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(const char *command, const char *type) 71 { 72 struct pid *cur; 73 FILE *iop; 74 int pdes[2], pid, twoway, cloexec; 75 char *argv[4]; 76 struct pid *p; 77 78 cloexec = strchr(type, 'e') != NULL; 79 /* 80 * Lite2 introduced two-way popen() pipes using _socketpair(). 81 * FreeBSD's pipe() is bidirectional, so we use that. 82 */ 83 if (strchr(type, '+')) { 84 twoway = 1; 85 type = "r+"; 86 } else { 87 twoway = 0; 88 if ((*type != 'r' && *type != 'w') || 89 (type[1] && (type[1] != 'e' || type[2]))) 90 return (NULL); 91 } 92 if (pipe2(pdes, O_CLOEXEC) < 0) 93 return (NULL); 94 95 if ((cur = malloc(sizeof(struct pid))) == NULL) { 96 (void)_close(pdes[0]); 97 (void)_close(pdes[1]); 98 return (NULL); 99 } 100 101 argv[0] = "sh"; 102 argv[1] = "-c"; 103 argv[2] = (char *)command; 104 argv[3] = NULL; 105 106 THREAD_LOCK(); 107 switch (pid = vfork()) { 108 case -1: /* Error. */ 109 THREAD_UNLOCK(); 110 (void)_close(pdes[0]); 111 (void)_close(pdes[1]); 112 free(cur); 113 return (NULL); 114 /* NOTREACHED */ 115 case 0: /* Child. */ 116 if (*type == 'r') { 117 /* 118 * The _dup2() to STDIN_FILENO is repeated to avoid 119 * writing to pdes[1], which might corrupt the 120 * parent's copy. This isn't good enough in 121 * general, since the _exit() is no return, so 122 * the compiler is free to corrupt all the local 123 * variables. 124 */ 125 if (pdes[1] != STDOUT_FILENO) { 126 (void)_dup2(pdes[1], STDOUT_FILENO); 127 if (twoway) 128 (void)_dup2(STDOUT_FILENO, STDIN_FILENO); 129 } else if (twoway && (pdes[1] != STDIN_FILENO)) { 130 (void)_dup2(pdes[1], STDIN_FILENO); 131 (void)_fcntl(pdes[1], F_SETFD, 0); 132 } else 133 (void)_fcntl(pdes[1], F_SETFD, 0); 134 } else { 135 if (pdes[0] != STDIN_FILENO) { 136 (void)_dup2(pdes[0], STDIN_FILENO); 137 } else 138 (void)_fcntl(pdes[0], F_SETFD, 0); 139 } 140 SLIST_FOREACH(p, &pidlist, next) 141 (void)_close(fileno(p->fp)); 142 _execve(_PATH_BSHELL, argv, environ); 143 _exit(127); 144 /* NOTREACHED */ 145 } 146 THREAD_UNLOCK(); 147 148 /* Parent; assume fdopen can't fail. */ 149 if (*type == 'r') { 150 iop = fdopen(pdes[0], type); 151 (void)_close(pdes[1]); 152 } else { 153 iop = fdopen(pdes[1], type); 154 (void)_close(pdes[0]); 155 } 156 157 /* Link into list of file descriptors. */ 158 cur->fp = iop; 159 cur->pid = pid; 160 THREAD_LOCK(); 161 SLIST_INSERT_HEAD(&pidlist, cur, next); 162 THREAD_UNLOCK(); 163 164 /* 165 * To guard against undesired fd passing with concurrent calls, 166 * only clear the close-on-exec flag after linking the file into 167 * the list which will cause an explicit close. 168 */ 169 if (!cloexec) 170 (void)_fcntl(*type == 'r' ? pdes[0] : pdes[1], F_SETFD, 0); 171 172 return (iop); 173 } 174 175 /* 176 * pclose -- 177 * Pclose returns -1 if stream is not associated with a `popened' command, 178 * if already `pclosed', or waitpid returns an error. 179 */ 180 int 181 pclose(FILE *iop) 182 { 183 struct pid *cur, *last = NULL; 184 int pstat; 185 pid_t pid; 186 187 /* 188 * Find the appropriate file pointer and remove it from the list. 189 */ 190 THREAD_LOCK(); 191 SLIST_FOREACH(cur, &pidlist, next) { 192 if (cur->fp == iop) 193 break; 194 last = cur; 195 } 196 if (cur == NULL) { 197 THREAD_UNLOCK(); 198 return (-1); 199 } 200 if (last == NULL) 201 SLIST_REMOVE_HEAD(&pidlist, next); 202 else 203 SLIST_REMOVE_AFTER(last, next); 204 THREAD_UNLOCK(); 205 206 (void)fclose(iop); 207 208 do { 209 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 210 } while (pid == -1 && errno == EINTR); 211 212 free(cur); 213 214 return (pid == -1 ? -1 : pstat); 215 } 216