From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Fri, 4 Mar 2022 18:32:14 +0000 (+0100)
Subject: lockfile API users: simplify and don't leak "path"
X-Git-Tag: v2.36.0-rc0~72^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ef3fe214484f79afdad4204d56e0ee7ff6e85a0f;p=thirdparty%2Fgit.git

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

Fix a memory leak in code added in 6c622f9f0bb (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 fb10ca5b543 (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
index 9c338d33ea..270ad49c2b 100644
--- 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
index aab0b29277..b8cde7ea27 100644
--- 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));