busctl: split out introspection parser from tree logic so that we can reuse it for a future "busctl introspect" command

3 files changed, 705 insertions, 567 deletions

diff --git a/src/libsystemd/sd-bus/busctl-introspect.c b/src/libsystemd/sd-bus/busctl-introspect.c
new file mode 100644
index 0000000000..041702864b
--- /dev/null
+++ b/src/libsystemd/sd-bus/busctl-introspect.c
@@ -0,0 +1,655 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "util.h"
+#include "xml.h"
+#include "sd-bus-vtable.h"
+
+#include "busctl-introspect.h"
+
+#define NODE_DEPTH_MAX 16
+
+typedef struct Context {
+        const XMLIntrospectOps *ops;
+        void *userdata;
+
+        char *interface_name;
+        uint64_t interface_flags;
+
+        char *member_name;
+        char *member_signature;
+        char *member_result;
+        uint64_t member_flags;
+
+        const char *current;
+        void *xml_state;
+} Context;
+
+static int parse_xml_annotation(Context *context, uint64_t *flags) {
+
+        enum {
+                STATE_ANNOTATION,
+                STATE_NAME,
+                STATE_VALUE
+        } state = STATE_ANNOTATION;
+
+        _cleanup_free_ char *field = NULL, *value = NULL;
+
+        assert(context);
+
+        for (;;) {
+                _cleanup_free_ char *name = NULL;
+
+                int t;
+
+                t = xml_tokenize(&context->current, &name, &context->xml_state, NULL);
+                if (t < 0) {
+                        log_error("XML parse error.");
+                        return t;
+                }
+
+                if (t == XML_END) {
+                        log_error("Premature end of XML data.");
+                        return -EBADMSG;
+                }
+
+                switch (state) {
+
+                case STATE_ANNOTATION:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_NAME;
+
+                                else if (streq_ptr(name, "value"))
+                                        state = STATE_VALUE;
+
+                                else {
+                                        log_error("Unexpected <annotation> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "annotation"))) {
+
+                                if (flags) {
+                                        if (streq_ptr(field, "org.freedesktop.DBus.Deprecated")) {
+
+                                                if (streq_ptr(value, "true"))
+                                                        *flags |= SD_BUS_VTABLE_DEPRECATED;
+
+                                        } else if (streq_ptr(field, "org.freedesktop.DBus.Method.NoReply")) {
+
+                                                if (streq_ptr(value, "true"))
+                                                        *flags |= SD_BUS_VTABLE_METHOD_NO_REPLY;
+
+                                        } else if (streq_ptr(field, "org.freedesktop.DBus.Property.EmitsChangedSignal")) {
+
+                                                if (streq_ptr(value, "const"))
+                                                        *flags |= SD_BUS_VTABLE_PROPERTY_CONST;
+                                                else if (streq_ptr(value, "invalidates"))
+                                                        *flags |= SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION;
+                                                else if (streq_ptr(value, "false"))
+                                                        *flags |= SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE;
+                                        }
+                                }
+
+                                return 0;
+
+                        } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <annotation>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE) {
+                                free(field);
+                                field = name;
+                                name = NULL;
+
+                                state = STATE_ANNOTATION;
+                        } else {
+                                log_error("Unexpected token in <annotation>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_VALUE:
+
+                        if (t == XML_ATTRIBUTE_VALUE) {
+                                free(value);
+                                value = name;
+                                name = NULL;
+
+                                state = STATE_ANNOTATION;
+                        } else {
+                                log_error("Unexpected token in <annotation>. (3)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                default:
+                        assert_not_reached("Bad state");
+                }
+        }
+}
+
+static int parse_xml_node(Context *context, const char *prefix, unsigned n_depth) {
+
+        enum {
+                STATE_NODE,
+                STATE_NODE_NAME,
+                STATE_INTERFACE,
+                STATE_INTERFACE_NAME,
+                STATE_METHOD,
+                STATE_METHOD_NAME,
+                STATE_METHOD_ARG,
+                STATE_METHOD_ARG_NAME,
+                STATE_METHOD_ARG_TYPE,
+                STATE_METHOD_ARG_DIRECTION,
+                STATE_SIGNAL,
+                STATE_SIGNAL_NAME,
+                STATE_SIGNAL_ARG,
+                STATE_SIGNAL_ARG_NAME,
+                STATE_SIGNAL_ARG_TYPE,
+                STATE_PROPERTY,
+                STATE_PROPERTY_NAME,
+                STATE_PROPERTY_TYPE,
+                STATE_PROPERTY_ACCESS,
+        } state = STATE_NODE;
+
+        _cleanup_free_ char *node_path = NULL;
+        const char *np = prefix;
+        int r;
+
+        assert(context);
+        assert(prefix);
+
+        if (n_depth > NODE_DEPTH_MAX) {
+                log_error("<node> depth too high.");
+                return -EINVAL;
+        }
+
+        for (;;) {
+                _cleanup_free_ char *name = NULL;
+                int t;
+
+                t = xml_tokenize(&context->current, &name, &context->xml_state, NULL);
+                if (t < 0) {
+                        log_error("XML parse error.");
+                        return t;
+                }
+
+                if (t == XML_END) {
+                        log_error("Premature end of XML data.");
+                        return -EBADMSG;
+                }
+
+                switch (state) {
+
+                case STATE_NODE:
+                        if (t == XML_ATTRIBUTE_NAME) {
+
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_NODE_NAME;
+                                else {
+                                        log_error("Unexpected <node> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+
+                        } else if (t == XML_TAG_OPEN) {
+
+                                if (streq_ptr(name, "interface"))
+                                        state = STATE_INTERFACE;
+
+                                else if (streq_ptr(name, "node")) {
+
+                                        r = parse_xml_node(context, np, n_depth+1);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected <node> tag %s.", name);
