From 3a4322627e781c05418a8cc40ebb9f547a6c4ac8 Mon Sep 17 00:00:00 2001 From: Fazlul Shahriar Date: Wed, 8 Jul 2020 16:57:10 -0400 Subject: [PATCH] net: hangup TCP connection after Dial timeout in Plan 9 After Dial timeout, force close the TCP connection by writing "hangup" to the control file. This unblocks the "connect" command if the connection is taking too long to establish, and frees up the control file FD. Fixes #40118 Change-Id: I1cef8539cd9fe0793e32b49c9d0ef636b4b26e1d Reviewed-on: https://go-review.googlesource.com/c/go/+/241638 Run-TryBot: David du Colombier <0intro@gmail.com> TryBot-Result: Gobot Gobot Reviewed-by: David du Colombier <0intro@gmail.com> --- src/net/ipsock_plan9.go | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/src/net/ipsock_plan9.go b/src/net/ipsock_plan9.go index 99d3e3971a..23082366aa 100644 --- a/src/net/ipsock_plan9.go +++ b/src/net/ipsock_plan9.go @@ -206,9 +206,9 @@ func dialPlan9Blocking(ctx context.Context, net string, laddr, raddr Addr) (fd * return nil, err } if la := plan9LocalAddr(laddr); la == "" { - _, err = f.WriteString("connect " + dest) + err = hangupCtlWrite(ctx, proto, f, "connect "+dest) } else { - _, err = f.WriteString("connect " + dest + " " + la) + err = hangupCtlWrite(ctx, proto, f, "connect "+dest+" "+la) } if err != nil { f.Close() @@ -339,3 +339,27 @@ func plan9LocalAddr(addr Addr) string { } return ip.String() + "!" + itoa(port) } + +func hangupCtlWrite(ctx context.Context, proto string, ctl *os.File, msg string) error { + if proto != "tcp" { + _, err := ctl.WriteString(msg) + return err + } + written := make(chan struct{}) + errc := make(chan error) + go func() { + select { + case <-ctx.Done(): + ctl.WriteString("hangup") + errc <- mapErr(ctx.Err()) + case <-written: + errc <- nil + } + }() + _, err := ctl.WriteString(msg) + close(written) + if e := <-errc; err == nil && e != nil { // we hung up + return e + } + return err +} -- 2.50.0