Merge pull request #13136 from keszybz/readd-ntp-units.d

ntp-units.d support

8 files changed, 119 insertions, 43 deletions

diff --git a/man/systemd-timedated.service.xml b/man/systemd-timedated.service.xml
index 3626e8bc51..f981848cb2 100644
--- a/man/systemd-timedated.service.xml
+++ b/man/systemd-timedated.service.xml
@@ -31,7 +31,7 @@
 
     <para><filename>systemd-timedated</filename> is a system service
     that may be used as a mechanism to change the system clock and
-    timezone, as well as to enable/disable NTP time synchronization.
+    timezone, as well as to enable/disable network time synchronization.
     <filename>systemd-timedated</filename> is automatically activated
     on request and terminates itself when it is unused.</para>
 
@@ -46,25 +46,36 @@
   </refsect1>
 
   <refsect1>
-    <title>Environment</title>
-
-    <variablelist class='environment-variables'>
-      <varlistentry>
-        <term><varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname></term>
-
-        <listitem><para>Colon-separated list of unit names of NTP client services.
-        If not set, then
-        <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-        is used. See the entries of NTP related commands of
-        <citerefentry><refentrytitle>timedatectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
-        for details about this.</para>
-
-        <para>Example:
-        <programlisting>SYSTEMD_TIMEDATED_NTP_SERVICES=ntpd.service:chronyd.service:systemd-timesyncd.service</programlisting>
-        </para></listitem>
-      </varlistentry>
-    </variablelist>
+    <title>List of network time synchronization services</title>
+
+    <para><command>systemd-timesyncd</command> will look for files with a <literal>.list</literal> extension
+    in <filename>ntp-units.d/</filename> directories. Each file is parsed as a list of unit names, one per
+    line. Empty lines and lines with comments (<literal>#</literal>) are ignored.  Files are read from
+    <filename>/usr/lib/systemd/ntp-units.d/</filename> and the corresponding directories under
+    <filename>/etc/</filename>, <filename>/run/</filename>, <filename>/usr/local/lib/</filename>. Files in
+    <filename>/etc/</filename> override files with the same name in <filename>/run/</filename>,
+    <filename>/usr/local/lib/</filename>, and <filename>/usr/lib/</filename>. Files in
+    <filename>/run/</filename> override files with the same name under <filename>/usr/</filename>. Packages
+    should install their configuration files in <filename>/usr/lib/</filename> (distribution packages) or
+    <filename>/usr/local/lib/</filename> (local installs).</para>
+
+    <example>
+      <title><filename>ntp-units.d/</filename> entry for <command>systemd-timesyncd</command></title>
+      <programlisting># /usr/lib/systemd/ntp-units.d/80-systemd-timesync.list
+systemd-timesyncd.service
+</programlisting>
+    </example>
+
+    <para>If the environment variable <varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname> is set,
+    <command>systemd-timesyncd</command> will parse the contents of that variable as a colon-separated list
+    of unit names. When set, this variable overrides the file-based list described above.</para>
+
+    <example>
+      <title>An override that specifies that <command>chronyd</command> should be used if available</title>
+      <programlisting>SYSTEMD_TIMEDATED_NTP_SERVICES=chronyd.service:systemd-timesyncd.service</programlisting>
+    </example>
   </refsect1>
+
   <refsect1>
     <title>See Also</title>
     <para>
diff --git a/man/timedatectl.xml b/man/timedatectl.xml
index 262b9126e7..f797e0cd67 100644
--- a/man/timedatectl.xml
+++ b/man/timedatectl.xml
@@ -23,22 +23,25 @@
 
   <refsynopsisdiv>
     <cmdsynopsis>
-      <command>timedatectl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
+      <command>timedatectl</command>
+      <arg choice="opt" rep="repeat">OPTIONS</arg>
+      <arg choice="req">COMMAND</arg>
     </cmdsynopsis>
   </refsynopsisdiv>
 
   <refsect1>
     <title>Description</title>
 
-    <para><command>timedatectl</command> may be used to query and
-    change the system clock and its settings.</para>
+    <para><command>timedatectl</command> may be used to query and change the system clock and its settings,
+    and enable or disable time synchronization services.</para>
 
     <para>Use
     <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
     to initialize the system time zone for mounted (but not booted)
     system images.</para>
 
