1 // SPDX-License-Identifier: GPL-2.0 2 #define _GNU_SOURCE 3 #include <sys/sendfile.h> 4 #include <tracefs.h> 5 #include <signal.h> 6 #include <stdlib.h> 7 #include <unistd.h> 8 #include <errno.h> 9 10 #include "trace.h" 11 #include "utils.h" 12 13 /* 14 * enable_tracer_by_name - enable a tracer on the given instance 15 */ 16 int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer_name) 17 { 18 enum tracefs_tracers tracer; 19 int retval; 20 21 tracer = TRACEFS_TRACER_CUSTOM; 22 23 debug_msg("Enabling %s tracer\n", tracer_name); 24 25 retval = tracefs_tracer_set(inst, tracer, tracer_name); 26 if (retval < 0) { 27 if (errno == ENODEV) 28 err_msg("Tracer %s not found!\n", tracer_name); 29 30 err_msg("Failed to enable the %s tracer\n", tracer_name); 31 return -1; 32 } 33 34 return 0; 35 } 36 37 /* 38 * disable_tracer - set nop tracer to the insta 39 */ 40 void disable_tracer(struct tracefs_instance *inst) 41 { 42 enum tracefs_tracers t = TRACEFS_TRACER_NOP; 43 int retval; 44 45 retval = tracefs_tracer_set(inst, t); 46 if (retval < 0) 47 err_msg("Oops, error disabling tracer\n"); 48 } 49 50 /* 51 * create_instance - create a trace instance with *instance_name 52 */ 53 struct tracefs_instance *create_instance(char *instance_name) 54 { 55 return tracefs_instance_create(instance_name); 56 } 57 58 /* 59 * destroy_instance - remove a trace instance and free the data 60 */ 61 void destroy_instance(struct tracefs_instance *inst) 62 { 63 tracefs_instance_destroy(inst); 64 tracefs_instance_free(inst); 65 } 66 67 /* 68 * save_trace_to_file - save the trace output of the instance to the file 69 */ 70 int save_trace_to_file(struct tracefs_instance *inst, const char *filename) 71 { 72 const char *file = "trace"; 73 mode_t mode = 0644; 74 char buffer[4096]; 75 int out_fd, in_fd; 76 int retval = -1; 77 78 in_fd = tracefs_instance_file_open(inst, file, O_RDONLY); 79 if (in_fd < 0) { 80 err_msg("Failed to open trace file\n"); 81 return -1; 82 } 83 84 out_fd = creat(filename, mode); 85 if (out_fd < 0) { 86 err_msg("Failed to create output file %s\n", filename); 87 goto out_close_in; 88 } 89 90 do { 91 retval = read(in_fd, buffer, sizeof(buffer)); 92 if (retval <= 0) 93 goto out_close; 94 95 retval = write(out_fd, buffer, retval); 96 if (retval < 0) 97 goto out_close; 98 } while (retval > 0); 99 100 retval = 0; 101 out_close: 102 close(out_fd); 103 out_close_in: 104 close(in_fd); 105 return retval; 106 } 107 108 /* 109 * collect_registered_events - call the existing callback function for the event 110 * 111 * If an event has a registered callback function, call it. 112 * Otherwise, ignore the event. 113 */ 114 int 115 collect_registered_events(struct tep_event *event, struct tep_record *record, 116 int cpu, void *context) 117 { 118 struct trace_instance *trace = context; 119 struct trace_seq *s = trace->seq; 120 121 if (!event->handler) 122 return 0; 123 124 event->handler(s, record, event, context); 125 126 return 0; 127 } 128 129 /* 130 * trace_instance_destroy - destroy and free a rtla trace instance 131 */ 132 void trace_instance_destroy(struct trace_instance *trace) 133 { 134 if (trace->inst) { 135 disable_tracer(trace->inst); 136 destroy_instance(trace->inst); 137 trace->inst = NULL; 138 } 139 140 if (trace->seq) { 141 free(trace->seq); 142 trace->seq = NULL; 143 } 144 145 if (trace->tep) { 146 tep_free(trace->tep); 147 trace->tep = NULL; 148 } 149 } 150 151 /* 152 * trace_instance_init - create an rtla trace instance 153 * 154 * It is more than the tracefs instance, as it contains other 155 * things required for the tracing, such as the local events and 156 * a seq file. 157 * 158 * Note that the trace instance is returned disabled. This allows 159 * the tool to apply some other configs, like setting priority 160 * to the kernel threads, before starting generating trace entries. 161 */ 162 int trace_instance_init(struct trace_instance *trace, char *tool_name) 163 { 164 trace->seq = calloc(1, sizeof(*trace->seq)); 165 if (!trace->seq) 166 goto out_err; 167 168 trace_seq_init(trace->seq); 169 170 trace->inst = create_instance(tool_name); 171 if (!trace->inst) 172 goto out_err; 173 174 trace->tep = tracefs_local_events(NULL); 175 if (!trace->tep) 176 goto out_err; 177 178 /* 179 * Let the main enable the record after setting some other 180 * things such as the priority of the tracer's threads. 