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
56 extern char **environ;
57
58 struct pid {
59 SLIST_ENTRY(pid) next;
60 FILE *outfp;
61 pid_t pid;
62 char *command;
63 };
64 static 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 */
73 FILE *
auto_popen(const char * argv0,...)74 auto_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
145 int
auto_pclose(FILE * iop)146 auto_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