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 8.1 (Berkeley) 6/4/93"; 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 if (*type != 'r' && *type != 'w' || type[1]) 68 return (NULL); 69 70 if ((cur = malloc(sizeof(struct pid))) == NULL) 71 return (NULL); 72 73 if (pipe(pdes) < 0) { 74 (void)free(cur); 75 return (NULL); 76 } 77 78 switch (pid = vfork()) { 79 case -1: /* Error. */ 80 (void)close(pdes[0]); 81 (void)close(pdes[1]); 82 (void)free(cur); 83 return (NULL); 84 /* NOTREACHED */ 85 case 0: /* Child. */ 86 if (*type == 'r') { 87 if (pdes[1] != STDOUT_FILENO) { 88 (void)dup2(pdes[1], STDOUT_FILENO); 89 (void)close(pdes[1]); 90 } 91 (void) close(pdes[0]); 92 } else { 93 if (pdes[0] != STDIN_FILENO) { 94 (void)dup2(pdes[0], STDIN_FILENO); 95 (void)close(pdes[0]); 96 } 97 (void)close(pdes[1]); 98 } 99 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 100 _exit(127); 101 /* NOTREACHED */ 102 } 103 104 /* Parent; assume fdopen can't fail. */ 105 if (*type == 'r') { 106 iop = fdopen(pdes[0], type); 107 (void)close(pdes[1]); 108 } else { 109 iop = fdopen(pdes[1], type); 110 (void)close(pdes[0]); 111 } 112 113 /* Link into list of file descriptors. */ 114 cur->fp = iop; 115 cur->pid = pid; 116 cur->next = pidlist; 117 pidlist = cur; 118 119 return (iop); 120 } 121 122 /* 123 * pclose -- 124 * Pclose returns -1 if stream is not associated with a `popened' command, 125 * if already `pclosed', or waitpid returns an error. 126 */ 127 int 128 pclose(iop) 129 FILE *iop; 130 { 131 register struct pid *cur, *last; 132 int omask; 133 union wait pstat; 134 pid_t pid; 135 136 (void)fclose(iop); 137 138 /* Find the appropriate file pointer. */ 139 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 140 if (cur->fp == iop) 141 break; 142 if (cur == NULL) 143 return (-1); 144 145 /* Get the status of the process. */ 146 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 147 do { 148 pid = waitpid(cur->pid, (int *) &pstat, 0); 149 } while (pid == -1 && errno == EINTR); 150 (void)sigsetmask(omask); 151 152 /* Remove the entry from the linked list. */ 153 if (last == NULL) 154 pidlist = cur->next; 155 else 156 last->next = cur->next; 157 free(cur); 158 159 return (pid == -1 ? -1 : pstat.w_status); 160 } 161