1 /* $OpenBSD: instr.c,v 1.14 2016/01/10 13:35:09 mestre Exp $ */ 2 /* $NetBSD: instr.c,v 1.5 1997/07/10 06:47:30 mikel Exp $ */ 3 4 /*- 5 * Copyright (c) 1990, 1993 6 * The Regents of the University of California. All rights reserved. 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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/wait.h> 34 35 #include <err.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <paths.h> 39 #include <stdlib.h> 40 #include <unistd.h> 41 42 #include "pathnames.h" 43 44 void 45 instructions(void) 46 { 47 int pstat; 48 int fd; 49 pid_t pid; 50 const char *pager; 51 52 if ((fd = open(_PATH_INSTR, O_RDONLY)) == - 1) 53 errx(1, "can't open %s", _PATH_INSTR); 54 55 switch (pid = vfork()) { 56 case -1: 57 err(1, "vfork"); 58 case 0: 59 if (!isatty(1)) 60 pager = "/bin/cat"; 61 else { 62 if (!(pager = getenv("PAGER")) || (*pager == 0)) 63 pager = _PATH_MORE; 64 } 65 if (dup2(fd, 0) == -1) 66 err(1, "dup2"); 67 execl(_PATH_BSHELL, "sh", "-c", pager, (char *)NULL); 68 err(1, "exec sh -c %s", pager); 69 default: 70 do { 71 pid = waitpid(pid, &pstat, 0); 72 } while (pid == -1 && errno == EINTR); 73 close(fd); 74 if (pid == -1 || WEXITSTATUS(pstat)) 75 exit(1); 76 break; 77 } 78 } 79