigacts = &p->p_addr->u_sigacts;
306 }
307
308 /* Stop profiling */
309 stopprofclock(p);
310
311 /* close files on exec */
312 fdcloseexec(p);
313
314 /* reset caught signals */
315 execsigs(p);
316
317 /* name this process - nameiexec(p, ndp) */
318 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
319 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
320 p->p_comm[len] = 0;
321
322 /*
323 * mark as execed, wakeup the process that vforked (if any) and tell
324 * it that it now has its own resources back
325 */
326 p->p_flag |= P_EXEC;
327 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
328 p->p_flag &= ~P_PPWAIT;
329 wakeup((caddr_t)p->p_pptr);
330 }
331
332 /*
333 * Implement image setuid/setgid.
334 *
335 * Don't honor setuid/setgid if the filesystem prohibits it or if
336 * the process is being traced.
337 */
338 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
339 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
340 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
341 (p->p_flag & P_TRACED) == 0) {
342 /*
343 * Turn off syscall tracing for set-id programs, except for
344 * root. Record any set-id flags first to make sure that
345 * we do not regain any tracing during a possible block.
346 */
347 setsugid();
348 if (p->p_tracep && suser(td)) {
349 struct vnode *vtmp;
350
351 if ((vtmp = p->p_tracep) != NULL) {
352 p->p_tracep = NULL;
353 p->p_traceflag = 0;
354 vrele(vtmp);
355 }
356 }
357 /* Close any file descriptors 0..2 that reference procfs */
358 setugidsafety(p);
359 /* Make sure file descriptors 0..2 are in use. */
360 error = fdcheckstd(p);
361 if (error != 0)
362 goto exec_fail_dealloc;
363 /*
364 * Set the new credentials.
365 */
366 cratom(&p->p_ucred);
367 if (attr.va_mode & VSUID)
368 change_euid(attr.va_uid);
369 if (attr.va_mode & VSGID)
370 p->p_ucred->cr_gid = attr.va_gid;
371
372 /*
373 * Clear local varsym variables
374 */
375 varsymset_clean(&p->p_varsymset);
376 } else {
377 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
378 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
379 p->p_flag &= ~P_SUGID;
380 }
381
382 /*
383 * Implement correct POSIX saved-id behavior.
384 */
385 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
386 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
387 cratom(&p->p_ucred);
388 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
389 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
390 }
391
392 /*
393 * Store the vp for use in procfs
394 */
395 if (p->p_textvp) /* release old reference */
396 vrele(p->p_textvp);
397 VREF(ndp->ni_vp);
398 p->p_textvp = ndp->ni_vp;
399
400 /*
401 * Notify others that we exec'd, and clear the P_INEXEC flag
402 * as we're now a bona fide freshly-execed process.
403 */
404 KNOTE(&p->p_klist, NOTE_EXEC);
405 p->p_flag &= ~P_INEXEC;
406
407 /*
408 * If tracing the process, trap to debugger so breakpoints
409 * can be set before the program executes.
410 */
411 STOPEVENT(p, S_EXEC, 0);
412
413 if (p->p_flag & P_TRACED)
414 psignal(p, SIGTRAP);
415
416 /* clear "fork but no exec" flag, as we _are_ execing */
417 p->p_acflag &= ~AFORK;
418
419 /* Set values passed into the program in registers. */
420 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
421 imgp->ps_strings);
422
423 /* Free any previous argument cache */
424 if (p->p_args && --p->p_args->ar_ref == 0)
425 FREE(p->p_args, M_PARGS);
426 p->p_args = NULL;
427
428 /* Cache arguments if they fit inside our allowance */
429 i = imgp->args->begin_envv - imgp->args->begin_argv;
430 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
431 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
432 M_PARGS, M_WAITOK);
433 p->p_args->ar_ref = 1;
434 p->p_args->ar_length = i;
435 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i);
436 }
437
438exec_fail_dealloc:
439
440 /*
441 * free various allocated resources
442 */
443 if (imgp->firstpage)
444 exec_unmap_first_page(imgp);
445
446 if (imgp->image_header != NULL)
447 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
448 PAGE_SIZE);
449
450 if (imgp->vp) {
451 NDFREE(ndp, NDF_ONLY_PNBUF);
452 vrele(imgp->vp);
453 }
454
455 if (error == 0)
456 return (0);
457
458exec_fail:
459 /* we're done here, clear P_INEXEC */
460 p->p_flag &= ~P_INEXEC;
461 if (imgp->vmspace_destroyed) {
462 /* sorry, no more process anymore. exit gracefully */
463 exit1(W_EXITCODE(0, SIGABRT));
464 /* NOT REACHED */
465 return(0);
466 } else {
467 return(error);
468 }
469}
470
471/*
472 * execve() system call.
