1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * trace_events_synth - synthetic trace events
4 *
5 * Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
6 */
7
8 #include <linux/module.h>
9 #include <linux/kallsyms.h>
10 #include <linux/security.h>
11 #include <linux/mutex.h>
12 #include <linux/slab.h>
13 #include <linux/stacktrace.h>
14 #include <linux/rculist.h>
15 #include <linux/tracefs.h>
16
17 /* for gfp flag names */
18 #include <linux/trace_events.h>
19 #include <trace/events/mmflags.h>
20 #include "trace_probe.h"
21 #include "trace_probe_kernel.h"
22
23 #include "trace_synth.h"
24
25 #undef ERRORS
26 #define ERRORS \
27 C(BAD_NAME, "Illegal name"), \
28 C(INVALID_CMD, "Command must be of the form: <name> field[;field] ..."),\
29 C(INVALID_DYN_CMD, "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
30 C(EVENT_EXISTS, "Event already exists"), \
31 C(TOO_MANY_FIELDS, "Too many fields"), \
32 C(INCOMPLETE_TYPE, "Incomplete type"), \
33 C(INVALID_TYPE, "Invalid type"), \
34 C(INVALID_FIELD, "Invalid field"), \
35 C(INVALID_ARRAY_SPEC, "Invalid array specification"),
36
37 #undef C
38 #define C(a, b) SYNTH_ERR_##a
39
40 enum { ERRORS };
41
42 #undef C
43 #define C(a, b) b
44
45 static const char *err_text[] = { ERRORS };
46
47 static DEFINE_MUTEX(lastcmd_mutex);
48 static char *last_cmd;
49
errpos(const char * str)50 static int errpos(const char *str)
51 {
52 int ret = 0;
53
54 mutex_lock(&lastcmd_mutex);
55 if (!str || !last_cmd)
56 goto out;
57
58 ret = err_pos(last_cmd, str);
59 out:
60 mutex_unlock(&lastcmd_mutex);
61 return ret;
62 }
63
last_cmd_set(const char * str)64 static void last_cmd_set(const char *str)
65 {
66 if (!str)
67 return;
68
69 mutex_lock(&lastcmd_mutex);
70 kfree(last_cmd);
71 last_cmd = kstrdup(str, GFP_KERNEL);
72 mutex_unlock(&lastcmd_mutex);
73 }
74
synth_err(u8 err_type,u16 err_pos)75 static void synth_err(u8 err_type, u16 err_pos)
76 {
77 mutex_lock(&lastcmd_mutex);
78 if (!last_cmd)
79 goto out;
80
81 tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
82 err_type, err_pos);
83 out:
84 mutex_unlock(&lastcmd_mutex);
85 }
86
87 static int create_synth_event(const char *raw_command);
88 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
89 static int synth_event_release(struct dyn_event *ev);
90 static bool synth_event_is_busy(struct dyn_event *ev);
91 static bool synth_event_match(const char *system, const char *event,
92 int argc, const char **argv, struct dyn_event *ev);
93
94 static struct dyn_event_operations synth_event_ops = {
95 .create = create_synth_event,
96 .show = synth_event_show,
97 .is_busy = synth_event_is_busy,
98 .free = synth_event_release,
99 .match = synth_event_match,
100 };
101
is_synth_event(struct dyn_event * ev)102 static bool is_synth_event(struct dyn_event *ev)
103 {
104 return ev->ops == &synth_event_ops;
105 }
106
to_synth_event(struct dyn_event * ev)107 static struct synth_event *to_synth_event(struct dyn_event *ev)
108 {
109 return container_of(ev, struct synth_event, devent);
110 }
111
synth_event_is_busy(struct dyn_event * ev)112 static bool synth_event_is_busy(struct dyn_event *ev)
113 {
114 struct synth_event *event = to_synth_event(ev);
115
116 return event->ref != 0;
117 }
118
synth_event_match(const char * system,const char * event,int argc,const char ** argv,struct dyn_event * ev)119 static bool synth_event_match(const char *system, const char *event,
120 int argc, const char **argv, struct dyn_event *ev)
121 {
122 struct synth_event *sev = to_synth_event(ev);
123
124 return strcmp(sev->name, event) == 0 &&
125 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
126 }
127
128 struct synth_trace_event {
129 struct trace_entry ent;
130 u64 fields[];
131 };
132
synth_event_define_fields(struct trace_event_call * call)133 static int synth_event_define_fields(struct trace_event_call *call)
134 {
135 struct synth_trace_event trace;
136 int offset = offsetof(typeof(trace), fields);
137 struct synth_event *event = call->data;
138 unsigned int i, size, n_u64;
139 char *name, *type;
140 bool is_signed;
141 int ret = 0;
142
143 for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
144 size = event->fields[i]->size;
145 is_signed = event->fields[i]->is_signed;
146 type = event->fields[i]->type;
147 name = event->fields[i]->name;
148 ret = trace_define_field(call, type, name, offset, size,
149 is_signed, FILTER_OTHER);
150 if (ret)
151 break;
152
153 event->fields[i]->offset = n_u64;
154
155 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
156 offset += STR_VAR_LEN_MAX;
157 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
158 } else {
159 offset += sizeof(u64);
160 n_u64++;
161 }
162 }
163
164 event->n_u64 = n_u64;
165
166 return ret;
167 }
168
synth_field_signed(char * type)169 static bool synth_field_signed(char *type)
170 {
171 if (str_has_prefix(type, "u"))
172 return false;
173 if (strcmp(type, "gfp_t") == 0)
174 return false;
175
176 return true;
177 }
178
synth_field_is_string(char * type)179 static int synth_field_is_string(char *type)
180 {
181 if (strstr(type, "char[") != NULL)
182 return true;
183
184 return false;
185 }
186
synth_field_is_stack(char * type)187 static int synth_field_is_stack(char *type)
188 {
189 if (strstr(type, "long[") != NULL)
190 return true;
191
192 return false;
193 }
194
synth_field_string_size(char * type)195 static int synth_field_string_size(char *type)
196 {
197 char buf[4], *end, *start;
198 unsigned int len;
199 int size, err;
200
201 start = strstr(type, "char[");
202 if (start == NULL)
203 return -EINVAL;
204 start += sizeof("char[") - 1;
205
206 end = strchr(type, ']');
207 if (!end || end < start || type + strlen(type) > end + 1)
208 return -EINVAL;
209
210 len = end - start;
211 if (len > 3)
212 return -EINVAL;
213
214 if (len == 0)
215 return 0; /* variable-length string */
216
217 strncpy(buf, start, len);
218 buf[len] = '\0';
219
220 err = kstrtouint(buf, 0, &size);
221 if (err)
222 return err;
223
224 if (size > STR_VAR_LEN_MAX)
225 return -EINVAL;
226
227 return size;
228 }
229
synth_field_size(char * type)230 static int synth_field_size(char *type)
231 {
232 int size = 0;
233
234 if (strcmp(type, "s64") == 0)
235 size = sizeof(s64);
236 else if (strcmp(type, "u64") == 0)
237 size = sizeof(u64);
238 else if (strcmp(type, "s32") == 0)
239 size = sizeof(s32);
240 else if (strcmp(type, "u32") == 0)
241 size = sizeof(u32);
242 else if (strcmp(type, "s16") == 0)
243 size = sizeof(s16);
244 else if (strcmp(type, "u16") == 0)
245 size = sizeof(u16);
246 else if (strcmp(type, "s8") == 0)
247 size = sizeof(s8);
248 else if (strcmp(type, "u8") == 0)
249 size = sizeof(u8);
250 else if (strcmp(type, "char") == 0)
251 size = sizeof(char);
252 else if (strcmp(type, "unsigned char") == 0)
253 size = sizeof(unsigned char);
254 else if (strcmp(type, "int") == 0)
255 size = sizeof(int);
256 else if (strcmp(type, "unsigned int") == 0)
257 size = sizeof(unsigned int);
258 else if (strcmp(type, "long") == 0)
259 size = sizeof(long);
260 else if (strcmp(type, "unsigned long") == 0)
261 size = sizeof(unsigned long);
262 else if (strcmp(type, "bool") == 0)
263 size = sizeof(bool);
264 else if (strcmp(type, "pid_t") == 0)
265 size = sizeof(pid_t);
266 else if (strcmp(type, "gfp_t") == 0)
267 size = sizeof(gfp_t);
268 else if (synth_field_is_string(type))
269 size = synth_field_string_size(type);
270 else if (synth_field_is_stack(type))
271 size = 0;
272
273 return size;
274 }
275
synth_field_fmt(char * type)276 static const char *synth_field_fmt(char *type)
277 {
278 const char *fmt = "%llu";
279
280 if (strcmp(type, "s64") == 0)
281 fmt = "%lld";
282 else if (strcmp(type, "u64") == 0)
283 fmt = "%llu";
284 else if (strcmp(type, "s32") == 0)
285 fmt = "%d";
286 else if (strcmp(type, "u32") == 0)
