compat/mmap-blob.c

   1 #include <sys/mman.h>
   2 #include <sys/types.h>
   3
   4 /*
   5  * Allow old BSD naming too, it would be a pity to have to make a
   6  * separate file just for this.
   7  */
   8 #ifndef MAP_ANONYMOUS
   9 #define MAP_ANONYMOUS MAP_ANON
  10 #endif
  11
  12 /*
  13  * Our blob allocator enforces the strict CHUNK size
  14  * requirement, as a portability check.
  15  */
  16 void *blob_alloc(unsigned long size)
  17 {
  18         void *ptr;
  19
  20         if (size & ~CHUNK)
  21                 die("internal error: bad allocation size (%lu bytes)", size);
  22         ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  23         if (ptr == MAP_FAILED)
  24                 ptr = NULL;
  25         return ptr;
  26 }
  27
  28 void blob_free(void *addr, unsigned long size)
  29 {
  30         if (!size || (size & ~CHUNK) || ((unsigned long) addr & 512))
  31                 die("internal error: bad blob free (%lu bytes at %p)", size, addr);
  32 #ifndef DEBUG
  33         munmap(addr, size);
  34 #else
  35         mprotect(addr, size, PROT_NONE);
  36 #endif
  37 }