1 /* 2 * Server binding/registration. 3 * 4 * Copyright (C) 2018, 2019, 2020, 2021, 2022 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include <l4/re/env.h> 23 #include <l4/sys/factory.h> 24 #include <l4/sys/kernel_object.h> 25 #include <l4/sys/rcv_endpoint.h> 26 #include <l4/sys/thread.h> 27 #include <l4/util/util.h> 28 29 #include <stdlib.h> 30 31 #include "cap_alloc.h" 32 #include "irq.h" 33 #include "server.h" 34 35 36 37 /* Associate an IRQ with the IPC gate in the main thread to handle gate deletion 38 notifications. */ 39 40 long ipc_server_apply_irq(l4_cap_idx_t cap, l4_cap_idx_t *irq) 41 { 42 return ipc_server_apply_irq_for_thread(cap, irq, l4re_env()->main_thread); 43 } 44 45 /* Associate an IRQ with the IPC gate in the given thread to handle gate deletion 46 notifications. */ 47 48 long ipc_server_apply_irq_for_thread(l4_cap_idx_t cap, l4_cap_idx_t *irq, l4_cap_idx_t thread) 49 { 50 /* Create an IRQ for the gate. */ 51 52 long err = ipc_create_irq(irq); 53 54 if (err) 55 return err; 56 57 /* Bind the IRQ to the thread, presenting the label if it provides the 58 incoming message. */ 59 60 err = l4_error(l4_rcv_ep_bind_thread(*irq, thread, (l4_umword_t) *irq)); 61 62 if (err) 63 { 64 ipc_cap_free_um(*irq); 65 return err; 66 } 67 68 /* Register for notifications. The thread associated with the gate seems to be 69 needed. */ 70 71 err = l4_error(l4_thread_register_del_irq(thread, *irq)); 72 73 if (err) 74 { 75 ipc_cap_free_um(*irq); 76 return err; 77 } 78 79 /* Decrease the reference count on the server capability (IPC gate). */ 80 81 return l4_error(l4_kobject_dec_refcnt(cap, 1)); 82 } 83 84 85 86 /* Bind the main thread to the named capability, employing an identifier for 87 the IPC gate and returning the capability index. */ 88 89 long ipc_server_bind(const char *name, l4_umword_t id, l4_cap_idx_t *server) 90 { 91 /* Obtain a reference to the device. */ 92 93 *server = l4re_env_get_cap(name); 94 95 if (l4_is_invalid_cap(*server)) 96 return -L4_ENOENT; 97 98 /* Bind to an IPC gate with the label identifying the server as message 99 destination. */ 100 101 return l4_error(l4_rcv_ep_bind_thread(*server, l4re_env()->main_thread, id)); 102 } 103 104 /* Initialise a new server capability, binding it to the main thread. */ 105 106 long ipc_server_new(l4_cap_idx_t *cap, void *obj) 107 { 108 return ipc_server_new_for_thread(cap, obj, l4re_env()->main_thread); 109 } 110 111 /* Initialise a new server capability, binding it to the given thread. */ 112 113 long ipc_server_new_for_thread(l4_cap_idx_t *cap, void *obj, l4_cap_idx_t thread) 114 { 115 l4_umword_t label = (l4_umword_t) obj; 116 117 /* Create an IPC gate, presenting the resource's label if this gate provides 118 the message. */ 119 120 return ipc_server_new_gate_for_thread(cap, thread, label); 121 } 122 123 /* Create an IPC gate, exporting via a new capability an object with the given 124 identifier. */ 125 126 long ipc_server_new_gate(l4_cap_idx_t *ref, l4_umword_t id) 127 { 128 return ipc_server_new_gate_for_thread(ref, l4re_env()->main_thread, id); 129 } 130 131 /* Create an IPC gate associated with a specific thread. */ 132 133 long ipc_server_new_gate_for_thread(l4_cap_idx_t *ref, l4_cap_idx_t thread, l4_umword_t id) 134 { 135 long err; 136 137 *ref = ipc_cap_alloc(); 138 139 if (l4_is_invalid_cap(*ref)) 140 return -L4_ENOENT; 141 142 /* Associate the object with an IPC gate. */ 143 144 err = l4_error(l4_factory_create_gate(l4re_env()->factory, *ref, thread, id)); 145 146 if (err) 147 ipc_cap_free_um(*ref); 148 149 return err; 150 } 151 152 153 154 /* Support for the convenience macro starting a server for a given object. */ 155 156 long _ipc_server_loop_for(int expected_items, void *handler_obj, 157 ipc_server_handler_type handler, const char *name) 158 { 159 ipc_server_config_type config; 160 long err; 161 162 if (name != NULL) 163 { 164 err = ipc_server_bind(name, (l4_umword_t) &config, &config.server); 165 if (err) 166 return err; 167 } 168 169 _ipc_server_init_for(&config, expected_items, handler_obj, handler); 170 171 return ipc_server_start_config(&config); 172 } 173 174 /* Initialise a server for a given object. */ 175 176 long _ipc_server_init_for(ipc_server_config_type *config, int expected_items, 177 void *handler_obj, ipc_server_handler_type handler) 178 { 179 ipc_server_init_config(config); 180 181 config->expected_items = expected_items; 182 config->handler = handler; 183 config->handler_obj = handler_obj; 184 185 return L4_EOK; 186 } 187 188 /* Associate a new configuration with an existing server endpoint. */ 189 190 long _ipc_server_add_config(ipc_server_config_type *config, int expected_items, 191 void *handler_obj, ipc_server_handler_type handler, 192 l4_cap_idx_t thread) 193 { 194 _ipc_server_init_for(config, expected_items, handler_obj, handler); 195 return ipc_server_start_config_thread(config, thread); 196 } 197 198 /* Complete initialisation of a server in the given thread. */ 199 200 long