287 fmt = "%u";
288 else if (strcmp(type, "s16") == 0)
289 fmt = "%d";
290 else if (strcmp(type, "u16") == 0)
291 fmt = "%u";
292 else if (strcmp(type, "s8") == 0)
293 fmt = "%d";
294 else if (strcmp(type, "u8") == 0)
295 fmt = "%u";
296 else if (strcmp(type, "char") == 0)
297 fmt = "%d";
298 else if (strcmp(type, "unsigned char") == 0)
299 fmt = "%u";
300 else if (strcmp(type, "int") == 0)
301 fmt = "%d";
302 else if (strcmp(type, "unsigned int") == 0)
303 fmt = "%u";
304 else if (strcmp(type, "long") == 0)
305 fmt = "%ld";
306 else if (strcmp(type, "unsigned long") == 0)
307 fmt = "%lu";
308 else if (strcmp(type, "bool") == 0)
309 fmt = "%d";
310 else if (strcmp(type, "pid_t") == 0)
311 fmt = "%d";
312 else if (strcmp(type, "gfp_t") == 0)
313 fmt = "%x";
314 else if (synth_field_is_string(type))
315 fmt = "%.*s";
316 else if (synth_field_is_stack(type))
317 fmt = "%s";
318
319 return fmt;
320 }
321
print_synth_event_num_val(struct trace_seq * s,char * print_fmt,char * name,int size,u64 val,char * space)322 static void print_synth_event_num_val(struct trace_seq *s,
323 char *print_fmt, char *name,
324 int size, u64 val, char *space)
325 {
326 switch (size) {
327 case 1:
328 trace_seq_printf(s, print_fmt, name, (u8)val, space);
329 break;
330
331 case 2:
332 trace_seq_printf(s, print_fmt, name, (u16)val, space);
333 break;
334
335 case 4:
336 trace_seq_printf(s, print_fmt, name, (u32)val, space);
337 break;
338
339 default:
340 trace_seq_printf(s, print_fmt, name, val, space);
341 break;
342 }
343 }
344
print_synth_event(struct trace_iterator * iter,int flags,struct trace_event * event)345 static enum print_line_t print_synth_event(struct trace_iterator *iter,
346 int flags,
347 struct trace_event *event)
348 {
349 struct trace_array *tr = iter->tr;
350 struct trace_seq *s = &iter->seq;
351 struct synth_trace_event *entry;
352 struct synth_event *se;
353 unsigned int i, n_u64;
354 char print_fmt[32];
355 const char *fmt;
356
357 entry = (struct synth_trace_event *)iter->ent;
358 se = container_of(event, struct synth_event, call.event);
359
360 trace_seq_printf(s, "%s: ", se->name);
361
362 for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
363 if (trace_seq_has_overflowed(s))
364 goto end;
365
366 fmt = synth_field_fmt(se->fields[i]->type);
367
368 /* parameter types */
369 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
370 trace_seq_printf(s, "%s ", fmt);
371
372 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
373
374 /* parameter values */
375 if (se->fields[i]->is_string) {
376 if (se->fields[i]->is_dynamic) {
377 u32 offset, data_offset;
378 char *str_field;
379
380 offset = (u32)entry->fields[n_u64];
381 data_offset = offset & 0xffff;
382
383 str_field = (char *)entry + data_offset;
384
385 trace_seq_printf(s, print_fmt, se->fields[i]->name,
386 STR_VAR_LEN_MAX,
387 str_field,
388 i == se->n_fields - 1 ? "" : " ");
389 n_u64++;
390 } else {
391 trace_seq_printf(s, print_fmt, se->fields[i]->name,
392 STR_VAR_LEN_MAX,
393 (char *)&entry->fields[n_u64],
394 i == se->n_fields - 1 ? "" : " ");
395 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
396 }
397 } else if (se->fields[i]->is_stack) {
398 u32 offset, data_offset, len;
399 unsigned long *p, *end;
400
401 offset = (u32)entry->fields[n_u64];
402 data_offset = offset & 0xffff;
403 len = offset >> 16;
404
405 p = (void *)entry + data_offset;
406 end = (void *)p + len - (sizeof(long) - 1);
407
408 trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
409
410 for (; *p && p < end; p++)
411 trace_seq_printf(s, "=> %pS\n", (void *)*p);
412 n_u64++;
413
414 } else {
415 struct trace_print_flags __flags[] = {
416 __def_gfpflag_names, {-1, NULL} };
417 char *space = (i == se->n_fields - 1 ? "" : " ");
418
419 print_synth_event_num_val(s, print_fmt,
420 se->fields[i]->name,
421 se->fields[i]->size,
422 entry->fields[n_u64],
423 space);
424
425 if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
426 trace_seq_puts(s, " (");
427 trace_print_flags_seq(s, "|",
428 entry->fields[n_u64],
429 __flags);
430 trace_seq_putc(s, ')');
431 }
432 n_u64++;
433 }
434 }
435 end:
436 trace_seq_putc(s, '\n');
437
438 return trace_handle_return(s);
439 }
440
441 static struct trace_event_functions synth_event_funcs = {
442 .trace = print_synth_event
443 };
444
trace_string(struct synth_trace_event * entry,struct synth_event * event,char * str_val,bool is_dynamic,unsigned int data_size,unsigned int * n_u64)445 static unsigned int trace_string(struct synth_trace_event *entry,
446 struct synth_event *event,
447 char *str_val,
448 bool is_dynamic,
449 unsigned int data_size,
450 unsigned int *n_u64)
451 {
452 unsigned int len = 0;
453 char *str_field;
454 int ret;
455
456 if (is_dynamic) {
457 u32 data_offset;
458
459 data_offset = offsetof(typeof(*entry), fields);
460 data_offset += event->n_u64 * sizeof(u64);
461 data_offset += data_size;
462
463 len = kern_fetch_store_strlen((unsigned long)str_val);
464
465 data_offset |= len << 16;
466 *(u32 *)&entry->fields[*n_u64] = data_offset;
467
468 ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
469
470 (*n_u64)++;
471 } else {
472 str_field = (char *)&entry->fields[*n_u64];
473
474 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
475 if ((unsigned long)str_val < TASK_SIZE)
476 ret = strncpy_from_user_nofault(str_field, (const void __user *)str_val, STR_VAR_LEN_MAX);
477 else
478 #endif
479 ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
480
481 if (ret < 0)
482 strcpy(str_field, FAULT_STRING);
483
484 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
485 }
486
487 return len;
488 }
489
trace_stack(struct synth_trace_event * entry,struct synth_event * event,long * stack,unsigned int data_size,unsigned int * n_u64)490 static unsigned int trace_stack(struct synth_trace_event *entry,
491 struct synth_event *event,
492 long *stack,
493 unsigned int data_size,
494 unsigned int *n_u64)
495 {
496 unsigned int len;
497 u32 data_offset;
498 void *data_loc;
499
500 data_offset = struct_size(entry, fields, event->n_u64);
501 data_offset += data_size;
502
503 for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
504 if (!stack[len])
505 break;
506 }
507
508 /* Include the zero'd element if it fits */
509 if (len < HIST_STACKTRACE_DEPTH)
510 len++;
511
512 len *= sizeof(long);
513
514 /* Find the dynamic section to copy the stack into. */
515 data_loc = (void *)entry + data_offset;
516 memcpy(data_loc, stack, len);
517
518 /* Fill in the field that holds the offset/len combo */
519 data_offset |= len << 16;
520 *(u32 *)&entry->fields[*n_u64] = data_offset;
521
522 (*n_u64)++;
523
524 return len;
525 }
526
trace_event_raw_event_synth(void * __data,u64 * var_ref_vals,unsigned int * var_ref_idx)527 static notrace void trace_event_raw_event_synth(void *__data,
528 u64 *var_ref_vals,
529 unsigned int *var_ref_idx)
530 {
531 unsigned int i, n_u64, val_idx, len, data_size = 0;
532 struct trace_event_file *trace_file = __data;
533 struct synth_trace_event *entry;
534 struct trace_event_buffer fbuffer;
535 struct trace_buffer *buffer;
536 struct synth_event *event;
537 int fields_size = 0;
538
539 event = trace_file->event_call->data;
540
541 if (trace_trigger_soft_disabled(trace_file))
542 return;
543
544 fields_size = event->n_u64 * sizeof(u64);
545
546 for (i = 0; i < event->n_dynamic_fields; i++) {
547 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
548 char *str_val;
549
550 val_idx = var_ref_idx[field_pos];
551 str_val = (char *)(long)var_ref_vals[val_idx];
552
553 len = kern_fetch_store_strlen((unsigned long)str_val);
554
555 fields_size += len;
556 }
557
558 /*
559 * Avoid ring buffer recursion detection, as this event
560 * is being performed within another event.
