git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH] checkout: fix "branch info" memory leaks

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
Oct 14, 2021, 00:10 UTC
Message-ID
<patch-1.1-9b17170b794-20211014T000949Z-avarab@gmail.com>

The "checkout" command is one of the main sources of leaks in the test suite, let's fix the common ones by not leaking from the "struct branch_info".

Doing this is rather straightforward, albeit verbose, we need to xstrdup() constant strings going into the struct, and free() the ones we clobber as we go along.

This also means that we can delete previous partial leak fixes in this area, i.e. the "path_to_free" accounting added by 96ec7b1e708 (Convert resolve_ref+xstrdup to new resolve_refdup function, 2011-12-13).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---

As with other leak fixes I merged this to "seen" and tested it in combination with in-flight topics under GIT_TEST_PASSING_SANITIZE_LEAK=true.

 builtin/checkout.c                | 76 +++++++++++++++++++++----------
 t/t1005-read-tree-reset.sh        |  1 +
 t/t1406-submodule-ref-store.sh    |  1 +
 t/t2008-checkout-subdir.sh        |  1 +
 t/t2014-checkout-switch.sh        |  2 +
 t/t2026-checkout-pathspec-file.sh |  1 +
 t/t9102-git-svn-deep-rmdir.sh     |  2 +
 7 files changed, 59 insertions(+), 25 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8c69dcdf72a..a85eb66da16 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -103,6 +103,16 @@ struct branch_info {
 	char *checkout;
 };
 
+static void branch_info_release(struct branch_info *info)
+{
+	if (!info)
+		return;
+	free((char *)info->name);
+	free((char *)info->path);
+	free(info->refname);
+	free(info->checkout);
+}
+
 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
 			      int changed)
 {
@@ -686,8 +696,10 @@ static void setup_branch_path(struct branch_info *branch)
 		repo_get_oid_committish(the_repository, branch->name, &branch->oid);
 
 	strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
-	if (strcmp(buf.buf, branch->name))
+	if (strcmp(buf.buf, branch->name)) {
+		free((char *)branch->name);
 		branch->name = xstrdup(buf.buf);
+	}
 	strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 	branch->path = strbuf_detach(&buf, NULL);
 }
@@ -896,7 +908,9 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 				      opts->new_branch_log,
 				      opts->quiet,
 				      opts->track);
-		new_branch_info->name = opts->new_branch;
+		free((char *)new_branch_info->name);
+		free(new_branch_info->refname);
+		new_branch_info->name = xstrdup(opts->new_branch);
 		setup_branch_path(new_branch_info);
 	}
 
@@ -1064,8 +1078,7 @@ static int switch_branches(const struct checkout_opts *opts,
 			   struct branch_info *new_branch_info)
 {
 	int ret = 0;
-	struct branch_info old_branch_info;
-	void *path_to_free;
+	struct branch_info old_branch_info = { 0 };
 	struct object_id rev;
 	int flag, writeout_error = 0;
 	int do_merge = 1;
@@ -1073,25 +1086,32 @@ static int switch_branches(const struct checkout_opts *opts,
 	trace2_cmd_mode("branch");
 
 	memset(&old_branch_info, 0, sizeof(old_branch_info));
-	old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
+	old_branch_info.path = resolve_refdup("HEAD", 0, &rev, &flag);
 	if (old_branch_info.path)
 		old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
-	if (!(flag & REF_ISSYMREF))
+	if (!(flag & REF_ISSYMREF)) {
+		free((char *)old_branch_info.path);
 		old_branch_info.path = NULL;
+	}
 
