Bug#575293: [Pkg-freevo-maint] Bug#575293: python-kaa-base: integration with twisted does not work anymore
hi, thanks a lot for the detailed analysis On Wed, Mar 24, 2010 at 09:14:20PM +0100, Mickael Royer wrote: More information : The problem does not appear in version 0.6.0-2 and is due to this diff : diff -ru kaa/process.py kaa--new/process.py [...] yes, this was added in the hope of supporting architectures with different libc When we import kaa, this code is called and ctypes.util.find_library call popen function which force kaa notifier init. do you mean that the call os.popen in line 55 in /usr/lib/python2.5/ctypes/util.py triggers an initialization of kaa notifier ? how does this happen? can it be avoided? a. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#575293: [Pkg-freevo-maint] Bug#575293: python-kaa-base: integration with twisted does not work anymore
Hi, do you mean that the call os.popen in line 55 in /usr/lib/python2.5/ctypes/util.py triggers an initialization of kaa notifier ? how does this happen? It happens like that : 1. import kaa 2. in kaa/__init__.py line 39 from async import ... 3. in kaa/async.py line 977 import main 4. in kaa/main.py line 30 from process import supervisor 5. in kaa/process.py line 182 supervisor = _Supervisor 6. in kaa/process.py line 64 in constructor of _Supervisor : signal.signal(signal.SIGCHLD, self._sigchld_handler) So kaa check SIGHDL (signal sent to a process when a child process terminates). Just after that (in the same function, line 79) we call ctypes.util.find_library which call popen. When popen finished, SIGHDL is raised, so self._sigchld_handler is called and the notifier is initialized. can it be avoided? The solution I see is to load libc library with ctypes just before start to handle SIGHDL signal. I try quickly and it seems to work well. Cheers Mickaël On Thu, Mar 25, 2010 at 9:44 AM, A Mennucc deb...@tonelli.sns.it wrote: hi, thanks a lot for the detailed analysis On Wed, Mar 24, 2010 at 09:14:20PM +0100, Mickael Royer wrote: More information : The problem does not appear in version 0.6.0-2 and is due to this diff : diff -ru kaa/process.py kaa--new/process.py [...] yes, this was added in the hope of supporting architectures with different libc When we import kaa, this code is called and ctypes.util.find_library call popen function which force kaa notifier init. do you mean that the call os.popen in line 55 in /usr/lib/python2.5/ctypes/util.py triggers an initialization of kaa notifier ? how does this happen? can it be avoided? a. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#575293: [Pkg-freevo-maint] Bug#575293: python-kaa-base: integration with twisted does not work anymore
It happens like that :
1. import kaa
2. in kaa/__init__.py line 39 from async import ...
3. in kaa/async.py line 977 import main
4. in kaa/main.py line 30 from process import supervisor
5. in kaa/process.py line 182 supervisor = _Supervisor
6. in kaa/process.py line 64 in constructor of _Supervisor :
signal.signal(signal.SIGCHLD, self._sigchld_handler)
From tonight's investigations, I could get the following backtrace
which is where the timer is started and thus the notifier is said to
be already started.
--
import kaa
File /usr/lib/python2.5/site-packages/kaa/__init__.py, line 39, in module
from async import TimeoutException, InProgress, InProgressCallback, \
File /usr/lib/python2.5/site-packages/kaa/async.py, line 977, in module
import main
File /usr/lib/python2.5/site-packages/kaa/main.py, line 50, in module
from process import supervisor
File /usr/lib/python2.5/site-packages/kaa/process.py, line 182, in module
supervisor = _Supervisor()
File /usr/lib/python2.5/site-packages/kaa/process.py, line 79, in __init__
libc=ctypes.util.find_library('c')
File /usr/lib/python2.5/ctypes/util.py, line 164, in find_library
return _findSoname_ldconfig(name) or _get_soname(_findLib_gcc(name))
File /usr/lib/python2.5/ctypes/util.py, line 158, in _findSoname_ldconfig
os.popen('LANG=C /sbin/ldconfig -p 2/dev/null').read())
File /usr/lib/python2.5/site-packages/kaa/timer.py, line 96, in newfunc
t.start(interval)
--
Now, this is in the @timed decorator from kaa.timer and using a dirty
print statement, I could get the only decorated function name which is
_sigchld_handler . This signal is triggered, because the ldconfig
child process terminates.
Knowing this, a working fix, as said, is as simple as delaying the
signal setting, as shown by the attached patch, which works.
Cheers,
Alex
diff -Nru kaa-base-0.6.0/src/process.py kaa-base-0.6.0.new//src/process.py
--- kaa-base-0.6.0/src/process.py 2010-03-25 23:04:04.0 +0100
+++ kaa-base-0.6.0.new//src/process.py 2010-03-25 23:15:37.0 +0100
@@ -61,7 +61,6 @@
def __init__(self):
self.processes = {}
-signal.signal(signal.SIGCHLD, self._sigchld_handler)
# Set SA_RESTART bit for the signal, which restarts any interrupted
# system calls -- however, select (at least on Linux) is NOT restarted
# for reasons described at:
@@ -72,11 +71,15 @@
v = sys.version_info
if v[0] = 3 or (v[0] == 2 and v[1] = 6):
# Python 2.6+
+signal.signal(signal.SIGCHLD, self._sigchld_handler)
signal.siginterrupt(signal.SIGCHLD, False)
elif v[0] == 2 and v[1] == 5:
# Python 2.5
import ctypes, ctypes.util
libc=ctypes.util.find_library('c')
+# ctypes.util.find_library() involves a child process, so the
+# hanler should be set after the call.
+signal.signal(signal.SIGCHLD, self._sigchld_handler)
ctypes.CDLL(libc).siginterrupt(signal.SIGCHLD, 0)
else:
# Python 2.4- is not supported.