561 */
562 buffer = trace_file->tr->array_buffer.buffer;
563 ring_buffer_nest_start(buffer);
564
565 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
566 sizeof(*entry) + fields_size);
567 if (!entry)
568 goto out;
569
570 for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
571 val_idx = var_ref_idx[i];
572 if (event->fields[i]->is_string) {
573 char *str_val = (char *)(long)var_ref_vals[val_idx];
574
575 len = trace_string(entry, event, str_val,
576 event->fields[i]->is_dynamic,
577 data_size, &n_u64);
578 data_size += len; /* only dynamic string increments */
579 } else if (event->fields[i]->is_stack) {
580 long *stack = (long *)(long)var_ref_vals[val_idx];
581
582 len = trace_stack(entry, event, stack,
583 data_size, &n_u64);
584 data_size += len;
585 } else {
586 struct synth_field *field = event->fields[i];
587 u64 val = var_ref_vals[val_idx];
588
589 switch (field->size) {
590 case 1:
591 *(u8 *)&entry->fields[n_u64] = (u8)val;
592 break;
593
594 case 2:
595 *(u16 *)&entry->fields[n_u64] = (u16)val;
596 break;
597
598 case 4:
599 *(u32 *)&entry->fields[n_u64] = (u32)val;
600 break;
601
602 default:
603 entry->fields[n_u64] = val;
604 break;
605 }
606 n_u64++;
607 }
608 }
609
610 trace_event_buffer_commit(&fbuffer);
611 out:
612 ring_buffer_nest_end(buffer);
613 }
614
free_synth_event_print_fmt(struct trace_event_call * call)615 static void free_synth_event_print_fmt(struct trace_event_call *call)
616 {
617 if (call) {
618 kfree(call->print_fmt);
619 call->print_fmt = NULL;
620 }
621 }
622
__set_synth_event_print_fmt(struct synth_event * event,char * buf,int len)623 static int __set_synth_event_print_fmt(struct synth_event *event,
624 char *buf, int len)
625 {
626 const char *fmt;
627 int pos = 0;
628 int i;
629
630 /* When len=0, we just calculate the needed length */
631 #define LEN_OR_ZERO (len ? len - pos : 0)
632
633 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
634 for (i = 0; i < event->n_fields; i++) {
635 fmt = synth_field_fmt(event->fields[i]->type);
636 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
637 event->fields[i]->name, fmt,
638 i == event->n_fields - 1 ? "" : ", ");
639 }
640 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
641
642 for (i = 0; i < event->n_fields; i++) {
643 if (event->fields[i]->is_string &&
644 event->fields[i]->is_dynamic)
645 pos += snprintf(buf + pos, LEN_OR_ZERO,
646 ", __get_str(%s)", event->fields[i]->name);
647 else if (event->fields[i]->is_stack)
648 pos += snprintf(buf + pos, LEN_OR_ZERO,
649 ", __get_stacktrace(%s)", event->fields[i]->name);
650 else
651 pos += snprintf(buf + pos, LEN_OR_ZERO,
652 ", REC->%s", event->fields[i]->name);
653 }
654
655 #undef LEN_OR_ZERO
656
657 /* return the length of print_fmt */
658 return pos;
659 }
660
set_synth_event_print_fmt(struct trace_event_call * call)661 static int set_synth_event_print_fmt(struct trace_event_call *call)
662 {
663 struct synth_event *event = call->data;
664 char *print_fmt;
665 int len;
666
667 /* First: called with 0 length to calculate the needed length */
668 len = __set_synth_event_print_fmt(event, NULL, 0);
669
670 print_fmt = kmalloc(len + 1, GFP_KERNEL);
671 if (!print_fmt)
672 return -ENOMEM;
673
674 /* Second: actually write the @print_fmt */
675 __set_synth_event_print_fmt(event, print_fmt, len + 1);
676 call->print_fmt = print_fmt;
677
678 return 0;
679 }
680
free_synth_field(struct synth_field * field)681 static void free_synth_field(struct synth_field *field)
682 {
683 kfree(field->type);
684 kfree(field->name);
685 kfree(field);
686 }
687
check_field_version(const char * prefix,const char * field_type,const char * field_name)688 static int check_field_version(const char *prefix, const char *field_type,
689 const char *field_name)
690 {
691 /*
692 * For backward compatibility, the old synthetic event command
693 * format did not require semicolons, and in order to not
694 * break user space, that old format must still work. If a new
695 * feature is added, then the format that uses the new feature
696 * will be required to have semicolons, as nothing that uses
697 * the old format would be using the new, yet to be created,
698 * feature. When a new feature is added, this will detect it,
699 * and return a number greater than 1, and require the format
700 * to use semicolons.
701 */
702 return 1;
703 }
704
parse_synth_field(int argc,char ** argv,int * consumed,int * field_version)705 static struct synth_field *parse_synth_field(int argc, char **argv,
706 int *consumed, int *field_version)
707 {
708 const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
709 struct synth_field *field;
710 int len, ret = -ENOMEM;
711 struct seq_buf s;
712 ssize_t size;
713
714 if (!strcmp(field_type, "unsigned")) {
715 if (argc < 3) {
716 synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
717 return ERR_PTR(-EINVAL);
718 }
719 prefix = "unsigned ";
720 field_type = argv[1];
721 field_name = argv[2];
722 *consumed += 3;
723 } else {
724 field_name = argv[1];
725 *consumed += 2;
726 }
727
728 if (!field_name) {
729 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
730 return ERR_PTR(-EINVAL);
731 }
732
733 *field_version = check_field_version(prefix, field_type, field_name);
734
735 field = kzalloc(sizeof(*field), GFP_KERNEL);
736 if (!field)
737 return ERR_PTR(-ENOMEM);
738
739 len = strlen(field_name);
740 array = strchr(field_name, '[');
741 if (array)
742 len -= strlen(array);
743
744 field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
745 if (!field->name)
746 goto free;
747
748 if (!is_good_name(field->name)) {
749 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
750 ret = -EINVAL;
751 goto free;
752 }
753
754 len = strlen(field_type) + 1;
755
756 if (array)
757 len += strlen(array);
758
759 if (prefix)
760 len += strlen(prefix);
761
762 field->type = kzalloc(len, GFP_KERNEL);
763 if (!field->type)
764 goto free;
765
766 seq_buf_init(&s, field->type, len);
767 if (prefix)
768 seq_buf_puts(&s, prefix);
769 seq_buf_puts(&s, field_type);
770 if (array)
771 seq_buf_puts(&s, array);
772 if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
773 goto free;
774
775 s.buffer[s.len] = '\0';
776
777 size = synth_field_size(field->type);
778 if (size < 0) {
779 if (array)
780 synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
781 else
782 synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
783 ret = -EINVAL;
784 goto free;
785 } else if (size == 0) {
786 if (synth_field_is_string(field->type) ||
787 synth_field_is_stack(field->type)) {
788 char *type;
789
790 len = sizeof("__data_loc ") + strlen(field->type) + 1;
791 type = kzalloc(len, GFP_KERNEL);
792 if (!type)
793 goto free;
794
795 seq_buf_init(&s, type, len);
796 seq_buf_puts(&s, "__data_loc ");
797 seq_buf_puts(&s, field->type);
798
799 if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
800 goto free;
801 s.buffer[s.len] = '\0';
802
803 kfree(field->type);
804 field->type = type;
805
806 field->is_dynamic = true;
807 size = sizeof(u64);
808 } else {
809 synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
810 ret = -EINVAL;
811 goto free;
812 }
813 }
814 field->size = size;
815
816 if (synth_field_is_string(field->type))
817 field->is_string = true;
818 else if (synth_field_is_stack(field->type))
819 field->is_stack = true;
820
821 field->is_signed = synth_field_signed(field->type);
822 out:
823 return field;
824 free:
825 free_synth_field(field);
826 field = ERR_PTR(ret);
827 goto out;
828 }
829
free_synth_tracepoint(struct tracepoint * tp)830 static void free_synth_tracepoint(struct tracepoint *tp)
831 {
832 if (!tp)
833 return;
834
835 kfree(tp->name);
836 kfree(tp);
837 }
838
alloc_synth_tracepoint(char * name)839 static struct tracepoint *alloc_synth_tracepoint(char *name)
840 {
841 struct tracepoint *tp;
842
843 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
844 if (!tp)
845 return ERR_PTR(-ENOMEM);
846
847 tp->name = kstrdup(name, GFP_KERNEL);
848 if (!tp->name) {
849 kfree(tp);
850 return ERR_PTR(-ENOMEM);
851 }
852
853 return tp;
854 }
855
find_synth_event(const char * name)856 struct synth_event *find_synth_event(const char *name)
857 {
858 struct dyn_event *pos;
859 struct synth_event *event;
860
861 for_each_dyn_event(pos) {
862 if (!is_synth_event(pos))
863 continue;
864 event = to_synth_event(pos);
865 if (strcmp(event->name, name) == 0)
866 return event;
867 }
868
869 return NULL;
870 }
871
872 static struct trace_event_fields synth_event_fields_array[] = {
873 { .type = TRACE_FUNCTION_TYPE,
874 .define_fields = synth_event_define_fields },
875 {}
876 };
877
register_synth_event(struct synth_event * event)878 static int register_synth_event(struct synth_event *event)
879 {
880 struct trace_event_call *call = &event->call;
881 int ret = 0;
882
883 event->call.class = &event->class;
