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/cdefs.h>
42 __FBSDID("$FreeBSD: stable/12/usr.sbin/autofs/popen.c 328338 2018-01-24 16:39:02Z trasz $");
43
44 #include <sys/param.h>
45 #include <sys/queue.h>
46 #include <sys/wait.h>
47
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <unistd.h>
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <paths.h>
56
57 #include "common.h"
58
59 extern char **environ;
60
61 struct pid {
62 SLIST_ENTRY(pid) next;
63 FILE *outfp;
64 pid_t pid;
65 char *command;
66 };
67 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
68
69 #define ARGV_LEN 42
70
71 /*
72 * Replacement for popen(3), without stdin (which we do not use), but with
73 * stderr, proper logging, and improved command line arguments passing.
74 * Error handling is built in - if it returns, then it succeeded.
75 */
76 FILE *
auto_popen(const char * argv0,...)77 auto_popen(const char *argv0, ...)
78 {
79 va_list ap;
80 struct pid *cur, *p;
81 pid_t pid;
82 int error, i, nullfd, outfds[2];
83 char *arg, *argv[ARGV_LEN], *command;
84
85 nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
86 if (nullfd < 0)
87 log_err(1, "cannot open %s", _PATH_DEVNULL);
88
89 error = pipe(outfds);
90 if (error != 0)
91 log_err(1, "pipe");
92
93 cur = malloc(sizeof(struct pid));
94 if (cur == NULL)
95 log_err(1, "malloc");
96
97 argv[0] = checked_strdup(argv0);
98 command = argv[0];
99
100 va_start(ap, argv0);
101 for (i = 1;; i++) {
102 if (i >= ARGV_LEN)
103 log_errx(1, "too many arguments to auto_popen");
104 arg = va_arg(ap, char *);
105 argv[i] = arg;
106 if (arg == NULL)
107 break;
108
109 command = concat(command, ' ', arg);
110 }
111 va_end(ap);
112
113 cur->command = checked_strdup(command);
114
115 switch (pid = fork()) {
116 case -1: /* Error. */
117 log_err(1, "fork");
118 /* NOTREACHED */
119 case 0: /* Child. */
120 dup2(nullfd, STDIN_FILENO);
121 dup2(outfds[1], STDOUT_FILENO);
122
123 close(nullfd);
124 close(outfds[0]);
125 close(outfds[1]);
126
127 SLIST_FOREACH(p, &pidlist, next)
128 close(fileno(p->outfp));
129 execvp(argv[0], argv);
130 log_err(1, "failed to execute %s", argv[0]);
131 /* NOTREACHED */
132 }
133
134 log_debugx("executing \"%s\" as pid %d", command, pid);
135
136 /* Parent; assume fdopen cannot fail. */
137 cur->outfp = fdopen(outfds[0], "r");
138 close(nullfd);
139 close(outfds[1]);
140
141 /* Link into list of file descriptors. */
142 cur->pid = pid;
143 SLIST_INSERT_HEAD(&pidlist, cur, next);
144
145 return (cur->outfp);
146 }
147
148 int
auto_pclose(FILE * iop)149 auto_pclose(FILE *iop)
150 {
151 struct pid *cur, *last = NULL;
152 int status;
153 pid_t pid;
154
155 /*
156 * Find the appropriate file pointer and remove it from the list.
157 */
158 SLIST_FOREACH(cur, &pidlist, next) {
159 if (cur->outfp == iop)
160 break;
161 last = cur;
162 }
163 if (cur == NULL) {
164 return (-1);
165 }
166 if (last == NULL)
167 SLIST_REMOVE_HEAD(&pidlist, next);
168 else
169 SLIST_REMOVE_AFTER(last, next);
170
171 fclose(cur->outfp);
172
173 do {
174 pid = wait4(cur->pid, &status, 0, NULL);
175 } while (pid == -1 && errno == EINTR);
176
177 if (WIFSIGNALED(status)) {
178 log_warnx("\"%s\", pid %d, terminated with signal %d",
179 cur->command, pid, WTERMSIG(status));
180 return (status);
181 }
182
183 if (WEXITSTATUS(status) != 0) {
184 log_warnx("\"%s\", pid %d, terminated with exit status %d",
185 cur->command, pid, WEXITSTATUS(status));
186 return (status);
187 }
188
189 log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid);
190
191 free(cur->command);
192 free(cur);
193
194 return (pid == -1 ? -1 : status);
195 }
196