journalctl: rotation is not a reason to warn, but certainly noteworthy

Downgrade the phrasing, since it is a bit misleading.

Fixes: #18465

.packit.yml

@@ -43,5 +43,3 @@ jobs:
     - fedora-rawhide-aarch64
     - fedora-rawhide-i386
     - fedora-rawhide-x86_64
-    - fedora-eln-aarch64
-    - fedora-eln-x86_64

TODO

@@ -20,6 +20,13 @@ Janitorial Clean-ups:
 
 Features:
 
+* Hook up journald's FSS logic with TPM2: seal the verification disk by
+  time-based policy, so that the verification key can remain on host and ve
+  validated via TPM.
+
+* sd-event: port to new kernel API epoll_wait2() (new in 5.11), to get more
+  accurate wait timeouts
+
 * sd-boot: define a drop-in dir in the ESP that may contain X.509
   certificates. If the firmware is detected to be in setup mode, automatically
   enroll them as PK/KEK/db, turn off setup mode and proceed. Optionally,

hwdb.d/60-keyboard.hwdb

@@ -662,7 +662,7 @@ evdev:atkbd:dmi:bvn*:bvr*:bd*:svnHewlett-Packard*:pnHPEliteBookFolio1040G2:*
 # HP EliteBook Folio G1
 evdev:atkbd:dmi:bvn*:bvr*:bd*:svnHP:pnHPEliteBookFolioG1:*
  KEYBOARD_KEY_64=calendar
- KEYBOARD_KEY_81=micmute
+ KEYBOARD_KEY_81=f20
 
 # HP ProBook 650
 evdev:atkbd:dmi:bvn*:bvr*:bd*:svnHewlett-Packard*:pnHP*ProBook*650*:*

src/basic/unit-file.c

@@ -354,10 +354,16 @@ int unit_file_build_name_map(
 
                                 /* Check if the symlink goes outside of our search path.
                                  * If yes, it's a linked unit file or mask, and we don't care about the target name.
-                                 * Let's just store the link destination directly.
+                                 * Let's just store the link source directly.
                                  * If not, let's verify that it's a good symlink. */
                                 char *tail = path_startswith_strv(simplified, lp->search_path);
-                                if (tail) {
+                                if (!tail) {
+                                        log_debug("%s: linked unit file: %s → %s",
+                                                  __func__, filename, simplified);
+
+                                        dst = filename;
+                                } else {
+
                                         bool self_alias;
 
                                         dst = basename(simplified);
@@ -380,10 +386,6 @@ int unit_file_build_name_map(
                                         }
 
                                         log_debug("%s: alias: %s/%s → %s", __func__, *dir, de->d_name, dst);
-                                } else {
-                                        dst  = simplified;
-
-                                        log_debug("%s: linked unit file: %s/%s → %s", __func__, *dir, de->d_name, dst);
                                 }
 
                         } else {

src/core/load-fragment.c

@@ -5536,10 +5536,11 @@ int unit_load_fragment(Unit *u) {
                 }
         }
 
-        /* We do the merge dance here because for some unit types, the unit might have aliases which are not
+        /* Call merge_by_names with the name derived from the fragment path as the preferred name.
+         *
+         * We do the merge dance here because for some unit types, the unit might have aliases which are not
          * declared in the file system. In particular, this is true (and frequent) for device and swap units.
          */
-        Unit *merged;
         const char *id = u->id;
         _cleanup_free_ char *free_id = NULL;
 
@@ -5556,7 +5557,7 @@ int unit_load_fragment(Unit *u) {
                 }
         }
 
-        merged = u;
+        Unit *merged = u;
         r = merge_by_names(&merged, names, id);
         if (r < 0)
                 return r;

src/resolve/resolved-dns-packet.h

@@ -82,7 +82,7 @@ struct DnsPacket {
         bool canonical_form:1;
 };
 
-static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
+static inline uint8_t* DNS_PACKET_DATA(const DnsPacket *p) {
         if (_unlikely_(!p))
                 return NULL;
 

src/resolve/resolved-dns-query.c

@@ -382,6 +382,13 @@ DnsQuery *dns_query_free(DnsQuery *q) {
                 varlink_unref(q->varlink_request);
         }
 