473 */
474int
475execve(struct execve_args *uap)
476{
477 struct thread *td = curthread;
478 struct nameidata nd;
479 struct image_args args;
480 int error;
481
482 NDINIT(&nd, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
483 UIO_USERSPACE, uap->fname, td);
484
485 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
486 uap->argv, uap->envv);
487 if (error == 0)
488 error = kern_execve(&nd, &args);
489
490 exec_free_args(&args);
491
492 /*
493 * The syscall result is returned in registers to the new program.
494 * Linux will register %edx as an atexit function and we must be
495 * sure to set it to 0. XXX
496 */
497 if (error == 0)
498 uap->sysmsg_result64 = 0;
499
500 return (error);
501}
502
503int
504exec_map_first_page(struct image_params *imgp)
505{
506 int s, rv, i;
507 int initial_pagein;
508 vm_page_t ma[VM_INITIAL_PAGEIN];
509 vm_object_t object;
510
511
512 if (imgp->firstpage) {
513 exec_unmap_first_page(imgp);
514 }
515
516 VOP_GETVOBJECT(imgp->vp, &object);
517 s = splvm();
518
519 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
520
521 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
522 initial_pagein = VM_INITIAL_PAGEIN;
523 if (initial_pagein > object->size)
524 initial_pagein = object->size;
525 for (i = 1; i < initial_pagein; i++) {
526 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
527 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy)
528 break;
529 if (ma[i]->valid)
530 break;
531 vm_page_busy(ma[i]);
532 } else {
533 ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
534 if (ma[i] == NULL)
535 break;
536 }
537 }
538 initial_pagein = i;
539
540 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
541 ma[0] = vm_page_lookup(object, 0);
542
543 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) {
544 if (ma[0]) {
545 vm_page_protect(ma[0], VM_PROT_NONE);
546 vm_page_free(ma[0]);
547 }
548 splx(s);
549 return EIO;
550 }
551 }
552
553 vm_page_wire(ma[0]);
554 vm_page_wakeup(ma[0]);
555 splx(s);
556
557 pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0]));
558 imgp->firstpage = ma[0];
559
560 return 0;
561}
562
563void
564exec_unmap_first_page(imgp)
565 struct image_params *imgp;
566{
567 if (imgp->firstpage) {
568 pmap_kremove((vm_offset_t) imgp->image_header);
569 vm_page_unwire(imgp->firstpage, 1);
570 imgp->firstpage = NULL;
571 }
572}
573
574/*
575 * Destroy old address space, and allocate a new stack
576 * The new stack is only SGROWSIZ large because it is grown
577 * automatically in trap.c.
578 */
579int
580exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy)
581{
582 int error;
583 struct vmspace *vmspace = imgp->proc->p_vmspace;
584 vm_offset_t stack_addr = USRSTACK - maxssiz;
585 vm_map_t map;
586
587 imgp->vmspace_destroyed = 1;
588
589 /*
590 * Prevent a pending AIO from modifying the new address space.
591 */
592 aio_proc_rundown(imgp->proc);
593
594 /*
595 * Blow away entire process VM, if address space not shared,
596 * otherwise, create a new VM space so that other threads are
597 * not disrupted. If we are execing a resident vmspace we
598 * create a duplicate of it and remap the stack.
599 *
600 * The exitingcnt test is not strictly necessary but has been
601 * included for code sanity (to make the code more deterministic).
602 */
603 map = &vmspace->vm_map;
604 if (vmcopy) {
605 vmspace_exec(imgp->proc, vmcopy);
606 vmspace = imgp->proc->p_vmspace;
607 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK);
608 map = &vmspace->vm_map;
609 } else if (vmspace->vm_refcnt == 1 && vmspace->vm_exitingcnt == 0) {
610 shmexit(vmspace);
611 if (vmspace->vm_upcalls)
612 upc_release(vmspace, imgp->proc);
613 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
614 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
615 } else {
616 vmspace_exec(imgp->proc, NULL);
617 vmspace = imgp->proc->p_vmspace;
618 map = &vmspace->vm_map;
619 }
620
621 /* Allocate a new stack */
622 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
623 VM_PROT_ALL, VM_PROT_ALL, 0);
624 if (error)
625 return (error);
626
627 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
628 * VM_STACK case, but they are still used to monitor the size of the
629 * process stack so we can check the stack rlimit.
