1/*-
2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include "namespace.h"
31#include <sys/queue.h>
32#include <sys/wait.h>
33
34#include <errno.h>
35#include <fcntl.h>
36#include <sched.h>
37#include <spawn.h>
38#include <signal.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42#include "un-namespace.h"
43#include "libc_private.h"
44
45extern char **environ;
46
47struct __posix_spawnattr {
48	short			sa_flags;
49	pid_t			sa_pgroup;
50	struct sched_param	sa_schedparam;
51	int			sa_schedpolicy;
52	sigset_t		sa_sigdefault;
53	sigset_t		sa_sigmask;
54};
55
56struct __posix_spawn_file_actions {
57	STAILQ_HEAD(, __posix_spawn_file_actions_entry) fa_list;
58};
59
60typedef struct __posix_spawn_file_actions_entry {
61	STAILQ_ENTRY(__posix_spawn_file_actions_entry) fae_list;
62	enum { FAE_OPEN, FAE_DUP2, FAE_CLOSE } fae_action;
63
64	int fae_fildes;
65	union {
66		struct {
67			char *path;
68#define fae_path	fae_data.open.path
69			int oflag;
70#define fae_oflag	fae_data.open.oflag
71			mode_t mode;
72#define fae_mode	fae_data.open.mode
73		} open;
74		struct {
75			int newfildes;
76#define fae_newfildes	fae_data.dup2.newfildes
77		} dup2;
78	} fae_data;
79} posix_spawn_file_actions_entry_t;
80
81/*
82 * Spawn routines
83 */
84
85static int
86process_spawnattr(const posix_spawnattr_t sa)
87{
88	struct sigaction sigact = { .sa_flags = 0, .sa_handler = SIG_DFL };
89	int i;
90
91	/*
92	 * POSIX doesn't really describe in which order everything
93	 * should be set. We'll just set them in the order in which they
94	 * are mentioned.
95	 */
96
97	/* Set process group */
98	if (sa->sa_flags & POSIX_SPAWN_SETPGROUP) {
99		if (setpgid(0, sa->sa_pgroup) != 0)
100			return (errno);
101	}
102
103	/* Set scheduler policy */
104	if (sa->sa_flags & POSIX_SPAWN_SETSCHEDULER) {
105		if (sched_setscheduler(0, sa->sa_schedpolicy,
106		    &sa->sa_schedparam) != 0)
107			return (errno);
108	} else if (sa->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) {
109		if (sched_setparam(0, &sa->sa_schedparam) != 0)
110			return (errno);
111	}
112
113	/* Reset user ID's */
114	if (sa->sa_flags & POSIX_SPAWN_RESETIDS) {
115		if (setegid(getgid()) != 0)
116			return (errno);
117		if (seteuid(getuid()) != 0)
118			return (errno);
119	}
120
121	/*
122	 * Set signal masks/defaults.
123	 * Use unwrapped syscall, libthr is in undefined state after vfork().
124	 */
125	if (sa->sa_flags & POSIX_SPAWN_SETSIGMASK) {
126		__sys_sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
127	}
128
129	if (sa->sa_flags & POSIX_SPAWN_SETSIGDEF) {
130		for (i = 1; i <= _SIG_MAXSIG; i++) {
131			if (sigismember(&sa->sa_sigdefault, i))
132				if (__sys_sigaction(i, &sigact, NULL) != 0)
133					return (errno);
134		}
135	}
136
137	return (0);
138}
139
140static int
141process_file_actions_entry(posix_spawn_file_actions_entry_t *fae)
142{
143	int fd, saved_errno;
144
145	switch (fae->fae_action) {
146	case FAE_OPEN:
147		/* Perform an open(), make it use the right fd */
148		fd = _open(fae->fae_path, fae->fae_oflag, fae->fae_mode);
149		if (fd < 0)
150			return (errno);
151		if (fd != fae->fae_fildes) {
152			if (_dup2(fd, fae->fae_fildes) == -1) {
153				saved_errno = errno;
154				(void)_close(fd);
155				return (saved_errno);
156			}
157			if (_close(fd) != 0) {
158				if (errno == EBADF)
159					return (EBADF);
160			}
161		}
162		if (_fcntl(fae->fae_fildes, F_SETFD, 0) == -1)
163			return (errno);
164		break;
165	case FAE_DUP2:
166		/* Perform a dup2() */
167		if (_dup2(fae->fae_fildes, fae->fae_newfildes) == -1)
168			return (errno);
169		if (_fcntl(fae->fae_newfildes, F_SETFD, 0) == -1)
