Thread (61 messages) flat view 61 messages, 6 authors, 2021-09-27

Re: [PATCH 5/7] grep: allocate subrepos on heap

From: Emily Shaffer <hidden>
Date: 2021-08-11 21:50:51

On Tue, Aug 10, 2021 at 11:28:43AM -0700, Jonathan Tan wrote:
quoted hunk ↗ jump to hunk
diff --git a/builtin/grep.c b/builtin/grep.c
index 9e61c7c993..5a40e18e47 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -65,6 +65,9 @@ static int todo_done;
 /* Has all work items been added? */
 static int all_work_added;
 
+static struct repository **repos_to_free;
+static size_t repos_to_free_nr, repos_to_free_alloc;
One thing I was curious about was whether it would make more sense to
use an existing utility library in Git to handle this. But I think we
kind of are, since ALLOC_GROW is used, so this is idiomatic for Git
project. Ok, fine, I guess this is life at C ;)
quoted hunk ↗ jump to hunk
+
 /* This lock protects all the variables above. */
 static pthread_mutex_t grep_mutex;
 
@@ -168,6 +171,17 @@ static void work_done(struct work_item *w)
 	grep_unlock();
 }
 
+static void free_repos(void)
+{
+	int i;
+
+	for (i = 0; i < repos_to_free_nr; i++) {
+		repo_clear(repos_to_free[i]);
+		free(repos_to_free[i]);
+	}
+	free(repos_to_free);
+}
Should repos_to_free_nr be reset here? I guess it doesn't make sense to,
since we'd be trying to use-after-free the initial repos_to_free head
pointer too if we wanted to reuse this array.
quoted hunk ↗ jump to hunk
+
 static void *run(void *arg)
 {
 	int hit = 0;
@@ -415,19 +429,24 @@ static int grep_submodule(struct grep_opt *opt,
 			  const struct object_id *oid,
 			  const char *filename, const char *path, int cached)
 {
-	struct repository subrepo;
+	struct repository *subrepo;
 	struct repository *superproject = opt->repo;
 	const struct submodule *sub;
 	struct grep_opt subopt;
-	int hit;
+	int hit = 0;
 
 	sub = submodule_from_path(superproject, null_oid(), path);
 
 	if (!is_submodule_active(superproject, path))
 		return 0;
 
-	if (repo_submodule_init(&subrepo, superproject, sub))
+	subrepo = xmalloc(sizeof(*subrepo));
+	if (repo_submodule_init(subrepo, superproject, sub)) {
+		free(subrepo);
 		return 0;
+	}
+	ALLOC_GROW(repos_to_free, repos_to_free_nr + 1, repos_to_free_alloc);
+	repos_to_free[repos_to_free_nr++] = subrepo;
Is this the only place we add to the repos_to_free array? It looks like
yes, so I guess this doesn't need a helper.
quoted hunk ↗ jump to hunk
 
 	/*
 	 * NEEDSWORK: repo_read_gitmodules() might call
@@ -438,7 +457,7 @@ static int grep_submodule(struct grep_opt *opt,
 	 * subrepo's odbs to the in-memory alternates list.
 	 */
 	obj_read_lock();
-	repo_read_gitmodules(&subrepo, 0);
+	repo_read_gitmodules(subrepo, 0);
 
 	/*
 	 * NEEDSWORK: This adds the submodule's object directory to the list of
@@ -450,11 +469,11 @@ static int grep_submodule(struct grep_opt *opt,
 	 * store is no longer global and instead is a member of the repository
 	 * object.
 	 */
-	add_submodule_odb_by_path(subrepo.objects->odb->path);
+	add_submodule_odb_by_path(subrepo->objects->odb->path);
 	obj_read_unlock();
 
 	memcpy(&subopt, opt, sizeof(subopt));
-	subopt.repo = &subrepo;
+	subopt.repo = subrepo;
 
 	if (oid) {
 		enum object_type object_type;
@@ -464,9 +483,9 @@ static int grep_submodule(struct grep_opt *opt,
 		struct strbuf base = STRBUF_INIT;
 
 		obj_read_lock();
-		object_type = oid_object_info(&subrepo, oid, NULL);
+		object_type = oid_object_info(subrepo, oid, NULL);
 		obj_read_unlock();
-		data = read_object_with_reference(&subrepo,
+		data = read_object_with_reference(subrepo,
 						  oid, tree_type,
 						  &size, NULL);
 		if (!data)
@@ -484,7 +503,6 @@ static int grep_submodule(struct grep_opt *opt,
 		hit = grep_cache(&subopt, pathspec, cached);
 	}
 
-	repo_clear(&subrepo);
 	return hit;
 }
 
@@ -1182,5 +1200,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		run_pager(&opt, prefix);
 	clear_pathspec(&pathspec);
 	free_grep_patterns(&opt);
+	free_repos();
 	return !hit;
 }
The rest of the diff seems to be a pretty clear object-becomes-reference
conversion, so...

Reviewed-by: Emily Shaffer <redacted>
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help