1 /* $NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $ */
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software written by Ken Arnold and
8 * published in UNIX Review, Vol. 6, No. 8.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
42 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
44 __RCSID("$NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $");
46 #endif /* LIBC_SCCS and not lint */
48 #include <sys/param.h>
50 #include <sys/socket.h>
63 __weak_alias(popen,_popen)
64 __weak_alias(pclose,_pclose)
77 static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
81 pdes_get(int *pdes, const char **type)
84 int flags = strchr(*type, 'e') ? O_CLOEXEC : 0;
87 if (strchr(*type, '+')) {
89 #define SOCK_CLOEXEC 0
91 int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
93 if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
96 fcntl(pdes[0], F_SETFD, FD_CLOEXEC);
97 fcntl(pdes[1], F_SETFD, FD_CLOEXEC);
100 *type = strrchr(*type, 'r') ? "r" : "w";
101 #if SOCK_CLOEXEC != 0
102 if (pipe2(pdes, flags) == -1)
105 if (pipe(pdes) == -1)
107 fcntl(pdes[0], F_SETFL, fcntl(pdes[0], F_GETFL) | flags);
108 fcntl(pdes[1], F_SETFL, fcntl(pdes[1], F_GETFL) | flags);
112 if ((cur = malloc(sizeof(*cur))) != NULL)
115 (void)close(pdes[0]);
116 (void)close(pdes[1]);
122 pdes_child(int *pdes, const char *type)
126 /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
127 from previous popen() calls that remain open in the
128 parent process are closed in the new child process. */
129 for (old = pidlist; old; old = old->next)
131 (void)close(old->fd); /* don't allow a flush */
133 (void)close(fileno(old->fp)); /* don't allow a flush */
136 if (type[0] == 'r') {
137 (void)close(pdes[0]);
138 if (pdes[1] != STDOUT_FILENO) {
139 (void)dup2(pdes[1], STDOUT_FILENO);
140 (void)close(pdes[1]);
143 (void)dup2(STDOUT_FILENO, STDIN_FILENO);
145 (void)close(pdes[1]);
146 if (pdes[0] != STDIN_FILENO) {
147 (void)dup2(pdes[0], STDIN_FILENO);
148 (void)close(pdes[0]);
154 pdes_parent(int *pdes, struct pid *cur, pid_t pid, const char *type)
158 /* Parent; assume fdopen can't fail. */
160 iop = fdopen(pdes[0], type);
164 (void)close(pdes[1]);
166 iop = fdopen(pdes[1], type);
170 (void)close(pdes[0]);
173 /* Link into list of file descriptors. */
181 pdes_error(int *pdes, struct pid *cur)
184 (void)close(pdes[0]);
185 (void)close(pdes[1]);
189 popenve(const char *cmd, char *const *argv, char *const *envp, const char *type)
195 if ((cur = pdes_get(pdes, &type)) == NULL)
199 (void)rwlock_rdlock(&pidlist_lock);
201 switch (pid = vfork()) {
202 case -1: /* Error. */
205 (void)rwlock_unlock(&pidlist_lock);
207 pdes_error(pdes, cur);
212 pdes_child(pdes, type);
213 execve(cmd, argv, envp);
218 pdes_parent(pdes, cur, pid, type);
221 (void)rwlock_unlock(&pidlist_lock);
229 * Pclose returns -1 if stream is not associated with a `popened' command,
230 * if already `pclosed', or waitpid returns an error.
235 struct pid *cur, *last;
240 rwlock_wrlock(&pidlist_lock);
243 /* Find the appropriate file pointer. */
244 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
249 (void)rwlock_unlock(&pidlist_lock);
257 /* Remove the entry from the linked list. */
261 last->next = cur->next;
264 (void)rwlock_unlock(&pidlist_lock);
268 pid = waitpid(cur->pid, &pstat, 0);
269 } while (pid == -1 && errno == EINTR);
273 return pid == -1 ? -1 : pstat;