xref: /netbsd/usr.bin/mail/popen.c (revision bf9ec67e) 
1 /*	$NetBSD: popen.c,v 1.14 2002/03/05 21:29:30 wiz Exp $	*/
2 
3 /*
4  * Copyright (c) 1980, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)popen.c	8.1 (Berkeley) 6/6/93";
40 #else
41 __RCSID("$NetBSD: popen.c,v 1.14 2002/03/05 21:29:30 wiz Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include "rcv.h"
46 #include "extern.h"
47 
48 #define READ 0
49 #define WRITE 1
50 
51 struct fp {
52 	FILE *fp;
53 	int pipe;
54 	int pid;
55 	struct fp *link;
56 };
57 static struct fp *fp_head;
58 
59 struct child {
60 	int pid;
61 	char done;
62 	char free;
63 	int status;
64 	struct child *link;
65 };
66 static struct child *child;
67 static struct child *findchild(int);
68 static void delchild(struct child *);
69 static int file_pid(FILE *);
70 
71 FILE *
72 Fopen(char *fn, char *mode)
73 {
74 	FILE *fp;
75 
76 	if ((fp = fopen(fn, mode)) != NULL) {
77 		register_file(fp, 0, 0);
78 		(void)fcntl(fileno(fp), F_SETFD, 1);
79 	}
80 	return fp;
81 }
82 
83 FILE *
84 Fdopen(int fd, char *mode)
85 {
86 	FILE *fp;
87 
88 	if ((fp = fdopen(fd, mode)) != NULL) {
89 		register_file(fp, 0, 0);
90 		(void)fcntl(fileno(fp), F_SETFD, 1);
91 	}
92 	return fp;
93 }
94 
95 int
96 Fclose(FILE *fp)
97 {
98 	unregister_file(fp);
99 	return fclose(fp);
100 }
101 
102 FILE *
103 Popen(char *cmd, char *mode)
104 {
105 	int p[2];
106 	int myside, hisside, fd0, fd1;
107 	int pid;
108 	sigset_t nset;
109 	FILE *fp;
110 
111 	if (pipe(p) < 0)
112 		return NULL;
113 	(void)fcntl(p[READ], F_SETFD, 1);
114 	(void)fcntl(p[WRITE], F_SETFD, 1);
115 	if (*mode == 'r') {
116 		myside = p[READ];
117 		fd0 = -1;
118 		hisside = fd1 = p[WRITE];
119 	} else {
120 		myside = p[WRITE];
121 		hisside = fd0 = p[READ];
122 		fd1 = -1;
123 	}
124 	sigemptyset(&nset);
125 	if ((pid = start_command(cmd, &nset, fd0, fd1, NULL, NULL, NULL)) < 0) {
126 		close(p[READ]);
127 		close(p[WRITE]);
128 		return NULL;
129 	}
130 	(void)close(hisside);
131 	if ((fp = fdopen(myside, mode)) != NULL)
132 		register_file(fp, 1, pid);
133 	return fp;
134 }
135 
136 int
137 Pclose(FILE *ptr)
138 {
139 	int i;
140 	sigset_t nset, oset;
141 
142 	i = file_pid(ptr);
143 	unregister_file(ptr);
144 	(void)fclose(ptr);
145 	sigemptyset(&nset);
146 	sigaddset(&nset, SIGINT);
147 	sigaddset(&nset, SIGHUP);
148 	sigprocmask(SIG_BLOCK, &nset, &oset);
149 	i = wait_child(i);
150 	sigprocmask(SIG_SETMASK, &oset, NULL);
151 	return i;
152 }
153 
154 void
155 close_all_files(void)
156 {
157 
158 	while (fp_head)
159 		if (fp_head->pipe)
160 			(void)Pclose(fp_head->fp);
161 		else
162 			(void)Fclose(fp_head->fp);
163 }
164 
165 void
166 register_file(FILE *fp, int pipefd, int pid)
167 {
168 	struct fp *fpp;
169 
170 	if ((fpp = (struct fp *) malloc(sizeof *fpp)) == NULL)
171 		errx(1, "Out of memory");
172 	fpp->fp = fp;
173 	fpp->pipe = pipefd;
174 	fpp->pid = pid;
175 	fpp->link = fp_head;
176 	fp_head = fpp;
177 }
178 
179 void
180 unregister_file(FILE *fp)
181 {
182 	struct fp **pp, *p;
183 
184 	for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
185 		if (p->fp == fp) {
186 			*pp = p->link;
187 			free((char *) p);
188 			return;
189 		}
190 	errx(1, "Invalid file pointer");
191 }
192 
193 static int
194 file_pid(FILE *fp)
195 {
196 	struct fp *p;
197 
198 	for (p = fp_head; p; p = p->link)
199 		if (p->fp == fp)
200 			return (p->pid);
201 	errx(1, "Invalid file pointer");
202 	/*NOTREACHED*/
203 }
204 
205 /*
206  * Run a command without a shell, with optional arguments and splicing
207  * of stdin and stdout.  The command name can be a sequence of words.
