syscall, net: Fix unix socket autobind on Linux.

R=rsc, iant, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/7300047

diff --git a/src/pkg/net/unix_test.go b/src/pkg/net/unix_test.go
index 7ea332041765667d97e0679e0392d98f54244263..dda717ea9388fbfd744858020e4bbab74db57dbd 100644 (file)
--- a/src/pkg/net/unix_test.go
+++ b/src/pkg/net/unix_test.go
@@ -10,6 +10,8 @@ import (
        "bytes"
        "io/ioutil"
        "os"
+       "reflect"
+       "runtime"
        "syscall"
        "testing"
        "time"
@@ -121,3 +123,35 @@ func TestReadUnixgramWithZeroBytesBuffer(t *testing.T) {
                t.Errorf("peer adddress is %v", peer)
        }
 }
+
+func TestUnixAutobind(t *testing.T) {
+       if runtime.GOOS != "linux" {
+               t.Skip("skipping: autobind is linux only")
+       }
+
+       laddr := &UnixAddr{Name: "", Net: "unixgram"}
+       c1, err := ListenUnixgram("unixgram", laddr)
+       if err != nil {
+               t.Fatalf("ListenUnixgram failed: %v", err)
+       }
+       defer c1.Close()
+
+       // retrieve the autobind address
+       autoAddr := c1.LocalAddr().(*UnixAddr)
+       if len(autoAddr.Name) <= 1 {
+               t.Fatalf("Invalid autobind address: %v", autoAddr)
+       }
+       if autoAddr.Name[0] != '@' {
+               t.Fatalf("Invalid autobind address: %v", autoAddr)
+       }
+
+       c2, err := DialUnix("unixgram", nil, autoAddr)
+       if err != nil {
+               t.Fatalf("DialUnix failed: %v", err)
+       }
+       defer c2.Close()
+
+       if !reflect.DeepEqual(c1.LocalAddr(), c2.RemoteAddr()) {
+               t.Fatalf("Expected autobind address %v, got %v", c1.LocalAddr(), c2.RemoteAddr())
+       }
+}

diff --git a/src/pkg/syscall/syscall_linux.go b/src/pkg/syscall/syscall_linux.go
index 038eb4a01741f65792b3412df24901d5a7a8ab78..689511426aabe91bb639ed23985fc29047b1ef48 100644 (file)
--- a/src/pkg/syscall/syscall_linux.go
+++ b/src/pkg/syscall/syscall_linux.go
@@ -279,7 +279,7 @@ type SockaddrUnix struct {
 func (sa *SockaddrUnix) sockaddr() (uintptr, _Socklen, error) {
        name := sa.Name
        n := len(name)
-       if n >= len(sa.raw.Path) || n == 0 {
+       if n >= len(sa.raw.Path) {
                return 0, 0, EINVAL
        }
        sa.raw.Family = AF_UNIX
@@ -287,7 +287,10 @@ func (sa *SockaddrUnix) sockaddr() (uintptr, _Socklen, error) {
                sa.raw.Path[i] = int8(name[i])
        }
        // length is family (uint16), name, NUL.
-       sl := 2 + _Socklen(n) + 1
+       sl := _Socklen(2)
+       if n > 0 {
+               sl += _Socklen(n) + 1
+       }
        if sa.raw.Path[0] == '@' {
                sa.raw.Path[0] = 0
                // Don't count trailing NUL for abstract address.