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 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95"; 41 #endif /* LIBC_SCCS and not lint */ 42 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 54 extern char **environ; 55 56 static struct pid { 57 struct pid *next; 58 FILE *fp; 59 pid_t pid; 60 } *pidlist; 61 62 FILE * 63 popen(command, type) 64 const char *command, *type; 65 { 66 struct pid *cur; 67 FILE *iop; 68 int pdes[2], pid, twoway; 69 char *argv[4]; 70 struct pid *p; 71 72 /* 73 * Lite2 introduced two-way popen() pipes using socketpair(). 74 * FreeBSD's pipe() is bidirectional, so we use that. 75 */ 76 if (strchr(type, '+')) { 77 twoway = 1; 78 type = "r+"; 79 } else { 80 twoway = 0; 81 if ((*type != 'r' && *type != 'w') || type[1]) 82 return (NULL); 83 } 84 if (pipe(pdes) < 0) 85 return (NULL); 86 87 if ((cur = malloc(sizeof(struct pid))) == NULL) { 88 (void)_close(pdes[0]); 89 (void)_close(pdes[1]); 90 return (NULL); 91 } 92 93 argv[0] = "sh"; 94 argv[1] = "-c"; 95 argv[2] = (char *)command; 96 argv[3] = NULL; 97 98 switch (pid = vfork()) { 99 case -1: /* Error. */ 100 (void)_close(pdes[0]); 101 (void)_close(pdes[1]); 102 free(cur); 103 return (NULL); 104 /* NOTREACHED */ 105 case 0: /* Child. */ 106 if (*type == 'r') { 107 /* 108 * The dup2() to STDIN_FILENO is repeated to avoid 109 * writing to pdes[1], which might corrupt the 110 * parent's copy. This isn't good enough in 111 * general, since the _exit() is no return, so 112 * the compiler is free to corrupt all the local 113 * variables. 114 */ 115 (void)_close(pdes[0]); 116 if (pdes[1] != STDOUT_FILENO) { 117 (void)dup2(pdes[1], STDOUT_FILENO); 118 (void)_close(pdes[1]); 119 if (twoway) 120 (void)dup2(STDOUT_FILENO, STDIN_FILENO); 121 } else if (twoway && (pdes[1] != STDIN_FILENO)) 122 (void)dup2(pdes[1], STDIN_FILENO); 123 } else { 124 if (pdes[0] != STDIN_FILENO) { 125 (void)dup2(pdes[0], STDIN_FILENO); 126 (void)_close(pdes[0]); 127 } 128 (void)_close(pdes[1]); 129 } 130 for (p = pidlist; p; p = p->next) { 131 (void)_close(fileno(p->fp)); 132 } 133 execve(_PATH_BSHELL, argv, environ); 134 _exit(127); 135 /* NOTREACHED */ 136 } 137 138 /* Parent; assume fdopen can't fail. */ 139 if (*type == 'r') { 140 iop = fdopen(pdes[0], type); 141 (void)_close(pdes[1]); 142 } else { 143 iop = fdopen(pdes[1], type); 144 (void)_close(pdes[0]); 145 } 146 147 /* Link into list of file descriptors. */ 148 cur->fp = iop; 149 cur->pid = pid; 150 cur->next = pidlist; 151 pidlist = cur; 152 153 return (iop); 154 } 155 156 /* 157 * pclose -- 158 * Pclose returns -1 if stream is not associated with a `popened' command, 159 * if already `pclosed', or waitpid returns an error. 160 */ 161 int 162 pclose(iop) 163 FILE *iop; 164 { 165 register struct pid *cur, *last; 166 int omask; 167 int pstat; 168 pid_t pid; 169 170 /* Find the appropriate file pointer. */ 171 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 172 if (cur->fp == iop) 173 break; 174 if (cur == NULL) 175 return (-1); 176 177 (void)fclose(iop); 178 179 do { 180 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 181 } while (pid == -1 && errno == EINTR); 182 183 /* Remove the entry from the linked list. */ 184 if (last == NULL) 185 pidlist = cur->next; 186 else 187 last->next = cur->next; 188 free(cur); 189 190 return (pid == -1 ? -1 : pstat); 191 } 192