1 /* $NetBSD: popen.c,v 1.1 2018/01/09 03:31:15 christos Exp $ */
2
3 /*
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 * Copyright (c) 2017 The NetBSD Foundation, Inc.
7 * Copyright (c) 2016 The DragonFly Project
8 * Copyright (c) 2014 The FreeBSD Foundation
9 * All rights reserved.
10 *
11 * This code is derived from software contributed to The NetBSD Foundation
12 * by Tomohiro Kusumi <kusumi.tomohiro@gmail.com>.
13 *
14 * This code is derived from software written by Ken Arnold and
15 * published in UNIX Review, Vol. 6, No. 8.
16 *
17 * Portions of this software were developed by Edward Tomasz Napierala
18 * under sponsorship from the FreeBSD Foundation.
19 *
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
22 * are met:
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 * 3. Neither the name of the University nor the names of its contributors
29 * may be used to endorse or promote products derived from this software
30 * without specific prior written permission.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 * SUCH DAMAGE.
43 *
44 */
45 #include <sys/cdefs.h>
46 __RCSID("$NetBSD: popen.c,v 1.1 2018/01/09 03:31:15 christos Exp $");
47
48 #include <sys/types.h>
49 #include <sys/queue.h>
50 #include <sys/wait.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <paths.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "common.h"
61
62 extern char **environ;
63
64 struct pid {
65 SLIST_ENTRY(pid) next;
66 FILE *outfp;
67 pid_t pid;
68 char *command;
69 };
70 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
71
72 #define ARGV_LEN 42
73
74 /*
75 * Replacement for popen(3), without stdin (which we do not use), but with
76 * stderr, proper logging, and improved command line arguments passing.
77 * Error handling is built in - if it returns, then it succeeded.
78 */
79 FILE *
auto_popen(const char * argv0,...)80 auto_popen(const char *argv0, ...)
81 {
82 va_list ap;
83 struct pid *cur, *p;
84 pid_t pid;
85 int error, i, nullfd, outfds[2];
86 char *arg, *argv[ARGV_LEN], *command;
87
88 nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
89 if (nullfd < 0)
90 log_err(1, "cannot open %s", _PATH_DEVNULL);
91
92 error = pipe(outfds);
93 if (error != 0)
94 log_err(1, "pipe");
95
96 cur = malloc(sizeof(struct pid));
97 if (cur == NULL)
98 log_err(1, "malloc");
99
100 argv[0] = checked_strdup(argv0);
101 command = argv[0];
102
103 va_start(ap, argv0);
104 for (i = 1;; i++) {
105 if (i >= ARGV_LEN)
106 log_errx(1, "too many arguments to auto_popen");
107 arg = va_arg(ap, char *);
108 argv[i] = arg;
109 if (arg == NULL)
110 break;
111
112 command = concat(command, ' ', arg);
113 }
114 va_end(ap);
115
116 cur->command = checked_strdup(command);
117
118 switch (pid = fork()) {
119 case -1: /* Error. */
120 log_err(1, "fork");
121 /* NOTREACHED */
122 case 0: /* Child. */
123 dup2(nullfd, STDIN_FILENO);
124 dup2(outfds[1], STDOUT_FILENO);
125
126 close(nullfd);
127 close(outfds[0]);
128 close(outfds[1]);
129
130 SLIST_FOREACH(p, &pidlist, next)
131 close(fileno(p->outfp));
132 execvp(argv[0], argv);
133 log_err(1, "failed to execute %s", argv[0]);
134 /* NOTREACHED */
135 }
136
137 log_debugx("executing \"%s\" as pid %d", command, pid);
138
139 /* Parent; assume fdopen cannot fail. */
140 cur->outfp = fdopen(outfds[0], "r");
141 close(nullfd);
142 close(outfds[1]);
143
144 /* Link into list of file descriptors. */
145 cur->pid = pid;
146 SLIST_INSERT_HEAD(&pidlist, cur, next);
147
148 return cur->outfp;
149 }
150
151 int
auto_pclose(FILE * iop)152 auto_pclose(FILE *iop)
153 {
154 struct pid *cur, *last = NULL;
155 int status;
156 pid_t pid;
157
158 /*
159 * Find the appropriate file pointer and remove it from the list.
160 */
161 SLIST_FOREACH(cur, &pidlist, next) {
162 if (cur->outfp == iop)
163 break;
164 last = cur;
165 }
166 if (cur == NULL) {
167 return -1;
168 }
169 if (last == NULL)
170 SLIST_REMOVE_HEAD(&pidlist, next);
171 else
172 SLIST_REMOVE_AFTER(last, next);
173
174 fclose(cur->outfp);
175
176 do {
177 pid = wait4(cur->pid, &status, 0, NULL);
178 } while (pid == -1 && errno == EINTR);
179
180 if (WIFSIGNALED(status)) {
181 log_warnx("\"%s\", pid %d, terminated with signal %d",
182 cur->command, pid, WTERMSIG(status));
183 return status;
184 }
185
186 if (WEXITSTATUS(status) != 0) {
187 log_warnx("\"%s\", pid %d, terminated with exit status %d",
188 cur->command, pid, WEXITSTATUS(status));
189 return status;
190 }
191
192 log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid);
193
194 free(cur->command);
195 free(cur);
196
197 return pid == -1 ? -1 : status;
198 }
199