xref: /openbsd-src/sys/kern/kern_exec.c (revision 8500990981f885cbe5e6a4958549cacc238b5ae6)
1 /*	$OpenBSD: kern_exec.c,v 1.82 2003/09/01 18:06:03 henning Exp $	*/
2 /*	$NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $	*/
3 
4 /*-
5  * Copyright (C) 1993, 1994 Christopher G. Demetriou
6  * Copyright (C) 1992 Wolfgang Solfrank.
7  * Copyright (C) 1992 TooLs GmbH.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/filedesc.h>
39 #include <sys/kernel.h>
40 #include <sys/proc.h>
41 #include <sys/mount.h>
42 #include <sys/malloc.h>
43 #include <sys/namei.h>
44 #include <sys/vnode.h>
45 #include <sys/file.h>
46 #include <sys/acct.h>
47 #include <sys/exec.h>
48 #include <sys/ktrace.h>
49 #include <sys/resourcevar.h>
50 #include <sys/wait.h>
51 #include <sys/mman.h>
52 #include <sys/signalvar.h>
53 #include <sys/stat.h>
54 #include <sys/conf.h>
55 #ifdef SYSVSHM
56 #include <sys/shm.h>
57 #endif
58 
59 #include <sys/syscallargs.h>
60 
61 #include <uvm/uvm_extern.h>
62 
63 #include <machine/cpu.h>
64 #include <machine/reg.h>
65 
66 #include <dev/rndvar.h>
67 
68 /*
69  * Map the shared signal code.
70  */
71 int exec_sigcode_map(struct proc *, struct emul *);
72 
73 /*
74  * stackgap_random specifies if the stackgap should have a random size added
75  * to it. Must be a n^2. If non-zero, the stack gap will be calculated as:
76  * (arc4random() * ALIGNBYTES) & (stackgap_random - 1) + STACKGAPLEN.
77  */
78 int stackgap_random = 64*1024;
79 
80 /*
81  * check exec:
82  * given an "executable" described in the exec package's namei info,
83  * see what we can do with it.
84  *
85  * ON ENTRY:
86  *	exec package with appropriate namei info
87  *	proc pointer of exec'ing proc
88  *	NO SELF-LOCKED VNODES
89  *
90  * ON EXIT:
91  *	error:	nothing held, etc.  exec header still allocated.
92  *	ok:	filled exec package, one locked vnode.
93  *
94  * EXEC SWITCH ENTRY:
95  * 	Locked vnode to check, exec package, proc.
96  *
97  * EXEC SWITCH EXIT:
98  *	ok:	return 0, filled exec package, one locked vnode.
99  *	error:	destructive:
100  *			everything deallocated execept exec header.
101  *		non-destructive:
102  *			error code, locked vnode, exec header unmodified
103  */
104 int
105 check_exec(p, epp)
106 	struct proc *p;
107 	struct exec_package *epp;
108 {
109 	int error, i;
110 	struct vnode *vp;
111 	struct nameidata *ndp;
112 	size_t resid;
113 
114 	ndp = epp->ep_ndp;
115 	ndp->ni_cnd.cn_nameiop = LOOKUP;
116 	ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME;
117 	/* first get the vnode */
118 	if ((error = namei(ndp)) != 0)
119 		return (error);
120 	epp->ep_vp = vp = ndp->ni_vp;
121 
122 	/* check for regular file */
123 	if (vp->v_type == VDIR) {
124 		error = EISDIR;
125 		goto bad1;
126 	}
127 	if (vp->v_type != VREG) {
128 		error = EACCES;
129 		goto bad1;
130 	}
131 
132 	/* get attributes */
133 	if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0)
134 		goto bad1;
135 
136 	/* Check mount point */
137 	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
138 		error = EACCES;
139 		goto bad1;
140 	}
141 
142 	if ((vp->v_mount->mnt_flag & MNT_NOSUID))
143 		epp->ep_vap->va_mode &= ~(VSUID | VSGID);
144 
145 	/* check access.  for root we have to see if any exec bit on */
146 	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
