syscalls/munmap.c

   1 /*
   2  * SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
   3  */
   4 #include <stdlib.h>
   5 #include "arch.h"
   6 #include "maps.h"
   7 #include "random.h"
   8 #include "sanitise.h"
   9 #include "shm.h"
  10
  11 #define WHOLE 1
  12 static int action;
  13
  14 static void sanitise_munmap(int childno)
  15 {
  16         struct map *map;
  17         unsigned long len;
  18         unsigned long nr_pages;
  19         unsigned long offset, offsetpagenr;
  20
  21         map = common_set_mmap_ptr_len(childno);
  22
  23         action = 0;
  24
  25         switch (rand() % 20) {
  26         case 0:
  27                 /* delete the whole mapping. */
  28                 action = WHOLE;
  29                 return;
  30
  31         case 1 ... 10:
  32                 /* unmap a range of the mapping. */
  33                 nr_pages = map->size / page_size;
  34                 offsetpagenr = (rand() % nr_pages);
  35                 offset = offsetpagenr * page_size;
  36                 shm->syscall[childno].a1 = (unsigned long) map->ptr + offset;
  37
  38                 len = (rand() % (nr_pages - offsetpagenr)) + 1;
  39                 len *= page_size;
  40                 shm->syscall[childno].a2 = len;
  41                 return;
  42
  43         case 11 ... 19:
  44                 /* just unmap 1 page of the mapping. */
  45                 shm->syscall[childno].a1 = (unsigned long) map->ptr;
  46                 shm->syscall[childno].a1 += (rand() % map->size) & PAGE_MASK;
  47                 shm->syscall[childno].a2 = page_size;
  48                 return;
  49
  50         default:
  51                 break;
  52         }
  53 }
  54
  55 static void post_munmap(int childno)
  56 {
  57         struct map *map = (struct map *) shm->scratch[childno];
  58
  59         if (shm->syscall[childno].retval != 0)
  60                 return;
  61
  62         if (action == WHOLE)
  63                 delete_mapping(childno, map);
  64
  65         shm->scratch[childno] = 0;
  66 }
  67
  68 struct syscallentry syscall_munmap = {
  69         .name = "munmap",
  70         .num_args = 2,
  71         .arg1name = "addr",
  72         .arg1type = ARG_MMAP,
  73         .arg2name = "len",
  74         .group = GROUP_VM,
  75         .sanitise = sanitise_munmap,
  76         .post = post_munmap,
  77 };