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 char last_cmd[MAX_FILTER_STR_VAL];
48
errpos(const char * str)49 static int errpos(const char *str)
50 {
51 return err_pos(last_cmd, str);
52 }
53
last_cmd_set(const char * str)54 static void last_cmd_set(const char *str)
55 {
56 if (!str)
57 return;
58
59 strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
60 }
61
synth_err(u8 err_type,u8 err_pos)62 static void synth_err(u8 err_type, u8 err_pos)
63 {
64 tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
65 err_type, err_pos);
66 }
67
68 static int create_synth_event(const char *raw_command);
69 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
70 static int synth_event_release(struct dyn_event *ev);
71 static bool synth_event_is_busy(struct dyn_event *ev);
72 static bool synth_event_match(const char *system, const char *event,
73 int argc, const char **argv, struct dyn_event *ev);
74
75 static struct dyn_event_operations synth_event_ops = {
76 .create = create_synth_event,
77 .show = synth_event_show,
78 .is_busy = synth_event_is_busy,
79 .free = synth_event_release,
80 .match = synth_event_match,
81 };
82
is_synth_event(struct dyn_event * ev)83 static bool is_synth_event(struct dyn_event *ev)
84 {
85 return ev->ops == &synth_event_ops;
86 }
87
to_synth_event(struct dyn_event * ev)88 static struct synth_event *to_synth_event(struct dyn_event *ev)
89 {
90 return container_of(ev, struct synth_event, devent);
91 }
92
synth_event_is_busy(struct dyn_event * ev)93 static bool synth_event_is_busy(struct dyn_event *ev)
94 {
95 struct synth_event *event = to_synth_event(ev);
96
97 return event->ref != 0;
98 }
99
synth_event_match(const char * system,const char * event,int argc,const char ** argv,struct dyn_event * ev)100 static bool synth_event_match(const char *system, const char *event,
101 int argc, const char **argv, struct dyn_event *ev)
102 {
103 struct synth_event *sev = to_synth_event(ev);
104
105 return strcmp(sev->name, event) == 0 &&
106 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
107 }
108
109 struct synth_trace_event {
110 struct trace_entry ent;
111 u64 fields[];
112 };
113
synth_event_define_fields(struct trace_event_call * call)114 static int synth_event_define_fields(struct trace_event_call *call)
115 {
116 struct synth_trace_event trace;
117 int offset = offsetof(typeof(trace), fields);
118 struct synth_event *event = call->data;
119 unsigned int i, size, n_u64;
120 char *name, *type;
121 bool is_signed;
122 int ret = 0;
123
124 for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
125 size = event->fields[i]->size;
126 is_signed = event->fields[i]->is_signed;
127 type = event->fields[i]->type;
128 name = event->fields[i]->name;
129 ret = trace_define_field(call, type, name, offset, size,
130 is_signed, FILTER_OTHER);
131 if (ret)
132 break;
133
134 event->fields[i]->offset = n_u64;
135
136 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
137 offset += STR_VAR_LEN_MAX;
138 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
139 } else {
140 offset += sizeof(u64);
141 n_u64++;
142 }
143 }
144
145 event->n_u64 = n_u64;
146
147 return ret;
148 }
149
synth_field_signed(char * type)150 static bool synth_field_signed(char *type)
151 {
152 if (str_has_prefix(type, "u"))
153 return false;
154 if (strcmp(type, "gfp_t") == 0)
155 return false;
156
157 return true;
158 }
159
synth_field_is_string(char * type)160 static int synth_field_is_string(char *type)
161 {
162 if (strstr(type, "char[") != NULL)
163 return true;
164
165 return false;
166 }
167
synth_field_is_stack(char * type)168 static int synth_field_is_stack(char *type)
169 {
170 if (strstr(type, "long[") != NULL)
171 return true;
172
173 return false;
174 }
175
synth_field_string_size(char * type)176 static int synth_field_string_size(char *type)
177 {
178 char buf[4], *end, *start;
179 unsigned int len;
180 int size, err;
181
182 start = strstr(type, "char[");
183 if (start == NULL)
184 return -EINVAL;
185 start += sizeof("char[") - 1;
186
187 end = strchr(type, ']');
188 if (!end || end < start || type + strlen(type) > end + 1)
189 return -EINVAL;
190
191 len = end - start;
192 if (len > 3)
193 return -EINVAL;
194
195 if (len == 0)
196 return 0; /* variable-length string */
197
198 strncpy(buf, start, len);
199 buf[len] = '\0';
200
201 err = kstrtouint(buf, 0, &size);
202 if (err)
203 return err;
204
205 if (size > STR_VAR_LEN_MAX)
206 return -EINVAL;
207
208 return size;
209 }
210
synth_field_size(char * type)211 static int synth_field_size(char *type)
212 {
213 int size = 0;
214
215 if (strcmp(type, "s64") == 0)
216 size = sizeof(s64);
217 else if (strcmp(type, "u64") == 0)
218 size = sizeof(u64);
219 else if (strcmp(type, "s32") == 0)
220 size = sizeof(s32);
221 else if (strcmp(type, "u32") == 0)
222 size = sizeof(u32);
223 else if (strcmp(type, "s16") == 0)
224 size = sizeof(s16);
225 else if (strcmp(type, "u16") == 0)
226 size = sizeof(u16);
227 else if (strcmp(type, "s8") == 0)
228 size = sizeof(s8);
229 else if (strcmp(type, "u8") == 0)
230 size = sizeof(u8);
231 else if (strcmp(type, "char") == 0)
232 size = sizeof(char);
233 else if (strcmp(type, "unsigned char") == 0)
234 size = sizeof(unsigned char);
235 else if (strcmp(type, "int") == 0)
236 size = sizeof(int);
237 else if (strcmp(type, "unsigned int") == 0)
238 size = sizeof(unsigned int);
239 else if (strcmp(type, "long") == 0)
240 size = sizeof(long);
241 else if (strcmp(type, "unsigned long") == 0)
242 size = sizeof(unsigned long);
243 else if (strcmp(type, "bool") == 0)
244 size = sizeof(bool);
245 else if (strcmp(type, "pid_t") == 0)
246 size = sizeof(pid_t);
247 else if (strcmp(type, "gfp_t") == 0)
248 size = sizeof(gfp_t);
249 else if (synth_field_is_string(type))
250 size = synth_field_string_size(type);
251 else if (synth_field_is_stack(type))
252 size = 0;
253
254 return size;
255 }
256
synth_field_fmt(char * type)257 static const char *synth_field_fmt(char *type)
258 {
259 const char *fmt = "%llu";
260
261 if (strcmp(type, "s64") == 0)
262 fmt = "%lld";
263 else if (strcmp(type, "u64") == 0)
264 fmt = "%llu";
265 else if (strcmp(type, "s32") == 0)
266 fmt = "%d";
267 else if (strcmp(type, "u32") == 0)
268 fmt = "%u";
269 else if (strcmp(type, "s16") == 0)
270 fmt = "%d";
271 else if (strcmp(type, "u16") == 0)
272 fmt = "%u";
273 else if (strcmp(type, "s8") == 0)
274 fmt = "%d";
275 else if (strcmp(type, "u8") == 0)
276 fmt = "%u";
277 else if (strcmp(type, "char") == 0)
278 fmt = "%d";
279 else if (strcmp(type, "unsigned char") == 0)
280 fmt = "%u";
281 else if (strcmp(type, "int") == 0)
282 fmt = "%d";
283 else if (strcmp(type, "unsigned int") == 0)
284 fmt = "%u";
285 else if (strcmp(type, "long") == 0)
286 fmt = "%ld";
287 else if (strcmp(type, "unsigned long") == 0)
288 fmt = "%lu";
289 else if (strcmp(type, "bool") == 0)
290 fmt = "%d";
291 else if (strcmp(type, "pid_t") == 0)
292 fmt = "%d";
