- clients: fix incorrect info for clients from /etc/hosts

Close #1786

Squashed commit of the following:

commit fc662252be38f20c9afda46fcb578efa50c9baf2
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Jun 11 10:57:26 2020 +0300

    - clients: fix incorrect info for clients from /etc/hosts

home/clients.go

@@ -612,15 +612,13 @@ func (clients *clientsContainer) addFromHostsFile() {
 	_ = clients.rmHosts(ClientSourceHostsFile)
 
 	n := 0
-	for ip, names := range hosts {
-		for _, name := range names {
-			ok, err := clients.addHost(ip, name.String(), ClientSourceHostsFile)
-			if err != nil {
-				log.Debug("Clients: %s", err)
-			}
-			if ok {
-				n++
-			}
+	for ip, name := range hosts {
+		ok, err := clients.addHost(ip, name, ClientSourceHostsFile)
+		if err != nil {
+			log.Debug("Clients: %s", err)
+		}
+		if ok {
+			n++
 		}
 	}
 

util/auto_hosts.go

@@ -371,11 +371,11 @@ func (a *AutoHosts) ProcessReverse(addr string, qtype uint16) string {
 	return host
 }
 
-// List - get the hosts table.  Thread-safe.
-func (a *AutoHosts) List() map[string][]net.IP {
-	table := make(map[string][]net.IP)
+// List - get "IP -> hostname" table.  Thread-safe.
+func (a *AutoHosts) List() map[string]string {
+	table := make(map[string]string)
 	a.lock.Lock()
-	for k, v := range a.table {
+	for k, v := range a.tableReverse {
 		table[k] = v
 	}
 	a.lock.Unlock()

util/auto_hosts_test.go

@@ -49,10 +49,9 @@ func TestAutoHostsResolution(t *testing.T) {
 
 	// Test hosts file
 	table := ah.List()
-	ips, _ = table["host"]
-	assert.NotNil(t, ips)
-	assert.Equal(t, 1, len(ips))
-	assert.Equal(t, "127.0.0.1", ips[0].String())
+	name, ok := table["127.0.0.1"]
+	assert.True(t, ok)
+	assert.Equal(t, "host", name)
 
 	// Test PTR
 	a, _ := dns.ReverseAddr("127.0.0.1")