Mail Archives: cygwin-developers/1998/06/14/10:46:43
>From: Sergey Okhapkin <sos AT prospect DOT com DOT ru>
>Date: Sun, 14 Jun 1998 09:27:19 +0400
>
>Tim Newsham wrote:
>> I have put block_sig_dispatch()/allow_sig_dispatch() around a
>> few calls in net.cc to protect them from signals (when signals come
>> in during certain calls, my socket handles seem to get messed up).
>> Now I'm seeing some signal weirdness. It seems to properly handle
>> receiving most signals; it just defers the signal until the allow
>> call gets called. But, when I send a SIGKILL, the program dumps
>> core when the allow_sig_dispatch() call is finally made. I can
>
>> (c:\home\test\tests\a.exe 1069) <1> __cygwin32_exception_handler: In
>cygwin32_except_handler exc C0000005 at 74FF21FA sp 244F760
>> (c:\home\test\tests\a.exe 1069) <0> __cygwin32_exception_handler: In
>cygwin32_except_handler sig = 11 at 74FF21FA
>
>I don't know if there are some relations, but the trap address is well
>known for me :-)
>When cygwin application while in a blocking winsock call receives any
>signal whose disposition is to terminate a process, the application traps
>in a system dll when calling WSACleanup() (exception.cc, routine
>sig_handle, label exit_sig). Try to remove this call and see what will
>happen. But it will be impossible to kill cygwin application untill a
>blocking winsock call terminates:-(
>
>What are the reasons to call do_exit() in a context of main thread? Why not
>suspend main thread and to call do_exit in the context of signal processing
>thread (with the call to WSACleanup() removed)?
From your description of the problem, I'm not sure what that would solve.
Isn't the key thing to just ensure that WSACleanup is not called? Sure,
you could call do_exit in the context of the signal thread for the specific
case of SIGKILL but what happens if there is a signal handler which calls
exit() when something like a SIGTERM is received? From your description,
there will be a hang.
--
cgf AT cygnus DOT com "Everything has a boolean value, if you stand
http://www.cygnus.com/ far enough away from it." -- Galena Alyson Canada
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