293 else if (strcmp(type, "gfp_t") == 0)
294 fmt = "%x";
295 else if (synth_field_is_string(type))
296 fmt = "%.*s";
297 else if (synth_field_is_stack(type))
298 fmt = "%s";
299
300 return fmt;
301 }
302
print_synth_event_num_val(struct trace_seq * s,char * print_fmt,char * name,int size,u64 val,char * space)303 static void print_synth_event_num_val(struct trace_seq *s,
304 char *print_fmt, char *name,
305 int size, u64 val, char *space)
306 {
307 switch (size) {
308 case 1:
309 trace_seq_printf(s, print_fmt, name, (u8)val, space);
310 break;
311
312 case 2:
313 trace_seq_printf(s, print_fmt, name, (u16)val, space);
314 break;
315
316 case 4:
317 trace_seq_printf(s, print_fmt, name, (u32)val, space);
318 break;
319
320 default:
321 trace_seq_printf(s, print_fmt, name, val, space);
322 break;
323 }
324 }
325
print_synth_event(struct trace_iterator * iter,int flags,struct trace_event * event)326 static enum print_line_t print_synth_event(struct trace_iterator *iter,
327 int flags,
328 struct trace_event *event)
329 {
330 struct trace_array *tr = iter->tr;
331 struct trace_seq *s = &iter->seq;
332 struct synth_trace_event *entry;
333 struct synth_event *se;
334 unsigned int i, n_u64;
335 char print_fmt[32];
336 const char *fmt;
337
338 entry = (struct synth_trace_event *)iter->ent;
339 se = container_of(event, struct synth_event, call.event);
340
341 trace_seq_printf(s, "%s: ", se->name);
342
343 for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
344 if (trace_seq_has_overflowed(s))
345 goto end;
346
347 fmt = synth_field_fmt(se->fields[i]->type);
348
349 /* parameter types */
350 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
351 trace_seq_printf(s, "%s ", fmt);
352
353 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
354
355 /* parameter values */
356 if (se->fields[i]->is_string) {
357 if (se->fields[i]->is_dynamic) {
358 u32 offset, data_offset;
359 char *str_field;
360
361 offset = (u32)entry->fields[n_u64];
362 data_offset = offset & 0xffff;
363
364 str_field = (char *)entry + data_offset;
365
366 trace_seq_printf(s, print_fmt, se->fields[i]->name,
367 STR_VAR_LEN_MAX,
368 str_field,
369 i == se->n_fields - 1 ? "" : " ");
370 n_u64++;
371 } else {
372 trace_seq_printf(s, print_fmt, se->fields[i]->name,
373 STR_VAR_LEN_MAX,
374 (char *)&entry->fields[n_u64],
375 i == se->n_fields - 1 ? "" : " ");
376 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
377 }
378 } else if (se->fields[i]->is_stack) {
379 u32 offset, data_offset, len;
380 unsigned long *p, *end;
381
382 offset = (u32)entry->fields[n_u64];
383 data_offset = offset & 0xffff;
384 len = offset >> 16;
385
386 p = (void *)entry + data_offset;
387 end = (void *)p + len - (sizeof(long) - 1);
388
389 trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
390
391 for (; *p && p < end; p++)
392 trace_seq_printf(s, "=> %pS\n", (void *)*p);
393 n_u64++;
394
395 } else {
396 struct trace_print_flags __flags[] = {
397 __def_gfpflag_names, {-1, NULL} };
398 char *space = (i == se->n_fields - 1 ? "" : " ");
399
400 print_synth_event_num_val(s, print_fmt,
401 se->fields[i]->name,
402 se->fields[i]->size,
403 entry->fields[n_u64],
404 space);
405
406 if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
407 trace_seq_puts(s, " (");
408 trace_print_flags_seq(s, "|",
409 entry->fields[n_u64],
410 __flags);
411 trace_seq_putc(s, ')');
412 }
413 n_u64++;
414 }
415 }
416 end:
417 trace_seq_putc(s, '\n');
418
419 return trace_handle_return(s);
420 }
421
422 static struct trace_event_functions synth_event_funcs = {
423 .trace = print_synth_event
424 };
425
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)426 static unsigned int trace_string(struct synth_trace_event *entry,
427 struct synth_event *event,
428 char *str_val,
429 bool is_dynamic,
430 unsigned int data_size,
431 unsigned int *n_u64)
432 {
433 unsigned int len = 0;
434 char *str_field;
435 int ret;
436
437 if (is_dynamic) {
438 u32 data_offset;
439
440 data_offset = offsetof(typeof(*entry), fields);
441 data_offset += event->n_u64 * sizeof(u64);
442 data_offset += data_size;
443
444 len = kern_fetch_store_strlen((unsigned long)str_val);
445
446 data_offset |= len << 16;
447 *(u32 *)&entry->fields[*n_u64] = data_offset;
448
449 ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
450
451 (*n_u64)++;
452 } else {
453 str_field = (char *)&entry->fields[*n_u64];
454
455 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
456 if ((unsigned long)str_val < TASK_SIZE)
457 ret = strncpy_from_user_nofault(str_field, (const void __user *)str_val, STR_VAR_LEN_MAX);
458 else
459 #endif
460 ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
461
462 if (ret < 0)
463 strcpy(str_field, FAULT_STRING);
464
465 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
466 }
467
468 return len;
469 }
470
trace_stack(struct synth_trace_event * entry,struct synth_event * event,long * stack,unsigned int data_size,unsigned int * n_u64)471 static unsigned int trace_stack(struct synth_trace_event *entry,
472 struct synth_event *event,
473 long *stack,
474 unsigned int data_size,
475 unsigned int *n_u64)
476 {
477 unsigned int len;
478 u32 data_offset;
479 void *data_loc;
480
481 data_offset = struct_size(entry, fields, event->n_u64);
482 data_offset += data_size;
483
484 for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
485 if (!stack[len])
486 break;
487 }
488
489 /* Include the zero'd element if it fits */
490 if (len < HIST_STACKTRACE_DEPTH)
491 len++;
492
493 len *= sizeof(long);
494
495 /* Find the dynamic section to copy the stack into. */
496 data_loc = (void *)entry + data_offset;
497 memcpy(data_loc, stack, len);
498
499 /* Fill in the field that holds the offset/len combo */
500 data_offset |= len << 16;
501 *(u32 *)&entry->fields[*n_u64] = data_offset;
502
503 (*n_u64)++;
504
505 return len;
506 }
507
trace_event_raw_event_synth(void * __data,u64 * var_ref_vals,unsigned int * var_ref_idx)508 static notrace void trace_event_raw_event_synth(void *__data,
509 u64 *var_ref_vals,
510 unsigned int *var_ref_idx)
511 {
512 unsigned int i, n_u64, val_idx, len, data_size = 0;
513 struct trace_event_file *trace_file = __data;
514 struct synth_trace_event *entry;
515 struct trace_event_buffer fbuffer;
516 struct trace_buffer *buffer;
517 struct synth_event *event;
518 int fields_size = 0;
519
520 event = trace_file->event_call->data;
521
522 if (trace_trigger_soft_disabled(trace_file))
523 return;
524
525 fields_size = event->n_u64 * sizeof(u64);
526
527 for (i = 0; i < event->n_dynamic_fields; i++) {
528 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
529 char *str_val;
530
531 val_idx = var_ref_idx[field_pos];
532 str_val = (char *)(long)var_ref_vals[val_idx];
533
534 len = kern_fetch_store_strlen((unsigned long)str_val);
535
536 fields_size += len;
537 }
538
539 /*
540 * Avoid ring buffer recursion detection, as this event
541 * is being performed within another event.