+                                        return -EBADMSG;
+                                }
+
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "node"))) {
+
+                                if (context->ops->on_path) {
+                                        r = context->ops->on_path(node_path ? node_path : np, context->userdata);
+                                        if (r < 0)
+                                                return r;
+                                }
+
+                                return 0;
+
+                        } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <node>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_NODE_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE) {
+
+                                free(node_path);
+
+                                if (name[0] == '/') {
+                                        node_path = name;
+                                        name = NULL;
+                                } else {
+
+                                        if (endswith(prefix, "/"))
+                                                node_path = strappend(prefix, name);
+                                        else
+                                                node_path = strjoin(prefix, "/", name, NULL);
+                                        if (!node_path)
+                                                return log_oom();
+                                }
+
+                                np = node_path;
+                                state = STATE_NODE;
+                        } else {
+                                log_error("Unexpected token in <node>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_INTERFACE:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_INTERFACE_NAME;
+                                else {
+                                        log_error("Unexpected <interface> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+
+                        } else if (t == XML_TAG_OPEN) {
+                                if (streq_ptr(name, "method"))
+                                        state = STATE_METHOD;
+                                else if (streq_ptr(name, "signal"))
+                                        state = STATE_SIGNAL;
+                                else if (streq_ptr(name, "property"))
+                                        state = STATE_PROPERTY;
+                                else if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, &context->interface_flags);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected <interface> tag %s.", name);
+                                        return -EINVAL;
+                                }
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "interface")))
+
+                                state = STATE_NODE;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <interface>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_INTERFACE_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_INTERFACE;
+                        else {
+                                log_error("Unexpected token in <interface>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_METHOD_NAME;
+                                else {
+                                        log_error("Unexpected <method> attribute %s", name);
+                                        return -EBADMSG;
+                                }
+                        } else if (t == XML_TAG_OPEN) {
+                                if (streq_ptr(name, "arg"))
+                                        state = STATE_METHOD_ARG;
+                                else if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, &context->member_flags);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected <method> tag %s.", name);
+                                        return -EINVAL;
+                                }
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "method")))
+
+                                state = STATE_INTERFACE;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <method> (1).");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_METHOD;
+                        else {
+                                log_error("Unexpected token in <method> (2).");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD_ARG:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_METHOD_ARG_NAME;
+                                else if (streq_ptr(name, "type"))
+                                        state = STATE_METHOD_ARG_TYPE;
+                                else if (streq_ptr(name, "direction"))
+                                         state = STATE_METHOD_ARG_DIRECTION;
+                                else {
+                                        log_error("Unexpected method <arg> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+                        } else if (t == XML_TAG_OPEN) {
+                                if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, NULL);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected method <arg> tag %s.", name);
+                                        return -EINVAL;
+                                }
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "arg")))
+
+                                state = STATE_METHOD;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in method <arg>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD_ARG_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_METHOD_ARG;
+                        else {
+                                log_error("Unexpected token in method <arg>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD_ARG_TYPE:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_METHOD_ARG;
+                        else {
+                                log_error("Unexpected token in method <arg>. (3)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_METHOD_ARG_DIRECTION:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_METHOD_ARG;
+                        else {
+                                log_error("Unexpected token in method <arg>. (4)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_SIGNAL:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_SIGNAL_NAME;
+                                else {
+                                        log_error("Unexpected <signal> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+                        } else if (t == XML_TAG_OPEN) {
+                                if (streq_ptr(name, "arg"))
+                                        state = STATE_SIGNAL_ARG;
+                                else if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, &context->member_flags);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected <signal> tag %s.", name);
+                                        return -EINVAL;
+                                }
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "signal")))
+
