proc->thread stage 3.5: Add an IO_CORE flag so coda doesn't have to dig
[dragonfly.git] / sys / kern / kern_exec.c
CommitLineData
984263bc
MD
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 $
41c20dac 27 * $DragonFly: src/sys/kern/kern_exec.c,v 1.3 2003/06/23 17:55:41 dillon Exp $
984263bc
MD
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/wait.h>
42#include <sys/malloc.h>
43#include <sys/proc.h>
44#include <sys/signalvar.h>
45#include <sys/pioctl.h>
46#include <sys/namei.h>
47#include <sys/sysent.h>
48#include <sys/shm.h>
49#include <sys/sysctl.h>
50#include <sys/vnode.h>
51#include <sys/aio.h>
52
53#include <vm/vm.h>
54#include <vm/vm_param.h>
55#include <sys/lock.h>
56#include <vm/pmap.h>
57#include <vm/vm_page.h>
58#include <vm/vm_map.h>
59#include <vm/vm_kern.h>
60#include <vm/vm_extern.h>
61#include <vm/vm_object.h>
62#include <vm/vm_pager.h>
63
64#include <sys/user.h>
65#include <machine/reg.h>
66
67MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments");
68
69static register_t *exec_copyout_strings __P((struct image_params *));
70
71/* XXX This should be vm_size_t. */
72static u_long ps_strings = PS_STRINGS;
73SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, "");
74
75/* XXX This should be vm_size_t. */
76static u_long usrstack = USRSTACK;
77SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, "");
78
79u_long ps_arg_cache_limit = PAGE_SIZE / 16;
80SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW,
81 &ps_arg_cache_limit, 0, "");
82
83int ps_argsopen = 1;
84SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, "");
85
86/*
87 * Each of the items is a pointer to a `const struct execsw', hence the
88 * double pointer here.
89 */
90static const struct execsw **execsw;
91
92#ifndef _SYS_SYSPROTO_H_
93struct execve_args {
94 char *fname;
95 char **argv;
96 char **envv;
97};
98#endif
99
100/*
101 * execve() system call.
102 */
103int
41c20dac 104execve(struct execve_args *uap)
984263bc 105{
41c20dac 106 struct proc *p = curproc;
984263bc
MD
107 struct nameidata nd, *ndp;
108 register_t *stack_base;
109 int error, len, i;
110 struct image_params image_params, *imgp;
111 struct vattr attr;
112 int (*img_first) __P((struct image_params *));
113
114 imgp = &image_params;
115
116 /*
117 * Lock the process and set the P_INEXEC flag to indicate that
118 * it should be left alone until we're done here. This is
119 * necessary to avoid race conditions - e.g. in ptrace() -
120 * that might allow a local user to illicitly obtain elevated
121 * privileges.
122 */
123 p->p_flag |= P_INEXEC;
124
125 /*
126 * Initialize part of the common data
127 */
128 imgp->proc = p;
129 imgp->uap = uap;
130 imgp->attr = &attr;
131 imgp->argc = imgp->envc = 0;
132 imgp->argv0 = NULL;
133 imgp->entry_addr = 0;
134 imgp->vmspace_destroyed = 0;
135 imgp->interpreted = 0;
136 imgp->interpreter_name[0] = '\0';
137 imgp->auxargs = NULL;
138 imgp->vp = NULL;
139 imgp->firstpage = NULL;
140 imgp->ps_strings = 0;
141
142 /*
143 * Allocate temporary demand zeroed space for argument and
144 * environment strings
145 */
146 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + PAGE_SIZE);
147 if (imgp->stringbase == NULL) {
148 error = ENOMEM;
149 goto exec_fail;
150 }
151 imgp->stringp = imgp->stringbase;
152 imgp->stringspace = ARG_MAX;
153 imgp->image_header = imgp->stringbase + ARG_MAX;
154
155 /*
156 * Translate the file name. namei() returns a vnode pointer
157 * in ni_vp amoung other things.
