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instr.c revision 1.1 
      1 /*-
      2  * Copyright (c) 1990 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 static char sccsid[] = "@(#)instr.c	5.2 (Berkeley) 2/28/91";
     36 #endif /* not lint */
     37 
     38 #include <sys/types.h>
     39 #include <sys/wait.h>
     40 #include <sys/errno.h>
     41 #include <sys/stat.h>
     42 #include <unistd.h>
     43 #include <stdio.h>
     44 #include <stdlib.h>
     45 #include <string.h>
     46 #include "pathnames.h"
     47 
     48 instructions()
     49 {
     50 	extern int errno;
     51 	struct stat sb;
     52 	union wait pstat;
     53 	pid_t pid;
     54 	char *pager, *path;
     55 
     56 	if (stat(_PATH_INSTR, &sb)) {
     57 		(void)fprintf(stderr, "cribbage: %s: %s.\n", _PATH_INSTR,
     58 		    strerror(errno));
     59 		exit(1);
     60 	}
     61 	switch(pid = vfork()) {
     62 	case -1:
     63 		(void)fprintf(stderr, "cribbage: %s.\n", strerror(errno));
     64 		exit(1);
     65 	case 0:
     66 		if (!(path = getenv("PAGER")))
     67 			path = _PATH_MORE;
     68 		if (pager = rindex(path, '/'))
     69 			++pager;
     70 		pager = path;
     71 		execlp(path, pager, _PATH_INSTR, (char *)NULL);
     72 		(void)fprintf(stderr, "cribbage: %s.\n", strerror(errno));
     73 		_exit(1);
     74 	default:
     75 		do {
     76 			pid = waitpid(pid, (int *)&pstat, 0);
     77 		} while (pid == -1 && errno == EINTR);
     78 		if (pid == -1 || pstat.w_status)
     79 			exit(1);
     80 	}
     81 }
     82