Merge pull request #15473 from keszybz/bus-introspection

src/shared/bus-log-control-api.c

@@ -107,17 +107,8 @@ static const sd_bus_vtable log_control_vtable[] = {
         SD_BUS_VTABLE_END,
 };
 
-int bus_log_control_api_register(sd_bus *bus) {
-        int r;
-
-        r = sd_bus_add_object_vtable(
-                        bus,
-                        NULL,
-                        "/org/freedesktop/LogControl1",
-                        "org.freedesktop.LogControl1",
-                        log_control_vtable, NULL);
-        if (r < 0)
-                return log_error_errno(r, "Failed to register service API object: %m");
-
-        return 0;
-}
+const BusObjectImplementation log_control_object = {
+        "/org/freedesktop/LogControl1",
+        "org.freedesktop.LogControl1",
+        .vtables = BUS_VTABLES(log_control_vtable),
+};

src/shared/bus-log-control-api.h

@@ -2,7 +2,12 @@
 
 #include "sd-bus.h"
 
-int bus_log_control_api_register(sd_bus *bus);
+#include "bus-util.h"
+
+extern const BusObjectImplementation log_control_object;
+static inline int bus_log_control_api_register(sd_bus *bus) {
+        return bus_add_implementation(bus, &log_control_object, NULL);
+}
 
 int bus_property_get_log_level(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error);
 int bus_property_set_log_level(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, void *userdata, sd_bus_error *error);

src/shared/bus-util.c

@@ -16,6 +16,7 @@
 
 #include "alloc-util.h"
 #include "bus-internal.h"
+#include "bus-introspect.h"
 #include "bus-label.h"
 #include "bus-message.h"
 #include "bus-util.h"
@@ -1549,3 +1550,171 @@ int bus_message_new_method_call(
 
