2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software written by Ken Arnold and
6 * published in UNIX Review, Vol. 6, No. 8.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include "namespace.h"
40 #include <sys/param.h>
41 #include <sys/queue.h>
53 #include "un-namespace.h"
54 #include "libc_private.h"
56 extern char **environ;
59 SLIST_ENTRY(pid) next;
63 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
64 static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
66 #define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
67 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex)
71 const char *command, *type;
75 int pdes[2], pid, twoway, cloexec;
76 int pdes_unused_in_parent;
80 cloexec = strchr(type, 'e') != NULL;
82 * Lite2 introduced two-way popen() pipes using _socketpair().
83 * FreeBSD's pipe() is bidirectional, so we use that.
85 if (strchr(type, '+')) {
90 if ((*type != 'r' && *type != 'w') ||
91 (type[1] && (type[1] != 'e' || type[2])))
94 if ((cloexec ? pipe2(pdes, O_CLOEXEC) : pipe(pdes)) < 0)
97 if ((cur = malloc(sizeof(struct pid))) == NULL) {
98 (void)_close(pdes[0]);
99 (void)_close(pdes[1]);
104 iop = fdopen(pdes[0], type);
105 pdes_unused_in_parent = pdes[1];
107 iop = fdopen(pdes[1], type);
108 pdes_unused_in_parent = pdes[0];
111 (void)_close(pdes[0]);
112 (void)_close(pdes[1]);
119 argv[2] = (char *)command;
123 switch (pid = vfork()) {
124 case -1: /* Error. */
127 * The _close() closes the unused end of pdes[], while
128 * the fclose() closes the used end of pdes[], *and* cleans
131 (void)_close(pdes_unused_in_parent);
139 * The _dup2() to STDIN_FILENO is repeated to avoid
140 * writing to pdes[1], which might corrupt the
141 * parent's copy. This isn't good enough in
142 * general, since the _exit() is no return, so
143 * the compiler is free to corrupt all the local
147 (void)_close(pdes[0]);
148 if (pdes[1] != STDOUT_FILENO) {
149 (void)_dup2(pdes[1], STDOUT_FILENO);
151 (void)_close(pdes[1]);
153 (void)_dup2(STDOUT_FILENO, STDIN_FILENO);
154 } else if (twoway && (pdes[1] != STDIN_FILENO)) {
155 (void)_dup2(pdes[1], STDIN_FILENO);
157 (void)_fcntl(pdes[1], F_SETFD, 0);
159 (void)_fcntl(pdes[1], F_SETFD, 0);
161 if (pdes[0] != STDIN_FILENO) {
162 (void)_dup2(pdes[0], STDIN_FILENO);
164 (void)_close(pdes[0]);
166 (void)_fcntl(pdes[0], F_SETFD, 0);
168 (void)_close(pdes[1]);
170 SLIST_FOREACH(p, &pidlist, next)
171 (void)_close(fileno(p->fp));
172 _execve(_PATH_BSHELL, argv, environ);
179 (void)_close(pdes_unused_in_parent);
181 /* Link into list of file descriptors. */
185 SLIST_INSERT_HEAD(&pidlist, cur, next);
193 * Pclose returns -1 if stream is not associated with a `popened' command,
194 * if already `pclosed', or waitpid returns an error.
200 struct pid *cur, *last = NULL;
205 * Find the appropriate file pointer and remove it from the list.
208 SLIST_FOREACH(cur, &pidlist, next) {
218 SLIST_REMOVE_HEAD(&pidlist, next);
220 SLIST_REMOVE_AFTER(last, next);
226 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
227 } while (pid == -1 && errno == EINTR);
231 return (pid == -1 ? -1 : pstat);