1 /* 2 * Server binding/registration. 3 * 4 * Copyright (C) 2018, 2019, 2020, 2021 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_config(&config); 170 config.expected_items = expected_items; 171 config.handler = handler; 172 config.handler_obj = handler_obj; 173 174 return ipc_server_start_config(&config); 175 } 176 177 /* A server main loop with no endpoint deletion detection. */ 178 179 long ipc_server_loop(int expected_items, ipc_server_config_type *config) 180 { 181 return ipc_server_managed_loop(expected_items, config, L4_INVALID_CAP); 182 } 183 184 /* A server main loop handling endpoint deletion for an IPC gate dedicated to 185 a particular object within its own thread. */ 186 187 long ipc_server_managed_loop(int expected_items, ipc_server_config_type *config, 188 l4_cap_idx_t irq) 189 { 190 ipc_message_t msg; 191 l4_umword_t label, irq_label = (l4_umword_t) irq; 192 193 /* Permit other endpoints by dynamically interpreting the label. */ 194 195 ipc_server_config_type *config_from_label; 196 197 /* Declare the extent to which capabilities are expected in messages. */ 198 199 long err = ipc_message_expect(&msg, expected_items); 200 201 if (err) 202 return err; 203 204 /* Unmask the interrupt. */ 205 206 if (l4_is_valid_cap(irq)) 207 ipc_init_irq(irq); 208 209 /* Wait for an incoming message. */ 210 211 while (1) 212 { 213 ipc_message_wait(&msg, &label); 214 215 /* Clear lower label bits. */ 216 217 label = label & ~3UL; 218 219 /* Ignore erroneous messages. */ 220 221 if (l4_ipc_error(msg.tag, l4_utcb())) 222 continue; 223 224 /* Message involves the IPC gate itself. */ 225 226 if (label != irq_label) 227 { 228 config_from_label = (ipc_server_config_type *) label; 229 config_from_label->handler(&msg, config_from_label->handler_obj); 230 } 231 232 /* Message involves the IRQ or a termination condition occurred. */ 233 234 if ((label == irq_label) || msg.terminating) 235 break; 236 } 237 238 /* Free expected capabilities. */ 239 240 ipc_message_free(&msg); 241 242 return L4_EOK; 243 } 244 245 /* A pthread-compatible mainloop initiation function. */ 246 247 void *ipc_server_start_mainloop(void *data) 248 { 249 ipc_server_config_type *config = (ipc_server_config_type *) data; 250 251 long err = ipc_server_managed_loop(config->expected_items, config, 252 config->irq); 253 254 if (config->finaliser != NULL) 255 config->finaliser(config); 256 257 return (void *) err; 258 } 259 260 /* Wait for an incoming message via an IPC gate dedicated to a particular 261 object within its own thread. */ 262 263 l4_msgtag_t ipc_server_wait(l4_umword_t id) 264 { 265 l4_umword_t label; 266 l4_msgtag_t tag; 267 268 /* Ignore errors and messages not intended for the identified gate. */ 269 270 do tag = l4_ipc_wait(l4_utcb(), &label, L4_IPC_NEVER); 271 while (l4_ipc_error(tag, l4_utcb()) || (label & ~3UL) != id); 272 273 return tag; 274 } 275 276 277 278 /* Finalise a server configuration. */ 279 280 void ipc_server_finalise_config(ipc_server_config_type *config) 281 { 282 if (l4_is_valid_cap(config->server)) 283 { 284 ipc_cap_free_um(config->server); 285 config->server = L4_INVALID_CAP; 286 } 287 288 if (l4_is_valid_cap(config->irq)) 289 { 290 ipc_cap_free_um(config->irq); 291 config->irq = L4_INVALID_CAP; 292 } 293 } 294 295 /* Discard any thread created but not initiated. */ 296 297 void ipc_server_discard_thread(ipc_server_config_type *config) 298 { 299 if (config->new_thread && l4_is_valid_cap(config->thread)) 300 { 301 ipc_cap_free_um(config->thread); 302 config->thread = L4_INVALID_CAP; 303 } 304 } 305 306 /* Initialise a server configuration. */ 307 308 void ipc_server_init_config(ipc_server_config_type *config) 309 { 310 /* No object references defined. */ 311 312 config->handler_obj = NULL; 313 config->finaliser_obj = NULL; 314 315 /* Expect no capability items by default. */ 316 317 config->expected_items = 0; 318 319 /* No handler or finaliser defined. */ 320 321 config->handler = NULL; 322 config->finaliser = NULL; 323 324 /* No new thread for the mainloop. */ 325 326 config->new_thread = 0; 327 328 /* Main thread by default with IPC gate to be allocated. */ 329 330 config->thread = l4re_env()->main_thread; 331 config->server = L4_INVALID_CAP; 332 333 /* No notifications and with IRQ to be potentially allocated. */ 334 335 config->notifications = 0; 336 config->irq = L4_INVALID_CAP; 337 } 338 339 /* Initialise and start a server using the given configuration. */ 340 341 long ipc_server_start_config(ipc_server_config_type *config) 342 { 343 long err; 344 345 /* Allocate a new IPC gate if one is not already defined. */ 346 347 if (l4_is_invalid_cap(config->server)) 348 { 349 err = ipc_server_new_for_thread(&config->server, config, config->thread); 350 351 if (err) 352 return err; 353 } 354 355 /* Allocate an IRQ for notifications if requested. */ 356 357 if (config->notifications) 358 { 359 err = ipc_server_apply_irq_for_thread(config->server, &config->irq, config->thread); 360 361 if (err) 362 return err; 363 } 364 365 /* With a new thread, return the last status value. Otherwise, invoke the main 366 loop. */ 367 368 if (config->new_thread) 369 return L4_EOK; 370 else 371 return (long) ipc_server_start_mainloop(config); 372 }