units: add time-set.target

time-sync.target is supposed to indicate system clock is synchronized
with a remote clock, but as used through 241 it only provided a system
clock that was updated based on a locally-maintained timestamp.  Systems
that are powered off for extended periods would not come up with
accurate time.

Retain the existing behavior using a new time-set.target leaving
time-sync.target for cases where accuracy is required.

Closes #8861

1 files changed, 13 insertions, 0 deletions

diff --git a/man/systemd.special.xml b/man/systemd.special.xml
index b7df5016ce..248fb924db 100644
--- a/man/systemd.special.xml
+++ b/man/systemd.special.xml
@@ -77,6 +77,7 @@
     <filename>sysinit.target</filename>,
     <filename>system-update.target</filename>,
     <filename>system-update-pre.target</filename>,
+    <filename>time-set.target</filename>,
     <filename>time-sync.target</filename>,
     <filename>timers.target</filename>,
     <filename>umount.target</filename>,
@@ -951,6 +952,18 @@
           </listitem>
         </varlistentry>
         <varlistentry>
+          <term><filename>time-set.target</filename></term>
+          <listitem>
+            <para>Services responsible for setting the system clock from
+            a local source (such as a maintained timestamp file or
+            imprecise real-time clock) should pull in this target and
+            order themselves before it.  Services where approximate time
+            is desired should be ordered after this unit, but not pull
+            it in.  This target does not provide the accuracy guarantees
+            of <filename>time-sync.target</filename>.</para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
           <term><filename>time-sync.target</filename></term>
           <listitem>
             <para>Services responsible for synchronizing the system