statefiles: don't write empty hosts files

This is mostly cosmetic, skip writing out hosts files for interfaces
where it makes little sense to do so (i.e. where the hosts file will
anyway be empty).

Closes: https://github.com/openwrt/odhcpd/issues/338
Signed-off-by: David Härdeman <[email protected]>
Link: https://github.com/openwrt/odhcpd/pull/342
Signed-off-by: Álvaro Fernández Rojas <[email protected]>

diff --git a/src/statefiles.c b/src/statefiles.c
index 0ce2a2ee712e87b12027740d2f5817bc154b7839..558b0120ee61d4e631beb259ba821108a562b6a1 100644 (file)
--- a/src/statefiles.c
+++ b/src/statefiles.c
@@ -415,7 +415,15 @@ static void statefiles_write_hosts(time_t now)
                return;
 
        avl_for_each_element(&interfaces, ctxt.iface, avl) {
+               if (ctxt.iface->ignore)
+                       continue;
+
+               if (ctxt.iface->dhcpv4 != MODE_SERVER && ctxt.iface->dhcpv6 != MODE_SERVER)
+                       continue;
+
                ctxt.fp = statefiles_open_tmp_file(config.dhcp_hostsdir_fd);
+               if (!ctxt.fp)
+                       continue;
 
                if (ctxt.iface->dhcpv6 == MODE_SERVER) {
                        struct dhcpv6_lease *lease;
@@ -534,6 +542,7 @@ static bool statefiles_write_state(time_t now)
        };
        uint8_t newmd5[16];
 
+       /* Return value unchecked, continue in order to get the md5 */
        ctxt.fp = statefiles_open_tmp_file(config.dhcp_statedir_fd);
 
        md5_begin(&ctxt.md5);