542 */
543 buffer = trace_file->tr->array_buffer.buffer;
544 ring_buffer_nest_start(buffer);
545
546 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
547 sizeof(*entry) + fields_size);
548 if (!entry)
549 goto out;
550
551 for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
552 val_idx = var_ref_idx[i];
553 if (event->fields[i]->is_string) {
554 char *str_val = (char *)(long)var_ref_vals[val_idx];
555
556 len = trace_string(entry, event, str_val,
557 event->fields[i]->is_dynamic,
558 data_size, &n_u64);
559 data_size += len; /* only dynamic string increments */
560 } else if (event->fields[i]->is_stack) {
561 long *stack = (long *)(long)var_ref_vals[val_idx];
562
563 len = trace_stack(entry, event, stack,
564 data_size, &n_u64);
565 data_size += len;
566 } else {
567 struct synth_field *field = event->fields[i];
568 u64 val = var_ref_vals[val_idx];
569
570 switch (field->size) {
571 case 1:
572 *(u8 *)&entry->fields[n_u64] = (u8)val;
573 break;
574
575 case 2:
576 *(u16 *)&entry->fields[n_u64] = (u16)val;
577 break;
578
579 case 4:
580 *(u32 *)&entry->fields[n_u64] = (u32)val;
581 break;
582
583 default:
584 entry->fields[n_u64] = val;
585 break;
586 }
587 n_u64++;
588 }
589 }
590
591 trace_event_buffer_commit(&fbuffer);
592 out:
593 ring_buffer_nest_end(buffer);
594 }
595
free_synth_event_print_fmt(struct trace_event_call * call)596 static void free_synth_event_print_fmt(struct trace_event_call *call)
597 {
598 if (call) {
599 kfree(call->print_fmt);
600 call->print_fmt = NULL;
601 }
602 }
603
__set_synth_event_print_fmt(struct synth_event * event,char * buf,int len)604 static int __set_synth_event_print_fmt(struct synth_event *event,
605 char *buf, int len)
606 {
607 const char *fmt;
608 int pos = 0;
609 int i;
610
611 /* When len=0, we just calculate the needed length */
612 #define LEN_OR_ZERO (len ? len - pos : 0)
613
614 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
615 for (i = 0; i < event->n_fields; i++) {
616 fmt = synth_field_fmt(event->fields[i]->type);
617 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
618 event->fields[i]->name, fmt,
619 i == event->n_fields - 1 ? "" : ", ");
620 }
621 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
622
623 for (i = 0; i < event->n_fields; i++) {
624 if (event->fields[i]->is_string &&
625 event->fields[i]->is_dynamic)
626 pos += snprintf(buf + pos, LEN_OR_ZERO,
627 ", __get_str(%s)", event->fields[i]->name);
628 else if (event->fields[i]->is_stack)
629 pos += snprintf(buf + pos, LEN_OR_ZERO,
630 ", __get_stacktrace(%s)", event->fields[i]->name);
631 else
632 pos += snprintf(buf + pos, LEN_OR_ZERO,
633 ", REC->%s", event->fields[i]->name);
634 }
635
636 #undef LEN_OR_ZERO
637
638 /* return the length of print_fmt */
639 return pos;
640 }
641
set_synth_event_print_fmt(struct trace_event_call * call)642 static int set_synth_event_print_fmt(struct trace_event_call *call)
643 {
644 struct synth_event *event = call->data;
645 char *print_fmt;
646 int len;
647
648 /* First: called with 0 length to calculate the needed length */
649 len = __set_synth_event_print_fmt(event, NULL, 0);
650
651 print_fmt = kmalloc(len + 1, GFP_KERNEL);
652 if (!print_fmt)
653 return -ENOMEM;
654
655 /* Second: actually write the @print_fmt */
656 __set_synth_event_print_fmt(event, print_fmt, len + 1);
657 call->print_fmt = print_fmt;
658
659 return 0;
660 }
661
free_synth_field(struct synth_field * field)662 static void free_synth_field(struct synth_field *field)
663 {
664 kfree(field->type);
665 kfree(field->name);
666 kfree(field);
667 }
668
check_field_version(const char * prefix,const char * field_type,const char * field_name)669 static int check_field_version(const char *prefix, const char *field_type,
670 const char *field_name)
671 {
672 /*
673 * For backward compatibility, the old synthetic event command
674 * format did not require semicolons, and in order to not
675 * break user space, that old format must still work. If a new
676 * feature is added, then the format that uses the new feature
677 * will be required to have semicolons, as nothing that uses
678 * the old format would be using the new, yet to be created,
679 * feature. When a new feature is added, this will detect it,
680 * and return a number greater than 1, and require the format
681 * to use semicolons.
682 */
683 return 1;
684 }
685
parse_synth_field(int argc,char ** argv,int * consumed,int * field_version)686 static struct synth_field *parse_synth_field(int argc, char **argv,
687 int *consumed, int *field_version)
688 {
689 const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
690 struct synth_field *field;
691 int len, ret = -ENOMEM;
692 struct seq_buf s;
693 ssize_t size;
694
695 if (!strcmp(field_type, "unsigned")) {
696 if (argc < 3) {
697 synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
698 return ERR_PTR(-EINVAL);
699 }
700 prefix = "unsigned ";
701 field_type = argv[1];
702 field_name = argv[2];
703 *consumed += 3;
704 } else {
705 field_name = argv[1];
706 *consumed += 2;
707 }
708
709 if (!field_name) {
710 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
711 return ERR_PTR(-EINVAL);
712 }
713
714 *field_version = check_field_version(prefix, field_type, field_name);
715
716 field = kzalloc(sizeof(*field), GFP_KERNEL);
717 if (!field)
718 return ERR_PTR(-ENOMEM);
719
720 len = strlen(field_name);
721 array = strchr(field_name, '[');
722 if (array)
723 len -= strlen(array);
724
725 field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
726 if (!field->name)
727 goto free;
728
729 if (!is_good_name(field->name)) {
730 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
731 ret = -EINVAL;
732 goto free;
733 }
734
735 len = strlen(field_type) + 1;
736
737 if (array)
738 len += strlen(array);
739
740 if (prefix)
741 len += strlen(prefix);
742
743 field->type = kzalloc(len, GFP_KERNEL);
744 if (!field->type)
745 goto free;
746
747 seq_buf_init(&s, field->type, len);
748 if (prefix)
749 seq_buf_puts(&s, prefix);
750 seq_buf_puts(&s, field_type);
751 if (array)
752 seq_buf_puts(&s, array);
753 if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
754 goto free;
755
756 s.buffer[s.len] = '\0';
757
758 size = synth_field_size(field->type);
759 if (size < 0) {
760 if (array)
761 synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
762 else
763 synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
764 ret = -EINVAL;
765 goto free;
766 } else if (size == 0) {
767 if (synth_field_is_string(field->type) ||
768 synth_field_is_stack(field->type)) {
769 char *type;
770
771 len = sizeof("__data_loc ") + strlen(field->type) + 1;
772 type = kzalloc(len, GFP_KERNEL);
773 if (!type)
774 goto free;
775
776 seq_buf_init(&s, type, len);
777 seq_buf_puts(&s, "__data_loc ");
778 seq_buf_puts(&s, field->type);
779
780 if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
781 goto free;
782 s.buffer[s.len] = '\0';
783
784 kfree(field->type);
785 field->type = type;
786
787 field->is_dynamic = true;
788 size = sizeof(u64);
789 } else {
790 synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
791 ret = -EINVAL;
792 goto free;
793 }
794 }
795 field->size = size;
796
797 if (synth_field_is_string(field->type))
798 field->is_string = true;
799 else if (synth_field_is_stack(field->type))
800 field->is_stack = true;
801
802 field->is_signed = synth_field_signed(field->type);
803 out:
804 return field;
805 free:
806 free_synth_field(field);
807 field = ERR_PTR(ret);
808 goto out;
809 }
810
free_synth_tracepoint(struct tracepoint * tp)811 static void free_synth_tracepoint(struct tracepoint *tp)
812 {
813 if (!tp)
814 return;
815
816 kfree(tp->name);
817 kfree(tp);
818 }
819
alloc_synth_tracepoint(char * name)820 static struct tracepoint *alloc_synth_tracepoint(char *name)
821 {
822 struct tracepoint *tp;
823
824 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
825 if (!tp)
826 return ERR_PTR(-ENOMEM);
827
828 tp->name = kstrdup(name, GFP_KERNEL);
829 if (!tp->name) {
830 kfree(tp);
831 return ERR_PTR(-ENOMEM);
832 }
833
834 return tp;
835 }
836
find_synth_event(const char * name)837 struct synth_event *find_synth_event(const char *name)
838 {
839 struct dyn_event *pos;
840 struct synth_event *event;
841
842 for_each_dyn_event(pos) {
843 if (!is_synth_event(pos))
844 continue;
845 event = to_synth_event(pos);
846 if (strcmp(event->name, name) == 0)
847 return event;
848 }
849
850 return NULL;
851 }
852
853 static struct trace_event_fields synth_event_fields_array[] = {
854 { .type = TRACE_FUNCTION_TYPE,
855 .define_fields = synth_event_define_fields },
856 {}
857 };
858
register_synth_event(struct synth_event * event)859 static int register_synth_event(struct synth_event *event)
860 {
861 struct trace_event_call *call = &event->call;
862 int ret = 0;
863
864 event->call.class = &event->class;
865 event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
866 if (!event->class.system) {
867 ret = -ENOMEM;
868 goto out;
869 }
870
871 event->tp = alloc_synth_tracepoint(event->name);
872 if (IS_ERR(event->tp)) {
