report: turn systemd-report itself into a varlink service

Add a Varlink API for requesting a report.

src/shared/meson.build

@@ -241,6 +241,7 @@ shared_sources = files(
         'varlink-io.systemd.PCRExtend.c',
         'varlink-io.systemd.PCRLock.c',
         'varlink-io.systemd.Repart.c',
+        'varlink-io.systemd.Report.c',
         'varlink-io.systemd.Report.Signer.c',
         'varlink-io.systemd.Report.Uploader.c',
         'varlink-io.systemd.Resolve.c',

src/shared/varlink-io.systemd.Report.c

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "varlink-io.systemd.Report.h"
+
+static SD_VARLINK_DEFINE_METHOD(
+                Generate,
+                SD_VARLINK_FIELD_COMMENT("Selects which metrics to include in the report, as an array of metric family names or prefixes thereof. If unset or empty all available metrics are included. This matches the [MATCH…] arguments of the systemd-report command line tool."),
+                SD_VARLINK_DEFINE_INPUT(matches, SD_VARLINK_STRING, SD_VARLINK_ARRAY|SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The generated report as a JSON object. This mode does not sign the report, hence a precise binary formatting of the JSON data is not relevant."),
+                SD_VARLINK_DEFINE_OUTPUT(report, SD_VARLINK_OBJECT, 0));
+
+static SD_VARLINK_DEFINE_METHOD(
+                GenerateSigned,
+                SD_VARLINK_FIELD_COMMENT("Selects which metrics to include in the report, as an array of metric family names or prefixes thereof. If unset or empty all available metrics are included. This matches the [MATCH…] arguments of the systemd-report command line tool."),
+                SD_VARLINK_DEFINE_INPUT(matches, SD_VARLINK_STRING, SD_VARLINK_ARRAY|SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The generated, signed report in Base64. A precise binary formatting of the JSON data is important to authenticate the signature. This data contains a JSON-SEQ compliant stream of objects, the first being the report, the following ones signature objects."),
+                SD_VARLINK_DEFINE_OUTPUT(reportData, SD_VARLINK_STRING, 0));
+
+SD_VARLINK_DEFINE_INTERFACE(
+                io_systemd_Report,
+                "io.systemd.Report",
+                SD_VARLINK_INTERFACE_COMMENT("Frontend API for generating system reports. This interface is implemented by systemd-report, which aggregates the metrics exposed by the io.systemd.Metrics services linked into /run/systemd/report/."),
+                SD_VARLINK_SYMBOL_COMMENT("Generate a report and return it as a JSON object."),
+                &vl_method_Generate,
+                SD_VARLINK_SYMBOL_COMMENT("Generate a signed report and return it Base64 encoded."),
+                &vl_method_GenerateSigned);

src/shared/varlink-io.systemd.Report.h

@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-varlink-idl.h"
+
+extern const sd_varlink_interface vl_interface_io_systemd_Report;