dns: kill pending dnsmasq process when mode is not 'dnsmasq'wl/dns

When NM starts, if `main.dns` is not `dnsmasq`, then the pending dnsmasq
process should be killed by NM.

https://bugzilla.redhat.com/show_bug.cgi?id=2120763

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1344

3 files changed, 13 insertions, 0 deletions

diff --git a/src/core/dns/nm-dns-dnsmasq.c b/src/core/dns/nm-dns-dnsmasq.c
index d88d3de681..cc7c03a21b 100644
--- a/src/core/dns/nm-dns-dnsmasq.c
+++ b/src/core/dns/nm-dns-dnsmasq.c
@@ -668,6 +668,14 @@ _gl_pid_spawn(const char           *dm_binary,
 
 /*****************************************************************************/
 
+void
+nm_dnsmasq_kill_external(void)
+{
+    _gl_pid_kill_external();
+}
+
+/*****************************************************************************/
+
 typedef struct {
     GDBusConnection *dbus_connection;
 
diff --git a/src/core/dns/nm-dns-dnsmasq.h b/src/core/dns/nm-dns-dnsmasq.h
index 575b0b263f..98761d3d9f 100644
--- a/src/core/dns/nm-dns-dnsmasq.h
+++ b/src/core/dns/nm-dns-dnsmasq.h
@@ -25,4 +25,6 @@ GType nm_dns_dnsmasq_get_type(void);
 
 NMDnsPlugin *nm_dns_dnsmasq_new(void);
 
+void nm_dnsmasq_kill_external(void);
+
 #endif /* __NETWORKMANAGER_DNS_DNSMASQ_H__ */
diff --git a/src/core/dns/nm-dns-manager.c b/src/core/dns/nm-dns-manager.c
index 1e54452aa4..16af1d2dfe 100644
--- a/src/core/dns/nm-dns-manager.c
+++ b/src/core/dns/nm-dns-manager.c
@@ -2506,6 +2506,9 @@ again:
                                                              self);
     }
 
+    if (!NM_IS_DNS_DNSMASQ(priv->plugin))
+        nm_dnsmasq_kill_external();
+
     _update_pending_maybe_changed(self);
 
     g_object_thaw_notify(G_OBJECT(self));