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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <sys/param.h> 41 #include <sys/queue.h> 42 #include <sys/wait.h> 43 44 #include <signal.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <unistd.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <paths.h> 52 #include <pthread.h> 53 #include "un-namespace.h" 54 #include "libc_private.h" 55 56 extern char **environ; 57 58 struct pid { 59 SLIST_ENTRY(pid) next; 60 FILE *fp; 61 pid_t pid; 62 }; 63 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist); 64 static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER; 65 66 #define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex) 67 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex) 68 69 FILE * 70 popen(command, type) 71 const char *command, *type; 72 { 73 struct pid *cur; 74 FILE *iop; 75 int pdes[2], pid, twoway, cloexec; 76 char *argv[4]; 77 struct pid *p; 78 79 cloexec = strchr(type, 'e') != NULL; 80 /* 81 * Lite2 introduced two-way popen() pipes using _socketpair(). 82 * FreeBSD's pipe() is bidirectional, so we use that. 83 */ 84 if (strchr(type, '+')) { 85 twoway = 1; 86 type = "r+"; 87 } else { 88 twoway = 0; 89 if ((*type != 'r' && *type != 'w') || 90 (type[1] && (type[1] != 'e' || type[2]))) 91 return (NULL); 92 } 93 if (pipe2(pdes, O_CLOEXEC) < 0) 94 return (NULL); 95 96 if ((cur = malloc(sizeof(struct pid))) == NULL) { 97 (void)_close(pdes[0]); 98 (void)_close(pdes[1]); 99 return (NULL); 100 } 101 102 argv[0] = "sh"; 103 argv[1] = "-c"; 104 argv[2] = (char *)command; 105 argv[3] = NULL; 106 107 THREAD_LOCK(); 108 switch (pid = vfork()) { 109 case -1: /* Error. */ 110 THREAD_UNLOCK(); 111 (void)_close(pdes[0]); 112 (void)_close(pdes[1]); 113 free(cur); 114 return (NULL); 115 /* NOTREACHED */ 116 case 0: /* Child. */ 117 if (*type == 'r') { 118 /* 119 * The _dup2() to STDIN_FILENO is repeated to avoid 120 * writing to pdes[1], which might corrupt the 121 * parent's copy. This isn't good enough in 122 * general, since the _exit() is no return, so 123 * the compiler is free to corrupt all the local 124 * variables. 125 */ 126 if (pdes[1] != STDOUT_FILENO) { 127 (void)_dup2(pdes[1], STDOUT_FILENO); 128 if (twoway) 129 (void)_dup2(STDOUT_FILENO, STDIN_FILENO); 130 } else if (twoway && (pdes[1] != STDIN_FILENO)) { 131 (void)_dup2(pdes[1], STDIN_FILENO); 132 (void)_fcntl(pdes[1], F_SETFD, 0); 133 } else 134 (void)_fcntl(pdes[1], F_SETFD, 0); 135 } else { 136 if (pdes[0] != STDIN_FILENO) { 137 (void)_dup2(pdes[0], STDIN_FILENO); 138 } else 139 (void)_fcntl(pdes[0], F_SETFD, 0); 140 } 141 SLIST_FOREACH(p, &pidlist, next) 142 (void)_close(fileno(p->fp)); 143 _execve(_PATH_BSHELL, argv, environ); 144 _exit(127); 145 /* NOTREACHED */ 146 } 147 THREAD_UNLOCK(); 148 149 /* Parent; assume fdopen can't fail. */ 150 if (*type == 'r') { 151 iop = fdopen(pdes[0], type); 152 (void)_close(pdes[1]); 153 } else { 154 iop = fdopen(pdes[1], type); 155 (void)_close(pdes[0]); 156 } 157 158 /* Link into list of file descriptors. */ 159 cur->fp = iop; 160 cur->pid = pid; 161 THREAD_LOCK(); 162 SLIST_INSERT_HEAD(&pidlist, cur, next); 163 THREAD_UNLOCK(); 164 165 /* 166 * To guard against undesired fd passing with concurrent calls, 167 * only clear the close-on-exec flag after linking the file into 168 * the list which will cause an explicit close. 169 */ 170 if (!cloexec) 171 (void)_fcntl(*type == 'r' ? pdes[0] : pdes[1], F_SETFD, 0); 172 173 return (iop); 174 } 175 176 /* 177 * pclose -- 178 * Pclose returns -1 if stream is not associated with a `popened' command, 179 * if already `pclosed', or waitpid returns an error. 180 */ 181 int 182 pclose(iop) 183 FILE *iop; 184 { 185 struct pid *cur, *last = NULL; 186 int pstat; 187 pid_t pid; 188 189 /* 190 * Find the appropriate file pointer and remove it from the list. 191 */ 192 THREAD_LOCK(); 193 SLIST_FOREACH(cur, &pidlist, next) { 194 if (cur->fp == iop) 195 break; 196 last = cur; 197 } 198 if (cur == NULL) { 199 THREAD_UNLOCK(); 200 return (-1); 201 } 202 if (last == NULL) 203 SLIST_REMOVE_HEAD(&pidlist, next); 204 else 205 SLIST_REMOVE_AFTER(last, next); 206 THREAD_UNLOCK(); 207 208 (void)fclose(iop); 209 210 do { 211 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 212 } while (pid == -1 && errno == EINTR); 213 214 free(cur); 215 216 return (pid == -1 ? -1 : pstat); 217 } 218