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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * $FreeBSD: src/lib/libc/gen/popen.c,v 1.14 2000/01/27 23:06:19 jasone Exp $
37 * $DragonFly: src/lib/libc/gen/popen.c,v 1.6 2005/11/13 00:07:42 swildner Exp $
39 * @(#)popen.c 8.3 (Berkeley) 5/3/95
42 #include "namespace.h"
43 #include <sys/param.h>
53 #include "un-namespace.h"
55 extern char **environ;
64 popen(const char *command, const char *type)
68 int pdes[2], pid, twoway;
73 * Lite2 introduced two-way popen() pipes using _socketpair().
74 * FreeBSD's pipe() is bidirectional, so we use that.
76 if (strchr(type, '+')) {
81 if ((*type != 'r' && *type != 'w') || type[1])
87 if ((cur = malloc(sizeof(struct pid))) == NULL) {
98 switch (pid = fork()) {
108 * The _dup2() to STDIN_FILENO is repeated to avoid
109 * writing to pdes[1], which might corrupt the
110 * parent's copy. This isn't good enough in
111 * general, since the _exit() is no return, so
112 * the compiler is free to corrupt all the local
116 if (pdes[1] != STDOUT_FILENO) {
117 _dup2(pdes[1], STDOUT_FILENO);
120 _dup2(STDOUT_FILENO, STDIN_FILENO);
121 } else if (twoway && (pdes[1] != STDIN_FILENO))
122 _dup2(pdes[1], STDIN_FILENO);
124 if (pdes[0] != STDIN_FILENO) {
125 _dup2(pdes[0], STDIN_FILENO);
130 for (p = pidlist; p; p = p->next) {
131 _close(fileno(p->fp));
133 _execve(_PATH_BSHELL, __DECONST(char * const *, argv), environ);
138 /* Parent; assume fdopen can't fail. */
140 iop = fdopen(pdes[0], type);
143 iop = fdopen(pdes[1], type);
147 /* Link into list of file descriptors. */
158 * Pclose returns -1 if stream is not associated with a `popened' command,
159 * if already `pclosed', or waitpid returns an error.
164 struct pid *cur, *last;
168 /* Find the appropriate file pointer. */
169 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
178 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
179 } while (pid == -1 && errno == EINTR);
181 /* Remove the entry from the linked list. */
185 last->next = cur->next;
188 return (pid == -1 ? -1 : pstat);