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 rcsid[] = "$OpenBSD: popen.c,v 1.3 1996/08/19 08:25:20 tholo Exp $"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 #include <sys/wait.h> 43 44 #include <signal.h> 45 #include <errno.h> 46 #include <unistd.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <paths.h> 51 52 static struct pid { 53 struct pid *next; 54 FILE *fp; 55 pid_t pid; 56 } *pidlist; 57 58 FILE * 59 popen(program, type) 60 const char *program; 61 const char *type; 62 { 63 struct pid *cur; 64 FILE *iop; 65 int pdes[2], pid; 66 67 if (*type != 'r' && *type != 'w' || type[1]) { 68 errno = EINVAL; 69 return (NULL); 70 } 71 72 if ((cur = malloc(sizeof(struct pid))) == NULL) 73 return (NULL); 74 75 if (pipe(pdes) < 0) { 76 free(cur); 77 return (NULL); 78 } 79 80 switch (pid = vfork()) { 81 case -1: /* Error. */ 82 (void)close(pdes[0]); 83 (void)close(pdes[1]); 84 free(cur); 85 return (NULL); 86 /* NOTREACHED */ 87 case 0: /* Child. */ 88 if (*type == 'r') { 89 if (pdes[1] != STDOUT_FILENO) { 90 (void)dup2(pdes[1], STDOUT_FILENO); 91 (void)close(pdes[1]); 92 } 93 (void) close(pdes[0]); 94 } else { 95 if (pdes[0] != STDIN_FILENO) { 96 (void)dup2(pdes[0], STDIN_FILENO); 97 (void)close(pdes[0]); 98 } 99 (void)close(pdes[1]); 100 } 101 /* 102 * because vfork() instead of fork(), must leak FILE *, 103 * but luckily we are terminally headed for an execl() 104 */ 105 for (cur = pidlist; cur; cur = cur->next) 106 close(fileno(cur->fp)); 107 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 108 _exit(127); 109 /* NOTREACHED */ 110 } 111 112 /* Parent; assume fdopen can't fail. */ 113 if (*type == 'r') { 114 iop = fdopen(pdes[0], type); 115 (void)close(pdes[1]); 116 } else { 117 iop = fdopen(pdes[1], type); 118 (void)close(pdes[0]); 119 } 120 121 /* Link into list of file descriptors. */ 122 cur->fp = iop; 123 cur->pid = pid; 124 cur->next = pidlist; 125 pidlist = cur; 126 127 return (iop); 128 } 129 130 /* 131 * pclose -- 132 * Pclose returns -1 if stream is not associated with a `popened' command, 133 * if already `pclosed', or waitpid returns an error. 134 */ 135 int 136 pclose(iop) 137 FILE *iop; 138 { 139 register struct pid *cur, *last; 140 int pstat; 141 pid_t pid; 142 143 (void)fclose(iop); 144 145 /* Find the appropriate file pointer. */ 146 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 147 if (cur->fp == iop) 148 break; 149 if (cur == NULL) 150 return (-1); 151 152 do { 153 pid = waitpid(cur->pid, &pstat, 0); 154 } while (pid == -1 && errno == EINTR); 155 156 /* Remove the entry from the linked list. */ 157 if (last == NULL) 158 pidlist = cur->next; 159 else 160 last->next = cur->next; 161 free(cur); 162 163 return (pid == -1 ? -1 : pstat); 164 } 165