+        if (q->request_packet)
+                hashmap_remove_value(q->stub_listener_extra ?
+                                     q->stub_listener_extra->queries_by_packet :
+                                     q->manager->stub_queries_by_packet,
+                                     q->request_packet,
+                                     q);
+
         dns_packet_unref(q->request_packet);
         dns_answer_unref(q->reply_answer);
         dns_answer_unref(q->reply_authoritative);

src/resolve/resolved-dns-scope.c

@@ -153,16 +153,19 @@ unsigned dns_scope_get_n_dns_servers(DnsScope *s) {
         return n;
 }
 
-void dns_scope_next_dns_server(DnsScope *s) {
+void dns_scope_next_dns_server(DnsScope *s, DnsServer *if_current) {
         assert(s);
 
         if (s->protocol != DNS_PROTOCOL_DNS)
                 return;
 
+        /* Changes to the next DNS server in the list. If 'if_current' is passed will do so only if the
+         * current DNS server still matches it. */
+
         if (s->link)
-                link_next_dns_server(s->link);
+                link_next_dns_server(s->link, if_current);
         else
-                manager_next_dns_server(s->manager);
+                manager_next_dns_server(s->manager, if_current);
 }
 
 void dns_scope_packet_received(DnsScope *s, usec_t rtt) {
@@ -459,7 +462,7 @@ int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *add
         return dns_scope_socket(s, SOCK_STREAM, family, address, server, port, ret_socket_address);
 }
 
-static DnsScopeMatch accept_link_local_reverse_lookups(const char *domain) {
+static DnsScopeMatch match_link_local_reverse_lookups(const char *domain) {
         assert(domain);
 
         if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0)
@@ -568,29 +571,25 @@ DnsScopeMatch dns_scope_good_domain(
                         return DNS_SCOPE_YES_BASE + n_best;
                 }
 
-                /* See if this scope is suitable as default route. */
+                /* Exclude link-local IP ranges */
+                if (match_link_local_reverse_lookups(domain) >= DNS_SCOPE_YES_BASE ||
+                    /* If networks use .local in their private setups, they are supposed to also add .local
+                     * to their search domains, which we already checked above. Otherwise, we consider .local
+                     * specific to mDNS and won't send such queries ordinary DNS servers. */
+                    dns_name_endswith(domain, "local") > 0)
+                        return DNS_SCOPE_NO;
+
+                /* If there was no match at all, then see if this scope is suitable as default route. */
                 if (!dns_scope_is_default_route(s))
                         return DNS_SCOPE_NO;
 
-                /* Exclude link-local IP ranges */
+                return DNS_SCOPE_MAYBE;
-                if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
-                    dns_name_endswith(domain, "8.e.f.ip6.arpa") == 0 &&
-                    dns_name_endswith(domain, "9.e.f.ip6.arpa") == 0 &&
-                    dns_name_endswith(domain, "a.e.f.ip6.arpa") == 0 &&
-                    dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0 &&
-                    /* If networks use .local in their private setups, they are supposed to also add .local to their search
-                     * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't
-                     * send such queries ordinary DNS servers. */
-                    dns_name_endswith(domain, "local") == 0)
-                        return DNS_SCOPE_MAYBE;
-
-                return DNS_SCOPE_NO;
         }
 
         case DNS_PROTOCOL_MDNS: {
                 DnsScopeMatch m;
 
-                m = accept_link_local_reverse_lookups(domain);
+                m = match_link_local_reverse_lookups(domain);
                 if (m >= 0)
                         return m;
 
@@ -609,7 +608,7 @@ DnsScopeMatch dns_scope_good_domain(
         case DNS_PROTOCOL_LLMNR: {
                 DnsScopeMatch m;
 
-                m = accept_link_local_reverse_lookups(domain);
+                m = match_link_local_reverse_lookups(domain);
                 if (m >= 0)
                         return m;
 

src/resolve/resolved-dns-scope.h

@@ -80,7 +80,7 @@ bool dns_scope_good_key(DnsScope *s, const DnsResourceKey *key);
 
 DnsServer *dns_scope_get_dns_server(DnsScope *s);
 unsigned dns_scope_get_n_dns_servers(DnsScope *s);
-void dns_scope_next_dns_server(DnsScope *s);
+void dns_scope_next_dns_server(DnsScope *s, DnsServer *if_current);
 
 int dns_scope_llmnr_membership(DnsScope *s, bool b);
 int dns_scope_mdns_membership(DnsScope *s, bool b);

src/resolve/resolved-dns-server.c

@@ -771,23 +771,25 @@ DnsServer *manager_get_dns_server(Manager *m) {
         return m->current_dns_server;
 }
 
