1/*
2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software written by Ken Arnold and
6 * published in UNIX Review, Vol. 6, No. 8.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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.
23 *
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
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/param.h>
42#include <sys/wait.h>
43#include <sys/socket.h>
44
45#include <signal.h>
46#include <errno.h>
47#include <unistd.h>
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#include <paths.h>
52
53static struct pid {
54 struct pid *next;
55 FILE *fp;
56 pid_t pid;
57} *pidlist;
58
59FILE *
60popen(command, type)
61 const char *command, *type;
62{
63 struct pid *cur;
64 FILE *iop;
65 int pdes[2], pid, twoway;
66
67 /*
68 * Lite2 introduced two-way popen() pipes using socketpair().
69 * FreeBSD's pipe() is bidirectional, so we use that.
70 */
71 if (strchr(type, '+')) {
72 twoway = 1;
73 type = "r+";
74 } else {
75 twoway = 0;
76 if (*type != 'r' && *type != 'w' || type[1])
77 return (NULL);
78 }
79 if (pipe(pdes) < 0)
80 return (NULL);
81
82 if ((cur = malloc(sizeof(struct pid))) == NULL)
83 return (NULL);
84
85 switch (pid = vfork()) {
86 case -1: /* Error. */
87 (void)close(pdes[0]);
88 (void)close(pdes[1]);
89 free(cur);
90 return (NULL);
91 /* NOTREACHED */
92 case 0: /* Child. */
93 if (*type == 'r') {
94 if (pdes[1] != STDOUT_FILENO) {
95 (void)dup2(pdes[1], STDOUT_FILENO);
96 (void)close(pdes[1]);
97 pdes[1] = STDOUT_FILENO;
98 }
99 (void) close(pdes[0]);
100 if (twoway && (pdes[1] != STDIN_FILENO))
101 (void)dup2(pdes[1], STDIN_FILENO);
102 } else {
103 if (pdes[0] != STDIN_FILENO) {
104 (void)dup2(pdes[0], STDIN_FILENO);
105 (void)close(pdes[0]);
106 }
107 (void)close(pdes[1]);
108 }
109 execl(_PATH_BSHELL, "sh", "-c", command, NULL);
110 _exit(127);
111 /* NOTREACHED */
112 }
113
114 /* Parent; assume fdopen can't fail. */
115 if (*type == 'r') {
116 iop = fdopen(pdes[0], type);
117 (void)close(pdes[1]);
118 } else {
119 iop = fdopen(pdes[1], type);
120 (void)close(pdes[0]);
121 }
122
123 /* Link into list of file descriptors. */
124 cur->fp = iop;
125 cur->pid = pid;
126 cur->next = pidlist;
127 pidlist = cur;
128
129 return (iop);
130}
131
132/*
133 * pclose --
134 * Pclose returns -1 if stream is not associated with a `popened' command,
135 * if already `pclosed', or waitpid returns an error.
136 */
137int
138pclose(iop)
139 FILE *iop;
140{
141 register struct pid *cur, *last;
142 int omask;
143 int pstat;
144 pid_t pid;
145
146 /* Find the appropriate file pointer. */
147 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
148 if (cur->fp == iop)
149 break;
150 if (cur == NULL)
151 return (-1);
152
153 (void)fclose(iop);
154
155 do {
156 pid = waitpid(cur->pid, &pstat, 0);
157 } while (pid == -1 && errno == EINTR);
158
159 /* Remove the entry from the linked list. */
160 if (last == NULL)
161 pidlist = cur->next;
162 else
163 last->next = cur->next;
164 free(cur);
165
166 return (pid == -1 ? -1 : pstat);
167}