From 963c344ad49de6938a80f9c7acbc30d2b9a251f5 Mon Sep 17 00:00:00 2001
From: Nate Brown <nbrown.us@gmail.com>
Date: Mon, 7 Aug 2017 12:20:50 -0700
Subject: [PATCH] Slightly better netlink client tests

---
 audit.go       |  6 +++++-
 client.go      |  9 +++++----
 client_test.go | 23 ++++++++++++++---------
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/audit.go b/audit.go
index d5a7a77..9cc6cb0 100644
--- a/audit.go
+++ b/audit.go
@@ -342,7 +342,11 @@ func main() {
 		el.Fatal(err)
 	}
 
-	nlClient := NewNetlinkClient(config.GetInt("socket_buffer.receive"))
+	nlClient, err := NewNetlinkClient(config.GetInt("socket_buffer.receive"))
+	if err != nil {
+		el.Fatal(err)
+	}
+
 	marshaller := NewAuditMarshaller(
 		writer,
 		uint16(config.GetInt("events.min")),
diff --git a/client.go b/client.go
index 2859639..7538cb1 100644
--- a/client.go
+++ b/client.go
@@ -7,6 +7,7 @@ import (
 	"sync/atomic"
 	"syscall"
 	"time"
+	"fmt"
 )
 
 // Endianness is an alias for what we assume is the current machine endianness
@@ -42,10 +43,10 @@ type NetlinkClient struct {
 }
 
 // NewNetlinkClient creates a new NetLinkClient and optionally tries to modify the netlink recv buffer
-func NewNetlinkClient(recvSize int) *NetlinkClient {
+func NewNetlinkClient(recvSize int) (*NetlinkClient, error) {
 	fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_AUDIT)
 	if err != nil {
-		el.Fatalln("Could not create a socket:", err)
+		return nil, fmt.Errorf("Could not create a socket: %s", err)
 	}
 
 	n := &NetlinkClient{
@@ -56,7 +57,7 @@ func NewNetlinkClient(recvSize int) *NetlinkClient {
 
 	if err = syscall.Bind(fd, n.address); err != nil {
 		syscall.Close(fd)
-		el.Fatalln("Could not bind to netlink socket:", err)
+		return nil, fmt.Errorf("Could not bind to netlink socket: %s", err)
 	}
 
 	// Set the buffer size if we were asked
@@ -78,7 +79,7 @@ func NewNetlinkClient(recvSize int) *NetlinkClient {
 		}
 	}()
 
-	return n
+	return n, nil
 }
 
 // Send will send a packet and payload to the netlink socket without waiting for a response
diff --git a/client_test.go b/client_test.go
index bc79df1..440fd23 100644
--- a/client_test.go
+++ b/client_test.go
@@ -91,15 +91,20 @@ func TestNewNetlinkClient(t *testing.T) {
 	lb, elb := hookLogger()
 	defer resetLogger()
 
-	n := NewNetlinkClient(1024)
-
-	assert.True(t, (n.fd > 0), "No file descriptor")
-	assert.True(t, (n.address != nil), "Address was nil")
-	assert.Equal(t, uint32(0), n.seq, "Seq should start at 0")
-	assert.True(t, MAX_AUDIT_MESSAGE_LENGTH >= len(n.buf), "Client buffer is too small")
-
-	assert.Equal(t, "Socket receive buffer size: ", lb.String()[:28], "Expected some nice log lines")
-	assert.Equal(t, "", elb.String(), "Did not expect any error messages")
+	n, err := NewNetlinkClient(1024)
+
+	assert.Nil(t, err)
+	if n == nil {
+		t.Fatal("Expected a netlink client but had an error instead!")
+	} else {
+		assert.True(t, (n.fd > 0), "No file descriptor")
+		assert.True(t, (n.address != nil), "Address was nil")
+		assert.Equal(t, uint32(0), n.seq, "Seq should start at 0")
+		assert.True(t, MAX_AUDIT_MESSAGE_LENGTH >= len(n.buf), "Client buffer is too small")
+
+		assert.Equal(t, "Socket receive buffer size: ", lb.String()[:28], "Expected some nice log lines")
+		assert.Equal(t, "", elb.String(), "Did not expect any error messages")
+	}
 }
 
 // Helper to make a client listening on a unix socket