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 1.12 2002/01/16 01:28:54 millert 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 * volatile cur; 64 FILE *iop; 65 int pdes[2]; 66 pid_t pid; 67 68 if ((*type != 'r' && *type != 'w') || type[1] != '\0') { 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 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 free(cur); 86 return (NULL); 87 /* NOTREACHED */ 88 case 0: /* Child. */ 89 { 90 struct pid *pcur; 91 /* 92 * because vfork() instead of fork(), must leak FILE *, 93 * but luckily we are terminally headed for an execl() 94 */ 95 for (pcur = pidlist; pcur; pcur = pcur->next) 96 close(fileno(pcur->fp)); 97 98 if (*type == 'r') { 99 int tpdes1 = pdes[1]; 100 101 (void) close(pdes[0]); 102 /* 103 * We must NOT modify pdes, due to the 104 * semantics of vfork. 105 */ 106 if (tpdes1 != STDOUT_FILENO) { 107 (void)dup2(tpdes1, STDOUT_FILENO); 108 (void)close(tpdes1); 109 tpdes1 = STDOUT_FILENO; 110 } 111 } else { 112 (void)close(pdes[1]); 113 if (pdes[0] != STDIN_FILENO) { 114 (void)dup2(pdes[0], STDIN_FILENO); 115 (void)close(pdes[0]); 116 } 117 } 118 execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL); 119 _exit(127); 120 /* NOTREACHED */ 121 } 122 } 123 124 /* Parent; assume fdopen can't fail. */ 125 if (*type == 'r') { 126 iop = fdopen(pdes[0], type); 127 (void)close(pdes[1]); 128 } else { 129 iop = fdopen(pdes[1], type); 130 (void)close(pdes[0]); 131 } 132 133 /* Link into list of file descriptors. */ 134 cur->fp = iop; 135 cur->pid = pid; 136 cur->next = pidlist; 137 pidlist = cur; 138 139 return (iop); 140 } 141 142 /* 143 * pclose -- 144 * Pclose returns -1 if stream is not associated with a `popened' command, 145 * if already `pclosed', or waitpid returns an error. 146 */ 147 int 148 pclose(iop) 149 FILE *iop; 150 { 151 register struct pid *cur, *last; 152 int pstat; 153 pid_t pid; 154 155 (void)fclose(iop); 156 157 /* Find the appropriate file pointer. */ 158 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 159 if (cur->fp == iop) 160 break; 161 if (cur == NULL) 162 return (-1); 163 164 do { 165 pid = waitpid(cur->pid, &pstat, 0); 166 } while (pid == -1 && errno == EINTR); 167 168 /* Remove the entry from the linked list. */ 169 if (last == NULL) 170 pidlist = cur->next; 171 else 172 last->next = cur->next; 173 free(cur); 174 175 return (pid == -1 ? -1 : pstat); 176 } 177