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 8.3 (Berkeley) 5/3/95"; 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(command, type) 60 const char *command, *type; 61 { 62 struct pid *cur; 63 FILE *iop; 64 int pdes[2], pid, twoway; 65 66 /* 67 * Lite2 introduced two-way popen() pipes using socketpair(). 68 * FreeBSD's pipe() is bidirectional, so we use that. 69 */ 70 if (strchr(type, '+')) { 71 twoway = 1; 72 type = "r+"; 73 } else { 74 twoway = 0; 75 if ((*type != 'r' && *type != 'w') || type[1]) 76 return (NULL); 77 } 78 if (pipe(pdes) < 0) 79 return (NULL); 80 81 if ((cur = malloc(sizeof(struct pid))) == NULL) { 82 (void)close(pdes[0]); 83 (void)close(pdes[1]); 84 return (NULL); 85 } 86 87 switch (pid = vfork()) { 88 case -1: /* Error. */ 89 (void)close(pdes[0]); 90 (void)close(pdes[1]); 91 free(cur); 92 return (NULL); 93 /* NOTREACHED */ 94 case 0: /* Child. */ 95 if (*type == 'r') { 96 if (pdes[1] != STDOUT_FILENO) { 97 (void)dup2(pdes[1], STDOUT_FILENO); 98 (void)close(pdes[1]); 99 pdes[1] = STDOUT_FILENO; 100 } 101 (void) close(pdes[0]); 102 if (twoway && (pdes[1] != STDIN_FILENO)) 103 (void)dup2(pdes[1], STDIN_FILENO); 104 } else { 105 if (pdes[0] != STDIN_FILENO) { 106 (void)dup2(pdes[0], STDIN_FILENO); 107 (void)close(pdes[0]); 108 } 109 (void)close(pdes[1]); 110 } 111 execl(_PATH_BSHELL, "sh", "-c", command, NULL); 112 _exit(127); 113 /* NOTREACHED */ 114 } 115 116 /* Parent; assume fdopen can't fail. */ 117 if (*type == 'r') { 118 iop = fdopen(pdes[0], type); 119 (void)close(pdes[1]); 120 } else { 121 iop = fdopen(pdes[1], type); 122 (void)close(pdes[0]); 123 } 124 125 /* Link into list of file descriptors. */ 126 cur->fp = iop; 127 cur->pid = pid; 128 cur->next = pidlist; 129 pidlist = cur; 130 131 return (iop); 132 } 133 134 /* 135 * pclose -- 136 * Pclose returns -1 if stream is not associated with a `popened' command, 137 * if already `pclosed', or waitpid returns an error. 138 */ 139 int 140 pclose(iop) 141 FILE *iop; 142 { 143 register struct pid *cur, *last; 144 int omask; 145 int pstat; 146 pid_t pid; 147 148 /* Find the appropriate file pointer. */ 149 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 150 if (cur->fp == iop) 151 break; 152 if (cur == NULL) 153 return (-1); 154 155 (void)fclose(iop); 156 157 do { 158 pid = waitpid(cur->pid, &pstat, 0); 159 } while (pid == -1 && errno == EINTR); 160 161 /* Remove the entry from the linked list. */ 162 if (last == NULL) 163 pidlist = cur->next; 164 else 165 last->next = cur->next; 166 free(cur); 167 168 return (pid == -1 ? -1 : pstat); 169 } 170