1 /* $OpenBSD: popen.c,v 1.22 2019/06/28 13:32:41 deraadt Exp $ */ 2 /* 3 * Copyright (c) 1988, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software written by Ken Arnold and 7 * published in UNIX Review, Vol. 6, No. 8. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/wait.h> 35 36 #include <signal.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <unistd.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <paths.h> 44 #include <wchar.h> 45 #include "thread_private.h" 46 47 static struct pid { 48 struct pid *next; 49 FILE *fp; 50 pid_t pid; 51 } *pidlist; 52 53 static void *pidlist_lock = NULL; 54 55 FILE * 56 popen(const char *program, const char *type) 57 { 58 struct pid * volatile cur; 59 FILE *iop; 60 int pdes[2]; 61 int target; 62 pid_t pid; 63 64 if ((*type != 'r' && *type != 'w') || 65 (type[1] != '\0' && (type[1] != 'e' || type[2] != '\0'))) { 66 errno = EINVAL; 67 return (NULL); 68 } 69 70 if ((cur = malloc(sizeof(struct pid))) == NULL) 71 return (NULL); 72 73 if (pipe2(pdes, O_CLOEXEC) == -1) { 74 free(cur); 75 return (NULL); 76 } 77 78 _MUTEX_LOCK(&pidlist_lock); 79 switch (pid = vfork()) { 80 case -1: /* Error. */ 81 _MUTEX_UNLOCK(&pidlist_lock); 82 (void)close(pdes[0]); 83 (void)close(pdes[1]); 84 free(cur); 85 return (NULL); 86 /* NOTREACHED */ 87 case 0: /* Child. */ 88 { 89 struct pid *pcur; 90 91 /* 92 * because vfork() instead of fork(), must leak FILE *, 93 * but luckily we are terminally headed for an execl() 94 */ 95 for (pcur = pidlist; pcur; pcur = pcur->next) 96 close(fileno(pcur->fp)); 97 98 target = *type == 'r'; 99 if (pdes[target] != target) { 100 if (dup2(pdes[target], target) == -1) 101 _exit(127); 102 } else { 103 int flags = fcntl(pdes[target], F_GETFD); 104 if (flags == -1 || ((flags & FD_CLOEXEC) && 105 fcntl(pdes[target], F_SETFD, flags & ~FD_CLOEXEC) 106 == -1)) 107 _exit(127); 108 } 109 110 execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL); 111 _exit(127); 112 /* NOTREACHED */ 113 } 114 } 115 _MUTEX_UNLOCK(&pidlist_lock); 116 117 /* Parent; assume fdopen can't fail. */ 118 target = *type == 'w'; 119 iop = fdopen(pdes[target], type); 120 fwide(iop, -1); 121 (void)close(pdes[!target]); 122 123 /* Link into list of file descriptors. */ 124 cur->fp = iop; 125 cur->pid = pid; 126 _MUTEX_LOCK(&pidlist_lock); 127 cur->next = pidlist; 128 pidlist = cur; 129 _MUTEX_UNLOCK(&pidlist_lock); 130 131 /* now that it's in the list, clear FD_CLOEXEC if unwanted */ 132 if (type[1] != 'e') { 133 int flags = fcntl(pdes[target], F_GETFD); 134 if (flags != -1) 135 fcntl(pdes[target], F_SETFD, flags & ~FD_CLOEXEC); 136 } 137 138 return (iop); 139 } 140 DEF_WEAK(popen); 141 142 /* 143 * pclose -- 144 * Pclose returns -1 if stream is not associated with a `popened' command, 145 * if already `pclosed', or waitpid returns an error. 146 */ 147 int 148 pclose(FILE *iop) 149 { 150 struct pid *cur, *last; 151 int pstat; 152 pid_t pid; 153 154 /* Find the appropriate file pointer. */ 155 _MUTEX_LOCK(&pidlist_lock); 156 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 157 if (cur->fp == iop) 158 break; 159 160 if (cur == NULL) { 161 _MUTEX_UNLOCK(&pidlist_lock); 162 return (-1); 163 } 164 165 /* Remove the entry from the linked list. */ 166 if (last == NULL) 167 pidlist = cur->next; 168 else 169 last->next = cur->next; 170 _MUTEX_UNLOCK(&pidlist_lock); 171 172 (void)fclose(iop); 173 174 do { 175 pid = waitpid(cur->pid, &pstat, 0); 176 } while (pid == -1 && errno == EINTR); 177 178 free(cur); 179 180 return (pid == -1 ? -1 : pstat); 181 } 182 DEF_WEAK(pclose); 183