| 1 | /* |
| 2 | * Copyright © 2006-2007 Daniel Stone |
| 3 | * |
| 4 | * Permission is hereby granted, free of charge, to any person obtaining a |
| 5 | * copy of this software and associated documentation files (the "Software"), |
| 6 | * to deal in the Software without restriction, including without limitation |
| 7 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| 8 | * and/or sell copies of the Software, and to permit persons to whom the |
| 9 | * Software is furnished to do so, subject to the following conditions: |
| 10 | * |
| 11 | * The above copyright notice and this permission notice (including the next |
| 12 | * paragraph) shall be included in all copies or substantial portions of the |
| 13 | * Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| 18 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 19 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 20 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| 21 | * DEALINGS IN THE SOFTWARE. |
| 22 | * |
| 23 | * Author: Daniel Stone <daniel@fooishbar.org> |
| 24 | */ |
| 25 | |
| 26 | #ifdef HAVE_DIX_CONFIG_H |
| 27 | #include <dix-config.h> |
| 28 | #endif |
| 29 | |
| 30 | #include <dbus/dbus.h> |
| 31 | #include <sys/select.h> |
| 32 | |
| 33 | #include "config-backends.h" |
| 34 | #include "dix.h" |
| 35 | #include "os.h" |
| 36 | |
| 37 | /* How often to attempt reconnecting when we get booted off the bus. */ |
| 38 | #define RECONNECT_DELAY (10 * 1000) /* in ms */ |
| 39 | |
| 40 | struct dbus_core_info { |
| 41 | int fd; |
| 42 | DBusConnection *connection; |
| 43 | OsTimerPtr timer; |
| 44 | struct config_dbus_core_hook *hooks; |
| 45 | }; |
| 46 | static struct dbus_core_info bus_info; |
| 47 | |
| 48 | static CARD32 reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg); |
| 49 | |
| 50 | static void |
| 51 | wakeup_handler(pointer data, int err, pointer read_mask) |
| 52 | { |
| 53 | struct dbus_core_info *info = data; |
| 54 | |
| 55 | if (info->connection && FD_ISSET(info->fd, (fd_set *) read_mask)) { |
| 56 | do { |
| 57 | dbus_connection_read_write_dispatch(info->connection, 0); |
| 58 | } while (info->connection && |
| 59 | dbus_connection_get_is_connected(info->connection) && |
| 60 | dbus_connection_get_dispatch_status(info->connection) == |
| 61 | DBUS_DISPATCH_DATA_REMAINS); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | static void |
| 66 | block_handler(pointer data, struct timeval **tv, pointer read_mask) |
| 67 | { |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Disconnect (if we haven't already been forcefully disconnected), clean up |
| 72 | * after ourselves, and call all registered disconnect hooks. |
| 73 | */ |
| 74 | static void |
| 75 | teardown(void) |
| 76 | { |
| 77 | struct config_dbus_core_hook *hook; |
| 78 | |
| 79 | if (bus_info.timer) { |
| 80 | TimerFree(bus_info.timer); |
| 81 | bus_info.timer = NULL; |
| 82 | } |
| 83 | |
| 84 | /* We should really have pre-disconnect hooks and run them here, for |
| 85 | * completeness. But then it gets awkward, given that you can't |
| 86 | * guarantee that they'll be called ... */ |
| 87 | if (bus_info.connection) |
| 88 | dbus_connection_unref(bus_info.connection); |
| 89 | |
| 90 | RemoveBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info); |
| 91 | if (bus_info.fd != -1) |
| 92 | RemoveGeneralSocket(bus_info.fd); |
| 93 | bus_info.fd = -1; |
| 94 | bus_info.connection = NULL; |
| 95 | |
| 96 | for (hook = bus_info.hooks; hook; hook = hook->next) { |
| 97 | if (hook->disconnect) |
| 98 | hook->disconnect(hook->data); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * This is a filter, which only handles the disconnected signal, which |
| 104 | * doesn't go to the normal message handling function. This takes |
| 105 | * precedence over the message handling function, so have have to be |
| 106 | * careful to ignore anything we don't want to deal with here. |
| 107 | */ |
| 108 | static DBusHandlerResult |
| 109 | message_filter(DBusConnection * connection, DBusMessage * message, void *data) |
| 110 | { |
| 111 | /* If we get disconnected, then take everything down, and attempt to |
| 112 | * reconnect immediately (assuming it's just a restart). The |