+                                state = STATE_INTERFACE;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <signal>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_SIGNAL_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_SIGNAL;
+                        else {
+                                log_error("Unexpected token in <signal>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+
+                case STATE_SIGNAL_ARG:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_SIGNAL_ARG_NAME;
+                                else if (streq_ptr(name, "type"))
+                                        state = STATE_SIGNAL_ARG_TYPE;
+                                else {
+                                        log_error("Unexpected signal <arg> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+                        } else if (t == XML_TAG_OPEN) {
+                                if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, NULL);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected signal <arg> tag %s.", name);
+                                        return -EINVAL;
+                                }
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "arg")))
+
+                                state = STATE_SIGNAL;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in signal <arg> (1).");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_SIGNAL_ARG_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_SIGNAL_ARG;
+                        else {
+                                log_error("Unexpected token in signal <arg> (2).");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_SIGNAL_ARG_TYPE:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_SIGNAL_ARG;
+                        else {
+                                log_error("Unexpected token in signal <arg> (3).");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_PROPERTY:
+
+                        if (t == XML_ATTRIBUTE_NAME) {
+                                if (streq_ptr(name, "name"))
+                                        state = STATE_PROPERTY_NAME;
+                                else if (streq_ptr(name, "type"))
+                                        state  = STATE_PROPERTY_TYPE;
+                                else if (streq_ptr(name, "access"))
+                                        state  = STATE_PROPERTY_ACCESS;
+                                else {
+                                        log_error("Unexpected <property> attribute %s.", name);
+                                        return -EBADMSG;
+                                }
+                        } else if (t == XML_TAG_OPEN) {
+
+                                if (streq_ptr(name, "annotation")) {
+                                        r = parse_xml_annotation(context, &context->member_flags);
+                                        if (r < 0)
+                                                return r;
+                                } else {
+                                        log_error("Unexpected <property> tag %s.", name);
+                                        return -EINVAL;
+                                }
+
+                        } else if (t == XML_TAG_CLOSE_EMPTY ||
+                                   (t == XML_TAG_CLOSE && streq_ptr(name, "property")))
+
+                                state = STATE_INTERFACE;
+
+                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                                log_error("Unexpected token in <property>. (1)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_PROPERTY_NAME:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_PROPERTY;
+                        else {
+                                log_error("Unexpected token in <property>. (2)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_PROPERTY_TYPE:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_PROPERTY;
+                        else {
+                                log_error("Unexpected token in <property>. (3)");
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case STATE_PROPERTY_ACCESS:
+
+                        if (t == XML_ATTRIBUTE_VALUE)
+                                state = STATE_PROPERTY;
+                        else {
+                                log_error("Unexpected token in <property>. (4)");
+                                return -EINVAL;
+                        }
+
+                        break;
+                }
+        }
+}
+
+int parse_xml_introspect(const char *prefix, const char *xml, const XMLIntrospectOps *ops, void *userdata) {
+        Context context = {
+                .ops = ops,
+                .userdata = userdata,
+                .current = xml,
+        };
+
+        int r;
+
+        assert(prefix);
+        assert(xml);
+        assert(ops);
+
+        for (;;) {
+                _cleanup_free_ char *name = NULL;
+
+                r = xml_tokenize(&context.current, &name, &context.xml_state, NULL);
+                if (r < 0) {
+                        log_error("XML parse error");
+                        return r;
+                }
+
+                if (r == XML_END)
+                        break;
+
+                if (r == XML_TAG_OPEN) {
+
+                        if (streq(name, "node")) {
+                                r = parse_xml_node(&context, prefix, 0);
+                                if (r < 0)
+                                        return r;
+                        } else {
+                                log_error("Unexpected tag '%s' in introspection data.", name);
+                                return -EBADMSG;
+                        }
+                } else if (r != XML_TEXT || !in_charset(name, WHITESPACE)) {
+                        log_error("Unexpected token.");
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/busctl-introspect.h b/src/libsystemd/sd-bus/busctl-introspect.h
new file mode 100644
index 0000000000..7c4cd6e5fd
--- /dev/null
+++ b/src/libsystemd/sd-bus/busctl-introspect.h
@@ -0,0 +1,35 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+
+typedef struct XMLIntrospectOps {
+        int (*on_path)(const char *path, void *userdata);
+        int (*on_interface)(const char *name, uint64_t flags);
+        int (*on_method)(const char *name, const char *signature, const char *result, uint64_t flags, void *userdata);
+        int (*on_signal)(const char *name, const char *signature, uint64_t flags, void *userdata);
+        int (*on_property)(const char *name, const char *signature, uint64_t flags);
+        int (*on_writable_property)(const char *name, const char *signature, uint64_t flags);
+} XMLIntrospectOps;
+
+int parse_xml_introspect(const char *prefix, const char *xml, const XMLIntrospectOps *ops, void *userdata);
diff --git a/src/libsystemd/sd-bus/busctl.c b/src/libsystemd/sd-bus/busctl.c
index 6d03692c7f..c58a97bc14 100644
--- a/src/libsystemd/sd-bus/busctl.c
+++ b/src/libsystemd/sd-bus/busctl.c
@@ -35,6 +35,7 @@
 #include "bus-util.h"
 #include "bus-dump.h"
 #include "bus-signature.h"
+#include "busctl-introspect.h"
 