-    <para><command>timedatectl</command> may be used to show the current status of
+    <para><command>timedatectl</command> may be used to show the current status of time synchronization
+    services, for example
     <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
     </para>
 
@@ -123,11 +126,8 @@
       <varlistentry>
         <term><command>status</command></term>
 
-        <listitem><para>Show current settings of the system clock and RTC,
-        including whether network time synchronization through
-        <filename>systemd-timesyncd.service</filename> is active. Even if it is
-        inactive, a different service might still synchronize the clock.
-        If no command is specified, this is the implied default.
+        <listitem><para>Show current settings of the system clock and RTC, including whether network time
+        synchronization is active. If no command is specified, this is the implied default.
         </para></listitem>
       </varlistentry>
 
@@ -193,11 +193,11 @@
       <varlistentry>
         <term><command>set-ntp [BOOL]</command></term>
 
-        <listitem><para>Takes a boolean argument. Controls whether network time synchronization is active
-        and enabled (if available). If the argument is true, this enables and starts the first existed
-        service listed in the environment variable <varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname>
-        of <filename>systemd-timedated.service</filename>. If the argument is false, then this disables and
-        stops the all services listed in <varname>$SYSTEMD_TIMEDATED_NTP_SERVICES</varname>.</para></listitem>
+        <listitem><para>Takes a boolean argument. Controls whether network time synchronization is active and
+        enabled (if available). If the argument is true, this enables and starts the first existing network
+        synchronization service. If the argument is false, then this disables and stops the known network
+        synchronization services. The way that the list of services is built is described below.</para>
+        </listitem>
       </varlistentry>
 
     </variablelist>
@@ -250,8 +250,7 @@
   <refsect1>
     <title>Exit status</title>
 
-    <para>On success, 0 is returned, a non-zero failure
-    code otherwise.</para>
+    <para>On success, 0 is returned, a non-zero failure code otherwise.</para>
   </refsect1>
 
   <xi:include href="less-variables.xml" />
diff --git a/meson.build b/meson.build
index 04a830cdfa..09abd9e2ec 100644
--- a/meson.build
+++ b/meson.build
@@ -157,6 +157,7 @@ systemdstatedir = join_paths(localstatedir, 'lib/systemd')
 catalogstatedir = join_paths(systemdstatedir, 'catalog')
 randomseeddir = join_paths(localstatedir, 'lib/systemd')
 profiledir = join_paths(rootlibexecdir, 'portable', 'profile')
+ntpservicelistdir = join_paths(rootprefixdir, 'lib/systemd/ntp-units.d')
 
 docdir = get_option('docdir')
 if docdir == ''
diff --git a/src/shared/pretty-print.c b/src/shared/pretty-print.c
index c602e036eb..96e74a758f 100644
--- a/src/shared/pretty-print.c
+++ b/src/shared/pretty-print.c
@@ -247,6 +247,11 @@ static int guess_type(const char **name, bool *is_usr, bool *is_collection, cons
         if (path_equal(n, "kernel/install.d"))
                 ext = ".install";
 
+        if (path_equal(n, "systemd/ntp-units.d")) {
+                coll = true;
+                ext = ".list";
+        }
+
         if (PATH_IN_SET(n, "systemd/system-preset", "systemd/user-preset")) {
                 coll = true;
                 ext = ".preset";
diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
index 57bbefc0c1..074ba3c079 100644
--- a/src/timedate/timedated.c
+++ b/src/timedate/timedated.c
@@ -15,7 +15,9 @@
 #include "bus-error.h"
 #include "bus-util.h"
 #include "clock-util.h"
+#include "conf-files.h"
 #include "def.h"
+#include "fd-util.h"
 #include "fileio-label.h"
 #include "fileio.h"
 #include "fs-util.h"
@@ -36,6 +38,8 @@
 #define NULL_ADJTIME_UTC "0.0 0 0\n0\nUTC\n"
 #define NULL_ADJTIME_LOCAL "0.0 0 0\n0\nLOCAL\n"
 
+#define UNIT_LIST_DIRS (const char* const*) CONF_PATHS_STRV("systemd/ntp-units.d")
+
 typedef struct UnitStatusInfo {
         char *name;
         char *load_state;
@@ -117,20 +121,17 @@ static int context_add_ntp_service(Context *c, const char *s) {
         return 0;
 }
 