147 		goto bad1;
148 	if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) {
149 		error = EACCES;
150 		goto bad1;
151 	}
152 
153 	/* try to open it */
154 	if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0)
155 		goto bad1;
156 
157 	/* unlock vp, we need it unlocked from here */
158 	VOP_UNLOCK(vp, 0, p);
159 
160 	/* now we have the file, get the exec header */
161 	error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0,
162 	    UIO_SYSSPACE, 0, p->p_ucred, &resid, p);
163 	if (error)
164 		goto bad2;
165 	epp->ep_hdrvalid = epp->ep_hdrlen - resid;
166 
167 	/*
168 	 * set up the vmcmds for creation of the process
169 	 * address space
170 	 */
171 	error = ENOEXEC;
172 	for (i = 0; i < nexecs && error != 0; i++) {
173 		int newerror;
174 
175 		if (execsw[i].es_check == NULL)
176 			continue;
177 		newerror = (*execsw[i].es_check)(p, epp);
178 		if (!newerror && !(epp->ep_emul->e_flags & EMUL_ENABLED))
179 			newerror = ENOEXEC;
180 		/* make sure the first "interesting" error code is saved. */
181 		if (!newerror || error == ENOEXEC)
182 			error = newerror;
183 		if (epp->ep_flags & EXEC_DESTR && error != 0)
184 			return (error);
185 	}
186 	if (!error) {
187 		/* check that entry point is sane */
188 		if (epp->ep_entry > VM_MAXUSER_ADDRESS) {
189 			error = ENOEXEC;
190 		}
191 
192 		/* check limits */
193 		if ((epp->ep_tsize > MAXTSIZ) ||
194 		    (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur))
195 			error = ENOMEM;
196 
197 		if (!error)
198 			return (0);
199 	}
200 
201 	/*
202 	 * free any vmspace-creation commands,
203 	 * and release their references
204 	 */
205 	kill_vmcmds(&epp->ep_vmcmds);
206 
207 bad2:
208 	/*
209 	 * close the vnode, free the pathname buf, and punt.
210 	 */
211 	vn_close(vp, FREAD, p->p_ucred, p);
212 	FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
213 	return (error);
214 
215 bad1:
216 	/*
217 	 * free the namei pathname buffer, and put the vnode
218 	 * (which we don't yet have open).
219 	 */
220 	FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
221 	vput(vp);
222 	return (error);
223 }
224 
225 /*
226  * exec system call
227  */
228 /* ARGSUSED */
229 int
230 sys_execve(p, v, retval)
231 	register struct proc *p;
232 	void *v;
233 	register_t *retval;
234 {
235 	struct sys_execve_args /* {
236 		syscallarg(const char *) path;
237 		syscallarg(char *const *) argp;
238 		syscallarg(char *const *) envp;
239 	} */ *uap = v;
240 	int error;
241 	struct exec_package pack;
242 	struct nameidata nid;
243 	struct vattr attr;
244 	struct ucred *cred = p->p_ucred;
245 	char *argp;
246 	char * const *cpp, *dp, *sp;
247 	long argc, envc;
248 	size_t len, sgap;
249 #ifdef MACHINE_STACK_GROWS_UP
250 	size_t slen;
251 #endif
252 	char *stack;
253 	struct ps_strings arginfo;
254 	struct vmspace *vm = p->p_vmspace;
255 	char **tmpfap;
256 	extern struct emul emul_native;
257 
258 	/*
259 	 * Cheap solution to complicated problems.
260 	 * Mark this process as "leave me alone, I'm execing".
261 	 */
262 	p->p_flag |= P_INEXEC;
263 
264 	/* init the namei data to point the file user's program name */
265 	NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
266 
267 	/*
268 	 * initialize the fields of the exec package.