 static bool arg_no_pager = false;
 static bool arg_legend = true;
@@ -304,550 +305,27 @@ static void print_tree(const char *prefix, char **l) {
         print_subtree(prefix, "/", l);
 }
 
-static int parse_xml_annotation(
-                const char **p,
-                void **xml_state) {
-
-
-        enum {
-                STATE_ANNOTATION,
-                STATE_NAME,
-                STATE_VALUE
-        } state = STATE_ANNOTATION;
-
-        for (;;) {
-                _cleanup_free_ char *name = NULL;
-
-                int t;
-
-                t = xml_tokenize(p, &name, xml_state, NULL);
-                if (t < 0) {
-                        log_error("XML parse error.");
-                        return t;
-                }
-
-                if (t == XML_END) {
-                        log_error("Premature end of XML data.");
-                        return -EBADMSG;
-                }
-
-                switch (state) {
-
-                case STATE_ANNOTATION:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_NAME;
-
-                                else if (streq_ptr(name, "value"))
-                                        state = STATE_VALUE;
-
-                                else {
-                                        log_error("Unexpected <annotation> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "annotation")))
-
-                                return 0;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <annotation>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_ANNOTATION;
-                        else {
-                                log_error("Unexpected token in <annotation>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_VALUE:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_ANNOTATION;
-                        else {
-                                log_error("Unexpected token in <annotation>. (3)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                default:
-                        assert_not_reached("Bad state");
-                }
-        }
-}
-
-static int parse_xml_node(
-                const char *prefix,
-                Set *paths,
-                const char **p,
-                void **xml_state) {
-
-        enum {
-                STATE_NODE,
-                STATE_NODE_NAME,
-                STATE_INTERFACE,
-                STATE_INTERFACE_NAME,
-                STATE_METHOD,
-                STATE_METHOD_NAME,
-                STATE_METHOD_ARG,
-                STATE_METHOD_ARG_NAME,
-                STATE_METHOD_ARG_TYPE,
-                STATE_METHOD_ARG_DIRECTION,
-                STATE_SIGNAL,
-                STATE_SIGNAL_NAME,
-                STATE_SIGNAL_ARG,
-                STATE_SIGNAL_ARG_NAME,
-                STATE_SIGNAL_ARG_TYPE,
-                STATE_PROPERTY,
-                STATE_PROPERTY_NAME,
-                STATE_PROPERTY_TYPE,
-                STATE_PROPERTY_ACCESS,
-        } state = STATE_NODE;
-
-        _cleanup_free_ char *node_path = NULL;
-        const char *np = prefix;
+static int on_path(const char *path, void *userdata) {
+        Set *paths = userdata;
         int r;
 