873 ret = PTR_ERR(event->tp);
874 event->tp = NULL;
875 goto out;
876 }
877
878 INIT_LIST_HEAD(&call->class->fields);
879 call->event.funcs = &synth_event_funcs;
880 call->class->fields_array = synth_event_fields_array;
881
882 ret = register_trace_event(&call->event);
883 if (!ret) {
884 ret = -ENODEV;
885 goto out;
886 }
887 call->flags = TRACE_EVENT_FL_TRACEPOINT;
888 call->class->reg = trace_event_reg;
889 call->class->probe = trace_event_raw_event_synth;
890 call->data = event;
891 call->tp = event->tp;
892
893 ret = trace_add_event_call(call);
894 if (ret) {
895 pr_warn("Failed to register synthetic event: %s\n",
896 trace_event_name(call));
897 goto err;
898 }
899
900 ret = set_synth_event_print_fmt(call);
901 /* unregister_trace_event() will be called inside */
902 if (ret < 0)
903 trace_remove_event_call(call);
904 out:
905 return ret;
906 err:
907 unregister_trace_event(&call->event);
908 goto out;
909 }
910
unregister_synth_event(struct synth_event * event)911 static int unregister_synth_event(struct synth_event *event)
912 {
913 struct trace_event_call *call = &event->call;
914 int ret;
915
916 ret = trace_remove_event_call(call);
917
918 return ret;
919 }
920
free_synth_event(struct synth_event * event)921 static void free_synth_event(struct synth_event *event)
922 {
923 unsigned int i;
924
925 if (!event)
926 return;
927
928 for (i = 0; i < event->n_fields; i++)
929 free_synth_field(event->fields[i]);
930
931 kfree(event->fields);
932 kfree(event->dynamic_fields);
933 kfree(event->name);
934 kfree(event->class.system);
935 free_synth_tracepoint(event->tp);
936 free_synth_event_print_fmt(&event->call);
937 kfree(event);
938 }
939
alloc_synth_event(const char * name,int n_fields,struct synth_field ** fields)940 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
941 struct synth_field **fields)
942 {
943 unsigned int i, j, n_dynamic_fields = 0;
944 struct synth_event *event;
945
946 event = kzalloc(sizeof(*event), GFP_KERNEL);
947 if (!event) {
948 event = ERR_PTR(-ENOMEM);
949 goto out;
950 }
951
952 event->name = kstrdup(name, GFP_KERNEL);
953 if (!event->name) {
954 kfree(event);
955 event = ERR_PTR(-ENOMEM);
956 goto out;
957 }
958
959 event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
960 if (!event->fields) {
961 free_synth_event(event);
962 event = ERR_PTR(-ENOMEM);
963 goto out;
964 }
965
966 for (i = 0; i < n_fields; i++)
967 if (fields[i]->is_dynamic)
968 n_dynamic_fields++;
969
970 if (n_dynamic_fields) {
971 event->dynamic_fields = kcalloc(n_dynamic_fields,
972 sizeof(*event->dynamic_fields),
973 GFP_KERNEL);
974 if (!event->dynamic_fields) {
975 free_synth_event(event);
976 event = ERR_PTR(-ENOMEM);
977 goto out;
978 }
979 }
980
981 dyn_event_init(&event->devent, &synth_event_ops);
982
983 for (i = 0, j = 0; i < n_fields; i++) {
984 fields[i]->field_pos = i;
985 event->fields[i] = fields[i];
986
987 if (fields[i]->is_dynamic)
988 event->dynamic_fields[j++] = fields[i];
989 }
990 event->n_dynamic_fields = j;
991 event->n_fields = n_fields;
992 out:
993 return event;
994 }
995
synth_event_check_arg_fn(void * data)996 static int synth_event_check_arg_fn(void *data)
997 {
998 struct dynevent_arg_pair *arg_pair = data;
999 int size;
1000
1001 size = synth_field_size((char *)arg_pair->lhs);
1002 if (size == 0) {
1003 if (strstr((char *)arg_pair->lhs, "["))
1004 return 0;
1005 }
1006
1007 return size ? 0 : -EINVAL;
1008 }
1009
1010 /**
1011 * synth_event_add_field - Add a new field to a synthetic event cmd
1012 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1013 * @type: The type of the new field to add
1014 * @name: The name of the new field to add
1015 *
1016 * Add a new field to a synthetic event cmd object. Field ordering is in
1017 * the same order the fields are added.
1018 *
1019 * See synth_field_size() for available types. If field_name contains
1020 * [n] the field is considered to be an array.
1021 *
1022 * Return: 0 if successful, error otherwise.
1023 */
synth_event_add_field(struct dynevent_cmd * cmd,const char * type,const char * name)1024 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1025 const char *name)
1026 {
1027 struct dynevent_arg_pair arg_pair;
1028 int ret;
1029
1030 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1031 return -EINVAL;
1032
1033 if (!type || !name)
1034 return -EINVAL;
1035
1036 dynevent_arg_pair_init(&arg_pair, 0, ';');
1037
1038 arg_pair.lhs = type;
1039 arg_pair.rhs = name;
1040
1041 ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1042 if (ret)
1043 return ret;
1044
1045 if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1046 ret = -EINVAL;
1047
1048 return ret;
1049 }
1050 EXPORT_SYMBOL_GPL(synth_event_add_field);
1051
1052 /**
1053 * synth_event_add_field_str - Add a new field to a synthetic event cmd
1054 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1055 * @type_name: The type and name of the new field to add, as a single string
1056 *
1057 * Add a new field to a synthetic event cmd object, as a single
1058 * string. The @type_name string is expected to be of the form 'type
1059 * name', which will be appended by ';'. No sanity checking is done -
1060 * what's passed in is assumed to already be well-formed. Field
1061 * ordering is in the same order the fields are added.
1062 *
1063 * See synth_field_size() for available types. If field_name contains
1064 * [n] the field is considered to be an array.
1065 *
1066 * Return: 0 if successful, error otherwise.
1067 */
synth_event_add_field_str(struct dynevent_cmd * cmd,const char * type_name)1068 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1069 {
1070 struct dynevent_arg arg;
1071 int ret;
1072
1073 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1074 return -EINVAL;
1075
1076 if (!type_name)
1077 return -EINVAL;
1078
1079 dynevent_arg_init(&arg, ';');
1080
1081 arg.str = type_name;
1082
1083 ret = dynevent_arg_add(cmd, &arg, NULL);
1084 if (ret)
1085 return ret;
1086
1087 if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1088 ret = -EINVAL;
1089
1090 return ret;
1091 }
1092 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1093
1094 /**
1095 * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1096 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1097 * @fields: An array of type/name field descriptions
1098 * @n_fields: The number of field descriptions contained in the fields array
1099 *
1100 * Add a new set of fields to a synthetic event cmd object. The event
1101 * fields that will be defined for the event should be passed in as an
1102 * array of struct synth_field_desc, and the number of elements in the
1103 * array passed in as n_fields. Field ordering will retain the
1104 * ordering given in the fields array.
1105 *
1106 * See synth_field_size() for available types. If field_name contains
1107 * [n] the field is considered to be an array.
1108 *
1109 * Return: 0 if successful, error otherwise.
1110 */
synth_event_add_fields(struct dynevent_cmd * cmd,struct synth_field_desc * fields,unsigned int n_fields)1111 int synth_event_add_fields(struct dynevent_cmd *cmd,
1112 struct synth_field_desc *fields,
1113 unsigned int n_fields)
1114 {
1115 unsigned int i;
1116 int ret = 0;
1117
1118 for (i = 0; i < n_fields; i++) {
1119 if (fields[i].type == NULL || fields[i].name == NULL) {
1120 ret = -EINVAL;
1121 break;
1122 }
1123
1124 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1125 if (ret)
1126 break;
1127 }
1128
1129 return ret;
1130 }
1131 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1132
1133 /**
1134 * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1135 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1136 * @name: The name of the synthetic event
1137 * @mod: The module creating the event, NULL if not created from a module
1138 * @args: Variable number of arg (pairs), one pair for each field
1139 *
1140 * NOTE: Users normally won't want to call this function directly, but
1141 * rather use the synth_event_gen_cmd_start() wrapper, which
1142 * automatically adds a NULL to the end of the arg list. If this
1143 * function is used directly, make sure the last arg in the variable
1144 * arg list is NULL.
1145 *
1146 * Generate a synthetic event command to be executed by
1147 * synth_event_gen_cmd_end(). This function can be used to generate
1148 * the complete command or only the first part of it; in the latter
1149 * case, synth_event_add_field(), synth_event_add_field_str(), or
1150 * synth_event_add_fields() can be used to add more fields following
1151 * this.
1152 *
1153 * There should be an even number variable args, each pair consisting
1154 * of a type followed by a field name.
1155 *
1156 * See synth_field_size() for available types. If field_name contains
1157 * [n] the field is considered to be an array.
1158 *
1159 * Return: 0 if successful, error otherwise.
1160 */
__synth_event_gen_cmd_start(struct dynevent_cmd * cmd,const char * name,struct module * mod,...)1161 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1162 struct module *mod, ...)
