1/*
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 * Copyright (c) 2014 The FreeBSD Foundation
7 * All rights reserved.
8 *
9 * This code is derived from software written by Ken Arnold and
10 * published in UNIX Review, Vol. 6, No. 8.
11 *
12 * Portions of this software were developed by Edward Tomasz Napierala
13 * under sponsorship from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 *    notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 *    notice, this list of conditions and the following disclaimer in the
22 *    documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 */
40
41#include <sys/param.h>
42#include <sys/queue.h>
43#include <sys/wait.h>
44
45#include <errno.h>
46#include <fcntl.h>
47#include <unistd.h>
48#include <stdarg.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <string.h>
52#include <paths.h>
53
54#include "common.h"
55
56extern char **environ;
57
58struct pid {
59	SLIST_ENTRY(pid) next;
60	FILE *outfp;
61	pid_t pid;
62	char *command;
63};
64static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
65
66#define	ARGV_LEN	42
67
68/*
69 * Replacement for popen(3), without stdin (which we do not use), but with
70 * stderr, proper logging, and improved command line arguments passing.
71 * Error handling is built in - if it returns, then it succeeded.
72 */
73FILE *
74auto_popen(const char *argv0, ...)
75{
76	va_list ap;
77	struct pid *cur, *p;
78	pid_t pid;
79	int error, i, nullfd, outfds[2];
80	char *arg, *argv[ARGV_LEN], *command;
81
82	nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
83	if (nullfd < 0)
84		log_err(1, "cannot open %s", _PATH_DEVNULL);
85
86	error = pipe(outfds);
87	if (error != 0)
88		log_err(1, "pipe");
89
90	cur = malloc(sizeof(struct pid));
91	if (cur == NULL)
92		log_err(1, "malloc");
93
94	argv[0] = checked_strdup(argv0);
95	command = argv[0];
96
97	va_start(ap, argv0);
98	for (i = 1;; i++) {
99		if (i >= ARGV_LEN)
100			log_errx(1, "too many arguments to auto_popen");
101		arg = va_arg(ap, char *);
102		argv[i] = arg;
103		if (arg == NULL)
104			break;
105
106		command = concat(command, ' ', arg);
107	}
108	va_end(ap);
109
110	cur->command = checked_strdup(command);
111
112	switch (pid = fork()) {
113	case -1:			/* Error. */
114		log_err(1, "fork");
115		/* NOTREACHED */
116	case 0:				/* Child. */
117		dup2(nullfd, STDIN_FILENO);
118		dup2(outfds[1], STDOUT_FILENO);
119
120		close(nullfd);
121		close(outfds[0]);
122		close(outfds[1]);
123
124		SLIST_FOREACH(p, &pidlist, next)
125			close(fileno(p->outfp));
126		execvp(argv[0], argv);
127		log_err(1, "failed to execute %s", argv[0]);
128		/* NOTREACHED */
129	}
130
131	log_debugx("executing \"%s\" as pid %d", command, pid);
132
133	/* Parent; assume fdopen cannot fail. */
134	cur->outfp = fdopen(outfds[0], "r");
135	close(nullfd);
136	close(outfds[1]);
137
138	/* Link into list of file descriptors. */
139	cur->pid = pid;
140	SLIST_INSERT_HEAD(&pidlist, cur, next);
141
142	return (cur->outfp);
143}
144
145int
146auto_pclose(FILE *iop)
147{
148	struct pid *cur, *last = NULL;
149	int status;
150	pid_t pid;
151
152	/*
153	 * Find the appropriate file pointer and remove it from the list.
154	 */
155	SLIST_FOREACH(cur, &pidlist, next) {
156		if (cur->outfp == iop)
157			break;
158		last = cur;
159	}
160	if (cur == NULL) {
161		return (-1);
162	}
163	if (last == NULL)
164		SLIST_REMOVE_HEAD(&pidlist, next);
165	else
166		SLIST_REMOVE_AFTER(last, next);
167
168	fclose(cur->outfp);
169
170	do {
171		pid = wait4(cur->pid, &status, 0, NULL);
172	} while (pid == -1 && errno == EINTR);
173
174	if (WIFSIGNALED(status)) {
175		log_warnx("\"%s\", pid %d, terminated with signal %d",
176		    cur->command, pid, WTERMSIG(status));
177		return (status);
178	}
179
180	if (WEXITSTATUS(status) != 0) {
181		log_warnx("\"%s\", pid %d, terminated with exit status %d",
182		    cur->command, pid, WEXITSTATUS(status));
183		return (status);
184	}
185
186	log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid);
187
188	free(cur->command);
189	free(cur);
190
191	return (pid == -1 ? -1 : status);
192}
193