[patch] _get_lock_fn: test fcntl.flock and hardlink_lockfile

_get_lock_fn-test-fcntl.flock-and-hardlink_lockfile.patch (text/plain), 1.24 KB, created by Zac Medico on 2021-03-06 08:36:49 UTC

From d06db1fb33f50ea47dbf84016ca80d70a5f840c1 Mon Sep 17 00:00:00 2001
From: Zac Medico <[e-mail]>
Date: Sat, 6 Mar 2021 00:25:16 -0800
Subject: [PATCH] _get_lock_fn: test fcntl.flock and hardlink_lockfile

TODO: Add fallback to handle missing hardlink permission for android.

Bug: https://bugs.gentoo.org/774384
Signed-off-by: Zac Medico <[e-mail]>
---
 lib/portage/locks.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/lib/portage/locks.py b/lib/portage/locks.py
index 4d0eede50..b1670fe5c 100644
--- a/lib/portage/locks.py
+++ b/lib/portage/locks.py
@@ -54,6 +54,23 @@ def _get_lock_fn():
 		_lock_fn = fcntl.lockf
 		return _lock_fn
 
+	if _test_lock_fn(
+		lambda path, fd, flags: functools.partial(
+			unlockfile, (path, fcntl.flock(fd, flags), 0, fcntl.flock)
+		)
+	):
+		_lock_fn = fcntl.flock
+		return _lock_fn
+
+	if not _test_lock_fn(
+		lambda path, fd, flags: hardlink_lockfile(
+			path, flags=(os.O_NONBLOCK if flags & fcntl.LOCK_NB else 0)
+		)
+		and functools.partial(unlockfile, (path, HARDLINK_FD, 0, None))
+	):
+		# TODO: Add fallback to handle missing hardlink permission for android (bug 774384)
+		pass
+
 	# Fall back to fcntl.flock.
 	_lock_fn = fcntl.flock
 	return _lock_fn
-- 
2.26.2