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      1 /*	$NetBSD: instr.c,v 1.14 2011/09/01 07:18:50 plunky Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)instr.c	8.1 (Berkeley) 5/31/93";
     36 #else
     37 __RCSID("$NetBSD: instr.c,v 1.14 2011/09/01 07:18:50 plunky Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include <sys/types.h>
     42 #include <sys/wait.h>
     43 #include <sys/stat.h>
     44 
     45 #include <curses.h>
     46 #include <err.h>
     47 #include <fcntl.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 #include <unistd.h>
     52 #include <errno.h>
     53 
     54 #include "deck.h"
     55 #include "cribbage.h"
     56 #include "pathnames.h"
     57 
     58 void
     59 instructions(void)
     60 {
     61 	int pstat;
     62 	int fd;
     63 	pid_t pid;
     64 	const char *path;
     65 
     66 	switch (pid = vfork()) {
     67 	case -1:
     68 		err(1, "vfork");
     69 	case 0:
     70 		/* Follow the same behaviour for pagers as defined in POSIX.2
     71 		 * for mailx and man.  We only use a pager if stdout is
     72 		 * a terminal, and we pass the file on stdin to sh -c pager.
     73 		 */
     74 		if (!isatty(1))
     75 			path = "cat";
     76 		else {
     77 			if (!(path = getenv("PAGER")) || (*path == 0))
     78 				path = _PATH_MORE;
     79 		}
     80 		if ((fd = open(_PATH_INSTR, O_RDONLY)) == -1) {
     81 			warn("open %s", _PATH_INSTR);
     82 			_exit(1);
     83 		}
     84 		if (dup2(fd, 0) == -1) {
     85 			warn("dup2");
     86 			_exit(1);
     87 		}
     88 		execl("/bin/sh", "sh", "-c", path, (char *) NULL);
     89 		warn(NULL);
     90 		_exit(1);
     91 	default:
     92 		do {
     93 			pid = waitpid(pid, &pstat, 0);
     94 		} while (pid == -1 && errno == EINTR);
     95 		if (pid == -1 || WEXITSTATUS(pstat))
     96 			exit(1);
     97 	}
     98 }
     99