nspawn: Set LANG to C.UTF-8

Let's default to a UTF-8 locale when running commands using nspawn.

man/systemd-fstab-generator.xml

@@ -171,6 +171,18 @@
         initrd.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>roothash=</varname></term>
+        <term><varname>usrhash=</varname></term>
+
+        <listitem><para>These options are primarily read by
+        <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>. When
+        set this indicates that the root file system (or <filename>/usr/</filename>) shall be mounted from
+        Verity volumes with the specified hashes. If these kernel command line options are set the root (or
+        <filename>/usr/</filename>) file system is thus mounted from a device mapper volume
+        <filename>/dev/mapper/root</filename> (or <filename>/dev/mapper/usr</filename>).</para></listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>systemd.volatile=</varname></term>
 

src/nspawn/nspawn.c

@@ -3218,6 +3218,7 @@ static int inner_child(
                 NULL, /* LISTEN_PID */
                 NULL, /* NOTIFY_SOCKET */
                 NULL, /* CREDENTIALS_DIRECTORY */
+                NULL, /* LANG */
                 NULL
         };
         const char *exec_target;
@@ -3486,6 +3487,16 @@ static int inner_child(
                 n_env++;
         }
 
+        if (arg_start_mode != START_BOOT) {
+                /* If we're running a command in the container, let's default to the C.UTF-8 locale as it's
+                 * part of glibc these days and was backported to most distros a long time before it got
+                 * added to upstream glibc. */
+                envp[n_env] = strdup("LANG=C.UTF-8");
+                if (!envp[n_env])
+                        return log_oom();
+                n_env++;
+        }
+
         env_use = strv_env_merge(envp, os_release_pairs, arg_setenv);
         if (!env_use)
                 return log_oom();

src/shared/install.c

@@ -2799,7 +2799,7 @@ static int normalize_linked_files(
          * but operates on real unit names. For each argument we we look up the actual path
          * where the unit is found. This way linked units can be re-enabled successfully. */
 
-        _cleanup_free_ char **files = NULL, **names = NULL;
+        _cleanup_strv_free_ char **files = NULL, **names = NULL;
         int r;
 
         STRV_FOREACH(a, names_or_paths) {