Rebuild server array after each change

On /etc/resolv.conf of d-bus update of servers, dnsmasq did not update
dnsmasq_daemon->serverarray properly. Call refresh after each change.

When resolv.conf resolvers are cleared, dnsmasq_daemon->serverarray
were not properly refreshed. Force refresh as part of removal.

Replaces original upstream commit, which fixed only some use-cases:
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=d290630d31f4517ab26392d00753d1397f9a4114

Resolves: rhbz#2009975
Related: rhbz#2014019

dnsmasq-2.86-build_server_array.patch

@@ -0,0 +1,67 @@
+From 068e849c713fa5e95eeb210792c061b7e212eab5 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
+Date: Wed, 13 Oct 2021 16:58:39 +0200
+Subject: [PATCH] Ensure serverarray is rebuilt once server can be removed
+
+Because cleanup_servers is called from each place which can remove
+server, use that function to refresh serverarray after changes. Make it
+static, since it does not have to be called from other places.
+---
+ src/dnsmasq.h      | 1 -
+ src/domain-match.c | 8 +++++++-
+ src/network.c      | 1 -
+ 3 files changed, 7 insertions(+), 3 deletions(-)
+
+diff --git a/src/dnsmasq.h b/src/dnsmasq.h
+index 08f2785..3f82412 100644
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -1757,7 +1757,6 @@ void dump_packet(int mask, void *packet, size_t len, union mysockaddr *src, unio
+ #endif
+ 
+ /* domain-match.c */
+-void build_server_array(void);
+ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout);
+ int filter_servers(int seed, int flags, int *lowout, int *highout);
+ int is_local_answer(time_t now, int first, char *name);
+diff --git a/src/domain-match.c b/src/domain-match.c
+index 45528c1..e5b409e 100644
+--- a/src/domain-match.c
++++ b/src/domain-match.c
+@@ -23,7 +23,7 @@ static int order_servers(struct server *s, struct server *s2);
+ /* If the server is USE_RESOLV or LITERAL_ADDRES, it lives on the local_domains chain. */
+ #define SERV_IS_LOCAL (SERV_USE_RESOLV | SERV_LITERAL_ADDRESS)
+ 
+-void build_server_array(void)
++static void build_server_array(void)
+ {
+   struct server *serv;
+   int count = 0;
+@@ -592,6 +592,12 @@ void cleanup_servers(void)
+       else 
+ 	up = &serv->next;
+    }
++
++  /* If we're delaying things, we don't call check_servers(), but
++     reload_servers() may have deleted some servers, rendering the server_array
++     invalid, so just rebuild that here. Once reload_servers() succeeds,
++     we call check_servers() above, which calls build_server_array itself. */
++  build_server_array();
+ }
+ 
+ int add_update_server(int flags,
+diff --git a/src/network.c b/src/network.c
+index 3fc179d..0b68866 100644
+--- a/src/network.c
++++ b/src/network.c
+@@ -1653,7 +1653,6 @@ void check_servers(int no_loop_check)
+     }
+   
+   cleanup_servers(); /* remove servers we just deleted. */
+-  build_server_array(); 
+ }
+ 
+ /* Return zero if no servers found, in that case we keep polling.
+-- 
+2.31.1
+

dnsmasq.spec

@@ -20,7 +20,7 @@
 
 Name:           dnsmasq
 Version:        2.86
-Release:        2%{?extraversion:.%{extraversion}}%{?dist}
+Release:        3%{?extraversion:.%{extraversion}}%{?dist}
 Summary:        A lightweight DHCP/caching DNS server
 
 License:        GPLv2 or GPLv3
@@ -59,6 +59,9 @@ Patch23:         0014-Fix-coverity-detected-issues-in-dnsmasq.c.patch
 Patch24:         0015-Fix-coverity-issues-in-dnssec.c.patch
 # https://bugzilla.redhat.com/show_bug.cgi?id=2006367
 Patch25:         dnsmasq-2.86-domain-match-local.patch
+# https://bugzilla.redhat.com/show_bug.cgi?id=2009975
+# replaces/enhances http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=d290630d31f4517ab26392d00753d1397f9a4114
+Patch26:         dnsmasq-2.86-build_server_array.patch
 
 
 
@@ -202,6 +205,9 @@ install -Dpm 644 %{SOURCE2} %{buildroot}%{_sysusersdir}/%{name}.conf
 %{_mandir}/man1/dhcp_*
 
 %changelog
+* Thu Oct 14 2021 Petr Menšík <pemensik@redhat.com> - 2.86-3
+- Rebuild server_array on any server change (#2009975)
+
 * Thu Sep 23 2021 Petr Menšík <pemensik@redhat.com> - 2.86-2
 - Attempt to fix regression found on recent release (#2006367)