systemd: add --version option

systemd --version mirrors systemctl --version:

$ ./systemd --version
systemd 186
other
+PAM +LIBWRAP +AUDIT +SELINUX +IMA +SYSVINIT -LIBCRYPTSETUP

This information can be retrieved by other means (systemctl, etc.),
but it's easier for a newbie if 'systemd --version' says something
useful. And 'systemd --help' is already there, so let's complement
that with '--version'.

2 files changed, 24 insertions, 0 deletions

diff --git a/man/systemd.xml b/man/systemd.xml
index c598a896f0..dc89ee7eab 100644
--- a/man/systemd.xml
+++ b/man/systemd.xml
@@ -96,6 +96,12 @@
                                 text and exits.</para></listitem>
                         </varlistentry>
                         <varlistentry>
+                                <term><option>--version</option></term>
+
+                                <listitem><para>Prints a systemd version
+                                identifier and exits.</para></listitem>
+                        </varlistentry>
+                        <varlistentry>
                                 <term><option>--test</option></term>
 
                                 <listitem><para>Determine startup
diff --git a/src/core/main.c b/src/core/main.c
index ae3769be52..f1f8b21ae0 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -66,6 +66,7 @@
 static enum {
         ACTION_RUN,
         ACTION_HELP,
+        ACTION_VERSION,
         ACTION_TEST,
         ACTION_DUMP_CONFIGURATION_ITEMS,
         ACTION_DONE
@@ -750,6 +751,7 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_SYSTEM,
                 ARG_USER,
                 ARG_TEST,
+                ARG_VERSION,
                 ARG_DUMP_CONFIGURATION_ITEMS,
                 ARG_DUMP_CORE,
                 ARG_CRASH_SHELL,
@@ -772,6 +774,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "user",                     no_argument,       NULL, ARG_USER                     },
                 { "test",                     no_argument,       NULL, ARG_TEST                     },
                 { "help",                     no_argument,       NULL, 'h'                          },
+                { "version",                  no_argument,       NULL, ARG_VERSION                  },
                 { "dump-configuration-items", no_argument,       NULL, ARG_DUMP_CONFIGURATION_ITEMS },
                 { "dump-core",                optional_argument, NULL, ARG_DUMP_CORE                },
                 { "crash-shell",              optional_argument, NULL, ARG_CRASH_SHELL              },
@@ -877,6 +880,10 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_action = ACTION_TEST;
                         break;
 
+                case ARG_VERSION:
+                        arg_action = ACTION_VERSION;
+                        break;
+
                 case ARG_DUMP_CONFIGURATION_ITEMS:
                         arg_action = ACTION_DUMP_CONFIGURATION_ITEMS;
                         break;
@@ -1043,6 +1050,14 @@ static int help(void) {
         return 0;
 }
 
+static int version(void) {
+        puts(PACKAGE_STRING);
+        puts(DISTRIBUTION);
+        puts(SYSTEMD_FEATURES);
+
+        return 0;
+}
+
 static int prepare_reexecute(Manager *m, FILE **_f, FDSet **_fds) {
         FILE *f = NULL;
         FDSet *fds = NULL;
@@ -1328,6 +1343,9 @@ int main(int argc, char *argv[]) {
         if (arg_action == ACTION_HELP) {
                 retval = help();
                 goto finish;
+        } else if (arg_action == ACTION_VERSION) {
+                retval = version();
+                goto finish;
         } else if (arg_action == ACTION_DUMP_CONFIGURATION_ITEMS) {
                 unit_dump_config_items(stdout);
                 retval = EXIT_SUCCESS;