         return sd_bus_message_new_method_call(bus, m, locator->destination, locator->path, locator->interface, member);
 }
+
+int bus_add_implementation(sd_bus *bus, const BusObjectImplementation *impl, void *userdata) {
+        int r;
+
+        log_debug("Registering bus object implementation for path=%s iface=%s", impl->path, impl->interface);
+
+        for (const sd_bus_vtable **p = impl->vtables; p && *p; p++) {
+                r = sd_bus_add_object_vtable(bus, NULL,
+                                             impl->path,
+                                             impl->interface,
+                                             *p,
+                                             userdata);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to register bus path %s with interface %s: %m",
+                                               impl->path,
+                                               impl->interface);
+        }
+
+        for (const BusObjectVtablePair *p = impl->fallback_vtables; p && p->vtable; p++) {
+                r = sd_bus_add_fallback_vtable(bus, NULL,
+                                               impl->path,
+                                               impl->interface,
+                                               p->vtable,
+                                               p->object_find,
+                                               userdata);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to register bus path %s with interface %s: %m",
+                                               impl->path,
+                                               impl->interface);
+        }
+
+        if (impl->node_enumerator) {
+                r = sd_bus_add_node_enumerator(bus, NULL,
+                                               impl->path,
+                                               impl->node_enumerator,
+                                               userdata);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to add node enumerator for %s: %m",
+                                               impl->path);
+        }
+
+        for (size_t i = 0; impl->children && impl->children[i]; i++) {
+                r = bus_add_implementation(bus, impl->children[i], userdata);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static const BusObjectImplementation* find_implementation(
+                const char *pattern,
+                const BusObjectImplementation* const* bus_objects) {
+
+        for (size_t i = 0; bus_objects && bus_objects[i]; i++) {
+                const BusObjectImplementation *impl = bus_objects[i];
+
+                if (STR_IN_SET(pattern, impl->path, impl->interface))
+                        return impl;
+
+                impl = find_implementation(pattern, impl->children);
+                if (impl)
+                        return impl;
+        }
+
+        return NULL;
+}
+
+static int bus_introspect_implementation(
+                struct introspect *intro,
+                const BusObjectImplementation *impl) {
+        int r;
+
+        for (const sd_bus_vtable **p = impl->vtables; p && *p; p++) {
+                r = introspect_write_interface(intro, impl->interface, *p);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to write introspection data: %m");
+        }
+
+        for (const BusObjectVtablePair *p = impl->fallback_vtables; p && p->vtable; p++) {
+                r = introspect_write_interface(intro, impl->interface, p->vtable);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to write introspection data: %m");
+        }
+
+        return 0;
+}
+
+static void list_paths(
+                FILE *out,
+                const BusObjectImplementation* const* bus_objects) {
+
+        for (size_t i = 0; bus_objects[i]; i++) {
+                fprintf(out, "%s\t%s\n", bus_objects[i]->path, bus_objects[i]->interface);
+                if (bus_objects[i]->children)
+                        list_paths(out, bus_objects[i]->children);
+        }
+}
+
+int bus_introspect_implementations(
+                FILE *out,
+                const char *pattern,
+                const BusObjectImplementation* const* bus_objects) {
+
+        const BusObjectImplementation *impl, *main_impl = NULL;
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        if (streq(pattern, "list")) {
+                list_paths(out, bus_objects);
+                return 0;
+        }
+
+        struct introspect intro = {};
+        bool is_interface = interface_name_is_valid(pattern);
+
+        impl = find_implementation(pattern, bus_objects);
+        if (!impl)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOENT),
+                                       "%s %s not found",
+                                       is_interface ? "Interface" : "Object path",
+                                       pattern);
+
+        /* We use trusted=false here to get all the @org.freedesktop.systemd1.Privileged annotations. */
+        r = introspect_begin(&intro, false);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write introspection data: %m");
+
+        r = introspect_write_default_interfaces(&intro, impl->manager);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write introspection data: %m");
+
+        /* Check if there is a non-fallback path that applies to the given interface, also
+         * print it. This is useful in the case of units: o.fd.systemd1.Service is declared
+         * as a fallback vtable for o/fd/systemd1/unit, and we also want to print
+         * o.fd.systemd1.Unit, which is the non-fallback implementation. */
+        if (impl->fallback_vtables && is_interface)
+                main_impl = find_implementation(impl->path, bus_objects);
+
+        if (main_impl)
+                bus_introspect_implementation(&intro, main_impl);
+
+        if (impl != main_impl)
+                bus_introspect_implementation(&intro, impl);
+
+        _cleanup_set_free_free_ Set *nodes = NULL;
+
+        for (size_t i = 0; impl->children && impl->children[i]; i++) {
+                r = set_ensure_allocated(&nodes, &string_hash_ops);
+                if (r < 0)
+                        return log_oom();
+
+                r = set_put_strdup(nodes, impl->children[i]->path);
+                if (r < 0)
+                        return log_oom();
+        }
+
+        r = introspect_write_child_nodes(&intro, nodes, impl->path);
+        if (r < 0)
+                return r;
+
+        r = introspect_finish(&intro, &s);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write introspection data: %m");
+
+        fputs(s, out);
+        return 0;
+}

src/shared/bus-util.h

@@ -23,11 +23,32 @@ typedef enum BusTransport {
 } BusTransport;
 
 typedef struct BusLocator {
-        const char    *destination;
-        const char    *path;
-        const char    *interface;
+        const char *destination;
+        const char *path;
+        const char *interface;
 } BusLocator;
 