1163 {
1164 struct dynevent_arg arg;
1165 va_list args;
1166 int ret;
1167
1168 cmd->event_name = name;
1169 cmd->private_data = mod;
1170
1171 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1172 return -EINVAL;
1173
1174 dynevent_arg_init(&arg, 0);
1175 arg.str = name;
1176 ret = dynevent_arg_add(cmd, &arg, NULL);
1177 if (ret)
1178 return ret;
1179
1180 va_start(args, mod);
1181 for (;;) {
1182 const char *type, *name;
1183
1184 type = va_arg(args, const char *);
1185 if (!type)
1186 break;
1187 name = va_arg(args, const char *);
1188 if (!name)
1189 break;
1190
1191 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1192 ret = -EINVAL;
1193 break;
1194 }
1195
1196 ret = synth_event_add_field(cmd, type, name);
1197 if (ret)
1198 break;
1199 }
1200 va_end(args);
1201
1202 return ret;
1203 }
1204 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1205
1206 /**
1207 * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1208 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1209 * @name: The name of the synthetic event
1210 * @fields: An array of type/name field descriptions
1211 * @n_fields: The number of field descriptions contained in the fields array
1212 *
1213 * Generate a synthetic event command to be executed by
1214 * synth_event_gen_cmd_end(). This function can be used to generate
1215 * the complete command or only the first part of it; in the latter
1216 * case, synth_event_add_field(), synth_event_add_field_str(), or
1217 * synth_event_add_fields() can be used to add more fields following
1218 * this.
1219 *
1220 * The event fields that will be defined for the event should be
1221 * passed in as an array of struct synth_field_desc, and the number of
1222 * elements in the array passed in as n_fields. Field ordering will
1223 * retain the ordering given in the fields array.
1224 *
1225 * See synth_field_size() for available types. If field_name contains
1226 * [n] the field is considered to be an array.
1227 *
1228 * Return: 0 if successful, error otherwise.
1229 */
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)1230 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1231 struct module *mod,
1232 struct synth_field_desc *fields,
1233 unsigned int n_fields)
1234 {
1235 struct dynevent_arg arg;
1236 unsigned int i;
1237 int ret = 0;
1238
1239 cmd->event_name = name;
1240 cmd->private_data = mod;
1241
1242 if (cmd->type != DYNEVENT_TYPE_SYNTH)
1243 return -EINVAL;
1244
1245 if (n_fields > SYNTH_FIELDS_MAX)
1246 return -EINVAL;
1247
1248 dynevent_arg_init(&arg, 0);
1249 arg.str = name;
1250 ret = dynevent_arg_add(cmd, &arg, NULL);
1251 if (ret)
1252 return ret;
1253
1254 for (i = 0; i < n_fields; i++) {
1255 if (fields[i].type == NULL || fields[i].name == NULL)
1256 return -EINVAL;
1257
1258 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1259 if (ret)
1260 break;
1261 }
1262
1263 return ret;
1264 }
1265 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1266
__create_synth_event(const char * name,const char * raw_fields)1267 static int __create_synth_event(const char *name, const char *raw_fields)
1268 {
1269 char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1270 struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1271 int consumed, cmd_version = 1, n_fields_this_loop;
1272 int i, argc, n_fields = 0, ret = 0;
1273 struct synth_event *event = NULL;
1274
1275 /*
1276 * Argument syntax:
1277 * - Add synthetic event: <event_name> field[;field] ...
1278 * - Remove synthetic event: !<event_name> field[;field] ...
1279 * where 'field' = type field_name
1280 */
1281
1282 if (name[0] == '\0') {
1283 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1284 return -EINVAL;
1285 }
1286
1287 if (!is_good_name(name)) {
1288 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1289 return -EINVAL;
1290 }
1291
1292 mutex_lock(&event_mutex);
1293
1294 event = find_synth_event(name);
1295 if (event) {
1296 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1297 ret = -EEXIST;
1298 goto err;
1299 }
1300
1301 tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1302 if (!tmp_fields) {
1303 ret = -ENOMEM;
1304 goto err;
1305 }
1306
1307 while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1308 argv = argv_split(GFP_KERNEL, field_str, &argc);
1309 if (!argv) {
1310 ret = -ENOMEM;
1311 goto err;
1312 }
1313
1314 if (!argc) {
1315 argv_free(argv);
1316 continue;
1317 }
1318
1319 n_fields_this_loop = 0;
1320 consumed = 0;
1321 while (argc > consumed) {
1322 int field_version;
1323
1324 field = parse_synth_field(argc - consumed,
1325 argv + consumed, &consumed,
1326 &field_version);
1327 if (IS_ERR(field)) {
1328 argv_free(argv);
1329 ret = PTR_ERR(field);
1330 goto err;
1331 }
1332
1333 /*
1334 * Track the highest version of any field we
1335 * found in the command.
1336 */
1337 if (field_version > cmd_version)
1338 cmd_version = field_version;
1339
1340 /*
1341 * Now sort out what is and isn't valid for
1342 * each supported version.
1343 *
1344 * If we see more than 1 field per loop, it
1345 * means we have multiple fields between
1346 * semicolons, and that's something we no
1347 * longer support in a version 2 or greater
1348 * command.
1349 */
1350 if (cmd_version > 1 && n_fields_this_loop >= 1) {
1351 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1352 ret = -EINVAL;
1353 goto err;
1354 }
1355
1356 if (n_fields == SYNTH_FIELDS_MAX) {
1357 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1358 ret = -EINVAL;
1359 goto err;
1360 }
1361 fields[n_fields++] = field;
1362
1363 n_fields_this_loop++;
1364 }
1365
1366 if (consumed < argc) {
1367 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1368 ret = -EINVAL;
1369 goto err;
1370 }
1371
1372 argv_free(argv);
1373 }
1374
1375 if (n_fields == 0) {
1376 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1377 ret = -EINVAL;
1378 goto err;
1379 }
1380
1381 event = alloc_synth_event(name, n_fields, fields);
1382 if (IS_ERR(event)) {
1383 ret = PTR_ERR(event);
1384 event = NULL;
1385 goto err;
1386 }
1387 ret = register_synth_event(event);
1388 if (!ret)
1389 dyn_event_add(&event->devent, &event->call);
1390 else
1391 free_synth_event(event);
1392 out:
1393 mutex_unlock(&event_mutex);
1394
1395 kfree(saved_fields);
1396
1397 return ret;
1398 err:
1399 for (i = 0; i < n_fields; i++)
1400 free_synth_field(fields[i]);
1401
1402 goto out;
1403 }
1404
1405 /**
1406 * synth_event_create - Create a new synthetic event
1407 * @name: The name of the new synthetic event
1408 * @fields: An array of type/name field descriptions
1409 * @n_fields: The number of field descriptions contained in the fields array
1410 * @mod: The module creating the event, NULL if not created from a module
1411 *
1412 * Create a new synthetic event with the given name under the
1413 * trace/events/synthetic/ directory. The event fields that will be
1414 * defined for the event should be passed in as an array of struct
1415 * synth_field_desc, and the number elements in the array passed in as
1416 * n_fields. Field ordering will retain the ordering given in the
1417 * fields array.
1418 *
1419 * If the new synthetic event is being created from a module, the mod
1420 * param must be non-NULL. This will ensure that the trace buffer
1421 * won't contain unreadable events.
1422 *
1423 * The new synth event should be deleted using synth_event_delete()
1424 * function. The new synthetic event can be generated from modules or
1425 * other kernel code using trace_synth_event() and related functions.
1426 *
1427 * Return: 0 if successful, error otherwise.
1428 */
synth_event_create(const char * name,struct synth_field_desc * fields,unsigned int n_fields,struct module * mod)1429 int synth_event_create(const char *name, struct synth_field_desc *fields,
1430 unsigned int n_fields, struct module *mod)
1431 {
1432 struct dynevent_cmd cmd;
1433 char *buf;
1434 int ret;
1435
1436 buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1437 if (!buf)
1438 return -ENOMEM;
1439
1440 synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1441
1442 ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1443 fields, n_fields);
1444 if (ret)
1445 goto out;
1446
1447 ret = synth_event_gen_cmd_end(&cmd);
1448 out:
1449 kfree(buf);
1450
1451 return ret;
1452 }
1453 EXPORT_SYMBOL_GPL(synth_event_create);
1454
destroy_synth_event(struct synth_event * se)1455 static int destroy_synth_event(struct synth_event *se)
1456 {
1457 int ret;
1458
1459 if (se->ref)
1460 return -EBUSY;
1461
1462 if (trace_event_dyn_busy(&se->call))
1463 return -EBUSY;
1464
1465 ret = unregister_synth_event(se);
1466 if (!ret) {
1467 dyn_event_remove(&se->devent);
1468 free_synth_event(se);
1469 }
1470
1471 return ret;
1472 }
1473
1474 /**
1475 * synth_event_delete - Delete a synthetic event
1476 * @event_name: The name of the new synthetic event
1477 *
1478 * Delete a synthetic event that was created with synth_event_create().
1479 *
1480 * Return: 0 if successful, error otherwise.
