lockfile API users: simplify and don't leak "path"

avar · gitster · commit ef3fe214484f · 2022-03-04T13:24:19.000-08:00
Fix a memory leak in code added in 6c622f9 (commit-graph: write commit-graph chains, 2019-06-18). We needed to free the "lock_name" if we encounter errors, and the "graph_name" after we'd run unlink() on it. For the case of write_commit_graph_file() refactoring the code to free the "lock_name" after we were done using the "struct lock_file lk" would have made the control flow more complex. Luckily we can free the "lock_file" right after the hold_lock_file_for_update() call, if it makes use of "path" at all it'll have copied its contents to a "struct strbuf" of its own. While I'm at it let's fix code added in fb10ca5 (sparse-checkout: write using lockfile, 2019-11-21) in write_patterns_and_update() to avoid the same complexity that I thought I needed when I wrote the initial fix for write_commit_graph_file(). We can free the "sparse_filename" right after calling hold_lock_file_for_update(), we don't need to wait until we're exiting the function to do so. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
@@ -328,11 +328,11 @@ static int write_patterns_and_update(struct pattern_list *pl)
 
 	fd = hold_lock_file_for_update(&lk, sparse_filename,
 				      LOCK_DIE_ON_ERROR);
+	free(sparse_filename);
 
 	result = update_working_directory(pl);
 	if (result) {
 		rollback_lock_file(&lk);
-		free(sparse_filename);
 		clear_pattern_list(pl);
 		update_working_directory(NULL);
 		return result;
@@ -348,7 +348,6 @@ static int write_patterns_and_update(struct pattern_list *pl)
 	fflush(fp);
 	commit_lock_file(&lk);
 
-	free(sparse_filename);
 	clear_pattern_list(pl);
 
 	return 0;
diff --git a/commit-graph.c b/commit-graph.c
@@ -1854,6 +1854,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
 		hold_lock_file_for_update_mode(&lk, lock_name,
 					       LOCK_DIE_ON_ERROR, 0444);
+		free(lock_name);
 
 		fd = git_mkstemp_mode(ctx->graph_name, 0444);
 		if (fd < 0) {
@@ -1978,6 +1979,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 		} else {
 			char *graph_name = get_commit_graph_filename(ctx->odb);
 			unlink(graph_name);
+			free(graph_name);
 		}
 
 		ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(hash_to_hex(file_hash));
