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[PATCH v7 17/38] commit_lock_file(): die() if called for unlocked lockfile object

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Oct 1, 2014, 10:28 UTC
Message-ID
<1412159322-2622-18-git-send-email-mhagger@alum.mit.edu>
In-Reply-To
<1412159322-2622-1-git-send-email-mhagger@alum.mit.edu>

It was previously a bug to call commit_lock_file() with a lock_file object that was not active (an illegal access would happen within the function). It was presumably never done, but this would be an easy programming error to overlook. So before continuing, do a consistency check that the lock_file object really is locked.

Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/technical/api-lockfile.txt | 3 ++-
 lockfile.c                               | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/Documentation/technical/api-lockfile.txt b/Documentation/technical/api-lockfile.txt
index 99830f3..6538610 100644
--- a/Documentation/technical/api-lockfile.txt
+++ b/Documentation/technical/api-lockfile.txt
@@ -147,7 +147,8 @@ commit_lock_file::
 	`hold_lock_file_for_append`, close the file descriptor and
 	rename the lockfile to its final destination. Return 0 upon
 	success or a negative value on failure to `close(2)` or
-	`rename(2)`.
+	`rename(2)`. It is a bug to call `commit_lock_file()` for a
+	`lock_file` object that is not currently locked.
 
 rollback_lock_file::
 
diff --git a/lockfile.c b/lockfile.c
index e148227..c897dd8 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -301,6 +301,9 @@ int commit_lock_file(struct lock_file *lk)
 {
 	char result_file[PATH_MAX];
 
+	if (!lk->filename[0])
+		die("BUG: attempt to commit unlocked object");
+
 	if (close_lock_file(lk))
 		return -1;
 

-- 
2.1.0
Previous: Michael HaggertyNext: Michael Haggerty
Message 21 of 43 in “Lockfile correctness and refactoring”
  1. 00/38 Lockfile correctness and refactoringMichael Haggerty, Oct 1, 2014
  2. 01/38 unable_to_lock_die(): rename function from unable_to_lock_index_die()Michael Haggerty, Oct 1, 2014
  3. 02/38 api-lockfile: revise and expand the documentationMichael Haggerty, Oct 1, 2014
  4. 03/38 close_lock_file(): exit (successfully) if file is already closedMichael Haggerty, Oct 1, 2014
  5. 04/38 rollback_lock_file(): do not clear filename redundantlyMichael Haggerty, Oct 1, 2014
  6. 05/38 rollback_lock_file(): exit early if lock is not activeMichael Haggerty, Oct 1, 2014
  7. 06/38 rollback_lock_file(): set fd to -1Michael Haggerty, Oct 1, 2014
  8. 07/38 lockfile: unlock file if lockfile permissions cannot be adjustedMichael Haggerty, Oct 1, 2014
  9. 08/38 hold_lock_file_for_append(): release lock on errorsMichael Haggerty, Oct 1, 2014
  10. 09/38 lock_file(): always initialize and register lock_file objectMichael Haggerty, Oct 1, 2014
  11. René ScharfeOct 1, 2014
  12. Michael HaggertyOct 1, 2014
  13. Junio C HamanoOct 1, 2014
  14. 10/38 lockfile.c: document the various states of lock_file objectsMichael Haggerty, Oct 1, 2014
  15. 11/38 cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LENMichael Haggerty, Oct 1, 2014
  16. 12/38 delete_ref_loose(): don't muck around in the lock_file's filenameMichael Haggerty, Oct 1, 2014
  17. 13/38 prepare_index(): declare return value to be (const char *)Michael Haggerty, Oct 1, 2014
  18. 14/38 lock_file(): exit early if lockfile cannot be openedMichael Haggerty, Oct 1, 2014
  19. 15/38 remove_lock_file(): call rollback_lock_file()Michael Haggerty, Oct 1, 2014
  20. 16/38 commit_lock_file(): inline temporary variableMichael Haggerty, Oct 1, 2014
  21. 17/38 commit_lock_file(): die() if called for unlocked lockfile objectMichael Haggerty, Oct 1, 2014
  22. 18/38 close_lock_file(): if close fails, roll backMichael Haggerty, Oct 1, 2014
  23. 19/38 commit_lock_file(): rollback lock file on failure to renameMichael Haggerty, Oct 1, 2014
  24. 20/38 api-lockfile: document edge casesMichael Haggerty, Oct 1, 2014
  25. 21/38 dump_marks(): remove a redundant call to rollback_lock_file()Michael Haggerty, Oct 1, 2014
  26. 22/38 git_config_set_multivar_in_file(): avoid call to rollback_lock_file()Michael Haggerty, Oct 1, 2014
  27. 23/38 lockfile: avoid transitory invalid statesMichael Haggerty, Oct 1, 2014
  28. 24/38 struct lock_file: declare some fields volatileMichael Haggerty, Oct 1, 2014
  29. 25/38 try_merge_strategy(): remove redundant lock_file allocationMichael Haggerty, Oct 1, 2014
  30. 26/38 try_merge_strategy(): use a statically-allocated lock_file objectMichael Haggerty, Oct 1, 2014
  31. 27/38 commit_lock_file(): use a strbuf to manage temporary spaceMichael Haggerty, Oct 1, 2014
  32. 28/38 Change lock_file::filename into a strbufMichael Haggerty, Oct 1, 2014
  33. 29/38 resolve_symlink(): use a strbuf for internal scratch spaceMichael Haggerty, Oct 1, 2014
  34. 30/38 resolve_symlink(): take a strbuf parameterMichael Haggerty, Oct 1, 2014
  35. 31/38 trim_last_path_component(): replace last_path_elm()Michael Haggerty, Oct 1, 2014
  36. 32/38 Extract a function commit_lock_file_to()Michael Haggerty, Oct 1, 2014
  37. 33/38 Rename LOCK_NODEREF to LOCK_NO_DEREFMichael Haggerty, Oct 1, 2014
  38. 34/38 lockfile.c: rename static functionsMichael Haggerty, Oct 1, 2014
  39. 35/38 get_locked_file_path(): new functionMichael Haggerty, Oct 1, 2014
  40. 36/38 hold_lock_file_for_append(): restore errno before returningMichael Haggerty, Oct 1, 2014
  41. 37/38 Move read_index() definition to read-cache.cMichael Haggerty, Oct 1, 2014
  42. 38/38 lockfile.h: extract new header file for the functions in lockfile.cMichael Haggerty, Oct 1, 2014
  43. Junio C HamanoOct 1, 2014

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