report-sign-plain: convert to VERB_COMMAND and add --introspect-cli

The custom help() is replaced by a COMMAND() description, and
--introspect-cli is added.

src/report/report-sign-plain.c

@@ -13,21 +13,25 @@
 #include "errno-util.h"
 #include "fd-util.h"
 #include "fileio.h"
-#include "format-table.h"
 #include "fs-util.h"
-#include "help-util.h"
 #include "iovec-util.h"
 #include "json-util.h"
 #include "lock-util.h"
 #include "log.h"
 #include "main-func.h"
 #include "metrics.h"
-#include "options.h"
 #include "stat-util.h"
 #include "tmpfile-util.h"
 #include "varlink-io.systemd.Metrics.h"
 #include "varlink-io.systemd.Report.Signer.h"
 #include "varlink-util.h"
+#include "verbs.h"
+
+COMMAND(
+        "systemd-report-sign-plain\0",
+        "Sign system reports with a local software key.",
+        .man_pages = "systemd-report-sign-plain@.service.8\0",
+);
 
 #define REPORT_SIGN_PLAIN_DIR         "/var/lib/systemd/report.sign.plain"
 #define REPORT_SIGN_PLAIN_PRIVATE_KEY "local.private"
@@ -339,26 +343,6 @@ static int vl_server(void) {
         return 0;
 }
 
-static int help(void) {
-        _cleanup_(table_unrefp) Table *options = NULL;
-        int r;
-
-        r = option_parser_get_help_table(&options);
-        if (r < 0)
-                return r;
-
-        help_cmdline("[OPTIONS...]");
-        help_abstract("Sign system reports with a local software key.");
-        help_section("Options");
-
-        r = table_print_or_warn(options);
-        if (r < 0)
-                return r;
-
-        help_man_page_reference("systemd-report-sign-plain@.service", "8");
-        return 0;
-}
-
 static int parse_argv(int argc, char *argv[]) {
         int r;
 
@@ -370,10 +354,13 @@ static int parse_argv(int argc, char *argv[]) {
         FOREACH_OPTION_OR_RETURN(c, &opts)
                 switch (c) {
                 OPTION_COMMON_HELP:
-                        return help();
+                        return command_print_help("systemd-report-sign-plain");
 
                 OPTION_COMMON_VERSION:
                         return version();
+
+                OPTION_COMMON_INTROSPECT_CLI:
+                        return introspect_cli(SD_JSON_FORMAT_OFF);
                 }
 
         if (option_parser_get_n_args(&opts) > 0)

test/units/TEST-74-AUX-UTILS.introspect-cli.sh

@@ -91,6 +91,7 @@ INTROSPECTABLE=(
     systemd-report-basic
     systemd-report-cgroup
     systemd-report-files
+    systemd-report-sign-plain
     systemd-run
     systemd-sbsign
     systemd-sleep