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 } 185 186 /* Associate a new configuration with an existing server endpoint. */ 187 188 long _ipc_server_add_config(ipc_server_config_type *config, int expected_items, 189 void *handler_obj, ipc_server_handler_type handler, 190 l4_cap_idx_t thread) 191 { 192 _ipc_server_init_for(config, expected_items, handler_obj, handler); 193 return ipc_server_start_config_thread(config, thread); 194 } 195 196 /* Complete initialisation of a server in the given thread. */ 197 198 long ipc_server_start_config_thread(ipc_server_config_type *config, 199 l4_cap_idx_t thread) 200 { 201 config->thread = thread; 202 config->config_thread = 1; 203 204 return ipc_server_start_config(config); 205 } 206 207 208 209 /* A server main loop handling endpoint deletion for an IPC gate dedicated to 210 a particular object within its own thread. */ 211 212 long ipc_server_managed_loop(int expected_items, ipc_server_config_type *config) 213 { 214 ipc_message_t msg; 215 l4_umword_t label, irq_label = (l4_umword_t) config->irq; 216 217 /* Permit other endpoints by dynamically interpreting the label. */ 218 219 ipc_server_config_type *config_from_label; 220 221 /* Declare the extent to which capabilities are expected in messages. */ 222 223 long err = ipc_message_expect(&msg, expected_items); 224 225 if (err) 226 return err; 227 228 /* Unmask the interrupt. */ 229 230 if (l4_is_valid_cap(config->irq)) 231 ipc_init_irq(config->irq); 232 233 /* Wait for an incoming message. */ 234 235 while (1) 236 { 237 ipc_message_wait(&msg, &label); 238 239 /* Clear lower label bits. */ 240 241 label = label & ~3UL; 242 243 /* Ignore erroneous messages. */ 244 245 if (l4_ipc_error(msg.tag, l4_utcb())) 246 continue; 247 248 /* Message involves the IPC gate itself. */ 249 250 if (label != irq_label) 251 { 252 config_from_label = (ipc_server_config_type *) label; 253 config_from_label->handler(&msg, config_from_label->handler_obj); 254 } 255 256 /* Message involves the IRQ or a termination condition occurred. */ 257 258 if ((label == irq_label) || msg.terminating) 259 break; 260 } 261 262 /* Free expected capabilities. */ 263 264 ipc_message_free(&msg); 265 266 return L4_EOK; 267 } 268 269 /* A pthread-compatible mainloop initiation function. */ 270 271 void *ipc_server_start_mainloop(void *data) 272 { 273 ipc_server_config_type *config = (ipc_server_config_type *) data; 274 275 long err = ipc_server_managed_loop(config->expected_items, config); 276 277 if (config->finaliser != NULL) 278 config->finaliser(config); 279 280 return (void *) err; 281 } 282 283 /* Wait for an incoming message via an IPC gate dedicated to a particular 284 object within its own thread. */ 285 286 l4_msgtag_t ipc_server_wait(l4_umword_t id) 287 { 288 l4_umword_t label; 289 l4_msgtag_t tag; 290 291 /* Ignore errors and messages not intended for the identified gate. */ 292 293 do tag = l4_ipc_wait(l4_utcb(), &label, L4_IPC_NEVER); 294 while (l4_ipc_error(tag, l4_utcb()) || (label & ~3UL) != id); 295 296 return tag; 297 } 298 299 300 301 /* Finalise a server configuration. */ 302 303 void ipc_server_finalise_config(ipc_server_config_type *config) 304 { 305 if (l4_is_valid_cap(config->server)) 306 { 307 ipc_cap_free_um(config->server); 308 config->server = L4_INVALID_CAP; 309 } 310 311 if (l4_is_valid_cap(config->irq)) 312 { 313 ipc_cap_free_um(config->irq); 314 config->irq = L4_INVALID_CAP; 315 } 316 } 317 318 /* Discard any uninitiated thread. */ 319 320 void ipc_server_discard_thread(ipc_server_config_type *config) 321 { 322 if (config->config_thread && l4_is_valid_cap(config->thread)) 323 { 324 ipc_cap_free_um(config->thread); 325 config->thread = L4_INVALID_CAP; 326 } 327 } 328 329 /* Initialise a server configuration. */ 330 331 void ipc_server_init_config(ipc_server_config_type *config) 332 { 333 /* No object references defined. */ 334 335 config->handler_obj = NULL; 336 config->finaliser_obj = NULL; 337 338 /* Expect no capability items by default. */ 339 340 config->expected_items = 0; 341 342 /* No handler or finaliser defined. */ 343 344 config->handler = NULL; 345 config->finaliser = NULL; 346 347 /* No separate thread for the main loop. */ 348 349 config->config_thread = 0; 350 351 /* Main thread by default with IPC gate to be allocated. */ 352 353 config->thread = l4re_env()->main_thread; 354 config->server = L4_INVALID_CAP; 355 356 /* No notifications and with IRQ to be potentially allocated. */ 357 358 config->notifications = 0; 359 config->irq = L4_INVALID_CAP; 360 } 361 362 /* Initialise and start a server using the given configuration. */ 363 364 long ipc_server_start_config(ipc_server_config_type *config) 365 { 366 long err; 367 368 /* Allocate a new IPC gate if one is not already defined. */ 369 370 if (l4_is_invalid_cap(config->server)) 371 { 372 err = ipc_server_new_for_thread(&config->server, config, config->thread); 373 374 if (err) 375 return err; 376 } 377 378 /* Allocate an IRQ for notifications if requested. */ 379 380 if (config->notifications) 381 { 382 err = ipc_server_apply_irq_for_thread(config->server, &config->irq, config->thread); 383 384 if (err) 385 return err; 386 } 387 388 /* With a separate thread, return the last status value. Otherwise, invoke the 389 main loop. */ 390 391 if (config->config_thread) 392 return L4_EOK; 393 else 394 return (long) ipc_server_start_mainloop(config); 395 } 396 397 /* vim: tabstop=2 expandtab shiftwidth=2 398 */