ipc_server_start_config_thread(ipc_server_config_type *config, 201 l4_cap_idx_t thread) 202 { 203 config->thread = thread; 204 config->config_thread = 1; 205 206 return ipc_server_start_config(config); 207 } 208 209 210 211 /* A server main loop handling endpoint deletion for an IPC gate dedicated to 212 a particular object within its own thread. */ 213 214 long ipc_server_managed_loop(int expected_items, ipc_server_config_type *config) 215 { 216 ipc_message_t msg; 217 l4_umword_t label, irq_label; 218 219 /* Permit other endpoints by dynamically interpreting the label. */ 220 221 ipc_server_config_type *config_from_label; 222 223 /* Declare the extent to which capabilities are expected in messages. */ 224 225 long err = ipc_message_expect(&msg, expected_items); 226 227 if (err) 228 return err; 229 230 /* Wait for an incoming message. */ 231 232 while (1) 233 { 234 ipc_message_wait(&msg, &label); 235 236 /* Clear lower label bits. */ 237 238 label = label & ~3UL; 239 240 /* Ignore erroneous messages. */ 241 242 if (l4_ipc_error(msg.tag, l4_utcb())) 243 continue; 244 245 /* Message involves the IPC gate itself. */ 246 247 irq_label = (l4_umword_t) config->irq; 248 249 if (!config->notifications || (config->notifications && (label != irq_label))) 250 { 251 config_from_label = (ipc_server_config_type *) label; 252 config_from_label->handler(&msg, config_from_label->handler_obj); 253 } 254 255 /* Message involves the IRQ or a termination condition occurred. */ 256 257 else if ((config->notifications && (label == irq_label)) || msg.terminating) 258 break; 259 } 260 261 /* Free expected capabilities. */ 262 263 ipc_message_free(&msg); 264 265 return L4_EOK; 266 } 267 268 /* A pthread-compatible mainloop initiation function. */ 269 270 void *ipc_server_start_mainloop(void *data) 271 { 272 ipc_server_config_type *config = (ipc_server_config_type *) data; 273 274 long err = ipc_server_managed_loop(config->expected_items, config); 275 276 if (config->finaliser != NULL) 277 config->finaliser(config); 278 279 return (void *) err; 280 } 281 282 /* Wait for an incoming message via an IPC gate dedicated to a particular 283 object within its own thread. */ 284 285 l4_msgtag_t ipc_server_wait(l4_umword_t id) 286 { 287 l4_umword_t label; 288 l4_msgtag_t tag; 289 290 /* Ignore errors and messages not intended for the identified gate. */ 291 292 do tag = l4_ipc_wait(l4_utcb(), &label, L4_IPC_NEVER); 293 while (l4_ipc_error(tag, l4_utcb()) || (label & ~3UL) != id); 294 295 return tag; 296 } 297 298 299 300 /* Finalise a server configuration. */ 301 302 void ipc_server_finalise_config(ipc_server_config_type *config) 303 { 304 if (l4_is_valid_cap(config->server)) 305 { 306 ipc_cap_free_um(config->server); 307 config->server = L4_INVALID_CAP; 308 } 309 310 if (l4_is_valid_cap(config->irq)) 311 { 312 ipc_cap_free_um(config->irq); 313 config->irq = L4_INVALID_CAP; 314 } 315 } 316 317 /* Discard any uninitiated thread. */ 318 319 void ipc_server_discard_thread(ipc_server_config_type *config) 320 { 321 if (config->config_thread && l4_is_valid_cap(config->thread)) 322 { 323 ipc_cap_free_um(config->thread); 324 config->thread = L4_INVALID_CAP; 325 } 326 } 327 328 /* Initialise a server configuration. */ 329 330 void ipc_server_init_config(ipc_server_config_type *config) 331 { 332 /* No object references defined. */ 333 334 config->handler_obj = NULL; 335 config->finaliser_obj = NULL; 336 337 /* Expect no capability items by default. */ 338 339 config->expected_items = 0; 340 341 /* No handler or finaliser defined. */ 342 343 config->handler = NULL; 344 config->finaliser = NULL; 345 346 /* No separate thread for the main loop. */ 347 348 config->config_thread = 0; 349 350 /* Main thread by default with IPC gate to be allocated. */ 351 352 config->thread = l4re_env()->main_thread; 353 config->server = L4_INVALID_CAP; 354 355 /* No notifications and with IRQ to be potentially allocated. */ 356 357 config->notifications = 0; 358 config->irq = L4_INVALID_CAP; 359 } 360 361 /* Initialise and start a server using the given configuration. */ 362 363 long ipc_server_start_config(ipc_server_config_type *config) 364 { 365 long err; 366 367 /* Allocate a new IPC gate if one is not already defined. */ 368 369 if (l4_is_invalid_cap(config->server)) 370 { 371 err = ipc_server_new_for_thread(&config->server, config, config->thread); 372 373 if (err) 374 return err; 375 } 376 377 /* Allocate an IRQ for notifications if requested. */ 378 379 if (config->notifications) 380 { 381 err = ipc_server_apply_irq_for_thread(config->server, &config->irq, config->thread); 382 383 if (err) 384 return err; 385 386 /* Unmask the interrupt. */ 387 388 ipc_init_irq(config->irq); 389 } 390 391 /* With a separate thread, return the last status value. Otherwise, invoke the 392 main loop. */ 393 394 if (config->config_thread) 395 return L4_EOK; 396 else 397 return (long) ipc_server_start_mainloop(config); 398 } 399 400 /* vim: tabstop=2 expandtab shiftwidth=2 401 */