hostname-util: introduce new is_gateway_hostname() call

This moves is_gateway() from nss-myhostname into the basic APIs, and
makes it more like is_localhost(). Also, we rename it to
is_gateway_hostname() to make it more expressive.

Sharing this function in src/basic/ allows us to reuse the function for
routing name requests in resolved (in a later commit).

3 files changed, 14 insertions, 9 deletions

diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c
index d901a5e82b..dc5434fcd1 100644
--- a/src/basic/hostname-util.c
+++ b/src/basic/hostname-util.c
@@ -151,6 +151,17 @@ bool is_localhost(const char *hostname) {
                endswith_no_case(hostname, ".localdomain.");
 }
 
+bool is_gateway_hostname(const char *hostname) {
+        assert(hostname);
+
+        /* This tries to identify the valid syntaxes for the our
+         * synthetic "gateway" host. */
+
+        return
+                strcaseeq(hostname, "gateway") ||
+                strcaseeq(hostname, "gateway.");
+}
+
 int sethostname_idempotent(const char *s) {
         char buf[HOST_NAME_MAX + 1] = {};
 
diff --git a/src/basic/hostname-util.h b/src/basic/hostname-util.h
index 6f2b5b66ff..a1ca94980d 100644
--- a/src/basic/hostname-util.h
+++ b/src/basic/hostname-util.h
@@ -33,6 +33,7 @@ bool hostname_is_valid(const char *s, bool relax) _pure_;
 char* hostname_cleanup(char *s);
 
 bool is_localhost(const char *hostname);
+bool is_gateway_hostname(const char *hostname);
 
 int sethostname_idempotent(const char *s);
 
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 69069cc75d..0dca891447 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -43,13 +43,6 @@
 NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
 NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);
 
-static bool is_gateway(const char *hostname) {
-        assert(hostname);
-
-        return streq(hostname, "gateway") ||
-               streq(hostname, "gateway.");
-}
-
 enum nss_status _nss_myhostname_gethostbyname4_r(
                 const char *name,
                 struct gaih_addrtuple **pat,
@@ -81,7 +74,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
                 canonical = "localhost";
                 local_address_ipv4 = htonl(INADDR_LOOPBACK);
 
-        } else if (is_gateway(name)) {
+        } else if (is_gateway_hostname(name)) {
 
                 n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
                 if (n_addresses <= 0) {
@@ -351,7 +344,7 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
                 canonical = "localhost";
                 local_address_ipv4 = htonl(INADDR_LOOPBACK);
 
-        } else if (is_gateway(name)) {
+        } else if (is_gateway_hostname(name)) {
 
                 n_addresses = local_gateways(NULL, 0, af, &addresses);
                 if (n_addresses <= 0) {