-static int context_parse_ntp_services(Context *c) {
+static int context_parse_ntp_services_from_environment(Context *c) {
         const char *env, *p;
         int r;
 
         assert(c);
 
         env = getenv("SYSTEMD_TIMEDATED_NTP_SERVICES");
-        if (!env) {
-                r = context_add_ntp_service(c, "systemd-timesyncd.service");
-                if (r < 0)
-                        log_warning_errno(r, "Failed to add NTP service \"systemd-timesyncd.service\", ignoring: %m");
-
+        if (!env)
                 return 0;
-        }
+
+        log_debug("Using list of ntp services from environment variable $SYSTEMD_TIMEDATED_NTP_SERVICES.");
 
         for (p = env;;) {
                 _cleanup_free_ char *word = NULL;
@@ -150,7 +151,62 @@ static int context_parse_ntp_services(Context *c) {
                         log_warning_errno(r, "Failed to add NTP service \"%s\", ignoring: %m", word);
         }
 
-        return 0;
+        return 1;
+}
+
+static int context_parse_ntp_services_from_disk(Context *c) {
+        _cleanup_strv_free_ char **files = NULL;
+        char **f;
+        int r;
+
+        r = conf_files_list_strv(&files, ".list", NULL, CONF_FILES_FILTER_MASKED, UNIT_LIST_DIRS);
+        if (r < 0)
+                return log_error_errno(r, "Failed to enumerate .list files: %m");
+
+        STRV_FOREACH(f, files) {
+                _cleanup_fclose_ FILE *file = NULL;
+
+                log_debug("Reading file '%s'", *f);
+
+                r = fopen_unlocked(*f, "re", &file);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to open %s, ignoring: %m", *f);
+                        continue;
+                }
+
+                for (;;) {
+                        _cleanup_free_ char *line = NULL;
+                        const char *word;
+
+                        r = read_line(file, LINE_MAX, &line);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to read %s, ignoring: %m", *f);
+                                continue;
+                        }
+                        if (r == 0)
+                                break;
+
+                        word = strstrip(line);
+                        if (isempty(word) || startswith("#", word))
+                                continue;
+
+                        r = context_add_ntp_service(c, word);
+                        if (r < 0)
+                                log_warning_errno(r, "Failed to add NTP service \"%s\", ignoring: %m", word);
+                }
+        }
+
+        return 1;
+}
+
+static int context_parse_ntp_services(Context *c) {
+        int r;
+
+        r = context_parse_ntp_services_from_environment(c);
+        if (r != 0)
+                return r;
+
+        return context_parse_ntp_services_from_disk(c);
 }
 
 static int context_ntp_service_is_active(Context *c) {
diff --git a/src/timesync/80-systemd-timesync.list b/src/timesync/80-systemd-timesync.list
new file mode 100644
index 0000000000..d5959ade89
--- /dev/null
+++ b/src/timesync/80-systemd-timesync.list
@@ -0,0 +1 @@
+systemd-timesyncd.service
diff --git a/src/timesync/meson.build b/src/timesync/meson.build
index b79ef08277..e5c118c8db 100644
--- a/src/timesync/meson.build
+++ b/src/timesync/meson.build
@@ -32,6 +32,8 @@ if conf.get('ENABLE_TIMESYNCD') == 1
                      install_dir : dbuspolicydir)
         install_data('org.freedesktop.timesync1.service',
                      install_dir : dbussystemservicedir)
+        install_data('80-systemd-timesync.list',
+                     install_dir : ntpservicelistdir)
 endif
 
 ############################################################
diff --git a/units/systemd-timesyncd.service.in b/units/systemd-timesyncd.service.in
index 2d8d14f6de..2136a85b35 100644
--- a/units/systemd-timesyncd.service.in
+++ b/units/systemd-timesyncd.service.in
@@ -15,6 +15,7 @@ ConditionVirtualization=!container
 DefaultDependencies=no
 After=systemd-remount-fs.service systemd-sysusers.service
 Before=time-set.target sysinit.target shutdown.target
+Conflicts=chronyd.service ntpd.service
 Conflicts=shutdown.target
 Wants=time-set.target time-sync.target