shm.c

   1 /*
   2  * Shared mapping creation.
   3  */
   4
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <sys/mman.h>
   9 #include "arch.h"
  10 #include "child.h"
  11 #include "log.h"
  12 #include "params.h"
  13 #include "pids.h"
  14 #include "random.h"
  15 #include "shm.h"
  16 #include "utils.h"
  17
  18 struct shm_s *shm;
  19
  20 #define SHM_PROT_PAGES 30
  21
  22 void create_shm(void)
  23 {
  24         void *p;
  25         unsigned int shm_pages;
  26
  27         /* round up shm to nearest page size */
  28         shm_pages = ((sizeof(struct shm_s) + page_size - 1) & ~(page_size - 1)) / page_size;
  29
  30         /* Waste some address space to set up some "protection" near the SHM location. */
  31         p = alloc_shared((SHM_PROT_PAGES + shm_pages + SHM_PROT_PAGES) * page_size);
  32
  33         /* clear whole mapping, including the redzones. */
  34         memset(p, 0, shm_pages * page_size);
  35
  36         /* set the redzones to PROT_NONE */
  37         mprotect(p, SHM_PROT_PAGES * page_size, PROT_NONE);
  38         mprotect(p + (SHM_PROT_PAGES + shm_pages) * page_size,
  39                         SHM_PROT_PAGES * page_size, PROT_NONE);
  40
  41         shm = p + SHM_PROT_PAGES * page_size;
  42 }
  43
  44 void create_shm_arrays(void)
  45 {
  46         shm->child_op_count = alloc_shared(max_children * sizeof(unsigned long));
  47
  48         shm->pids = alloc_shared(max_children * sizeof(pid_t));
  49
  50         shm->tv = alloc_shared(max_children * sizeof(struct timeval));
  51
  52         shm->syscall = alloc_shared(max_children * sizeof(struct syscallrecord));
  53         shm->previous = alloc_shared(max_children * sizeof(struct syscallrecord));
  54
  55         shm->mappings = alloc_shared(max_children * sizeof(struct map *));
  56         shm->num_mappings = alloc_shared(max_children * sizeof(unsigned int));
  57
  58         shm->seeds = alloc_shared(max_children * sizeof(int));
  59         shm->kill_count = alloc_shared(max_children * sizeof(unsigned char));
  60         shm->logfiles = alloc_shared(max_children * sizeof(FILE *));
  61         shm->scratch = alloc_shared(max_children * sizeof(unsigned long));
  62 }
  63
  64 void init_shm(void)
  65 {
  66         unsigned int i;
  67
  68         output(2, "shm is at %p\n", shm);
  69
  70         shm->total_syscalls_done = 1;
  71
  72         if (user_set_seed == TRUE)
  73                 shm->seed = init_seed(seed);
  74         else
  75                 shm->seed = new_seed();
  76         /* Set seed in parent thread */
  77         set_seed(0);
  78
  79         for (i = 0; i < max_children; i++) {
  80
  81                 shm->pids[i] = EMPTY_PIDSLOT;
  82
  83                 shm->previous[i].nr = shm->syscall[i].nr = -1;
  84
  85                 shm->previous[i].a1 = shm->syscall[i].a1 = -1;
  86                 shm->previous[i].a2 = shm->syscall[i].a2 = -1;
  87                 shm->previous[i].a3 = shm->syscall[i].a3 = -1;
  88                 shm->previous[i].a4 = shm->syscall[i].a4 = -1;
  89                 shm->previous[i].a5 = shm->syscall[i].a5 = -1;
  90                 shm->previous[i].a6 = shm->syscall[i].a6 = -1;
  91         }
  92 }