158 */
159 ndp = &nd;
160 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
161 UIO_USERSPACE, uap->fname, p);
162
163interpret:
164
165 error = namei(ndp);
166 if (error) {
167 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
168 ARG_MAX + PAGE_SIZE);
169 goto exec_fail;
170 }
171
172 imgp->vp = ndp->ni_vp;
173 imgp->fname = uap->fname;
174
175 /*
176 * Check file permissions (also 'opens' file)
177 */
178 error = exec_check_permissions(imgp);
179 if (error) {
180 VOP_UNLOCK(imgp->vp, 0, p);
181 goto exec_fail_dealloc;
182 }
183
184 error = exec_map_first_page(imgp);
185 VOP_UNLOCK(imgp->vp, 0, p);
186 if (error)
187 goto exec_fail_dealloc;
188
189 /*
190 * If the current process has a special image activator it
191 * wants to try first, call it. For example, emulating shell
192 * scripts differently.
193 */
194 error = -1;
195 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
196 error = img_first(imgp);
197
198 /*
199 * Loop through the list of image activators, calling each one.
200 * An activator returns -1 if there is no match, 0 on success,
201 * and an error otherwise.
202 */
203 for (i = 0; error == -1 && execsw[i]; ++i) {
204 if (execsw[i]->ex_imgact == NULL ||
205 execsw[i]->ex_imgact == img_first) {
206 continue;
207 }
208 error = (*execsw[i]->ex_imgact)(imgp);
209 }
210
211 if (error) {
212 if (error == -1)
213 error = ENOEXEC;
214 goto exec_fail_dealloc;
215 }
216
217 /*
218 * Special interpreter operation, cleanup and loop up to try to
219 * activate the interpreter.
220 */
221 if (imgp->interpreted) {
222 exec_unmap_first_page(imgp);
223 /* free name buffer and old vnode */
224 NDFREE(ndp, NDF_ONLY_PNBUF);
225 vrele(ndp->ni_vp);
226 /* set new name to that of the interpreter */
227 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME,
228 UIO_SYSSPACE, imgp->interpreter_name, p);
229 goto interpret;
230 }
231
232 /*
233 * Copy out strings (args and env) and initialize stack base
234 */
235 stack_base = exec_copyout_strings(imgp);
236 p->p_vmspace->vm_minsaddr = (char *)stack_base;
237
238 /*
239 * If custom stack fixup routine present for this process
240 * let it do the stack setup.
241 * Else stuff argument count as first item on stack
242 */
243 if (p->p_sysent->sv_fixup)
244 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
245 else
246 suword(--stack_base, imgp->argc);
247
248 /*
249 * For security and other reasons, the file descriptor table cannot
250 * be shared after an exec.
251 */
252 if (p->p_fd->fd_refcnt > 1) {
253 struct filedesc *tmp;
254
255 tmp = fdcopy(p);
256 fdfree(p);
257 p->p_fd = tmp;
258 }
259
260 /*
261 * For security and other reasons, signal handlers cannot
262 * be shared after an exec. The new proces gets a copy of the old
263 * handlers. In execsigs(), the new process will have its signals
264 * reset.
265 */
266 if (p->p_procsig->ps_refcnt > 1) {
267 struct procsig *newprocsig;
268
269 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
270 M_SUBPROC, M_WAITOK);
271 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig));
272 p->p_procsig->ps_refcnt--;
273 p->p_procsig = newprocsig;
274 p->p_procsig->ps_refcnt = 1;
275 if (p->p_sigacts == &p->p_addr->u_sigacts)
276 panic("shared procsig but private sigacts?");
277
278 p->p_addr->u_sigacts = *p->p_sigacts;
279 p->p_sigacts = &p->p_addr->u_sigacts;
280 }
281
282 /* Stop profiling */
283 stopprofclock(p);
284
285 /* close files on exec */
286 fdcloseexec(p);
287
288 /* reset caught signals */
289 execsigs(p);
290
291 /* name this process - nameiexec(p, ndp) */
292 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
293 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
294 p->p_comm[len] = 0;
295
296 /*
297 * mark as execed, wakeup the process that vforked (if any) and tell
298 * it that it now has its own resources back
299 */
300 p->p_flag |= P_EXEC;
301 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
302 p->p_flag &= ~P_PPWAIT;
303 wakeup((caddr_t)p->p_pptr);
304 }
305
306 /*
307 * Implement image setuid/setgid.
