net: extend the workaround to DialTCP to try to get arm building again.

Awfulness by the bucket that we hope
Fixes #3057.

R=golang-dev, mikioh.mikioh, dsymonds, r, rsc
CC=golang-dev
https://golang.org/cl/5687060

diff --git a/src/pkg/net/ipsock_posix.go b/src/pkg/net/ipsock_posix.go
index 8754451b33e4713c226a11e28e602ee263e15f54..4da18a5061ac3d3d156bd408a3cfef9fa12fd65a 100644 (file)
--- a/src/pkg/net/ipsock_posix.go
+++ b/src/pkg/net/ipsock_posix.go
@@ -117,10 +117,6 @@ func internetSocket(net string, laddr, raddr sockaddr, sotype, proto int, mode s
                if ra, oserr = raddr.sockaddr(family); oserr != nil {
                        goto Error
                }
-               if ra == nil {
-                       // TODO(r): part of selfConnect debugging
-                       panic("ra nil when raddr non-nil")
-               }
        }
        fd, oserr = socket(net, family, sotype, proto, la, ra, toAddr)
        if oserr != nil {

diff --git a/src/pkg/net/tcpsock_posix.go b/src/pkg/net/tcpsock_posix.go
index 1280f7bb08b9338a45faa91cebc23d6fa0c49141..e05bc10170e711d39b416733198c3c4222314355 100644 (file)
--- a/src/pkg/net/tcpsock_posix.go
+++ b/src/pkg/net/tcpsock_posix.go
@@ -29,8 +29,7 @@ func sockaddrToTCP(sa syscall.Sockaddr) Addr {
                return &TCPAddr{sa.Addr[0:], sa.Port}
        default:
                if sa != nil {
-                       // TODO(r): Diagnose when we will turn a non-nil sockaddr into a nil.
-                       // Part of diagnosing the selfConnect bug.
+                       // Diagnose when we will turn a non-nil sockaddr into a nil.
                        panic(fmt.Sprintf("unexpected type in sockaddrToTCP: %T", sa))
                }
        }
@@ -237,13 +236,6 @@ func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
 
        fd, err := internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_STREAM, 0, "dial", sockaddrToTCP)
 
-       checkRaddr := func(s string) {
-               if err == nil && fd.raddr == nil {
-                       panic("nil raddr in DialTCP: " + s)
-               }
-       }
-       checkRaddr("early")
-
        // TCP has a rarely used mechanism called a 'simultaneous connection' in
        // which Dial("tcp", addr1, addr2) run on the machine at addr1 can
        // connect to a simultaneous Dial("tcp", addr2, addr1) run on the machine
@@ -264,7 +256,6 @@ func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
        for i := 0; i < 2 && err == nil && laddr == nil && selfConnect(fd); i++ {
                fd.Close()
                fd, err = internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_STREAM, 0, "dial", sockaddrToTCP)
-               checkRaddr("after close")
        }
 
        if err != nil {
@@ -274,6 +265,17 @@ func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
 }
 
 func selfConnect(fd *netFD) bool {
+       // The socket constructor can return an fd with raddr nil under certain
+       // unknown conditions. The errors in the calls there to Getpeername
+       // are discarded, but we can't catch the problem there because those
+       // calls are sometimes legally erroneous with a "socket not connected".
+       // Since this code (selfConnect) is already trying to work around
+       // a problem, we make sure if this happens we recognize trouble and
+       // ask the DialTCP routine to try again.
+       // TODO: try to understand what's really going on.
+       if fd.laddr == nil || fd.raddr == nil {
+               return true
+       }
        l := fd.laddr.(*TCPAddr)
        r := fd.raddr.(*TCPAddr)
        return l.Port == r.Port && l.IP.Equal(r.IP)