Fix a bug in signal translation introduced in last revision. This effects
[dragonfly.git] / sys / kern / kern_exec.c
CommitLineData
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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 $
2bd9d75c 27 * $DragonFly: src/sys/kern/kern_exec.c,v 1.14 2003/11/12 01:00:33 daver Exp $
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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>
2bd9d75c 41#include <sys/kern_syscall.h>
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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
402ed7e1 70static register_t *exec_copyout_strings (struct image_params *);
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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
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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
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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
984263bc 115int
2bd9d75c 116kern_execve(struct nameidata *ndp, struct image_args *args)
984263bc 117{
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118 struct thread *td = curthread;
119 struct proc *p = td->td_proc;
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120 register_t *stack_base;
121 int error, len, i;
122 struct image_params image_params, *imgp;
123 struct vattr attr;
402ed7e1 124 int (*img_first) (struct image_params *);
984263bc 125
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DRJ
126 if (debug_execve_args) {
127 printf("%s()\n", __func__);
128 print_execve_args(args);
129 }
130
dadab5e9 131 KKASSERT(p);
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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;
2bd9d75c 147 imgp->args = args;
984263bc 148 imgp->attr = &attr;
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149 imgp->entry_addr = 0;
150 imgp->vmspace_destroyed = 0;
151 imgp->interpreted = 0;
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152 imgp->auxargs = NULL;
153 imgp->vp = NULL;
154 imgp->firstpage = NULL;
155 imgp->ps_strings = 0;
156
157 /*
158 * Allocate temporary demand zeroed space for argument and
159 * environment strings
160 */
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DRJ
161 imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
162 if (imgp->image_header == NULL) {
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163 error = ENOMEM;
164 goto exec_fail;
165 }
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DRJ
166
167interpret:
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168
169 /*
170 * Translate the file name. namei() returns a vnode pointer
171 * in ni_vp amoung other things.
172 */
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173 error = namei(ndp);
174 if (error) {
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DRJ
175 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
176 PAGE_SIZE);
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177 goto exec_fail;
178 }
179
180 imgp->vp = ndp->ni_vp;
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181
182 /*
183 * Check file permissions (also 'opens' file)
184 */
185 error = exec_check_permissions(imgp);
186 if (error) {
dadab5e9 187 VOP_UNLOCK(imgp->vp, 0, td);
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188 goto exec_fail_dealloc;
189 }
190
191 error = exec_map_first_page(imgp);
dadab5e9 192 VOP_UNLOCK(imgp->vp, 0, td);
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193 if (error)
194 goto exec_fail_dealloc;
195
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DRJ
196 if (debug_execve_args && imgp->interpreted) {
197 printf(" target is interpreted -- recursive pass\n");
198 printf(" interpreter: %s\n", imgp->interpreter_name);
199 print_execve_args(args);
200 }
201
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202 /*
203 * If the current process has a special image activator it
204 * wants to try first, call it. For example, emulating shell
205 * scripts differently.
206 */
207 error = -1;
208 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL)
209 error = img_first(imgp);
210
211 /*
212 * Loop through the list of image activators, calling each one.
213 * An activator returns -1 if there is no match, 0 on success,
214 * and an error otherwise.
215 */
216 for (i = 0; error == -1 && execsw[i]; ++i) {
217 if (execsw[i]->ex_imgact == NULL ||
218 execsw[i]->ex_imgact == img_first) {
219 continue;
220 }
221 error = (*execsw[i]->ex_imgact)(imgp);
222 }
223
224 if (error) {
225 if (error == -1)
226 error = ENOEXEC;
227 goto exec_fail_dealloc;
228 }
229
230 /*
231 * Special interpreter operation, cleanup and loop up to try to
232 * activate the interpreter.
233 */
234 if (imgp->interpreted) {
235 exec_unmap_first_page(imgp);
236 /* free name buffer and old vnode */
237 NDFREE(ndp, NDF_ONLY_PNBUF);
238 vrele(ndp->ni_vp);
239 /* set new name to that of the interpreter */
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240 NDINIT(ndp, NAMEI_LOOKUP,
241 CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
dadab5e9 242 UIO_SYSSPACE, imgp->interpreter_name, td);
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243 goto interpret;
244 }
245
246 /*
247 * Copy out strings (args and env) and initialize stack base
248 */
249 stack_base = exec_copyout_strings(imgp);
250 p->p_vmspace->vm_minsaddr = (char *)stack_base;
251
252 /*
253 * If custom stack fixup routine present for this process
254 * let it do the stack setup.
