bus-util: Log more information when connecting to a bus socket fails

Let's log about which bus we're trying to connect to and what transport
we're using to do it.

src/analyze/analyze-blame.c

@@ -14,7 +14,7 @@ int verb_blame(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         n = acquire_time_data(bus, /* require_finished = */ false, &times);
         if (n <= 0)

src/analyze/analyze-critical-chain.c

@@ -200,7 +200,7 @@ int verb_critical_chain(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         n = acquire_time_data(bus, /* require_finished = */ true, &times);
         if (n <= 0)

src/analyze/analyze-dot.c

@@ -149,7 +149,7 @@ int verb_dot(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         r = expand_patterns(bus, strv_skip(argv, 1), &expanded_patterns);
         if (r < 0)

src/analyze/analyze-dump.c

@@ -123,7 +123,7 @@ int verb_dump(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         pager_open(arg_pager_flags);
 

src/analyze/analyze-fdstore.c

@@ -98,7 +98,7 @@ int verb_fdstore(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         STRV_FOREACH(arg, strv_skip(argv, 1)) {
                 r = dump_fdstore(bus, *arg);

src/analyze/analyze-log-control.c

@@ -12,7 +12,7 @@ int verb_log_control(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         r = verb_log_control_common(bus, "org.freedesktop.systemd1", argv[0], argc == 2 ? argv[1] : NULL);
         if (r < 0)

src/analyze/analyze-malloc.c

@@ -43,7 +43,7 @@ int verb_malloc(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
         if (r < 0)

src/analyze/analyze-plot.c

@@ -473,7 +473,7 @@ int verb_plot(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, &use_full_bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         n = acquire_boot_times(bus, /* require_finished = */ true, &boot);
         if (n < 0)

src/analyze/analyze-security.c

@@ -2904,7 +2904,7 @@ int verb_security(int argc, char *argv[], void *userdata) {
         if (!arg_offline) {
                 r = acquire_bus(&bus, NULL);
                 if (r < 0)
-                        return bus_log_connect_error(r, arg_transport);
+                        return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
         }
 
         pager_open(arg_pager_flags);

src/analyze/analyze-service-watchdogs.c

@@ -16,7 +16,7 @@ int verb_service_watchdogs(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         if (argc == 1) {
                 /* get ServiceWatchdogs */

src/analyze/analyze-time.c

@@ -11,7 +11,7 @@ int verb_time(int argc, char *argv[], void *userdata) {
 
         r = acquire_bus(&bus, NULL);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         r = pretty_boot_time(bus, &buf);
         if (r < 0)

src/busctl/busctl.c

@@ -153,7 +153,7 @@ static int acquire_bus(bool set_monitor, sd_bus **ret) {
 
         r = sd_bus_start(bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         *ret = TAKE_PTR(bus);
 

src/cgls/cgls.c

@@ -221,13 +221,12 @@ static int run(int argc, char *argv[]) {
                                         return log_error_errno(r, "Failed to mangle unit name: %m");
 
                                 if (!bus) {
+                                        RuntimeScope scope = arg_show_unit == SHOW_UNIT_USER ? RUNTIME_SCOPE_USER : RUNTIME_SCOPE_SYSTEM;
+
                                         /* Connect to the bus only if necessary */
-                                        r = bus_connect_transport_systemd(
-                                                        BUS_TRANSPORT_LOCAL, NULL,
-                                                        arg_show_unit == SHOW_UNIT_USER ? RUNTIME_SCOPE_USER : RUNTIME_SCOPE_SYSTEM,
-                                                        &bus);
+                                        r = bus_connect_transport_systemd(BUS_TRANSPORT_LOCAL, NULL, scope, &bus);
                                         if (r < 0)
-                                                return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL);
+                                                return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL, scope);
                                 }
 
                                 q = show_cgroup_get_unit_path_and_warn(bus, unit_name, &cgroup);

src/firstboot/firstboot.c

@@ -1558,7 +1558,7 @@ static int reload_system_manager(sd_bus **bus) {
         if (!*bus) {
                 r = bus_connect_transport_systemd(BUS_TRANSPORT_LOCAL, NULL, RUNTIME_SCOPE_SYSTEM, bus);
                 if (r < 0)
-                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL);
+                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL, RUNTIME_SCOPE_SYSTEM);
         }
 
         r = bus_service_manager_reload(*bus);
@@ -1581,7 +1581,7 @@ static int reload_vconsole(sd_bus **bus) {
         if (!*bus) {
                 r = bus_connect_transport_systemd(BUS_TRANSPORT_LOCAL, NULL, RUNTIME_SCOPE_SYSTEM, bus);
                 if (r < 0)
-                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL);
+                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL, RUNTIME_SCOPE_SYSTEM);
         }
 
         r = bus_wait_for_jobs_new(*bus, &w);

src/home/homectl.c

@@ -135,7 +135,7 @@ static int acquire_bus(sd_bus **bus) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(*bus, arg_ask_password);
 

src/hostname/hostnamectl.c

@@ -813,7 +813,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         return hostnamectl_main(bus, argc, argv);
 }

src/import/importctl.c

@@ -1240,7 +1240,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/locale/localectl.c

@@ -536,7 +536,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         return localectl_main(bus, argc, argv);
 }

src/login/inhibit.c

@@ -275,7 +275,7 @@ static int run(int argc, char *argv[]) {
 
         r = sd_bus_default_system(&bus);
         if (r < 0)
-                return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL);
+                return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/login/loginctl.c

@@ -1723,7 +1723,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/machine/machinectl.c

