setup: fix memory leaks with `struct repository_format`
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. Thus,
it is important to initialize the struct before calling `read_...()`, so
document that. It's also important because we might not even call
`read_...()` before we call `clear_...()`, see, e.g., builtin/init-db.c.
Teach `read_...()` to clear the struct on error, so that it is reset to
a safe state, and document this. (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 <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/setup.c b/setup.c
index bb63394..ab6e8fd 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);
@@ -500,27 +500,38 @@ 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;
}
+static void init_repository_format(struct repository_format *format)
+{
+ const struct repository_format fresh = REPOSITORY_FORMAT_INIT;
+
+ memcpy(format, &fresh, sizeof(fresh));
+}
+
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);
+ init_repository_format(format);
+}
+
int verify_repository_format(const struct repository_format *format,
struct strbuf *err)
{
@@ -1008,7 +1019,7 @@ 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 +1056,11 @@ 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 +1069,7 @@ 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 +1159,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
strbuf_release(&dir);
strbuf_release(&gitdir);
+ clear_repository_format(&repo_fmt);
return prefix;
}
@@ -1203,9 +1217,10 @@ 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);
}
/*
