maps-static.c

   1 #include <malloc.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include "arch.h"
   5 #include "log.h"
   6 #include "maps.h"
   7 #include "random.h"
   8 #include "utils.h"
   9
  10 /* "static" pages. */
  11 char *page_zeros;
  12 char *page_0xff;
  13 char *page_rand;
  14 unsigned long *page_allocs;
  15 unsigned long *page_maps;
  16
  17 static void * __allocbuf(const char *name)
  18 {
  19         void *ptr;
  20
  21         ptr = memalign(page_size, page_size * 2);
  22         if (!ptr)
  23                 exit(EXIT_FAILURE);
  24         output(2, "%s @ %p\n", name, ptr);
  25         return ptr;
  26 }
  27
  28 void init_shared_pages(void)
  29 {
  30         unsigned int i;
  31
  32         // a page of zeros
  33         page_zeros = __allocbuf("page_zeros");
  34         memset(page_zeros, 0, page_size * 2);
  35
  36         // a page of 0xff
  37         page_0xff = __allocbuf("page_0xff");
  38         memset(page_0xff, 0xff, page_size * 2);
  39
  40         // a page of random crap (overwritten below)
  41         page_rand = __allocbuf("page_rand");
  42
  43         // page containing ptrs to mallocs.
  44         page_allocs = __allocbuf("page_allocs");
  45         for (i = 0; i < (page_size / sizeof(unsigned long *)); i++)
  46                 page_allocs[i] = (unsigned long) malloc(page_size);
  47
  48         // a page of ptrs to mmaps (set up at child init time).
  49         page_maps = __allocbuf("page_maps");
  50
  51         // mmaps that get shared across children.
  52         setup_shared_mappings();
  53
  54         // generate_random_page may end up using shared_mappings, so has to be last.
  55         generate_random_page(page_rand);
  56 }