255 * Else stuff argument count as first item on stack
256 */
257 if (p->p_sysent->sv_fixup)
258 (*p->p_sysent->sv_fixup)(&stack_base, imgp);
259 else
2bd9d75c 260 suword(--stack_base, imgp->args->argc);
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261
262 /*
263 * For security and other reasons, the file descriptor table cannot
264 * be shared after an exec.
265 */
266 if (p->p_fd->fd_refcnt > 1) {
267 struct filedesc *tmp;
268
269 tmp = fdcopy(p);
270 fdfree(p);
271 p->p_fd = tmp;
272 }
273
274 /*
275 * For security and other reasons, signal handlers cannot
276 * be shared after an exec. The new proces gets a copy of the old
277 * handlers. In execsigs(), the new process will have its signals
278 * reset.
279 */
280 if (p->p_procsig->ps_refcnt > 1) {
281 struct procsig *newprocsig;
282
283 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig),
284 M_SUBPROC, M_WAITOK);
285 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig));
286 p->p_procsig->ps_refcnt--;
287 p->p_procsig = newprocsig;
288 p->p_procsig->ps_refcnt = 1;
289 if (p->p_sigacts == &p->p_addr->u_sigacts)
290 panic("shared procsig but private sigacts?");
291
292 p->p_addr->u_sigacts = *p->p_sigacts;
293 p->p_sigacts = &p->p_addr->u_sigacts;
294 }
295
296 /* Stop profiling */
297 stopprofclock(p);
298
299 /* close files on exec */
300 fdcloseexec(p);
301
302 /* reset caught signals */
303 execsigs(p);
304
305 /* name this process - nameiexec(p, ndp) */
306 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
307 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
308 p->p_comm[len] = 0;
309
310 /*
311 * mark as execed, wakeup the process that vforked (if any) and tell
312 * it that it now has its own resources back
313 */
314 p->p_flag |= P_EXEC;
315 if (p->p_pptr && (p->p_flag & P_PPWAIT)) {
316 p->p_flag &= ~P_PPWAIT;
317 wakeup((caddr_t)p->p_pptr);
318 }
319
320 /*
321 * Implement image setuid/setgid.
322 *
323 * Don't honor setuid/setgid if the filesystem prohibits it or if
324 * the process is being traced.
325 */
326 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) ||
327 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) &&
328 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 &&
329 (p->p_flag & P_TRACED) == 0) {
330 /*
331 * Turn off syscall tracing for set-id programs, except for
332 * root. Record any set-id flags first to make sure that
333 * we do not regain any tracing during a possible block.
334 */
41c20dac 335 setsugid();
dadab5e9 336 if (p->p_tracep && suser(td)) {
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337 struct vnode *vtmp;
338
339 if ((vtmp = p->p_tracep) != NULL) {
340 p->p_tracep = NULL;
341 p->p_traceflag = 0;
342 vrele(vtmp);
343 }
344 }
345 /* Close any file descriptors 0..2 that reference procfs */
346 setugidsafety(p);
347 /* Make sure file descriptors 0..2 are in use. */
348 error = fdcheckstd(p);
349 if (error != 0)
350 goto exec_fail_dealloc;
351 /*
352 * Set the new credentials.
353 */
e9a372eb 354 cratom(&p->p_ucred);
984263bc 355 if (attr.va_mode & VSUID)
41c20dac 356 change_euid(attr.va_uid);
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357 if (attr.va_mode & VSGID)
358 p->p_ucred->cr_gid = attr.va_gid;
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359
360 /*
361 * Clear local varsym variables
362 */
363 varsymset_clean(&p->p_varsymset);
984263bc 364 } else {
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MD
365 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid &&
366 p->p_ucred->cr_gid == p->p_ucred->cr_rgid)
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367 p->p_flag &= ~P_SUGID;
368 }
369
370 /*
371 * Implement correct POSIX saved-id behavior.
