net: enforce timeouts for ReadFrom/WriteTo

Fixes #153.

R=r
https://golang.org/cl/154177

src/pkg/net/fd.go

@@ -372,6 +372,33 @@ func (fd *netFD) Read(p []byte) (n int, err os.Error) {
 	return;
 }
 
+func (fd *netFD) ReadFrom(p []byte) (n int, sa syscall.Sockaddr, err os.Error) {
+	if fd == nil || fd.file == nil {
+		return 0, nil, os.EINVAL
+	}
+	fd.rio.Lock();
+	defer fd.rio.Unlock();
+	if fd.rdeadline_delta > 0 {
+		fd.rdeadline = pollserver.Now() + fd.rdeadline_delta
+	} else {
+		fd.rdeadline = 0
+	}
+	for {
+		var errno int;
+		n, sa, errno = syscall.Recvfrom(fd.fd, p, 0);
+		if errno == syscall.EAGAIN && fd.rdeadline >= 0 {
+			pollserver.WaitRead(fd);
+			continue;
+		}
+		if errno != 0 {
+			n = 0;
+			err = &os.PathError{"recvfrom", fd.file.Name(), os.Errno(errno)};
+		}
+		break;
+	}
+	return;
+}
+
 func (fd *netFD) Write(p []byte) (n int, err os.Error) {
 	if fd == nil || fd.file == nil {
 		return 0, os.EINVAL
@@ -404,6 +431,35 @@ func (fd *netFD) Write(p []byte) (n int, err os.Error) {
 	return nn, err;
 }
 
+func (fd *netFD) WriteTo(p []byte, sa syscall.Sockaddr) (n int, err os.Error) {
+	if fd == nil || fd.file == nil {
+		return 0, os.EINVAL
+	}
+	fd.wio.Lock();
+	defer fd.wio.Unlock();
+	if fd.wdeadline_delta > 0 {
+		fd.wdeadline = pollserver.Now() + fd.wdeadline_delta
+	} else {
+		fd.wdeadline = 0
+	}
+	err = nil;
+	for {
+		errno := syscall.Sendto(fd.fd, p, 0, sa);
+		if errno == syscall.EAGAIN && fd.wdeadline >= 0 {
+			pollserver.WaitWrite(fd);
+			continue;
+		}
+		if errno != 0 {
+			err = &os.PathError{"sendto", fd.file.Name(), os.Errno(errno)}
+		}
+		break;
+	}
+	if err == nil {
+		n = len(p)
+	}
+	return;
+}
+
 func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (nfd *netFD, err os.Error) {
 	if fd == nil || fd.file == nil {
 		return nil, os.EINVAL

src/pkg/net/server_test.go

@@ -116,7 +116,7 @@ func runPacket(t *testing.T, network, addr string, listening chan<- string, done
 	var buf [1000]byte;
 	for {
 		n, addr, err := c.ReadFrom(&buf);
-		if err == os.EAGAIN {
+		if isEAGAIN(err) {
 			if done <- 1 {
 				break
 			}

src/pkg/net/timeout_test.go

@@ -5,11 +5,12 @@
 package net
 
 import (
+	"os";
 	"testing";
 	"time";
 )
 
-func testTimeout(t *testing.T, network, addr string) {
+func testTimeout(t *testing.T, network, addr string, readFrom bool) {
 	fd, err := Dial(network, "", addr);
 	defer fd.Close();
 	if err != nil {
@@ -18,21 +19,34 @@ func testTimeout(t *testing.T, network, addr string) {
 	t0 := time.Nanoseconds();
 	fd.SetReadTimeout(1e8);	// 100ms
 	var b [100]byte;
-	n, err1 := fd.Read(&b);
+	var n int;
+	var err1 os.Error;
+	if readFrom {
+		n, _, err1 = fd.(PacketConn).ReadFrom(&b)
+	} else {
+		n, err1 = fd.Read(&b)
+	}
 	t1 := time.Nanoseconds();
+	what := "Read";
+	if readFrom {
+		what = "ReadFrom"
+	}
 	if n != 0 || !isEAGAIN(err1) {
-		t.Errorf("fd.Read on %s %s did not return 0, EAGAIN: %v, %v", network, addr, n, err1)
+		t.Errorf("fd.%s on %s %s did not return 0, EAGAIN: %v, %v", what, network, addr, n, err1)
 	}
 	if t1-t0 < 0.5e8 || t1-t0 > 1.5e8 {
-		t.Errorf("fd.Read on %s %s took %f seconds, expected 0.1", network, addr, float64(t1-t0)/1e9)
+		t.Errorf("fd.%s on %s %s took %f seconds, expected 0.1", what, network, addr, float64(t1-t0)/1e9)
 	}
 }
 
-func TestTimeoutUDP(t *testing.T)	{ testTimeout(t, "udp", "127.0.0.1:53") }
+func TestTimeoutUDP(t *testing.T) {
+	testTimeout(t, "udp", "127.0.0.1:53", false);
+	testTimeout(t, "udp", "127.0.0.1:53", true);
+}
 
 func TestTimeoutTCP(t *testing.T) {
 	// 74.125.19.99 is www.google.com.
 	// could use dns, but dns depends on
 	// timeouts and this is the timeout test.
-	testTimeout(t, "tcp", "74.125.19.99:80")
+	testTimeout(t, "tcp", "74.125.19.99:80", false)
 }

src/pkg/net/udpsock.go

@@ -188,10 +188,7 @@ func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err os.Error) {
 	if !c.ok() {
 		return 0, nil, os.EINVAL
 	}
-	n, sa, errno := syscall.Recvfrom(c.fd.fd, b, 0);
-	if errno != 0 {
-		err = os.Errno(errno)
-	}
+	n, sa, err := c.fd.ReadFrom(b);
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
 		addr = &UDPAddr{&sa.Addr, sa.Port}
@@ -228,10 +225,7 @@ func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (n int, err os.Error) {
 	if err != nil {
 		return 0, err
 	}
-	if errno := syscall.Sendto(c.fd.fd, b, 0, sa); errno != 0 {
-		return 0, os.Errno(errno)
-	}
-	return len(b), nil;
+	return c.fd.WriteTo(b, sa);
 }
 
 // WriteTo writes a UDP packet with payload b to addr via c.

src/pkg/net/unixsock.go

@@ -243,10 +243,7 @@ func (c *UnixConn) ReadFromUnix(b []byte) (n int, addr *UnixAddr, err os.Error)
 	if !c.ok() {
 		return 0, nil, os.EINVAL
 	}
-	n, sa, errno := syscall.Recvfrom(c.fd.fd, b, 0);
-	if errno != 0 {
-		err = os.Errno(errno)
-	}
+	n, sa, err := c.fd.ReadFrom(b);
 	switch sa := sa.(type) {
 	case *syscall.SockaddrUnix:
 		addr = &UnixAddr{sa.Name, c.fd.proto == syscall.SOCK_DGRAM}
@@ -281,10 +278,7 @@ func (c *UnixConn) WriteToUnix(b []byte, addr *UnixAddr) (n int, err os.Error) {
 		return 0, os.EAFNOSUPPORT
 	}
 	sa := &syscall.SockaddrUnix{Name: addr.Name};
-	if errno := syscall.Sendto(c.fd.fd, b, 0, sa); errno != 0 {
-		return 0, os.Errno(errno)
-	}
-	return len(b), nil;
+	return c.fd.WriteTo(b, sa);
 }
 
 // WriteTo writes a packet to addr via c, copying the payload from b.