-        for (;;) {
-                _cleanup_free_ char *name = NULL;
-                int t;
-
-                t = xml_tokenize(p, &name, xml_state, NULL);
-                if (t < 0) {
-                        log_error("XML parse error.");
-                        return t;
-                }
-
-                if (t == XML_END) {
-                        log_error("Premature end of XML data.");
-                        return -EBADMSG;
-                }
-
-                switch (state) {
-
-                case STATE_NODE:
-                        if (t == XML_ATTRIBUTE_NAME) {
-
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_NODE_NAME;
-                                else {
-                                        log_error("Unexpected <node> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-
-                        } else if (t == XML_TAG_OPEN) {
-
-                                if (streq_ptr(name, "interface"))
-                                        state = STATE_INTERFACE;
-
-                                else if (streq_ptr(name, "node")) {
-
-                                        r = parse_xml_node(np, paths, p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected <node> tag %s.", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "node"))) {
-
-                                if (paths) {
-                                        if (!node_path) {
-                                                node_path = strdup(np);
-                                                if (!node_path)
-                                                        return log_oom();
-                                        }
-
-                                        r = set_put(paths, node_path);
-                                        if (r < 0)
-                                                return log_oom();
-                                        else if (r > 0)
-                                                node_path = NULL;
-                                }
-
-                                return 0;
-
-                        } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <node>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_NODE_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE) {
-
-                                free(node_path);
-
-                                if (name[0] == '/') {
-                                        node_path = name;
-                                        name = NULL;
-                                } else {
-
-                                        if (endswith(prefix, "/"))
-                                                node_path = strappend(prefix, name);
-                                        else
-                                                node_path = strjoin(prefix, "/", name, NULL);
-                                        if (!node_path)
-                                                return log_oom();
-                                }
-
-                                np = node_path;
-                                state = STATE_NODE;
-                        } else {
-                                log_error("Unexpected token in <node>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_INTERFACE:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_INTERFACE_NAME;
-                                else {
-                                        log_error("Unexpected <interface> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-
-                        } else if (t == XML_TAG_OPEN) {
-                                if (streq_ptr(name, "method"))
-                                        state = STATE_METHOD;
-                                else if (streq_ptr(name, "signal"))
-                                        state = STATE_SIGNAL;
-                                else if (streq_ptr(name, "property"))
-                                        state = STATE_PROPERTY;
-                                else if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected <interface> tag %s.", name);
-                                        return -EINVAL;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "interface")))
-
-                                state = STATE_NODE;
+        assert(paths);
 
