Add an option (controlled by an environment variable) perform extra
validations on mem_pool allocated cache entries. When set:
1) Invalidate cache_entry memory when discarding cache_entry.
2) When discarding index_state struct, verify that all cache_entries
were allocated from expected mem_pool.
3) When discarding mem_pools, invalidate mem_pool memory.
This should provide extra checks that mem_pools and their allocated
cache_entries are being used as expected.
Signed-off-by: Jameson Miller <jam...@microsoft.com>
---
cache.h | 7 +++++++
git.c | 3 +++
mem-pool.c | 24 +++++++++++++++++++++++-
mem-pool.h | 2 ++
read-cache.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 82 insertions(+), 1 deletion(-)
diff --git a/cache.h b/cache.h
index 7ed68f28e0..8f10f0649b 100644
--- a/cache.h
+++ b/cache.h
@@ -369,6 +369,13 @@ void discard_index_cache_entry(struct cache_entry *ce);
*/
void discard_transient_cache_entry(struct cache_entry *ce);
+/*
+ * Validate the cache entries in the index. This is an internal
+ * consistency check that the cache_entry structs are allocated from
+ * the expected memory pool.
+ */
+void validate_cache_entries(const struct index_state *istate);
+
#ifndef NO_THE_INDEX_COMPATIBILITY_MACROS
#define active_cache (the_index.cache)
#define active_nr (the_index.cache_nr)
diff --git a/git.c b/git.c
index f598fae7b7..28ec7a6c4f 100644
--- a/git.c
+++ b/git.c
@@ -347,7 +347,10 @@ static int run_builtin(struct cmd_struct *p, int argc,
const char **argv)
trace_argv_printf(argv, "trace: built-in: git");
+ validate_cache_entries(&the_index);
status = p->fn(argc, argv, prefix);
+ validate_cache_entries(&the_index);
+
if (status)
return status;
diff --git a/mem-pool.c b/mem-pool.c
index a495885c4b..77adb5d5b9 100644
--- a/mem-pool.c
+++ b/mem-pool.c
@@ -60,21 +60,43 @@ void mem_pool_discard(struct mem_pool *mem_pool)
{
int i;
struct mp_block *block, *block_to_free;
+ int invalidate_memory = should_validate_cache_entries();
+
for (block = mem_pool->mp_block; block;)
{
block_to_free = block;
block = block->next_block;
+
+ if (invalidate_memory)
+ memset(block_to_free->space, 0xDD, ((char
*)block_to_free->end) - ((char *)block_to_free->space));
+
free(block_to_free);
}
- for (i = 0; i < mem_pool->nr; i++)
+ for (i = 0; i < mem_pool->nr; i++) {
+ memset(mem_pool->custom[i], 0xDD, ((char
*)mem_pool->custom_end[i]) - ((char *)mem_pool->custom[i]));
free(mem_pool->custom[i]);
+ }
free(mem_pool->custom);
free(mem_pool->custom_end);
free(mem_pool);
}
+int should_validate_cache_entries(void)
+{
+ static int validate_index_cache_entries = -1;
+
+ if (validate_index_cache_entries < 0) {
+ if (getenv("GIT_TEST_VALIDATE_INDEX_CACHE_ENTRIES"))
+ validate_index_cache_entries = 1;
+ else
+ validate_index_cache_entries = 0;
+ }
+
+ return validate_index_cache_entries;
+}
+
void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
{
struct mp_block *p;
diff --git a/mem-pool.h b/mem-pool.h
index 34df4fa709..b1f9a920ba 100644
--- a/mem-pool.h
+++ b/mem-pool.h
@@ -63,4 +63,6 @@ void mem_pool_combine(struct mem_pool *dst, struct mem_pool
*src);
*/
int mem_pool_contains(struct mem_pool *mem_pool, void *mem);
+int should_validate_cache_entries(void);
+
#endif
diff --git a/read-cache.c b/read-cache.c
index 01cd7fea41..e1dc9f7f33 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1270,6 +1270,8 @@ int add_index_entry(struct index_state *istate, struct
cache_entry *ce, int opti
{
int pos;
+ validate_cache_entries(istate);
+
if (option & ADD_CACHE_JUST_APPEND)
pos = istate->cache_nr;
else {
@@ -1290,6 +1292,8 @@ int add_index_entry(struct index_state *istate, struct
cache_entry *ce, int opti
istate->cache_nr - pos - 1);
set_index_entry(istate, pos, ce);
istate->cache_changed |= CE_ENTRY_ADDED;
+
+ validate_cache_entries(istate);
return 0;
}
@@ -2013,6 +2017,8 @@ int is_index_unborn(struct index_state *istate)
int discard_index(struct index_state *istate)
{
+ validate_cache_entries(istate);
+
resolve_undo_clear_index(istate);
istate->cache_nr = 0;
istate->cache_changed = 0;
@@ -2035,6 +2041,43 @@ int discard_index(struct index_state *istate)
return 0;
}
+
+/*
+ * Validate the cache entries of this index.
+ * All cache entries associated with this index
+ * should have been allocated by the memory pool
+ * associated with this index, or by a referenced
+ * split index.
+ */
+void validate_cache_entries(const struct index_state *istate)
+{
+ int i;
+ int validate_index_cache_entries = should_validate_cache_entries();
+
+ if (!validate_index_cache_entries)
+ return;
+
+ if (!istate || !istate->initialized)
+ return;
+
+ for (i = 0; i < istate->cache_nr; i++) {
+ if (!istate) {
+ die("internal error: cache entry is not allocated from
expected memory pool");
+ } else if (!istate->ce_mem_pool ||
+ !mem_pool_contains(istate->ce_mem_pool,
istate->cache[i])) {
+ if (!istate->split_index ||
+ !istate->split_index->base ||
+ !istate->split_index->base->ce_mem_pool ||
+
!mem_pool_contains(istate->split_index->base->ce_mem_pool, istate->cache[i])) {
+ die("internal error: cache entry is not
allocated from expected memory pool");
+ }
+ }
+ }
+
+ if (istate->split_index)
+ validate_cache_entries(istate->split_index->base);
+}
+
int unmerged_index(const struct index_state *istate)
{
int i;
@@ -2828,6 +2871,10 @@ void move_index_extensions(struct index_state *dst,
struct index_state *src)
*/
void discard_index_cache_entry(struct cache_entry *ce)
{
+ int invalidate_cache_entry = should_validate_cache_entries();
+
+ if (ce && invalidate_cache_entry)
+ memset(ce, 0xCD, cache_entry_size(ce->ce_namelen));
}
void discard_transient_cache_entry(struct cache_entry *ce)
--
2.14.3
