localed: reload PID1 configuration after modifying /etc/locale.conf

Since commit 1ad6e8b302e87b6891a2bfc35ad397b0afe3d940, unsetting an environment
variable means restoring it to its default value.

However this doesn't work well when localed updates locale.conf. Indeed when a
variable is removed from that file, localed calls "UnsetAndSetEnvironment"
method which restores the default values of the unset variables obtained by
PID1 when it first read locale.conf. But since locale.conf has been updated,
these default values might be outdated and localed needs to instruct PID1 to
read locale.conf again.

Reloading PID1 configuration is quite an heavy operation for this purpose but
there's no other way unless we change again the meaning of "UnsetEnvironment"
or we introduce a new method that really unset an env variable.

That said given the fact that localed modifies locale.conf, it should have an
effect on PID1 default environment rather than on the environment explicitly
set by the user (m->client_manager).

1 files changed, 8 insertions, 12 deletions

diff --git a/src/locale/localed.c b/src/locale/localed.c
index a2014e3da0..9b6890ebb4 100644
--- a/src/locale/localed.c
+++ b/src/locale/localed.c
@@ -32,7 +32,7 @@
 #include "strv.h"
 #include "user-util.h"
 
-static int locale_update_system_manager(sd_bus *bus, char **l_set, char **l_unset) {
+static int reload_system_manager(sd_bus *bus) {
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         int r;
@@ -43,21 +43,13 @@ static int locale_update_system_manager(sd_bus *bus, char **l_set, char **l_unse
                         "org.freedesktop.systemd1",
                         "/org/freedesktop/systemd1",
                         "org.freedesktop.systemd1.Manager",
-                        "UnsetAndSetEnvironment");
-        if (r < 0)
-                return bus_log_create_error(r);
-
-        r = sd_bus_message_append_strv(m, l_unset);
-        if (r < 0)
-                return bus_log_create_error(r);
-
-        r = sd_bus_message_append_strv(m, l_set);
+                        "Reload");
         if (r < 0)
                 return bus_log_create_error(r);
 
         r = sd_bus_call(bus, m, 0, &error, NULL);
         if (r < 0)
-                return log_error_errno(r, "Failed to update the manager environment: %s", bus_error_message(&error, r));
+                return log_error_errno(r, "Failed to reload system manager: %s", bus_error_message(&error, r));
 
         return 0;
 }
@@ -393,7 +385,11 @@ static int method_set_locale(sd_bus_message *m, void *userdata, sd_bus_error *er
                 return sd_bus_error_set_errnof(error, r, "Failed to set locale: %m");
         }
 
-        (void) locale_update_system_manager(sd_bus_message_get_bus(m), l_set, l_unset);
+        /* Since we just updated the locale configuration file, ask the system manager to read it again to
+         * update its default locale settings. It's important to not use UnsetAndSetEnvironment or a similar
+         * method because in this case unsetting variables means restoring them to PID1 default values, which
+         * may be outdated, since locale.conf has just changed and PID1 hasn't read it */
+        (void) reload_system_manager(sd_bus_message_get_bus(m));
 
         if (!strv_isempty(l_set)) {
                 _cleanup_free_ char *line = NULL;