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/* Reproduce a GNU malloc bug. */
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#define size_t unsigned int
/* Defined as global variables to avoid warnings about unused variables. */
char *dummy0;
char *dummy1;
char *fill_info_table1;
int
main (int argc, char *argv[])
{
char *over_top;
size_t over_top_size = 0x3000;
char *over_top_dup;
size_t over_top_dup_size = 0x7000;
char *x;
size_t i;
/* Here's what memory is supposed to look like (hex):
size contents
3000 original_info_table, later fill_info_table1
3fa000 dummy0
3fa000 dummy1
6000 info_table_2
3000 over_top
*/
/* mem: original_info_table */
dummy0 = malloc (0x3fa000);
/* mem: original_info_table, dummy0 */
dummy1 = malloc (0x3fa000);
/* mem: free, dummy0, dummy1, info_table_2 */
fill_info_table1 = malloc (0x3000);
/* mem: fill_info_table1, dummy0, dummy1, info_table_2 */
x = malloc (0x1000);
free (x);
/* mem: fill_info_table1, dummy0, dummy1, info_table_2, freexx */
/* This is what loses; info_table_2 and freexx get combined unbeknownst
to mmalloc, and mmalloc puts over_top in a section of memory which
is on the free list as part of another block (where info_table_2 had
been). */
over_top = malloc (over_top_size);
over_top_dup = malloc (over_top_dup_size);
memset (over_top, 0, over_top_size);
memset (over_top_dup, 1, over_top_dup_size);
for (i = 0; i < over_top_size; ++i)
if (over_top[i] != 0)
{
printf ("FAIL: malloc expands info table\n");
return 0;
}
for (i = 0; i < over_top_dup_size; ++i)
if (over_top_dup[i] != 1)
{
printf ("FAIL: malloc expands info table\n");
return 0;
}
printf ("PASS: malloc expands info table\n");
return 0;
}
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