884 event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
885 if (!event->class.system) {
886 ret = -ENOMEM;
887 goto out;
888 }
889
890 event->tp = alloc_synth_tracepoint(event->name);
891 if (IS_ERR(event->tp)) {
892 ret = PTR_ERR(event->tp);
893 event->tp = NULL;
894 goto out;
895 }
896
897 INIT_LIST_HEAD(&call->class->fields);
898 call->event.funcs = &synth_event_funcs;
899 call->class->fields_array = synth_event_fields_array;
900
901 ret = register_trace_event(&call->event);
902 if (!ret) {
903 ret = -ENODEV;
904 goto out;
905 }
906 call->flags = TRACE_EVENT_FL_TRACEPOINT;
907 call->class->reg = trace_event_reg;
908 call->class->probe = trace_event_raw_event_synth;
909 call->data = event;
910 call->tp = event->tp;
911
912 ret = trace_add_event_call(call);
913 if (ret) {
914 pr_warn("Failed to register synthetic event: %s\n",
915 trace_event_name(call));
916 goto err;
917 }
918
919 ret = set_synth_event_print_fmt(call);
920 /* unregister_trace_event() will be called inside */
921 if (ret < 0)
922 trace_remove_event_call(call);
923 out:
924 return ret;
925 err:
926 unregister_trace_event(&call->event);
927 goto out;
928 }
929
unregister_synth_event(struct synth_event * event)930 static int unregister_synth_event(struct synth_event *event)
931 {
932 struct trace_event_call *call = &event->call;
933 int ret;
934
935 ret = trace_remove_event_call(call);
936
937 return ret;
938 }
939
free_synth_event(struct synth_event * event)940 static void free_synth_event(struct synth_event *event)
941 {
942 unsigned int i;
943
944 if (!event)
945 return;
946
947 for (i = 0; i < event->n_fields; i++)
948 free_synth_field(event->fields[i]);
949
950 kfree(event->fields);
951 kfree(event->dynamic_fields);
952 kfree(event->name);
953 kfree(event->class.system);
954 free_synth_tracepoint(event->tp);
955 free_synth_event_print_fmt(&event->call);
956 kfree(event);
957 }
958
alloc_synth_event(const char * name,int n_fields,struct synth_field ** fields)959 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
960 struct synth_field **fields)
961 {
962 unsigned int i, j, n_dynamic_fields = 0;
963 struct synth_event *event;
964
965 event = kzalloc(sizeof(*event), GFP_KERNEL);
966 if (!event) {
967 event = ERR_PTR(-ENOMEM);
968 goto out;
969 }
970
971 event->name = kstrdup(name, GFP_KERNEL);
972 if (!event->name) {
973 kfree(event);
974 event = ERR_PTR(-ENOMEM);
975 goto out;
976 }
977
978 event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
979 if (!event->fields) {
980 free_synth_event(event);
981 event = ERR_PTR(-ENOMEM);
982 goto out;
983 }
984
985 for (i = 0; i < n_fields; i++)
986 if (fields[i]->is_dynamic)
987 n_dynamic_fields++;
988
989 if (n_dynamic_fields) {
990 event->dynamic_fields = kcalloc(n_dynamic_fields,
991 sizeof(*event->dynamic_fields),
992 GFP_KERNEL);
993 if (!event->dynamic_fields) {
994 free_synth_event(event);
995 event = ERR_PTR(-ENOMEM);
996 goto out;
997 }
998 }
999
1000 dyn_event_init(&event->devent, &synth_event_ops);
1001
1002 for (i = 0, j = 0; i < n_fields; i++) {
1003 fields[i]->field_pos = i;
1004 event->fields[i] = fields[i];
1005
1006 if (fields[i]->is_dynamic)
1007 event->dynamic_fields[j++] = fields[i];
1008 }
1009 event->n_dynamic_fields = j;
1010 event->n_fields = n_fields;
1011 out:
1012 return event;
1013 }
1014
synth_event_check_arg_fn(void * data)1015 static int synth_event_check_arg_fn(void *data)
1016 {
1017 struct dynevent_arg_pair *arg_pair = data;
1018 int size;
1019
1020 size = synth_field_size((char *)arg_pair->lhs);
1021 if (size == 0) {
1022 if (strstr((char *)arg_pair->lhs, "["))
1023 return 0;
1024 }
1025
1026 return size ? 0 : -EINVAL;
1027 }
1028
1029 /**
1030 * synth_event_add_field - Add a new field to a synthetic event cmd
1031 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1032 * @type: The type of the new field to add
1033 * @name: The name of the new field to add
1034 *
1035 * Add a new field to a synthetic event cmd object. Field ordering is in
1036 * the same order the fields are added.
1037 *
1038 * See synth_field_size() for available types. If field_name contains
1039 * [n] the field is considered to be an array.
1040 *
1041 * Return: 0 if successful, error otherwise.
1042 */
synth_event_add_field(struct dynevent_cmd * cmd,const char * type,const char * name)1043 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1044 const char *name)
1045 {
1046 struct dynevent_arg_pair arg_pair;
1047 int ret;
1048
1049 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1050 return -EINVAL;
1051
1052 if (!type || !name)
1053 return -EINVAL;
1054
1055 dynevent_arg_pair_init(&arg_pair, 0, ';');
1056
1057 arg_pair.lhs = type;
1058 arg_pair.rhs = name;
1059
1060 ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1061 if (ret)
1062 return ret;
1063
1064 if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1065 ret = -EINVAL;
1066
1067 return ret;
1068 }
1069 EXPORT_SYMBOL_GPL(synth_event_add_field);
1070
1071 /**
1072 * synth_event_add_field_str - Add a new field to a synthetic event cmd
1073 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1074 * @type_name: The type and name of the new field to add, as a single string
1075 *
1076 * Add a new field to a synthetic event cmd object, as a single
1077 * string. The @type_name string is expected to be of the form 'type
1078 * name', which will be appended by ';'. No sanity checking is done -
1079 * what's passed in is assumed to already be well-formed. Field
1080 * ordering is in the same order the fields are added.
1081 *
1082 * See synth_field_size() for available types. If field_name contains
1083 * [n] the field is considered to be an array.
1084 *
1085 * Return: 0 if successful, error otherwise.
1086 */
synth_event_add_field_str(struct dynevent_cmd * cmd,const char * type_name)1087 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1088 {
1089 struct dynevent_arg arg;
1090 int ret;
1091
1092 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1093 return -EINVAL;
1094
1095 if (!type_name)
1096 return -EINVAL;
1097
1098 dynevent_arg_init(&arg, ';');
1099
1100 arg.str = type_name;
1101
1102 ret = dynevent_arg_add(cmd, &arg, NULL);
1103 if (ret)
1104 return ret;
1105
1106 if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1107 ret = -EINVAL;
1108
1109 return ret;
1110 }
1111 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1112
1113 /**
1114 * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1115 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1116 * @fields: An array of type/name field descriptions
1117 * @n_fields: The number of field descriptions contained in the fields array
1118 *
1119 * Add a new set of fields to a synthetic event cmd object. The event
1120 * fields that will be defined for the event should be passed in as an
1121 * array of struct synth_field_desc, and the number of elements in the
1122 * array passed in as n_fields. Field ordering will retain the
1123 * ordering given in the fields array.
1124 *
1125 * See synth_field_size() for available types. If field_name contains
1126 * [n] the field is considered to be an array.
1127 *
1128 * Return: 0 if successful, error otherwise.
1129 */
synth_event_add_fields(struct dynevent_cmd * cmd,struct synth_field_desc * fields,unsigned int n_fields)1130 int synth_event_add_fields(struct dynevent_cmd *cmd,
1131 struct synth_field_desc *fields,
1132 unsigned int n_fields)
1133 {
1134 unsigned int i;
1135 int ret = 0;
1136
1137 for (i = 0; i < n_fields; i++) {
1138 if (fields[i].type == NULL || fields[i].name == NULL) {
1139 ret = -EINVAL;
1140 break;
1141 }
1142
1143 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1144 if (ret)
1145 break;
1146 }
1147
1148 return ret;
1149 }
1150 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1151
1152 /**
1153 * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1154 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1155 * @name: The name of the synthetic event
1156 * @mod: The module creating the event, NULL if not created from a module
1157 * @args: Variable number of arg (pairs), one pair for each field
1158 *
1159 * NOTE: Users normally won't want to call this function directly, but
1160 * rather use the synth_event_gen_cmd_start() wrapper, which
1161 * automatically adds a NULL to the end of the arg list. If this
1162 * function is used directly, make sure the last arg in the variable
1163 * arg list is NULL.
1164 *
1165 * Generate a synthetic event command to be executed by
1166 * synth_event_gen_cmd_end(). This function can be used to generate
1167 * the complete command or only the first part of it; in the latter
1168 * case, synth_event_add_field(), synth_event_add_field_str(), or
1169 * synth_event_add_fields() can be used to add more fields following
1170 * this.
