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 8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/param.h>
42#include <sys/wait.h>
43
44#include <signal.h>
45#include <errno.h>
46#include <unistd.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <paths.h>
51
52static struct pid {
53 struct pid *next;
54 FILE *fp;
55 pid_t pid;
56} *pidlist;
57
58FILE *
59popen(program, type)
60 const char *program;
61 const char *type;
62{
63 struct pid *cur;
64 FILE *iop;
65 int pdes[2], pid;
66
67 if ( (*type != 'r' && *type != 'w') || type[1])
68 return (NULL);
69
70 if ((cur = malloc(sizeof(struct pid))) == NULL)
71 return (NULL);
72
73 if (pipe(pdes) < 0) {
74 free(cur);
75 return (NULL);
76 }
77
78 switch (pid = vfork()) {
79 case -1: /* Error. */
80 (void)close(pdes[0]);
81 (void)close(pdes[1]);
82 free(cur);
83 return (NULL);
84 /* NOTREACHED */
85 case 0: /* Child. */
86 if (*type == 'r') {
87 if (pdes[1] != STDOUT_FILENO) {
88 (void)dup2(pdes[1], STDOUT_FILENO);
89 (void)close(pdes[1]);
90 }
91 (void) close(pdes[0]);
92 } else {
93 if (pdes[0] != STDIN_FILENO) {
94 (void)dup2(pdes[0], STDIN_FILENO);
95 (void)close(pdes[0]);
96 }
97 (void)close(pdes[1]);
98 }
99 execl(_PATH_BSHELL, "sh", "-c", program, NULL);
100 _exit(127);
101 /* NOTREACHED */
102 }
103
104 /* Parent; assume fdopen can't fail. */
105 if (*type == 'r') {
106 iop = fdopen(pdes[0], type);
107 (void)close(pdes[1]);
108 } else {
109 iop = fdopen(pdes[1], type);
110 (void)close(pdes[0]);
111 }
112
113 /* Link into list of file descriptors. */
114 cur->fp = iop;
115 cur->pid = pid;
116 cur->next = pidlist;
117 pidlist = cur;
118
119 return (iop);
120}
121
122/*
123 * pclose --
124 * Pclose returns -1 if stream is not associated with a `popened' command,
125 * if already `pclosed', or waitpid returns an error.
126 */
127int
128pclose(iop)
129 FILE *iop;
130{
131 register struct pid *cur, *last;
132 int omask;
133 union wait pstat;
134 pid_t pid;
135
136 (void)fclose(iop);
137
138 /* Find the appropriate file pointer. */
139 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
140 if (cur->fp == iop)
141 break;
142 if (cur == NULL)
143 return (-1);
144
145 /* Get the status of the process. */
146 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
147 do {
148 pid = waitpid(cur->pid, (int *) &pstat, 0);
149 } while (pid == -1 && errno == EINTR);
150 (void)sigsetmask(omask);
151
152 /* Remove the entry from the linked list. */
153 if (last == NULL)
154 pidlist = cur->next;
155 else
156 last->next = cur->next;
157 free(cur);
158
159 return (pid == -1 ? -1 : pstat.w_status);
160}