1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef lint
33#if 0
34static char sccsid[] = "@(#)popen.c	8.1 (Berkeley) 6/6/93";
35#endif
36#endif /* not lint */
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD$");
39
40#include "rcv.h"
41#include <sys/wait.h>
42#include <fcntl.h>
43#include <errno.h>
44#include <stdarg.h>
45#include "extern.h"
46
47#define READ 0
48#define WRITE 1
49
50struct fp {
51	FILE	*fp;
52	int	pipe;
53	pid_t	pid;
54	struct	fp *link;
55};
56static struct fp *fp_head;
57
58struct child {
59	pid_t	pid;
60	char	done;
61	char	free;
62	int	status;
63	struct	child *link;
64};
65static struct child *child, *child_freelist = NULL;
66
67static void delchild(struct child *);
68static pid_t file_pid(FILE *);
69static pid_t start_commandv(char *, sigset_t *, int, int, va_list);
70
71FILE *
72Fopen(const char *path, const char *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(int fd, const 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
95int
96Fclose(FILE *fp)
97{
98
99	unregister_file(fp);
100	return (fclose(fp));
101}
102
103FILE *
104Popen(char *cmd, const char *mode)
105{
106	int p[2];
107	int myside, hisside, fd0, fd1;
108	pid_t pid;
109	sigset_t nset;
110	FILE *fp;
111
112	if (pipe(p) < 0)
113		return (NULL);
114	(void)fcntl(p[READ], F_SETFD, 1);
115	(void)fcntl(p[WRITE], F_SETFD, 1);
116	if (*mode == 'r') {
117		myside = p[READ];
118		hisside = fd0 = fd1 = p[WRITE];
119	} else {
120		myside = p[WRITE];
121		hisside = fd0 = p[READ];
122		fd1 = -1;
123	}
124	(void)sigemptyset(&nset);
125	pid = start_command(value("SHELL"), &nset, fd0, fd1, "-c", cmd, NULL);
126	if (pid < 0) {
127		(void)close(p[READ]);
128		(void)close(p[WRITE]);
129		return (NULL);
130	}
131	(void)close(hisside);
132	if ((fp = fdopen(myside, mode)) != NULL)
133		register_file(fp, 1, pid);
134	return (fp);
135}
136
137int
138Pclose(FILE *ptr)
139{
140	int i;
141	sigset_t nset, oset;
142
143	i = file_pid(ptr);
144	unregister_file(ptr);
145	(void)fclose(ptr);
146	(void)sigemptyset(&nset);
147	(void)sigaddset(&nset, SIGINT);
148	(void)sigaddset(&nset, SIGHUP);
149	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
150	i = wait_child(i);
151	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
152	return (i);
153}
154
155void
156close_all_files(void)
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(FILE *fp, int pipe, pid_t pid)
168{
169	struct fp *fpp;
170
171	if ((fpp = malloc(sizeof(*fpp))) == NULL)
172		err(1, "Out of memory");
173	fpp->fp = fp;
174	fpp->pipe = pipe;
175	fpp->pid = pid;
176	fpp->link = fp_head;
177	fp_head = fpp;
178}
179
180void
181unregister_file(FILE *fp)
182{
183	struct fp **pp, *p;
184
185	for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
186		if (p->fp == fp) {
187			*pp = p->link;
188			(void)free(p);
189			return;
190		}
191	errx(1, "Invalid file pointer");
192	/*NOTREACHED*/
193}
194
195pid_t
196file_pid(FILE *fp)
197{
198	struct fp *p;
199
200	for (p = fp_head; p != NULL; p = p->link)
201		if (p->fp == fp)
202			return (p->pid);
203	errx(1, "Invalid file pointer");
204	/*NOTREACHED*/
205}
206
207/*
208 * Run a command without a shell, with optional arguments and splicing
209 * of stdin (-1 means none) and stdout.  The command name can be a sequence
210 * of words.
211 * Signals must be handled by the caller.
212 * "nset" contains the signals to ignore in the new process.
213 * SIGINT is enabled unless it's in "nset".
214 */
215static pid_t
216start_commandv(char *cmd, sigset_t *nset, int infd, int outfd, va_list args)
217{
218	pid_t pid;
219
220	if ((pid = fork()) < 0) {
221		warn("fork");
222		return (-1);
223	}
224	if (pid == 0) {
225		char *argv[100];
226		int i = getrawlist(cmd, argv, sizeof(argv) / sizeof(*argv));
227
228		while ((argv[i++] = va_arg(args, char *)))
229			;
230		argv[i] = NULL;
231		prepare_child(nset, infd, outfd);
232		execvp(argv[0], argv);
233		warn("%s", argv[0]);
234		_exit(1);
235	}
236	return (pid);
237}
238
239int
240run_command(char *cmd, sigset_t *nset, int infd, int outfd, ...)
