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 1.10 2001/07/09 07:04:39 deraadt 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 #ifdef __GNUC__ 68 (void)&cur; 69 #endif 70 71 if ((*type != 'r' && *type != 'w') || type[1] != '\0') { 72 errno = EINVAL; 73 return (NULL); 74 } 75 76 if ((cur = malloc(sizeof(struct pid))) == NULL) 77 return (NULL); 78 79 if (pipe(pdes) < 0) { 80 free(cur); 81 return (NULL); 82 } 83 84 switch (pid = vfork()) { 85 case -1: /* Error. */ 86 (void)close(pdes[0]); 87 (void)close(pdes[1]); 88 free(cur); 89 return (NULL); 90 /* NOTREACHED */ 91 case 0: /* Child. */ 92 { 93 struct pid *pcur; 94 /* 95 * because vfork() instead of fork(), must leak FILE *, 96 * but luckily we are terminally headed for an execl() 97 */ 98 for (pcur = pidlist; pcur; pcur = pcur->next) 99 close(fileno(pcur->fp)); 100 101 if (*type == 'r') { 102 int tpdes1 = pdes[1]; 103 104 (void) close(pdes[0]); 105 /* 106 * We must NOT modify pdes, due to the 107 * semantics of vfork. 108 */ 109 if (tpdes1 != STDOUT_FILENO) { 110 (void)dup2(tpdes1, STDOUT_FILENO); 111 (void)close(tpdes1); 112 tpdes1 = STDOUT_FILENO; 113 } 114 } else { 115 (void)close(pdes[1]); 116 if (pdes[0] != STDIN_FILENO) { 117 (void)dup2(pdes[0], STDIN_FILENO); 118 (void)close(pdes[0]); 119 } 120 } 121 execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL); 122 _exit(127); 123 /* NOTREACHED */ 124 } 125 } 126 127 /* Parent; assume fdopen can't fail. */ 128 if (*type == 'r') { 129 iop = fdopen(pdes[0], type); 130 (void)close(pdes[1]); 131 } else { 132 iop = fdopen(pdes[1], type); 133 (void)close(pdes[0]); 134 } 135 136 /* Link into list of file descriptors. */ 137 cur->fp = iop; 138 cur->pid = pid; 139 cur->next = pidlist; 140 pidlist = cur; 141 142 return (iop); 143 } 144 145 /* 146 * pclose -- 147 * Pclose returns -1 if stream is not associated with a `popened' command, 148 * if already `pclosed', or waitpid returns an error. 149 */ 150 int 151 pclose(iop) 152 FILE *iop; 153 { 154 register struct pid *cur, *last; 155 int pstat; 156 pid_t pid; 157 158 (void)fclose(iop); 159 160 /* Find the appropriate file pointer. */ 161 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 162 if (cur->fp == iop) 163 break; 164 if (cur == NULL) 165 return (-1); 166 167 do { 168 pid = waitpid(cur->pid, &pstat, 0); 169 } while (pid == -1 && errno == EINTR); 170 171 /* Remove the entry from the linked list. */ 172 if (last == NULL) 173 pidlist = cur->next; 174 else 175 last->next = cur->next; 176 free(cur); 177 178 return (pid == -1 ? -1 : pstat); 179 } 180