1 // SPDX-License-Identifier: GPL-2.0 2 #define _GNU_SOURCE 3 #include <sys/sendfile.h> 4 #include <tracefs.h> 5 #include <stdlib.h> 6 #include <unistd.h> 7 #include <errno.h> 8 9 #include "trace.h" 10 #include "utils.h" 11 12 /* 13 * enable_tracer_by_name - enable a tracer on the given instance 14 */ 15 int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer_name) 16 { 17 enum tracefs_tracers tracer; 18 int retval; 19 20 tracer = TRACEFS_TRACER_CUSTOM; 21 22 debug_msg("Enabling %s tracer\n", tracer_name); 23 24 retval = tracefs_tracer_set(inst, tracer, tracer_name); 25 if (retval < 0) { 26 if (errno == ENODEV) 27 err_msg("Tracer %s not found!\n", tracer_name); 28 29 err_msg("Failed to enable the %s tracer\n", tracer_name); 30 return -1; 31 } 32 33 return 0; 34 } 35 36 /* 37 * disable_tracer - set nop tracer to the insta 38 */ 39 void disable_tracer(struct tracefs_instance *inst) 40 { 41 enum tracefs_tracers t = TRACEFS_TRACER_NOP; 42 int retval; 43 44 retval = tracefs_tracer_set(inst, t); 45 if (retval < 0) 46 err_msg("Oops, error disabling tracer\n"); 47 } 48 49 /* 50 * create_instance - create a trace instance with *instance_name 51 */ 52 struct tracefs_instance *create_instance(char *instance_name) 53 { 54 return tracefs_instance_create(instance_name); 55 } 56 57 /* 58 * destroy_instance - remove a trace instance and free the data 59 */ 60 void destroy_instance(struct tracefs_instance *inst) 61 { 62 tracefs_instance_destroy(inst); 63 tracefs_instance_free(inst); 64 } 65 66 /* 67 * save_trace_to_file - save the trace output of the instance to the file 68 */ 69 int save_trace_to_file(struct tracefs_instance *inst, const char *filename) 70 { 71 const char *file = "trace"; 72 mode_t mode = 0644; 73 char buffer[4096]; 74 int out_fd, in_fd; 75 int retval = -1; 76 77 if (!inst || !filename) 78 return 0; 79 80 in_fd = tracefs_instance_file_open(inst, file, O_RDONLY); 81 if (in_fd < 0) { 82 err_msg("Failed to open trace file\n"); 83 return -1; 84 } 85 86 printf(" Saving trace to %s\n", filename); 87 out_fd = creat(filename, mode); 88 if (out_fd < 0) { 89 err_msg("Failed to create output file %s\n", filename); 90 goto out_close_in; 91 } 92 93 do { 94 retval = read(in_fd, buffer, sizeof(buffer)); 95 if (retval <= 0) 96 goto out_close; 97 98 retval = write(out_fd, buffer, retval); 99 if (retval < 0) 100 goto out_close; 101 } while (retval > 0); 102 103 retval = 0; 104 out_close: 105 close(out_fd); 106 out_close_in: 107 close(in_fd); 108 return retval; 109 } 110 111 /* 112 * collect_registered_events - call the existing callback function for the event 113 * 114 * If an event has a registered callback function, call it. 115 * Otherwise, ignore the event. 116 */ 117 int 118 collect_registered_events(struct tep_event *event, struct tep_record *record, 119 int cpu, void *context) 120 { 121 struct trace_instance *trace = context; 122 struct trace_seq *s = trace->seq; 123 124 trace->processed_events++; 125 126 if (!event->handler) 127 return 0; 128 129 event->handler(s, record, event, context); 130 131 return 0; 132 } 133 134 /* 135 * collect_missed_events - record number of missed events 136 * 137 * If rtla cannot keep up with events generated by tracer, events are going 138 * to fall out of the ring buffer. 