1171 *
1172 * There should be an even number variable args, each pair consisting
1173 * of a type followed by a field name.
1174 *
1175 * See synth_field_size() for available types. If field_name contains
1176 * [n] the field is considered to be an array.
1177 *
1178 * Return: 0 if successful, error otherwise.
1179 */
__synth_event_gen_cmd_start(struct dynevent_cmd * cmd,const char * name,struct module * mod,...)1180 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1181 struct module *mod, ...)
1182 {
1183 struct dynevent_arg arg;
1184 va_list args;
1185 int ret;
1186
1187 cmd->event_name = name;
1188 cmd->private_data = mod;
1189
1190 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1191 return -EINVAL;
1192
1193 dynevent_arg_init(&arg, 0);
1194 arg.str = name;
1195 ret = dynevent_arg_add(cmd, &arg, NULL);
1196 if (ret)
1197 return ret;
1198
1199 va_start(args, mod);
1200 for (;;) {
1201 const char *type, *name;
1202
1203 type = va_arg(args, const char *);
1204 if (!type)
1205 break;
1206 name = va_arg(args, const char *);
1207 if (!name)
1208 break;
1209
1210 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1211 ret = -EINVAL;
1212 break;
1213 }
1214
1215 ret = synth_event_add_field(cmd, type, name);
1216 if (ret)
1217 break;
1218 }
1219 va_end(args);
1220
1221 return ret;
1222 }
1223 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1224
1225 /**
1226 * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1227 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1228 * @name: The name of the synthetic event
1229 * @fields: An array of type/name field descriptions
1230 * @n_fields: The number of field descriptions contained in the fields array
1231 *
1232 * Generate a synthetic event command to be executed by
1233 * synth_event_gen_cmd_end(). This function can be used to generate
1234 * the complete command or only the first part of it; in the latter
1235 * case, synth_event_add_field(), synth_event_add_field_str(), or
1236 * synth_event_add_fields() can be used to add more fields following
1237 * this.
1238 *
1239 * The event fields that will be defined for the event should be
1240 * passed in as an array of struct synth_field_desc, and the number of
1241 * elements in the array passed in as n_fields. Field ordering will
1242 * retain the ordering given in the fields array.
1243 *
1244 * See synth_field_size() for available types. If field_name contains
1245 * [n] the field is considered to be an array.
1246 *
1247 * Return: 0 if successful, error otherwise.
1248 */
synth_event_gen_cmd_array_start(struct dynevent_cmd * cmd,const char * name,struct module * mod,struct synth_field_desc * fields,unsigned int n_fields)1249 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1250 struct module *mod,
1251 struct synth_field_desc *fields,
1252 unsigned int n_fields)
1253 {
1254 struct dynevent_arg arg;
1255 unsigned int i;
1256 int ret = 0;
1257
1258 cmd->event_name = name;
1259 cmd->private_data = mod;
1260
1261 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1262 return -EINVAL;
1263
1264 if (n_fields > SYNTH_FIELDS_MAX)
1265 return -EINVAL;
1266
1267 dynevent_arg_init(&arg, 0);
1268 arg.str = name;
1269 ret = dynevent_arg_add(cmd, &arg, NULL);
1270 if (ret)
1271 return ret;
1272
1273 for (i = 0; i < n_fields; i++) {
1274 if (fields[i].type == NULL || fields[i].name == NULL)
1275 return -EINVAL;
1276
1277 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1278 if (ret)
1279 break;
1280 }
1281
1282 return ret;
1283 }
1284 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1285
__create_synth_event(const char * name,const char * raw_fields)1286 static int __create_synth_event(const char *name, const char *raw_fields)
1287 {
1288 char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1289 struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1290 int consumed, cmd_version = 1, n_fields_this_loop;
1291 int i, argc, n_fields = 0, ret = 0;
1292 struct synth_event *event = NULL;
1293
1294 /*
1295 * Argument syntax:
1296 * - Add synthetic event: <event_name> field[;field] ...
1297 * - Remove synthetic event: !<event_name> field[;field] ...
1298 * where 'field' = type field_name
1299 */
1300
1301 if (name[0] == '\0') {
1302 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1303 return -EINVAL;
1304 }
1305
1306 if (!is_good_name(name)) {
1307 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1308 return -EINVAL;
1309 }
1310
1311 mutex_lock(&event_mutex);
1312
1313 event = find_synth_event(name);
1314 if (event) {
1315 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1316 ret = -EEXIST;
1317 goto err;
1318 }
1319
1320 tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1321 if (!tmp_fields) {
1322 ret = -ENOMEM;
1323 goto err;
1324 }
1325
1326 while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1327 argv = argv_split(GFP_KERNEL, field_str, &argc);
1328 if (!argv) {
1329 ret = -ENOMEM;
1330 goto err;
1331 }
1332
1333 if (!argc) {
1334 argv_free(argv);
1335 continue;
1336 }
1337
1338 n_fields_this_loop = 0;
1339 consumed = 0;
1340 while (argc > consumed) {
1341 int field_version;
1342
1343 field = parse_synth_field(argc - consumed,
1344 argv + consumed, &consumed,
1345 &field_version);
1346 if (IS_ERR(field)) {
1347 ret = PTR_ERR(field);
1348 goto err_free_arg;
1349 }
1350
1351 /*
1352 * Track the highest version of any field we
1353 * found in the command.
1354 */
1355 if (field_version > cmd_version)
1356 cmd_version = field_version;
1357
1358 /*
1359 * Now sort out what is and isn't valid for
1360 * each supported version.
1361 *
1362 * If we see more than 1 field per loop, it
1363 * means we have multiple fields between
1364 * semicolons, and that's something we no
1365 * longer support in a version 2 or greater
1366 * command.
1367 */
1368 if (cmd_version > 1 && n_fields_this_loop >= 1) {
1369 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1370 ret = -EINVAL;
1371 goto err_free_arg;
1372 }
1373
1374 if (n_fields == SYNTH_FIELDS_MAX) {
1375 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1376 ret = -EINVAL;
1377 goto err_free_arg;
1378 }
1379 fields[n_fields++] = field;
1380
1381 n_fields_this_loop++;
1382 }
1383 argv_free(argv);
1384
1385 if (consumed < argc) {
1386 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1387 ret = -EINVAL;
1388 goto err;
1389 }
1390
1391 }
1392
1393 if (n_fields == 0) {
1394 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1395 ret = -EINVAL;
1396 goto err;
1397 }
1398
1399 event = alloc_synth_event(name, n_fields, fields);
1400 if (IS_ERR(event)) {
1401 ret = PTR_ERR(event);
1402 event = NULL;
1403 goto err;
1404 }
1405 ret = register_synth_event(event);
1406 if (!ret)
1407 dyn_event_add(&event->devent, &event->call);
1408 else
1409 free_synth_event(event);
1410 out:
1411 mutex_unlock(&event_mutex);
1412
1413 kfree(saved_fields);
1414
1415 return ret;
1416 err_free_arg:
1417 argv_free(argv);
1418 err:
1419 for (i = 0; i < n_fields; i++)
1420 free_synth_field(fields[i]);
1421
1422 goto out;
1423 }
1424
1425 /**
1426 * synth_event_create - Create a new synthetic event
1427 * @name: The name of the new synthetic event
1428 * @fields: An array of type/name field descriptions
1429 * @n_fields: The number of field descriptions contained in the fields array
1430 * @mod: The module creating the event, NULL if not created from a module
1431 *
1432 * Create a new synthetic event with the given name under the
1433 * trace/events/synthetic/ directory. The event fields that will be
1434 * defined for the event should be passed in as an array of struct
1435 * synth_field_desc, and the number elements in the array passed in as
1436 * n_fields. Field ordering will retain the ordering given in the
1437 * fields array.
1438 *
1439 * If the new synthetic event is being created from a module, the mod
1440 * param must be non-NULL. This will ensure that the trace buffer
1441 * won't contain unreadable events.
1442 *
1443 * The new synth event should be deleted using synth_event_delete()
1444 * function. The new synthetic event can be generated from modules or
1445 * other kernel code using trace_synth_event() and related functions.
1446 *
1447 * Return: 0 if successful, error otherwise.
