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>
Taylor Blau committed
Apr 30, 2020 at 13:48 UTC
cac4b8e22ee39e52341d718450f8e4055c4dc16f
4 files changed
+31
-16
builtin/receive-pack.c
+1
-1
@@ -856,7 +856,7 @@ static void refuse_unconfigured_deny_delete_current(void)
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static int command_singleton_iterator(void *cb_data, struct object_id *oid);
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static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
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{
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- struct lock_file shallow_lock = LOCK_INIT;
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+ struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
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struct oid_array extra = OID_ARRAY_INIT;
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struct check_connected_options opt = CHECK_CONNECTED_INIT;
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uint32_t mask = 1 << (cmd->index % 32);
fetch-pack.c
+1
-1
@@ -35,7 +35,7 @@ static int fetch_fsck_objects = -1;
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static int transfer_fsck_objects = -1;
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static int agent_supported;
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static int server_supports_filtering;
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-static struct lock_file shallow_lock;
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+static struct shallow_lock shallow_lock;
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static const char *alternate_shallow_file;
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static struct strbuf fsck_msg_types = STRBUF_INIT;
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shallow.c
+11
-11
@@ -92,16 +92,16 @@ static void reset_repository_shallow(struct repository *r)
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stat_validity_clear(r->parsed_objects->shallow_stat);
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}
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-int commit_shallow_file(struct repository *r, struct lock_file *lk)
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+int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
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{
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- int res = commit_lock_file(lk);
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+ int res = commit_lock_file(&lk->lock);
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reset_repository_shallow(r);
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return res;
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}
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-void rollback_shallow_file(struct repository *r, struct lock_file *lk)
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+void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
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{
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- rollback_lock_file(lk);
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+ rollback_lock_file(&lk->lock);
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reset_repository_shallow(r);
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}
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@@ -366,22 +366,22 @@ const char *setup_temporary_shallow(const struct oid_array *extra)
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return "";
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}
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-void setup_alternate_shallow(struct lock_file *shallow_lock,
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+void setup_alternate_shallow(struct shallow_lock *shallow_lock,
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const char **alternate_shallow_file,
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const struct oid_array *extra)
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{
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struct strbuf sb = STRBUF_INIT;
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int fd;
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- fd = hold_lock_file_for_update(shallow_lock,
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+ fd = hold_lock_file_for_update(&shallow_lock->lock,
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git_path_shallow(the_repository),
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LOCK_DIE_ON_ERROR);
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check_shallow_file_for_update(the_repository);
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if (write_shallow_commits(&sb, 0, extra)) {
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if (write_in_full(fd, sb.buf, sb.len) < 0)
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die_errno("failed to write to %s",
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- get_lock_file_path(shallow_lock));
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- *alternate_shallow_file = get_lock_file_path(shallow_lock);
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+ get_lock_file_path(&shallow_lock->lock));
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+ *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
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} else
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/*
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* is_repository_shallow() sees empty string as "no
@@ -414,7 +414,7 @@ void advertise_shallow_grafts(int fd)
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*/
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void prune_shallow(unsigned options)
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{
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- struct lock_file shallow_lock = LOCK_INIT;
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+ struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
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struct strbuf sb = STRBUF_INIT;
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unsigned flags = SEEN_ONLY;
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int fd;
@@ -428,14 +428,14 @@ void prune_shallow(unsigned options)
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strbuf_release(&sb);
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return;
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}
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- fd = hold_lock_file_for_update(&shallow_lock,
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+ fd = hold_lock_file_for_update(&shallow_lock.lock,
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git_path_shallow(the_repository),
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LOCK_DIE_ON_ERROR);
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check_shallow_file_for_update(the_repository);
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if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
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if (write_in_full(fd, sb.buf, sb.len) < 0)
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die_errno("failed to write to %s",
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- get_lock_file_path(&shallow_lock));
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+ get_lock_file_path(&shallow_lock.lock));
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commit_shallow_file(the_repository, &shallow_lock);
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} else {
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unlink(git_path_shallow(the_repository));
shallow.h
+18
-3
@@ -10,10 +10,25 @@ void set_alternate_shallow_file(struct repository *r, const char *path, int over
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int register_shallow(struct repository *r, const struct object_id *oid);
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int unregister_shallow(const struct object_id *oid);
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int is_repository_shallow(struct repository *r);
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+
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+/*
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+ * Lock for updating the $GIT_DIR/shallow file.
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+ *
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+ * Use `commit_shallow_file()` to commit an update, or
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+ * `rollback_shallow_file()` to roll it back. In either case, any
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+ * in-memory cached information about which commits are shallow will be
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+ * appropriately invalidated so that future operations reflect the new
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+ * state.
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+ */
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+struct shallow_lock {
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+ struct lock_file lock;
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+};
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+#define SHALLOW_LOCK_INIT { LOCK_INIT }
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+
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/* commit $GIT_DIR/shallow and reset stat-validity checks */
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-int commit_shallow_file(struct repository *r, struct lock_file *lk);
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+int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
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/* rollback $GIT_DIR/shallow and reset stat-validity checks */
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-void rollback_shallow_file(struct repository *r, struct lock_file *lk);
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+void rollback_shallow_file(struct repository *r, struct shallow_lock *lk);
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struct commit_list *get_shallow_commits(struct object_array *heads,
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int depth, int shallow_flag, int not_shallow_flag);
@@ -22,7 +37,7 @@ struct commit_list *get_shallow_commits_by_rev_list(
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int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
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const struct oid_array *extra);
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25
-void setup_alternate_shallow(struct lock_file *shallow_lock,
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+void setup_alternate_shallow(struct shallow_lock *shallow_lock,
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const char **alternate_shallow_file,
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const struct oid_array *extra);
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