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[] = "@(#)popen.c 5.15 (Berkeley) 2/23/91"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 #include <sys/signal.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(program, type) 55 const char *program; 56 const char *type; 57 { 58 FILE *iop; 59 int pdes[2], fds, pid; 60 61 if (*type != 'r' && *type != 'w' || type[1]) 62 return (NULL); 63 64 if (pids == NULL) { 65 if ((fds = getdtablesize()) <= 0) 66 return (NULL); 67 if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL) 68 return (NULL); 69 bzero((char *)pids, fds * sizeof(pid_t)); 70 } 71 if (pipe(pdes) < 0) 72 return (NULL); 73 switch (pid = vfork()) { 74 case -1: /* error */ 75 (void) close(pdes[0]); 76 (void) close(pdes[1]); 77 return (NULL); 78 /* NOTREACHED */ 79 case 0: /* child */ 80 if (*type == 'r') { 81 if (pdes[1] != STDOUT_FILENO) { 82 (void) dup2(pdes[1], STDOUT_FILENO); 83 (void) close(pdes[1]); 84 } 85 (void) close(pdes[0]); 86 } else { 87 if (pdes[0] != STDIN_FILENO) { 88 (void) dup2(pdes[0], STDIN_FILENO); 89 (void) close(pdes[0]); 90 } 91 (void) close(pdes[1]); 92 } 93 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 94 _exit(127); 95 /* NOTREACHED */ 96 } 97 /* parent; assume fdopen can't fail... */ 98 if (*type == 'r') { 99 iop = fdopen(pdes[0], type); 100 (void) close(pdes[1]); 101 } else { 102 iop = fdopen(pdes[1], type); 103 (void) close(pdes[0]); 104 } 105 pids[fileno(iop)] = pid; 106 return (iop); 107 } 108 109 int 110 pclose(iop) 111 FILE *iop; 112 { 113 register int fdes; 114 int omask; 115 union wait pstat; 116 pid_t pid; 117 118 /* 119 * pclose returns -1 if stream is not associated with a 120 * `popened' command, if already `pclosed', or waitpid 121 * returns an error. 122 */ 123 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 124 return (-1); 125 (void) fclose(iop); 126 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 127 do { 128 pid = waitpid(pids[fdes], (int *) &pstat, 0); 129 } while (pid == -1 && errno == EINTR); 130 (void) sigsetmask(omask); 131 pids[fdes] = 0; 132 return (pid == -1 ? -1 : pstat.w_status); 133 } 134