logind: change user-runtime-dir to query runtime dir size from logind via the bus

I think this is a slightly cleaner approach than parsing the
configuration file at multiple places, as this way there's only a single
reload cycle for logind.conf, and that's systemd-logind.service's
runtime.

This means that logind and dbus become a requirement of
user-runtime-dir, but given that XDG_RUNTIME_DIR is not set anyway
without logind and dbus around this isn't really any limitation.

This also simplifies linking a bit as this means user-runtime-dir
doesn't have to link against any code of logind itself.

(cherry picked from commit 07ee5adb356b9fde500c8a5226f24a314789832b)

2 files changed, 24 insertions, 14 deletions

diff --git a/src/login/meson.build b/src/login/meson.build
index f8c536464..81f39e1ea 100644
--- a/src/login/meson.build
+++ b/src/login/meson.build
@@ -83,7 +83,6 @@ loginctl_sources = files('''
 #if 0 /// UNNEEDED by elogind
 # user_runtime_dir_sources = files('''
 #         user-runtime-dir.c
-#         logind.h
 # '''.split())
 #endif // 0
 
diff --git a/src/login/user-runtime-dir.c b/src/login/user-runtime-dir.c
index 3ba4af3f2..d482f8237 100644
--- a/src/login/user-runtime-dir.c
+++ b/src/login/user-runtime-dir.c
@@ -3,9 +3,11 @@
 #include <stdint.h>
 #include <sys/mount.h>
 
+//#include "sd-bus.h"
+
+//#include "bus-error.h"
 #include "fs-util.h"
 #include "label.h"
-//#include "logind.h"
 #include "mkdir.h"
 #include "mount-util.h"
 #include "path-util.h"
@@ -20,22 +22,29 @@
 #include "user-runtime-dir.h"
 
 #if 0 /// UNNEEDED by elogind
-static int gather_configuration(size_t *runtime_dir_size) {
-        Manager m = {};
+static int acquire_runtime_dir_size(uint64_t *ret) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
         int r;
 
-        manager_reset_config(&m);
+        r = sd_bus_default_system(&bus);
+        if (r < 0)
+                return log_error_errno(r, "Failed to connect to system bus: %m");
 
-        r = manager_parse_config_file(&m);
+        r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectorySize", &error, 't', ret);
         if (r < 0)
-                log_warning_errno(r, "Failed to parse logind.conf: %m");
+                return log_error_errno(r, "Failed to acquire runtime directory size: %s", bus_error_message(&error, r));
 
-        *runtime_dir_size = m.runtime_dir_size;
         return 0;
 }
 #endif // 0
 
-static int user_mkdir_runtime_path(const char *runtime_path, uid_t uid, gid_t gid, size_t runtime_dir_size) {
+static int user_mkdir_runtime_path(
+                const char *runtime_path,
+                uid_t uid,
+                gid_t gid,
+                uint64_t runtime_dir_size) {
+
         int r;
 
         assert(runtime_path);
@@ -53,10 +62,10 @@ static int user_mkdir_runtime_path(const char *runtime_path, uid_t uid, gid_t gi
                 char options[sizeof("mode=0700,uid=,gid=,size=,smackfsroot=*")
                              + DECIMAL_STR_MAX(uid_t)
                              + DECIMAL_STR_MAX(gid_t)
-                             + DECIMAL_STR_MAX(size_t)];
+                             + DECIMAL_STR_MAX(uint64_t)];
 
                 xsprintf(options,
-                         "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu%s",
+                         "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 "%s",
                          uid, gid, runtime_dir_size,
                          mac_smack_use() ? ",smackfsroot=*" : "");
 
@@ -118,7 +127,7 @@ static int user_remove_runtime_path(const char *runtime_path) {
 #if 0 /// having a User instance, elogind can ask its manager directly.
 static int do_mount(const char *user) {
         char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
-        size_t runtime_dir_size;
+        uint64_t runtime_dir_size;
         uid_t uid;
         gid_t gid;
         int r;
@@ -131,9 +140,11 @@ static int do_mount(const char *user) {
                                                     : "Failed to look up user \"%s\": %m",
                                        user);
 
-        xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
+        r = acquire_runtime_dir_size(&runtime_dir_size);
+        if (r < 0)
+                return r;
 
-        assert_se(gather_configuration(&runtime_dir_size) == 0);
+        xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
 #else
 static int do_mount(const char *runtime_path, size_t runtime_dir_size, uid_t uid, gid_t gid) {
 #endif // 0