372 */
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MD
373 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid ||
374 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) {
375 cratom(&p->p_ucred);
376 p->p_ucred->cr_svuid = p->p_ucred->cr_uid;
377 p->p_ucred->cr_svgid = p->p_ucred->cr_gid;
378 }
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379
380 /*
381 * Store the vp for use in procfs
382 */
383 if (p->p_textvp) /* release old reference */
384 vrele(p->p_textvp);
385 VREF(ndp->ni_vp);
386 p->p_textvp = ndp->ni_vp;
387
388 /*
389 * Notify others that we exec'd, and clear the P_INEXEC flag
390 * as we're now a bona fide freshly-execed process.
391 */
392 KNOTE(&p->p_klist, NOTE_EXEC);
393 p->p_flag &= ~P_INEXEC;
394
395 /*
396 * If tracing the process, trap to debugger so breakpoints
397 * can be set before the program executes.
398 */
399 STOPEVENT(p, S_EXEC, 0);
400
401 if (p->p_flag & P_TRACED)
402 psignal(p, SIGTRAP);
403
404 /* clear "fork but no exec" flag, as we _are_ execing */
405 p->p_acflag &= ~AFORK;
406
407 /* Set values passed into the program in registers. */
408 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base,
409 imgp->ps_strings);
410
411 /* Free any previous argument cache */
412 if (p->p_args && --p->p_args->ar_ref == 0)
413 FREE(p->p_args, M_PARGS);
414 p->p_args = NULL;
415
416 /* Cache arguments if they fit inside our allowance */
2bd9d75c 417 i = imgp->args->begin_envv - imgp->args->begin_argv;
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MD
418 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
419 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i,
420 M_PARGS, M_WAITOK);
421 p->p_args->ar_ref = 1;
422 p->p_args->ar_length = i;
2bd9d75c 423 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i);
984263bc
MD
424 }
425
426exec_fail_dealloc:
427
428 /*
429 * free various allocated resources
430 */
431 if (imgp->firstpage)
432 exec_unmap_first_page(imgp);
433
2bd9d75c
DRJ
434 if (imgp->image_header != NULL)
435 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
436 PAGE_SIZE);
984263bc
MD
437
438 if (imgp->vp) {
439 NDFREE(ndp, NDF_ONLY_PNBUF);
440 vrele(imgp->vp);
441 }
442
443 if (error == 0)
444 return (0);
445
446exec_fail:
447 /* we're done here, clear P_INEXEC */
448 p->p_flag &= ~P_INEXEC;
449 if (imgp->vmspace_destroyed) {
450 /* sorry, no more process anymore. exit gracefully */
41c20dac 451 exit1(W_EXITCODE(0, SIGABRT));
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452 /* NOT REACHED */
453 return(0);
454 } else {
455 return(error);
456 }
457}
458
2bd9d75c
DRJ
459/*
460 * execve() system call.
461 */
462int
463execve(struct execve_args *uap)
464{
465 struct thread *td = curthread;
466 struct nameidata nd;
467 struct image_args args;
468 int error;
469
470 NDINIT(&nd, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME,
471 UIO_USERSPACE, uap->fname, td);
472
473 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE,
474 uap->argv, uap->envv);
475 if (error)
476 return (error);
477
478 error = kern_execve(&nd, &args);
479
480 exec_free_args(&args);
481
482 /*
483 * The syscall result is returned in registers to the new program.