-	if (old_branch_info.path)
-		skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
+	if (old_branch_info.path) {
+		const char *p;
+		if (skip_prefix(old_branch_info.path, "refs/heads/", &p))
+			old_branch_info.name = xstrdup(p);
+		else
+			BUG("Should be able to skip with %s!", old_branch_info.path);
+	}
 
 	if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
 		if (new_branch_info->name)
 			BUG("'switch --orphan' should never accept a commit as starting point");
 		new_branch_info->commit = NULL;
-		new_branch_info->name = "(empty)";
+		new_branch_info->name = xstrdup("(empty)");
 		do_merge = 1;
 	}
 
 	if (!new_branch_info->name) {
-		new_branch_info->name = "HEAD";
+		new_branch_info->name = xstrdup("HEAD");
 		new_branch_info->commit = old_branch_info.commit;
 		if (!new_branch_info->commit)
 			die(_("You are on a branch yet to be born"));
@@ -1104,7 +1124,7 @@ static int switch_branches(const struct checkout_opts *opts,
 	if (do_merge) {
 		ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
 		if (ret) {
-			free(path_to_free);
+			branch_info_release(&old_branch_info);
 			return ret;
 		}
 	}
@@ -1115,7 +1135,8 @@ static int switch_branches(const struct checkout_opts *opts,
 	update_refs_for_switch(opts, &old_branch_info, new_branch_info);
 
 	ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
-	free(path_to_free);
+	branch_info_release(&old_branch_info);
+
 	return ret || writeout_error;
 }
 
@@ -1147,7 +1168,7 @@ static void setup_new_branch_info_and_source_tree(
 	struct tree **source_tree = &opts->source_tree;
 	struct object_id branch_rev;
 
-	new_branch_info->name = arg;
+	new_branch_info->name = xstrdup(arg);
 	setup_branch_path(new_branch_info);
 
 	if (!check_refname_format(new_branch_info->path, 0) &&
@@ -1576,12 +1597,11 @@ static char cb_option = 'b';
 
 static int checkout_main(int argc, const char **argv, const char *prefix,
 			 struct checkout_opts *opts, struct option *options,
-			 const char * const usagestr[])
+			 const char * const usagestr[],
+			 struct branch_info *new_branch_info)
 {
-	struct branch_info new_branch_info;
 	int parseopt_flags = 0;
 
-	memset(&new_branch_info, 0, sizeof(new_branch_info));
 	opts->overwrite_ignore = 1;
 	opts->prefix = prefix;
 	opts->show_progress = -1;
@@ -1690,7 +1710,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 			opts->track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts->new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     &new_branch_info, opts, &rev);
+					     new_branch_info, opts, &rev);
 		argv += n;
 		argc -= n;
 	} else if (!opts->accept_ref && opts->from_treeish) {
@@ -1699,7 +1719,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		if (get_oid_mb(opts->from_treeish, &rev))
 			die(_("could not resolve %s"), opts->from_treeish);
 
-		setup_new_branch_info_and_source_tree(&new_branch_info,
+		setup_new_branch_info_and_source_tree(new_branch_info,
 						      opts, &rev,
 						      opts->from_treeish);
 
@@ -1719,7 +1739,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		 * Try to give more helpful suggestion.
 		 * new_branch && argc > 1 will be caught later.
 		 */
-		if (opts->new_branch && argc == 1 && !new_branch_info.commit)
+		if (opts->new_branch && argc == 1 && !new_branch_info->commit)
 			die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
 				argv[0], opts->new_branch);
 
@@ -1768,11 +1788,10 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		strbuf_release(&buf);
 	}
 
-	UNLEAK(opts);
 	if (opts->patch_mode || opts->pathspec.nr)
-		return checkout_paths(opts, &new_branch_info);
+		return checkout_paths(opts, new_branch_info);
 	else
-		return checkout_branch(opts, &new_branch_info);
+		return checkout_branch(opts, new_branch_info);
 }
 
 int cmd_checkout(int argc, const char **argv, const char *prefix)
@@ -1791,6 +1810,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 	int ret;
+	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.dwim_new_local_branch = 1;
@@ -1821,7 +1841,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	options = add_checkout_path_options(&opts, options);
 
 	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, checkout_usage);
+			    options, checkout_usage, &new_branch_info);
+	branch_info_release(&new_branch_info);
+	clear_pathspec(&opts.pathspec);
 	FREE_AND_NULL(options);
 	return ret;
 }
@@ -1842,6 +1864,7 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 	int ret;
+	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.dwim_new_local_branch = 1;
@@ -1861,7 +1884,8 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
 	cb_option = 'c';
 
