1 /* 2 * Copyright (c) 1988 The Regents of the University of California. 3 * 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 = "from: @(#)popen.c 5.15 (Berkeley) 2/23/91";*/ 39 static char *rcsid = "$Id: popen.c,v 1.6 1993/11/11 19:04:30 jtc Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <sys/param.h> 43 #include <sys/wait.h> 44 #include <errno.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include <paths.h> 50 51 static pid_t *pids; 52 53 FILE * 54 popen(command, type) 55 const char *command; 56 const char *type; 57 { 58 FILE *iop; 59 int pdes[2], fds, pid; 60 61 if (*type != 'r' && *type != 'w' || type[1]) { 62 errno = EINVAL; 63 return (NULL); 64 } 65 66 if (pids == NULL) { 67 if ((fds = getdtablesize()) <= 0) 68 return (NULL); 69 if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL) 70 return (NULL); 71 bzero((char *)pids, fds * sizeof(pid_t)); 72 } 73 if (pipe(pdes) < 0) 74 return (NULL); 75 switch (pid = vfork()) { 76 case -1: /* error */ 77 (void) close(pdes[0]); 78 (void) close(pdes[1]); 79 return (NULL); 80 /* NOTREACHED */ 81 case 0: /* child */ 82 if (*type == 'r') { 83 if (pdes[1] != STDOUT_FILENO) { 84 (void) dup2(pdes[1], STDOUT_FILENO); 85 (void) close(pdes[1]); 86 } 87 (void) close(pdes[0]); 88 } else { 89 if (pdes[0] != STDIN_FILENO) { 90 (void) dup2(pdes[0], STDIN_FILENO); 91 (void) close(pdes[0]); 92 } 93 (void) close(pdes[1]); 94 } 95 execl(_PATH_BSHELL, "sh", "-c", command, (char *) 0); 96 _exit(127); 97 /* NOTREACHED */ 98 } 99 /* parent; assume fdopen can't fail... */ 100 if (*type == 'r') { 101 iop = fdopen(pdes[0], type); 102 (void) close(pdes[1]); 103 } else { 104 iop = fdopen(pdes[1], type); 105 (void) close(pdes[0]); 106 } 107 pids[fileno(iop)] = pid; 108 return (iop); 109 } 110 111 int 112 pclose(iop) 113 FILE *iop; 114 { 115 register int fdes; 116 int pstat; 117 pid_t pid; 118 119 /* 120 * pclose returns -1 if stream is not associated with a 121 * `popened' command, if already `pclosed', or waitpid 122 * returns an error. 123 */ 124 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 125 return (-1); 126 (void) fclose(iop); 127 do { 128 pid = waitpid(pids[fdes], &pstat, 0); 129 } while (pid == -1 && errno == EINTR); 130 pids[fdes] = 0; 131 return (pid == -1 ? -1 : pstat); 132 } 133