-void manager_next_dns_server(Manager *m) {
+void manager_next_dns_server(Manager *m, DnsServer *if_current) {
         assert(m);
 
-        /* If there's currently no DNS server set, then the next
+        /* If the DNS server is already a different one than the one specified in 'if_current' don't do anything */
-         * manager_get_dns_server() will find one */
+        if (if_current && m->current_dns_server != if_current)
+                return;
+
+        /* If there's currently no DNS server set, then the next manager_get_dns_server() will find one */
         if (!m->current_dns_server)
                 return;
 
-        /* Change to the next one, but make sure to follow the linked
+        /* Change to the next one, but make sure to follow the linked list only if the server is still
-         * list only if the server is still linked. */
+         * linked. */
         if (m->current_dns_server->linked && m->current_dns_server->servers_next) {
                 manager_set_dns_server(m, m->current_dns_server->servers_next);
                 return;
         }
 
-        /* If there was no next one, then start from the beginning of
+        /* If there was no next one, then start from the beginning of the list */
-         * the list */
         if (m->current_dns_server->type == DNS_SERVER_FALLBACK)
                 manager_set_dns_server(m, m->fallback_dns_servers);
         else

src/resolve/resolved-dns-server.h

@@ -143,7 +143,7 @@ DnsServer *manager_get_first_dns_server(Manager *m, DnsServerType t);
 
 DnsServer *manager_set_dns_server(Manager *m, DnsServer *s);
 DnsServer *manager_get_dns_server(Manager *m);
-void manager_next_dns_server(Manager *m);
+void manager_next_dns_server(Manager *m, DnsServer *if_current);
 
 DnssecMode dns_server_get_dnssec_mode(DnsServer *s);
 DnsOverTlsMode dns_server_get_dns_over_tls_mode(DnsServer *s);

src/resolve/resolved-dns-stub.c

@@ -82,6 +82,8 @@ DnsStubListenerExtra *dns_stub_listener_extra_free(DnsStubListenerExtra *p) {
         p->udp_event_source = sd_event_source_unref(p->udp_event_source);
         p->tcp_event_source = sd_event_source_unref(p->tcp_event_source);
 
+        hashmap_free(p->queries_by_packet);
+
         return mfree(p);
 }
 
@@ -94,6 +96,47 @@ uint16_t dns_stub_listener_extra_port(DnsStubListenerExtra *p) {
         return 53;
 }
 
+static void stub_packet_hash_func(const DnsPacket *p, struct siphash *state) {
+        assert(p);
+
+        siphash24_compress(&p->protocol, sizeof(p->protocol), state);
+        siphash24_compress(&p->family, sizeof(p->family), state);
+        siphash24_compress(&p->sender, sizeof(p->sender), state);
+        siphash24_compress(&p->ipproto, sizeof(p->ipproto), state);
+        siphash24_compress(&p->sender_port, sizeof(p->sender_port), state);
+        siphash24_compress(DNS_PACKET_HEADER(p), sizeof(DnsPacketHeader), state);
+
+        /* We don't bother hashing the full packet here, just the header */
+}
+
+static int stub_packet_compare_func(const DnsPacket *x, const DnsPacket *y) {
+        int r;
+
+        r = CMP(x->protocol, y->protocol);
+        if (r != 0)
+                return r;
+
+        r = CMP(x->family, y->family);
+        if (r != 0)
+                return r;
+
+        r = memcmp(&x->sender, &y->sender, sizeof(x->sender));
+        if (r != 0)
+                return r;
+
+        r = CMP(x->ipproto, y->ipproto);
+        if (r != 0)
+                return r;
+
+        r = CMP(x->sender_port, y->sender_port);
+        if (r != 0)
+                return r;
+
+        return memcmp(DNS_PACKET_HEADER(x), DNS_PACKET_HEADER(y), sizeof(DnsPacketHeader));
+}
+
+DEFINE_HASH_OPS(stub_packet_hash_ops, DnsPacket, stub_packet_hash_func, stub_packet_compare_func);
+
 static int dns_stub_collect_answer_by_question(
                 DnsAnswer **reply,
                 DnsAnswer *answer,
@@ -685,6 +728,8 @@ static int dns_stub_stream_complete(DnsStream *s, int error) {
 
 static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStream *s, DnsPacket *p) {
         _cleanup_(dns_query_freep) DnsQuery *q = NULL;
+        Hashmap **queries_by_packet;
+        DnsQuery *existing;
         int r;
 
         assert(m);
@@ -703,6 +748,13 @@ static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStrea
                 return;
         }
 
