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 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <sys/param.h> 45 #include <sys/wait.h> 46 47 #include <signal.h> 48 #include <errno.h> 49 #include <unistd.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <paths.h> 54 #include "un-namespace.h" 55 56 extern char **environ; 57 58 static struct pid { 59 struct pid *next; 60 FILE *fp; 61 pid_t pid; 62 } *pidlist; 63 64 FILE * 65 popen(command, type) 66 const char *command, *type; 67 { 68 struct pid *cur; 69 FILE *iop; 70 int pdes[2], pid, twoway; 71 char *argv[4]; 72 struct pid *p; 73 74 /* 75 * Lite2 introduced two-way popen() pipes using _socketpair(). 76 * FreeBSD's pipe() is bidirectional, so we use that. 77 */ 78 if (strchr(type, '+')) { 79 twoway = 1; 80 type = "r+"; 81 } else { 82 twoway = 0; 83 if ((*type != 'r' && *type != 'w') || type[1]) 84 return (NULL); 85 } 86 if (pipe(pdes) < 0) 87 return (NULL); 88 89 if ((cur = malloc(sizeof(struct pid))) == NULL) { 90 (void)_close(pdes[0]); 91 (void)_close(pdes[1]); 92 return (NULL); 93 } 94 95 argv[0] = "sh"; 96 argv[1] = "-c"; 97 argv[2] = (char *)command; 98 argv[3] = NULL; 99 100 switch (pid = vfork()) { 101 case -1: /* Error. */ 102 (void)_close(pdes[0]); 103 (void)_close(pdes[1]); 104 free(cur); 105 return (NULL); 106 /* NOTREACHED */ 107 case 0: /* Child. */ 108 if (*type == 'r') { 109 /* 110 * The _dup2() to STDIN_FILENO is repeated to avoid 111 * writing to pdes[1], which might corrupt the 112 * parent's copy. This isn't good enough in 113 * general, since the _exit() is no return, so 114 * the compiler is free to corrupt all the local 115 * variables. 116 */ 117 (void)_close(pdes[0]); 118 if (pdes[1] != STDOUT_FILENO) { 119 (void)_dup2(pdes[1], STDOUT_FILENO); 120 (void)_close(pdes[1]); 121 if (twoway) 122 (void)_dup2(STDOUT_FILENO, STDIN_FILENO); 123 } else if (twoway && (pdes[1] != STDIN_FILENO)) 124 (void)_dup2(pdes[1], STDIN_FILENO); 125 } else { 126 if (pdes[0] != STDIN_FILENO) { 127 (void)_dup2(pdes[0], STDIN_FILENO); 128 (void)_close(pdes[0]); 129 } 130 (void)_close(pdes[1]); 131 } 132 for (p = pidlist; p; p = p->next) { 133 (void)_close(fileno(p->fp)); 134 } 135 _execve(_PATH_BSHELL, argv, environ); 136 _exit(127); 137 /* NOTREACHED */ 138 } 139 140 /* Parent; assume fdopen can't fail. */ 141 if (*type == 'r') { 142 iop = fdopen(pdes[0], type); 143 (void)_close(pdes[1]); 144 } else { 145 iop = fdopen(pdes[1], type); 146 (void)_close(pdes[0]); 147 } 148 149 /* Link into list of file descriptors. */ 150 cur->fp = iop; 151 cur->pid = pid; 152 cur->next = pidlist; 153 pidlist = cur; 154 155 return (iop); 156 } 157 158 /* 159 * pclose -- 160 * Pclose returns -1 if stream is not associated with a `popened' command, 161 * if already `pclosed', or waitpid returns an error. 162 */ 163 int 164 pclose(iop) 165 FILE *iop; 166 { 167 struct pid *cur, *last; 168 int omask; 169 int pstat; 170 pid_t pid; 171 172 /* Find the appropriate file pointer. */ 173 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 174 if (cur->fp == iop) 175 break; 176 if (cur == NULL) 177 return (-1); 178 179 (void)fclose(iop); 180 181 do { 182 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); 183 } while (pid == -1 && errno == EINTR); 184 185 /* Remove the entry from the linked list. */ 186 if (last == NULL) 187 pidlist = cur->next; 188 else 189 last->next = cur->next; 190 free(cur); 191 192 return (pid == -1 ? -1 : pstat); 193 } 194