cribbage/instr.c

   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 }