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 * 3. 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 * @(#)popen.c 8.3 (Berkeley) 5/3/95 33 * $FreeBSD: src/lib/libc/gen/popen.c,v 1.20 2008/07/29 16:29:59 ed Exp $ 34 * $DragonFly: src/lib/libc/gen/popen.3,v 1.4 2006/04/08 08:17:06 swildner Exp $ 35 */ 36 37 #include "namespace.h" 38 #include <sys/param.h> 39 #include <sys/queue.h> 40 #include <sys/wait.h> 41 42 #include <signal.h> 43 #include <errno.h> 44 #include <unistd.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <paths.h> 49 #include <pthread.h> 50 #include "un-namespace.h" 51 #include "libc_private.h" 52 53 extern char **environ; 54 55 struct pid { 56 SLIST_ENTRY(pid) next; 57 FILE *fp; 58 pid_t pid; 59 }; 60 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(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(const char *command, const char *type) 68 { 69 struct pid *cur; 70 FILE *iop; 71 int pdes[2], pid, twoway; 72 const char *argv[4]; 73 struct pid *p; 74 75 /* 76 * Lite2 introduced two-way popen() pipes using _socketpair(). 77 * FreeBSD's pipe() is bidirectional, so we use that. 78 */ 79 if (strchr(type, '+')) { 80 twoway = 1; 81 type = "r+"; 82 } else { 83 twoway = 0; 84 if ((*type != 'r' && *type != 'w') || type[1]) 85 return (NULL); 86 } 87 if (pipe(pdes) < 0) 88 return (NULL); 89 90 if ((cur = malloc(sizeof(struct pid))) == NULL) { 91 _close(pdes[0]); 92 _close(pdes[1]); 93 return (NULL); 94 } 95 96 argv[0] = "sh"; 97 argv[1] = "-c"; 98 argv[2] = command; 99 argv[3] = NULL; 100 101 THREAD_LOCK(); 102 switch (pid = vfork()) { 103 case -1: /* Error. */ 104 THREAD_UNLOCK(); 105 _close(pdes[0]); 106 _close(pdes[1]); 107 free(cur); 108 return (NULL); 109 /* NOTREACHED */ 110 case 0: /* Child. */ 111 if (*type == 'r') { 112 /* 113 * The _dup2() to STDIN_FILENO is repeated to avoid 114 * writing to pdes[1], which might corrupt the 115 * parent's copy. This isn't good enough in 116 * general, since the _exit() is no return, so 117 * the compiler is free to corrupt all the local 118 * variables. 119 */ 120 _close(pdes[0]); 121 if (pdes[1] != STDOUT_FILENO) { 122 _dup2(pdes[1], STDOUT_FILENO); 123 _close(pdes[1]); 124 if (twoway) 125 _dup2(STDOUT_FILENO, STDIN_FILENO); 126 } else if (twoway && (pdes[1] != STDIN_FILENO)) 127 _dup2(pdes[1], STDIN_FILENO); 128 } else { 129 if (pdes[0] != STDIN_FILENO) { 130 _dup2(pdes[0], STDIN_FILENO); 131 _close(pdes[0]); 132 } 133 _close(pdes[1]); 134 } 135 SLIST_FOREACH(p, &pidlist, next) 136 _close(fileno(p->fp)); 137 _execve(_PATH_BSHELL, __DECONST(char * const *, argv), environ); 138 _exit(127); 139 /* NOTREACHED */ 140 } 141 THREAD_UNLOCK(); 142 143 /* Parent; assume fdopen can't fail. */ 144 if (*type == 'r') { 145 iop = fdopen(pdes[0], type); 146 _close(pdes[1]); 147 } else { 148 iop = fdopen(pdes[1], type); 149 _close(pdes[0]); 150 } 151 152 /* Link into list of file descriptors. */ 153 cur->fp = iop; 154 cur->pid = pid; 155 THREAD_LOCK(); 156 SLIST_INSERT_HEAD(&pidlist, cur, next); 157 THREAD_UNLOCK(); 158 159 return (iop); 160 } 161 162 /* 163 * pclose -- 164 * Pclose returns -1 if stream is not associated with a `popened' command, 165 * if already `pclosed', or waitpid returns an error. 166 */ 167 int 168 pclose(FILE *iop) 169 { 170 struct pid *cur, *last = NULL; 171 int pstat; 172 pid_t pid; 173 174 /* 175 * Find the appropriate file pointer and remove it from the list. 176 */ 177 THREAD_LOCK(); 178 SLIST_FOREACH(cur, &pidlist, next) { 179 if (cur->fp == iop) 180 break; 181 last = cur; 182 } 183 if (cur == NULL) { 184 THREAD_UNLOCK(); 185 return (-1); 186 } 187 if (last == NULL) 188 SLIST_REMOVE_HEAD(&pidlist, next); 189 else 190 SLIST_REMOVE_AFTER(last, next); 191 THREAD_UNLOCK(); 192 193 fclose(iop); 194 195 do { 196 pid = _wait4(cur->pid, &pstat, 0, NULL); 197 } while (pid == -1 && errno == EINTR); 198 199 free(cur); 200 201 return (pid == -1 ? -1 : pstat); 202 } 203