181 */ 182 tracefs_trace_off(trace->inst); 183 184 return 0; 185 186 out_err: 187 trace_instance_destroy(trace); 188 return 1; 189 } 190 191 /* 192 * trace_instance_start - start tracing a given rtla instance 193 */ 194 int trace_instance_start(struct trace_instance *trace) 195 { 196 return tracefs_trace_on(trace->inst); 197 } 198 199 /* 200 * trace_events_free - free a list of trace events 201 */ 202 static void trace_events_free(struct trace_events *events) 203 { 204 struct trace_events *tevent = events; 205 struct trace_events *free_event; 206 207 while (tevent) { 208 free_event = tevent; 209 210 tevent = tevent->next; 211 212 if (free_event->filter) 213 free(free_event->filter); 214 if (free_event->trigger) 215 free(free_event->trigger); 216 free(free_event->system); 217 free(free_event); 218 } 219 } 220 221 /* 222 * trace_event_alloc - alloc and parse a single trace event 223 */ 224 struct trace_events *trace_event_alloc(const char *event_string) 225 { 226 struct trace_events *tevent; 227 228 tevent = calloc(1, sizeof(*tevent)); 229 if (!tevent) 230 return NULL; 231 232 tevent->system = strdup(event_string); 233 if (!tevent->system) { 234 free(tevent); 235 return NULL; 236 } 237 238 tevent->event = strstr(tevent->system, ":"); 239 if (tevent->event) { 240 *tevent->event = '\0'; 241 tevent->event = &tevent->event[1]; 242 } 243 244 return tevent; 245 } 246 247 /* 248 * trace_event_add_filter - record an event filter 249 */ 250 int trace_event_add_filter(struct trace_events *event, char *filter) 251 { 252 if (event->filter) 253 free(event->filter); 254 255 event->filter = strdup(filter); 256 if (!event->filter) 257 return 1; 258 259 return 0; 260 } 261 262 /* 263 * trace_event_add_trigger - record an event trigger action 264 */ 265 int trace_event_add_trigger(struct trace_events *event, char *trigger) 266 { 267 if (event->trigger) 268 free(event->trigger); 269 270 event->trigger = strdup(trigger); 271 if (!event->trigger) 272 return 1; 273 274 return 0; 275 } 276 277 /* 278 * trace_event_disable_filter - disable an event filter 279 */ 280 static void trace_event_disable_filter(struct trace_instance *instance, 281 struct trace_events *tevent) 282 { 283 char filter[1024]; 284 int retval; 285 286 if (!tevent->filter) 287 return; 288 289 if (!tevent->filter_enabled) 290 return; 291 292 debug_msg("Disabling %s:%s filter %s\n", tevent->system, 293 tevent->event ? : "*", tevent->filter); 294 295 snprintf(filter, 1024, "!%s\n", tevent->filter); 296 297 retval = tracefs_event_file_write(instance->inst, tevent->system, 298 tevent->event, "filter", filter); 299 if (retval < 0) 300 err_msg("Error disabling %s:%s filter %s\n", tevent->system, 301 tevent->event ? : "*", tevent->filter); 302 } 303 304 /* 305 * trace_event_save_hist - save the content of an event hist 306 * 307 * If the trigger is a hist: one, save the content of the hist file. 308 */ 309 static void trace_event_save_hist(struct trace_instance *instance, 310 struct trace_events *tevent) 311 { 312 int retval, index, out_fd; 313 mode_t mode = 0644; 314 char path[1024]; 315 char *hist; 316 317 if (!tevent) 318 return; 319 320 /* trigger enables hist */ 321 if (!tevent->trigger) 322 return; 323 324 /* is this a hist: trigger? */ 325 retval = strncmp(tevent->trigger, "hist:", strlen("hist:")); 326 if (retval) 327 return; 328 329 snprintf(path, 1024, "%s_%s_hist.txt", tevent->system, tevent->event); 330 331 printf(" Saving event %s:%s hist to %s\n", tevent->system, tevent->event, path); 332 333 out_fd = creat(path, mode); 334 if (out_fd < 0) { 335 err_msg(" Failed to create %s output file\n", path); 336 return; 337 } 338 339 hist = tracefs_event_file_read(instance->inst, tevent->system, tevent->event, "hist", 0); 340 if (!hist) { 341 err_msg(" Failed to read %s:%s hist file\n", tevent->system, tevent->event); 342 goto out_close; 343 } 344 345 index = 0; 346 do { 347 index += write(out_fd, &hist[index], strlen(hist) - index); 348 } while (index < strlen(hist)); 349 350 free(hist); 351 out_close: 352 close(out_fd); 353 } 354 355 /* 356 * trace_event_disable_trigger - disable an event trigger 357 */ 358 static void trace_event_disable_trigger(struct trace_instance *instance, 359 struct trace_events *tevent) 360 { 361 char trigger[1024]; 362 int retval; 363 364 if (!tevent->trigger) 365 return; 366 367 if (!tevent->trigger_enabled) 368 return; 369 370 debug_msg("Disabling %s:%s trigger %s\n", tevent->system, 371 tevent->event ? : "*", tevent->trigger); 372 373 trace_event_save_hist(instance, tevent); 374 375 snprintf(trigger, 1024, "!