[PATCH v3 29/32] submodule--helper: check repo{_submodule,}_init() return values
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Aug 21, 2022, 13:57 UTC
- Message-ID
- <patch-v3-29.32-d4b55f07a30-20220821T130231Z-avarab@gmail.com>
- In-Reply-To
- <cover-v3-00.32-00000000000-20220821T130231Z-avarab@gmail.com>
Fix code added in ce125d431aa (submodule: extract path to submodule gitdir func, 2021-09-15) and a77c3fcb5ec (submodule--helper: get remote names from any repository, 2022-03-04) which failed to check the return values of repo_init() and repo_submodule_init(). If we failed to initialize the repository or submodule we could segfault when trying to access the invalid repository structs.
Let's also check that these were the only such logic errors in the codebase by making use of the "warn_unused_result" attribute. This is valid as of GCC 3.4.0 (and clang will catch it via its faking of __GNUC__ ).
As the comment being added to git-compat-util.h we're piggy-backing on the LAST_ARG_MUST_BE_NULL version check out of lazyness. See 9fe3edc47f1 (Add the LAST_ARG_MUST_BE_NULL macro, 2013-07-18) for its addition. The marginal benefit of covering gcc 3.4.0..4.0.0 is near-zero (or zero) at this point. It mostly matters that we catch this somewhere.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> --- builtin/submodule--helper.c | 9 +++++++-- git-compat-util.h | 3 +++ repository.h | 3 +++ 3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c index 5f109d422ea..88fc01320f3 100644 --- a/builtin/submodule--helper.c +++ b/builtin/submodule--helper.c @@ -63,7 +63,10 @@ static char *get_default_remote_submodule(const char *module_path) { struct repository subrepo; - repo_submodule_init(&subrepo, the_repository, module_path, null_oid()); + if (repo_submodule_init(&subrepo, the_repository, module_path, + null_oid()) < 0) + die(_("could not get a repository handle for submodule '%s'"), + module_path); return repo_get_default_remote(&subrepo); } @@ -1483,7 +1486,9 @@ static int add_possible_reference_from_superproject( struct strbuf err = STRBUF_INIT; strbuf_add(&sb, odb->path, len); - repo_init(&alternate, sb.buf, NULL); + if (repo_init(&alternate, sb.buf, NULL) < 0) + die(_("could not get a repository handle for gitdir '%s'"), + sb.buf); /* * We need to end the new path with '/' to mark it as a dir, diff --git a/git-compat-util.h b/git-compat-util.h index 36a25ae252f..01d88650ba3 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -568,8 +568,11 @@ static inline int git_has_dir_sep(const char *path) /* The sentinel attribute is valid from gcc version 4.0 */ #if defined(__GNUC__) && (__GNUC__ >= 4) #define LAST_ARG_MUST_BE_NULL __attribute__((sentinel)) +/* warn_unused_result exists as of gcc 3.4.0, but be lazy and check 4.0 */ +#define RESULT_MUST_BE_USED __attribute__ ((warn_unused_result)) #else #define LAST_ARG_MUST_BE_NULL +#define RESULT_MUST_BE_USED #endif #define MAYBE_UNUSED __attribute__((__unused__)) diff --git a/repository.h b/repository.h index 797f471cce9..24316ac944e 100644 --- a/repository.h +++ b/repository.h @@ -1,6 +1,7 @@ #ifndef REPOSITORY_H #define REPOSITORY_H +#include "git-compat-util.h" #include "path.h" struct config_set; @@ -186,6 +187,7 @@ void repo_set_gitdir(struct repository *repo, const char *root, void repo_set_worktree(struct repository *repo, const char *path); void repo_set_hash_algo(struct repository *repo, int algo); void initialize_the_repository(void); +RESULT_MUST_BE_USED int repo_init(struct repository *r, const char *gitdir, const char *worktree); /* @@ -197,6 +199,7 @@ int repo_init(struct repository *r, const char *gitdir, const char *worktree); * Return 0 upon success and a non-zero value upon failure. */ struct object_id; +RESULT_MUST_BE_USED int repo_submodule_init(struct repository *subrepo, struct repository *superproject, const char *path,
-- 2.37.2.1279.g64dec4e13cf