popen.c revision 77274 
1/*
2 * Copyright (c) 1980, 1993
3 *	The Regents of the University of California.  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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35#if 0
36static char sccsid[] = "@(#)popen.c	8.1 (Berkeley) 6/6/93";
37#endif
38static const char rcsid[] =
39  "$FreeBSD: head/usr.bin/mail/popen.c 77274 2001-05-27 20:26:22Z mikeh $";
40#endif /* not lint */
41
42#include "rcv.h"
43#include <sys/wait.h>
44#include <fcntl.h>
45#include "extern.h"
46
47#define READ 0
48#define WRITE 1
49
50struct fp {
51	FILE	*fp;
52	int	pipe;
53	int	pid;
54	struct	fp *link;
55};
56static struct fp *fp_head;
57
58struct child {
59	int	pid;
60	char	done;
61	char	free;
62	int	status;
63	struct	child *link;
64};
65static struct child *child;
66static struct child *findchild __P((int));
67static void delchild __P((struct child *));
68static int file_pid __P((FILE *));
69
70FILE *
71Fopen(path, mode)
72	const char *path, *mode;
73{
74	FILE *fp;
75
76	if ((fp = fopen(path, mode)) != NULL) {
77		register_file(fp, 0, 0);
78		(void)fcntl(fileno(fp), F_SETFD, 1);
79	}
80	return (fp);
81}
82
83FILE *
84Fdopen(fd, mode)
85	int fd;
86	const char *mode;
87{
88	FILE *fp;
89
90	if ((fp = fdopen(fd, mode)) != NULL) {
91		register_file(fp, 0, 0);
92		(void)fcntl(fileno(fp), F_SETFD, 1);
93	}
94	return (fp);
95}
96
97int
98Fclose(fp)
99	FILE *fp;
100{
101	unregister_file(fp);
102	return (fclose(fp));
103}
104
105FILE *
106Popen(cmd, mode)
107	char *cmd;
108	const char *mode;
109{
110	int p[2];
111	int myside, hisside, fd0, fd1;
112	int pid;
113	FILE *fp;
114
115	if (pipe(p) < 0)
116		return (NULL);
117	(void)fcntl(p[READ], F_SETFD, 1);
118	(void)fcntl(p[WRITE], F_SETFD, 1);
119	if (*mode == 'r') {
120		myside = p[READ];
121		fd0 = -1;
122		hisside = fd1 = p[WRITE];
123	} else {
124		myside = p[WRITE];
125		hisside = fd0 = p[READ];
126		fd1 = -1;
127	}
128	if ((pid = start_command(cmd, 0, fd0, fd1, NULL, NULL, NULL)) < 0) {
129		(void)close(p[READ]);
130		(void)close(p[WRITE]);
131		return (NULL);
132	}
133	(void)close(hisside);
134	if ((fp = fdopen(myside, mode)) != NULL)
135		register_file(fp, 1, pid);
136	return (fp);
137}
138
139int
140Pclose(ptr)
141	FILE *ptr;
142{
143	int i;
144	int omask;
145
146	i = file_pid(ptr);
147	unregister_file(ptr);
148	(void)fclose(ptr);
149	omask = sigblock(sigmask(SIGINT)|sigmask(SIGHUP));
150	i = wait_child(i);
151	(void)sigsetmask(omask);
152	return (i);
153}
154
155void
156close_all_files()
157{
158
159	while (fp_head != NULL)
160		if (fp_head->pipe)
161			(void)Pclose(fp_head->fp);
162		else
163			(void)Fclose(fp_head->fp);
164}
165
166void
167register_file(fp, pipe, pid)
168	FILE *fp;
169	int pipe, pid;
170{
171	struct fp *fpp;
172
173	if ((fpp = malloc(sizeof(*fpp))) == NULL)
174		err(1, "Out of memory");
175	fpp->fp = fp;
176	fpp->pipe = pipe;
177	fpp->pid = pid;
178	fpp->link = fp_head;
179	fp_head = fpp;
180}
181
182void
183unregister_file(fp)
184	FILE *fp;
185{
186	struct fp **pp, *p;
187
188	for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
189		if (p->fp == fp) {
190			*pp = p->link;
191			(void)free(p);
192			return;
193		}
194	errx(1, "Invalid file pointer");
195	/*NOTREACHED*/
196}
197
198int
199file_pid(fp)
200	FILE *fp;
201{
202	struct fp *p;
203
204	for (p = fp_head; p != NULL; p = p->link)
205		if (p->fp == fp)
206			return (p->pid);
207	errx(1, "Invalid file pointer");
208	/*NOTREACHED*/
209}
210
211/*
212 * Run a command without a shell, with optional arguments and splicing
213 * of stdin and stdout.  The command name can be a sequence of words.
