fcntl and siginfo_t in python

[ma]

 Here's something that I came up with so far, I'm having some issues with
segfaulting, if I want to pass a struct member by ref in ctypes(see below),
if not, I just get a
"Real-time signal 0" sent back to me.

Any ideas?

#!/usr/bin/env python import os, sys, re
try: import fcntl
except ImportError:
 raise OSError, "Only runs on unix!"
 import signal from ctypes import * #ugh, but just for this exercise from
ctypes import util ####################################### # sigaction /
siginfo structs ####################################### # struct sigaction {
# void (*sa_handler)(int); # void (*sa_sigaction)(int, siginfo_t *, void *);
# sigset_t sa_mask; # int sa_flags; # void (*sa_restorer)(void); # }
###################################### class sigval(Union): _fields_ = [
('sival_int', c_int), ('sival_ptr', c_void_p), ] class __siginfo(Structure):
_fields_ = [ ('si_signo', c_int), ('si_errno', c_int), ('si_code', c_int),
('si_pid', c_uint), ('si_uid', c_uint), ('si_status', c_int), ('si_addr',
c_void_p), ('si_value', sigval), ('si_band', c_long), ('pad', c_ulong * 7),
] siginfo_t = __siginfo class __sigaction_u(Union): _fields_ = [
('__sa_handler', CFUNCTYPE(None, c_int)), ('__sa_sigaction', CFUNCTYPE(None,
c_int,  POINTER(siginfo_t),
 c_void_p)), ] sigaction_u = __sigaction_u class __sigaction(Structure):
_fields_ = [ ('__sigaction_u',sigaction_u), ('sa_tramp', CFUNCTYPE(None,
c_void_p,
c_int, c_int,
 POINTER(siginfo_t), c_void_p)), ('sa_mask', c_uint), ('sa_flags', c_int), ]
class sigaction(Structure): _fields_ = [ ('__sigaction_u', sigaction_u),
('sa_mask', c_uint), ('sa_flags', c_int), ]
####################################### # END sigaction / siginfo structs
###################################### #call back that should be signalled,
void so return nothing def detailed_callback(signalno, siginfostruct, data):
print "detailed callback: ", signalno, \
siginfostruct, \
 data #ctypes prototype implementation C_PROTOTYPE_SIGNHANDLER =
CFUNCTYPE(None, c_int,
POINTER(__siginfo), c_void_p) #cast callback sighandler_cb =
C_PROTOTYPE_SIGNHANDLER(detailed_callback)
##################################### # globals/literals
##################################### ABS_PATH_LIBC =
util.find_library('libc') FCNTL_FLAGS=
[fcntl.DN_MODIFY,fcntl.DN_CREATE,fcntl.DN_DELETE,fcntl.DN_RENAME]
FCNTL_BIT_FLAG = reduce(lambda x, y: x | y, FCNTL_FLAGS) |
fcntl.DN_MULTISHOT #get library __clib = cdll.LoadLibrary(ABS_PATH_LIBC)
assert __clib is not None
#struct sigaction act; act = sigaction()

#act.sa_sigaction = handler;
act.__sigaction_u.sa_sigaction = sighandler_cb

#sigemptyset(&act.sa_mask);
#python2.6 has byref(act, offset),how can i port this over?
#maybe addressof(act)+sizeof(sigaction.sa_mask)*(position_in_sigaction)
rc = __clib.sigemptyset(byref(act))
assert rc == 0

#act.sa_flags = SA_SIGINFO;
#/usr/include/bit/signum.h SA_SIGINFO
#TODO: look this up from python act.sa_flags = 4;

#sigaction(SIGRTMIN, &act, NULL);
#signal.signal( signal.SIGRTMIN, sighandler_cb )
rc = __clib.sigaction( signal.SIGRTMIN, byref(act), None ) assert rc == 0

#fd stuff, open cwd, monitor for changes, should invoke
#my callback.. __fd = os.open(os.getcwd(), os.O_RDONLY | os.O_NONBLOCK)
__clib.fcntl( __fd, fcntl.F_SETSIG, signal.SIGRTMIN) __clib.fcntl( __fd,
fcntl.F_NOTIFY, FCNTL_BIT_FLAG ) import time while True: signal.pause()
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