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <interface>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_INTERFACE_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_INTERFACE;
-                        else {
-                                log_error("Unexpected token in <interface>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_METHOD_NAME;
-                                else {
-                                        log_error("Unexpected <method> attribute %s", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_OPEN) {
-                                if (streq_ptr(name, "arg"))
-                                        state = STATE_METHOD_ARG;
-                                else if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected <method> tag %s.", name);
-                                        return -EINVAL;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "method")))
-
-                                state = STATE_INTERFACE;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <method> (1).");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_METHOD;
-                        else {
-                                log_error("Unexpected token in <method> (2).");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD_ARG:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_METHOD_ARG_NAME;
-                                else if (streq_ptr(name, "type"))
-                                        state = STATE_METHOD_ARG_TYPE;
-                                else if (streq_ptr(name, "direction"))
-                                         state = STATE_METHOD_ARG_DIRECTION;
-                                else {
-                                        log_error("Unexpected method <arg> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_OPEN) {
-                                if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected method <arg> tag %s.", name);
-                                        return -EINVAL;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "arg")))
-
-                                state = STATE_METHOD;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in method <arg>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD_ARG_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_METHOD_ARG;
-                        else {
-                                log_error("Unexpected token in method <arg>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD_ARG_TYPE:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_METHOD_ARG;
-                        else {
-                                log_error("Unexpected token in method <arg>. (3)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_METHOD_ARG_DIRECTION:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_METHOD_ARG;
-                        else {
-                                log_error("Unexpected token in method <arg>. (4)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_SIGNAL:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_SIGNAL_NAME;
-                                else {
-                                        log_error("Unexpected <signal> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_OPEN) {
-                                if (streq_ptr(name, "arg"))
-                                        state = STATE_SIGNAL_ARG;
-                                else if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected <signal> tag %s.", name);
-                                        return -EINVAL;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "signal")))
-
-                                state = STATE_INTERFACE;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <signal>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_SIGNAL_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_SIGNAL;
-                        else {
-                                log_error("Unexpected token in <signal>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-
-                case STATE_SIGNAL_ARG:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_SIGNAL_ARG_NAME;
-                                else if (streq_ptr(name, "type"))
-                                        state = STATE_SIGNAL_ARG_TYPE;
-                                else {
-                                        log_error("Unexpected signal <arg> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_OPEN) {
-                                if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected signal <arg> tag %s.", name);
-                                        return -EINVAL;
-                                }
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "arg")))
-
-                                state = STATE_SIGNAL;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in signal <arg> (1).");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_SIGNAL_ARG_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_SIGNAL_ARG;
-                        else {
-                                log_error("Unexpected token in signal <arg> (2).");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_SIGNAL_ARG_TYPE:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_SIGNAL_ARG;
-                        else {
-                                log_error("Unexpected token in signal <arg> (3).");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_PROPERTY:
-
-                        if (t == XML_ATTRIBUTE_NAME) {
-                                if (streq_ptr(name, "name"))
-                                        state = STATE_PROPERTY_NAME;
-                                else if (streq_ptr(name, "type"))
-                                        state  = STATE_PROPERTY_TYPE;
-                                else if (streq_ptr(name, "access"))
-                                        state  = STATE_PROPERTY_ACCESS;
-                                else {
-                                        log_error("Unexpected <property> attribute %s.", name);
-                                        return -EBADMSG;
-                                }
-                        } else if (t == XML_TAG_OPEN) {
-
-                                if (streq_ptr(name, "annotation")) {
-                                        r = parse_xml_annotation(p, xml_state);
-                                        if (r < 0)
-                                                return r;
-                                } else {
-                                        log_error("Unexpected <property> tag %s.", name);
-                                        return -EINVAL;
-                                }
-
-                        } else if (t == XML_TAG_CLOSE_EMPTY ||
-                                   (t == XML_TAG_CLOSE && streq_ptr(name, "property")))
-
-                                state = STATE_INTERFACE;
-
-                        else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                                log_error("Unexpected token in <property>. (1)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_PROPERTY_NAME:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_PROPERTY;
-                        else {
-                                log_error("Unexpected token in <property>. (2)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_PROPERTY_TYPE:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_PROPERTY;
-                        else {
-                                log_error("Unexpected token in <property>. (3)");
-                                return -EINVAL;
-                        }
-
-                        break;
-
-                case STATE_PROPERTY_ACCESS:
-
-                        if (t == XML_ATTRIBUTE_VALUE)
-                                state = STATE_PROPERTY;
-                        else {
-                                log_error("Unexpected token in <property>. (4)");
-                                return -EINVAL;
-                        }
+        r = set_put_strdup(paths, path);
+        if (r < 0)
+                return log_oom();
 
-                        break;
-                }
-        }
+        return 0;
 }
 
 static int find_nodes(sd_bus *bus, const char *service, const char *path, Set *paths) {
+        const XMLIntrospectOps ops = {
+                .on_path = on_path,
+        };
+
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-        _cleanup_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-        const char *xml, *p;
-        void *xml_state = NULL;
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *xml;
         int r;
 
         r = sd_bus_call_method(bus, service, path, "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
@@ -861,37 +339,7 @@ static int find_nodes(sd_bus *bus, const char *service, const char *path, Set *p
                 return bus_log_parse_error(r);
 
         /* fputs(xml, stdout); */
-
-        p = xml;
-        for (;;) {
-                _cleanup_free_ char *name = NULL;
-
-                r = xml_tokenize(&p, &name, &xml_state, NULL);
-                if (r < 0) {
-                        log_error("XML parse error");
-                        return r;
-                }
-
-                if (r == XML_END)
-                        break;
-
-                if (r == XML_TAG_OPEN) {
-
-                        if (streq(name, "node")) {
-                                r = parse_xml_node(path, paths, &p, &xml_state);
-                                if (r < 0)
-                                        return r;
-                        } else {
-                                log_error("Unexpected tag '%s' in introspection data.", name);
-                                return -EBADMSG;
-                        }
-                } else if (r != XML_TEXT || !in_charset(name, WHITESPACE)) {
-                        log_error("Unexpected token.");
-                        return -EINVAL;
-                }
-        }
-
-        return 0;
+        return parse_xml_introspect(path, xml, &ops, paths);
 }
 
 static int tree_one(sd_bus *bus, const char *service, const char *prefix) {