1 /* $NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software written by Ken Arnold and
8 * published in UNIX Review, Vol. 6, No. 8.
9 *
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.
21 *
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.
33 */
34
35 #ifdef HAVE_CONFIG_H
36 #include "config.h"
37 #endif
38
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 #if 0
42 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
43 #else
44 __RCSID("$NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $");
45 #endif
46 #endif /* LIBC_SCCS and not lint */
47
48 #include <sys/param.h>
49 #include <sys/wait.h>
50 #include <sys/socket.h>
51
52 #include <assert.h>
53 #include <errno.h>
54 #include <paths.h>
55 #include <signal.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 #include <fcntl.h>
61
62 #ifdef __weak_alias
63 __weak_alias(popen,_popen)
64 __weak_alias(pclose,_pclose)
65 #endif
66
67 static struct pid {
68 struct pid *next;
69 FILE *fp;
70 #ifdef _REENTRANT
71 int fd;
72 #endif
73 pid_t pid;
74 } *pidlist;
75
76 #ifdef _REENTRANT
77 static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
78 #endif
79
80 static struct pid *
pdes_get(int * pdes,const char ** type)81 pdes_get(int *pdes, const char **type)
82 {
83 struct pid *cur;
84 int flags = strchr(*type, 'e') ? O_CLOEXEC : 0;
85 int serrno;
86
87 if (strchr(*type, '+')) {
88 #ifndef SOCK_CLOEXEC
89 #define SOCK_CLOEXEC 0
90 #endif
91 int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
92 *type = "r+";
93 if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
94 return NULL;
95 #if SOCK_CLOEXEC == 0
96 fcntl(pdes[0], F_SETFD, FD_CLOEXEC);
97 fcntl(pdes[1], F_SETFD, FD_CLOEXEC);
98 #endif
99 } else {
100 *type = strrchr(*type, 'r') ? "r" : "w";
101 #if SOCK_CLOEXEC != 0
102 if (pipe2(pdes, flags) == -1)
103 return NULL;
104 #else
105 if (pipe(pdes) == -1)
106 return NULL;
107 fcntl(pdes[0], F_SETFL, fcntl(pdes[0], F_GETFL) | flags);
108 fcntl(pdes[1], F_SETFL, fcntl(pdes[1], F_GETFL) | flags);
109 #endif
110 }
111
112 if ((cur = malloc(sizeof(*cur))) != NULL)
113 return cur;
114 serrno = errno;
115 (void)close(pdes[0]);
116 (void)close(pdes[1]);
117 errno = serrno;
118 return NULL;
119 }
120
121 static void
pdes_child(int * pdes,const char * type)122 pdes_child(int *pdes, const char *type)
123 {
124 struct pid *old;
125
126 /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
127 from previous popen() calls that remain open in the
128 parent process are closed in the new child process. */
129 for (old = pidlist; old; old = old->next)
130 #ifdef _REENTRANT
131 (void)close(old->fd); /* don't allow a flush */
132 #else
133 (void)close(fileno(old->fp)); /* don't allow a flush */
134 #endif
135
136 if (type[0] == 'r') {
137 (void)close(pdes[0]);
138 if (pdes[1] != STDOUT_FILENO) {
139 (void)dup2(pdes[1], STDOUT_FILENO);
140 (void)close(pdes[1]);
141 }
142 if (type[1] == '+')
143 (void)dup2(STDOUT_FILENO, STDIN_FILENO);
144 } else {
145 (void)close(pdes[1]);
146 if (pdes[0] != STDIN_FILENO) {
147 (void)dup2(pdes[0], STDIN_FILENO);
148 (void)close(pdes[0]);
149 }
150 }
151 }
152
153 static void
pdes_parent(int * pdes,struct pid * cur,pid_t pid,const char * type)154 pdes_parent(int *pdes, struct pid *cur, pid_t pid, const char *type)
155 {
156 FILE *iop;
157
158 /* Parent; assume fdopen can't fail. */
159 if (*type == 'r') {
160 iop = fdopen(pdes[0], type);
161 #ifdef _REENTRANT
162 cur->fd = pdes[0];
163 #endif
164 (void)close(pdes[1]);
165 } else {
166 iop = fdopen(pdes[1], type);
167 #ifdef _REENTRANT
168 cur->fd = pdes[1];
169 #endif
170 (void)close(pdes[0]);
171 }
172
173 /* Link into list of file descriptors. */
174 cur->fp = iop;
175 cur->pid = pid;
176 cur->next = pidlist;
177 pidlist = cur;
178 }
179
180 static void
pdes_error(int * pdes,struct pid * cur)181 pdes_error(int *pdes, struct pid *cur)
182 {
183 free(cur);
184 (void)close(pdes[0]);
185 (void)close(pdes[1]);
186 }
187
188 FILE *
popenve(const char * cmd,char * const * argv,char * const * envp,const char * type)189 popenve(const char *cmd, char *const *argv, char *const *envp, const char *type)
190 {
191 struct pid *cur;
192 int pdes[2], serrno;
193 pid_t pid;
194
195 if ((cur = pdes_get(pdes, &type)) == NULL)
196 return NULL;
197
198 #ifdef _REENTRANT
199 (void)rwlock_rdlock(&pidlist_lock);
200 #endif
201 switch (pid = vfork()) {
202 case -1: /* Error. */
203 serrno = errno;
204 #ifdef _REENTRANT
205 (void)rwlock_unlock(&pidlist_lock);
206 #endif
207 pdes_error(pdes, cur);
208 errno = serrno;
209 return NULL;
210 /* NOTREACHED */
211 case 0: /* Child. */
212 pdes_child(pdes, type);
213 execve(cmd, argv, envp);
214 _exit(127);
215 /* NOTREACHED */
216 }
217
218 pdes_parent(pdes, cur, pid, type);
219
220 #ifdef _REENTRANT
221 (void)rwlock_unlock(&pidlist_lock);
222 #endif
223
224 return cur->fp;
225 }
226
227 /*
228 * pclose --
229 * Pclose returns -1 if stream is not associated with a `popened' command,
230 * if already `pclosed', or waitpid returns an error.
231 */
232 int
pcloseve(FILE * iop)233 pcloseve(FILE *iop)
234 {
235 struct pid *cur, *last;
236 int pstat;
237 pid_t pid;
238
239 #ifdef _REENTRANT
240 rwlock_wrlock(&pidlist_lock);
241 #endif
242
243 /* Find the appropriate file pointer. */
244 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
245 if (cur->fp == iop)
246 break;
247 if (cur == NULL) {
248 #ifdef _REENTRANT
249 (void)rwlock_unlock(&pidlist_lock);
250 #endif
251 errno = ESRCH;
252 return -1;
253 }
254
255 (void)fclose(iop);
256
257 /* Remove the entry from the linked list. */
258 if (last == NULL)
259 pidlist = cur->next;
260 else
261 last->next = cur->next;
262
263 #ifdef _REENTRANT
264 (void)rwlock_unlock(&pidlist_lock);
265 #endif
266
267 do {
268 pid = waitpid(cur->pid, &pstat, 0);
269 } while (pid == -1 && errno == EINTR);
270
271 free(cur);
272
273 return pid == -1 ? -1 : pstat;
274 }
275