269 	 */
270 	pack.ep_name = (char *)SCARG(uap, path);
271 	pack.ep_hdr = malloc(exec_maxhdrsz, M_EXEC, M_WAITOK);
272 	pack.ep_hdrlen = exec_maxhdrsz;
273 	pack.ep_hdrvalid = 0;
274 	pack.ep_ndp = &nid;
275 	pack.ep_emul_arg = NULL;
276 	VMCMDSET_INIT(&pack.ep_vmcmds);
277 	pack.ep_vap = &attr;
278 	pack.ep_emul = &emul_native;
279 	pack.ep_flags = 0;
280 
281 	/* see if we can run it. */
282 	if ((error = check_exec(p, &pack)) != 0) {
283 		goto freehdr;
284 	}
285 
286 	/* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */
287 
288 	/* allocate an argument buffer */
289 	argp = (char *) uvm_km_valloc_wait(exec_map, NCARGS);
290 #ifdef DIAGNOSTIC
291 	if (argp == NULL)
292 		panic("execve: argp == NULL");
293 #endif
294 	dp = argp;
295 	argc = 0;
296 
297 	/* copy the fake args list, if there's one, freeing it as we go */
298 	if (pack.ep_flags & EXEC_HASARGL) {
299 		tmpfap = pack.ep_fa;
300 		while (*tmpfap != NULL) {
301 			char *cp;
302 
303 			cp = *tmpfap;
304 			while (*cp)
305 				*dp++ = *cp++;
306 			dp++;
307 
308 			free(*tmpfap, M_EXEC);
309 			tmpfap++; argc++;
310 		}
311 		FREE(pack.ep_fa, M_EXEC);
312 		pack.ep_flags &= ~EXEC_HASARGL;
313 	}
314 
315 	/* Now get argv & environment */
316 	if (!(cpp = SCARG(uap, argp))) {
317 		error = EFAULT;
318 		goto bad;
319 	}
320 
321 	if (pack.ep_flags & EXEC_SKIPARG)
322 		cpp++;
323 
324 	while (1) {
325 		len = argp + ARG_MAX - dp;
326 		if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
327 			goto bad;
328 		if (!sp)
329 			break;
330 		if ((error = copyinstr(sp, dp, len, &len)) != 0) {
331 			if (error == ENAMETOOLONG)
332 				error = E2BIG;
333 			goto bad;
334 		}
335 		dp += len;
336 		cpp++;
337 		argc++;
338 	}
339 
340 	envc = 0;
341 	/* environment does not need to be there */
342 	if ((cpp = SCARG(uap, envp)) != NULL ) {
343 		while (1) {
344 			len = argp + ARG_MAX - dp;
345 			if ((error = copyin(cpp, &sp, sizeof(sp))) != 0)
346 				goto bad;
347 			if (!sp)
348 				break;
349 			if ((error = copyinstr(sp, dp, len, &len)) != 0) {
350 				if (error == ENAMETOOLONG)
351 					error = E2BIG;
352 				goto bad;
353 			}
354 			dp += len;
355 			cpp++;
356 			envc++;
357 		}
358 	}
359 
360 	dp = (char *)ALIGN(dp);
361 
362 	sgap = STACKGAPLEN;
363 	if (stackgap_random != 0)
364 		sgap += (arc4random() * ALIGNBYTES) & (stackgap_random - 1);
365 	/* Now check if args & environ fit into new stack */
366 	len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) +
367 	    sizeof(long) + dp + sgap + sizeof(struct ps_strings)) - argp;
368 
369 	len = ALIGN(len);	/* make the stack "safely" aligned */
370 
371 	if (len > pack.ep_ssize) { /* in effect, compare to initial limit */
372 		error = ENOMEM;
373 		goto bad;
374 	}
375 
376 	/* adjust "active stack depth" for process VSZ */
377 	pack.ep_ssize = len;	/* maybe should go elsewhere, but... */
378 
379 	/*
380 	 * Prepare vmspace for remapping. Note that uvmspace_exec can replace
381 	 * p_vmspace!
382 	 */
383 	uvmspace_exec(p, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
384 
385 	vm = p->p_vmspace;
386 	/* Now map address space */
387 	vm->vm_taddr = (char *)pack.ep_taddr;
388 	vm->vm_tsize = btoc(pack.ep_tsize);
389 	vm->vm_daddr = (char *)pack.ep_daddr;
390 	vm->vm_dsize = btoc(pack.ep_dsize);
391 	vm->vm_ssize = btoc(pack.ep_ssize);
392 	vm->vm_maxsaddr = (char *)pack.ep_maxsaddr;
393 
394 	/* create the new process's VM space by running the vmcmds */
395 #ifdef DIAGNOSTIC
396 	if (pack.ep_vmcmds.evs_used == 0)
397 		panic("execve: no vmcmds");
398 #endif
399 	error = exec_process_vmcmds(p, &pack);
400 
401 	/* if an error happened, deallocate and punt */
402 	if (error)
403 		goto exec_abort;
404 
405 	/* remember information about the process */
406 	arginfo.ps_nargvstr = argc;
407 	arginfo.ps_nenvstr = envc;
408 
409 #ifdef MACHINE_STACK_GROWS_UP
410 	stack = (char *)USRSTACK + sizeof(arginfo);
411 	slen = len - sizeof(arginfo);
412 #else
413 	stack = (char *)(USRSTACK - len);
414 #endif
415 	/* Now copy argc, args & environ to new stack */
416 	if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp))
417 		goto exec_abort;
418 
419 	/* copy out the process's ps_strings structure */
420 	if (copyout(&arginfo, (char *)PS_STRINGS, sizeof(arginfo)))
421 		goto exec_abort;
422 
423 	stopprofclock(p);	/* stop profiling */
424 	fdcloseexec(p);		/* handle close on exec */
425 	execsigs(p);		/* reset catched signals */
426 
427 	/* set command name & other accounting info */
428 	len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN);
429 	bcopy(nid.ni_cnd.cn_nameptr, p->p_comm, len);
430 	p->p_comm[len] = 0;
431 	p->p_acflag &= ~AFORK;
432 
433 	/* record proc's vnode, for use by procfs and others */
434 	if (p->p_textvp)
435 		vrele(p->p_textvp);
436 	VREF(pack.ep_vp);
437 	p->p_textvp = pack.ep_vp;
438 
439 	p->p_flag |= P_EXEC;
440 	if (p->p_flag & P_PPWAIT) {
441 		p->p_flag &= ~P_PPWAIT;
442 		wakeup((caddr_t)p->p_pptr);
443 	}
444 
445 	/*
446 	 * If process does execve() while it has a mismatched real,
447 	 * effective, or saved uid/gid, we set P_SUGIDEXEC.