484 * Linux will register %edx as an atexit function and we must be
485 * sure to set it to 0. XXX
486 */
487 if (error == 0)
488 uap->sysmsg_result64 = 0;
489
490 return (error);
491}
492
984263bc 493int
41c20dac 494exec_map_first_page(struct image_params *imgp)
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MD
495{
496 int s, rv, i;
497 int initial_pagein;
498 vm_page_t ma[VM_INITIAL_PAGEIN];
499 vm_object_t object;
500
501
502 if (imgp->firstpage) {
503 exec_unmap_first_page(imgp);
504 }
505
506 VOP_GETVOBJECT(imgp->vp, &object);
507 s = splvm();
508
509 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
510
511 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
512 initial_pagein = VM_INITIAL_PAGEIN;
513 if (initial_pagein > object->size)
514 initial_pagein = object->size;
515 for (i = 1; i < initial_pagein; i++) {
516 if ((ma[i] = vm_page_lookup(object, i)) != NULL) {
517 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy)
518 break;
519 if (ma[i]->valid)
520 break;
521 vm_page_busy(ma[i]);
522 } else {
523 ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL);
524 if (ma[i] == NULL)
525 break;
526 }
527 }
528 initial_pagein = i;
529
530 rv = vm_pager_get_pages(object, ma, initial_pagein, 0);
531 ma[0] = vm_page_lookup(object, 0);
532
533 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) {
534 if (ma[0]) {
535 vm_page_protect(ma[0], VM_PROT_NONE);
536 vm_page_free(ma[0]);
537 }
538 splx(s);
539 return EIO;
540 }
541 }
542
543 vm_page_wire(ma[0]);
544 vm_page_wakeup(ma[0]);
545 splx(s);
546
547 pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0]));
548 imgp->firstpage = ma[0];
549
550 return 0;
551}
552
553void
554exec_unmap_first_page(imgp)
555 struct image_params *imgp;
556{
557 if (imgp->firstpage) {
558 pmap_kremove((vm_offset_t) imgp->image_header);
559 vm_page_unwire(imgp->firstpage, 1);
560 imgp->firstpage = NULL;
561 }
562}
563
564/*
565 * Destroy old address space, and allocate a new stack
566 * The new stack is only SGROWSIZ large because it is grown
567 * automatically in trap.c.
568 */
569int
570exec_new_vmspace(imgp)
571 struct image_params *imgp;
572{
573 int error;
574 struct vmspace *vmspace = imgp->proc->p_vmspace;
575 vm_offset_t stack_addr = USRSTACK - maxssiz;
576 vm_map_t map = &vmspace->vm_map;
577
578 imgp->vmspace_destroyed = 1;
579
580 /*
581 * Prevent a pending AIO from modifying the new address space.
582 */
583 aio_proc_rundown(imgp->proc);
584
585 /*
586 * Blow away entire process VM, if address space not shared,
587 * otherwise, create a new VM space so that other threads are
588 * not disrupted
589 */
590 if (vmspace->vm_refcnt == 1) {
fef0fdf2 591 shmexit(vmspace);
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592 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS);
593 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS);
594 } else {
595 vmspace_exec(imgp->proc);
596 vmspace = imgp->proc->p_vmspace;
597 map = &vmspace->vm_map;
598 }
599
600 /* Allocate a new stack */
601 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz,
602 VM_PROT_ALL, VM_PROT_ALL, 0);
603 if (error)
604 return (error);
605
606 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the
607 * VM_STACK case, but they are still used to monitor the size of the
608 * process stack so we can check the stack rlimit.
609 */
610 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT;
611 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz;
612
613 return(0);
614}
615
616/*
617 * Copy out argument and environment strings from the old process
618 * address space into the temporary string buffer.
619 */
620int
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DRJ
621exec_copyin_args(struct image_args *args, char *fname,
622 enum exec_path_segflg segflg, char **argv, char **envv)
984263bc 623{
984263bc 624 char *argp, *envp;
2bd9d75c 625 int error = 0;
984263bc
MD
626 size_t length;
627
2bd9d75c
DRJ
628 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX);
629 if (args->buf == NULL)
630 return (ENOMEM);
631 args->begin_argv = args->buf;
632 args->endp = args->begin_argv;
633 args->space = ARG_MAX;
634 args->argc = 0;
635 args->envc = 0;
636
637 args->fname = args->buf + ARG_MAX;
638
984263bc 639 /*
2bd9d75c 640 * Copy the file name.
