2011/4/7 Marcin Konarski: > On Wed, Mar 30, 2011 at 01:52:05PM +0200, Marcin Konarski wrote: >> Hello list. >> >> I have a code that depends on calls that are normally interruptible >> by signals to be interrupted by signal delivery also in threads. >> >> In my installation of cygwin I see that calls are interrupted >> as long as I do not try to run them inside a thread. > > Nobody answered so I bothered to get cygwin sources > and look through relevant code parts. > > I started with stracing both scenarios: > 1) interruptible_call() without threads > 2) interruptible_call() in thread > > (again, the issue I reported is that in case 2 > signals do not interrupt interruptible_call()) > > I sample program I have posted the call in question was select(), > so I started my investigation with that. > > select() as in winsup/cygwin/select.cc: > extern "C" int > cygwin_select (int maxfds, fd_set *readfds, fd_set *writefds, fd_set > *exceptfds, struct timeval *to); > > uses signal_arrived Windows Event object as a means for interruption. > > This event is fired from: > > winsup/cygwin/exceptions.cc: > void __stdcall _cygtls::interrupt_setup (int sig, void *handler, struct > sigaction& siga); > static int setup_handler (int sig, void *handler, struct sigaction& siga, > _cygtls *tls); > int __stdcall sigpacket::process (); > > During strace sessions I see (among others): > > for case 1: > 60 2755927 [sig] 1exec 3260 _cygtls::find_tls: sig 14 > 41 2755968 [sig] 1exec 3260 sigpacket::process: signal 14, about to call > 0x66CDF0A8 > 38 2756006 [sig] 1exec 3260 setup_handler: controlled interrupt. stackptr > 0x28DB34, stack 0x28DB30, stackptr[-1] 0x66CE7F39 > > for case 2: > 59 2759537 [sig] 1exec 2920 _cygtls::find_tls: sig 14 > 24 2759561 [sig] 1exec 2920 sigpacket::process: signal 14 blocked > 24 2759585 [sig] 1exec 2920 sigpacket::process: returning -1 > > The difference from those outputs results from the fact that > _cygtls * _cygtls::find_tls (int sig); > ffrom: winsup/cygwin/cygtls.cc > > does not find given signal > in sigwait_mask field of any _cygtls object of any thread. > > I see in: > winsup/cygwin/thread.cc, and winsup/cygwin/signal.cc, > that neither: > extern "C" int pthread_sigmask (int operation, const sigset_t *set, sigset_t > *old_set); > nor > extern "C" int sigprocmask (int how, const sigset_t *set, sigset_t *oldset); > changes the sigwait_mask field of _cygtls, > only sigmask field of _cygtls is modified. > > Does anybody have an idea if changing > _cygtls * _cygtls::find_tls (int sig); > in such a way that it would look through both sigwait_mask and sigmask > fields would solve the issue raised?
I don't know, and the core Cygwin developers appear to be away or too busy. Have you tried it? Andy -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