1448 */
synth_event_create(const char * name,struct synth_field_desc * fields,unsigned int n_fields,struct module * mod)1449 int synth_event_create(const char *name, struct synth_field_desc *fields,
1450 unsigned int n_fields, struct module *mod)
1451 {
1452 struct dynevent_cmd cmd;
1453 char *buf;
1454 int ret;
1455
1456 buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1457 if (!buf)
1458 return -ENOMEM;
1459
1460 synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1461
1462 ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1463 fields, n_fields);
1464 if (ret)
1465 goto out;
1466
1467 ret = synth_event_gen_cmd_end(&cmd);
1468 out:
1469 kfree(buf);
1470
1471 return ret;
1472 }
1473 EXPORT_SYMBOL_GPL(synth_event_create);
1474
destroy_synth_event(struct synth_event * se)1475 static int destroy_synth_event(struct synth_event *se)
1476 {
1477 int ret;
1478
1479 if (se->ref)
1480 return -EBUSY;
1481
1482 if (trace_event_dyn_busy(&se->call))
1483 return -EBUSY;
1484
1485 ret = unregister_synth_event(se);
1486 if (!ret) {
1487 dyn_event_remove(&se->devent);
1488 free_synth_event(se);
1489 }
1490
1491 return ret;
1492 }
1493
1494 /**
1495 * synth_event_delete - Delete a synthetic event
1496 * @event_name: The name of the new synthetic event
1497 *
1498 * Delete a synthetic event that was created with synth_event_create().
1499 *
1500 * Return: 0 if successful, error otherwise.
1501 */
synth_event_delete(const char * event_name)1502 int synth_event_delete(const char *event_name)
1503 {
1504 struct synth_event *se = NULL;
1505 struct module *mod = NULL;
1506 int ret = -ENOENT;
1507
1508 mutex_lock(&event_mutex);
1509 se = find_synth_event(event_name);
1510 if (se) {
1511 mod = se->mod;
1512 ret = destroy_synth_event(se);
1513 }
1514 mutex_unlock(&event_mutex);
1515
1516 if (mod) {
1517 /*
1518 * It is safest to reset the ring buffer if the module
1519 * being unloaded registered any events that were
1520 * used. The only worry is if a new module gets
1521 * loaded, and takes on the same id as the events of
1522 * this module. When printing out the buffer, traced
1523 * events left over from this module may be passed to
1524 * the new module events and unexpected results may
1525 * occur.
1526 */
1527 tracing_reset_all_online_cpus();
1528 }
1529
1530 return ret;
1531 }
1532 EXPORT_SYMBOL_GPL(synth_event_delete);
1533
check_command(const char * raw_command)1534 static int check_command(const char *raw_command)
1535 {
1536 char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1537 int argc, ret = 0;
1538
1539 cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1540 if (!cmd)
1541 return -ENOMEM;
1542
1543 name_and_field = strsep(&cmd, ";");
1544 if (!name_and_field) {
1545 ret = -EINVAL;
1546 goto free;
1547 }
1548
1549 if (name_and_field[0] == '!')
1550 goto free;
1551
1552 argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1553 if (!argv) {
1554 ret = -ENOMEM;
1555 goto free;
1556 }
1557 argv_free(argv);
1558
1559 if (argc < 3)
1560 ret = -EINVAL;
1561 free:
1562 kfree(saved_cmd);
1563
1564 return ret;
1565 }
1566
create_or_delete_synth_event(const char * raw_command)1567 static int create_or_delete_synth_event(const char *raw_command)
1568 {
1569 char *name = NULL, *fields, *p;
1570 int ret = 0;
1571
1572 raw_command = skip_spaces(raw_command);
1573 if (raw_command[0] == '\0')
1574 return ret;
1575
1576 last_cmd_set(raw_command);
1577
1578 ret = check_command(raw_command);
1579 if (ret) {
1580 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1581 return ret;
1582 }
1583
1584 p = strpbrk(raw_command, " \t");
1585 if (!p && raw_command[0] != '!') {
1586 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1587 ret = -EINVAL;
1588 goto free;
1589 }
1590
1591 name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1592 if (!name)
1593 return -ENOMEM;
1594
1595 if (name[0] == '!') {
1596 ret = synth_event_delete(name + 1);
1597 goto free;
1598 }
1599
1600 fields = skip_spaces(p);
1601
1602 ret = __create_synth_event(name, fields);
1603 free:
1604 kfree(name);
1605
1606 return ret;
1607 }
1608
synth_event_run_command(struct dynevent_cmd * cmd)1609 static int synth_event_run_command(struct dynevent_cmd *cmd)
1610 {
1611 struct synth_event *se;
1612 int ret;
1613
1614 ret = create_or_delete_synth_event(cmd->seq.buffer);
1615 if (ret)
1616 return ret;
1617
1618 se = find_synth_event(cmd->event_name);
1619 if (WARN_ON(!se))
1620 return -ENOENT;
1621
1622 se->mod = cmd->private_data;
1623
1624 return ret;
1625 }
1626
1627 /**
1628 * synth_event_cmd_init - Initialize a synthetic event command object
1629 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1630 * @buf: A pointer to the buffer used to build the command
1631 * @maxlen: The length of the buffer passed in @buf
1632 *
1633 * Initialize a synthetic event command object. Use this before
1634 * calling any of the other dyenvent_cmd functions.
1635 */
synth_event_cmd_init(struct dynevent_cmd * cmd,char * buf,int maxlen)1636 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1637 {
1638 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1639 synth_event_run_command);
1640 }
1641 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1642
1643 static inline int
__synth_event_trace_init(struct trace_event_file * file,struct synth_event_trace_state * trace_state)1644 __synth_event_trace_init(struct trace_event_file *file,
1645 struct synth_event_trace_state *trace_state)
1646 {
1647 int ret = 0;
1648
1649 memset(trace_state, '\0', sizeof(*trace_state));
1650
1651 /*
1652 * Normal event tracing doesn't get called at all unless the
1653 * ENABLED bit is set (which attaches the probe thus allowing
1654 * this code to be called, etc). Because this is called
1655 * directly by the user, we don't have that but we still need
1656 * to honor not logging when disabled. For the iterated
1657 * trace case, we save the enabled state upon start and just
1658 * ignore the following data calls.
1659 */
1660 if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1661 trace_trigger_soft_disabled(file)) {
1662 trace_state->disabled = true;
1663 ret = -ENOENT;
1664 goto out;
1665 }
1666
1667 trace_state->event = file->event_call->data;
1668 out:
1669 return ret;
1670 }
1671
1672 static inline int
__synth_event_trace_start(struct trace_event_file * file,struct synth_event_trace_state * trace_state,int dynamic_fields_size)1673 __synth_event_trace_start(struct trace_event_file *file,
1674 struct synth_event_trace_state *trace_state,
1675 int dynamic_fields_size)
1676 {
1677 int entry_size, fields_size = 0;
1678 int ret = 0;
1679
1680 fields_size = trace_state->event->n_u64 * sizeof(u64);
1681 fields_size += dynamic_fields_size;
1682
1683 /*
1684 * Avoid ring buffer recursion detection, as this event
1685 * is being performed within another event.
1686 */
1687 trace_state->buffer = file->tr->array_buffer.buffer;
1688 ring_buffer_nest_start(trace_state->buffer);
1689
1690 entry_size = sizeof(*trace_state->entry) + fields_size;
1691 trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1692 file,
1693 entry_size);
1694 if (!trace_state->entry) {
1695 ring_buffer_nest_end(trace_state->buffer);
1696 ret = -EINVAL;
1697 }
1698
1699 return ret;
1700 }
1701
1702 static inline void
__synth_event_trace_end(struct synth_event_trace_state * trace_state)1703 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1704 {
1705 trace_event_buffer_commit(&trace_state->fbuffer);
1706
1707 ring_buffer_nest_end(trace_state->buffer);
1708 }
1709
1710 /**
1711 * synth_event_trace - Trace a synthetic event
1712 * @file: The trace_event_file representing the synthetic event
1713 * @n_vals: The number of values in vals
1714 * @args: Variable number of args containing the event values
1715 *
1716 * Trace a synthetic event using the values passed in the variable
1717 * argument list.
1718 *
1719 * The argument list should be a list 'n_vals' u64 values. The number
1720 * of vals must match the number of field in the synthetic event, and
1721 * must be in the same order as the synthetic event fields.
1722 *
1723 * All vals should be cast to u64, and string vals are just pointers
1724 * to strings, cast to u64. Strings will be copied into space
1725 * reserved in the event for the string, using these pointers.
1726 *
1727 * Return: 0 on success, err otherwise.