 	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, switch_branch_usage);
+			    options, switch_branch_usage, &new_branch_info);
+	branch_info_release(&new_branch_info);
 	FREE_AND_NULL(options);
 	return ret;
 }
@@ -1883,6 +1907,7 @@ int cmd_restore(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 	int ret;
+	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.accept_ref = 0;
@@ -1898,7 +1923,8 @@ int cmd_restore(int argc, const char **argv, const char *prefix)
 	options = add_checkout_path_options(&opts, options);
 
 	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, restore_usage);
+			    options, restore_usage, &new_branch_info);
+	branch_info_release(&new_branch_info);
 	FREE_AND_NULL(options);
 	return ret;
 }
diff --git a/t/t1005-read-tree-reset.sh b/t/t1005-read-tree-reset.sh
index 83b09e13106..12e30d77d09 100755
--- a/t/t1005-read-tree-reset.sh
+++ b/t/t1005-read-tree-reset.sh
@@ -2,6 +2,7 @@
 
 test_description='read-tree -u --reset'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 
diff --git a/t/t1406-submodule-ref-store.sh b/t/t1406-submodule-ref-store.sh
index 0a87058971e..3c19edcf30b 100755
--- a/t/t1406-submodule-ref-store.sh
+++ b/t/t1406-submodule-ref-store.sh
@@ -5,6 +5,7 @@ test_description='test submodule ref store api'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 RUN="test-tool ref-store submodule:sub"
diff --git a/t/t2008-checkout-subdir.sh b/t/t2008-checkout-subdir.sh
index eadb9434ae7..8a518a44ea2 100755
--- a/t/t2008-checkout-subdir.sh
+++ b/t/t2008-checkout-subdir.sh
@@ -4,6 +4,7 @@
 
 test_description='git checkout from subdirectories'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t2014-checkout-switch.sh b/t/t2014-checkout-switch.sh
index ccfb1471135..c138bdde4fe 100755
--- a/t/t2014-checkout-switch.sh
+++ b/t/t2014-checkout-switch.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='Peter MacMillan'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t2026-checkout-pathspec-file.sh b/t/t2026-checkout-pathspec-file.sh
index 43d31d79485..9db11f86dd6 100755
--- a/t/t2026-checkout-pathspec-file.sh
+++ b/t/t2026-checkout-pathspec-file.sh
@@ -2,6 +2,7 @@
 
 test_description='checkout --pathspec-from-file'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_tick
diff --git a/t/t9102-git-svn-deep-rmdir.sh b/t/t9102-git-svn-deep-rmdir.sh
index 66cd51102c8..7b2049caa0c 100755
--- a/t/t9102-git-svn-deep-rmdir.sh
+++ b/t/t9102-git-svn-deep-rmdir.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 test_description='git svn rmdir'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 test_expect_success 'initialize repo' '

-- 
2.33.1.1346.g48288c3c089
Next: Phillip Wood
Message 1 of 12 in “checkout: fix "branch info" memory leaks”
  1. checkout: fix "branch info" memory leaksÆvar Arnfjörð Bjarmason, Oct 14, 2021
  2. Phillip WoodOct 14, 2021
  3. To "const char *" and cast on free(), or "char *" and no cast...Ævar Arnfjörð Bjarmason, Oct 14, 2021
  4. Junio C HamanoOct 14, 2021
  5. Phillip WoodOct 15, 2021
  6. Junio C HamanoOct 15, 2021
  7. Eric WongOct 14, 2021
  8. Phillip WoodOct 15, 2021
  9. checkout: fix "branch info" memory leaksÆvar Arnfjörð Bjarmason, Oct 21, 2021
  10. Phillip WoodOct 24, 2021
  11. checkout: fix "branch info" memory leaksÆvar Arnfjörð Bjarmason, Nov 3, 2021
  12. checkout: fix "branch info" memory leaksÆvar Arnfjörð Bjarmason, Nov 16, 2021

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.