1 /* $NetBSD: popen.c,v 1.22 1998/07/18 05:04:35 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software written by Ken Arnold and 8 * published in UNIX Review, Vol. 6, No. 8. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95"; 43 #else 44 __RCSID("$NetBSD: popen.c,v 1.22 1998/07/18 05:04:35 lukem Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include "namespace.h" 49 #include <sys/param.h> 50 #include <sys/wait.h> 51 #include <sys/socket.h> 52 53 #include <signal.h> 54 #include <errno.h> 55 #include <unistd.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <paths.h> 60 61 #ifdef __weak_alias 62 __weak_alias(popen,_popen); 63 __weak_alias(pclose,_pclose); 64 #endif 65 66 static struct pid { 67 struct pid *next; 68 FILE *fp; 69 pid_t pid; 70 } *pidlist; 71 72 FILE * 73 popen(command, type) 74 const char *command, *type; 75 { 76 struct pid *cur, *old; 77 FILE *iop; 78 int pdes[2], pid, twoway; 79 80 #ifdef __GNUC__ 81 /* This outrageous construct just to shut up a GCC warning. */ 82 (void) &cur; (void) &twoway; (void) &type; 83 #endif 84 85 if (strchr(type, '+')) { 86 twoway = 1; 87 type = "r+"; 88 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, pdes) < 0) 89 return (NULL); 90 } else { 91 twoway = 0; 92 if ((*type != 'r' && *type != 'w') || type[1] || 93 (pipe(pdes) < 0)) { 94 errno = EINVAL; 95 return (NULL); 96 } 97 } 98 99 if ((cur = malloc(sizeof(struct pid))) == NULL) { 100 (void)close(pdes[0]); 101 (void)close(pdes[1]); 102 return (NULL); 103 } 104 105 switch (pid = vfork()) { 106 case -1: /* Error. */ 107 free(cur); 108 (void)close(pdes[0]); 109 (void)close(pdes[1]); 110 return (NULL); 111 /* NOTREACHED */ 112 case 0: /* Child. */ 113 /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams 114 from previous popen() calls that remain open in the 115 parent process are closed in the new child process. */ 116 for (old = pidlist; old; old = old->next) 117 close(fileno(old->fp)); /* don't allow a flush */ 118 119 if (*type == 'r') { 120 (void)close(pdes[0]); 121 if (pdes[1] != STDOUT_FILENO) { 122 (void)dup2(pdes[1], STDOUT_FILENO); 123 (void)close(pdes[1]); 124 } 125 if (twoway) 126 (void)dup2(STDOUT_FILENO, STDIN_FILENO); 127 } else { 128 (void)close(pdes[1]); 129 if (pdes[0] != STDIN_FILENO) { 130 (void)dup2(pdes[0], STDIN_FILENO); 131 (void)close(pdes[0]); 132 } 133 } 134 135 execl(_PATH_BSHELL, "sh", "-c", command, NULL); 136 _exit(127); 137 /* NOTREACHED */ 138 } 139 140 /* Parent; assume fdopen can't fail. */ 141 if (*type == 'r') { 142 iop = fdopen(pdes[0], type); 143 (void)close(pdes[1]); 144 } else { 145 iop = fdopen(pdes[1], type); 146 (void)close(pdes[0]); 147 } 148 149 /* Link into list of file descriptors. */ 150 cur->fp = iop; 151 cur->pid = pid; 152 cur->next = pidlist; 153 pidlist = cur; 154 155 return (iop); 156 } 157 158 /* 159 * pclose -- 160 * Pclose returns -1 if stream is not associated with a `popened' command, 161 * if already `pclosed', or waitpid returns an error. 162 */ 163 int 164 pclose(iop) 165 FILE *iop; 166 { 167 struct pid *cur, *last; 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 = waitpid(cur->pid, &pstat, 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