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 1.2 2003/06/17 04:26:42 dillon Exp $ 38 * 39 * @(#)popen.c 8.3 (Berkeley) 5/3/95 40 */ 41 42 #include <sys/param.h> 43 #include <sys/wait.h> 44 45 #include <signal.h> 46 #include <errno.h> 47 #include <unistd.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <paths.h> 52 53 extern char **environ; 54 55 static struct pid { 56 struct pid *next; 57 FILE *fp; 58 pid_t pid; 59 } *pidlist; 60 61 FILE * 62 popen(command, type) 63 const char *command, *type; 64 { 65 struct pid *cur; 66 FILE *iop; 67 int pdes[2], pid, twoway; 68 char *argv[4]; 69 struct pid *p; 70 71 /* 72 * Lite2 introduced two-way popen() pipes using socketpair(). 73 * FreeBSD's pipe() is bidirectional, so we use that. 74 */ 75 if (strchr(type, '+')) { 76 twoway = 1; 77 type = "r+"; 78 } else { 79 twoway = 0; 80 if ((*type != 'r' && *type != 'w') || type[1]) 81 return (NULL); 82 } 83 if (pipe(pdes) < 0) 84 return (NULL); 85 86 if ((cur = malloc(sizeof(struct pid))) == NULL) { 87 (void)_close(pdes[0]); 88 (void)_close(pdes[1]); 89 return (NULL); 90 } 91 92 argv[0] = "sh"; 93 argv[1] = "-c"; 94 argv[2] = (char *)command; 95 argv[3] = NULL; 96 97 switch (pid = vfork()) { 98 case -1: /* Error. */ 99 (void)_close(pdes[0]); 100 (void)_close(pdes[1]); 101 free(cur); 102 return (NULL); 103 /* NOTREACHED */ 104 case 0: /* Child. */ 105 if (*type == 'r') { 106 /* 107 * The dup2() to STDIN_FILENO is repeated to avoid 108 * writing to pdes[1], which might corrupt the 109 * parent's copy. This isn't good enough in 110 * general, since the _exit() is no return, so 111 * the compiler is free to corrupt all the local 112 * variables. 113 */ 114 (void)_close(pdes[0]); 115 if (pdes[1] != STDOUT_FILENO) { 116 (void)dup2(pdes[1], STDOUT_FILENO); 117 (void)_close(pdes[1]); 118 if (twoway) 119 (void)dup2(STDOUT_FILENO, STDIN_FILENO); 120 } else if (twoway && (pdes[1] != STDIN_FILENO)) 121 (void)dup2(pdes[1], STDIN_FILENO); 122 } else { 123 if (pdes[0] != STDIN_FILENO) { 124 (void)dup2(pdes[0], STDIN_FILENO); 125 (void)_close(pdes[0]); 126 } 127 (void)_close(pdes[1]); 128 } 129 for (p = pidlist; p; p = p->next) { 130 (void)_close(fileno(p->fp)); 131 } 132 execve(_PATH_BSHELL, argv, environ); 133 _exit(127); 134 /* NOTREACHED */ 135 } 136 137 /* Parent; assume fdopen can't fail. */ 138 if (*type == 'r') { 139 iop = fdopen(pdes[0], type); 140 (void)_close(pdes[1]); 141 } else { 142 iop = fdopen(pdes[1], type); 143 (void)_close(pdes[0]); 144 } 145 146 /* Link into list of file descriptors. */ 147 cur->fp = iop; 148 cur->pid = pid; 149 cur->next = pidlist; 150 pidlist = cur; 151 152 return (iop); 153 } 154 155 /* 156 * pclose -- 157 * Pclose returns -1 if stream is not associated with a `popened' command, 158 * if already `pclosed', or waitpid returns an error. 159 */ 160 int 161 pclose(iop) 162 FILE *iop; 163 { 164 register struct pid *cur, *last; 165 int omask; 166 int pstat; 167 pid_t pid; 168 169 /* Find the appropriate file pointer. */ 170 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 171 if (cur->fp == iop) 172 break; 173 if (cur == NULL) 174 return (-1); 175 176 (void)fclose(iop); 177 178 do { 179 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 180 } while (pid == -1 && errno == EINTR); 181 182 /* Remove the entry from the linked list. */ 183 if (last == NULL) 184 pidlist = cur->next; 185 else 186 last->next = cur->next; 187 free(cur); 188 189 return (pid == -1 ? -1 : pstat); 190 } 191