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 */
enable_tracer_by_name(struct tracefs_instance * inst,const char * tracer_name)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 */
disable_tracer(struct tracefs_instance * inst)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 */
create_instance(char * instance_name)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 */
destroy_instance(struct tracefs_instance * inst)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 */
save_trace_to_file(struct tracefs_instance * inst,const char * filename)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
collect_registered_events(struct tep_event * event,struct tep_record * record,int cpu,void * context)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 */
trace_instance_destroy(struct trace_instance * trace)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 */
trace_instance_init(struct trace_instance * trace,char * tool_name)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 */
trace_instance_start(struct trace_instance * trace)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 */
trace_events_free(struct trace_events * events)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 */
trace_event_alloc(const char * event_string)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 */
trace_event_add_filter(struct trace_events * event,char * filter)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 */
trace_event_add_trigger(struct trace_events * event,char * trigger)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 */
trace_event_disable_filter(struct trace_instance * instance,struct trace_events * tevent)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 */
trace_event_save_hist(struct trace_instance * instance,struct trace_events * tevent)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 */
trace_event_disable_trigger(struct trace_instance * instance,struct trace_events * tevent)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 */
trace_events_disable(struct trace_instance * instance,struct trace_events * events)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 */
trace_event_enable_filter(struct trace_instance * instance,struct trace_events * tevent)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 */
trace_event_enable_trigger(struct trace_instance * instance,struct trace_events * tevent)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 */
trace_events_enable(struct trace_instance * instance,struct trace_events * events)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 */
trace_events_destroy(struct trace_instance * instance,struct trace_events * events)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
trace_is_off(struct trace_instance * tool,struct trace_instance * trace)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