630 */
631 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
632 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
633
634 return(0);
635}
636
637/*
638 * Copy out argument and environment strings from the old process
639 * address space into the temporary string buffer.
640 */
641int
642exec_copyin_args(struct image_args *args, char *fname,
643 enum exec_path_segflg segflg, char **argv, char **envv)
644{
645 char *argp, *envp;
646 int error = 0;
647 size_t length;
648
649 bzero(args, sizeof(*args));
650 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
651 if (args->buf == NULL)
652 return (ENOMEM);
653 args->begin_argv = args->buf;
654 args->endp = args->begin_argv;
655 args->space = ARG_MAX;
656
657 args->fname = args->buf + ARG_MAX;
658
659 /*
660 * Copy the file name.
661 */
662 if (segflg == PATH_SYSSPACE) {
663 error = copystr(fname, args->fname, PATH_MAX, &length);
664 } else if (segflg == PATH_USERSPACE) {
665 error = copyinstr(fname, args->fname, PATH_MAX, &length);
666 }
667
668 /*
669 * extract argument strings
670 */
671
672 if (argv && error == 0) {
673 /*
674 * The argv0 argument for execv() is allowed to be NULL,
675 * in which case we use our filename as argv[0].
676 * This guarantees that
677 * the interpreter knows what file to open in the case
678 * that we exec an interpreted file.
679 */
680 argp = (caddr_t) (intptr_t) fuword(argv);
681 if (argp == NULL) {
682 length = strlen(args->fname) + 1;
683 KKASSERT(length <= args->space);
684 bcopy(args->fname, args->endp, length);
685 args->space -= length;
686 args->endp += length;
687 args->argc++;
688 argv++;
689 }
690 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
691 if (argp == (caddr_t) -1) {
692 error = EFAULT;
693 goto cleanup;
694 }
695 error = copyinstr(argp, args->endp,
696 args->space, &length);
697 if (error == ENAMETOOLONG)
698 error = E2BIG;
699 if (error)
700 goto cleanup;
701 args->space -= length;
702 args->endp += length;
703 args->argc++;
704 }
705 }
706
707 args->begin_envv = args->endp;
708
709 /*
710 * extract environment strings
711 */
712 if (envv && error == 0) {
713 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
714 if (envp == (caddr_t) -1) {
715 error = EFAULT;
716 goto cleanup;
717 }
718 error = copyinstr(envp, args->endp, args->space,
719 &length);
720 if (error == ENAMETOOLONG)
721 error = E2BIG;
722 if (error)
723 goto cleanup;
724 args->space -= length;
725 args->endp += length;
726 args->envc++;
727 }
728 }
729
730cleanup:
731 return (error);
732}
733
734void
735exec_free_args(struct image_args *args)
736{
737 if (args->buf) {
738 kmem_free_wakeup(exec_map,
739 (vm_offset_t)args->buf, PATH_MAX + ARG_MAX);
740 args->buf = NULL;
741 }
742}
743
744/*
745 * Copy strings out to the new process address space, constructing
746 * new arg and env vector tables. Return a pointer to the base
747 * so that it can be used as the initial stack pointer.
748 */
749register_t *
750exec_copyout_strings(struct image_params *imgp)
751{
752 int argc, envc;
753 char **vectp;
754 char *stringp, *destp;
755 register_t *stack_base;
756 struct ps_strings *arginfo;
757 int szsigcode;
758
759 /*
760 * Calculate string base and vector table pointers.
761 * Also deal with signal trampoline code for this exec type.
762 */
763 arginfo = (struct ps_strings *)PS_STRINGS;
764 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
765 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
766 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
767
768 /*
769 * install sigcode
770 */
771 if (szsigcode)
772 copyout(imgp->proc->p_sysent->sv_sigcode,
773 ((caddr_t)arginfo - szsigcode), szsigcode);
774
775 /*
776 * If we have a valid auxargs ptr, prepare some room
777 * on the stack.
778 *
779 * The '+ 2' is for the null pointers at the end of each of the
780 * arg and env vector sets, and 'AT_COUNT*2' is room for the
781 * ELF Auxargs data.
782 */
783 if (imgp->auxargs) {
784 vectp = (char **)(destp - (imgp->args->argc +
785 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*));
786 } else {
787 vectp = (char **)(destp - (imgp->args->argc +
788 imgp->args->envc + 2) * sizeof(char*));
789 }
790
791 /*
792 * NOTE: don't bother aligning the stack here for GCC 2.x, it will
793 * be done in crt1.o. Note that GCC 3.x aligns the stack in main.