984263bc 641 */
2bd9d75c
DRJ
642 if (segflg == PATH_SYSSPACE) {
643 error = copystr(fname, args->fname, PATH_MAX, &length);
644 } else if (segflg == PATH_USERSPACE) {
645 error = copyinstr(fname, args->fname, PATH_MAX, &length);
646 }
984263bc 647
2bd9d75c
DRJ
648 /*
649 * extract argument strings
650 */
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MD
651
652 if (argv) {
653 argp = (caddr_t) (intptr_t) fuword(argv);
2bd9d75c
DRJ
654 /*
655 * First argument is a special case. If it is a null
656 * string, we must copy the file name into the string
657 * buffer as the first argument. This guarantees that
658 * the interpreter knows what file to open in the case
659 * that we exec an interpreted file.
660 */
661 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) {
662 if (argp == (caddr_t) -1) {
663 error = EFAULT;
664 goto cleanup;
665 }
666 error = copyinstr(argp, args->endp,
667 args->space, &length);
668 if (error == ENAMETOOLONG)
669 error = E2BIG;
670 if (error)
671 goto cleanup;
672 args->space -= length;
673 args->endp += length;
674 args->argc++;
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675 }
676 }
677
2bd9d75c 678 args->begin_envv = args->endp;
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679
680 /*
681 * extract environment strings
682 */
683
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684 if (envv) {
685 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) {
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686 if (envp == (caddr_t) -1) {
687 error = EFAULT;
688 goto cleanup;
984263bc 689 }
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690 error = copyinstr(envp, args->endp, args->space,
691 &length);
692 if (error == ENAMETOOLONG)
693 error = E2BIG;
694 if (error)
695 goto cleanup;
696 args->space -= length;
697 args->endp += length;
698 args->envc++;
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699 }
700 }
701
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702cleanup:
703 if (error)
704 exec_free_args(args);
705 return (error);
706}
707
708void
709exec_free_args(struct image_args *args)
710{
711 kmem_free_wakeup(exec_map, (vm_offset_t)args->buf, PATH_MAX + ARG_MAX);
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712}
713
714/*
715 * Copy strings out to the new process address space, constructing
716 * new arg and env vector tables. Return a pointer to the base
717 * so that it can be used as the initial stack pointer.
718 */
719register_t *
2bd9d75c 720exec_copyout_strings(struct image_params *imgp)
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721{
722 int argc, envc;
723 char **vectp;
724 char *stringp, *destp;
725 register_t *stack_base;
726 struct ps_strings *arginfo;
727 int szsigcode;
728
729 /*
730 * Calculate string base and vector table pointers.
731 * Also deal with signal trampoline code for this exec type.
732 */
733 arginfo = (struct ps_strings *)PS_STRINGS;
734 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode);
735 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE -
2bd9d75c 736 roundup((ARG_MAX - imgp->args->space), sizeof(char *));
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737
738 /*
739 * install sigcode
740 */
741 if (szsigcode)
742 copyout(imgp->proc->p_sysent->sv_sigcode,
2bd9d75c 743 ((caddr_t)arginfo - szsigcode), szsigcode);
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744
745 /*
746 * If we have a valid auxargs ptr, prepare some room
747 * on the stack.
748 */
749 if (imgp->auxargs)
750 /*
751 * The '+ 2' is for the null pointers at the end of each of the
752 * arg and env vector sets, and 'AT_COUNT*2' is room for the
753 * ELF Auxargs data.
754 */
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755 vectp = (char **)(destp - (imgp->args->argc +
756 imgp->args->envc + 2 + AT_COUNT*2) * sizeof(char*));
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757 else
758 /*
759 * The '+ 2' is for the null pointers at the end of each of the
760 * arg and env vector sets
761 */
762 vectp = (char **)
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763 (destp - (imgp->args->argc + imgp->args->envc + 2) *
764 sizeof(char*));
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765
766 /*
767 * vectp also becomes our initial stack base
768 */
769 stack_base = (register_t *)vectp;
770
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771 stringp = imgp->args->begin_argv;
772 argc = imgp->args->argc;
773 envc = imgp->args->envc;
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774
775 /*
776 * Copy out strings - arguments and environment.
777 */
2bd9d75c 778 copyout(stringp, destp, ARG_MAX - imgp->args->space);
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779
780 /*
781 * Fill in "ps_strings" struct for ps, w, etc.
782 */
783 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
784 suword(&arginfo->ps_nargvstr, argc);
785
786 /*
787 * Fill in argument portion of vector table.
