kernel, libc: signals fixes
[minix.git] / lib / libc / gen / popen.c
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1 /* $NetBSD: popen.c,v 1.32 2012/06/25 22:32:43 abs Exp $ */
3 /*
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software written by Ken Arnold and
8 * published in UNIX Review, Vol. 6, No. 8.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
39 #else
40 __RCSID("$NetBSD: popen.c,v 1.32 2012/06/25 22:32:43 abs Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
44 #include "namespace.h"
45 #include <sys/param.h>
46 #include <sys/wait.h>
47 #include <sys/socket.h>
49 #include <assert.h>
50 #include <errno.h>
51 #include <paths.h>
52 #include <signal.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57 #include <fcntl.h>
59 #include "env.h"
60 #include "reentrant.h"
62 #if defined(__minix) && !defined(O_CLOEXEC)
63 #define O_CLOEXEC 0
64 #endif
66 #ifdef __weak_alias
67 __weak_alias(popen,_popen)
68 __weak_alias(pclose,_pclose)
69 #endif
71 static struct pid {
72 struct pid *next;
73 FILE *fp;
74 #ifdef _REENTRANT
75 int fd;
76 #endif
77 pid_t pid;
78 } *pidlist;
80 #ifdef _REENTRANT
81 static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
82 #endif
84 FILE *
85 popen(const char *command, const char *type)
87 struct pid *cur, *old;
88 FILE *iop;
89 const char * volatile xtype = type;
90 int pdes[2], pid, serrno;
91 volatile int twoway;
92 int flags;
94 _DIAGASSERT(command != NULL);
95 _DIAGASSERT(xtype != NULL);
97 flags = strchr(xtype, 'e') ? O_CLOEXEC : 0;
98 if (strchr(xtype, '+')) {
99 int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
100 twoway = 1;
101 xtype = "r+";
102 if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
103 return NULL;
104 } else {
105 twoway = 0;
106 xtype = strrchr(xtype, 'r') ? "r" : "w";
107 if (pipe2(pdes, flags) == -1)
108 return NULL;
111 if ((cur = malloc(sizeof(struct pid))) == NULL) {
112 (void)close(pdes[0]);
113 (void)close(pdes[1]);
114 errno = ENOMEM;
115 return (NULL);
118 (void)rwlock_rdlock(&pidlist_lock);
119 (void)__readlockenv();
120 switch (pid = vfork()) {
121 case -1: /* Error. */
122 serrno = errno;
123 (void)__unlockenv();
124 (void)rwlock_unlock(&pidlist_lock);
125 free(cur);
126 (void)close(pdes[0]);
127 (void)close(pdes[1]);
128 errno = serrno;
129 return (NULL);
130 /* NOTREACHED */
131 case 0: /* Child. */
132 /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
133 from previous popen() calls that remain open in the
134 parent process are closed in the new child process. */
135 for (old = pidlist; old; old = old->next)
136 #ifdef _REENTRANT
137 close(old->fd); /* don't allow a flush */
138 #else
139 close(fileno(old->fp)); /* don't allow a flush */
140 #endif
142 if (*xtype == 'r') {
143 (void)close(pdes[0]);
144 if (pdes[1] != STDOUT_FILENO) {
145 (void)dup2(pdes[1], STDOUT_FILENO);
146 (void)close(pdes[1]);
148 if (twoway)
149 (void)dup2(STDOUT_FILENO, STDIN_FILENO);
150 } else {
151 (void)close(pdes[1]);
152 if (pdes[0] != STDIN_FILENO) {
153 (void)dup2(pdes[0], STDIN_FILENO);
154 (void)close(pdes[0]);
158 execl(_PATH_BSHELL, "sh", "-c", command, NULL);
159 _exit(127);
160 /* NOTREACHED */
162 (void)__unlockenv();
164 /* Parent; assume fdopen can't fail. */
165 if (*xtype == 'r') {
166 iop = fdopen(pdes[0], xtype);
167 #ifdef _REENTRANT
168 cur->fd = pdes[0];
169 #endif
170 (void)close(pdes[1]);
171 } else {
172 iop = fdopen(pdes[1], xtype);
173 #ifdef _REENTRANT
174 cur->fd = pdes[1];
175 #endif
176 (void)close(pdes[0]);
179 /* Link into list of file descriptors. */
180 cur->fp = iop;
181 cur->pid = pid;
182 cur->next = pidlist;
183 pidlist = cur;
184 (void)rwlock_unlock(&pidlist_lock);
186 return (iop);
190 * pclose --
191 * Pclose returns -1 if stream is not associated with a `popened' command,
192 * if already `pclosed', or waitpid returns an error.
195 pclose(FILE *iop)
197 struct pid *cur, *last;
198 int pstat;
199 pid_t pid;
201 _DIAGASSERT(iop != NULL);
203 rwlock_wrlock(&pidlist_lock);
205 /* Find the appropriate file pointer. */
206 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
207 if (cur->fp == iop)
208 break;
209 if (cur == NULL) {
210 (void)rwlock_unlock(&pidlist_lock);
211 return (-1);
214 (void)fclose(iop);
216 /* Remove the entry from the linked list. */
217 if (last == NULL)
218 pidlist = cur->next;
219 else
220 last->next = cur->next;
222 (void)rwlock_unlock(&pidlist_lock);
224 do {
225 pid = waitpid(cur->pid, &pstat, 0);
226 } while (pid == -1 && errno == EINTR);
228 free(cur);
230 return (pid == -1 ? -1 : pstat);