170			return (errno);
171		break;
172	case FAE_CLOSE:
173		/* Perform a close(), do not fail if already closed */
174		(void)_close(fae->fae_fildes);
175		break;
176	}
177	return (0);
178}
179
180static int
181process_file_actions(const posix_spawn_file_actions_t fa)
182{
183	posix_spawn_file_actions_entry_t *fae;
184	int error;
185
186	/* Replay all file descriptor modifications */
187	STAILQ_FOREACH(fae, &fa->fa_list, fae_list) {
188		error = process_file_actions_entry(fae);
189		if (error)
190			return (error);
191	}
192	return (0);
193}
194
195static int
196do_posix_spawn(pid_t *pid, const char *path,
197    const posix_spawn_file_actions_t *fa,
198    const posix_spawnattr_t *sa,
199    char * const argv[], char * const envp[], int use_env_path)
200{
201	pid_t p;
202	volatile int error = 0;
203
204	p = vfork();
205	switch (p) {
206	case -1:
207		return (errno);
208	case 0:
209		if (sa != NULL) {
210			error = process_spawnattr(*sa);
211			if (error)
212				_exit(127);
213		}
214		if (fa != NULL) {
215			error = process_file_actions(*fa);
216			if (error)
217				_exit(127);
218		}
219		if (use_env_path)
220			_execvpe(path, argv, envp != NULL ? envp : environ);
221		else
222			_execve(path, argv, envp != NULL ? envp : environ);
223		error = errno;
224		_exit(127);
225	default:
226		if (error != 0)
227			_waitpid(p, NULL, WNOHANG);
228		else if (pid != NULL)
229			*pid = p;
230		return (error);
231	}
232}
233
234int
235posix_spawn(pid_t *pid, const char *path,
236    const posix_spawn_file_actions_t *fa,
237    const posix_spawnattr_t *sa,
238    char * const argv[], char * const envp[])
239{
240	return do_posix_spawn(pid, path, fa, sa, argv, envp, 0);
241}
242
243int
244posix_spawnp(pid_t *pid, const char *path,
245    const posix_spawn_file_actions_t *fa,
246    const posix_spawnattr_t *sa,
247    char * const argv[], char * const envp[])
248{
249	return do_posix_spawn(pid, path, fa, sa, argv, envp, 1);
250}
251
252/*
253 * File descriptor actions
254 */
255
256int
257posix_spawn_file_actions_init(posix_spawn_file_actions_t *ret)
258{
259	posix_spawn_file_actions_t fa;
260
261	fa = malloc(sizeof(struct __posix_spawn_file_actions));
262	if (fa == NULL)
263		return (-1);
264
265	STAILQ_INIT(&fa->fa_list);
266	*ret = fa;
267	return (0);
268}
269
270int
271posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *fa)
272{
273	posix_spawn_file_actions_entry_t *fae;
274
275	while ((fae = STAILQ_FIRST(&(*fa)->fa_list)) != NULL) {
276		/* Remove file action entry from the queue */
277		STAILQ_REMOVE_HEAD(&(*fa)->fa_list, fae_list);
278
279		/* Deallocate file action entry */
280		if (fae->fae_action == FAE_OPEN)
281			free(fae->fae_path);
282		free(fae);
283	}
284
285	free(*fa);
286	return (0);
287}
288
289int
290posix_spawn_file_actions_addopen(posix_spawn_file_actions_t * __restrict fa,
291    int fildes, const char * __restrict path, int oflag, mode_t mode)
292{
293	posix_spawn_file_actions_entry_t *fae;
294	int error;
295
296	if (fildes < 0)
297		return (EBADF);
298
299	/* Allocate object */
300	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
301	if (fae == NULL)
302		return (errno);
303
304	/* Set values and store in queue */
305	fae->fae_action = FAE_OPEN;
306	fae->fae_path = strdup(path);
307	if (fae->fae_path == NULL) {
308		error = errno;
309		free(fae);
310		return (error);
311	}
312	fae->fae_fildes = fildes;
313	fae->fae_oflag = oflag;
314	fae->fae_mode = mode;
315
316	STAILQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
317	return (0);
318}
319
320int
321posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t *fa,
322    int fildes, int newfildes)
323{
324	posix_spawn_file_actions_entry_t *fae;
325
326	if (fildes < 0 || newfildes < 0)
327		return (EBADF);
328
329	/* Allocate object */
330	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
331	if (fae == NULL)
332		return (errno);
333
334	/* Set values and store in queue */
335	fae->fae_action = FAE_DUP2;
336	fae->fae_fildes = fildes;
337	fae->fae_newfildes = newfildes;
338
339	STAILQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
340	return (0);
341}
342
343int
344posix_spawn_file_actions_addclose(posix_spawn_file_actions_t *fa,
345    int fildes)
346{
347	posix_spawn_file_actions_entry_t *fae;
348
349	if (fildes < 0)
350		return (EBADF);
351
352	/* Allocate object */
353	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
354	if (fae == NULL)
355		return (errno);
356
357	/* Set values and store in queue */
358	fae->fae_action = FAE_CLOSE;
359	fae->fae_fildes = fildes;
360
361	STAILQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
362	return (0);
363}
364
365/*
366 * Spawn attributes
367 */
368
369int
370posix_spawnattr_init(posix_spawnattr_t *ret)
371{
372	posix_spawnattr_t sa;
373
374	sa = calloc(1, sizeof(struct __posix_spawnattr));
375	if (sa == NULL)
376		return (errno);
377
378	/* Set defaults as specified by POSIX, cleared above */
379	*ret = sa;
380	return (0);
381}
382
383int
384posix_spawnattr_destroy(posix_spawnattr_t *sa)
385{
386	free(*sa);
387	return (0);
388}
389
390int
391posix_spawnattr_getflags(const posix_spawnattr_t * __restrict sa,
392    short * __restrict flags)
393{
394	*flags = (*sa)->sa_flags;
395	return (0);
396}
397
398int
399posix_spawnattr_getpgroup(const posix_spawnattr_t * __restrict sa,
400    pid_t * __restrict pgroup)
401{
402	*pgroup = (*sa)->sa_pgroup;
403	return (0);
404}
405
406int
407posix_spawnattr_getschedparam(const posix_spawnattr_t * __restrict sa,
408    struct sched_param * __restrict schedparam)
409{
410	*schedparam = (*sa)->sa_schedparam;
411	return (0);
412}
413
414int
415posix_spawnattr_getschedpolicy(const posix_spawnattr_t * __restrict sa,
416    int * __restrict schedpolicy)
417{
418	*schedpolicy = (*sa)->sa_schedpolicy;
419	return (0);
420}
421
422int
423posix_spawnattr_getsigdefault(const posix_spawnattr_t * __restrict sa,
424    sigset_t * __restrict sigdefault)
425{
426	*sigdefault = (*sa)->sa_sigdefault;
427	return (0);
428}
429
430int
431posix_spawnattr_getsigmask(const posix_spawnattr_t * __restrict sa,
432    sigset_t * __restrict sigmask)
433{
434	*sigmask = (*sa)->sa_sigmask;
435	return (0);
436}
437
438int
439posix_spawnattr_setflags(posix_spawnattr_t *sa, short flags)
440{
441	(*sa)->sa_flags = flags;
442	return (0);
443}
444
445int
446posix_spawnattr_setpgroup(posix_spawnattr_t *sa, pid_t pgroup)
447{
448	(*sa)->sa_pgroup = pgroup;
449	return (0);
450}
451
452int
453posix_spawnattr_setschedparam(posix_spawnattr_t * __restrict sa,
454    const struct sched_param * __restrict schedparam)
455{
456	(*sa)->sa_schedparam = *schedparam;
457	return (0);
458}
459
460int
461posix_spawnattr_setschedpolicy(posix_spawnattr_t *sa, int schedpolicy)
462{
463	(*sa)->sa_schedpolicy = schedpolicy;
464	return (0);
465}
466
467int
468posix_spawnattr_setsigdefault(posix_spawnattr_t * __restrict sa,
469    const sigset_t * __restrict sigdefault)
470{
471	(*sa)->sa_sigdefault = *sigdefault;
472	return (0);
473}
474
475int
476posix_spawnattr_setsigmask(posix_spawnattr_t * __restrict sa,
477    const sigset_t * __restrict sigmask)
478{
479	(*sa)->sa_sigmask = *sigmask;
480	return (0);
481}
482