%s\n", tevent->trigger); 376 377 retval = tracefs_event_file_write(instance->inst, tevent->system, 378 tevent->event, "trigger", trigger); 379 if (retval < 0) 380 err_msg("Error disabling %s:%s trigger %s\n", tevent->system, 381 tevent->event ? : "*", tevent->trigger); 382 } 383 384 /* 385 * trace_events_disable - disable all trace events 386 */ 387 void trace_events_disable(struct trace_instance *instance, 388 struct trace_events *events) 389 { 390 struct trace_events *tevent = events; 391 392 if (!events) 393 return; 394 395 while (tevent) { 396 debug_msg("Disabling event %s:%s\n", tevent->system, tevent->event ? : "*"); 397 if (tevent->enabled) { 398 trace_event_disable_filter(instance, tevent); 399 trace_event_disable_trigger(instance, tevent); 400 tracefs_event_disable(instance->inst, tevent->system, tevent->event); 401 } 402 403 tevent->enabled = 0; 404 tevent = tevent->next; 405 } 406 } 407 408 /* 409 * trace_event_enable_filter - enable an event filter associated with an event 410 */ 411 static int trace_event_enable_filter(struct trace_instance *instance, 412 struct trace_events *tevent) 413 { 414 char filter[1024]; 415 int retval; 416 417 if (!tevent->filter) 418 return 0; 419 420 if (!tevent->event) { 421 err_msg("Filter %s applies only for single events, not for all %s:* events\n", 422 tevent->filter, tevent->system); 423 return 1; 424 } 425 426 snprintf(filter, 1024, "%s\n", tevent->filter); 427 428 debug_msg("Enabling %s:%s filter %s\n", tevent->system, 429 tevent->event ? : "*", tevent->filter); 430 431 retval = tracefs_event_file_write(instance->inst, tevent->system, 432 tevent->event, "filter", filter); 433 if (retval < 0) { 434 err_msg("Error enabling %s:%s filter %s\n", tevent->system, 435 tevent->event ? : "*", tevent->filter); 436 return 1; 437 } 438 439 tevent->filter_enabled = 1; 440 return 0; 441 } 442 443 /* 444 * trace_event_enable_trigger - enable an event trigger associated with an event 445 */ 446 static int trace_event_enable_trigger(struct trace_instance *instance, 447 struct trace_events *tevent) 448 { 449 char trigger[1024]; 450 int retval; 451 452 if (!tevent->trigger) 453 return 0; 454 455 if (!tevent->event) { 456 err_msg("Trigger %s applies only for single events, not for all %s:* events\n", 457 tevent->trigger, tevent->system); 458 return 1; 459 } 460 461 snprintf(trigger, 1024, "%s\n", tevent->trigger); 462 463 debug_msg("Enabling %s:%s trigger %s\n", tevent->system, 464 tevent->event ? : "*", tevent->trigger); 465 466 retval = tracefs_event_file_write(instance->inst, tevent->system, 467 tevent->event, "trigger", trigger); 468 if (retval < 0) { 469 err_msg("Error enabling %s:%s trigger %s\n", tevent->system, 470 tevent->event ? : "*", tevent->trigger); 471 return 1; 472 } 473 474 tevent->trigger_enabled = 1; 475 476 return 0; 477 } 478 479 /* 480 * trace_events_enable - enable all events 481 */ 482 int trace_events_enable(struct trace_instance *instance, 483 struct trace_events *events) 484 { 485 struct trace_events *tevent = events; 486 int retval; 487 488 while (tevent) { 489 debug_msg("Enabling event %s:%s\n", tevent->system, tevent->event ? : "*"); 490 retval = tracefs_event_enable(instance->inst, tevent->system, tevent->event); 491 if (retval < 0) { 492 err_msg("Error enabling event %s:%s\n", tevent->system, 493 tevent->event ? : "*"); 494 return 1; 495 } 496 497 retval = trace_event_enable_filter(instance, tevent); 498 if (retval) 499 return 1; 500 501 retval = trace_event_enable_trigger(instance, tevent); 502 if (retval) 503 return 1; 504 505 tevent->enabled = 1; 506 tevent = tevent->next; 507 } 508 509 return 0; 510 } 511 512 /* 513 * trace_events_destroy - disable and free all trace events 514 */ 515 void trace_events_destroy(struct trace_instance *instance, 516 struct trace_events *events) 517 { 518 if (!events) 519 return; 520 521 trace_events_disable(instance, events); 522 trace_events_free(events); 523 } 524 525 int trace_is_off(struct trace_instance *tool, struct trace_instance *trace) 526 { 527 /* 528 * The tool instance is always present, it is the one used to collect 529 * data. 530 */ 531 if (!tracefs_trace_is_on(tool->inst)) 532 return 1; 533 534 /* 535 * The trace instance is only enabled when -t is set. IOW, when the system 536 * is tracing. 537 */ 538 if (trace && !tracefs_trace_is_on(trace->inst)) 539 return 1; 540 541 return 0; 542 } 543