1/*
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 * Copyright (c) 2014 The FreeBSD Foundation
5 * All rights reserved.
6 *
7 * This code is derived from software written by Ken Arnold and
8 * published in UNIX Review, Vol. 6, No. 8.
9 *
10 * Portions of this software were developed by Edward Tomasz Napierala
11 * under sponsorship from the FreeBSD Foundation.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 4. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD$");
41
42#include <sys/param.h>
43#include <sys/queue.h>
44#include <sys/wait.h>
45
46#include <errno.h>
47#include <fcntl.h>
48#include <unistd.h>
49#include <stdarg.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <string.h>
53#include <paths.h>
54
55#include "common.h"
56
57extern char **environ;
58
59struct pid {
60	SLIST_ENTRY(pid) next;
61	FILE *outfp;
62	pid_t pid;
63	char *command;
64};
65static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
66
67#define	ARGV_LEN	42
68
69/*
70 * Replacement for popen(3), without stdin (which we do not use), but with
71 * stderr, proper logging, and improved command line arguments passing.
72 * Error handling is built in - if it returns, then it succeeded.
73 */
74FILE *
75auto_popen(const char *argv0, ...)
76{
77	va_list ap;
78	struct pid *cur, *p;
79	pid_t pid;
80	int error, i, nullfd, outfds[2];
81	char *arg, *argv[ARGV_LEN], *command;
82
83	nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
84	if (nullfd < 0)
85		log_err(1, "cannot open %s", _PATH_DEVNULL);
86
87	error = pipe(outfds);
88	if (error != 0)
89		log_err(1, "pipe");
90
91	cur = malloc(sizeof(struct pid));
92	if (cur == NULL)
93		log_err(1, "malloc");
94
95	argv[0] = checked_strdup(argv0);
96	command = argv[0];
97
98	va_start(ap, argv0);
99	for (i = 1;; i++) {
100		if (i >= ARGV_LEN)
101			log_errx(1, "too many arguments to auto_popen");
102		arg = va_arg(ap, char *);
103		argv[i] = arg;
104		if (arg == NULL)
105			break;
106
107		command = separated_concat(command, arg, ' ');
108	}
109	va_end(ap);
110
111	cur->command = checked_strdup(command);
112
113	switch (pid = fork()) {
114	case -1:			/* Error. */
115		log_err(1, "fork");
116		/* NOTREACHED */
117	case 0:				/* Child. */
118		dup2(nullfd, STDIN_FILENO);
119		dup2(outfds[1], STDOUT_FILENO);
120
121		close(nullfd);
122		close(outfds[0]);
123		close(outfds[1]);
124
125		SLIST_FOREACH(p, &pidlist, next)
126			close(fileno(p->outfp));
127		execvp(argv[0], argv);
128		log_err(1, "failed to execute %s", argv[0]);
129		/* NOTREACHED */
130	}
131
132	log_debugx("executing \"%s\" as pid %d", command, pid);
133
134	/* Parent; assume fdopen cannot fail. */
135	cur->outfp = fdopen(outfds[0], "r");
136	close(nullfd);
137	close(outfds[1]);
138
139	/* Link into list of file descriptors. */
140	cur->pid = pid;
141	SLIST_INSERT_HEAD(&pidlist, cur, next);
142
143	return (cur->outfp);
144}
145
146int
147auto_pclose(FILE *iop)
148{
149	struct pid *cur, *last = NULL;
150	int status;
151	pid_t pid;
152
153	/*
154	 * Find the appropriate file pointer and remove it from the list.
155	 */
156	SLIST_FOREACH(cur, &pidlist, next) {
157		if (cur->outfp == iop)
158			break;
159		last = cur;
160	}
161	if (cur == NULL) {
162		return (-1);
163	}
164	if (last == NULL)
165		SLIST_REMOVE_HEAD(&pidlist, next);
166	else
167		SLIST_REMOVE_AFTER(last, next);
168
169	fclose(cur->outfp);
170
171	do {
172		pid = wait4(cur->pid, &status, 0, NULL);
173	} while (pid == -1 && errno == EINTR);
174
175	if (WIFSIGNALED(status)) {
176		log_warnx("\"%s\", pid %d, terminated with signal %d",
177		    cur->command, pid, WTERMSIG(status));
178		return (status);
179	}
180
181	if (WEXITSTATUS(status) != 0) {
182		log_warnx("\"%s\", pid %d, terminated with exit status %d",
183		    cur->command, pid, WEXITSTATUS(status));
184		return (status);
185	}
186
187	log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid);
188
189	free(cur->command);
190	free(cur);
191
192	return (pid == -1 ? -1 : status);
193}
194