139 * Collect how many events were missed so it can be reported to the user. 140 */ 141 static int 142 collect_missed_events(struct tep_event *event, struct tep_record *record, 143 int cpu, void *context) 144 { 145 struct trace_instance *trace = context; 146 147 if (trace->missed_events == UINT64_MAX) 148 return 0; 149 150 if (record->missed_events > 0) 151 trace->missed_events += record->missed_events; 152 else 153 /* Events missed but no data on how many */ 154 trace->missed_events = UINT64_MAX; 155 156 return 0; 157 } 158 159 /* 160 * trace_instance_destroy - destroy and free a rtla trace instance 161 */ 162 void trace_instance_destroy(struct trace_instance *trace) 163 { 164 if (trace->inst) { 165 disable_tracer(trace->inst); 166 destroy_instance(trace->inst); 167 trace->inst = NULL; 168 } 169 170 if (trace->seq) { 171 free(trace->seq); 172 trace->seq = NULL; 173 } 174 175 if (trace->tep) { 176 tep_free(trace->tep); 177 trace->tep = NULL; 178 } 179 } 180 181 /* 182 * trace_instance_init - create an rtla trace instance 183 * 184 * It is more than the tracefs instance, as it contains other 185 * things required for the tracing, such as the local events and 186 * a seq file. 187 * 188 * Note that the trace instance is returned disabled. This allows 189 * the tool to apply some other configs, like setting priority 190 * to the kernel threads, before starting generating trace entries. 191 */ 192 int trace_instance_init(struct trace_instance *trace, char *tool_name) 193 { 194 trace->seq = calloc_fatal(1, sizeof(*trace->seq)); 195 196 trace_seq_init(trace->seq); 197 198 trace->inst = create_instance(tool_name); 199 if (!trace->inst) 200 goto out_err; 201 202 trace->tep = tracefs_local_events(NULL); 203 if (!trace->tep) 204 goto out_err; 205 206 /* 207 * Let the main enable the record after setting some other 208 * things such as the priority of the tracer's threads. 209 */ 210 tracefs_trace_off(trace->inst); 211 212 /* 213 * Collect the number of events missed due to tracefs buffer 214 * overflow. 215 */ 216 trace->missed_events = 0; 217 tracefs_follow_missed_events(trace->inst, 218 collect_missed_events, 219 trace); 220 221 trace->processed_events = 0; 222 223 return 0; 224 225 out_err: 226 trace_instance_destroy(trace); 227 return 1; 228 } 229 230 /* 231 * trace_instance_start - start tracing a given rtla instance 232 */ 233 int trace_instance_start(struct trace_instance *trace) 234 { 235 return tracefs_trace_on(trace->inst); 236 } 237 238 /* 239 * trace_instance_stop - stop tracing a given rtla instance 240 */ 241 int trace_instance_stop(struct trace_instance *trace) 242 { 243 return tracefs_trace_off(trace->inst); 244 } 245 246 /* 247 * trace_events_free - free a list of trace events 248 */ 249 static void trace_events_free(struct trace_events *events) 250 { 251 struct trace_events *tevent = events; 252 struct trace_events *free_event; 253 254 while (tevent) { 255 free_event = tevent; 256 257 tevent = tevent->next; 258 259 if (free_event->filter) 260 free(free_event->filter); 261 if (free_event->trigger) 262 free(free_event->trigger); 263 free(free_event->system); 264 free(free_event); 265 } 266 } 267 268 /* 269 * trace_event_alloc - alloc and parse a single trace event 270 */ 271 struct trace_events *trace_event_alloc(const char *event_string) 272 { 273 struct trace_events *tevent; 274 275 tevent = calloc_fatal(1, sizeof(*tevent)); 276 277 tevent->system = strdup_fatal(event_string); 278 279 tevent->event = strstr(tevent->system, ":"); 280 if (tevent->event) { 281 *tevent->event = '\0'; 282 tevent->event = &tevent->event[1]; 283 } 284 285 return tevent; 286 } 287 288 /* 289 * trace_event_add_filter - record an event filter 290 */ 291 void trace_event_add_filter(struct trace_events *event, char *filter) 292 { 293 if (event->filter) 294 free(event->filter); 295 296 event->filter = strdup_fatal(filter); 297 } 298 299 /* 300 * trace_event_add_trigger - record an event