On Tue, Aug 08, 2023 at 03:22:41PM -0400, Jeff King wrote:
> Subject: [PATCH] commit-graph: fix small leak with invalid changedPathsVersion
>
> When writing a commit graph, we sanity-check the value of
> commitgraph.changedPathsVersion and return early if it's invalid. But we
> only do so after allocating the write_commit_graph_context, meaing we
> leak it. We could "goto cleanup" to fix this, but instead let's push
> this check to the top of the function with the other early checks which
> return before doing any work.
I am tempted to do this on top, but maybe it is just churn. I dunno.
-- >8 --
Subject: [PATCH] commit-graph: store write context on stack rather than heap
In write_commit_graph(), we allocate our context struct on the heap.
But there's no reason to do so, since it's small and we always free it
when exiting the function. Converting it to a stack variable is slightly
more efficient, but also can prevent some leaks (such as the one fixed
in the previous commit, though to be fair this only helps for such a
limited leak; once any sub-fields of the struct require allocation, it
has to be cleaned up).
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
commit-graph.c | 140 ++++++++++++++++++++++++-------------------------
1 file changed, 69 insertions(+), 71 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c
index ccc21c6708..b8db056f37 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -2358,7 +2358,7 @@ int write_commit_graph(struct object_directory *odb,
const struct commit_graph_opts *opts)
{
struct repository *r = the_repository;
- struct write_commit_graph_context *ctx;
+ struct write_commit_graph_context ctx;
uint32_t i;
int res = 0;
int replace = 0;
@@ -2379,16 +2379,16 @@ int write_commit_graph(struct object_directory *odb,
return 0;
}
- CALLOC_ARRAY(ctx, 1);
- ctx->r = r;
- ctx->odb = odb;
- ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
- ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
- ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
- ctx->opts = opts;
- ctx->total_bloom_filter_data_size = 0;
- ctx->write_generation_data = (get_configured_generation_version(r) == 2);
- ctx->num_generation_data_overflows = 0;
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.r = r;
+ ctx.odb = odb;
+ ctx.append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
+ ctx.report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
+ ctx.split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
+ ctx.opts = opts;
+ ctx.total_bloom_filter_data_size = 0;
+ ctx.write_generation_data = (get_configured_generation_version(r) == 2);
+ ctx.num_generation_data_overflows = 0;
bloom_settings.hash_version = r->settings.commit_graph_changed_paths_version == 2
? 2 : 1;
@@ -2398,14 +2398,14 @@ int write_commit_graph(struct object_directory *odb,
bloom_settings.num_hashes);
bloom_settings.max_changed_paths = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS",
bloom_settings.max_changed_paths);
- ctx->bloom_settings = &bloom_settings;
+ ctx.bloom_settings = &bloom_settings;
init_topo_level_slab(&topo_levels);
- ctx->topo_levels = &topo_levels;
+ ctx.topo_levels = &topo_levels;
- prepare_commit_graph(ctx->r);
- if (ctx->r->objects->commit_graph) {
- struct commit_graph *g = ctx->r->objects->commit_graph;
+ prepare_commit_graph(ctx.r);
+ if (ctx.r->objects->commit_graph) {
+ struct commit_graph *g = ctx.r->objects->commit_graph;
while (g) {
g->topo_levels = &topo_levels;
@@ -2414,128 +2414,126 @@ int write_commit_graph(struct object_directory *odb,
}
if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)
- ctx->changed_paths = 1;
+ ctx.changed_paths = 1;
if (!(flags & COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS)) {
struct commit_graph *g;
- g = ctx->r->objects->commit_graph;
+ g = ctx.r->objects->commit_graph;
/* We have changed-paths already. Keep them in the next graph */
if (g && g->bloom_filter_settings) {
- ctx->changed_paths = 1;
- ctx->bloom_settings = g->bloom_filter_settings;
+ ctx.changed_paths = 1;
+ ctx.bloom_settings = g->bloom_filter_settings;
}
}
- if (ctx->split) {
- struct commit_graph *g = ctx->r->objects->commit_graph;
+ if (ctx.split) {
+ struct commit_graph *g = ctx.r->objects->commit_graph;
while (g) {
- ctx->num_commit_graphs_before++;