1728 */
synth_event_trace(struct trace_event_file * file,unsigned int n_vals,...)1729 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1730 {
1731 unsigned int i, n_u64, len, data_size = 0;
1732 struct synth_event_trace_state state;
1733 va_list args;
1734 int ret;
1735
1736 ret = __synth_event_trace_init(file, &state);
1737 if (ret) {
1738 if (ret == -ENOENT)
1739 ret = 0; /* just disabled, not really an error */
1740 return ret;
1741 }
1742
1743 if (state.event->n_dynamic_fields) {
1744 va_start(args, n_vals);
1745
1746 for (i = 0; i < state.event->n_fields; i++) {
1747 u64 val = va_arg(args, u64);
1748
1749 if (state.event->fields[i]->is_string &&
1750 state.event->fields[i]->is_dynamic) {
1751 char *str_val = (char *)(long)val;
1752
1753 data_size += strlen(str_val) + 1;
1754 }
1755 }
1756
1757 va_end(args);
1758 }
1759
1760 ret = __synth_event_trace_start(file, &state, data_size);
1761 if (ret)
1762 return ret;
1763
1764 if (n_vals != state.event->n_fields) {
1765 ret = -EINVAL;
1766 goto out;
1767 }
1768
1769 data_size = 0;
1770
1771 va_start(args, n_vals);
1772 for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1773 u64 val;
1774
1775 val = va_arg(args, u64);
1776
1777 if (state.event->fields[i]->is_string) {
1778 char *str_val = (char *)(long)val;
1779
1780 len = trace_string(state.entry, state.event, str_val,
1781 state.event->fields[i]->is_dynamic,
1782 data_size, &n_u64);
1783 data_size += len; /* only dynamic string increments */
1784 } else {
1785 struct synth_field *field = state.event->fields[i];
1786
1787 switch (field->size) {
1788 case 1:
1789 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1790 break;
1791
1792 case 2:
1793 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1794 break;
1795
1796 case 4:
1797 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1798 break;
1799
1800 default:
1801 state.entry->fields[n_u64] = val;
1802 break;
1803 }
1804 n_u64++;
1805 }
1806 }
1807 va_end(args);
1808 out:
1809 __synth_event_trace_end(&state);
1810
1811 return ret;
1812 }
1813 EXPORT_SYMBOL_GPL(synth_event_trace);
1814
1815 /**
1816 * synth_event_trace_array - Trace a synthetic event from an array
1817 * @file: The trace_event_file representing the synthetic event
1818 * @vals: Array of values
1819 * @n_vals: The number of values in vals
1820 *
1821 * Trace a synthetic event using the values passed in as 'vals'.
1822 *
1823 * The 'vals' array is just an array of 'n_vals' u64. The number of
1824 * vals must match the number of field in the synthetic event, and
1825 * must be in the same order as the synthetic event fields.
1826 *
1827 * All vals should be cast to u64, and string vals are just pointers
1828 * to strings, cast to u64. Strings will be copied into space
1829 * reserved in the event for the string, using these pointers.
1830 *
1831 * Return: 0 on success, err otherwise.
1832 */
synth_event_trace_array(struct trace_event_file * file,u64 * vals,unsigned int n_vals)1833 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1834 unsigned int n_vals)
1835 {
1836 unsigned int i, n_u64, field_pos, len, data_size = 0;
1837 struct synth_event_trace_state state;
1838 char *str_val;
1839 int ret;
1840
1841 ret = __synth_event_trace_init(file, &state);
1842 if (ret) {
1843 if (ret == -ENOENT)
1844 ret = 0; /* just disabled, not really an error */
1845 return ret;
1846 }
1847
1848 if (state.event->n_dynamic_fields) {
1849 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1850 field_pos = state.event->dynamic_fields[i]->field_pos;
1851 str_val = (char *)(long)vals[field_pos];
1852 len = strlen(str_val) + 1;
1853 data_size += len;
1854 }
1855 }
1856
1857 ret = __synth_event_trace_start(file, &state, data_size);
1858 if (ret)
1859 return ret;
1860
1861 if (n_vals != state.event->n_fields) {
1862 ret = -EINVAL;
1863 goto out;
1864 }
1865
1866 data_size = 0;
1867
1868 for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1869 if (state.event->fields[i]->is_string) {
1870 char *str_val = (char *)(long)vals[i];
1871
1872 len = trace_string(state.entry, state.event, str_val,
1873 state.event->fields[i]->is_dynamic,
1874 data_size, &n_u64);
1875 data_size += len; /* only dynamic string increments */
1876 } else {
1877 struct synth_field *field = state.event->fields[i];
1878 u64 val = vals[i];
1879
1880 switch (field->size) {
1881 case 1:
1882 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1883 break;
1884
1885 case 2:
1886 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1887 break;
1888
1889 case 4:
1890 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1891 break;
1892
1893 default:
1894 state.entry->fields[n_u64] = val;
1895 break;
1896 }
1897 n_u64++;
1898 }
1899 }
1900 out:
1901 __synth_event_trace_end(&state);
1902
1903 return ret;
1904 }
1905 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1906
1907 /**
1908 * synth_event_trace_start - Start piecewise synthetic event trace
1909 * @file: The trace_event_file representing the synthetic event
1910 * @trace_state: A pointer to object tracking the piecewise trace state
1911 *
1912 * Start the trace of a synthetic event field-by-field rather than all
1913 * at once.
1914 *
1915 * This function 'opens' an event trace, which means space is reserved
1916 * for the event in the trace buffer, after which the event's
1917 * individual field values can be set through either
1918 * synth_event_add_next_val() or synth_event_add_val().
1919 *
1920 * A pointer to a trace_state object is passed in, which will keep
1921 * track of the current event trace state until the event trace is
1922 * closed (and the event finally traced) using
1923 * synth_event_trace_end().
1924 *
1925 * Note that synth_event_trace_end() must be called after all values
1926 * have been added for each event trace, regardless of whether adding
1927 * all field values succeeded or not.
1928 *
1929 * Note also that for a given event trace, all fields must be added
1930 * using either synth_event_add_next_val() or synth_event_add_val()
1931 * but not both together or interleaved.
1932 *
1933 * Return: 0 on success, err otherwise.
1934 */
synth_event_trace_start(struct trace_event_file * file,struct synth_event_trace_state * trace_state)1935 int synth_event_trace_start(struct trace_event_file *file,
1936 struct synth_event_trace_state *trace_state)
1937 {
1938 int ret;
1939
1940 if (!trace_state)
1941 return -EINVAL;
1942
1943 ret = __synth_event_trace_init(file, trace_state);
1944 if (ret) {
1945 if (ret == -ENOENT)
1946 ret = 0; /* just disabled, not really an error */
1947 return ret;
1948 }
1949
1950 if (trace_state->event->n_dynamic_fields)
1951 return -ENOTSUPP;
1952
1953 ret = __synth_event_trace_start(file, trace_state, 0);
1954
1955 return ret;
1956 }
1957 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1958
__synth_event_add_val(const char * field_name,u64 val,struct synth_event_trace_state * trace_state)1959 static int __synth_event_add_val(const char *field_name, u64 val,
1960 struct synth_event_trace_state *trace_state)
1961 {
1962 struct synth_field *field = NULL;
1963 struct synth_trace_event *entry;
1964 struct synth_event *event;
1965 int i, ret = 0;
1966
1967 if (!trace_state) {
1968 ret = -EINVAL;
1969 goto out;
1970 }
1971
1972 /* can't mix add_next_synth_val() with add_synth_val() */
1973 if (field_name) {
1974 if (trace_state->add_next) {
1975 ret = -EINVAL;
1976 goto out;
1977 }
1978 trace_state->add_name = true;
1979 } else {
1980 if (trace_state->add_name) {
1981 ret = -EINVAL;
1982 goto out;
1983 }
1984 trace_state->add_next = true;
1985 }
1986
1987 if (trace_state->disabled)
1988 goto out;
1989
1990 event = trace_state->event;
1991 if (trace_state->add_name) {
1992 for (i = 0; i < event->n_fields; i++) {
1993 field = event->fields[i];
1994 if (strcmp(field->name, field_name) == 0)
1995 break;
1996 }
1997 if (!field) {
1998 ret = -EINVAL;
1999 goto out;
2000 }
2001 } else {
2002 if (trace_state->cur_field >= event->n_fields) {
2003 ret = -EINVAL;
2004 goto out;
2005 }
2006 field = event->fields[trace_state->cur_field++];
2007 }
2008
2009 entry = trace_state->entry;
2010 if (field->is_string) {
2011 char *str_val = (char *)(long)val;
2012 char *str_field;
2013
2014 if (field->is_dynamic) { /* add_val can't do dynamic strings */
2015 ret = -EINVAL;
2016 goto out;
2017 }
2018
2019 if (!str_val) {
2020 ret = -EINVAL;
2021 goto out;
2022 }
2023
2024 str_field = (char *)&entry->fields[field->offset];
2025 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2026 } else {
2027 switch (field->size) {
2028 case 1:
2029 *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
2030 break;
2031
2032 case 2:
2033 *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
2034 break;
2035
2036 case 4:
2037 *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
2038 break;
2039
2040 default:
2041 trace_state->entry->fields[field->offset] = val;
2042 break;
2043 }
2044 }
2045 out:
2046 return ret;
2047 }
2048
2049 /**
2050 * synth_event_add_next_val - Add the next field's value to an open synth trace
2051 * @val: The value to set the next field to
2052 * @trace_state: A pointer to object tracking the piecewise trace state
2053 *
2054 * Set the value of the next field in an event that's been opened by
2055 * synth_event_trace_start().
2056 *
2057 * The val param should be the value cast to u64. If the value points
2058 * to a string, the val param should be a char * cast to u64.
2059 *
2060 * This function assumes all the fields in an event are to be set one
2061 * after another - successive calls to this function are made, one for
2062 * each field, in the order of the fields in the event, until all
2063 * fields have been set. If you'd rather set each field individually
2064 * without regard to ordering, synth_event_add_val() can be used
2065 * instead.
