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