208  * Signals must be handled by the caller.
209  * "Mask" contains the signals to ignore in the new process.
210  * SIGINT is enabled unless it's in the mask.
211  */
212 /*VARARGS4*/
213 int
214 run_command(char *cmd, sigset_t *mask, int infd, int outfd, char *a0,
215 	    char *a1, char *a2)
216 {
217 	int pid;
218 
219 	if ((pid = start_command(cmd, mask, infd, outfd, a0, a1, a2)) < 0)
220 		return -1;
221 	return wait_command(pid);
222 }
223 
224 /*VARARGS4*/
225 int
226 start_command(char *cmd, sigset_t *mask, int infd, int outfd,
227 	      char *a0, char *a1, char *a2)
228 {
229 	int pid;
230 
231 	if ((pid = vfork()) < 0) {
232 		warn("fork");
233 		return -1;
234 	}
235 	if (pid == 0) {
236 		char *argv[100];
237 		int i = getrawlist(cmd, argv, sizeof argv / sizeof *argv);
238 
239 		if ((argv[i++] = a0) != NULL &&
240 		    (argv[i++] = a1) != NULL &&
241 		    (argv[i++] = a2) != NULL)
242 			argv[i] = NULL;
243 		prepare_child(mask, infd, outfd);
244 		execvp(argv[0], argv);
245 		warn("%s", argv[0]);
246 		_exit(1);
247 	}
248 	return pid;
249 }
250 
251 void
252 prepare_child(sigset_t *nset, int infd, int outfd)
253 {
254 	int i;
255 	sigset_t eset;
256 
257 	/*
258 	 * All file descriptors other than 0, 1, and 2 are supposed to be
259 	 * close-on-exec.
260 	 */
261 	if (infd >= 0)
262 		dup2(infd, 0);
263 	if (outfd >= 0)
264 		dup2(outfd, 1);
265 	for (i = 1; i < NSIG; i++)
266 		if (nset != NULL && sigismember(nset, i))
267 			(void)signal(i, SIG_IGN);
268 	if (nset == NULL || !sigismember(nset, SIGINT))
269 		(void)signal(SIGINT, SIG_DFL);
270 	sigemptyset(&eset);
271 	(void)sigprocmask(SIG_SETMASK, &eset, NULL);
272 }
273 
274 int
275 wait_command(int pid)
276 {
277 
278 	if (wait_child(pid) < 0) {
279 		printf("Fatal error in process.\n");
280 		return -1;
281 	}
282 	return 0;
283 }
284 
285 static struct child *
286 findchild(int pid)
287 {
288 	struct child **cpp;
289 
290 	for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
291 	     cpp = &(*cpp)->link)
292 			;
293 	if (*cpp == NULL) {
294 		*cpp = (struct child *) malloc(sizeof (struct child));
295 		(*cpp)->pid = pid;
296 		(*cpp)->done = (*cpp)->free = 0;
297 		(*cpp)->link = NULL;
298 	}
299 	return *cpp;
300 }
301 
302 static void
303 delchild(struct child *cp)
304 {
305 	struct child **cpp;
306 
307 	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
308 		;
309 	*cpp = cp->link;
310 	free((char *) cp);
311 }
312 
313 void
314 sigchild(int signo)
315 {
316 	int pid;
317 	int status;
318 	struct child *cp;
319 
320 	while ((pid = wait3(&status, WNOHANG, NULL)) > 0) {
321 		cp = findchild(pid);
322 		if (cp->free)
323 			delchild(cp);
324 		else {
325 			cp->done = 1;
326 			cp->status = status;
327 		}
328 	}
329 }
330 
331 int wait_status;
332 
333 /*
334  * Wait for a specific child to die.
335  */
336 int
337 wait_child(int pid)
338 {
339 	sigset_t nset, oset;
340 	struct child *cp = findchild(pid);
341 	sigemptyset(&nset);
342 	sigaddset(&nset, SIGCHLD);
343 	sigprocmask(SIG_BLOCK, &nset, &oset);
344 
345 	while (!cp->done)
346 		sigsuspend(&oset);
347 	wait_status = cp->status;
348 	delchild(cp);
349 	sigprocmask(SIG_SETMASK, &oset, NULL);
350 	return wait_status ? -1 : 0;
351 }
352 
353 /*
354  * Mark a child as don't care.
355  */
356 void
357 free_child(int pid)
358 {
359 	sigset_t nset, oset;
360 	struct child *cp = findchild(pid);
361 	sigemptyset(&nset);
362 	sigaddset(&nset, SIGCHLD);
363 	sigprocmask(SIG_BLOCK, &nset, &oset);
364 
365 	if (cp->done)
366 		delchild(cp);
367 	else
368 		cp->free = 1;
369 	sigprocmask(SIG_SETMASK, &oset, NULL);
370 }
371