Excerpts from Jun Wu's message of 2017-01-30 16:52:46 +0000: > # HG changeset patch > # User Jun Wu <qu...@fb.com> > # Date 1485794838 0 > # Mon Jan 30 16:47:18 2017 +0000 > # Node ID 0f9c5c49ad7ac321f6fecb4ca90121969bb038d4 > # Parent ea5353feeec3c2eddd7e4acfd398baddaf37b3e4 > # Available At https://bitbucket.org/quark-zju/hg-draft > # hg pull https://bitbucket.org/quark-zju/hg-draft -r > 0f9c5c49ad7a > commandserver: handle backlog before exiting > > Previously, when a chg server is exiting, it does not handle connected > clients so clients may get ECONNRESET and crash: > > 1. client connect() # success > 2. server shouldexit = True and exit > 3. client recv() # ECONNRESET > > d7875bfbfccb makes this race condition easier to reproduce if a lot of short > chg commands are started in parallel. > > This patch fixes the above issue by unlinking the socket path to prevent new > connections and handling all pending connections before exiting. > > diff --git a/mercurial/commandserver.py b/mercurial/commandserver.py > --- a/mercurial/commandserver.py > +++ b/mercurial/commandserver.py > @@ -412,5 +412,9 @@ class unixservicehandler(object): > > def unlinksocket(self, address): > - os.unlink(address) > + try: > + os.unlink(address) > + except OSError as ex: > + if ex.errno != errno.ENOENT: > + raise
This introduces another race condition that unlinks an innocent socket file. I will send a V2 later. > > def printbanner(self, address): > @@ -471,9 +475,17 @@ class unixforkingservice(object): > > def _mainloop(self): > + exiting = False > h = self._servicehandler > - while not h.shouldexit(): > + while True: > + if not exiting and h.shouldexit(): > + # prevent accepting new connections > + self._servicehandler.unlinksocket(self.address) > + exiting = True > try: > ready = select.select([self._sock], [], [], > h.pollinterval)[0] > if not ready: > + # only exit if we have no more connections to handle > + if exiting: > + break > continue > conn, _addr = self._sock.accept() _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