+        queries_by_packet = l ? &l->queries_by_packet : &m->stub_queries_by_packet;
+        existing = hashmap_get(*queries_by_packet, p);
+        if (existing && dns_packet_equal(existing->request_packet, p)) {
+                log_debug("Got repeat packet from client, ignoring.");
+                return;
+        }
+
         r = dns_packet_extract(p);
         if (r < 0) {
                 log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m");
@@ -735,6 +787,12 @@ static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStrea
                 return;
         }
 
+        r = hashmap_ensure_allocated(queries_by_packet, &stub_packet_hash_ops);
+        if (r < 0) {
+                log_oom();
+                return;
+        }
+
         if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) {
                 log_debug("Got request with DNSSEC checking disabled, enabling bypass logic.");
 
@@ -774,6 +832,11 @@ static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStrea
                 assert(r > 0);
         }
 
+        /* Add the query to the hash table we use to determine repeat packets now. We don't care about
+         * failures here, since in the worst case we'll not recognize duplicate incoming requests, which
+         * isn't particularly bad. */
+        (void) hashmap_put(*queries_by_packet, q->request_packet, q);
+
         r = dns_query_go(q);
         if (r < 0) {
                 log_error_errno(r, "Failed to start query: %m");

src/resolve/resolved-dns-stub.h

@@ -27,6 +27,8 @@ struct DnsStubListenerExtra {
 
         sd_event_source *udp_event_source;
         sd_event_source *tcp_event_source;
+
+        Hashmap *queries_by_packet;
 };
 
 extern const struct hash_ops dns_stub_listener_extra_hash_ops;

src/resolve/resolved-dns-transaction.c

@@ -484,7 +484,7 @@ static void dns_transaction_retry(DnsTransaction *t, bool next_server) {
 
         /* Before we try again, switch to a new server. */
         if (next_server)
-                dns_scope_next_dns_server(t->scope);
+                dns_scope_next_dns_server(t->scope, t->server);
 
         r = dns_transaction_go(t);
         if (r < 0)
@@ -1859,7 +1859,7 @@ int dns_transaction_go(DnsTransaction *t) {
                 /* One of our own stub listeners */
                 log_debug_errno(r, "Detected that specified DNS server is our own extra listener, switching DNS servers.");
 
-                dns_scope_next_dns_server(t->scope);
+                dns_scope_next_dns_server(t->scope, t->server);
 
                 if (dns_scope_get_dns_server(t->scope) == t->server) {
                         log_debug_errno(r, "Still pointing to extra listener after switching DNS servers, refusing operation.");
@@ -1890,7 +1890,7 @@ int dns_transaction_go(DnsTransaction *t) {
                         return r;
 
                 /* Couldn't send? Try immediately again, with a new server */
-                dns_scope_next_dns_server(t->scope);
+                dns_scope_next_dns_server(t->scope, t->server);
 
                 return dns_transaction_go(t);
         }

src/resolve/resolved-link.c

@@ -731,19 +731,27 @@ DnsServer *link_get_dns_server(Link *l) {
         return l->current_dns_server;
 }
 
-void link_next_dns_server(Link *l) {
+void link_next_dns_server(Link *l, DnsServer *if_current) {
         assert(l);
 
+        /* If the current server of the transaction is specified, and we already are at a different one,
+         * don't do anything */
+        if (if_current && l->current_dns_server != if_current)
+                return;
+
+        /* If currently have no DNS server, then don't do anything, we'll pick it lazily the next time a DNS
+         * server is needed. */
         if (!l->current_dns_server)
                 return;
 
-        /* Change to the next one, but make sure to follow the linked
+        /* Change to the next one, but make sure to follow the linked list only if this server is actually
-         * list only if this server is actually still linked. */
+         * still linked. */
         if (l->current_dns_server->linked && l->current_dns_server->servers_next) {
                 link_set_dns_server(l, l->current_dns_server->servers_next);
                 return;
         }
 
