src/libs/libbib/map.c

   1 /* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2001, 2004
   2    Free Software Foundation, Inc.
   3      Written by James Clark (jjc@jclark.com)
   4
   5 This file is part of groff.
   6
   7 groff is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License along
  18 with groff; see the file COPYING.  If not, write to the Free Software
  19 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  20
  21 #include <stdlib.h>
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #ifdef HAVE_MMAP
  28
  29 #include <sys/types.h>
  30 #include <sys/mman.h>
  31
  32 /* The Net-2 man pages says that a MAP_FILE flag is required. */
  33 #ifndef MAP_FILE
  34 #define MAP_FILE 0
  35 #endif
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 char *mapread(int fd, int nbytes)
  42 {
  43   char *p = (char *)mmap((void *)0, (size_t)nbytes, PROT_READ,
  44                          MAP_FILE|MAP_PRIVATE, fd, (off_t)0);
  45   if (p == (char *)-1)
  46     return 0;
  47   /* mmap() shouldn't return 0 since MAP_FIXED wasn't specified. */
  48   if (p == 0)
  49     abort();
  50   return p;
  51 }
  52
  53 int unmap(char *p, int len)
  54 {
  55   return munmap((void *)p, len);
  56 }
  57
  58 #ifdef __cplusplus
  59 }
  60 #endif
  61
  62 #else /* not HAVE_MMAP */
  63
  64 #include <errno.h>
  65
  66 #ifdef __cplusplus
  67 extern "C" {
  68 #endif
  69
  70 char *mapread(int fd, int nbytes)
  71 {
  72   errno = ENODEV;
  73   return 0;
  74 }
  75
  76 int unmap(char *p, int len)
  77 {
  78   errno = EINVAL;
  79   return -1;
  80 }
  81
  82 #ifdef __cplusplus
  83 }
  84 #endif
  85
  86 #endif /* not HAVE_MMAP */