On 11/11/2013 10:13 AM, Peter Maydell wrote: > On 11 November 2013 17:05, Paolo Bonzini <pbonz...@redhat.com> wrote: >> That said, aren't all signals in QEMU (except SIG_IPI) caught with >> signalfd and the handlers run synchronously in the iothread? > > Eric specifically points out one which is not. > (I'm pretty sure that 'reinstall signal handler at > end of signal handler' is ancient voodoo that we don't > want either, incidentally.)
Reinstalling the signal handler is voodoo needed only for systems where SA_RESETHAND is the default behavior of signal() (POSIX says that the older signal() is implementation-defined whether it behaves like SA_RESETHAND|SA_NODEFER [SysV] or SA_RESTART [BSD] - so it is already mandatory to use sigaction() if you don't want to be bitten by the difference in semantics; but if you can assume working sigaction(), then don't use signal() or SA_RESETHAND in the first place, and you don't need the reinstall voodoo in your handlers). -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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