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/wait.h> 42 43 #include <signal.h> 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <paths.h> 50 #include <pthread.h> 51 #include "un-namespace.h" 52 #include "libc_private.h" 53 54 extern char **environ; 55 56 static struct pid { 57 struct pid *next; 58 FILE *fp; 59 pid_t pid; 60 } *pidlist; 61 static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER; 62 63 #define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex) 64 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex) 65 66 FILE * 67 popen(command, type) 68 const char *command, *type; 69 { 70 struct pid *cur; 71 FILE *iop; 72 int pdes[2], pid, twoway; 73 char *argv[4]; 74 struct pid *p; 75 76 /* 77 * Lite2 introduced two-way popen() pipes using _socketpair(). 78 * FreeBSD's pipe() is bidirectional, so we use that. 79 */ 80 if (strchr(type, '+')) { 81 twoway = 1; 82 type = "r+"; 83 } else { 84 twoway = 0; 85 if ((*type != 'r' && *type != 'w') || type[1]) 86 return (NULL); 87 } 88 if (pipe(pdes) < 0) 89 return (NULL); 90 91 if ((cur = malloc(sizeof(struct pid))) == NULL) { 92 (void)_close(pdes[0]); 93 (void)_close(pdes[1]); 94 return (NULL); 95 } 96 97 argv[0] = "sh"; 98 argv[1] = "-c"; 99 argv[2] = (char *)command; 100 argv[3] = NULL; 101 102 THREAD_LOCK(); 103 switch (pid = vfork()) { 104 case -1: /* Error. */ 105 THREAD_UNLOCK(); 106 (void)_close(pdes[0]); 107 (void)_close(pdes[1]); 108 free(cur); 109 return (NULL); 110 /* NOTREACHED */ 111 case 0: /* Child. */ 112 if (*type == 'r') { 113 /* 114 * The _dup2() to STDIN_FILENO is repeated to avoid 115 * writing to pdes[1], which might corrupt the 116 * parent's copy. This isn't good enough in 117 * general, since the _exit() is no return, so 118 * the compiler is free to corrupt all the local 119 * variables. 120 */ 121 (void)_close(pdes[0]); 122 if (pdes[1] != STDOUT_FILENO) { 123 (void)_dup2(pdes[1], STDOUT_FILENO); 124 (void)_close(pdes[1]); 125 if (twoway) 126 (void)_dup2(STDOUT_FILENO, STDIN_FILENO); 127 } else if (twoway && (pdes[1] != STDIN_FILENO)) 128 (void)_dup2(pdes[1], STDIN_FILENO); 129 } else { 130 if (pdes[0] != STDIN_FILENO) { 131 (void)_dup2(pdes[0], STDIN_FILENO); 132 (void)_close(pdes[0]); 133 } 134 (void)_close(pdes[1]); 135 } 136 for (p = pidlist; p; p = p->next) { 137 (void)_close(fileno(p->fp)); 138 } 139 _execve(_PATH_BSHELL, argv, environ); 140 _exit(127); 141 /* NOTREACHED */ 142 } 143 THREAD_UNLOCK(); 144 145 /* Parent; assume fdopen can't fail. */ 146 if (*type == 'r') { 147 iop = fdopen(pdes[0], type); 148 (void)_close(pdes[1]); 149 } else { 150 iop = fdopen(pdes[1], type); 151 (void)_close(pdes[0]); 152 } 153 154 /* Link into list of file descriptors. */ 155 cur->fp = iop; 156 cur->pid = pid; 157 THREAD_LOCK(); 158 cur->next = pidlist; 159 pidlist = cur; 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; 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 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 183 if (cur->fp == iop) 184 break; 185 if (cur == NULL) { 186 THREAD_UNLOCK(); 187 return (-1); 188 } 189 if (last == NULL) 190 pidlist = cur->next; 191 else 192 last->next = cur->next; 193 THREAD_UNLOCK(); 194 195 (void)fclose(iop); 196 197 do { 198 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 199 } while (pid == -1 && errno == EINTR); 200 201 free(cur); 202 203 return (pid == -1 ? -1 : pstat); 204 } 205