308 *
309 * Don't honor setuid/setgid if the filesystem prohibits it or if
310 * the process is being traced.
311 */
312 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
313 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
314 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
315 (p->p_flag & P_TRACED) == 0) {
316 /*
317 * Turn off syscall tracing for set-id programs, except for
318 * root. Record any set-id flags first to make sure that
319 * we do not regain any tracing during a possible block.
320 */
41c20dac
MD
321 setsugid();
322 if (p->p_tracep && suser()) {
984263bc
MD
323 struct vnode *vtmp;
324
325 if ((vtmp = p->p_tracep) != NULL) {
326 p->p_tracep = NULL;
327 p->p_traceflag = 0;
328 vrele(vtmp);
329 }
330 }
331 /* Close any file descriptors 0..2 that reference procfs */
332 setugidsafety(p);
333 /* Make sure file descriptors 0..2 are in use. */
334 error = fdcheckstd(p);
335 if (error != 0)
336 goto exec_fail_dealloc;
337 /*
338 * Set the new credentials.
339 */
340 p->p_ucred = crcopy(p->p_ucred);
341 if (attr.va_mode & VSUID)
41c20dac 342 change_euid(attr.va_uid);
984263bc
MD
343 if (attr.va_mode & VSGID)
344 p->p_ucred->cr_gid = attr.va_gid;
345 } else {
41c20dac
MD
346 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
347 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
984263bc
MD
348 p->p_flag &= ~P_SUGID;
349 }
350
351 /*
352 * Implement correct POSIX saved-id behavior.
353 */
41c20dac
MD
354 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
355 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
984263bc
MD
356
357 /*
358 * Store the vp for use in procfs
359 */
360 if (p->p_textvp) /* release old reference */
361 vrele(p->p_textvp);
362 VREF(ndp->ni_vp);
363 p->p_textvp = ndp->ni_vp;
364
365 /*
366 * Notify others that we exec'd, and clear the P_INEXEC flag
367 * as we're now a bona fide freshly-execed process.
368 */
369 KNOTE(&p->p_klist, NOTE_EXEC);
370 p->p_flag &= ~P_INEXEC;
371
372 /*
373 * If tracing the process, trap to debugger so breakpoints
374 * can be set before the program executes.
375 */
376 STOPEVENT(p, S_EXEC, 0);
377
378 if (p->p_flag & P_TRACED)
379 psignal(p, SIGTRAP);
380
381 /* clear "fork but no exec" flag, as we _are_ execing */
382 p->p_acflag &= ~AFORK;
383
384 /* Set values passed into the program in registers. */
385 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
386 imgp->ps_strings);
387
388 /* Free any previous argument cache */
389 if (p->p_args && --p->p_args->ar_ref == 0)
390 FREE(p->p_args, M_PARGS);
391 p->p_args = NULL;
392
393 /* Cache arguments if they fit inside our allowance */
394 i = imgp->endargs - imgp->stringbase;
395 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
396 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
397 M_PARGS, M_WAITOK);
398 p->p_args->ar_ref = 1;
399 p->p_args->ar_length = i;
400 bcopy(imgp->stringbase, p->p_args->ar_args, i);
401 }
402
403exec_fail_dealloc:
404
405 /*
406 * free various allocated resources
407 */
408 if (imgp->firstpage)
409 exec_unmap_first_page(imgp);
410
411 if (imgp->stringbase != NULL)
412 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase,
413 ARG_MAX + PAGE_SIZE);
414
415 if (imgp->vp) {
416 NDFREE(ndp, NDF_ONLY_PNBUF);
417 vrele(imgp->vp);
418 }
419
420 if (error == 0)
421 return (0);
422
423exec_fail:
424 /* we're done here, clear P_INEXEC */
425 p->p_flag &= ~P_INEXEC;
426 if (imgp->vmspace_destroyed) {
427 /* sorry, no more process anymore. exit gracefully */
