OVMS3/OVMS.V3/components/ovms_script/umm/umm_integrity.c

129 lines
4 KiB
C

/* integrity check (UMM_INTEGRITY_CHECK) {{{ */
#ifdef UMM_INTEGRITY_CHECK
#include <stdint.h>
#include <stdbool.h>
/*
* Perform integrity check of the whole heap data. Returns 1 in case of
* success, 0 otherwise.
*
* First of all, iterate through all free blocks, and check that all backlinks
* match (i.e. if block X has next free block Y, then the block Y should have
* previous free block set to X).
*
* Additionally, we check that each free block is correctly marked with
* `UMM_FREELIST_MASK` on the `next` pointer: during iteration through free
* list, we mark each free block by the same flag `UMM_FREELIST_MASK`, but
* on `prev` pointer. We'll check and unmark it later.
*
* Then, we iterate through all blocks in the heap, and similarly check that
* all backlinks match (i.e. if block X has next block Y, then the block Y
* should have previous block set to X).
*
* But before checking each backlink, we check that the `next` and `prev`
* pointers are both marked with `UMM_FREELIST_MASK`, or both unmarked.
* This way, we ensure that the free flag is in sync with the free pointers
* chain.
*/
bool umm_integrity_check(void) {
bool ok = true;
uint16_t prev;
uint16_t cur;
UMM_CHECK_INITIALIZED();
/* Iterate through all free blocks */
prev = 0;
while (1) {
cur = UMM_NFREE(prev);
/* Check that next free block number is valid */
if (cur >= UMM_NUMBLOCKS) {
DBGLOG_CRITICAL("Heap integrity broken: too large next free num: %d "
"(in block %d, addr 0x%08x)\n",
cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
ok = false;
goto clean;
}
if (cur == 0) {
/* No more free blocks */
break;
}
/* Check if prev free block number matches */
if (UMM_PFREE(cur) != prev) {
DBGLOG_CRITICAL("Heap integrity broken: free links don't match: "
"%d -> %d, but %d -> %d\n",
prev, cur, cur, UMM_PFREE(cur));
ok = false;
goto clean;
}
UMM_PBLOCK(cur) |= UMM_FREELIST_MASK;
prev = cur;
}
/* Iterate through all blocks */
prev = 0;
while (1) {
cur = UMM_NBLOCK(prev) & UMM_BLOCKNO_MASK;
/* Check that next block number is valid */
if (cur >= UMM_NUMBLOCKS) {
DBGLOG_CRITICAL("Heap integrity broken: too large next block num: %d "
"(in block %d, addr 0x%08x)\n",
cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
ok = false;
goto clean;
}
if (cur == 0) {
/* No more blocks */
break;
}
/* make sure the free mark is appropriate, and unmark it */
if ((UMM_NBLOCK(cur) & UMM_FREELIST_MASK)
!= (UMM_PBLOCK(cur) & UMM_FREELIST_MASK)) {
DBGLOG_CRITICAL("Heap integrity broken: mask wrong at addr 0x%08x: n=0x%x, p=0x%x\n",
DBGLOG_32_BIT_PTR(&UMM_NBLOCK(cur)),
(UMM_NBLOCK(cur) & UMM_FREELIST_MASK),
(UMM_PBLOCK(cur) & UMM_FREELIST_MASK));
ok = false;
goto clean;
}
/* make sure the block list is sequential */
if (cur <= prev) {
DBGLOG_CRITICAL("Heap integrity broken: next block %d is before prev this one "
"(in block %d, addr 0x%08x)\n",
cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
ok = false;
goto clean;
}
/* unmark */
UMM_PBLOCK(cur) &= UMM_BLOCKNO_MASK;
/* Check if prev block number matches */
if (UMM_PBLOCK(cur) != prev) {
DBGLOG_CRITICAL("Heap integrity broken: block links don't match: "
"%d -> %d, but %d -> %d\n",
prev, cur, cur, UMM_PBLOCK(cur));
ok = false;
goto clean;
}
prev = cur;
}
clean:
if (!ok) {
UMM_HEAP_CORRUPTION_CB();
}
return ok;
}
#endif
/* }}} */