dbus/introspection.c

   1 /* -*- Mode: C ; c-basic-offset: 2 -*- */
   2 /*
   3  * LADI Session Handler (ladish)
   4  *
   5  * Copyright (C) 2008, 2009 Nedko Arnaudov <nedko@arnaudov.name>
   6  * Copyright (C) 2008 Juuso Alasuutari <juuso.alasuutari@gmail.com>
   7  *
   8  **************************************************************************
   9  * This file contains the D-Bus introspection interface handler
  10  **************************************************************************
  11  *
  12  * LADI Session Handler is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * LADI Session Handler is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with LADI Session Handler. If not, see <http://www.gnu.org/licenses/>
  24  * or write to the Free Software Foundation, Inc.,
  25  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <dbus/dbus.h>
  32
  33 #include "../common/safety.h"
  34 #include "../common/debug.h"
  35 #include "introspection.h"
  36 #include "signal.h"
  37 #include "method.h"
  38
  39 #define write_buf(args...) buf_ptr += sprintf(buf_ptr, ## args)
  40
  41 DBusMessage *
  42 introspection_new(object_path_t *path)
  43 {
  44   if (!path) {
  45     lash_debug("Invalid arguments");
  46     return NULL;
  47   }
  48
  49   lash_debug("Creating introspection message");
  50
  51   char *xml_data, *buf_ptr;
  52   const interface_t **iface_pptr;
  53   const method_t *method_ptr;
  54   const method_arg_t *method_arg_ptr;
  55   const signal_t *signal_ptr;
  56   const signal_arg_t *signal_arg_ptr;
  57   DBusMessage *msg;
  58   DBusMessageIter iter;
  59
  60   /*
  61    * Create introspection XML data.
  62    */
  63
  64   xml_data = lash_malloc(1, 16384);
  65   buf_ptr = xml_data;
  66
  67   write_buf("<!DOCTYPE node PUBLIC \"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN\"\n"
  68             " \"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd\">\n"
  69             "<node name=\"%s\">\n", path->name);
  70
  71   /* Add the object path's interfaces. */
  72   for (iface_pptr = (const interface_t **) path->interfaces;
  73        iface_pptr && *iface_pptr;
  74        ++iface_pptr) {
  75     write_buf("  <interface name=\"%s\">\n",
  76               (*iface_pptr)->name);
  77
  78     /* Add the interface's methods. */
  79     for (method_ptr = (const method_t *) (*iface_pptr)->methods;
  80          method_ptr && method_ptr->name;
  81          ++method_ptr) {
  82       write_buf("    <method name=\"%s\">\n",
  83                 method_ptr->name);
  84
  85       /* Add the method's arguments. */
  86       for (method_arg_ptr = (const method_arg_t *) method_ptr->args;
  87       method_arg_ptr && method_arg_ptr->name;
  88       ++method_arg_ptr) {
  89         write_buf("      <arg name=\"%s\" type=\"%s\" direction=\"%s\" />\n",
  90                   method_arg_ptr->name,
  91                   method_arg_ptr->type,
  92                   method_arg_ptr->direction_in ? "in" : "out");
  93       }
  94       write_buf("    </method>\n");
  95     }
  96
  97     /* Add the interface's signals. */
  98     for (signal_ptr = (const signal_t *) (*iface_pptr)->signals;
  99          signal_ptr && signal_ptr->name;
 100          ++signal_ptr) {
 101       write_buf("    <signal name=\"%s\">\n",
 102                 signal_ptr->name);
 103
 104       /* Add the signal's arguments. */
 105       for (signal_arg_ptr = (const signal_arg_t *) signal_ptr->args;
 106       signal_arg_ptr && signal_arg_ptr->name;
 107       ++signal_arg_ptr) {
 108         write_buf("      <arg name=\"%s\" type=\"%s\" />\n",
 109                   signal_arg_ptr->name,
 110                   signal_arg_ptr->type);
 111       }
 112       write_buf("    </signal>\n");
 113     }
 114     write_buf("  </interface>\n");
 115   }
 116   write_buf("</node>");
 117
 118   /*
 119    * Create a D-Bus message from the XML data.
 120    */
 121
 122   if ((msg = dbus_message_new(DBUS_MESSAGE_TYPE_METHOD_RETURN))) {
 123     dbus_message_iter_init_append(msg, &iter);
 124     if (dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING,
 125                                         (const void *) &xml_data)) {
 126       dbus_message_set_no_reply(msg, TRUE);
 127     } else {
 128       dbus_message_unref(msg);
 129       msg = NULL;
 130       lash_error("Failed to append data to introspection message");
 131     }
 132   } else {
 133     lash_error("Failed to create introspection message");
 134   }
 135
 136   free(xml_data);
 137   xml_data = buf_ptr = NULL;
 138
 139   return msg;
 140 }
 141
 142 #undef write_buf
 143
 144 void
 145 introspection_destroy(object_path_t *path)
 146 {
 147   lash_debug("Destroying introspection message");
 148
 149   if (path && path->introspection) {
 150     dbus_message_unref(path->introspection);
 151     path->introspection = NULL;
 152   }
 153 #ifdef LASH_DEBUG
 154   else
 155     lash_debug("Nothing to destroy");
 156 #endif
 157 }
 158
 159 static bool
 160 introspection_handler(const interface_t *interface,
 161                       method_call_t     *call)
 162 {
 163   if (strcmp(call->method_name, "Introspect") == 0) {
 164     /* Try to construct the instrospection message */
 165     if ((call->reply = dbus_message_copy(((object_path_t *) call->context)->introspection))
 166         && dbus_message_set_destination(call->reply, dbus_message_get_sender(call->message))
 167         && dbus_message_set_reply_serial(call->reply, dbus_message_get_serial(call->message))) {
 168       return true;
 169     }
 170
 171     /* Failed; clear the message data if it exists. */
 172     if (call->reply) {
 173       dbus_message_unref(call->reply);
 174       call->reply = NULL;
 175     }
 176
 177     lash_error("Ran out of memory trying to copy introspection message");
 178
 179     /* Even after an error we need to return true, because the
 180        handler is only supposed to return false if a nonexistent
 181        method is requested. */
 182     return true;
 183   }
 184
 185   /* The requested method wasn't "Introspect". */
 186   return false;
 187 }
 188
 189
 190 /*
 191  * Interface description.
 192  */
 193
 194 METHOD_ARGS_BEGIN(Introspect, "Get introspection XML")
 195   METHOD_ARG_DESCRIBE_OUT("xml_data", "s", "XML description of the object")
 196 METHOD_ARGS_END
 197
 198 METHODS_BEGIN
 199   METHOD_DESCRIBE(Introspect, NULL)
 200 METHODS_END
 201
 202 INTERFACE_BEGIN(g_dbus_interface_dtor_introspectable, "org.freedesktop.DBus.Introspectable")
 203   INTERFACE_HANDLER(introspection_handler)
 204   INTERFACE_EXPOSE_METHODS
 205 INTERFACE_END
 206
 207 /* EOF */