resolvectl: Only strip ifname suffixes when being resolvconf

Only treat interface names containing dots specially when resolvectl is
pretending to be resolvconf to fix
https://github.com/systemd/systemd/issues/20014 .

Move the special suffix-stripping behaviour of ifname_mangle out to the
new ifname_resolvconf_mangle to be called from resolvconf only.

(cherry picked from commit 7875170f01991a1d28cfe284cc7075630cd69055)
(cherry picked from commit 6ec5680beaa8df4b4b87e9aa614d29561c0e98fe)

3 files changed, 21 insertions, 9 deletions

diff --git a/src/resolve/resolvconf-compat.c b/src/resolve/resolvconf-compat.c
index 5bc936faa7..8dc559801d 100644
--- a/src/resolve/resolvconf-compat.c
+++ b/src/resolve/resolvconf-compat.c
@@ -212,7 +212,7 @@ int resolvconf_parse_argv(int argc, char *argv[]) {
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                        "Expected interface name as argument.");
 
-        r = ifname_mangle(argv[optind]);
+        r = ifname_resolvconf_mangle(argv[optind]);
         if (r <= 0)
                 return r;
 
diff --git a/src/resolve/resolvectl.c b/src/resolve/resolvectl.c
index b479335769..3a805245de 100644
--- a/src/resolve/resolvectl.c
+++ b/src/resolve/resolvectl.c
@@ -100,18 +100,11 @@ static int interface_info_compare(const InterfaceInfo *a, const InterfaceInfo *b
 
 int ifname_mangle(const char *s) {
         _cleanup_free_ char *iface = NULL;
-        const char *dot;
         int ifi;
 
         assert(s);
 
-        dot = strchr(s, '.');
-        if (dot) {
-                log_debug("Ignoring protocol specifier '%s'.", dot + 1);
-                iface = strndup(s, dot - s);
-
-        } else
-                iface = strdup(s);
+        iface = strdup(s);
         if (!iface)
                 return log_oom();
 
@@ -134,6 +127,24 @@ int ifname_mangle(const char *s) {
         return 1;
 }
 
+int ifname_resolvconf_mangle(const char *s) {
+        const char *dot;
+
+        assert(s);
+
+        dot = strchr(s, '.');
+        if (dot) {
+                _cleanup_free_ char *iface = NULL;
+
+                log_debug("Ignoring protocol specifier '%s'.", dot + 1);
+                iface = strndup(s, dot - s);
+                if (!iface)
+                        return log_oom();
+                return ifname_mangle(iface);
+        } else
+                return ifname_mangle(s);
+}
+
 static void print_source(uint64_t flags, usec_t rtt) {
         char rtt_str[FORMAT_TIMESTAMP_MAX];
 
diff --git a/src/resolve/resolvectl.h b/src/resolve/resolvectl.h
index 830c81d692..3d55bf78da 100644
--- a/src/resolve/resolvectl.h
+++ b/src/resolve/resolvectl.h
@@ -27,3 +27,4 @@ extern char **arg_set_domain;
 extern bool arg_ifindex_permissive;
 
 int ifname_mangle(const char *s);
+int ifname_resolvconf_mangle(const char *s);