2066 *
2067 * Note however that synth_event_add_next_val() and
2068 * synth_event_add_val() can't be intermixed for a given event trace -
2069 * one or the other but not both can be used at the same time.
2070 *
2071 * Note also that synth_event_trace_end() must be called after all
2072 * values have been added for each event trace, regardless of whether
2073 * adding all field values succeeded or not.
2074 *
2075 * Return: 0 on success, err otherwise.
2076 */
synth_event_add_next_val(u64 val,struct synth_event_trace_state * trace_state)2077 int synth_event_add_next_val(u64 val,
2078 struct synth_event_trace_state *trace_state)
2079 {
2080 return __synth_event_add_val(NULL, val, trace_state);
2081 }
2082 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2083
2084 /**
2085 * synth_event_add_val - Add a named field's value to an open synth trace
2086 * @field_name: The name of the synthetic event field value to set
2087 * @val: The value to set the named field to
2088 * @trace_state: A pointer to object tracking the piecewise trace state
2089 *
2090 * Set the value of the named field in an event that's been opened by
2091 * synth_event_trace_start().
2092 *
2093 * The val param should be the value cast to u64. If the value points
2094 * to a string, the val param should be a char * cast to u64.
2095 *
2096 * This function looks up the field name, and if found, sets the field
2097 * to the specified value. This lookup makes this function more
2098 * expensive than synth_event_add_next_val(), so use that or the
2099 * none-piecewise synth_event_trace() instead if efficiency is more
2100 * important.
2101 *
2102 * Note however that synth_event_add_next_val() and
2103 * synth_event_add_val() can't be intermixed for a given event trace -
2104 * one or the other but not both can be used at the same time.
2105 *
2106 * Note also that synth_event_trace_end() must be called after all
2107 * values have been added for each event trace, regardless of whether
2108 * adding all field values succeeded or not.
2109 *
2110 * Return: 0 on success, err otherwise.
2111 */
synth_event_add_val(const char * field_name,u64 val,struct synth_event_trace_state * trace_state)2112 int synth_event_add_val(const char *field_name, u64 val,
2113 struct synth_event_trace_state *trace_state)
2114 {
2115 return __synth_event_add_val(field_name, val, trace_state);
2116 }
2117 EXPORT_SYMBOL_GPL(synth_event_add_val);
2118
2119 /**
2120 * synth_event_trace_end - End piecewise synthetic event trace
2121 * @trace_state: A pointer to object tracking the piecewise trace state
2122 *
2123 * End the trace of a synthetic event opened by
2124 * synth_event_trace__start().
2125 *
2126 * This function 'closes' an event trace, which basically means that
2127 * it commits the reserved event and cleans up other loose ends.
2128 *
2129 * A pointer to a trace_state object is passed in, which will keep
2130 * track of the current event trace state opened with
2131 * synth_event_trace_start().
2132 *
2133 * Note that this function must be called after all values have been
2134 * added for each event trace, regardless of whether adding all field
2135 * values succeeded or not.
2136 *
2137 * Return: 0 on success, err otherwise.
2138 */
synth_event_trace_end(struct synth_event_trace_state * trace_state)2139 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2140 {
2141 if (!trace_state)
2142 return -EINVAL;
2143
2144 __synth_event_trace_end(trace_state);
2145
2146 return 0;
2147 }
2148 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2149
create_synth_event(const char * raw_command)2150 static int create_synth_event(const char *raw_command)
2151 {
2152 char *fields, *p;
2153 const char *name;
2154 int len, ret = 0;
2155
2156 raw_command = skip_spaces(raw_command);
2157 if (raw_command[0] == '\0')
2158 return ret;
2159
2160 last_cmd_set(raw_command);
2161
2162 name = raw_command;
2163
2164 /* Don't try to process if not our system */
2165 if (name[0] != 's' || name[1] != ':')
2166 return -ECANCELED;
2167 name += 2;
2168
2169 p = strpbrk(raw_command, " \t");
2170 if (!p) {
2171 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2172 return -EINVAL;
2173 }
2174
2175 fields = skip_spaces(p);
2176
2177 /* This interface accepts group name prefix */
2178 if (strchr(name, '/')) {
2179 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2180 if (len == 0) {
2181 synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2182 return -EINVAL;
2183 }
2184 name += len;
2185 }
2186
2187 len = name - raw_command;
2188
2189 ret = check_command(raw_command + len);
2190 if (ret) {
2191 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2192 return ret;
2193 }
2194
2195 name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2196 if (!name)
2197 return -ENOMEM;
2198
2199 ret = __create_synth_event(name, fields);
2200
2201 kfree(name);
2202
2203 return ret;
2204 }
2205
synth_event_release(struct dyn_event * ev)2206 static int synth_event_release(struct dyn_event *ev)
2207 {
2208 struct synth_event *event = to_synth_event(ev);
2209 int ret;
2210
2211 if (event->ref)
2212 return -EBUSY;
2213
2214 if (trace_event_dyn_busy(&event->call))
2215 return -EBUSY;
2216
2217 ret = unregister_synth_event(event);
2218 if (ret)
2219 return ret;
2220
2221 dyn_event_remove(ev);
2222 free_synth_event(event);
2223 return 0;
2224 }
2225
__synth_event_show(struct seq_file * m,struct synth_event * event)2226 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2227 {
2228 struct synth_field *field;
2229 unsigned int i;
2230 char *type, *t;
2231
2232 seq_printf(m, "%s\t", event->name);
2233
2234 for (i = 0; i < event->n_fields; i++) {
2235 field = event->fields[i];
2236
2237 type = field->type;
2238 t = strstr(type, "__data_loc");
2239 if (t) { /* __data_loc belongs in format but not event desc */
2240 t += sizeof("__data_loc");
2241 type = t;
2242 }
2243
2244 /* parameter values */
2245 seq_printf(m, "%s %s%s", type, field->name,
2246 i == event->n_fields - 1 ? "" : "; ");
2247 }
2248
2249 seq_putc(m, '\n');
2250
2251 return 0;
2252 }
2253
synth_event_show(struct seq_file * m,struct dyn_event * ev)2254 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2255 {
2256 struct synth_event *event = to_synth_event(ev);
2257
2258 seq_printf(m, "s:%s/", event->class.system);
2259
2260 return __synth_event_show(m, event);
2261 }
2262
synth_events_seq_show(struct seq_file * m,void * v)2263 static int synth_events_seq_show(struct seq_file *m, void *v)
2264 {
2265 struct dyn_event *ev = v;
2266
2267 if (!is_synth_event(ev))
2268 return 0;
2269
2270 return __synth_event_show(m, to_synth_event(ev));
2271 }
2272
2273 static const struct seq_operations synth_events_seq_op = {
2274 .start = dyn_event_seq_start,
2275 .next = dyn_event_seq_next,
2276 .stop = dyn_event_seq_stop,
2277 .show = synth_events_seq_show,
2278 };
2279
synth_events_open(struct inode * inode,struct file * file)2280 static int synth_events_open(struct inode *inode, struct file *file)
2281 {
2282 int ret;
2283
2284 ret = security_locked_down(LOCKDOWN_TRACEFS);
2285 if (ret)
2286 return ret;
2287
2288 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2289 ret = dyn_events_release_all(&synth_event_ops);
2290 if (ret < 0)
2291 return ret;
2292 }
2293
2294 return seq_open(file, &synth_events_seq_op);
2295 }
2296
synth_events_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)2297 static ssize_t synth_events_write(struct file *file,
2298 const char __user *buffer,
2299 size_t count, loff_t *ppos)
2300 {
2301 return trace_parse_run_command(file, buffer, count, ppos,
2302 create_or_delete_synth_event);
2303 }
2304
2305 static const struct file_operations synth_events_fops = {
2306 .open = synth_events_open,
2307 .write = synth_events_write,
2308 .read = seq_read,
2309 .llseek = seq_lseek,
2310 .release = seq_release,
2311 };
2312
2313 /*
2314 * Register dynevent at core_initcall. This allows kernel to setup kprobe
2315 * events in postcore_initcall without tracefs.
2316 */
trace_events_synth_init_early(void)2317 static __init int trace_events_synth_init_early(void)
2318 {
2319 int err = 0;
2320
2321 err = dyn_event_register(&synth_event_ops);
2322 if (err)
2323 pr_warn("Could not register synth_event_ops\n");
2324
2325 return err;
2326 }
2327 core_initcall(trace_events_synth_init_early);
2328
trace_events_synth_init(void)2329 static __init int trace_events_synth_init(void)
2330 {
2331 struct dentry *entry = NULL;
2332 int err = 0;
2333 err = tracing_init_dentry();
2334 if (err)
2335 goto err;
2336
2337 entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2338 NULL, NULL, &synth_events_fops);
2339 if (!entry) {
2340 err = -ENODEV;
2341 goto err;
2342 }
2343
2344 return err;
2345 err:
2346 pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2347
2348 return err;
2349 }
2350
2351 fs_initcall(trace_events_synth_init);
2352