+        /* Pick the first one again, after we reached the end */
         link_set_dns_server(l, l->dns_servers);
 }
 

src/resolve/resolved-link.h

@@ -91,7 +91,7 @@ void link_allocate_scopes(Link *l);
 
 DnsServer* link_set_dns_server(Link *l, DnsServer *s);
 DnsServer* link_get_dns_server(Link *l);
-void link_next_dns_server(Link *l);
+void link_next_dns_server(Link *l, DnsServer *if_current);
 
 DnssecMode link_get_dnssec_mode(Link *l);
 bool link_dnssec_supported(Link *l);

src/resolve/resolved-manager.c

@@ -739,6 +739,8 @@ Manager *manager_free(Manager *m) {
         while (m->dns_queries)
                 dns_query_free(m->dns_queries);
 
+        m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
+
         dns_scope_free(m->unicast_scope);
 
         /* At this point only orphaned streams should remain. All others should have been freed already by their

src/resolve/resolved-manager.h

@@ -59,6 +59,7 @@ struct Manager {
         Hashmap *dns_transactions;
         LIST_HEAD(DnsQuery, dns_queries);
         unsigned n_dns_queries;
+        Hashmap *stub_queries_by_packet;
 
         LIST_HEAD(DnsStream, dns_streams);
         unsigned n_dns_streams[_DNS_STREAM_TYPE_MAX];
@@ -97,13 +98,12 @@ struct Manager {
         /* mDNS */
         int mdns_ipv4_fd;
         int mdns_ipv6_fd;
+        sd_event_source *mdns_ipv4_event_source;
+        sd_event_source *mdns_ipv6_event_source;
 
         /* DNS-SD */
         Hashmap *dnssd_services;
 
-        sd_event_source *mdns_ipv4_event_source;
-        sd_event_source *mdns_ipv6_event_source;
-
         /* dbus */
         sd_bus *bus;
 

src/shared/logs-show.c

@@ -1398,7 +1398,7 @@ int show_journal(
                         if (line == 0 && noaccess)
                                 fprintf(f, "Warning: some journal files were not opened due to insufficient permissions.");
                         else if (!noaccess)
-                                fprintf(f, "Warning: journal has been rotated since unit was started, output may be incomplete.\n");
+                                fprintf(f, "Notice: journal has been rotated since unit was started, output may be incomplete.\n");
                         else
                                 fprintf(f, "Warning: journal has been rotated since unit was started and some journal "
                                         "files were not opened due to insufficient permissions, output may be incomplete.\n");

src/systemctl/systemctl.c

@@ -912,57 +912,53 @@ int systemctl_dispatch_parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
-        if (program_invocation_short_name) {
+        if (strstr_ptr(argv[0], "halt")) {
+                arg_action = ACTION_HALT;
+                return halt_parse_argv(argc, argv);
 
-                if (strstr(program_invocation_short_name, "halt")) {
+        } else if (strstr_ptr(argv[0], "poweroff")) {
-                        arg_action = ACTION_HALT;
+                arg_action = ACTION_POWEROFF;
-                        return halt_parse_argv(argc, argv);
+                return halt_parse_argv(argc, argv);
 
-                } else if (strstr(program_invocation_short_name, "poweroff")) {
+        } else if (strstr_ptr(argv[0], "reboot")) {
-                        arg_action = ACTION_POWEROFF;
+                if (kexec_loaded())
-                        return halt_parse_argv(argc, argv);
+                        arg_action = ACTION_KEXEC;
+                else
+                        arg_action = ACTION_REBOOT;
+                return halt_parse_argv(argc, argv);
 
-                } else if (strstr(program_invocation_short_name, "reboot")) {
+        } else if (strstr_ptr(argv[0], "shutdown")) {
-                        if (kexec_loaded())
+                arg_action = ACTION_POWEROFF;
-                                arg_action = ACTION_KEXEC;
+                return shutdown_parse_argv(argc, argv);
-                        else
-                                arg_action = ACTION_REBOOT;
-                        return halt_parse_argv(argc, argv);
 
