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[31.211.229.121]) by smtp.gmail.com with ESMTPSA id k3-v6sm188706lja.8.2019.01.22.13.46.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 13:46:06 -0800 (PST) From: =?utf-8?q?Martin_=C3=85gren?= To: git@vger.kernel.org Cc: Jeff King , "brian m . carlson" Subject: [PATCH v3 2/2] setup: fix memory leaks with `struct repository_format` Date: Tue, 22 Jan 2019 22:45:48 +0100 Message-Id: X-Mailer: git-send-email 2.20.1.98.gecbdaf0899 In-Reply-To: References: MIME-Version: 1.0 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP After we set up a `struct repository_format`, it owns various pieces of allocated memory. We then either use those members, because we decide we want to use the "candidate" repository format, or we discard the candidate / scratch space. In the first case, we transfer ownership of the memory to a few global variables. In the latter case, we just silently drop the struct and end up leaking memory. Introduce an initialization macro `REPOSITORY_FORMAT_INIT` and a function `clear_repository_format()`, to be used on each side of `read_repository_format()`. To have a clear and simple memory ownership, let all users of `struct repository_format` duplicate the strings that they take from it, rather than stealing the pointers. Call `clear_...()` at the start of `read_...()` instead of just zeroing the struct, since we sometimes enter the function multiple times. This means that it is important to initialize the struct before calling `read_...()`, so document that. Teach `read_...()` to clear the struct upon an error, so that it is reset to a safe state, and document this. About that very last point: In `setup_git_directory_gently()`, we look at `repo_fmt.hash_algo` even if `repo_fmt.version` is -1, which we weren't actually supposed to do per the API. After this commit, that's ok. We inherit the existing code's combining "error" and "no version found". Both are signalled through `version == -1` and now both cause us to clear any partial configuration we have picked up. For "extensions.*", that's fine, since they require a positive version number. For "core.bare" and "core.worktree", we're already verifying that we have a non-negative version number before using them. Signed-off-by: Martin Ågren --- cache.h | 27 ++++++++++++++++++++++++--- builtin/init-db.c | 3 ++- repository.c | 3 ++- setup.c | 32 ++++++++++++++++++++------------ worktree.c | 4 +++- 5 files changed, 51 insertions(+), 18 deletions(-) diff --git a/cache.h b/cache.h index ca36b44ee0..ec7c043412 100644 --- a/cache.h +++ b/cache.h @@ -972,14 +972,35 @@ struct repository_format { struct string_list unknown_extensions; }; +/* + * Always use this to initialize a `struct repository_format` + * to a well-defined, default state before calling + * `read_repository()`. + */ +#define REPOSITORY_FORMAT_INIT \ +{ \ + .version = -1, \ + .is_bare = -1, \ + .hash_algo = GIT_HASH_SHA1, \ + .unknown_extensions = STRING_LIST_INIT_DUP, \ +} + /* * Read the repository format characteristics from the config file "path" into - * "format" struct. Returns the numeric version. On error, -1 is returned, - * format->version is set to -1, and all other fields in the struct are - * undefined. + * "format" struct. Returns the numeric version. On error, or if no version is + * found in the configuration, -1 is returned, format->version is set to -1, + * and all other fields in the struct are set to the default configuration + * (REPOSITORY_FORMAT_INIT). Always initialize the struct using + * REPOSITORY_FORMAT_INIT before calling this function. */ int read_repository_format(struct repository_format *format, const char *path); +/* + * Free the memory held onto by `format`, but not the struct itself. + * (No need to use this after `read_repository_format()` fails.) + */ +void clear_repository_format(struct repository_format *format); + /* * Verify that the repository described by repository_format is something we * can read. If it is, return 0. Otherwise, return -1, and "err" will describe diff --git a/builtin/init-db.c b/builtin/init-db.c index 41faffd28d..04c60eaad5 100644 --- a/builtin/init-db.c +++ b/builtin/init-db.c @@ -96,7 +96,7 @@ static void copy_templates(const char *template_dir) struct strbuf path = STRBUF_INIT; struct strbuf template_path = STRBUF_INIT; size_t template_len; - struct repository_format template_format; + struct repository_format template_format = REPOSITORY_FORMAT_INIT; struct strbuf err = STRBUF_INIT; DIR *dir; char *to_free = NULL; @@ -148,6 +148,7 @@ static void copy_templates(const char *template_dir) free(to_free); strbuf_release(&path); strbuf_release(&template_path); + clear_repository_format(&template_format); } static int git_init_db_config(const char *k, const char *v, void *cb) diff --git a/repository.c b/repository.c index 7b02e1dffa..df88705574 100644 --- a/repository.c +++ b/repository.c @@ -148,7 +148,7 @@ int repo_init(struct repository *repo, const char *gitdir, const char *worktree) { - struct repository_format format; + struct repository_format format = REPOSITORY_FORMAT_INIT; memset(repo, 0, sizeof(*repo)); repo->objects = raw_object_store_new(); @@ -165,6 +165,7 @@ int repo_init(struct repository *repo, if (worktree) repo_set_worktree(repo, worktree); + clear_repository_format(&format); return 0; error: diff --git a/setup.c b/setup.c index bb633942bb..14c2f8ce24 100644 --- a/setup.c +++ b/setup.c @@ -477,7 +477,7 @@ static int check_repository_format_gently(const char *gitdir, struct repository_ } repository_format_precious_objects = candidate->precious_objects; - repository_format_partial_clone = candidate->partial_clone; + repository_format_partial_clone = xstrdup_or_null(candidate->partial_clone); repository_format_worktree_config = candidate->worktree_config; string_list_clear(&candidate->unknown_extensions, 0); @@ -500,11 +500,9 @@ static int check_repository_format_gently(const char *gitdir, struct repository_ } if (candidate->work_tree) { free(git_work_tree_cfg); - git_work_tree_cfg = candidate->work_tree; + git_work_tree_cfg = xstrdup(candidate->work_tree); inside_work_tree = -1; } - } else { - free(candidate->work_tree); } return 0; @@ -512,15 +510,21 @@ static int check_repository_format_gently(const char *gitdir, struct repository_ int read_repository_format(struct repository_format *format, const char *path) { - memset(format, 0, sizeof(*format)); - format->version = -1; - format->is_bare = -1; - format->hash_algo = GIT_HASH_SHA1; - string_list_init(&format->unknown_extensions, 1); + clear_repository_format(format); git_config_from_file(check_repo_format, path, format); + if (format->version == -1) + clear_repository_format(format); return format->version; } +void clear_repository_format(struct repository_format *format) +{ + string_list_clear(&format->unknown_extensions, 0); + free(format->work_tree); + free(format->partial_clone); + *format = (struct repository_format)REPOSITORY_FORMAT_INIT; +} + int verify_repository_format(const struct repository_format *format, struct strbuf *err) { @@ -1008,7 +1012,7 @@ int discover_git_directory(struct strbuf *commondir, struct strbuf dir = STRBUF_INIT, err = STRBUF_INIT; size_t gitdir_offset = gitdir->len, cwd_len; size_t commondir_offset = commondir->len; - struct repository_format candidate; + struct repository_format candidate = REPOSITORY_FORMAT_INIT; if (strbuf_getcwd(&dir)) return -1; @@ -1045,9 +1049,11 @@ int discover_git_directory(struct strbuf *commondir, strbuf_release(&err); strbuf_setlen(commondir, commondir_offset); strbuf_setlen(gitdir, gitdir_offset); + clear_repository_format(&candidate); return -1; } + clear_repository_format(&candidate); return 0; } @@ -1056,7 +1062,7 @@ const char *setup_git_directory_gently(int *nongit_ok) static struct strbuf cwd = STRBUF_INIT; struct strbuf dir = STRBUF_INIT, gitdir = STRBUF_INIT; const char *prefix; - struct repository_format repo_fmt; + struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT; /* * We may have read an incomplete configuration before @@ -1146,6 +1152,7 @@ const char *setup_git_directory_gently(int *nongit_ok) strbuf_release(&dir); strbuf_release(&gitdir); + clear_repository_format(&repo_fmt); return prefix; } @@ -1203,9 +1210,10 @@ int git_config_perm(const char *var, const char *value) void check_repository_format(void) { - struct repository_format repo_fmt; + struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT; check_repository_format_gently(get_git_dir(), &repo_fmt, NULL); startup_info->have_repository = 1; + clear_repository_format(&repo_fmt); } /* diff --git a/worktree.c b/worktree.c index d6a0ee7f73..b45bfeb9d3 100644 --- a/worktree.c +++ b/worktree.c @@ -444,7 +444,7 @@ int submodule_uses_worktrees(const char *path) DIR *dir; struct dirent *d; int ret = 0; - struct repository_format format; + struct repository_format format = REPOSITORY_FORMAT_INIT; submodule_gitdir = git_pathdup_submodule(path, "%s", ""); if (!submodule_gitdir) @@ -462,8 +462,10 @@ int submodule_uses_worktrees(const char *path) read_repository_format(&format, sb.buf); if (format.version != 0) { strbuf_release(&sb); + clear_repository_format(&format); return 1; } + clear_repository_format(&format); /* Replace config by worktrees. */ strbuf_setlen(&sb, sb.len - strlen("config"));