compat/mmap.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include "../git-compat-util.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         off_t current_offset = lseek(fd, 0, SEEK_CUR);
  11
  12         if (start != NULL || !(flags & MAP_PRIVATE))
  13                 die("Invalid usage of gitfakemmap.");
  14
  15         if (lseek(fd, offset, SEEK_SET) < 0) {
  16                 errno = EINVAL;
  17                 return MAP_FAILED;
  18         }
  19
  20         start = xmalloc(length);
  21         if (start == NULL) {
  22                 errno = ENOMEM;
  23                 return MAP_FAILED;
  24         }
  25
  26         while (n < length) {
  27                 int count = read(fd, start+n, length-n);
  28
  29                 if (count == 0) {
  30                         memset(start+n, 0, length-n);
  31                         break;
  32                 }
  33
  34                 if (count < 0) {
  35                         free(start);
  36                         errno = EACCES;
  37                         return MAP_FAILED;
  38                 }
  39
  40                 n += count;
  41         }
  42
  43         if (current_offset != lseek(fd, current_offset, SEEK_SET)) {
  44                 errno = EINVAL;
  45                 return MAP_FAILED;
  46         }
  47
  48         return start;
  49 }
  50
  51 int gitfakemunmap(void *start, size_t length)
  52 {
  53         free(start);
  54         return 0;
  55 }
  56