firstboot: permit setting the static hostname via a system credential

For the IMDS case there's value in being able to set the static
hostname, instead of just the transient one. Let's introduce
firstboot.hostname, which only applies to first boot, and write the
static hostname. This is different from system.hostname which applies to
any boot, and writes the transient hostname.

diff --git a/man/systemd-firstboot.xml b/man/systemd-firstboot.xml
index 86a85f0bf2855bd7673bae9d16dc86c7df533cef..db6f2569a8d1f859ebc76cf62c3f8a6f6be0b3fe 100644 (file)
--- a/man/systemd-firstboot.xml
+++ b/man/systemd-firstboot.xml
@@ -447,6 +447,17 @@
 
         <xi:include href="version-info.xml" xpointer="v249"/></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>firstboot.hostname</varname></term>
+
+        <listitem><para>This credential specifies the static system hostname to set during first boot. The
+        user will not be prompted for the hostname. Note that this controls the static hostname, not the
+        transient hostname, and only has an effect on first boot, unlike
+        <varname>system.hostname</varname>.</para>
+
+        <xi:include href="version-info.xml" xpointer="v261"/></listitem>
+      </varlistentry>
     </variablelist>
 
     <para>Note that by default the <filename>systemd-firstboot.service</filename> unit file is set up to

diff --git a/man/systemd.system-credentials.xml b/man/systemd.system-credentials.xml
index e3e2887207784f25d9f2fbbe41d52d5901fc87cb..a302be236d40d9274d30ed64b2eda508bad0f4a7 100644 (file)
--- a/man/systemd.system-credentials.xml
+++ b/man/systemd.system-credentials.xml
@@ -44,7 +44,7 @@
       <varlistentry>
         <term><varname>firstboot.keymap</varname></term>
         <listitem>
-          <para>The console key mapping to set (e.g. <literal>de</literal>).  Read by
+          <para>The console key mapping to set (e.g. <literal>de</literal>). Read by
           <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
           and only honoured if no console keymap has been configured before.</para>
 
@@ -52,6 +52,20 @@
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>firstboot.hostname</varname></term>
+
+        <listitem><para>This credential specifies the static system hostname to set during first boot. The
+        user will not be prompted for the hostname. Note that this controls the static hostname, not the transient
+        hostname, and only has an effect on first boot, unlike <varname>system.hostname</varname> (see
+        below). Read by
+        <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+        and only honoured if no static hostname has been configured before.</para>
+
+        <xi:include href="version-info.xml" xpointer="v261"/>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>firstboot.locale</varname></term>
         <term><varname>firstboot.locale-messages</varname></term>
@@ -398,9 +412,10 @@
         <term><varname>system.hostname</varname></term>
         <listitem>
           <para>Accepts a (transient) hostname to configure during early boot. The static hostname specified
-            in <filename>/etc/hostname</filename>, if configured, takes precedence over this setting.
-            Interpreted by the service manager (PID 1). For details see
-            <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
+          in <filename>/etc/hostname</filename>, if configured, takes precedence over this setting.
+          Interpreted by the service manager (PID 1). For details see
+          <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Also
+          see <varname>firstboot.hostname</varname> above.</para>
 
           <xi:include href="version-info.xml" xpointer="v254"/>
         </listitem>

diff --git a/src/firstboot/firstboot.c b/src/firstboot/firstboot.c
index ae1899593cdd9ff1d6cebeb6c215915257a7b1b0..8cb81e7f06e700cdf5353efa09efcb6fd26c4168 100644 (file)
--- a/src/firstboot/firstboot.c
+++ b/src/firstboot/firstboot.c
@@ -655,6 +655,19 @@ static int prompt_hostname(int rfd, sd_varlink **mute_console_link) {
         if (arg_hostname)
                 return 0;
 
+        _cleanup_free_ char *hn = NULL;
+        r = read_credential("firstboot.hostname", (void**) &hn, NULL);
+        if (r < 0)
+                log_debug_errno(r, "Failed to read credential firstboot.hostname, ignoring: %m");
+        else if (!hostname_is_valid(hn, VALID_HOSTNAME_TRAILING_DOT|VALID_HOSTNAME_QUESTION_MARK))
+                log_warning_errno(SYNTHETIC_ERRNO(EINVAL), "Hostname '%s' supplied via credential is not valid, ignoring.", hn);
+        else {
+                log_debug("Acquired hostname from credentials.");
+                arg_hostname = TAKE_PTR(hn);
+                hostname_cleanup(arg_hostname);
+                return 0;
+        }
+
         if (!arg_prompt_hostname) {
                 log_debug("Prompting for hostname was not requested.");
                 return 0;