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authorRichard Purdie <richard.purdie@linuxfoundation.org>2015-09-08 23:31:13 +0100
committerRichard Purdie <richard.purdie@linuxfoundation.org>2015-09-09 14:27:56 +0100
commit289007e5ebd82e7cf61a20c6afd0206e0037ce0d (patch)
tree2196b8e402558499cbf2e54c2f9880b4e52de798 /bitbake/lib
parent384533bdb47af2c3a0f3faea8879e8f3cb6f39f9 (diff)
downloadpoky-289007e5ebd82e7cf61a20c6afd0206e0037ce0d.tar.gz
bitbake: utils: Add signal_on_parent_exit() function
Add a new bb.utils.signal_on_parent_exit() function so that a process can register to recieve a signal when the parent dies. There is no POSIX standard for this and the implementation is Linux specific. Alternatives would be having an open pipe or polling os.getppid() for changes but this seems more effective and less invasive to most of bitbake's code structure. We need to be able to determine when parents die to ensure child processes stop running in a variety of circumstances to avoid locks being held and ensure clean shutdown. Roughly based on https://gist.github.com/evansd/2346614 (Bitbake rev: 34974f5e30e9b09c016481e4c81c156a5f379784) Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'bitbake/lib')
-rw-r--r--bitbake/lib/bb/utils.py19
1 files changed, 19 insertions, 0 deletions
diff --git a/bitbake/lib/bb/utils.py b/bitbake/lib/bb/utils.py
index b62985dd7b..91faa494ca 100644
--- a/bitbake/lib/bb/utils.py
+++ b/bitbake/lib/bb/utils.py
@@ -35,6 +35,8 @@ import errno
35import signal 35import signal
36from commands import getstatusoutput 36from commands import getstatusoutput
37from contextlib import contextmanager 37from contextlib import contextmanager
38from ctypes import cdll
39
38 40
39logger = logging.getLogger("BitBake.Util") 41logger = logging.getLogger("BitBake.Util")
40 42
@@ -1291,3 +1293,20 @@ def get_file_layer(filename, d):
1291 result = path_to_layer(filename) 1293 result = path_to_layer(filename)
1292 1294
1293 return result 1295 return result
1296
1297
1298# Constant taken from http://linux.die.net/include/linux/prctl.h
1299PR_SET_PDEATHSIG = 1
1300
1301class PrCtlError(Exception):
1302 pass
1303
1304def signal_on_parent_exit(signame):
1305 """
1306 Trigger signame to be sent when the parent process dies
1307 """
1308 signum = getattr(signal, signame)
1309 # http://linux.die.net/man/2/prctl
1310 result = cdll['libc.so.6'].prctl(PR_SET_PDEATHSIG, signum)
1311 if result != 0:
1312 raise PrCtlError('prctl failed with error code %s' % result)