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hllSparseToDense(): sanity check added.

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The function checks if all the HLL_REGISTERS were processed during the
convertion from sparse to dense encoding, returning REDIS_OK or
REDIS_ERR to signal a corruption problem.

A bug in PFDEBUG GETREG was fixed: when the object is converted to the
dense representation we need to reassign the new pointer to the header
structure pointer.
This commit is contained in:
antirez 2014-04-14 09:27:01 +02:00
parent f9dc3cb04d
commit b7571b7453
1 changed files with 20 additions and 5 deletions
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25
src/hyperloglog.c
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@ -559,8 +559,11 @@ double hllDenseSum(uint8_t *registers, double *PE, int *ezp) {
/* Convert the HLL with sparse representation given as input in its dense /* Convert the HLL with sparse representation given as input in its dense
* representation. Both representations are represented by SDS strings, and * representation. Both representations are represented by SDS strings, and
* the input representation is freed as a side effect. */ * the input representation is freed as a side effect.
void hllSparseToDense(robj *o) { *
* The function returns REDIS_OK if the sparse representation was valid,
* otherwise REDIS_ERR is returned if the representation was corrupted. */
int hllSparseToDense(robj *o) {
sds sparse = o->ptr, dense; sds sparse = o->ptr, dense;
struct hllhdr *hdr, *oldhdr = (struct hllhdr*)sparse; struct hllhdr *hdr, *oldhdr = (struct hllhdr*)sparse;
int idx = 0, runlen, regval; int idx = 0, runlen, regval;
@ -568,7 +571,7 @@ void hllSparseToDense(robj *o) {
/* If the representation is already the right one return ASAP. */ /* If the representation is already the right one return ASAP. */
hdr = (struct hllhdr*) sparse; hdr = (struct hllhdr*) sparse;
if (hdr->encoding == HLL_DENSE) return; if (hdr->encoding == HLL_DENSE) return REDIS_OK;
/* Create a string of the right size filled with zero bytes. /* Create a string of the right size filled with zero bytes.
* Note that the cached cardinality is set to 0 as a side effect * Note that the cached cardinality is set to 0 as a side effect
@ -601,9 +604,17 @@ void hllSparseToDense(robj *o) {
} }
} }
/* If the sparse representation was valid, we expect to find idx
* set to HLL_REGISTERS. */
if (idx != HLL_REGISTERS) {
sdsfree(dense);
return REDIS_ERR;
}
/* Free the old representation and set the new one. */ /* Free the old representation and set the new one. */
sdsfree(o->ptr); sdsfree(o->ptr);
o->ptr = dense; o->ptr = dense;
return REDIS_OK;
} }
/* "Add" the element in the sparse hyperloglog data structure. /* "Add" the element in the sparse hyperloglog data structure.
@ -809,7 +820,7 @@ updated:
return 1; return 1;
promote: /* Promote to dense representation. */ promote: /* Promote to dense representation. */
hllSparseToDense(o); if (hllSparseToDense(o) == REDIS_ERR) return -1; /* Corrupted HLL. */
hdr = o->ptr; hdr = o->ptr;
return hllDenseAdd(hdr->registers, ele, elesize); return hllDenseAdd(hdr->registers, ele, elesize);
} }
@ -1236,7 +1247,11 @@ void pfdebugCommand(redisClient *c) {
if (c->argc != 3) goto arityerr; if (c->argc != 3) goto arityerr;
addReplyMultiBulkLen(c,HLL_REGISTERS); addReplyMultiBulkLen(c,HLL_REGISTERS);
hllSparseToDense(o); if (hllSparseToDense(o) == REDIS_ERR) {
addReplyError(c,"HLL sparse encoding is corrupted");
return;
}
hdr = o->ptr;
for (j = 0; j < HLL_REGISTERS; j++) { for (j = 0; j < HLL_REGISTERS; j++) {
uint8_t val; uint8_t val;