Allow building on !linux

PiperOrigin-RevId: 209819644
Change-Id: I329d054bf8f4999e7db0dcd95b13f7793c65d4e2

pkg/rand/BUILD

@@ -4,7 +4,10 @@ load("//tools/go_stateify:defs.bzl", "go_library")
 
 go_library(
     name = "rand",
-    srcs = ["rand.go"],
+    srcs = [
+        "rand.go",
+        "rand_linux.go",
+    ],
     importpath = "gvisor.googlesource.com/gvisor/pkg/rand",
     visibility = ["//:sandbox"],
     deps = ["@org_golang_x_sys//unix:go_default_library"],

pkg/rand/rand.go

@@ -12,28 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !linux
+
 // Package rand implements a cryptographically secure pseudorandom number
 // generator.
 package rand
 
-import (
-	"io"
-
-	"golang.org/x/sys/unix"
-)
-
-// reader implements an io.Reader that returns pseudorandom bytes.
-type reader struct{}
-
-// Read implements io.Reader.Read.
-func (reader) Read(p []byte) (int, error) {
-	return unix.Getrandom(p, 0)
-}
+import "crypto/rand"
 
 // Reader is the default reader.
-var Reader io.Reader = reader{}
+var Reader = rand.Reader
 
-// Read reads from the default reader.
+// Read implements io.Reader.Read.
 func Read(b []byte) (int, error) {
-	return io.ReadFull(Reader, b)
+	return rand.Read(b)
 }

pkg/rand/rand_linux.go

@@ -0,0 +1,39 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package rand implements a cryptographically secure pseudorandom number
+// generator.
+package rand
+
+import (
+	"io"
+
+	"golang.org/x/sys/unix"
+)
+
+// reader implements an io.Reader that returns pseudorandom bytes.
+type reader struct{}
+
+// Read implements io.Reader.Read.
+func (reader) Read(p []byte) (int, error) {
+	return unix.Getrandom(p, 0)
+}
+
+// Reader is the default reader.
+var Reader io.Reader = reader{}
+
+// Read reads from the default reader.
+func Read(b []byte) (int, error) {
+	return io.ReadFull(Reader, b)
+}

pkg/tcpip/link/fdbased/endpoint.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 // Package fdbased provides the implemention of data-link layer endpoints
 // backed by boundary-preserving file descriptors (e.g., TUN devices,
 // seqpacket/datagram sockets).

pkg/tcpip/link/fdbased/endpoint_test.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package fdbased
 
 import (

pkg/tcpip/link/sharedmem/rx.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package sharedmem
 
 import (

pkg/tcpip/link/sharedmem/sharedmem.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 // Package sharedmem provides the implemention of data-link layer endpoints
 // backed by shared memory.
 //

pkg/tcpip/link/sharedmem/sharedmem_test.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package sharedmem
 
 import (

pkg/tcpip/link/tun/tun_unsafe.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 // Package tun contains methods to open TAP and TUN devices.
 package tun
 

pkg/tcpip/sample/tun_tcp_connect/main.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 // This sample creates a stack with TCP and IPv4 protocols on top of a TUN
 // device, and connects to a peer. Similar to "nc <address> <port>". While the
 // sample is running, attempts to connect to its IPv4 address will result in

pkg/tcpip/sample/tun_tcp_echo/main.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 // This sample creates a stack with TCP and IPv4 protocols on top of a TUN
 // device, and listens on a port. Data received by the server in the accepted
 // connections is echoed back to the clients.