794 */
795
796 /*
797 * vectp also becomes our initial stack base
798 */
799 stack_base = (register_t *)vectp;
800
801 stringp = imgp->args->begin_argv;
802 argc = imgp->args->argc;
803 envc = imgp->args->envc;
804
805 /*
806 * Copy out strings - arguments and environment.
807 */
808 copyout(stringp, destp, ARG_MAX - imgp->args->space);
809
810 /*
811 * Fill in "ps_strings" struct for ps, w, etc.
812 */
813 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
814 suword(&arginfo->ps_nargvstr, argc);
815
816 /*
817 * Fill in argument portion of vector table.
818 */
819 for (; argc > 0; --argc) {
820 suword(vectp++, (long)(intptr_t)destp);
821 while (*stringp++ != 0)
822 destp++;
823 destp++;
824 }
825
826 /* a null vector table pointer separates the argp's from the envp's */
827 suword(vectp++, 0);
828
829 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
830 suword(&arginfo->ps_nenvstr, envc);
831
832 /*
833 * Fill in environment portion of vector table.
834 */
835 for (; envc > 0; --envc) {
836 suword(vectp++, (long)(intptr_t)destp);
837 while (*stringp++ != 0)
838 destp++;
839 destp++;
840 }
841
842 /* end of vector table is a null pointer */
843 suword(vectp, 0);
844
845 return (stack_base);
846}
847
848/*
849 * Check permissions of file to execute.
850 * Return 0 for success or error code on failure.
851 */
852int
853exec_check_permissions(imgp)
854 struct image_params *imgp;
855{
856 struct proc *p = imgp->proc;
857 struct vnode *vp = imgp->vp;
858 struct vattr *attr = imgp->attr;
859 struct thread *td = p->p_thread;
860 int error;
861
862 /* Get file attributes */
863 error = VOP_GETATTR(vp, attr, td);
864 if (error)
865 return (error);
866
867 /*
868 * 1) Check if file execution is disabled for the filesystem that this
869 * file resides on.
870 * 2) Insure that at least one execute bit is on - otherwise root
871 * will always succeed, and we don't want to happen unless the
872 * file really is executable.
873 * 3) Insure that the file is a regular file.
874 */
875 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
876 ((attr->va_mode & 0111) == 0) ||
877 (attr->va_type != VREG)) {
878 return (EACCES);
879 }
880
881 /*
882 * Zero length files can't be exec'd
883 */
884 if (attr->va_size == 0)
885 return (ENOEXEC);
886
887 /*
888 * Check for execute permission to file based on current credentials.
889 */
890 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td);
891 if (error)
892 return (error);
893
894 /*
895 * Check number of open-for-writes on the file and deny execution
896 * if there are any.
897 */
898 if (vp->v_writecount)
899 return (ETXTBSY);
900
901 /*
902 * Call filesystem specific open routine (which does nothing in the
903 * general case).
904 */
905 error = VOP_OPEN(vp, FREAD, p->p_ucred, td);
906 if (error)
907 return (error);
908
909 return (0);
910}
911
912/*
913 * Exec handler registration
914 */
915int
916exec_register(execsw_arg)
917 const struct execsw *execsw_arg;
918{
919 const struct execsw **es, **xs, **newexecsw;
920 int count = 2; /* New slot and trailing NULL */
921
922 if (execsw)
923 for (es = execsw; *es; es++)
924 count++;
925 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
926 if (newexecsw == NULL)
927 return ENOMEM;
928 xs = newexecsw;
929 if (execsw)
930 for (es = execsw; *es; es++)
931 *xs++ = *es;
932 *xs++ = execsw_arg;
933 *xs = NULL;
934 if (execsw)
935 free(execsw, M_TEMP);
936 execsw = newexecsw;
937 return 0;
938}
939
940int
941exec_unregister(execsw_arg)
942 const struct execsw *execsw_arg;
943{
944 const struct execsw **es, **xs, **newexecsw;
945 int count = 1;
946
947 if (execsw == NULL)
948 panic("unregister with no handlers left?\n");
949
950 for (es = execsw; *es; es++) {
951 if (*es == execsw_arg)
952 break;
953 }
954 if (*es == NULL)
955 return ENOENT;
956 for (es = execsw; *es; es++)
957 if (*es != execsw_arg)
958 count++;
959 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
960 if (newexecsw == NULL)
961 return ENOMEM;
962 xs = newexecsw;
963 for (es = execsw; *es; es++)
964 if (*es != execsw_arg)
965 *xs++ = *es;
966 *xs = NULL;
967 if (execsw)
968 free(execsw, M_TEMP);
969 execsw = newexecsw;
970 return 0;
971}