compat/mmap.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include "../cache.h"
   6
   7 void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset)
   8 {
   9         int n = 0;
  10
  11         if (start != NULL || !(flags & MAP_PRIVATE))
  12                 die("Invalid usage of gitfakemmap.");
  13
  14         if (lseek(fd, offset, SEEK_SET) < 0) {
  15                 errno = EINVAL;
  16                 return MAP_FAILED;
  17         }
  18
  19         start = xmalloc(length);
  20         if (start == NULL) {
  21                 errno = ENOMEM;
  22                 return MAP_FAILED;
  23         }
  24
  25         while (n < length) {
  26                 int count = read(fd, start+n, length-n);
  27
  28                 if (count == 0) {
  29                         memset(start+n, 0, length-n);
  30                         break;
  31                 }
  32
  33                 if (count < 0) {
  34                         free(start);
  35                         errno = EACCES;
  36                         return MAP_FAILED;
  37                 }
  38
  39                 n += count;
  40         }
  41
  42         return start;
  43 }
  44
  45 int gitfakemunmap(void *start, size_t length)
  46 {
  47         free(start);
  48         return 0;
  49 }
  50