448 	 */
449 	if (p->p_ucred->cr_uid != p->p_cred->p_ruid ||
450 	    p->p_ucred->cr_uid != p->p_cred->p_svuid ||
451 	    p->p_ucred->cr_gid != p->p_cred->p_rgid ||
452 	    p->p_ucred->cr_gid != p->p_cred->p_svgid)
453 		p->p_flag |= P_SUGIDEXEC;
454 	else
455 		p->p_flag &= ~P_SUGIDEXEC;
456 
457 	/*
458 	 * deal with set[ug]id.
459 	 * MNT_NOEXEC has already been used to disable s[ug]id.
460 	 */
461 	if ((attr.va_mode & (VSUID | VSGID)) && proc_cansugid(p)) {
462 		int i;
463 
464 		p->p_flag |= P_SUGID;
465 		p->p_flag |= P_SUGIDEXEC;
466 
467 #ifdef KTRACE
468 		/*
469 		 * If process is being ktraced, turn off - unless
470 		 * root set it.
471 		 */
472 		if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) {
473 			p->p_traceflag = 0;
474 			ktrsettracevnode(p, NULL);
475 		}
476 #endif
477 		p->p_ucred = crcopy(cred);
478 		if (attr.va_mode & VSUID)
479 			p->p_ucred->cr_uid = attr.va_uid;
480 		if (attr.va_mode & VSGID)
481 			p->p_ucred->cr_gid = attr.va_gid;
482 
483 		/*
484 		 * For set[ug]id processes, a few caveats apply to
485 		 * stdin, stdout, and stderr.
486 		 */
487 		for (i = 0; i < 3; i++) {
488 			struct file *fp = NULL;
489 
490 			/*
491 			 * NOTE - This will never return NULL because of
492 			 * unmature fds. The file descriptor table is not
493 			 * shared because we're suid.
494 			 */
495 			fp = fd_getfile(p->p_fd, i);
496 #ifdef PROCFS
497 			/*
498 			 * Close descriptors that are writing to procfs.
499 			 */
500 			if (fp && fp->f_type == DTYPE_VNODE &&
501 			    ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS &&
502 			    (fp->f_flag & FWRITE)) {
503 				fdrelease(p, i);
504 				fp = NULL;
505 			}
506 #endif
507 
508 			/*
509 			 * Ensure that stdin, stdout, and stderr are already
510 			 * allocated.  We do not want userland to accidentally
511 			 * allocate descriptors in this range which has implied
512 			 * meaning to libc.
