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[PATCH v21 10/19] refs.c: verify_lock should set errno to something meaningful

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jul 14, 2014, 20:58 UTC
Message-ID
<1405371541-32121-11-git-send-email-sahlberg@google.com>
In-Reply-To
<1405371541-32121-1-git-send-email-sahlberg@google.com>

Making errno when returning from verify_lock() meaningful, which should almost but not completely fix

 * a bug in "git fetch"'s s_update_ref, which trusts the result of an
   errno == ENOTDIR check to detect D/F conflicts

ENOTDIR makes sense as a sign that a file was in the way of a directory we wanted to create. Should "git fetch" also look for ENOTEMPTY or EEXIST to catch cases where a directory was in the way of a file to be created?

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs.c | 4 ++++
 refs.h | 6 +++++-
 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/refs.c b/refs.c
index 9ea519c..a48f805 100644
--- a/refs.c
+++ b/refs.c
@@ -1932,18 +1932,22 @@ int refname_match(const char *abbrev_name, const char *full_name)
 	return 0;
 }
 
+/* This function should make sure errno is meaningful on error */
 static struct ref_lock *verify_lock(struct ref_lock *lock,
 	const unsigned char *old_sha1, int mustexist)
 {
 	if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
+		int save_errno = errno;
 		error("Can't verify ref %s", lock->ref_name);
 		unlock_ref(lock);
+		errno = save_errno;
 		return NULL;
 	}
 	if (hashcmp(lock->old_sha1, old_sha1)) {
 		error("Ref %s is at %s but expected %s", lock->ref_name,
 			sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 		unlock_ref(lock);
+		errno = EBUSY;
 		return NULL;
 	}
 	return lock;
diff --git a/refs.h b/refs.h
index 82cc5cb..8d6cac7 100644
--- a/refs.h
+++ b/refs.h
@@ -137,11 +137,15 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/** Locks a "refs/" ref returning the lock on success and NULL on failure. **/
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
 
 /** Locks any ref (for 'HEAD' type refs). */
 #define REF_NODEREF	0x01
+/* errno is set to something meaningful on failure */
 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
 						const unsigned char *old_sha1,
 						int flags, int *type_p);

-- 
2.0.1.546.gf603308
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 11 of 20 in “Use ref transactions”
  1. 00/19 Use ref transactionsRonnie Sahlberg, Jul 14, 2014
  2. 01/19 refs.c: remove ref_transaction_rollbackRonnie Sahlberg, Jul 14, 2014
  3. 02/19 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, Jul 14, 2014
  4. 03/19 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, Jul 14, 2014
  5. 04/19 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, Jul 14, 2014
  6. 05/19 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, Jul 14, 2014
  7. 06/19 lockfile.c: add a new public function unable_to_lock_messageRonnie Sahlberg, Jul 14, 2014
  8. 07/19 lockfile.c: make lock_file return a meaningful errno on failureRonnie Sahlberg, Jul 14, 2014
  9. 08/19 refs.c: add an err argument to repack_without_refsRonnie Sahlberg, Jul 14, 2014
  10. 09/19 refs.c: make sure log_ref_setup returns a meaningful errnoRonnie Sahlberg, Jul 14, 2014
  11. 10/19 refs.c: verify_lock should set errno to something meaningfulRonnie Sahlberg, Jul 14, 2014
  12. 11/19 refs.c: make remove_empty_directories always set errno to something saneRonnie Sahlberg, Jul 14, 2014
  13. 12/19 refs.c: commit_packed_refs to return a meaningful errno on failureRonnie Sahlberg, Jul 14, 2014
  14. 13/19 refs.c: make resolve_ref_unsafe set errno to something meaningful on errorRonnie Sahlberg, Jul 14, 2014
  15. 14/19 refs.c: log_ref_write should try to return meaningful errnoRonnie Sahlberg, Jul 14, 2014
  16. 15/19 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, Jul 14, 2014
  17. 16/19 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, Jul 14, 2014
  18. 17/19 update-ref: use err argument to get error from ref_transaction_commitRonnie Sahlberg, Jul 14, 2014
  19. 18/19 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, Jul 14, 2014
  20. 19/19 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, Jul 14, 2014

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