[PATCH 5/5] shallow: use struct 'shallow_lock' for additional safety
- From
Taylor Blau <me@ttaylorr.com>
- Date
- Apr 29, 2020, 22:39 UTC
- Message-ID
- <c0dc5024a9b368dfbca99b81bc843f66d725f3d7.1588199705.git.me@ttaylorr.com>
- In-Reply-To
- <cover.1588199705.git.me@ttaylorr.com>
In previous patches, the functions 'commit_shallow_file' and 'rollback_shallow_file' were introduced to reset the shallowness validity checks on a repository after potentially modifying '.git/shallow'.
These functions can be made safer by wrapping the 'struct lockfile *' in a new type, 'shallow_lock', so that they cannot be called with a raw lock (and potentially misused by other code that happens to possess a lockfile, but has nothing to do with shallowness).
This patch introduces that type as a thin wrapper around 'struct lockfile', and updates the two aforementioned functions and their callers to use it.
Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> --- builtin/receive-pack.c | 2 +- fetch-pack.c | 2 +- shallow.c | 22 +++++++++++----------- shallow.h | 16 +++++++++++++--- 4 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 652661fa99..10fd2c52ec 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -855,7 +855,7 @@ static void refuse_unconfigured_deny_delete_current(void) static int command_singleton_iterator(void *cb_data, struct object_id *oid); static int update_shallow_ref(struct command *cmd, struct shallow_info *si) { - struct lock_file shallow_lock = LOCK_INIT; + struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT; struct oid_array extra = OID_ARRAY_INIT; struct check_connected_options opt = CHECK_CONNECTED_INIT; uint32_t mask = 1 << (cmd->index % 32); diff --git a/fetch-pack.c b/fetch-pack.c index 401d028e41..27d2d08cc0 100644 --- a/fetch-pack.c +++ b/fetch-pack.c @@ -35,7 +35,7 @@ static int fetch_fsck_objects = -1; static int transfer_fsck_objects = -1; static int agent_supported; static int server_supports_filtering; -static struct lock_file shallow_lock; +static struct shallow_lock shallow_lock; static const char *alternate_shallow_file; static struct strbuf fsck_msg_types = STRBUF_INIT; diff --git a/shallow.c b/shallow.c index 76e00893fe..1acf8ce95b 100644 --- a/shallow.c +++ b/shallow.c @@ -92,16 +92,16 @@ static void reset_repository_shallow(struct repository *r) stat_validity_clear(r->parsed_objects->shallow_stat); } -int commit_shallow_file(struct repository *r, struct lock_file *lk) +int commit_shallow_file(struct repository *r, struct shallow_lock *lk) { - int res = commit_lock_file(lk); + int res = commit_lock_file(&lk->lk); reset_repository_shallow(r); return res; } -void rollback_shallow_file(struct repository *r, struct lock_file *lk) +void rollback_shallow_file(struct repository *r, struct shallow_lock *lk) { - rollback_lock_file(lk); + rollback_lock_file(&lk->lk); reset_repository_shallow(r); } @@ -366,22 +366,22 @@ const char *setup_temporary_shallow(const struct oid_array *extra) return ""; } -void setup_alternate_shallow(struct lock_file *shallow_lock, +void setup_alternate_shallow(struct shallow_lock *shallow_lock, const char **alternate_shallow_file, const struct oid_array *extra) { struct strbuf sb = STRBUF_INIT; int fd; - fd = hold_lock_file_for_update(shallow_lock, + fd = hold_lock_file_for_update(&shallow_lock->lk, git_path_shallow(the_repository), LOCK_DIE_ON_ERROR); check_shallow_file_for_update(the_repository); if (write_shallow_commits(&sb, 0, extra)) { if (write_in_full(fd, sb.buf, sb.len) < 0) die_errno("failed to write to %s", - get_lock_file_path(shallow_lock)); - *alternate_shallow_file = get_lock_file_path(shallow_lock); + get_lock_file_path(&shallow_lock->lk)); + *alternate_shallow_file = get_lock_file_path(&shallow_lock->lk); } else /* * is_repository_shallow() sees empty string as "no @@ -414,7 +414,7 @@ void advertise_shallow_grafts(int fd) */ void prune_shallow(unsigned options) { - struct lock_file shallow_lock = LOCK_INIT; + struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT; struct strbuf sb = STRBUF_INIT; unsigned flags = SEEN_ONLY; int fd; @@ -428,14 +428,14 @@ void prune_shallow(unsigned options) strbuf_release(&sb); return; } - fd = hold_lock_file_for_update(&shallow_lock, + fd = hold_lock_file_for_update(&shallow_lock.lk, git_path_shallow(the_repository), LOCK_DIE_ON_ERROR); check_shallow_file_for_update(the_repository); if (write_shallow_commits_1(&sb, 0, NULL, flags)) { if (write_in_full(fd, sb.buf, sb.len) < 0) die_errno("failed to write to %s", - get_lock_file_path(&shallow_lock)); + get_lock_file_path(&shallow_lock.lk)); commit_shallow_file(the_repository, &shallow_lock); } else { unlink(git_path_shallow(the_repository)); diff --git a/shallow.h b/shallow.h index 08e1bc4fd0..d12096fbc4 100644 --- a/shallow.h +++ b/shallow.h @@ -10,12 +10,22 @@ void set_alternate_shallow_file(struct repository *r, const char *path, int over int register_shallow(struct repository *r, const struct object_id *oid); int unregister_shallow(const struct object_id *oid); int is_repository_shallow(struct repository *r); + +/* + * shallow_lock is a thin wrapper around 'struct lock_file' in order to restrict + * which locks can be used with '{commit,rollback}_shallow_file()'. + */ +struct shallow_lock { + struct lock_file lk; +}; +#define SHALLOW_LOCK_INIT { LOCK_INIT } + /* * {commit,rollback}_shallow_file commits or performs a rollback to the * '.git/shallow' file, respectively, and resets stat-validity checks. */ -int commit_shallow_file(struct repository *r, struct lock_file *lk); -void rollback_shallow_file(struct repository *r, struct lock_file *lk); +int commit_shallow_file(struct repository *r, struct shallow_lock *lk); +void rollback_shallow_file(struct repository *r, struct shallow_lock *lk); struct commit_list *get_shallow_commits(struct object_array *heads, int depth, int shallow_flag, int not_shallow_flag); @@ -24,7 +34,7 @@ struct commit_list *get_shallow_commits_by_rev_list( int write_shallow_commits(struct strbuf *out, int use_pack_protocol, const struct oid_array *extra); -void setup_alternate_shallow(struct lock_file *shallow_lock, +void setup_alternate_shallow(struct shallow_lock *shallow_lock, const char **alternate_shallow_file, const struct oid_array *extra);
-- 2.26.0.113.ge9739cdccc