memcheck/tests/linux/stack_changes.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <ucontext.h>
   4 #include "tests/sys_mman.h"
   5
   6 #include "valgrind.h"
   7
   8 #define STACK_SIZE (10 * 4096)
   9
  10 // This test is checking the libc context calls (setcontext, etc.) and
  11 // checks that Valgrind notices their stack changes properly.
  12
  13 typedef  ucontext_t  mycontext;
  14
  15 mycontext ctx1, ctx2, oldc;
  16 int count;
  17
  18 void hello(mycontext *newc)
  19 {
  20     printf("hello, world: %d\n", count);
  21     if (count++ == 2)
  22         newc = &oldc;
  23     setcontext(newc);
  24 }
  25
  26 int init_context(mycontext *uc)
  27 {
  28     void *stack;
  29     int ret;
  30
  31     if (getcontext(uc) == -1) {
  32         //perror("getcontext");
  33         printf("getcontext() doesn't seem to work\n");
  34         exit(1);
  35     }
  36
  37     stack = (void *)mmap(0, STACK_SIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
  38                                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
  39
  40     if (stack == (void*)-1) {
  41         perror("mmap");
  42         exit(1);
  43     }
  44
  45     ret = VALGRIND_STACK_REGISTER(stack, stack + STACK_SIZE);
  46
  47     uc->uc_link = NULL;
  48     uc->uc_stack.ss_sp = stack;
  49     uc->uc_stack.ss_size = STACK_SIZE;
  50     uc->uc_stack.ss_flags = 0;
  51
  52     return ret;
  53 }
  54
  55 int main(int argc, char **argv)
  56 {
  57     int c1 = init_context(&ctx1);
  58     int c2 = init_context(&ctx2);
  59
  60     makecontext(&ctx1, (void (*)()) hello, 1, &ctx2);
  61     makecontext(&ctx2, (void (*)()) hello, 1, &ctx1);
  62
  63     swapcontext(&oldc, &ctx1);
  64
  65     VALGRIND_STACK_DEREGISTER(c1);
  66     //free(ctx1.uc_stack.ss_sp);
  67     VALGRIND_STACK_DEREGISTER(c2);
  68     //free(ctx2.uc_stack.ss_sp);
  69
  70     return 0;
  71 }