1 /* $NetBSD: popenve.c,v 1.2 2025/02/11 17:48:30 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 #ifdef HAVE_SYS_CDEFS_H
40 #include <sys/cdefs.h>
41 #endif
42 #if defined(LIBC_SCCS) && !defined(lint)
43 #if 0
44 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
45 #else
46 __RCSID("$NetBSD: popenve.c,v 1.2 2025/02/11 17:48:30 christos Exp $");
47 #endif
48 #endif /* LIBC_SCCS and not lint */
49
50 #include <sys/param.h>
51 #include <sys/wait.h>
52 #include <sys/socket.h>
53
54 #include <assert.h>
55 #include <errno.h>
56 #include <paths.h>
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 #include <fcntl.h>
63
64 #ifdef __weak_alias
65 __weak_alias(popen,_popen)
66 __weak_alias(pclose,_pclose)
67 #endif
68
69 static struct pid {
70 struct pid *next;
71 FILE *fp;
72 #ifdef _REENTRANT
73 int fd;
74 #endif
75 pid_t pid;
76 } *pidlist;
77
78 #ifdef _REENTRANT
79 static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
80 #endif
81
82 static struct pid *
pdes_get(int * pdes,const char ** type)83 pdes_get(int *pdes, const char **type)
84 {
85 struct pid *cur;
86 int flags = strchr(*type, 'e') ? O_CLOEXEC : 0;
87 int serrno;
88
89 if (strchr(*type, '+')) {
90 #ifndef SOCK_CLOEXEC
91 #define SOCK_CLOEXEC 0
92 #endif
93 int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
94 *type = "r+";
95 if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
96 return NULL;
97 #if SOCK_CLOEXEC == 0
98 fcntl(pdes[0], F_SETFD, FD_CLOEXEC);
99 fcntl(pdes[1], F_SETFD, FD_CLOEXEC);
100 #endif
101 } else {
102 *type = strrchr(*type, 'r') ? "r" : "w";
103 #if SOCK_CLOEXEC != 0
104 if (pipe2(pdes, flags) == -1)
105 return NULL;
106 #else
107 if (pipe(pdes) == -1)
108 return NULL;
109 fcntl(pdes[0], F_SETFL, fcntl(pdes[0], F_GETFL) | flags);
110 fcntl(pdes[1], F_SETFL, fcntl(pdes[1], F_GETFL) | flags);
111 #endif
112 }
113
114 if ((cur = malloc(sizeof(*cur))) != NULL)
115 return cur;
116 serrno = errno;
117 (void)close(pdes[0]);
118 (void)close(pdes[1]);
119 errno = serrno;
120 return NULL;
121 }
122
123 static void
pdes_child(int * pdes,const char * type)124 pdes_child(int *pdes, const char *type)
125 {
126 struct pid *old;
127
128 /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
129 from previous popen() calls that remain open in the
130 parent process are closed in the new child process. */
131 for (old = pidlist; old; old = old->next)
132 #ifdef _REENTRANT
133 (void)close(old->fd); /* don't allow a flush */
134 #else
135 (void)close(fileno(old->fp)); /* don't allow a flush */
136 #endif
137
138 if (type[0] == 'r') {
139 (void)close(pdes[0]);
140 if (pdes[1] != STDOUT_FILENO) {
141 (void)dup2(pdes[1], STDOUT_FILENO);
142 (void)close(pdes[1]);
143 }
144 if (type[1] == '+')
145 (void)dup2(STDOUT_FILENO, STDIN_FILENO);
146 } else {
147 (void)close(pdes[1]);
148 if (pdes[0] != STDIN_FILENO) {
149 (void)dup2(pdes[0], STDIN_FILENO);
150 (void)close(pdes[0]);
151 }
152 }
153 }
154
155 static void
pdes_parent(int * pdes,struct pid * cur,pid_t pid,const char * type)156 pdes_parent(int *pdes, struct pid *cur, pid_t pid, const char *type)
157 {
158 FILE *iop;
159
160 /* Parent; assume fdopen can't fail. */
161 if (*type == 'r') {
162 iop = fdopen(pdes[0], type);
163 #ifdef _REENTRANT
164 cur->fd = pdes[0];
165 #endif
166 (void)close(pdes[1]);
167 } else {
168 iop = fdopen(pdes[1], type);
169 #ifdef _REENTRANT
170 cur->fd = pdes[1];
171 #endif
172 (void)close(pdes[0]);
173 }
174
175 /* Link into list of file descriptors. */
176 cur->fp = iop;
177 cur->pid = pid;
178 cur->next = pidlist;
179 pidlist = cur;
180 }
181
182 static void
pdes_error(int * pdes,struct pid * cur)183 pdes_error(int *pdes, struct pid *cur)
184 {
185 free(cur);
186 (void)close(pdes[0]);
187 (void)close(pdes[1]);
188 }
189
190 FILE *
popenve(const char * cmd,char * const * argv,char * const * envp,const char * type)191 popenve(const char *cmd, char *const *argv, char *const *envp, const char *type)
192 {
193 struct pid *cur;
194 int pdes[2], serrno;
195 pid_t pid;
196
197 if ((cur = pdes_get(pdes, &type)) == NULL)
198 return NULL;
199
200 #ifdef _REENTRANT
201 (void)rwlock_rdlock(&pidlist_lock);
202 #endif
203 switch (pid = vfork()) {
204 case -1: /* Error. */
205 serrno = errno;
206 #ifdef _REENTRANT
207 (void)rwlock_unlock(&pidlist_lock);
208 #endif
209 pdes_error(pdes, cur);
210 errno = serrno;
211 return NULL;
212 /* NOTREACHED */
213 case 0: /* Child. */
214 pdes_child(pdes, type);
215 execve(cmd, argv, envp);
216 _exit(127);
217 /* NOTREACHED */
218 }
219
220 pdes_parent(pdes, cur, pid, type);
221
222 #ifdef _REENTRANT
223 (void)rwlock_unlock(&pidlist_lock);
224 #endif
225
226 return cur->fp;
227 }
228
229 /*
230 * pclose --
231 * Pclose returns -1 if stream is not associated with a `popened' command,
232 * if already `pclosed', or waitpid returns an error.
233 */
234 int
pcloseve(FILE * iop)235 pcloseve(FILE *iop)
236 {
237 struct pid *cur, *last;
238 int pstat;
239 pid_t pid;
240
241 #ifdef _REENTRANT
242 rwlock_wrlock(&pidlist_lock);
243 #endif
244
245 /* Find the appropriate file pointer. */
246 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
247 if (cur->fp == iop)
248 break;
249 if (cur == NULL) {
250 #ifdef _REENTRANT
251 (void)rwlock_unlock(&pidlist_lock);
252 #endif
253 errno = ESRCH;
254 return -1;
255 }
256
257 (void)fclose(iop);
258
259 /* Remove the entry from the linked list. */
260 if (last == NULL)
261 pidlist = cur->next;
262 else
263 last->next = cur->next;
264
265 #ifdef _REENTRANT
266 (void)rwlock_unlock(&pidlist_lock);
267 #endif
268
269 do {
270 pid = waitpid(cur->pid, &pstat, 0);
271 } while (pid == -1 && errno == EINTR);
272
273 free(cur);
274
275 return pid == -1 ? -1 : pstat;
276 }
277