+ ctx.num_commit_graphs_before++;
g = g->base_graph;
}
- if (ctx->num_commit_graphs_before) {
- ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
- i = ctx->num_commit_graphs_before;
- g = ctx->r->objects->commit_graph;
+ if (ctx.num_commit_graphs_before) {
+ ALLOC_ARRAY(ctx.commit_graph_filenames_before, ctx.num_commit_graphs_before);
+ i = ctx.num_commit_graphs_before;
+ g = ctx.r->objects->commit_graph;
while (g) {
- ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
+ ctx.commit_graph_filenames_before[--i] = xstrdup(g->filename);
g = g->base_graph;
}
}
- if (ctx->opts)
- replace = ctx->opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
+ if (ctx.opts)
+ replace = ctx.opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
}
- ctx->approx_nr_objects = repo_approximate_object_count(the_repository);
+ ctx.approx_nr_objects = repo_approximate_object_count(the_repository);
- if (ctx->append && ctx->r->objects->commit_graph) {
- struct commit_graph *g = ctx->r->objects->commit_graph;
+ if (ctx.append && ctx.r->objects->commit_graph) {
+ struct commit_graph *g = ctx.r->objects->commit_graph;
for (i = 0; i < g->num_commits; i++) {
struct object_id oid;
oidread(&oid, g->chunk_oid_lookup + g->hash_len * i);
- oid_array_append(&ctx->oids, &oid);
+ oid_array_append(&ctx.oids, &oid);
}
}
if (pack_indexes) {
- ctx->order_by_pack = 1;
- if ((res = fill_oids_from_packs(ctx, pack_indexes)))
+ ctx.order_by_pack = 1;
+ if ((res = fill_oids_from_packs(&ctx, pack_indexes)))
goto cleanup;
}
if (commits) {
- if ((res = fill_oids_from_commits(ctx, commits)))
+ if ((res = fill_oids_from_commits(&ctx, commits)))
goto cleanup;
}
if (!pack_indexes && !commits) {
- ctx->order_by_pack = 1;
- fill_oids_from_all_packs(ctx);
+ ctx.order_by_pack = 1;
+ fill_oids_from_all_packs(&ctx);
}
- close_reachable(ctx);
+ close_reachable(&ctx);
- copy_oids_to_commits(ctx);
+ copy_oids_to_commits(&ctx);
- if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
+ if (ctx.commits.nr >= GRAPH_EDGE_LAST_MASK) {
error(_("too many commits to write graph"));
res = -1;
goto cleanup;
}
- if (!ctx->commits.nr && !replace)
+ if (!ctx.commits.nr && !replace)
goto cleanup;
- if (ctx->split) {
- split_graph_merge_strategy(ctx);
+ if (ctx.split) {
+ split_graph_merge_strategy(&ctx);
if (!replace)
- merge_commit_graphs(ctx);
+ merge_commit_graphs(&ctx);
} else
- ctx->num_commit_graphs_after = 1;
+ ctx.num_commit_graphs_after = 1;
- ctx->trust_generation_numbers = validate_mixed_generation_chain(ctx->r->objects->commit_graph);
+ ctx.trust_generation_numbers = validate_mixed_generation_chain(ctx.r->objects->commit_graph);
- compute_topological_levels(ctx);
- if (ctx->write_generation_data)
- compute_generation_numbers(ctx);
+ compute_topological_levels(&ctx);
+ if (ctx.write_generation_data)
+ compute_generation_numbers(&ctx);
- if (ctx->changed_paths)
- compute_bloom_filters(ctx);
+ if (ctx.changed_paths)
+ compute_bloom_filters(&ctx);
- res = write_commit_graph_file(ctx);
+ res = write_commit_graph_file(&ctx);
- if (ctx->split)
- mark_commit_graphs(ctx);
+ if (ctx.split)
+ mark_commit_graphs(&ctx);
- expire_commit_graphs(ctx);
+ expire_commit_graphs(&ctx);
cleanup:
- free(ctx->graph_name);
- free(ctx->commits.list);
- oid_array_clear(&ctx->oids);
+ free(ctx.graph_name);
+ free(ctx.commits.list);
+ oid_array_clear(&ctx.oids);
clear_topo_level_slab(&topo_levels);
- if (ctx->commit_graph_filenames_after) {
- for (i = 0; i < ctx->num_commit_graphs_after; i++) {
- free(ctx->commit_graph_filenames_after[i]);
- free(ctx->commit_graph_hash_after[i]);
+ if (ctx.commit_graph_filenames_after) {
+ for (i = 0; i < ctx.num_commit_graphs_after; i++) {
+ free(ctx.commit_graph_filenames_after[i]);
+ free(ctx.commit_graph_hash_after[i]);
}
- for (i = 0; i < ctx->num_commit_graphs_before; i++)
- free(ctx->commit_graph_filenames_before[i]);
+ for (i = 0; i < ctx.num_commit_graphs_before; i++)
+ free(ctx.commit_graph_filenames_before[i]);
- free(ctx->commit_graph_filenames_after);
- free(ctx->commit_graph_filenames_before);
- free(ctx->commit_graph_hash_after);
+ free(ctx.commit_graph_filenames_after);
+ free(ctx.commit_graph_filenames_before);
+ free(ctx.commit_graph_hash_after);
}
- free(ctx);
-
return res;
}
--
2.42.0.rc0.376.g66bfc4f195