513 			 */
514 			if (fp == NULL) {
515 				short flags = FREAD | (i == 0 ? 0 : FWRITE);
516 				struct vnode *vp;
517 				int indx;
518 
519 				if ((error = falloc(p, &fp, &indx)) != 0)
520 					goto exec_abort;
521 #ifdef DIAGNOSTIC
522 				if (indx != i)
523 					panic("sys_execve: falloc indx != i");
524 #endif
525 				if ((error = cdevvp(getnulldev(), &vp)) != 0) {
526 					fdremove(p->p_fd, indx);
527 					closef(fp, p);
528 					goto exec_abort;
529 				}
530 				if ((error = VOP_OPEN(vp, flags, p->p_ucred, p)) != 0) {
531 					fdremove(p->p_fd, indx);
532 					closef(fp, p);
533 					vrele(vp);
534 					goto exec_abort;
535 				}
536 				if (flags & FWRITE)
537 					vp->v_writecount++;
538 				fp->f_flag = flags;
539 				fp->f_type = DTYPE_VNODE;
540 				fp->f_ops = &vnops;
541 				fp->f_data = (caddr_t)vp;
542 				FILE_SET_MATURE(fp);
543 			}
544 		}
545 	} else
546 		p->p_flag &= ~P_SUGID;
547 	p->p_cred->p_svuid = p->p_ucred->cr_uid;
548 	p->p_cred->p_svgid = p->p_ucred->cr_gid;
549 
550 	if (p->p_flag & P_SUGIDEXEC) {
551 		int i, s = splclock();
552 
553 		timeout_del(&p->p_realit_to);
554 		timerclear(&p->p_realtimer.it_interval);
555 		timerclear(&p->p_realtimer.it_value);
556 		for (i = 0; i < sizeof(p->p_stats->p_timer) /
557 		    sizeof(p->p_stats->p_timer[0]); i++) {
558 			timerclear(&p->p_stats->p_timer[i].it_interval);
559 			timerclear(&p->p_stats->p_timer[i].it_value);
560 		}
561 		splx(s);
562 	}
563 
564 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
565 
566 	FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
567 	vn_close(pack.ep_vp, FREAD, cred, p);
568 
569 	/*
570 	 * notify others that we exec'd
571 	 */
572 	KNOTE(&p->p_klist, NOTE_EXEC);
573 
574 	/* setup new registers and do misc. setup. */
575 	if (pack.ep_emul->e_fixup != NULL) {
576 		if ((*pack.ep_emul->e_fixup)(p, &pack) != 0)
577 			goto free_pack_abort;
578 	}
579 #ifdef MACHINE_STACK_GROWS_UP
580 	(*pack.ep_emul->e_setregs)(p, &pack, (u_long)stack + slen, retval);
581 #else
582 	(*pack.ep_emul->e_setregs)(p, &pack, (u_long)stack, retval);
583 #endif
584 
585 	/* map the process's signal trampoline code */
586 	if (exec_sigcode_map(p, pack.ep_emul))
587 		goto exec_abort;
588 
589 	if (p->p_flag & P_TRACED)
590 		psignal(p, SIGTRAP);
591 
592 	free(pack.ep_hdr, M_EXEC);
593 
594 	/*
595 	 * Call emulation specific exec hook. This can setup per-process
596 	 * p->p_emuldata or do any other per-process stuff an emulation needs.
597 	 *
598 	 * If we are executing process of different emulation than the
599 	 * original forked process, call e_proc_exit() of the old emulation
600 	 * first, then e_proc_exec() of new emulation. If the emulation is
601 	 * same, the exec hook code should deallocate any old emulation
602 	 * resources held previously by this process.
603 	 */
604 	if (p->p_emul && p->p_emul->e_proc_exit &&
605 	    p->p_emul != pack.ep_emul)
606 		(*p->p_emul->e_proc_exit)(p);
607 
608 	/*
609 	 * Call exec hook. Emulation code may NOT store reference to anything
610 	 * from &pack.
611 	 */
612 	if (pack.ep_emul->e_proc_exec)
613 		(*pack.ep_emul->e_proc_exec)(p, &pack);
614 
615 	/* update p_emul, the old value is no longer needed */
616 	p->p_emul = pack.ep_emul;
617 
618 #ifdef KTRACE
619 	if (KTRPOINT(p, KTR_EMUL))
620 		ktremul(p, p->p_emul->e_name);
621 #endif
622 	p->p_flag &= ~P_INEXEC;
623 	return (0);
624 
625 bad:
626 	/* free the vmspace-creation commands, and release their references */
627 	kill_vmcmds(&pack.ep_vmcmds);
628 	/* kill any opened file descriptor, if necessary */
629 	if (pack.ep_flags & EXEC_HASFD) {
630 		pack.ep_flags &= ~EXEC_HASFD;
631 		(void) fdrelease(p, pack.ep_fd);
632 	}
633 	/* close and put the exec'd file */
634 	vn_close(pack.ep_vp, FREAD, cred, p);
635 	FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
636 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
637 
638 freehdr:
639 	free(pack.ep_hdr, M_EXEC);
640 	p->p_flag &= ~P_INEXEC;
641 	return (error);
642 
643 exec_abort:
644 	/*
645 	 * the old process doesn't exist anymore.  exit gracefully.
