/* * Test that allocating a variable length array in a loop * does not use up a linear amount of memory */ #include <stdlib.h>#include <stdio.h>#include <string.h> #define LOOP_COUNT 1000#define ARRAY_SIZE 100 /* Overwrite a VLA. This will overwrite the return address if SP is incorrect */void smash(char *p, int n) {  memset(p, 0, n);} int test1(int n) {  int i;  char *array_ptrs[LOOP_COUNT];    for (i = 0; i < LOOP_COUNT; ++i) {    char test[n];    smash(test, n);    array_ptrs[i] = test;  }    return (array_ptrs[0]-array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1;} /* ensure goto does not circumvent array free */int test2(int n) {  char *array_ptrs[LOOP_COUNT];   int i = 0;loop:;  char test[n];  smash(test, n);  if (i >= LOOP_COUNT)    goto end;  array_ptrs[i] = test;  ++i;  goto loop; end:  smash(test, n);  char test2[n];  smash(test2, n);  return (array_ptrs[0] - array_ptrs[LOOP_COUNT-1] < n) ? 0 : 1;} int test3(int n) {  char test[n];  smash(test, n);  goto label;label:  smash(test, n);  char test2[n];  smash(test2, n);  return (test-test2 >= n) ? 0 : 1;} #define RUN_TEST(t) \  if (!testname || (strcmp(#t, testname) == 0)) { \    fputs(#t "... ", stdout); \    fflush(stdout); \    if (t(ARRAY_SIZE) == 0) { \      fputs("success\n", stdout); \    } else { \      fputs("failure\n", stdout); \      retval = EXIT_FAILURE; \    } \  } int main(int argc, char **argv) {  const char *testname = NULL;  int retval = EXIT_SUCCESS;  if (argc > 1)    testname = argv[1];  RUN_TEST(test1)  RUN_TEST(test2)  RUN_TEST(test3)  return retval;}