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[PATCH v21 14/19] refs.c: log_ref_write should try to return meaningful errno

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jul 14, 2014, 20:58 UTC
Message-ID
<1405371541-32121-15-git-send-email-sahlberg@google.com>
In-Reply-To
<1405371541-32121-1-git-send-email-sahlberg@google.com>
Making errno from write_ref_sha1() meaningful, which should fix
* a bug in "git checkout -b" where it prints strerror(errno)
  despite errno possibly being zero or clobbered
* a bug in "git fetch"'s s_update_ref, which trusts the result of an
  errno == ENOTDIR check to detect D/F conflicts
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/refs.c b/refs.c
index 211429d..61570c9 100644
--- a/refs.c
+++ b/refs.c
@@ -2859,8 +2859,19 @@ static int log_ref_write(const char *refname, const unsigned char *old_sha1,
 		len += copy_msg(logrec + len - 1, msg) - 1;
 	written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
 	free(logrec);
-	if (close(logfd) != 0 || written != len)
-		return error("Unable to append to %s", log_file);
+	if (written != len) {
+		int save_errno = errno;
+		close(logfd);
+		error("Unable to append to %s", log_file);
+		errno = save_errno;
+		return -1;
+	}
+	if (close(logfd)) {
+		int save_errno = errno;
+		error("Unable to append to %s", log_file);
+		errno = save_errno;
+		return -1;
+	}
 	return 0;
 }
 
@@ -2869,14 +2880,17 @@ static int is_branch(const char *refname)
 	return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 }
 
+/* This function must return a meaningful errno */
 int write_ref_sha1(struct ref_lock *lock,
 	const unsigned char *sha1, const char *logmsg)
 {
 	static char term = '\n';
 	struct object *o;
 
-	if (!lock)
+	if (!lock) {
+		errno = EINVAL;
 		return -1;
+	}
 	if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
 		unlock_ref(lock);
 		return 0;
@@ -2886,19 +2900,23 @@ int write_ref_sha1(struct ref_lock *lock,
 		error("Trying to write ref %s with nonexistent object %s",
 			lock->ref_name, sha1_to_hex(sha1));
 		unlock_ref(lock);
+		errno = EINVAL;
 		return -1;
 	}
 	if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
 		error("Trying to write non-commit object %s to branch %s",
 			sha1_to_hex(sha1), lock->ref_name);
 		unlock_ref(lock);
+		errno = EINVAL;
 		return -1;
 	}
 	if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
-	    write_in_full(lock->lock_fd, &term, 1) != 1
-		|| close_ref(lock) < 0) {
+	    write_in_full(lock->lock_fd, &term, 1) != 1 ||
+	    close_ref(lock) < 0) {
+		int save_errno = errno;
 		error("Couldn't write %s", lock->lk->filename);
 		unlock_ref(lock);
+		errno = save_errno;
 		return -1;
 	}
 	clear_loose_ref_cache(&ref_cache);

-- 
2.0.1.546.gf603308
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 15 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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