214 * Signals must be handled by the caller.
215 * "Mask" contains the signals to ignore in the new process.
216 * SIGINT is enabled unless it's in the mask.
217 */
218/*VARARGS4*/
219int
220run_command(cmd, mask, infd, outfd, a0, a1, a2)
221	char *cmd;
222	int mask, infd, outfd;
223	char *a0, *a1, *a2;
224{
225	int pid;
226
227	if ((pid = start_command(cmd, mask, infd, outfd, a0, a1, a2)) < 0)
228		return (-1);
229	return (wait_command(pid));
230}
231
232/*VARARGS4*/
233int
234start_command(cmd, mask, infd, outfd, a0, a1, a2)
235	char *cmd;
236	int mask, infd, outfd;
237	char *a0, *a1, *a2;
238{
239	int pid;
240
241	if ((pid = fork()) < 0) {
242		warn("fork");
243		return (-1);
244	}
245	if (pid == 0) {
246		char *argv[100];
247		int i = getrawlist(cmd, argv, sizeof(argv) / sizeof(*argv));
248
249		if ((argv[i++] = a0) != NULL &&
250		    (argv[i++] = a1) != NULL &&
251		    (argv[i++] = a2) != NULL)
252			argv[i] = NULL;
253		prepare_child(mask, infd, outfd);
254		execvp(argv[0], argv);
255		warn("%s", argv[0]);
256		_exit(1);
257	}
258	return (pid);
259}
260
261void
262prepare_child(mask, infd, outfd)
263	int mask, infd, outfd;
264{
265	int i;
266
267	/*
268	 * All file descriptors other than 0, 1, and 2 are supposed to be
269	 * close-on-exec.
270	 */
271	if (infd >= 0)
272		dup2(infd, 0);
273	if (outfd >= 0)
274		dup2(outfd, 1);
275	for (i = 1; i <= NSIG; i++)
276		if (mask & sigmask(i))
277			(void)signal(i, SIG_IGN);
278	if ((mask & sigmask(SIGINT)) == 0)
279		(void)signal(SIGINT, SIG_DFL);
280	(void)sigsetmask(0);
281}
282
283int
284wait_command(pid)
285	int pid;
286{
287
288	if (wait_child(pid) < 0) {
289		printf("Fatal error in process.\n");
290		return (-1);
291	}
292	return (0);
293}
294
295static struct child *
296findchild(pid)
297	int pid;
298{
299	struct child **cpp;
300
301	for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
302	    cpp = &(*cpp)->link)
303			;
304	if (*cpp == NULL) {
305		*cpp = malloc(sizeof(struct child));
306		if (*cpp == NULL)
307			err(1, "Out of memory");
308		(*cpp)->pid = pid;
309		(*cpp)->done = (*cpp)->free = 0;
310		(*cpp)->link = NULL;
311	}
312	return (*cpp);
313}
314
315static void
316delchild(cp)
317	struct child *cp;
318{
319	struct child **cpp;
320
321	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
322		;
323	*cpp = cp->link;
324	(void)free(cp);
325}
326
327/*ARGSUSED*/
328void
329sigchild(signo)
330	int signo;
331{
332	int pid;
333	int status;
334	struct child *cp;
335
336	while ((pid = waitpid((pid_t)-1, &status, WNOHANG)) > 0) {
337		cp = findchild(pid);
338		if (cp->free)
339			delchild(cp);
340		else {
341			cp->done = 1;
342			cp->status = status;
343		}
344	}
345}
346
347int wait_status;
348
349/*
350 * Wait for a specific child to die.
351 */
352int
353wait_child(pid)
354	int pid;
355{
356	int mask = sigblock(sigmask(SIGCHLD));
357	struct child *cp = findchild(pid);
358
359	while (!cp->done)
360		sigpause(mask);
361	wait_status = cp->status;
362	delchild(cp);
363	(void)sigsetmask(mask);
364	return ((WIFEXITED(wait_status) && WEXITSTATUS(wait_status)) ? -1 : 0);
365}
366
367/*
368 * Mark a child as don't care.
369 */
370void
371free_child(pid)
372	int pid;
373{
374	int mask = sigblock(sigmask(SIGCHLD));
375	struct child *cp = findchild(pid);
376
377	if (cp->done)
378		delchild(cp);
379	else
380		cp->free = 1;
381	(void)sigsetmask(mask);
382}
383