compat/win32mmap.c

   1 #include "../git-compat-util.h"
   2
   3 /*
   4  * Note that this doesn't return the actual pagesize, but
   5  * the allocation granularity. If future Windows specific git code
   6  * needs the real getpagesize function, we need to find another solution.
   7  */
   8 int mingw_getpagesize(void)
   9 {
  10         SYSTEM_INFO si;
  11         GetSystemInfo(&si);
  12         return si.dwAllocationGranularity;
  13 }
  14
  15 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
  16 {
  17         HANDLE hmap;
  18         void *temp;
  19         size_t len;
  20         struct stat st;
  21         uint64_t o = offset;
  22         uint32_t l = o & 0xFFFFFFFF;
  23         uint32_t h = (o >> 32) & 0xFFFFFFFF;
  24
  25         if (!fstat(fd, &st))
  26                 len = xsize_t(st.st_size);
  27         else
  28                 die("mmap: could not determine filesize");
  29
  30         if ((length + offset) > len)
  31                 length = len - offset;
  32
  33         if (!(flags & MAP_PRIVATE))
  34                 die("Invalid usage of mmap when built with USE_WIN32_MMAP");
  35
  36         hmap = CreateFileMapping((HANDLE)_get_osfhandle(fd), 0, PAGE_WRITECOPY,
  37                 0, 0, 0);
  38
  39         if (!hmap)
  40                 return MAP_FAILED;
  41
  42         temp = MapViewOfFileEx(hmap, FILE_MAP_COPY, h, l, length, start);
  43
  44         if (!CloseHandle(hmap))
  45                 warning("unable to close file mapping handle\n");
  46
  47         return temp ? temp : MAP_FAILED;
  48 }
  49
  50 int git_munmap(void *start, size_t length)
  51 {
  52         return !UnmapViewOfFile(start);
  53 }