[PATCH] utils: Add workaround for multiprocessing bug

[Richard Purdie <richard.purdie@linuxfoundation.org>]

Our usage of multitprocessing is problematic. In particular, there is a bug
in python 2.7 multiprocessing where signals are not handled until command
completion instead of immediately.

This adds a workaround into our wrapper function to deal with the issue.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/bitbake/lib/bb/utils.py b/bitbake/lib/bb/utils.py
index 781af3a..11f046a 100644
--- a/bitbake/lib/bb/utils.py
+++ b/bitbake/lib/bb/utils.py
@@ -883,5 +883,17 @@ def process_profilelog(fn):
 # Was present to work around multiprocessing pool bugs in python < 2.7.3
 #
 def multiprocessingpool(*args, **kwargs):
+
+    import multiprocessing.pool
+    #import multiprocessing.util
+    #multiprocessing.util.log_to_stderr(10)
+    # Deal with a multiprocessing bug where signals to the processes would be delayed until the work
+    # completes. Putting in a timeout means the signals (like SIGINT/SIGTERM) get processed.
+    def wrapper(func):
+        def wrap(self, timeout=None):
+            return func(self, timeout=timeout if timeout is not None else 1e100)
+        return wrap
+    multiprocessing.pool.IMapIterator.next = wrapper(multiprocessing.pool.IMapIterator.next)
+
     return multiprocessing.Pool(*args, **kwargs)