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 37 #if defined(LIBC_SCCS) && !defined(lint) 38 /* static char sccsid[] = "@(#)popen.c 8.1 (Berkeley) 6/4/93"; */ 39 static char *rcsid = "$Id: popen.c,v 1.9 1994/05/09 16:28:27 jtc Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 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 static struct pid { 54 struct pid *next; 55 FILE *fp; 56 pid_t pid; 57 } *pidlist; 58 59 FILE * 60 popen(program, type) 61 const char *program; 62 const char *type; 63 { 64 struct pid *cur; 65 FILE *iop; 66 int pdes[2], pid; 67 68 if (*type != 'r' && *type != 'w' || type[1]) { 69 errno = EINVAL; 70 return (NULL); 71 } 72 73 if ((cur = malloc(sizeof(struct pid))) == NULL) 74 return (NULL); 75 76 if (pipe(pdes) < 0) { 77 (void)free(cur); 78 return (NULL); 79 } 80 81 switch (pid = vfork()) { 82 case -1: /* Error. */ 83 (void)close(pdes[0]); 84 (void)close(pdes[1]); 85 (void)free(cur); 86 return (NULL); 87 /* NOTREACHED */ 88 case 0: /* Child. */ 89 if (*type == 'r') { 90 if (pdes[1] != STDOUT_FILENO) { 91 (void)dup2(pdes[1], STDOUT_FILENO); 92 (void)close(pdes[1]); 93 } 94 (void) close(pdes[0]); 95 } else { 96 if (pdes[0] != STDIN_FILENO) { 97 (void)dup2(pdes[0], STDIN_FILENO); 98 (void)close(pdes[0]); 99 } 100 (void)close(pdes[1]); 101 } 102 execl(_PATH_BSHELL, "sh", "-c", program, (char *) 0); 103 _exit(127); 104 /* NOTREACHED */ 105 } 106 107 /* Parent; assume fdopen can't fail. */ 108 if (*type == 'r') { 109 iop = fdopen(pdes[0], type); 110 (void)close(pdes[1]); 111 } else { 112 iop = fdopen(pdes[1], type); 113 (void)close(pdes[0]); 114 } 115 116 /* Link into list of file descriptors. */ 117 cur->fp = iop; 118 cur->pid = pid; 119 cur->next = pidlist; 120 pidlist = cur; 121 122 return (iop); 123 } 124 125 /* 126 * pclose -- 127 * Pclose returns -1 if stream is not associated with a `popened' command, 128 * if already `pclosed', or waitpid returns an error. 129 */ 130 int 131 pclose(iop) 132 FILE *iop; 133 { 134 register struct pid *cur, *last; 135 int pstat; 136 pid_t pid; 137 138 (void)fclose(iop); 139 140 /* Find the appropriate file pointer. */ 141 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 142 if (cur->fp == iop) 143 break; 144 if (cur == NULL) 145 return (-1); 146 147 do { 148 pid = waitpid(cur->pid, &pstat, 0); 149 } while (pid == -1 && errno == EINTR); 150 151 /* Remove the entry from the linked list. */ 152 if (last == NULL) 153 pidlist = cur->next; 154 else 155 last->next = cur->next; 156 free(cur); 157 158 return (pid == -1 ? -1 : pstat); 159 } 160