1481 */
synth_event_delete(const char * event_name)1482 int synth_event_delete(const char *event_name)
1483 {
1484 struct synth_event *se = NULL;
1485 struct module *mod = NULL;
1486 int ret = -ENOENT;
1487
1488 mutex_lock(&event_mutex);
1489 se = find_synth_event(event_name);
1490 if (se) {
1491 mod = se->mod;
1492 ret = destroy_synth_event(se);
1493 }
1494 mutex_unlock(&event_mutex);
1495
1496 if (mod) {
1497 /*
1498 * It is safest to reset the ring buffer if the module
1499 * being unloaded registered any events that were
1500 * used. The only worry is if a new module gets
1501 * loaded, and takes on the same id as the events of
1502 * this module. When printing out the buffer, traced
1503 * events left over from this module may be passed to
1504 * the new module events and unexpected results may
1505 * occur.
1506 */
1507 tracing_reset_all_online_cpus();
1508 }
1509
1510 return ret;
1511 }
1512 EXPORT_SYMBOL_GPL(synth_event_delete);
1513
check_command(const char * raw_command)1514 static int check_command(const char *raw_command)
1515 {
1516 char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1517 int argc, ret = 0;
1518
1519 cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1520 if (!cmd)
1521 return -ENOMEM;
1522
1523 name_and_field = strsep(&cmd, ";");
1524 if (!name_and_field) {
1525 ret = -EINVAL;
1526 goto free;
1527 }
1528
1529 if (name_and_field[0] == '!')
1530 goto free;
1531
1532 argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1533 if (!argv) {
1534 ret = -ENOMEM;
1535 goto free;
1536 }
1537 argv_free(argv);
1538
1539 if (argc < 3)
1540 ret = -EINVAL;
1541 free:
1542 kfree(saved_cmd);
1543
1544 return ret;
1545 }
1546
create_or_delete_synth_event(const char * raw_command)1547 static int create_or_delete_synth_event(const char *raw_command)
1548 {
1549 char *name = NULL, *fields, *p;
1550 int ret = 0;
1551
1552 raw_command = skip_spaces(raw_command);
1553 if (raw_command[0] == '\0')
1554 return ret;
1555
1556 last_cmd_set(raw_command);
1557
1558 ret = check_command(raw_command);
1559 if (ret) {
1560 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1561 return ret;
1562 }
1563
1564 p = strpbrk(raw_command, " \t");
1565 if (!p && raw_command[0] != '!') {
1566 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1567 ret = -EINVAL;
1568 goto free;
1569 }
1570
1571 name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1572 if (!name)
1573 return -ENOMEM;
1574
1575 if (name[0] == '!') {
1576 ret = synth_event_delete(name + 1);
1577 goto free;
1578 }
1579
1580 fields = skip_spaces(p);
1581
1582 ret = __create_synth_event(name, fields);
1583 free:
1584 kfree(name);
1585
1586 return ret;
1587 }
1588
synth_event_run_command(struct dynevent_cmd * cmd)1589 static int synth_event_run_command(struct dynevent_cmd *cmd)
1590 {
1591 struct synth_event *se;
1592 int ret;
1593
1594 ret = create_or_delete_synth_event(cmd->seq.buffer);
1595 if (ret)
1596 return ret;
1597
1598 se = find_synth_event(cmd->event_name);
1599 if (WARN_ON(!se))
1600 return -ENOENT;
1601
1602 se->mod = cmd->private_data;
1603
1604 return ret;
1605 }
1606
1607 /**
1608 * synth_event_cmd_init - Initialize a synthetic event command object
1609 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1610 * @buf: A pointer to the buffer used to build the command
1611 * @maxlen: The length of the buffer passed in @buf
1612 *
1613 * Initialize a synthetic event command object. Use this before
1614 * calling any of the other dyenvent_cmd functions.
1615 */
synth_event_cmd_init(struct dynevent_cmd * cmd,char * buf,int maxlen)1616 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1617 {
1618 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1619 synth_event_run_command);
1620 }
1621 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1622
1623 static inline int
__synth_event_trace_init(struct trace_event_file * file,struct synth_event_trace_state * trace_state)1624 __synth_event_trace_init(struct trace_event_file *file,
1625 struct synth_event_trace_state *trace_state)
1626 {
1627 int ret = 0;
1628
1629 memset(trace_state, '\0', sizeof(*trace_state));
1630
1631 /*
1632 * Normal event tracing doesn't get called at all unless the
1633 * ENABLED bit is set (which attaches the probe thus allowing
1634 * this code to be called, etc). Because this is called
1635 * directly by the user, we don't have that but we still need
1636 * to honor not logging when disabled. For the iterated
1637 * trace case, we save the enabled state upon start and just
1638 * ignore the following data calls.
1639 */
1640 if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1641 trace_trigger_soft_disabled(file)) {
1642 trace_state->disabled = true;
1643 ret = -ENOENT;
1644 goto out;
1645 }
1646
1647 trace_state->event = file->event_call->data;
1648 out:
1649 return ret;
1650 }
1651
1652 static inline int
__synth_event_trace_start(struct trace_event_file * file,struct synth_event_trace_state * trace_state,int dynamic_fields_size)1653 __synth_event_trace_start(struct trace_event_file *file,
1654 struct synth_event_trace_state *trace_state,
1655 int dynamic_fields_size)
1656 {
1657 int entry_size, fields_size = 0;
1658 int ret = 0;
1659
1660 fields_size = trace_state->event->n_u64 * sizeof(u64);
1661 fields_size += dynamic_fields_size;
1662
1663 /*
1664 * Avoid ring buffer recursion detection, as this event
1665 * is being performed within another event.
1666 */
1667 trace_state->buffer = file->tr->array_buffer.buffer;
1668 ring_buffer_nest_start(trace_state->buffer);
1669
1670 entry_size = sizeof(*trace_state->entry) + fields_size;
1671 trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1672 file,
1673 entry_size);
1674 if (!trace_state->entry) {
1675 ring_buffer_nest_end(trace_state->buffer);
1676 ret = -EINVAL;
1677 }
1678
1679 return ret;
1680 }
1681
1682 static inline void
__synth_event_trace_end(struct synth_event_trace_state * trace_state)1683 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1684 {
1685 trace_event_buffer_commit(&trace_state->fbuffer);
1686
1687 ring_buffer_nest_end(trace_state->buffer);
1688 }
1689
1690 /**
1691 * synth_event_trace - Trace a synthetic event
1692 * @file: The trace_event_file representing the synthetic event
1693 * @n_vals: The number of values in vals
1694 * @args: Variable number of args containing the event values
1695 *
1696 * Trace a synthetic event using the values passed in the variable
1697 * argument list.
1698 *
1699 * The argument list should be a list 'n_vals' u64 values. The number
1700 * of vals must match the number of field in the synthetic event, and
1701 * must be in the same order as the synthetic event fields.
1702 *
1703 * All vals should be cast to u64, and string vals are just pointers
1704 * to strings, cast to u64. Strings will be copied into space
1705 * reserved in the event for the string, using these pointers.
1706 *
1707 * Return: 0 on success, err otherwise.
1708 */
synth_event_trace(struct trace_event_file * file,unsigned int n_vals,...)1709 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1710 {
1711 unsigned int i, n_u64, len, data_size = 0;
1712 struct synth_event_trace_state state;
1713 va_list args;
1714 int ret;
1715
1716 ret = __synth_event_trace_init(file, &state);
1717 if (ret) {
1718 if (ret == -ENOENT)
1719 ret = 0; /* just disabled, not really an error */
1720 return ret;
1721 }
1722
1723 if (state.event->n_dynamic_fields) {
1724 va_start(args, n_vals);
1725
1726 for (i = 0; i < state.event->n_fields; i++) {
1727 u64 val = va_arg(args, u64);
1728
1729 if (state.event->fields[i]->is_string &&
1730 state.event->fields[i]->is_dynamic) {
1731 char *str_val = (char *)(long)val;
1732
1733 data_size += strlen(str_val) + 1;
1734 }
1735 }
1736
1737 va_end(args);
1738 }
1739
1740 ret = __synth_event_trace_start(file, &state, data_size);
1741 if (ret)
1742 return ret;
1743
1744 if (n_vals != state.event->n_fields) {
1745 ret = -EINVAL;
1746 goto out;
1747 }
1748
1749 data_size = 0;
1750
1751 va_start(args, n_vals);
1752 for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1753 u64 val;
1754
1755 val = va_arg(args, u64);
1756
1757 if (state.event->fields[i]->is_string) {
1758 char *str_val = (char *)(long)val;
1759
1760 len = trace_string(state.entry, state.event, str_val,
1761 state.event->fields[i]->is_dynamic,
1762 data_size, &n_u64);
1763 data_size += len; /* only dynamic string increments */
1764 } else {
1765 struct synth_field *field = state.event->fields[i];
1766
1767 switch (field->size) {
1768 case 1:
1769 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1770 break;
1771
1772 case 2:
1773 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1774 break;
1775
1776 case 4:
1777 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1778 break;
1779
1780 default:
1781 state.entry->fields[n_u64] = val;
1782 break;
1783 }
1784 n_u64++;
1785 }
1786 }
1787 va_end(args);
1788 out:
1789 __synth_event_trace_end(&state);
1790
1791 return ret;
1792 }
1793 EXPORT_SYMBOL_GPL(synth_event_trace);
1794
1795 /**
1796 * synth_event_trace_array - Trace a synthetic event from an array
1797 * @file: The trace_event_file representing the synthetic event
1798 * @vals: Array of values
1799 * @n_vals: The number of values in vals
1800 *
1801 * Trace a synthetic event using the values passed in as 'vals'.
