Merge branch 'rs/oidtree-alignment-fix'
Codepath to access recently added oidtree data structure had
to make unaligned accesses to oids, which has been corrected.
* rs/oidtree-alignment-fix:
oidtree: avoid unaligned access to crit-bit tree
diff --git a/cbtree.h b/cbtree.h
index fe45870..a04a312 100644
--- a/cbtree.h
+++ b/cbtree.h
@@ -25,7 +25,7 @@
*/
uint32_t byte;
uint8_t otherbits;
- uint8_t k[FLEX_ARRAY]; /* arbitrary data */
+ uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
};
struct cb_tree {
diff --git a/hash.h b/hash.h
index 27a1802..9e25c40 100644
--- a/hash.h
+++ b/hash.h
@@ -115,7 +115,7 @@
struct object_id {
unsigned char hash[GIT_MAX_RAWSZ];
- int algo;
+ int algo; /* XXX requires 4-byte alignment */
};
/* A suitably aligned type for stack allocations of hash contexts. */
diff --git a/oidtree.c b/oidtree.c
index 580cab8..0d39389 100644
--- a/oidtree.c
+++ b/oidtree.c
@@ -31,12 +31,19 @@
void oidtree_insert(struct oidtree *ot, const struct object_id *oid)
{
struct cb_node *on;
+ struct object_id k;
if (!oid->algo)
BUG("oidtree_insert requires oid->algo");
on = mem_pool_alloc(&ot->mem_pool, sizeof(*on) + sizeof(*oid));
- oidcpy_with_padding((struct object_id *)on->k, oid);
+
+ /*
+ * Clear the padding and copy the result in separate steps to
+ * respect the 4-byte alignment needed by struct object_id.
+ */
+ oidcpy_with_padding(&k, oid);
+ memcpy(on->k, &k, sizeof(k));
/*
* n.b. Current callers won't get us duplicates, here. If a
@@ -68,17 +75,20 @@
static enum cb_next iter(struct cb_node *n, void *arg)
{
struct oidtree_iter_data *x = arg;
- const struct object_id *oid = (const struct object_id *)n->k;
+ struct object_id k;
- if (x->algo != GIT_HASH_UNKNOWN && x->algo != oid->algo)
+ /* Copy to provide 4-byte alignment needed by struct object_id. */
+ memcpy(&k, n->k, sizeof(k));
+
+ if (x->algo != GIT_HASH_UNKNOWN && x->algo != k.algo)
return CB_CONTINUE;
if (x->last_nibble_at) {
- if ((oid->hash[*x->last_nibble_at] ^ x->last_byte) & 0xf0)
+ if ((k.hash[*x->last_nibble_at] ^ x->last_byte) & 0xf0)
return CB_CONTINUE;
}
- return x->fn(oid, x->arg);
+ return x->fn(&k, x->arg);
}
void oidtree_each(struct oidtree *ot, const struct object_id *oid,
