1214aa841bc (reftable: add blocksource, an abstraction for random
access reads, 2021-10-07), makes the assumption that it is ok to
free a reftable_block pointing to NULL if the size is also set to
0, but implements that using a memset call that at least in glibc
based system will trigger a runtime exception if called with a
NULL pointer as its first parameter.
Avoid doing so by adding a conditional to check for the size in all
three identically looking functions that were affected, and therefore,
still allow memset to help catch callers that might incorrectly pass
a NULL pointer with a non zero size, but avoiding the exception for
the valid cases.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@xxxxxxxxx>
---
Changes since v1:
- Improved logic as suggested by Junio
- Hopefully also improved commit message
reftable/blocksource.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/reftable/blocksource.c b/reftable/blocksource.c
index 0044eecd9aa..db1b7dc966f 100644
--- a/reftable/blocksource.c
+++ b/reftable/blocksource.c
@@ -15,7 +15,8 @@ license that can be found in the LICENSE file or at
static void strbuf_return_block(void *b, struct reftable_block *dest)
{
- memset(dest->data, 0xff, dest->len);
+ if (dest->len)
+ memset(dest->data, 0xff, dest->len);
reftable_free(dest->data);
}
@@ -56,7 +57,8 @@ void block_source_from_strbuf(struct reftable_block_source *bs,
static void malloc_return_block(void *b, struct reftable_block *dest)
{
- memset(dest->data, 0xff, dest->len);
+ if (dest->len)
+ memset(dest->data, 0xff, dest->len);
reftable_free(dest->data);
}
@@ -85,7 +87,8 @@ static uint64_t file_size(void *b)
static void file_return_block(void *b, struct reftable_block *dest)
{
- memset(dest->data, 0xff, dest->len);
+ if (dest->len)
+ memset(dest->data, 0xff, dest->len);
reftable_free(dest->data);
}
--
2.36.0.rc2.283.gbef64175c85
