qemu/tests/qtest/fuzz/fork_fuzz.c
Alexander Bulekov dda2f556c3 fuzz: do not use POSIX shm for coverage bitmap
We used shm_open with mmap to share libfuzzer's coverage bitmap with
child (runner) processes. The same functionality can be achieved with
MAP_SHARED | MAP_ANONYMOUS, since we do not care about naming or
permissioning the shared memory object.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200622165040.15121-1-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-07-06 07:37:02 +02:00

42 lines
1.1 KiB
C

/*
* Fork-based fuzzing helpers
*
* Copyright Red Hat Inc., 2019
*
* Authors:
* Alexander Bulekov <alxndr@bu.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "fork_fuzz.h"
void counter_shm_init(void)
{
/* Copy what's in the counter region to a temporary buffer.. */
void *copy = malloc(&__FUZZ_COUNTERS_END - &__FUZZ_COUNTERS_START);
memcpy(copy,
&__FUZZ_COUNTERS_START,
&__FUZZ_COUNTERS_END - &__FUZZ_COUNTERS_START);
/* Map a shared region over the counter region */
if (mmap(&__FUZZ_COUNTERS_START,
&__FUZZ_COUNTERS_END - &__FUZZ_COUNTERS_START,
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED | MAP_ANONYMOUS,
0, 0) == MAP_FAILED) {
perror("Error: ");
exit(1);
}
/* Copy the original data back to the counter-region */
memcpy(&__FUZZ_COUNTERS_START, copy,
&__FUZZ_COUNTERS_END - &__FUZZ_COUNTERS_START);
free(copy);
}