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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD: src/lib/libc/gen/popen.c,v 1.14 2000/01/27 23:06:19 jasone Exp $ 37 * $DragonFly: src/lib/libc/gen/popen.c,v 1.4 2005/01/31 22:29:15 dillon Exp $ 38 * 39 * @(#)popen.c 8.3 (Berkeley) 5/3/95 40 */ 41 42 #include "namespace.h" 43 #include <sys/param.h> 44 #include <sys/wait.h> 45 46 #include <signal.h> 47 #include <errno.h> 48 #include <unistd.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <paths.h> 53 #include "un-namespace.h" 54 55 extern char **environ; 56 57 static struct pid { 58 struct pid *next; 59 FILE *fp; 60 pid_t pid; 61 } *pidlist; 62 63 FILE * 64 popen(command, type) 65 const char *command, *type; 66 { 67 struct pid *cur; 68 FILE *iop; 69 int pdes[2], pid, twoway; 70 char *argv[4]; 71 struct pid *p; 72 73 /* 74 * Lite2 introduced two-way popen() pipes using _socketpair(). 75 * FreeBSD's pipe() is bidirectional, so we use that. 76 */ 77 if (strchr(type, '+')) { 78 twoway = 1; 79 type = "r+"; 80 } else { 81 twoway = 0; 82 if ((*type != 'r' && *type != 'w') || type[1]) 83 return (NULL); 84 } 85 if (pipe(pdes) < 0) 86 return (NULL); 87 88 if ((cur = malloc(sizeof(struct pid))) == NULL) { 89 (void)_close(pdes[0]); 90 (void)_close(pdes[1]); 91 return (NULL); 92 } 93 94 argv[0] = "sh"; 95 argv[1] = "-c"; 96 argv[2] = (char *)command; 97 argv[3] = NULL; 98 99 switch (pid = vfork()) { 100 case -1: /* Error. */ 101 (void)_close(pdes[0]); 102 (void)_close(pdes[1]); 103 free(cur); 104 return (NULL); 105 /* NOTREACHED */ 106 case 0: /* Child. */ 107 if (*type == 'r') { 108 /* 109 * The _dup2() to STDIN_FILENO is repeated to avoid 110 * writing to pdes[1], which might corrupt the 111 * parent's copy. This isn't good enough in 112 * general, since the _exit() is no return, so 113 * the compiler is free to corrupt all the local 114 * variables. 115 */ 116 (void)_close(pdes[0]); 117 if (pdes[1] != STDOUT_FILENO) { 118 (void)_dup2(pdes[1], STDOUT_FILENO); 119 (void)_close(pdes[1]); 120 if (twoway) 121 (void)_dup2(STDOUT_FILENO, STDIN_FILENO); 122 } else if (twoway && (pdes[1] != STDIN_FILENO)) 123 (void)_dup2(pdes[1], STDIN_FILENO); 124 } else { 125 if (pdes[0] != STDIN_FILENO) { 126 (void)_dup2(pdes[0], STDIN_FILENO); 127 (void)_close(pdes[0]); 128 } 129 (void)_close(pdes[1]); 130 } 131 for (p = pidlist; p; p = p->next) { 132 (void)_close(fileno(p->fp)); 133 } 134 _execve(_PATH_BSHELL, argv, environ); 135 _exit(127); 136 /* NOTREACHED */ 137 } 138 139 /* Parent; assume fdopen can't fail. */ 140 if (*type == 'r') { 141 iop = fdopen(pdes[0], type); 142 (void)_close(pdes[1]); 143 } else { 144 iop = fdopen(pdes[1], type); 145 (void)_close(pdes[0]); 146 } 147 148 /* Link into list of file descriptors. */ 149 cur->fp = iop; 150 cur->pid = pid; 151 cur->next = pidlist; 152 pidlist = cur; 153 154 return (iop); 155 } 156 157 /* 158 * pclose -- 159 * Pclose returns -1 if stream is not associated with a `popened' command, 160 * if already `pclosed', or waitpid returns an error. 161 */ 162 int 163 pclose(iop) 164 FILE *iop; 165 { 166 struct pid *cur, *last; 167 int omask; 168 int pstat; 169 pid_t pid; 170 171 /* Find the appropriate file pointer. */ 172 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 173 if (cur->fp == iop) 174 break; 175 if (cur == NULL) 176 return (-1); 177 178 (void)fclose(iop); 179 180 do { 181 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 182 } while (pid == -1 && errno == EINTR); 183 184 /* Remove the entry from the linked list. */ 185 if (last == NULL) 186 pidlist = cur->next; 187 else 188 last->next = cur->next; 189 free(cur); 190 191 return (pid == -1 ? -1 : pstat); 192 } 193