src/unix/map.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #include <git2/common.h>
   8
   9 #if !defined(GIT_WIN32) && !defined(NO_MMAP)
  10
  11 #include "map.h"
  12 #include <sys/mman.h>
  13 #include <unistd.h>
  14 #include <errno.h>
  15
  16 int git__page_size(size_t *page_size)
  17 {
  18         long sc_page_size = sysconf(_SC_PAGE_SIZE);
  19         if (sc_page_size < 0) {
  20                 giterr_set_str(GITERR_OS, "Can't determine system page size");
  21                 return -1;
  22         }
  23         *page_size = (size_t) sc_page_size;
  24         return 0;
  25 }
  26
  27 int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset)
  28 {
  29         int mprot = PROT_READ;
  30         int mflag = 0;
  31
  32         GIT_MMAP_VALIDATE(out, len, prot, flags);
  33
  34         out->data = NULL;
  35         out->len = 0;
  36
  37         if (prot & GIT_PROT_WRITE)
  38                 mprot |= PROT_WRITE;
  39
  40         if ((flags & GIT_MAP_TYPE) == GIT_MAP_SHARED)
  41                 mflag = MAP_SHARED;
  42         else if ((flags & GIT_MAP_TYPE) == GIT_MAP_PRIVATE)
  43                 mflag = MAP_PRIVATE;
  44         else
  45                 mflag = MAP_SHARED;
  46
  47         out->data = mmap(NULL, len, mprot, mflag, fd, offset);
  48
  49         if (!out->data || out->data == MAP_FAILED) {
  50                 giterr_set(GITERR_OS, "Failed to mmap. Could not write data");
  51                 return -1;
  52         }
  53
  54         out->len = len;
  55
  56         return 0;
  57 }
  58
  59 int p_munmap(git_map *map)
  60 {
  61         assert(map != NULL);
  62         munmap(map->data, map->len);
  63
  64         return 0;
  65 }
  66
  67 #endif
  68