41c20dac 428 exit1(W_EXITCODE(0, SIGABRT));
984263bc
MD
429 /* NOT REACHED */
430 return(0);
431 } else {
432 return(error);
433 }
434}
435
436int
41c20dac 437exec_map_first_page(struct image_params *imgp)
984263bc
MD
438{
439 int s, rv, i;
440 int initial_pagein;
441 vm_page_t ma[VM_INITIAL_PAGEIN];
442 vm_object_t object;
443
444
445 if (imgp->firstpage) {
446 exec_unmap_first_page(imgp);
447 }
448
449 VOP_GETVOBJECT(imgp->vp, &object);
450 s = splvm();
451
452 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
453
454 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
455 initial_pagein = VM_INITIAL_PAGEIN;
456 if (initial_pagein > object->size)
457 initial_pagein = object->size;
458 for (i = 1; i < initial_pagein; i++) {
459 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
460 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy)
461 break;
462 if (ma[i]->valid)
463 break;
464 vm_page_busy(ma[i]);
465 } else {
466 ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
467 if (ma[i] == NULL)
468 break;
469 }
470 }
471 initial_pagein = i;
472
473 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
474 ma[0] = vm_page_lookup(object, 0);
475
476 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) {
477 if (ma[0]) {
478 vm_page_protect(ma[0], VM_PROT_NONE);
479 vm_page_free(ma[0]);
480 }
481 splx(s);
482 return EIO;
483 }
484 }
485
486 vm_page_wire(ma[0]);
487 vm_page_wakeup(ma[0]);
488 splx(s);
489
490 pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0]));
491 imgp->firstpage = ma[0];
492
493 return 0;
494}
495
496void
497exec_unmap_first_page(imgp)
498 struct image_params *imgp;
499{
500 if (imgp->firstpage) {
501 pmap_kremove((vm_offset_t) imgp->image_header);
502 vm_page_unwire(imgp->firstpage, 1);
503 imgp->firstpage = NULL;
504 }
505}
506
507/*
508 * Destroy old address space, and allocate a new stack
509 * The new stack is only SGROWSIZ large because it is grown
510 * automatically in trap.c.
511 */
512int
513exec_new_vmspace(imgp)
514 struct image_params *imgp;
515{
516 int error;
517 struct vmspace *vmspace = imgp->proc->p_vmspace;
518 vm_offset_t stack_addr = USRSTACK - maxssiz;
519 vm_map_t map = &vmspace->vm_map;
520
521 imgp->vmspace_destroyed = 1;
522
523 /*
524 * Prevent a pending AIO from modifying the new address space.
525 */
526 aio_proc_rundown(imgp->proc);
527
528 /*
529 * Blow away entire process VM, if address space not shared,
530 * otherwise, create a new VM space so that other threads are
531 * not disrupted
532 */
533 if (vmspace->vm_refcnt == 1) {
534 if (vmspace->vm_shm)
535 shmexit(imgp->proc);
536 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
537 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
538 } else {
539 vmspace_exec(imgp->proc);
540 vmspace = imgp->proc->p_vmspace;
541 map = &vmspace->vm_map;
542 }
543
544 /* Allocate a new stack */
545 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
546 VM_PROT_ALL, VM_PROT_ALL, 0);
547 if (error)
548 return (error);
549
550 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
551 * VM_STACK case, but they are still used to monitor the size of the
552 * process stack so we can check the stack rlimit.
553 */
554 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
555 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
556
557 return(0);
558}
559
560/*
561 * Copy out argument and environment strings from the old process
562 * address space into the temporary string buffer.
