compat/mmap.c

   1 #include "../git-compat-util.h"
   2
   3 void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset)
   4 {
   5         int n = 0;
   6         off_t current_offset = lseek(fd, 0, SEEK_CUR);
   7
   8         if (start != NULL || !(flags & MAP_PRIVATE))
   9                 die("Invalid usage of gitfakemmap.");
  10
  11         if (lseek(fd, offset, SEEK_SET) < 0) {
  12                 errno = EINVAL;
  13                 return MAP_FAILED;
  14         }
  15
  16         start = xmalloc(length);
  17         if (start == NULL) {
  18                 errno = ENOMEM;
  19                 return MAP_FAILED;
  20         }
  21
  22         while (n < length) {
  23                 int count = read(fd, start+n, length-n);
  24
  25                 if (count == 0) {
  26                         memset(start+n, 0, length-n);
  27                         break;
  28                 }
  29
  30                 if (count < 0) {
  31                         free(start);
  32                         errno = EACCES;
  33                         return MAP_FAILED;
  34                 }
  35
  36                 n += count;
  37         }
  38
  39         if (current_offset != lseek(fd, current_offset, SEEK_SET)) {
  40                 errno = EINVAL;
  41                 return MAP_FAILED;
  42         }
  43
  44         return start;
  45 }
  46
  47 int gitfakemunmap(void *start, size_t length)
  48 {
  49         free(start);
  50         return 0;
  51 }
  52