git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v21 07/19] lockfile.c: make lock_file return a meaningful errno on failure

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jul 14, 2014, 20:58 UTC
Message-ID
<1405371541-32121-8-git-send-email-sahlberg@google.com>
In-Reply-To
<1405371541-32121-1-git-send-email-sahlberg@google.com>

Making errno when returning from lock_file() meaningful, which should fix

 * an existing almost-bug in lock_ref_sha1_basic where it assumes
   errno==ENOENT is meaningful and could waste some work on retries
 * an existing bug in repack_without_refs where it prints
   strerror(errno) and picks advice based on errno, despite errno
   potentially being zero and potentially having been clobbered by
   that point
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 lockfile.c | 17 ++++++++++++-----
 refs.c     |  1 +
 refs.h     |  1 +
 3 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/lockfile.c b/lockfile.c
index 464031b..a921d77 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -121,7 +121,7 @@ static char *resolve_symlink(char *p, size_t s)
 	return p;
 }
 
-
+/* Make sure errno contains a meaningful value on error */
 static int lock_file(struct lock_file *lk, const char *path, int flags)
 {
 	/*
@@ -130,8 +130,10 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	 */
 	static const size_t max_path_len = sizeof(lk->filename) - 5;
 
-	if (strlen(path) >= max_path_len)
+	if (strlen(path) >= max_path_len) {
+		errno = ENAMETOOLONG;
 		return -1;
+	}
 	strcpy(lk->filename, path);
 	if (!(flags & LOCK_NODEREF))
 		resolve_symlink(lk->filename, max_path_len);
@@ -148,9 +150,13 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 			lock_file_list = lk;
 			lk->on_list = 1;
 		}
-		if (adjust_shared_perm(lk->filename))
-			return error("cannot fix permission bits on %s",
-				     lk->filename);
+		if (adjust_shared_perm(lk->filename)) {
+			int save_errno = errno;
+			error("cannot fix permission bits on %s",
+			      lk->filename);
+			errno = save_errno;
+			return -1;
+		}
 	}
 	else
 		lk->filename[0] = 0;
@@ -188,6 +194,7 @@ NORETURN void unable_to_lock_index_die(const char *path, int err)
 	die("%s", buf.buf);
 }
 
+/* This should return a meaningful errno on failure */
 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
 {
 	int fd = lock_file(lk, path, flags);
diff --git a/refs.c b/refs.c
index db05602..e9d53e4 100644
--- a/refs.c
+++ b/refs.c
@@ -2212,6 +2212,7 @@ static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
 	return 0;
 }
 
+/* This should return a meaningful errno on failure */
 int lock_packed_refs(int flags)
 {
 	struct packed_ref_cache *packed_ref_cache;
diff --git a/refs.h b/refs.h
index 09d3564..64f25d9 100644
--- a/refs.h
+++ b/refs.h
@@ -82,6 +82,7 @@ extern void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct st
 /*
  * Lock the packed-refs file for writing.  Flags is passed to
  * hold_lock_file_for_update().  Return 0 on success.
+ * Errno is set to something meaningful on error.
  */
 extern int lock_packed_refs(int flags);
 

-- 
2.0.1.546.gf603308
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 8 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

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.