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 <unistd.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <paths.h> 51 #include <pthread.h> 52 #include "un-namespace.h" 53 #include "libc_private.h" 54 55 extern char **environ; 56 57 struct pid { 58 SLIST_ENTRY(pid) next; 59 FILE *fp; 60 pid_t pid; 61 }; 62 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist); 63 static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER; 64 65 #define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex) 66 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex) 67 68 FILE * 69 popen(command, type) 70 const char *command, *type; 71 { 72 struct pid *cur; 73 FILE *iop; 74 int pdes[2], pid, twoway; 75 char *argv[4]; 76 struct pid *p; 77 78 /* 79 * Lite2 introduced two-way popen() pipes using _socketpair(). 80 * FreeBSD's pipe() is bidirectional, so we use that. 81 */ 82 if (strchr(type, '+')) { 83 twoway = 1; 84 type = "r+"; 85 } else { 86 twoway = 0; 87 if ((*type != 'r' && *type != 'w') || type[1]) 88 return (NULL); 89 } 90 if (pipe(pdes) < 0) 91 return (NULL); 92 93 if ((cur = malloc(sizeof(struct pid))) == NULL) { 94 (void)_close(pdes[0]); 95 (void)_close(pdes[1]); 96 return (NULL); 97 } 98 99 argv[0] = "sh"; 100 argv[1] = "-c"; 101 argv[2] = (char *)command; 102 argv[3] = NULL; 103 104 THREAD_LOCK(); 105 switch (pid = vfork()) { 106 case -1: /* Error. */ 107 THREAD_UNLOCK(); 108 (void)_close(pdes[0]); 109 (void)_close(pdes[1]); 110 free(cur); 111 return (NULL); 112 /* NOTREACHED */ 113 case 0: /* Child. */ 114 if (*type == 'r') { 115 /* 116 * The _dup2() to STDIN_FILENO is repeated to avoid 117 * writing to pdes[1], which might corrupt the 118 * parent's copy. This isn't good enough in 119 * general, since the _exit() is no return, so 120 * the compiler is free to corrupt all the local 121 * variables. 122 */ 123 (void)_close(pdes[0]); 124 if (pdes[1] != STDOUT_FILENO) { 125 (void)_dup2(pdes[1], STDOUT_FILENO); 126 (void)_close(pdes[1]); 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 } else { 132 if (pdes[0] != STDIN_FILENO) { 133 (void)_dup2(pdes[0], STDIN_FILENO); 134 (void)_close(pdes[0]); 135 } 136 (void)_close(pdes[1]); 137 } 138 SLIST_FOREACH(p, &pidlist, next) 139 (void)_close(fileno(p->fp)); 140 _execve(_PATH_BSHELL, argv, environ); 141 _exit(127); 142 /* NOTREACHED */ 143 } 144 THREAD_UNLOCK(); 145 146 /* Parent; assume fdopen can't fail. */ 147 if (*type == 'r') { 148 iop = fdopen(pdes[0], type); 149 (void)_close(pdes[1]); 150 } else { 151 iop = fdopen(pdes[1], type); 152 (void)_close(pdes[0]); 153 } 154 155 /* Link into list of file descriptors. */ 156 cur->fp = iop; 157 cur->pid = pid; 158 THREAD_LOCK(); 159 SLIST_INSERT_HEAD(&pidlist, cur, next); 160 THREAD_UNLOCK(); 161 162 return (iop); 163 } 164 165 /* 166 * pclose -- 167 * Pclose returns -1 if stream is not associated with a `popened' command, 168 * if already `pclosed', or waitpid returns an error. 169 */ 170 int 171 pclose(iop) 172 FILE *iop; 173 { 174 struct pid *cur, *last = NULL; 175 int pstat; 176 pid_t pid; 177 178 /* 179 * Find the appropriate file pointer and remove it from the list. 180 */ 181 THREAD_LOCK(); 182 SLIST_FOREACH(cur, &pidlist, next) { 183 if (cur->fp == iop) 184 break; 185 last = cur; 186 } 187 if (cur == NULL) { 188 THREAD_UNLOCK(); 189 return (-1); 190 } 191 if (last == NULL) 192 SLIST_REMOVE_HEAD(&pidlist, next); 193 else 194 SLIST_REMOVE_AFTER(last, next); 195 THREAD_UNLOCK(); 196 197 (void)fclose(iop); 198 199 do { 200 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 201 } while (pid == -1 && errno == EINTR); 202 203 free(cur); 204 205 return (pid == -1 ? -1 : pstat); 206 } 207