MINOR: shctx: add a few BUG_ON() for consistency checks

The shctx code relies on sensitive conditions that are hard to infer
from the code itself, let's add some BUG_ON() to verify them. They
helped spot the previous bugs.
This commit is contained in:
Willy Tarreau 2021-11-19 17:47:18 +01:00
parent cafe15c743
commit 48b608026b

View File

@ -34,6 +34,8 @@ struct shared_block *shctx_row_reserve_hot(struct shared_context *shctx,
int freed = 0;
int remain;
BUG_ON(data_len < 0);
/* not enough usable blocks */
if (data_len > shctx->nbav * shctx->block_size)
goto out;
@ -93,6 +95,8 @@ struct shared_block *shctx_row_reserve_hot(struct shared_context *shctx,
block->len = 0;
freed++;
BUG_ON(data_len < 0);
data_len -= shctx->block_size;
if (data_len > 0 || !enough) {
@ -213,6 +217,8 @@ int shctx_row_data_append(struct shared_context *shctx,
/* remaining written bytes in the current block. */
remain = (shctx->block_size * first->block_count - first->len) % shctx->block_size;
BUG_ON(remain < 0);
/* if remain == 0, previous buffers are full, or first->len == 0 */
if (!remain) {
remain = shctx->block_size;
@ -221,6 +227,7 @@ int shctx_row_data_append(struct shared_context *shctx,
else {
/* start must be calculated before remain is modified */
start = shctx->block_size - remain;
BUG_ON(start < 0);
}
/* must not try to copy more than len */
@ -270,8 +277,11 @@ int shctx_row_data_get(struct shared_context *shctx, struct shared_block *first,
if (start == -1)
start = offset - (count - 1) * shctx->block_size;
BUG_ON(start < 0);
/* size can be lower than a block when copying the last block */
size = MIN(shctx->block_size - start, len);
BUG_ON(size < 0);
memcpy(dst, block->data + start, size);
dst += size;