trigger action 301 */ 302 void trace_event_add_trigger(struct trace_events *event, char *trigger) 303 { 304 if (event->trigger) 305 free(event->trigger); 306 307 event->trigger = strdup_fatal(trigger); 308 } 309 310 /* 311 * trace_event_disable_filter - disable an event filter 312 */ 313 static void trace_event_disable_filter(struct trace_instance *instance, 314 struct trace_events *tevent) 315 { 316 char filter[MAX_PATH]; 317 int retval; 318 319 if (!tevent->filter) 320 return; 321 322 if (!tevent->filter_enabled) 323 return; 324 325 debug_msg("Disabling %s:%s filter %s\n", tevent->system, 326 tevent->event ? : "*", tevent->filter); 327 328 snprintf(filter, ARRAY_SIZE(filter), "!%s\n", tevent->filter); 329 330 retval = tracefs_event_file_write(instance->inst, tevent->system, 331 tevent->event, "filter", filter); 332 if (retval < 0) 333 err_msg("Error disabling %s:%s filter %s\n", tevent->system, 334 tevent->event ? : "*", tevent->filter); 335 } 336 337 /* 338 * trace_event_save_hist - save the content of an event hist 339 * 340 * If the trigger is a hist: one, save the content of the hist file. 341 */ 342 static void trace_event_save_hist(struct trace_instance *instance, 343 struct trace_events *tevent) 344 { 345 int retval, index, out_fd; 346 mode_t mode = 0644; 347 char path[MAX_PATH]; 348 char *hist; 349 350 if (!tevent) 351 return; 352 353 /* trigger enables hist */ 354 if (!tevent->trigger) 355 return; 356 357 /* is this a hist: trigger? */ 358 retval = strncmp(tevent->trigger, "hist:", strlen("hist:")); 359 if (retval) 360 return; 361 362 snprintf(path, ARRAY_SIZE(path), "%s_%s_hist.txt", tevent->system, tevent->event); 363 364 printf(" Saving event %s:%s hist to %s\n", tevent->system, tevent->event, path); 365 366 out_fd = creat(path, mode); 367 if (out_fd < 0) { 368 err_msg(" Failed to create %s output file\n", path); 369 return; 370 } 371 372 hist = tracefs_event_file_read(instance->inst, tevent->system, tevent->event, "hist", 0); 373 if (!hist) { 374 err_msg(" Failed to read %s:%s hist file\n", tevent->system, tevent->event); 375 goto out_close; 376 } 377 378 index = 0; 379 do { 380 index += write(out_fd, &hist[index], strlen(hist) - index); 381 } while (index < strlen(hist)); 382 383 free(hist); 384 out_close: 385 close(out_fd); 386 } 387 388 /* 389 * trace_event_disable_trigger - disable an event trigger 390 */ 391 static void trace_event_disable_trigger(struct trace_instance *instance, 392 struct trace_events *tevent) 393 { 394 char trigger[MAX_PATH]; 395 int retval; 396 397 if (!tevent->trigger) 398 return; 399 400 if (!tevent->trigger_enabled) 401 return; 402 403 debug_msg("Disabling %s:%s trigger %s\n", tevent->system, 404 tevent->event ? : "*", tevent->trigger); 405 406 trace_event_save_hist(instance, tevent); 407 408 snprintf(trigger, ARRAY_SIZE(trigger), "!%s\n", tevent->trigger); 409 410 retval = tracefs_event_file_write(instance->inst, tevent->system, 411 tevent->event, "trigger", trigger); 412 if (retval < 0) 413 err_msg("Error disabling %s:%s trigger %s\n", tevent->system, 414 tevent->event ? : "*", tevent->trigger); 415 } 416 417 /* 418 * trace_events_disable - disable all trace events 419 */ 420 void trace_events_disable(struct trace_instance *instance, 421 struct trace_events *events) 422 { 423 struct trace_events *tevent = events; 424 425 if (!events) 426 return; 427 428 while (tevent) { 429 debug_msg("Disabling event %s:%s\n", tevent->system, tevent->event ? : "*"); 430 if (tevent->enabled) { 431 trace_event_disable_filter(instance, tevent); 432 trace_event_disable_trigger(instance, tevent); 433 