646 	 * get rid of the (new) address space we have created, if any, get rid
647 	 * of our namei data and vnode, and exit noting failure
648 	 */
649 	uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS,
650 		VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS);
651 	if (pack.ep_emul_arg)
652 		FREE(pack.ep_emul_arg, M_TEMP);
653 	FREE(nid.ni_cnd.cn_pnbuf, M_NAMEI);
654 	vn_close(pack.ep_vp, FREAD, cred, p);
655 	uvm_km_free_wakeup(exec_map, (vaddr_t) argp, NCARGS);
656 
657 free_pack_abort:
658 	free(pack.ep_hdr, M_EXEC);
659 	exit1(p, W_EXITCODE(0, SIGABRT));
660 
661 	/* NOTREACHED */
662 	p->p_flag &= ~P_INEXEC;
663 	return (0);
664 }
665 
666 
667 void *
668 copyargs(pack, arginfo, stack, argp)
669 	struct exec_package *pack;
670 	struct ps_strings *arginfo;
671 	void *stack;
672 	void *argp;
673 {
674 	char **cpp = stack;
675 	char *dp, *sp;
676 	size_t len;
677 	void *nullp = NULL;
678 	long argc = arginfo->ps_nargvstr;
679 	int envc = arginfo->ps_nenvstr;
680 
681 	if (copyout(&argc, cpp++, sizeof(argc)))
682 		return (NULL);
683 
684 	dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen);
685 	sp = argp;
686 
687 	/* XXX don't copy them out, remap them! */
688 	arginfo->ps_argvstr = cpp; /* remember location of argv for later */
689 
690 	for (; --argc >= 0; sp += len, dp += len)
691 		if (copyout(&dp, cpp++, sizeof(dp)) ||
692 		    copyoutstr(sp, dp, ARG_MAX, &len))
693 			return (NULL);
694 
695 	if (copyout(&nullp, cpp++, sizeof(nullp)))
696 		return (NULL);
697 
698 	arginfo->ps_envstr = cpp; /* remember location of envp for later */
699 
700 	for (; --envc >= 0; sp += len, dp += len)
701 		if (copyout(&dp, cpp++, sizeof(dp)) ||
702 		    copyoutstr(sp, dp, ARG_MAX, &len))
703 			return (NULL);
704 
705 	if (copyout(&nullp, cpp++, sizeof(nullp)))
706 		return (NULL);
707 
708 	return (cpp);
709 }
710 
711 int
712 exec_sigcode_map(struct proc *p, struct emul *e)
713 {
714 	vsize_t sz;
715 
716 	sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode;
717 
718 	/*
719 	 * If we don't have a sigobject for this emulation, create one.
720 	 *
721 	 * sigobject is an anonymous memory object (just like SYSV shared
722 	 * memory) that we keep a permanent reference to and that we map
723 	 * in all processes that need this sigcode. The creation is simple,
724 	 * we create an object, add a permanent reference to it, map it in
725 	 * kernel space, copy out the sigcode to it and unmap it.
726 	 * Then we map it with PROT_READ|PROT_EXEC into the process just
727 	 * the way sys_mmap would map it.
728 	 */
729 	if (e->e_sigobject == NULL) {
730 		vaddr_t va;
731 		int r;
732 
733 		e->e_sigobject = uao_create(sz, 0);
734 		uao_reference(e->e_sigobject);	/* permanent reference */
735 
736 		va = vm_map_min(kernel_map);	/* hint */
737 		if ((r = uvm_map(kernel_map, &va, round_page(sz), e->e_sigobject,
738 		    0, 0, UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW,
739 		    UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) {
740 			printf("kernel mapping failed %d\n", r);
741 			return (ENOMEM);
742 		}
743 		memcpy((void *)va, e->e_sigcode, sz);
744 		uvm_unmap(kernel_map, va, va + round_page(sz));
745 	}
746 
747 	/* Just a hint to uvm_mmap where to put it. */
748 	p->p_sigcode = uvm_map_hint(p, VM_PROT_READ|VM_PROT_EXECUTE);
749 	uao_reference(e->e_sigobject);
750 	if (uvm_map(&p->p_vmspace->vm_map, &p->p_sigcode, round_page(sz),
751 	    e->e_sigobject, 0, 0, UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX,
752 	    UVM_INH_SHARE, UVM_ADV_RANDOM, 0))) {
753 		printf("user mapping failed\n");
754 		return (ENOMEM);
755 	}
756 
757 	return (0);
758 }
759