+typedef struct BusObjectImplementation BusObjectImplementation;
+
+typedef struct BusObjectVtablePair {
+        const sd_bus_vtable *vtable;
+        sd_bus_object_find_t object_find;
+} BusObjectVtablePair;
+
+struct BusObjectImplementation {
+        const char *path;
+        const char *interface;
+        const sd_bus_vtable **vtables;
+        const BusObjectVtablePair *fallback_vtables;
+        sd_bus_node_enumerator_t node_enumerator;
+        bool manager;
+        const BusObjectImplementation **children;
+};
+
+#define BUS_VTABLES(...) ((const sd_bus_vtable* []){ __VA_ARGS__, NULL })
+#define BUS_FALLBACK_VTABLES(...) ((const BusObjectVtablePair[]) { __VA_ARGS__, {} })
+#define BUS_IMPLEMENTATIONS(...) ((const BusObjectImplementation* []) { __VA_ARGS__, NULL })
+
 typedef int (*bus_property_set_t) (sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata);
 
 struct bus_properties_map {
@@ -199,3 +220,9 @@ int bus_set_property(sd_bus *bus, const BusLocator *locator, const char *member,
 int bus_match_signal(sd_bus *bus, sd_bus_slot **ret, const BusLocator *locator, const char *member, sd_bus_message_handler_t callback, void *userdata);
 int bus_match_signal_async(sd_bus *bus, sd_bus_slot **ret, const BusLocator *locator, const char *member, sd_bus_message_handler_t callback, sd_bus_message_handler_t install_callback, void *userdata);
 int bus_message_new_method_call(sd_bus *bus, sd_bus_message **m, const BusLocator *locator, const char *member);
+
+int bus_add_implementation(sd_bus *bus, const BusObjectImplementation *impl, void *userdata);
+int bus_introspect_implementations(
+                FILE *out,
+                const char *pattern,
+                const BusObjectImplementation* const* bus_objects);

src/shared/meson.build

@@ -184,6 +184,8 @@ shared_sources = files('''
         securebits-util.h
         serialize.c
         serialize.h
+        service-util.c
+        service-util.h
         sleep-config.c
         sleep-config.h
         socket-netlink.c

src/shared/service-util.c

@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <getopt.h>
+#include <stdio.h>
+
+#include "alloc-util.h"
+#include "pretty-print.h"
+#include "service-util.h"
+#include "terminal-util.h"
+#include "util.h"
+
+static int help(const char *program_path, const char *service, const char *description, bool bus_introspect) {
+        _cleanup_free_ char *link = NULL;
+        int r;
+
+        r = terminal_urlify_man(service, "8", &link);
+        if (r < 0)
+                return log_oom();
+
+        printf("%s [OPTIONS...]\n\n"
+               "%s%s%s\n\n"
+               "This program takes no positional arguments.\n\n"
+               "%sOptions%s:\n"
+               "  -h --help                 Show this help\n"
+               "     --version              Show package version\n"
+               "     --bus-introspect=PATH  Write D-Bus XML introspection data\n"
+               "\nSee the %s for details.\n"
+               , program_path
+               , ansi_highlight(), description, ansi_normal()
+               , ansi_underline(), ansi_normal()
+               , link
+        );
+
+        return 0; /* No further action */
+}
+
+int service_parse_argv(
+                const char *service,
+                const char *description,
+                const BusObjectImplementation* const* bus_objects,
+                int argc, char *argv[]) {
+
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_BUS_INTROSPECT,
+        };
+
+        static const struct option options[] = {
+                { "help",           no_argument,       NULL, 'h'                },
+                { "version",        no_argument,       NULL, ARG_VERSION        },
+                { "bus-introspect", required_argument, NULL, ARG_BUS_INTROSPECT },
+                {}
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+                switch(c) {
+
+                case 'h':
+                        return help(argv[0], service, description, bus_objects);
+
+                case ARG_VERSION:
+                        return version();
+
+                case ARG_BUS_INTROSPECT:
+                        return bus_introspect_implementations(
+                                        stdout,
+                                        optarg,
+                                        bus_objects);
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unknown option code.");
+                }
+
+        if (optind < argc)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "This program takes no arguments.");
+
+        return 1; /* Further action */
+}

src/shared/service-util.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include "bus-util.h"
+
+int service_parse_argv(
+                const char *service,
+                const char *description,
+                const BusObjectImplementation* const* bus_objects,
+                int argc, char *argv[]);