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 1.4 2005/01/31 22:29:15 dillon 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;
65 const char *command, *type;
69 int pdes[2], pid, twoway;
74 * Lite2 introduced two-way popen() pipes using _socketpair().
75 * FreeBSD's pipe() is bidirectional, so we use that.
77 if (strchr(type, '+')) {
82 if ((*type != 'r' && *type != 'w') || type[1])
88 if ((cur = malloc(sizeof(struct pid))) == NULL) {
89 (void)_close(pdes[0]);
90 (void)_close(pdes[1]);
96 argv[2] = (char *)command;
99 switch (pid = vfork()) {
100 case -1: /* Error. */
101 (void)_close(pdes[0]);
102 (void)_close(pdes[1]);
109 * The _dup2() to STDIN_FILENO is repeated to avoid
110 * writing to pdes[1], which might corrupt the
111 * parent's copy. This isn't good enough in
112 * general, since the _exit() is no return, so
113 * the compiler is free to corrupt all the local
116 (void)_close(pdes[0]);
117 if (pdes[1] != STDOUT_FILENO) {
118 (void)_dup2(pdes[1], STDOUT_FILENO);
119 (void)_close(pdes[1]);
121 (void)_dup2(STDOUT_FILENO, STDIN_FILENO);
122 } else if (twoway && (pdes[1] != STDIN_FILENO))
123 (void)_dup2(pdes[1], STDIN_FILENO);
125 if (pdes[0] != STDIN_FILENO) {
126 (void)_dup2(pdes[0], STDIN_FILENO);
127 (void)_close(pdes[0]);
129 (void)_close(pdes[1]);
131 for (p = pidlist; p; p = p->next) {
132 (void)_close(fileno(p->fp));
134 _execve(_PATH_BSHELL, argv, environ);
139 /* Parent; assume fdopen can't fail. */
141 iop = fdopen(pdes[0], type);
142 (void)_close(pdes[1]);
144 iop = fdopen(pdes[1], type);
145 (void)_close(pdes[0]);
148 /* Link into list of file descriptors. */
159 * Pclose returns -1 if stream is not associated with a `popened' command,
160 * if already `pclosed', or waitpid returns an error.
166 struct pid *cur, *last;
171 /* Find the appropriate file pointer. */
172 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
181 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
182 } while (pid == -1 && errno == EINTR);
184 /* Remove the entry from the linked list. */
188 last->next = cur->next;
191 return (pid == -1 ? -1 : pstat);