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authorChris Luke <chrisy@flirble.org>2016-07-30 15:05:07 -0400
committerDave Barach <openvpp@barachs.net>2016-08-31 12:57:33 +0000
commit5cdaf6358266eb883a2e48239a83e9f56c3c5bad (patch)
tree6583d27668c10948640d225df4a64b43d341f325
parent54ccf2261cb1f4afd966b7b1e92689183cb17836 (diff)
VPP-189 Tweak hash_foreach_pair to avoid static warning
Coverity doesn't like when an incrementing pointer is taken from the address of a singleton; it cries that this is a potential buffer overrun. Since the cases of this in hash_foreach_pair are based on items from a simple union used just to have different types point to the same location it's a simple matter of using the pointer to that location directly. Since we then aren't using the members of the union, we can change that to an opaque pointer (void *). This accounts for >60 issues in Coverity. Whilst here, convert some useful existing comments into a docblock. Change-Id: I114183ab7d7948d4a6a703451417f79fa37634eb Signed-off-by: Chris Luke <chrisy@flirble.org>
-rw-r--r--vppinfra/vppinfra/hash.h31
1 files changed, 21 insertions, 10 deletions
diff --git a/vppinfra/vppinfra/hash.h b/vppinfra/vppinfra/hash.h
index f796f2dca09..4db5a57602e 100644
--- a/vppinfra/vppinfra/hash.h
+++ b/vppinfra/vppinfra/hash.h
@@ -329,21 +329,32 @@ hash_forward (hash_t * h, void *v, uword n)
return (u8 *) v + ((n * sizeof (hash_pair_t)) << h->log2_pair_size);
}
-/* Iterate over hash pairs
- @param p the current (key,value) pair
- @param v the hash table to iterate
- @param body the operation to perform on each (key,value) pair.
- executes body with each active hash pair
+/** Iterate over hash pairs.
+
+ @param p The current (key,value) pair. This should be of type
+ <code>(hash_pair_t *)</code>.
+ @param v The hash table to iterate.
+ @param body The operation to perform on each (key,value) pair.
+
+ Executes the expression or code block @c body with each active hash pair.
*/
+/* A previous version of this macro made use of the hash_pair_union_t
+ * structure; this version does not since that approach mightily upset
+ * the static analysis tool. In the rare chance someone is reading this
+ * code, pretend that _p below is of type hash_pair_union_t and that when
+ * used as an rvalue it's really using one of the union members as the
+ * rvalue. If you were confused before you might be marginally less
+ * confused after.
+ */
#define hash_foreach_pair(p,v,body) \
do { \
__label__ _hash_foreach_done; \
hash_t * _h = hash_header (v); \
- hash_pair_union_t * _p; \
+ void * _p; \
hash_pair_t * _q, * _q_end; \
uword _i, _i1, _id, _pair_increment; \
\
- _p = (hash_pair_union_t *) (v); \
+ _p = (v); \
_i = 0; \
_pair_increment = 1; \
if ((v)) \
@@ -356,12 +367,12 @@ do { \
do { \
if (_id & 1) \
{ \
- _q = &_p->direct; \
+ _q = _p; \
_q_end = _q + _pair_increment; \
} \
else \
{ \
- hash_pair_indirect_t * _pi = &_p->indirect; \
+ hash_pair_indirect_t * _pi = _p; \
_q = _pi->pairs; \
if (_h->log2_pair_size > 0) \
_q_end = hash_forward (_h, _q, indirect_pair_get_len (_pi)); \
@@ -384,7 +395,7 @@ do { \
_q += _pair_increment; \
} \
\
- _p = (hash_pair_union_t *) (&_p->direct + _pair_increment); \
+ _p = (hash_pair_t *)_p + _pair_increment; \
_id = _id / 2; \
_i++; \
} while (_i < _i1); \