deps/lightning/check/protect.c

   1 /*
   2  * Simple test of (un)protecting a code buffer.
   3  */
   4
   5 #include <lightning.h>
   6 #include <stdio.h>
   7 #include <assert.h>
   8
   9 #define MARKER 10
  10
  11 int
  12 main(int argc, char *argv[])
  13 {
  14     jit_state_t          *_jit;
  15     jit_node_t           *load, *label, *ok;
  16     unsigned char        *ptr;
  17     void                (*function)(void);
  18     int                   mmap_prot, mmap_flags;
  19
  20     init_jit(argv[0]);
  21     _jit = jit_new_state();
  22
  23     jit_prolog();
  24
  25     load = jit_movi(JIT_R0, 0);
  26     jit_ldr_c(JIT_R0, JIT_R0);
  27     ok = jit_forward();
  28     jit_patch_at(jit_beqi(JIT_R0, MARKER), ok);
  29     jit_prepare();
  30     jit_pushargi(1);
  31     jit_finishi(exit);
  32     label = jit_indirect();
  33     jit_skip(1);              /* Reserves enough space for a byte.  */
  34     jit_patch_at(load, label);
  35     jit_link(ok);
  36     jit_prepare();
  37     jit_pushargi((jit_word_t)"%s\n");
  38     jit_ellipsis();
  39     jit_pushargi((jit_word_t)"ok");
  40     jit_finishi(printf);
  41
  42     function = jit_emit();
  43     if (function == NULL)
  44         abort();
  45
  46     jit_unprotect ();
  47     ptr = jit_address (label);
  48     *ptr = MARKER;
  49     jit_protect ();
  50
  51     jit_clear_state();
  52
  53     (*function)();
  54
  55     jit_destroy_state();
  56     finish_jit();
  57
  58     return (0);
  59 }