compat/win32mmap.c

   1 #include "../git-compat-util.h"
   2
   3 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
   4 {
   5         HANDLE osfhandle, hmap;
   6         void *temp;
   7         LARGE_INTEGER len;
   8         uint64_t o = offset;
   9         uint32_t l = o & 0xFFFFFFFF;
  10         uint32_t h = (o >> 32) & 0xFFFFFFFF;
  11
  12         osfhandle = (HANDLE)_get_osfhandle(fd);
  13         if (!GetFileSizeEx(osfhandle, &len))
  14                 die("mmap: could not determine filesize");
  15
  16         if ((length + offset) > len.QuadPart)
  17                 length = xsize_t(len.QuadPart - offset);
  18
  19         if (!(flags & MAP_PRIVATE))
  20                 die("Invalid usage of mmap when built with USE_WIN32_MMAP");
  21
  22         hmap = CreateFileMapping(osfhandle, NULL,
  23                 prot == PROT_READ ? PAGE_READONLY : PAGE_WRITECOPY, 0, 0, NULL);
  24
  25         if (!hmap) {
  26                 errno = EINVAL;
  27                 return MAP_FAILED;
  28         }
  29
  30         temp = MapViewOfFileEx(hmap, prot == PROT_READ ?
  31                         FILE_MAP_READ : FILE_MAP_COPY, h, l, length, start);
  32
  33         if (!CloseHandle(hmap))
  34                 warning("unable to close file mapping handle");
  35
  36         if (temp)
  37                 return temp;
  38
  39         errno = GetLastError() == ERROR_COMMITMENT_LIMIT ? EFBIG : EINVAL;
  40         return MAP_FAILED;
  41 }
  42
  43 int git_munmap(void *start, size_t length)
  44 {
  45         return !UnmapViewOfFile(start);
  46 }