@@ -2445,7 +2445,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/mount/mount-tool.c

@@ -1513,7 +1513,7 @@ static int run(int argc, char* argv[]) {
 
         r = bus_connect_transport_systemd(arg_transport, arg_host, arg_runtime_scope, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/portable/portablectl.c

@@ -229,7 +229,7 @@ static int acquire_bus(sd_bus **bus) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(*bus, arg_ask_password);
 

src/run/run.c

@@ -2439,7 +2439,7 @@ static int run(int argc, char* argv[]) {
         else
                 r = bus_connect_transport_systemd(arg_transport, arg_host, arg_runtime_scope, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);
 

src/shared/bus-util.c

@@ -29,6 +29,7 @@
 #include "path-util.h"
 #include "socket-util.h"
 #include "stdio-util.h"
+#include "string-table.h"
 #include "uid-classification.h"
 
 static int name_owner_change_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
@@ -50,14 +51,14 @@ int bus_log_address_error(int r, BusTransport transport) {
                                       "Failed to set bus address: %m");
 }
 
-int bus_log_connect_error(int r, BusTransport transport) {
+int bus_log_connect_error(int r, BusTransport transport, RuntimeScope scope) {
         bool hint_vars = transport == BUS_TRANSPORT_LOCAL && r == -ENOMEDIUM,
              hint_addr = transport == BUS_TRANSPORT_LOCAL && ERRNO_IS_PRIVILEGE(r);
 
         return log_error_errno(r,
-                               r == hint_vars ? "Failed to connect to bus: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)" :
-                               r == hint_addr ? "Failed to connect to bus: Operation not permitted (consider using --machine=<user>@.host --user to connect to bus of other user)" :
-                                                "Failed to connect to bus: %m");
+                               r == hint_vars ? "Failed to connect to %s scope bus via %s transport: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined (consider using --machine=<user>@.host --user to connect to bus of other user)" :
+                               r == hint_addr ? "Failed to connect to %s scope bus via %s transport: Operation not permitted (consider using --machine=<user>@.host --user to connect to bus of other user)" :
+                                                "Failed to connect to %s scope bus via %s transport: %m", runtime_scope_to_string(scope), bus_transport_to_string(transport));
 }
 
 int bus_async_unregister_and_exit(sd_event *e, sd_bus *bus, const char *name) {
@@ -944,3 +945,12 @@ int bus_message_read_id128(sd_bus_message *m, sd_id128_t *ret) {
                 return -EINVAL;
         }
 }
+
+static const char* const bus_transport_table[] = {
+        [BUS_TRANSPORT_LOCAL]   = "local",
+        [BUS_TRANSPORT_REMOTE]  = "remote",
+        [BUS_TRANSPORT_MACHINE] = "machine",
+        [BUS_TRANSPORT_CAPSULE] = "capsule",
+};
+
+DEFINE_STRING_TABLE_LOOKUP_TO_STRING(bus_transport, BusTransport);

src/shared/bus-util.h

@@ -48,7 +48,7 @@ int bus_connect_transport(BusTransport transport, const char *host, RuntimeScope
 int bus_connect_transport_systemd(BusTransport transport, const char *host, RuntimeScope runtime_scope, sd_bus **bus);
 
 int bus_log_address_error(int r, BusTransport transport);
-int bus_log_connect_error(int r, BusTransport transport);
+int bus_log_connect_error(int r, BusTransport transport, RuntimeScope scope);
 
 #define bus_log_parse_error(r)                                  \
         log_error_errno(r, "Failed to parse bus message: %m")
@@ -84,3 +84,5 @@ int bus_creds_get_pidref(sd_bus_creds *c, PidRef *ret);
 int bus_query_sender_pidref(sd_bus_message *m, PidRef *ret);
 
 int bus_message_read_id128(sd_bus_message *m, sd_id128_t *ret);
+
+const char* bus_transport_to_string(BusTransport transport) _const_;

src/shared/cgroup-show.c

@@ -434,7 +434,7 @@ int show_cgroup_get_path_and_warn(
 
                 r = bus_connect_transport_systemd(BUS_TRANSPORT_LOCAL, NULL, RUNTIME_SCOPE_SYSTEM, &bus);
                 if (r < 0)
-                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL);
+                        return bus_log_connect_error(r, BUS_TRANSPORT_LOCAL, RUNTIME_SCOPE_SYSTEM);
 
                 r = show_cgroup_get_unit_path_and_warn(bus, unit, &root);
                 if (r < 0)

src/systemctl/systemctl-util.c

@@ -54,7 +54,7 @@ int acquire_bus(BusFocus focus, sd_bus **ret) {
                 else
                         r = bus_connect_transport(arg_transport, arg_host, arg_runtime_scope, &buses[focus]);
                 if (r < 0)
-                        return bus_log_connect_error(r, arg_transport);
+                        return bus_log_connect_error(r, arg_transport, arg_runtime_scope);
 
                 (void) sd_bus_set_allow_interactive_authorization(buses[focus], arg_ask_password);
         }

src/sysupdate/updatectl.c

@@ -1299,7 +1299,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         if (arg_transport == BUS_TRANSPORT_LOCAL)
                 polkit_agent_open();

src/timedate/timedatectl.c

@@ -1063,7 +1063,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, RUNTIME_SCOPE_SYSTEM, &bus);
         if (r < 0)
-                return bus_log_connect_error(r, arg_transport);
+                return bus_log_connect_error(r, arg_transport, RUNTIME_SCOPE_SYSTEM);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);