From 8631708741447830311aeb210f6f02bb55a423f7 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sat, 28 Jul 2018 21:46:00 +0900
Subject: [PATCH] resolve: add option to toggle reading /etc/hosts

Workaround for #9718.
---
 man/resolved.conf.xml            | 7 +++++++
 src/resolve/resolved-etc-hosts.c | 3 +++
 src/resolve/resolved-gperf.gperf | 1 +
 src/resolve/resolved-manager.c   | 1 +
 src/resolve/resolved-manager.h   | 1 +
 src/resolve/resolved.conf.in     | 1 +
 6 files changed, 14 insertions(+)

diff --git a/man/resolved.conf.xml b/man/resolved.conf.xml
index dbd07e8151e..055c4745926 100644
--- a/man/resolved.conf.xml
+++ b/man/resolved.conf.xml
@@ -248,6 +248,13 @@
         in use.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>ReadEtcHosts=</varname></term>
+        <listitem><para>Takes a boolean argument. If <literal>yes</literal> (the default), the DNS stub resolver will read
+        <filename>/etc/hosts</filename>, and try to resolve hosts or address by using the entries in the file before
+        sending query to DNS servers.</para></listitem>
+      </varlistentry>
+
     </variablelist>
   </refsect1>
 
diff --git a/src/resolve/resolved-etc-hosts.c b/src/resolve/resolved-etc-hosts.c
index 2c52c91b72f..5d394a86393 100644
--- a/src/resolve/resolved-etc-hosts.c
+++ b/src/resolve/resolved-etc-hosts.c
@@ -324,6 +324,9 @@ int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer) {
         assert(q);
         assert(answer);
 
+        if (!m->read_etc_hosts)
+                return 0;
+
         r = manager_etc_hosts_read(m);
         if (r < 0)
                 return r;
diff --git a/src/resolve/resolved-gperf.gperf b/src/resolve/resolved-gperf.gperf
index 648ca4d8a24..9b9290b727e 100644
--- a/src/resolve/resolved-gperf.gperf
+++ b/src/resolve/resolved-gperf.gperf
@@ -26,3 +26,4 @@ Resolve.DNSSEC,          config_parse_dnssec_mode,            0,
 Resolve.DNSOverTLS,      config_parse_dns_over_tls_mode,      0,                   offsetof(Manager, dns_over_tls_mode)
 Resolve.Cache,           config_parse_bool,                   0,                   offsetof(Manager, enable_cache)
 Resolve.DNSStubListener, config_parse_dns_stub_listener_mode, 0,                   offsetof(Manager, dns_stub_listener_mode)
+Resolve.ReadEtcHosts,    config_parse_bool,                   0,                   offsetof(Manager, read_etc_hosts)
diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index 44a53952d24..03ca5188cb8 100644
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -581,6 +581,7 @@ int manager_new(Manager **ret) {
         m->read_resolv_conf = true;
         m->need_builtin_fallbacks = true;
         m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY;
+        m->read_etc_hosts = true;
 
         r = dns_trust_anchor_load(&m->trust_anchor);
         if (r < 0)
diff --git a/src/resolve/resolved-manager.h b/src/resolve/resolved-manager.h
index be7ad2d10dd..5251ca795de 100644
--- a/src/resolve/resolved-manager.h
+++ b/src/resolve/resolved-manager.h
@@ -117,6 +117,7 @@ struct Manager {
         Set* etc_hosts_by_address;
         Hashmap* etc_hosts_by_name;
         usec_t etc_hosts_last, etc_hosts_mtime;
+        bool read_etc_hosts;
 
         /* Local DNS stub on 127.0.0.53:53 */
         int dns_stub_udp_fd;
diff --git a/src/resolve/resolved.conf.in b/src/resolve/resolved.conf.in
index 2528340f74a..e559291f66c 100644
--- a/src/resolve/resolved.conf.in
+++ b/src/resolve/resolved.conf.in
@@ -21,3 +21,4 @@
 #DNSOverTLS=@DEFAULT_DNS_OVER_TLS_MODE@
 #Cache=yes
 #DNSStubListener=udp
+#ReadEtcHosts=yes
-- 
2.39.2