563 */
564int
565exec_extract_strings(imgp)
566 struct image_params *imgp;
567{
568 char **argv, **envv;
569 char *argp, *envp;
570 int error;
571 size_t length;
572
573 /*
574 * extract arguments first
575 */
576
577 argv = imgp->uap->argv;
578
579 if (argv) {
580 argp = (caddr_t) (intptr_t) fuword(argv);
581 if (argp == (caddr_t) -1)
582 return (EFAULT);
583 if (argp)
584 argv++;
585 if (imgp->argv0)
586 argp = imgp->argv0;
587 if (argp) {
588 do {
589 if (argp == (caddr_t) -1)
590 return (EFAULT);
591 if ((error = copyinstr(argp, imgp->stringp,
592 imgp->stringspace, &length))) {
593 if (error == ENAMETOOLONG)
594 return(E2BIG);
595 return (error);
596 }
597 imgp->stringspace -= length;
598 imgp->stringp += length;
599 imgp->argc++;
600 } while ((argp = (caddr_t) (intptr_t) fuword(argv++)));
601 }
602 }
603
604 imgp->endargs = imgp->stringp;
605
606 /*
607 * extract environment strings
608 */
609
610 envv = imgp->uap->envv;
611
612 if (envv) {
613 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
614 if (envp == (caddr_t) -1)
615 return (EFAULT);
616 if ((error = copyinstr(envp, imgp->stringp,
617 imgp->stringspace, &length))) {
618 if (error == ENAMETOOLONG)
619 return(E2BIG);
620 return (error);
621 }
622 imgp->stringspace -= length;
623 imgp->stringp += length;
624 imgp->envc++;
625 }
626 }
627
628 return (0);
629}
630
631/*
632 * Copy strings out to the new process address space, constructing
633 * new arg and env vector tables. Return a pointer to the base
634 * so that it can be used as the initial stack pointer.
635 */
636register_t *
637exec_copyout_strings(imgp)
638 struct image_params *imgp;
639{
640 int argc, envc;
641 char **vectp;
642 char *stringp, *destp;
643 register_t *stack_base;
644 struct ps_strings *arginfo;
645 int szsigcode;
646
647 /*
648 * Calculate string base and vector table pointers.
649 * Also deal with signal trampoline code for this exec type.
650 */
651 arginfo = (struct ps_strings *)PS_STRINGS;
652 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
653 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
654 roundup((ARG_MAX - imgp->stringspace), sizeof(char *));
655
656 /*
657 * install sigcode
658 */
659 if (szsigcode)
660 copyout(imgp->proc->p_sysent->sv_sigcode,
661 ((caddr_t)arginfo - szsigcode), szsigcode);
662
663 /*
664 * If we have a valid auxargs ptr, prepare some room
665 * on the stack.
666 */
667 if (imgp->auxargs)
668 /*
669 * The '+ 2' is for the null pointers at the end of each of the
670 * arg and env vector sets, and 'AT_COUNT*2' is room for the
671 * ELF Auxargs data.
672 */
673 vectp = (char **)(destp - (imgp->argc + imgp->envc + 2 +
674 AT_COUNT*2) * sizeof(char*));
675 else
676 /*
677 * The '+ 2' is for the null pointers at the end of each of the
678 * arg and env vector sets
679 */
680 vectp = (char **)
681 (destp - (imgp->argc + imgp->envc + 2) * sizeof(char*));
682
683 /*
684 * vectp also becomes our initial stack base
685 */
686 stack_base = (register_t *)vectp;
687
688 stringp = imgp->stringbase;
689 argc = imgp->argc;
690 envc = imgp->envc;
691
692 /*
693 * Copy out strings - arguments and environment.
694 */
695 copyout(stringp, destp, ARG_MAX - imgp->stringspace);
696
697 /*
698 * Fill in "ps_strings" struct for ps, w, etc.
699 */
700 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
701 suword(&arginfo->ps_nargvstr, argc);
702
703 /*
704 * Fill in argument portion of vector table.