-                } else if (strstr(program_invocation_short_name, "shutdown")) {
+        } else if (strstr_ptr(argv[0], "init")) {
-                        arg_action = ACTION_POWEROFF;
-                        return shutdown_parse_argv(argc, argv);
 
-                } else if (strstr(program_invocation_short_name, "init")) {
+                /* Matches invocations as "init" as well as "telinit", which are synonymous when run
+                 * as PID != 1 on SysV.
+                 *
+                 * On SysV "telinit" was the official command to communicate with PID 1, but "init" would
+                 * redirect itself to "telinit" if called with PID != 1. We follow the same logic here still,
+                 * though we add one level of indirection, as we implement "telinit" in "systemctl". Hence,
+                 * for us if you invoke "init" you get "systemd", but it will execve() "systemctl"
+                 * immediately with argv[] unmodified if PID is != 1. If you invoke "telinit" you directly
+                 * get "systemctl". In both cases we shall do the same thing, which is why we do
+                 * strstr_ptr(argv[0], "init") here, as a quick way to match both.
+                 *
+                 * Also see redirect_telinit() in src/core/main.c. */
 
-                        /* Matches invocations as "init" as well as "telinit", which are synonymous when run
+                if (sd_booted() > 0) {
-                         * as PID != 1 on SysV.
+                        arg_action = _ACTION_INVALID;
-                         *
+                        return telinit_parse_argv(argc, argv);
-                         * On SysV "telinit" was the official command to communicate with PID 1, but "init" would
+                } else {
-                         * redirect itself to "telinit" if called with PID != 1. We follow the same logic here still,
+                        /* Hmm, so some other init system is running, we need to forward this request to it.
-                         * though we add one level of indirection, as we implement "telinit" in "systemctl". Hence, for
+                         */
-                         * us if you invoke "init" you get "systemd", but it will execve() "systemctl" immediately with
+                        arg_action = ACTION_TELINIT;
-                         * argv[] unmodified if PID is != 1. If you invoke "telinit" you directly get "systemctl". In
+                        return 1;
-                         * both cases we shall do the same thing, which is why we do strstr(p_i_s_n, "init") here, as a
-                         * quick way to match both.
-                         *
-                         * Also see redirect_telinit() in src/core/main.c. */
-
-                        if (sd_booted() > 0) {
-                                arg_action = _ACTION_INVALID;
-                                return telinit_parse_argv(argc, argv);
-                        } else {
-                                /* Hmm, so some other init system is running, we need to forward this request
-                                 * to it. */
-
-                                arg_action = ACTION_TELINIT;
-                                return 1;
-                        }
-
-                } else if (strstr(program_invocation_short_name, "runlevel")) {
-                        arg_action = ACTION_RUNLEVEL;
-                        return runlevel_parse_argv(argc, argv);
                 }
+
+        } else if (strstr_ptr(argv[0], "runlevel")) {
+                arg_action = ACTION_RUNLEVEL;
+                return runlevel_parse_argv(argc, argv);
         }
 
         arg_action = ACTION_SYSTEMCTL;

test/units/testsuite-15.sh

@@ -124,6 +124,32 @@ EOF
     clear_services test15-a test15-b test15-c
 }
 
+test_linked_units () {
+    echo "Testing linked units..."
+    echo "*** test linked unit (same basename)"
+
+    create_service test15-a
+    mv /etc/systemd/system/test15-a.service /
+    ln -s /test15-a.service /etc/systemd/system/
+    ln -s test15-a.service /etc/systemd/system/test15-b.service
+
+    check_ok test15-a Names test15-a.service
+    check_ok test15-a Names test15-b.service
+
+    echo "*** test linked unit (cross basename)"
+
+    mv /test15-a.service /test15-a@.scope
+    ln -fs /test15-a@.scope /etc/systemd/system/test15-a.service
+    systemctl daemon-reload
+
+    check_ok test15-a Names test15-a.service
+    check_ok test15-a Names test15-b.service
+    check_ko test15-a Names test15-b@
+
+    rm /test15-a@.scope
+    clear_services test15-a test15-b
+}
+
 test_hierarchical_dropins () {
     echo "Testing hierarchical dropins..."
     echo "*** test service.d/ top level drop-in"
@@ -465,6 +491,7 @@ test_invalid_dropins () {
 }
 
 test_basic_dropins
+test_linked_units
 test_hierarchical_dropins
 test_template_dropins
 test_alias_dropins