Adds a compatibility wrapper around os.fork() that backports the ability
to register fork event handlers (os.register_at_fork()) from Python 3.7
[YOCTO #13030]
Signed-off-by: Joshua Watt <jpewhac...@gmail.com>
---
bitbake/bin/bitbake-worker | 2 +-
bitbake/lib/bb/fork.py | 73 ++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+), 1 deletion(-)
create mode 100644 bitbake/lib/bb/fork.py
diff --git a/bitbake/bin/bitbake-worker b/bitbake/bin/bitbake-worker
index cd687e6e433..41ef6d848ac 100755
--- a/bitbake/bin/bitbake-worker
+++ b/bitbake/bin/bitbake-worker
@@ -181,7 +181,7 @@ def fork_off_task(cfg, data, databuilder, workerdata, fn,
task, taskname, taskha
pipein, pipeout = os.pipe()
pipein = os.fdopen(pipein, 'rb', 4096)
pipeout = os.fdopen(pipeout, 'wb', 0)
- pid = os.fork()
+ pid = bb.fork.fork()
except OSError as e:
logger.critical("fork failed: %d (%s)" % (e.errno, e.strerror))
sys.exit(1)
diff --git a/bitbake/lib/bb/fork.py b/bitbake/lib/bb/fork.py
new file mode 100644
index 00000000000..2b2b0b73b62
--- /dev/null
+++ b/bitbake/lib/bb/fork.py
@@ -0,0 +1,73 @@
+# ex:ts=4:sw=4:sts=4:et
+# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#
+# Copyright (C) 2018 Garmin Ltd.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+"""
+Python wrappers for os.fork() that allow the insertion of callbacks for fork
events.
+This is designed to exacmimic os.register_at_fork() available in Python 3.7
with the
+intent that it can be removed when that version becomes standard
+"""
+
+import sys
+import os
+
+before_calls = []
+after_in_parent_calls = []
+after_in_child_calls = []
+
+def _do_calls(l, reverse=False):
+ # Make a copy in case the list is modified in the callback
+ copy = l[:]
+ if reverse:
+ copy = reversed(copy)
+
+ for f in copy:
+ # All exception in calls are ignored
+ try:
+ f()
+ except:
+ pass
+
+def fork():
+ if sys.hexversion >= 0x030700F0:
+ return os.fork()
+
+ _do_calls(before_calls, reverse=True)
+
+ ret = os.fork()
+ if ret == 0:
+ _do_calls(after_in_child_calls)
+ else:
+ _do_calls(after_in_parent_calls)
+ return ret
+
+def register_at_fork(**kwargs):
+ def add_arg_to_list(name, lst):
+ if name in kwargs:
+ arg = kwargs[name]
+ if not callable(arg):
+ raise TypeError("'%s' must be callable, not %s" % (name,
type(arg)))
+ lst.append(arg)
+
+ if sys.hexversion >= 0x030700F0:
+ os.register_at_fork(**kwargs)
+ return
+
+ add_arg_to_list('before', before_calls)
+ add_arg_to_list('after_in_parent', after_in_parent_calls)
+ add_arg_to_list('after_in_child', after_in_child_calls)
+
--
2.19.2
--
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