788 */
789 for (; argc > 0; --argc) {
790 suword(vectp++, (long)(intptr_t)destp);
791 while (*stringp++ != 0)
792 destp++;
793 destp++;
794 }
795
796 /* a null vector table pointer seperates the argp's from the envp's */
797 suword(vectp++, 0);
798
799 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
800 suword(&arginfo->ps_nenvstr, envc);
801
802 /*
803 * Fill in environment portion of vector table.
804 */
805 for (; envc > 0; --envc) {
806 suword(vectp++, (long)(intptr_t)destp);
807 while (*stringp++ != 0)
808 destp++;
809 destp++;
810 }
811
812 /* end of vector table is a null pointer */
813 suword(vectp, 0);
814
815 return (stack_base);
816}
817
818/*
819 * Check permissions of file to execute.
820 * Return 0 for success or error code on failure.
821 */
822int
823exec_check_permissions(imgp)
824 struct image_params *imgp;
825{
826 struct proc *p = imgp->proc;
827 struct vnode *vp = imgp->vp;
828 struct vattr *attr = imgp->attr;
dadab5e9 829 struct thread *td = p->p_thread;
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830 int error;
831
832 /* Get file attributes */
3b568787 833 error = VOP_GETATTR(vp, attr, td);
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834 if (error)
835 return (error);
836
837 /*
838 * 1) Check if file execution is disabled for the filesystem that this
839 * file resides on.
840 * 2) Insure that at least one execute bit is on - otherwise root
841 * will always succeed, and we don't want to happen unless the
842 * file really is executable.
843 * 3) Insure that the file is a regular file.
844 */
845 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
846 ((attr->va_mode & 0111) == 0) ||
847 (attr->va_type != VREG)) {
848 return (EACCES);
849 }
850
851 /*
852 * Zero length files can't be exec'd
853 */
854 if (attr->va_size == 0)
855 return (ENOEXEC);
856
857 /*
858 * Check for execute permission to file based on current credentials.
859 */
dadab5e9 860 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td);
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861 if (error)
862 return (error);
863
864 /*
865 * Check number of open-for-writes on the file and deny execution
866 * if there are any.
867 */
868 if (vp->v_writecount)
869 return (ETXTBSY);
870
871 /*
872 * Call filesystem specific open routine (which does nothing in the
873 * general case).
874 */
dadab5e9 875 error = VOP_OPEN(vp, FREAD, p->p_ucred, td);
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876 if (error)
877 return (error);
878
879 return (0);
880}
881
882/*
883 * Exec handler registration
884 */
885int
886exec_register(execsw_arg)
887 const struct execsw *execsw_arg;
888{
889 const struct execsw **es, **xs, **newexecsw;
890 int count = 2; /* New slot and trailing NULL */
891
892 if (execsw)
893 for (es = execsw; *es; es++)
894 count++;
895 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
896 if (newexecsw == NULL)
897 return ENOMEM;
898 xs = newexecsw;
899 if (execsw)
900 for (es = execsw; *es; es++)
901 *xs++ = *es;
902 *xs++ = execsw_arg;
903 *xs = NULL;
904 if (execsw)
905 free(execsw, M_TEMP);
906 execsw = newexecsw;
907 return 0;
908}
909
910int
911exec_unregister(execsw_arg)
912 const struct execsw *execsw_arg;
913{
914 const struct execsw **es, **xs, **newexecsw;
915 int count = 1;
916
917 if (execsw == NULL)
918 panic("unregister with no handlers left?\n");
919
920 for (es = execsw; *es; es++) {
921 if (*es == execsw_arg)
922 break;
923 }
924 if (*es == NULL)
925 return ENOENT;
926 for (es = execsw; *es; es++)
927 if (*es != execsw_arg)
928 count++;
929 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK);
930 if (newexecsw == NULL)
931 return ENOMEM;
932 xs = newexecsw;
933 for (es = execsw; *es; es++)
934 if (*es != execsw_arg)
935 *xs++ = *es;
936 *xs = NULL;
937 if (execsw)
938 free(execsw, M_TEMP);
939 execsw = newexecsw;
940 return 0;
941}