On Thu, Sep 05, 2013 at 03:48:16PM +0200, Sebastian Ottlik wrote: > On 04.09.2013 19:08, Sebastian Ottlik wrote: > >This patchset disabels all use of SO_REUSEADDR on Windows. On Windows systems > >the default behaviour is equivalent to SO_REUSEADDR on other operating > >systems. SO_REUSEADDR can still be set but results in undesired behaviour > >instead. It may even lead to situations were system behaviour is > >unspecified. More information on this can be found at: > >http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx > > > >I originally encountered this issue when accidentally launching two QEMU > >instances with identical GDB ports at the same time. In which case QEMU won't > >fail as one might expect. > > > >v2 Changes: > > > >- Introduce a function with os specific implementation instead of using > >#ifdef > > I named it socket_set_fast_reuse instead of the suggested > > qemu_set_reuseaddr > > so the name better reflects what the function actually does. > > > > gdbstub.c | 6 ++---- > > include/qemu/sockets.h | 1 + > > net/socket.c | 19 +++++++------------ > > slirp/misc.c | 3 +-- > > slirp/socket.c | 4 +--- > > slirp/tcp_subr.c | 6 ++---- > > slirp/udp.c | 4 ++-- > > util/oslib-posix.c | 14 ++++++++++++++ > > util/oslib-win32.c | 10 ++++++++++ > > util/qemu-sockets.c | 6 +++--- > > 10 files changed, 43 insertions(+), 30 deletions(-) > > > > > >util: add socket_set_fast_reuse function > >gdbstub: call socket_set_fast_reuse instead of setting SO_REUSEADDR > >net: call socket_set_fast_reuse instead of setting SO_REUSEADDR > >slirp: call socket_set_fast_reuse instead of setting SO_REUSEADDR > >util: call socket_set_fast_reuse instead of setting SO_REUSEADDR > > > > Pinging this patch, as I think it is still an appropriate approach > to the issue: > > I did some research and apparently there is a valid use case for > SO_REUSEADDR > on windows when multiple clients need to listen to the same port for > the same > multicast group. IMHO making qemu_setsockopt ignore SO_REUSEADDR on windows > might be confusing for some use cases. Actually net_socket_mcast_create in > net/socket.c should probably set SO_REUSEADDR on windows. This is > also an issue > with patch 3 I supplied that I will address in a new version of this > patch set if there is > an agreement on a general approach.
Sounds like a good idea. The patch series overall looks good. Stefan
