From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Gabriel Ebner <gebner@gebner.org>
Date: Sun, 6 Dec 2015 14:26:36 +0100
Subject: [PATCH] hostnamed, localed, timedated: disable methods that change
 system settings.

---
 src/hostname/hostnamed.c |  6 ++++++
 src/locale/localed.c     |  9 +++++++++
 src/timedate/timedated.c | 10 ++++++++++
 3 files changed, 25 insertions(+)

diff --git a/src/hostname/hostnamed.c b/src/hostname/hostnamed.c
index 9ef45f8e75..99b1ec2e36 100644
--- a/src/hostname/hostnamed.c
+++ b/src/hostname/hostnamed.c
@@ -1053,6 +1053,9 @@ static int method_set_static_hostname(sd_bus_message *m, void *userdata, sd_bus_
         if (r < 0)
                 return r;
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         name = empty_to_null(name);
 
         context_read_etc_hostname(c);
@@ -1116,6 +1119,9 @@ static int set_machine_info(Context *c, sd_bus_message *m, int prop, sd_bus_mess
         if (r < 0)
                 return r;
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         name = empty_to_null(name);
 
         context_read_machine_info(c);
diff --git a/src/locale/localed.c b/src/locale/localed.c
index f544a73580..ce00c262cc 100644
--- a/src/locale/localed.c
+++ b/src/locale/localed.c
@@ -229,6 +229,9 @@ static int method_set_locale(sd_bus_message *m, void *userdata, sd_bus_error *er
 
         use_localegen = locale_gen_check_available();
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         /* If single locale without variable name is provided, then we assume it is LANG=. */
         if (strv_length(l) == 1 && !strchr(l[0], '=')) {
                 if (!locale_is_valid(l[0]))
@@ -347,6 +350,9 @@ static int method_set_vc_keyboard(sd_bus_message *m, void *userdata, sd_bus_erro
         if (r < 0)
                 return bus_log_parse_error(r);
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         vc_context_empty_to_null(&in);
 
         r = vc_context_verify_and_warn(&in, LOG_ERR, error);
@@ -465,6 +471,9 @@ static int method_set_x11_keyboard(sd_bus_message *m, void *userdata, sd_bus_err
         if (r < 0)
                 return bus_log_parse_error(r);
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         x11_context_empty_to_null(&in);
 
         r = x11_context_verify_and_warn(&in, LOG_ERR, error);
diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
index ad1d492d6b..331af34505 100644
--- a/src/timedate/timedated.c
+++ b/src/timedate/timedated.c
@@ -665,6 +665,10 @@ static int method_set_timezone(sd_bus_message *m, void *userdata, sd_bus_error *
         if (r < 0)
                 return r;
 
+        if (getenv("NIXOS_STATIC_TIMEZONE"))
+                return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+                    "Changing timezone via systemd is not supported when it is set in NixOS configuration.");
+
         if (!timezone_is_valid(z, LOG_DEBUG))
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid or not installed time zone '%s'", z);
 
@@ -743,6 +747,9 @@ static int method_set_local_rtc(sd_bus_message *m, void *userdata, sd_bus_error
         if (r < 0)
                 return r;
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         if (lrtc == c->local_rtc && !fix_system)
                 return sd_bus_reply_method_return(m, NULL);
 
@@ -923,6 +930,9 @@ static int method_set_ntp(sd_bus_message *m, void *userdata, sd_bus_error *error
         if (r < 0)
                 return r;
 
+        return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED,
+            "Changing system settings via systemd is not supported on NixOS.");
+
         r = context_update_ntp_status(c, bus, m);
         if (r < 0)
                 return r;