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 * 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 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 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 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 * 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 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