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authorTaylor Blau <me@ttaylorr.com>2020-04-30 19:48:57 (GMT)
committerJunio C Hamano <gitster@pobox.com>2020-04-30 21:19:13 (GMT)
commitcac4b8e22ee39e52341d718450f8e4055c4dc16f (patch)
treea9f706e5504f65230a96e94fa8f320b518455a07
parenta4101617688ad504d06b4cc007430c406640e934 (diff)
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shallow: use struct 'shallow_lock' for additional safety
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> Helped-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--builtin/receive-pack.c2
-rw-r--r--fetch-pack.c2
-rw-r--r--shallow.c22
-rw-r--r--shallow.h21
4 files changed, 31 insertions, 16 deletions
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 8e3f9bc..73cebc2 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -856,7 +856,7 @@ 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 401d028..27d2d08 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 76e0089..7e0a41e 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->lock);
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->lock);
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->lock,
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->lock));
+ *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
} 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.lock,
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.lock));
commit_shallow_file(the_repository, &shallow_lock);
} else {
unlink(git_path_shallow(the_repository));
diff --git a/shallow.h b/shallow.h
index b3bf200..5b4a96d 100644
--- a/shallow.h
+++ b/shallow.h
@@ -10,10 +10,25 @@ 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);
+
+/*
+ * Lock for updating the $GIT_DIR/shallow file.
+ *
+ * Use `commit_shallow_file()` to commit an update, or
+ * `rollback_shallow_file()` to roll it back. In either case, any
+ * in-memory cached information about which commits are shallow will be
+ * appropriately invalidated so that future operations reflect the new
+ * state.
+ */
+struct shallow_lock {
+ struct lock_file lock;
+};
+#define SHALLOW_LOCK_INIT { LOCK_INIT }
+
/* commit $GIT_DIR/shallow and reset stat-validity checks */
-int commit_shallow_file(struct repository *r, struct lock_file *lk);
+int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
/* rollback $GIT_DIR/shallow and reset stat-validity checks */
-void rollback_shallow_file(struct repository *r, struct lock_file *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);
@@ -22,7 +37,7 @@ 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);