1802 *
1803 * The 'vals' array is just an array of 'n_vals' u64. The number of
1804 * vals must match the number of field in the synthetic event, and
1805 * must be in the same order as the synthetic event fields.
1806 *
1807 * All vals should be cast to u64, and string vals are just pointers
1808 * to strings, cast to u64. Strings will be copied into space
1809 * reserved in the event for the string, using these pointers.
1810 *
1811 * Return: 0 on success, err otherwise.
1812 */
synth_event_trace_array(struct trace_event_file * file,u64 * vals,unsigned int n_vals)1813 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1814 unsigned int n_vals)
1815 {
1816 unsigned int i, n_u64, field_pos, len, data_size = 0;
1817 struct synth_event_trace_state state;
1818 char *str_val;
1819 int ret;
1820
1821 ret = __synth_event_trace_init(file, &state);
1822 if (ret) {
1823 if (ret == -ENOENT)
1824 ret = 0; /* just disabled, not really an error */
1825 return ret;
1826 }
1827
1828 if (state.event->n_dynamic_fields) {
1829 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1830 field_pos = state.event->dynamic_fields[i]->field_pos;
1831 str_val = (char *)(long)vals[field_pos];
1832 len = strlen(str_val) + 1;
1833 data_size += len;
1834 }
1835 }
1836
1837 ret = __synth_event_trace_start(file, &state, data_size);
1838 if (ret)
1839 return ret;
1840
1841 if (n_vals != state.event->n_fields) {
1842 ret = -EINVAL;
1843 goto out;
1844 }
1845
1846 data_size = 0;
1847
1848 for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1849 if (state.event->fields[i]->is_string) {
1850 char *str_val = (char *)(long)vals[i];
1851
1852 len = trace_string(state.entry, state.event, str_val,
1853 state.event->fields[i]->is_dynamic,
1854 data_size, &n_u64);
1855 data_size += len; /* only dynamic string increments */
1856 } else {
1857 struct synth_field *field = state.event->fields[i];
1858 u64 val = vals[i];
1859
1860 switch (field->size) {
1861 case 1:
1862 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1863 break;
1864
1865 case 2:
1866 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1867 break;
1868
1869 case 4:
1870 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1871 break;
1872
1873 default:
1874 state.entry->fields[n_u64] = val;
1875 break;
1876 }
1877 n_u64++;
1878 }
1879 }
1880 out:
1881 __synth_event_trace_end(&state);
1882
1883 return ret;
1884 }
1885 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1886
1887 /**
1888 * synth_event_trace_start - Start piecewise synthetic event trace
1889 * @file: The trace_event_file representing the synthetic event
1890 * @trace_state: A pointer to object tracking the piecewise trace state
1891 *
1892 * Start the trace of a synthetic event field-by-field rather than all
1893 * at once.
1894 *
1895 * This function 'opens' an event trace, which means space is reserved
1896 * for the event in the trace buffer, after which the event's
1897 * individual field values can be set through either
1898 * synth_event_add_next_val() or synth_event_add_val().
1899 *
1900 * A pointer to a trace_state object is passed in, which will keep
1901 * track of the current event trace state until the event trace is
1902 * closed (and the event finally traced) using
1903 * synth_event_trace_end().
1904 *
1905 * Note that synth_event_trace_end() must be called after all values
1906 * have been added for each event trace, regardless of whether adding
1907 * all field values succeeded or not.
1908 *
1909 * Note also that for a given event trace, all fields must be added
1910 * using either synth_event_add_next_val() or synth_event_add_val()
1911 * but not both together or interleaved.
1912 *
1913 * Return: 0 on success, err otherwise.
1914 */
synth_event_trace_start(struct trace_event_file * file,struct synth_event_trace_state * trace_state)1915 int synth_event_trace_start(struct trace_event_file *file,
1916 struct synth_event_trace_state *trace_state)
1917 {
1918 int ret;
1919
1920 if (!trace_state)
1921 return -EINVAL;
1922
1923 ret = __synth_event_trace_init(file, trace_state);
1924 if (ret) {
1925 if (ret == -ENOENT)
1926 ret = 0; /* just disabled, not really an error */
1927 return ret;
1928 }
1929
1930 if (trace_state->event->n_dynamic_fields)
1931 return -ENOTSUPP;
1932
1933 ret = __synth_event_trace_start(file, trace_state, 0);
1934
1935 return ret;
1936 }
1937 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1938
__synth_event_add_val(const char * field_name,u64 val,struct synth_event_trace_state * trace_state)1939 static int __synth_event_add_val(const char *field_name, u64 val,
1940 struct synth_event_trace_state *trace_state)
1941 {
1942 struct synth_field *field = NULL;
1943 struct synth_trace_event *entry;
1944 struct synth_event *event;
1945 int i, ret = 0;
1946
1947 if (!trace_state) {
1948 ret = -EINVAL;
1949 goto out;
1950 }
1951
1952 /* can't mix add_next_synth_val() with add_synth_val() */
1953 if (field_name) {
1954 if (trace_state->add_next) {
1955 ret = -EINVAL;
1956 goto out;
1957 }
1958 trace_state->add_name = true;
1959 } else {
1960 if (trace_state->add_name) {
1961 ret = -EINVAL;
1962 goto out;
1963 }
1964 trace_state->add_next = true;
1965 }
1966
1967 if (trace_state->disabled)
1968 goto out;
1969
1970 event = trace_state->event;
1971 if (trace_state->add_name) {
1972 for (i = 0; i < event->n_fields; i++) {
1973 field = event->fields[i];
1974 if (strcmp(field->name, field_name) == 0)
1975 break;
1976 }
1977 if (!field) {
1978 ret = -EINVAL;
1979 goto out;
1980 }
1981 } else {
1982 if (trace_state->cur_field >= event->n_fields) {
1983 ret = -EINVAL;
1984 goto out;
1985 }
1986 field = event->fields[trace_state->cur_field++];
1987 }
1988
1989 entry = trace_state->entry;
1990 if (field->is_string) {
1991 char *str_val = (char *)(long)val;
1992 char *str_field;
1993
1994 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1995 ret = -EINVAL;
1996 goto out;
1997 }
1998
1999 if (!str_val) {
2000 ret = -EINVAL;
2001 goto out;
2002 }
2003
2004 str_field = (char *)&entry->fields[field->offset];
2005 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2006 } else {
2007 switch (field->size) {
2008 case 1:
2009 *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
2010 break;
2011
2012 case 2:
2013 *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
2014 break;
2015
2016 case 4:
2017 *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
2018 break;
2019
2020 default:
2021 trace_state->entry->fields[field->offset] = val;
2022 break;
2023 }
2024 }
2025 out:
2026 return ret;
2027 }
2028
2029 /**
2030 * synth_event_add_next_val - Add the next field's value to an open synth trace
2031 * @val: The value to set the next field to
2032 * @trace_state: A pointer to object tracking the piecewise trace state
2033 *
2034 * Set the value of the next field in an event that's been opened by
2035 * synth_event_trace_start().
2036 *
2037 * The val param should be the value cast to u64. If the value points
2038 * to a string, the val param should be a char * cast to u64.
2039 *
2040 * This function assumes all the fields in an event are to be set one
2041 * after another - successive calls to this function are made, one for
2042 * each field, in the order of the fields in the event, until all
2043 * fields have been set. If you'd rather set each field individually
2044 * without regard to ordering, synth_event_add_val() can be used
2045 * instead.
2046 *
2047 * Note however that synth_event_add_next_val() and
2048 * synth_event_add_val() can't be intermixed for a given event trace -
2049 * one or the other but not both can be used at the same time.
2050 *
2051 * Note also that synth_event_trace_end() must be called after all
2052 * values have been added for each event trace, regardless of whether
2053 * adding all field values succeeded or not.