tracefs_event_disable(instance->inst, tevent->system, tevent->event); 434 } 435 436 tevent->enabled = 0; 437 tevent = tevent->next; 438 } 439 } 440 441 /* 442 * trace_event_enable_filter - enable an event filter associated with an event 443 */ 444 static int trace_event_enable_filter(struct trace_instance *instance, 445 struct trace_events *tevent) 446 { 447 char filter[MAX_PATH]; 448 int retval; 449 450 if (!tevent->filter) 451 return 0; 452 453 if (!tevent->event) { 454 err_msg("Filter %s applies only for single events, not for all %s:* events\n", 455 tevent->filter, tevent->system); 456 return 1; 457 } 458 459 snprintf(filter, ARRAY_SIZE(filter), "%s\n", tevent->filter); 460 461 debug_msg("Enabling %s:%s filter %s\n", tevent->system, 462 tevent->event ? : "*", tevent->filter); 463 464 retval = tracefs_event_file_write(instance->inst, tevent->system, 465 tevent->event, "filter", filter); 466 if (retval < 0) { 467 err_msg("Error enabling %s:%s filter %s\n", tevent->system, 468 tevent->event ? : "*", tevent->filter); 469 return 1; 470 } 471 472 tevent->filter_enabled = 1; 473 return 0; 474 } 475 476 /* 477 * trace_event_enable_trigger - enable an event trigger associated with an event 478 */ 479 static int trace_event_enable_trigger(struct trace_instance *instance, 480 struct trace_events *tevent) 481 { 482 char trigger[MAX_PATH]; 483 int retval; 484 485 if (!tevent->trigger) 486 return 0; 487 488 if (!tevent->event) { 489 err_msg("Trigger %s applies only for single events, not for all %s:* events\n", 490 tevent->trigger, tevent->system); 491 return 1; 492 } 493 494 snprintf(trigger, ARRAY_SIZE(trigger), "%s\n", tevent->trigger); 495 496 debug_msg("Enabling %s:%s trigger %s\n", tevent->system, 497 tevent->event ? : "*", tevent->trigger); 498 499 retval = tracefs_event_file_write(instance->inst, tevent->system, 500 tevent->event, "trigger", trigger); 501 if (retval < 0) { 502 err_msg("Error enabling %s:%s trigger %s\n", tevent->system, 503 tevent->event ? : "*", tevent->trigger); 504 return 1; 505 } 506 507 tevent->trigger_enabled = 1; 508 509 return 0; 510 } 511 512 /* 513 * trace_events_enable - enable all events 514 */ 515 int trace_events_enable(struct trace_instance *instance, 516 struct trace_events *events) 517 { 518 struct trace_events *tevent = events; 519 int retval; 520 521 while (tevent) { 522 debug_msg("Enabling event %s:%s\n", tevent->system, tevent->event ? : "*"); 523 retval = tracefs_event_enable(instance->inst, tevent->system, tevent->event); 524 if (retval < 0) { 525 err_msg("Error enabling event %s:%s\n", tevent->system, 526 tevent->event ? : "*"); 527 return 1; 528 } 529 530 retval = trace_event_enable_filter(instance, tevent); 531 if (retval) 532 return 1; 533 534 retval = trace_event_enable_trigger(instance, tevent); 535 if (retval) 536 return 1; 537 538 tevent->enabled = 1; 539 tevent = tevent->next; 540 } 541 542 return 0; 543 } 544 545 /* 546 * trace_events_destroy - disable and free all trace events 547 */ 548 void trace_events_destroy(struct trace_instance *instance, 549 struct trace_events *events) 550 { 551 if (!events) 552 return; 553 554 trace_events_disable(instance, events); 555 trace_events_free(events); 556 } 557 558 /* 559 * trace_set_buffer_size - set the per-cpu tracing buffer size. 560 */ 561 int trace_set_buffer_size(struct trace_instance *trace, int size) 562 { 563 int retval; 564 565 debug_msg("Setting trace buffer size to %d Kb\n", size); 566 retval = tracefs_instance_set_buffer_size(trace->inst, size, -1); 567 if (retval) 568 err_msg("Error setting trace buffer size\n"); 569 570 return retval; 571 } 572