705 */
706 for (; argc > 0; --argc) {
707 suword(vectp++, (long)(intptr_t)destp);
708 while (*stringp++ != 0)
709 destp++;
710 destp++;
711 }
712
713 /* a null vector table pointer seperates the argp's from the envp's */
714 suword(vectp++, 0);
715
716 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
717 suword(&arginfo->ps_nenvstr, envc);
718
719 /*
720 * Fill in environment portion of vector table.
721 */
722 for (; envc > 0; --envc) {
723 suword(vectp++, (long)(intptr_t)destp);
724 while (*stringp++ != 0)
725 destp++;
726 destp++;
727 }
728
729 /* end of vector table is a null pointer */
730 suword(vectp, 0);
731
732 return (stack_base);
733}
734
735/*
736 * Check permissions of file to execute.
737 * Return 0 for success or error code on failure.
738 */
739int
740exec_check_permissions(imgp)
741 struct image_params *imgp;
742{
743 struct proc *p = imgp->proc;
744 struct vnode *vp = imgp->vp;
745 struct vattr *attr = imgp->attr;
746 int error;
747
748 /* Get file attributes */
749 error = VOP_GETATTR(vp, attr, p->p_ucred, p);
750 if (error)
751 return (error);
752
753 /*
754 * 1) Check if file execution is disabled for the filesystem that this
755 * file resides on.
756 * 2) Insure that at least one execute bit is on - otherwise root
757 * will always succeed, and we don't want to happen unless the
758 * file really is executable.
759 * 3) Insure that the file is a regular file.
760 */
761 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
762 ((attr->va_mode & 0111) == 0) ||
763 (attr->va_type != VREG)) {
764 return (EACCES);
765 }
766
767 /*
768 * Zero length files can't be exec'd
769 */
770 if (attr->va_size == 0)
771 return (ENOEXEC);
772
773 /*
774 * Check for execute permission to file based on current credentials.
775 */
776 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
777 if (error)
778 return (error);
779
780 /*
781 * Check number of open-for-writes on the file and deny execution
782 * if there are any.
783 */
784 if (vp->v_writecount)
785 return (ETXTBSY);
786
787 /*
788 * Call filesystem specific open routine (which does nothing in the
789 * general case).
790 */
791 error = VOP_OPEN(vp, FREAD, p->p_ucred, p);
792 if (error)
793 return (error);
794
795 return (0);
796}
797
798/*
799 * Exec handler registration
800 */
801int
802exec_register(execsw_arg)
803 const struct execsw *execsw_arg;
804{
805 const struct execsw **es, **xs, **newexecsw;
806 int count = 2; /* New slot and trailing NULL */
807
808 if (execsw)
809 for (es = execsw; *es; es++)
810 count++;
811 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
812 if (newexecsw == NULL)
813 return ENOMEM;
814 xs = newexecsw;
815 if (execsw)
816 for (es = execsw; *es; es++)
817 *xs++ = *es;
818 *xs++ = execsw_arg;
819 *xs = NULL;
820 if (execsw)
821 free(execsw, M_TEMP);
822 execsw = newexecsw;
823 return 0;
824}
825
826int
827exec_unregister(execsw_arg)
828 const struct execsw *execsw_arg;
829{
830 const struct execsw **es, **xs, **newexecsw;
831 int count = 1;
832
833 if (execsw == NULL)
834 panic("unregister with no handlers left?\n");
835
836 for (es = execsw; *es; es++) {
837 if (*es == execsw_arg)
838 break;
839 }
840 if (*es == NULL)
841 return ENOENT;
842 for (es = execsw; *es; es++)
843 if (*es != execsw_arg)
844 count++;
845 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
846 if (newexecsw == NULL)
847 return ENOMEM;
848 xs = newexecsw;
849 for (es = execsw; *es; es++)
850 if (*es != execsw_arg)
851 *xs++ = *es;
852 *xs = NULL;
853 if (execsw)
854 free(execsw, M_TEMP);
855 execsw = newexecsw;
856 return 0;
857}