2054 *
2055 * Return: 0 on success, err otherwise.
2056 */
synth_event_add_next_val(u64 val,struct synth_event_trace_state * trace_state)2057 int synth_event_add_next_val(u64 val,
2058 struct synth_event_trace_state *trace_state)
2059 {
2060 return __synth_event_add_val(NULL, val, trace_state);
2061 }
2062 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2063
2064 /**
2065 * synth_event_add_val - Add a named field's value to an open synth trace
2066 * @field_name: The name of the synthetic event field value to set
2067 * @val: The value to set the next field to
2068 * @trace_state: A pointer to object tracking the piecewise trace state
2069 *
2070 * Set the value of the named field in an event that's been opened by
2071 * synth_event_trace_start().
2072 *
2073 * The val param should be the value cast to u64. If the value points
2074 * to a string, the val param should be a char * cast to u64.
2075 *
2076 * This function looks up the field name, and if found, sets the field
2077 * to the specified value. This lookup makes this function more
2078 * expensive than synth_event_add_next_val(), so use that or the
2079 * none-piecewise synth_event_trace() instead if efficiency is more
2080 * important.
2081 *
2082 * Note however that synth_event_add_next_val() and
2083 * synth_event_add_val() can't be intermixed for a given event trace -
2084 * one or the other but not both can be used at the same time.
2085 *
2086 * Note also that synth_event_trace_end() must be called after all
2087 * values have been added for each event trace, regardless of whether
2088 * adding all field values succeeded or not.
2089 *
2090 * Return: 0 on success, err otherwise.
2091 */
synth_event_add_val(const char * field_name,u64 val,struct synth_event_trace_state * trace_state)2092 int synth_event_add_val(const char *field_name, u64 val,
2093 struct synth_event_trace_state *trace_state)
2094 {
2095 return __synth_event_add_val(field_name, val, trace_state);
2096 }
2097 EXPORT_SYMBOL_GPL(synth_event_add_val);
2098
2099 /**
2100 * synth_event_trace_end - End piecewise synthetic event trace
2101 * @trace_state: A pointer to object tracking the piecewise trace state
2102 *
2103 * End the trace of a synthetic event opened by
2104 * synth_event_trace__start().
2105 *
2106 * This function 'closes' an event trace, which basically means that
2107 * it commits the reserved event and cleans up other loose ends.
2108 *
2109 * A pointer to a trace_state object is passed in, which will keep
2110 * track of the current event trace state opened with
2111 * synth_event_trace_start().
2112 *
2113 * Note that this function must be called after all values have been
2114 * added for each event trace, regardless of whether adding all field
2115 * values succeeded or not.
2116 *
2117 * Return: 0 on success, err otherwise.
2118 */
synth_event_trace_end(struct synth_event_trace_state * trace_state)2119 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2120 {
2121 if (!trace_state)
2122 return -EINVAL;
2123
2124 __synth_event_trace_end(trace_state);
2125
2126 return 0;
2127 }
2128 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2129
create_synth_event(const char * raw_command)2130 static int create_synth_event(const char *raw_command)
2131 {
2132 char *fields, *p;
2133 const char *name;
2134 int len, ret = 0;
2135
2136 raw_command = skip_spaces(raw_command);
2137 if (raw_command[0] == '\0')
2138 return ret;
2139
2140 last_cmd_set(raw_command);
2141
2142 name = raw_command;
2143
2144 /* Don't try to process if not our system */
2145 if (name[0] != 's' || name[1] != ':')
2146 return -ECANCELED;
2147 name += 2;
2148
2149 p = strpbrk(raw_command, " \t");
2150 if (!p) {
2151 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2152 return -EINVAL;
2153 }
2154
2155 fields = skip_spaces(p);
2156
2157 /* This interface accepts group name prefix */
2158 if (strchr(name, '/')) {
2159 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2160 if (len == 0) {
2161 synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2162 return -EINVAL;
2163 }
2164 name += len;
2165 }
2166
2167 len = name - raw_command;
2168
2169 ret = check_command(raw_command + len);
2170 if (ret) {
2171 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2172 return ret;
2173 }
2174
2175 name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2176 if (!name)
2177 return -ENOMEM;
2178
2179 ret = __create_synth_event(name, fields);
2180
2181 kfree(name);
2182
2183 return ret;
2184 }
2185
synth_event_release(struct dyn_event * ev)2186 static int synth_event_release(struct dyn_event *ev)
2187 {
2188 struct synth_event *event = to_synth_event(ev);
2189 int ret;
2190
2191 if (event->ref)
2192 return -EBUSY;
2193
2194 if (trace_event_dyn_busy(&event->call))
2195 return -EBUSY;
2196
2197 ret = unregister_synth_event(event);
2198 if (ret)
2199 return ret;
2200
2201 dyn_event_remove(ev);
2202 free_synth_event(event);
2203 return 0;
2204 }
2205
__synth_event_show(struct seq_file * m,struct synth_event * event)2206 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2207 {
2208 struct synth_field *field;
2209 unsigned int i;
2210 char *type, *t;
2211
2212 seq_printf(m, "%s\t", event->name);
2213
2214 for (i = 0; i < event->n_fields; i++) {
2215 field = event->fields[i];
2216
2217 type = field->type;
2218 t = strstr(type, "__data_loc");
2219 if (t) { /* __data_loc belongs in format but not event desc */
2220 t += sizeof("__data_loc");
2221 type = t;
2222 }
2223
2224 /* parameter values */
2225 seq_printf(m, "%s %s%s", type, field->name,
2226 i == event->n_fields - 1 ? "" : "; ");
2227 }
2228
2229 seq_putc(m, '\n');
2230
2231 return 0;
2232 }
2233
synth_event_show(struct seq_file * m,struct dyn_event * ev)2234 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2235 {
2236 struct synth_event *event = to_synth_event(ev);
2237
2238 seq_printf(m, "s:%s/", event->class.system);
2239
2240 return __synth_event_show(m, event);
2241 }
2242
synth_events_seq_show(struct seq_file * m,void * v)2243 static int synth_events_seq_show(struct seq_file *m, void *v)
2244 {
2245 struct dyn_event *ev = v;
2246
2247 if (!is_synth_event(ev))
2248 return 0;
2249
2250 return __synth_event_show(m, to_synth_event(ev));
2251 }
2252
2253 static const struct seq_operations synth_events_seq_op = {
2254 .start = dyn_event_seq_start,
2255 .next = dyn_event_seq_next,
2256 .stop = dyn_event_seq_stop,
2257 .show = synth_events_seq_show,
2258 };
2259
synth_events_open(struct inode * inode,struct file * file)2260 static int synth_events_open(struct inode *inode, struct file *file)
2261 {
2262 int ret;
2263
2264 ret = security_locked_down(LOCKDOWN_TRACEFS);
2265 if (ret)
2266 return ret;
2267
2268 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2269 ret = dyn_events_release_all(&synth_event_ops);
2270 if (ret < 0)
2271 return ret;
2272 }
2273
2274 return seq_open(file, &synth_events_seq_op);
2275 }
2276
synth_events_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)2277 static ssize_t synth_events_write(struct file *file,
2278 const char __user *buffer,
2279 size_t count, loff_t *ppos)
2280 {
2281 return trace_parse_run_command(file, buffer, count, ppos,
2282 create_or_delete_synth_event);
2283 }
2284
2285 static const struct file_operations synth_events_fops = {
2286 .open = synth_events_open,
2287 .write = synth_events_write,
2288 .read = seq_read,
2289 .llseek = seq_lseek,
2290 .release = seq_release,
2291 };
2292
2293 /*
2294 * Register dynevent at core_initcall. This allows kernel to setup kprobe
2295 * events in postcore_initcall without tracefs.
2296 */
trace_events_synth_init_early(void)2297 static __init int trace_events_synth_init_early(void)
2298 {
2299 int err = 0;
2300
2301 err = dyn_event_register(&synth_event_ops);
2302 if (err)
2303 pr_warn("Could not register synth_event_ops\n");
2304
2305 return err;
2306 }
2307 core_initcall(trace_events_synth_init_early);
2308
trace_events_synth_init(void)2309 static __init int trace_events_synth_init(void)
2310 {
2311 struct dentry *entry = NULL;
2312 int err = 0;
2313 err = tracing_init_dentry();
2314 if (err)
2315 goto err;
2316
2317 entry = tracefs_create_file("synthetic_events", 0644, NULL,
2318 NULL, &synth_events_fops);
2319 if (!entry) {
2320 err = -ENODEV;
2321 goto err;
2322 }
2323
2324 return err;
2325 err:
2326 pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2327
2328 return err;
2329 }
2330
2331 fs_initcall(trace_events_synth_init);
2332