| 113 | * connection isn't valid at this point, so throw it out immediately. */ |
| 114 | if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) { |
| 115 | DebugF("[config/dbus-core] disconnected from bus\n"); |
| 116 | bus_info.connection = NULL; |
| 117 | teardown(); |
| 118 | |
| 119 | if (bus_info.timer) |
| 120 | TimerFree(bus_info.timer); |
| 121 | bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL); |
| 122 | |
| 123 | return DBUS_HANDLER_RESULT_HANDLED; |
| 124 | } |
| 125 | |
| 126 | return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Attempt to connect to the system bus, and set a filter to deal with |
| 131 | * disconnection (see message_filter above). |
| 132 | * |
| 133 | * @return 1 on success, 0 on failure. |
| 134 | */ |
| 135 | static int |
| 136 | connect_to_bus(void) |
| 137 | { |
| 138 | DBusError error; |
| 139 | struct config_dbus_core_hook *hook; |
| 140 | |
| 141 | dbus_error_init(&error); |
| 142 | bus_info.connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error); |
| 143 | if (!bus_info.connection || dbus_error_is_set(&error)) { |
| 144 | DebugF("[config/dbus-core] error connecting to system bus: %s (%s)\n", |
| 145 | error.name, error.message); |
| 146 | goto err_begin; |
| 147 | } |
| 148 | |
| 149 | /* Thankyou. Really, thankyou. */ |
| 150 | dbus_connection_set_exit_on_disconnect(bus_info.connection, FALSE); |
| 151 | |
| 152 | if (!dbus_connection_get_unix_fd(bus_info.connection, &bus_info.fd)) { |
| 153 | ErrorF("[config/dbus-core] couldn't get fd for system bus\n"); |
| 154 | goto err_unref; |
| 155 | } |
| 156 | |
| 157 | if (!dbus_connection_add_filter(bus_info.connection, message_filter, |
| 158 | &bus_info, NULL)) { |
| 159 | ErrorF("[config/dbus-core] couldn't add filter: %s (%s)\n", error.name, |
| 160 | error.message); |
| 161 | goto err_fd; |
| 162 | } |
| 163 | |
| 164 | dbus_error_free(&error); |
| 165 | AddGeneralSocket(bus_info.fd); |
| 166 | |
| 167 | RegisterBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info); |
| 168 | |
| 169 | for (hook = bus_info.hooks; hook; hook = hook->next) { |
| 170 | if (hook->connect) |
| 171 | hook->connect(bus_info.connection, hook->data); |
| 172 | } |
| 173 | |
| 174 | return 1; |
| 175 | |
| 176 | err_fd: |
| 177 | bus_info.fd = -1; |
| 178 | err_unref: |
| 179 | dbus_connection_unref(bus_info.connection); |
| 180 | bus_info.connection = NULL; |
| 181 | err_begin: |
| 182 | dbus_error_free(&error); |
| 183 | |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | static CARD32 |
| 188 | reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg) |
| 189 | { |
| 190 | if (connect_to_bus()) { |
| 191 | TimerFree(bus_info.timer); |
| 192 | bus_info.timer = NULL; |
| 193 | return 0; |
| 194 | } |
| 195 | else { |
| 196 | return RECONNECT_DELAY; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | int |
| 201 | config_dbus_core_add_hook(struct config_dbus_core_hook *hook) |
| 202 | { |
| 203 | struct config_dbus_core_hook **prev; |
| 204 | |
| 205 | for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next); |
| 206 | |
| 207 | hook->next = NULL; |
| 208 | *prev = hook; |
| 209 | |
| 210 | /* If we're already connected, call the connect hook. */ |
| 211 | if (bus_info.connection) |
| 212 | hook->connect(bus_info.connection, hook->data); |
| 213 | |
| 214 | return 1; |
| 215 | } |
| 216 | |
| 217 | void |
| 218 | config_dbus_core_remove_hook(struct config_dbus_core_hook *hook) |
| 219 | { |
| 220 | struct config_dbus_core_hook **prev; |
| 221 | |
| 222 | for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next) { |
| 223 | if (*prev == hook) { |
| 224 | *prev = hook->next; |
| 225 | break; |
| 226 | } |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | int |
| 231 | config_dbus_core_init(void) |
| 232 | { |
| 233 | memset(&bus_info, 0, sizeof(bus_info)); |
| 234 | bus_info.fd = -1; |
| 235 | bus_info.hooks = NULL; |
| 236 | bus_info.connection = NULL; |
| 237 | bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL); |
| 238 | |
| 239 | return 1; |
| 240 | } |
| 241 | |
| 242 | void |
| 243 | config_dbus_core_fini(void) |
| 244 | { |
| 245 | teardown(); |
| 246 | } |