241{
242	pid_t pid;
243	va_list args;
244
245	va_start(args, outfd);
246	pid = start_commandv(cmd, nset, infd, outfd, args);
247	va_end(args);
248	if (pid < 0)
249		return -1;
250	return wait_command(pid);
251}
252
253int
254start_command(char *cmd, sigset_t *nset, int infd, int outfd, ...)
255{
256	va_list args;
257	int r;
258
259	va_start(args, outfd);
260	r = start_commandv(cmd, nset, infd, outfd, args);
261	va_end(args);
262	return r;
263}
264
265void
266prepare_child(sigset_t *nset, int infd, int outfd)
267{
268	int i;
269	sigset_t eset;
270
271	/*
272	 * All file descriptors other than 0, 1, and 2 are supposed to be
273	 * close-on-exec.
274	 */
275	if (infd >= 0)
276		dup2(infd, 0);
277	if (outfd >= 0)
278		dup2(outfd, 1);
279	for (i = 1; i < NSIG; i++)
280		if (nset != NULL && sigismember(nset, i))
281			(void)signal(i, SIG_IGN);
282	if (nset == NULL || !sigismember(nset, SIGINT))
283		(void)signal(SIGINT, SIG_DFL);
284	(void)sigemptyset(&eset);
285	(void)sigprocmask(SIG_SETMASK, &eset, NULL);
286}
287
288int
289wait_command(pid_t pid)
290{
291
292	if (wait_child(pid) < 0) {
293		printf("Fatal error in process.\n");
294		return (-1);
295	}
296	return (0);
297}
298
299static struct child *
300findchild(pid_t pid, int dont_alloc)
301{
302	struct child **cpp;
303
304	for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
305	    cpp = &(*cpp)->link)
306			;
307	if (*cpp == NULL) {
308		if (dont_alloc)
309			return(NULL);
310		if (child_freelist) {
311			*cpp = child_freelist;
312			child_freelist = (*cpp)->link;
313		} else {
314			*cpp = malloc(sizeof(struct child));
315			if (*cpp == NULL)
316				err(1, "malloc");
317		}
318		(*cpp)->pid = pid;
319		(*cpp)->done = (*cpp)->free = 0;
320		(*cpp)->link = NULL;
321	}
322	return (*cpp);
323}
324
325static void
326delchild(struct child *cp)
327{
328	struct child **cpp;
329
330	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
331		;
332	*cpp = cp->link;
333	cp->link = child_freelist;
334	child_freelist = cp;
335}
336
337/*ARGSUSED*/
338void
339sigchild(int signo __unused)
340{
341	pid_t pid;
342	int status;
343	struct child *cp;
344	int save_errno;
345
346	save_errno = errno;
347	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
348		cp = findchild(pid, 1);
349		if (cp == NULL)
350			continue;
351		if (cp->free)
352			delchild(cp);
353		else {
354			cp->done = 1;
355			cp->status = status;
356		}
357	}
358	errno = save_errno;
359}
360
361int wait_status;
362
363/*
364 * Wait for a specific child to die.
365 */
366int
367wait_child(pid_t pid)
368{
369	struct child *cp;
370	sigset_t nset, oset;
371	pid_t rv = 0;
372
373	(void)sigemptyset(&nset);
374	(void)sigaddset(&nset, SIGCHLD);
375	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
376	/*
377	 * If we have not already waited on the pid (via sigchild)
378	 * wait on it now.  Otherwise, use the wait status stashed
379	 * by sigchild.
380	 */
381	cp = findchild(pid, 1);
382	if (cp == NULL || !cp->done)
383		rv = waitpid(pid, &wait_status, 0);
384	else
385		wait_status = cp->status;
386	if (cp != NULL)
387		delchild(cp);
388	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
389	if (rv == -1 || (WIFEXITED(wait_status) && WEXITSTATUS(wait_status)))
390		return -1;
391	else
392		return 0;
393}
394
395/*
396 * Mark a child as don't care.
397 */
398void
399free_child(pid_t pid)
400{
401	struct child *cp;
402	sigset_t nset, oset;
403
404	(void)sigemptyset(&nset);
405	(void)sigaddset(&nset, SIGCHLD);
406	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
407	if ((cp = findchild(pid, 0)) != NULL) {
408		if (cp->done)
409			delchild(cp);
410		else
411			cp->free = 1;
412	}
413	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
414}
415