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 1.11 2002/01/02 20:18:31 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]; 66 pid_t pid; 67 68 #ifdef __GNUC__ 69 (void)&cur; 70 #endif 71 72 if ((*type != 'r' && *type != 'w') || type[1] != '\0') { 73 errno = EINVAL; 74 return (NULL); 75 } 76 77 if ((cur = malloc(sizeof(struct pid))) == NULL) 78 return (NULL); 79 80 if (pipe(pdes) < 0) { 81 free(cur); 82 return (NULL); 83 } 84 85 switch (pid = vfork()) { 86 case -1: /* Error. */ 87 (void)close(pdes[0]); 88 (void)close(pdes[1]); 89 free(cur); 90 return (NULL); 91 /* NOTREACHED */ 92 case 0: /* Child. */ 93 { 94 struct pid *pcur; 95 /* 96 * because vfork() instead of fork(), must leak FILE *, 97 * but luckily we are terminally headed for an execl() 98 */ 99 for (pcur = pidlist; pcur; pcur = pcur->next) 100 close(fileno(pcur->fp)); 101 102 if (*type == 'r') { 103 int tpdes1 = pdes[1]; 104 105 (void) close(pdes[0]); 106 /* 107 * We must NOT modify pdes, due to the 108 * semantics of vfork. 109 */ 110 if (tpdes1 != STDOUT_FILENO) { 111 (void)dup2(tpdes1, STDOUT_FILENO); 112 (void)close(tpdes1); 113 tpdes1 = STDOUT_FILENO; 114 } 115 } else { 116 (void)close(pdes[1]); 117 if (pdes[0] != STDIN_FILENO) { 118 (void)dup2(pdes[0], STDIN_FILENO); 119 (void)close(pdes[0]); 120 } 121 } 122 execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL); 123 _exit(127); 124 /* NOTREACHED */ 125 } 126 } 127 128 /* Parent; assume fdopen can't fail. */ 129 if (*type == 'r') { 130 iop = fdopen(pdes[0], type); 131 (void)close(pdes[1]); 132 } else { 133 iop = fdopen(pdes[1], type); 134 (void)close(pdes[0]); 135 } 136 137 /* Link into list of file descriptors. */ 138 cur->fp = iop; 139 cur->pid = pid; 140 cur->next = pidlist; 141 pidlist = cur; 142 143 return (iop); 144 } 145 146 /* 147 * pclose -- 148 * Pclose returns -1 if stream is not associated with a `popened' command, 149 * if already `pclosed', or waitpid returns an error. 150 */ 151 int 152 pclose(iop) 153 FILE *iop; 154 { 155 register struct pid *cur, *last; 156 int pstat; 157 pid_t pid; 158 159 (void)fclose(iop); 160 161 /* Find the appropriate file pointer. */ 162 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 163 if (cur->fp == iop) 164 break; 165 if (cur == NULL) 166 return (-1); 167 168 do { 169 pid = waitpid(cur->pid, &pstat, 0); 170 } while (pid == -1 && errno == EINTR); 171 172 /* Remove the entry from the linked list. */ 173 if (last == NULL) 174 pidlist = cur->next; 175 else 176 last->next = cur->next; 177 free(cur); 178 179 return (pid == -1 ? -1 : pstat); 180 } 181