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7491e2c4 TSV |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * event probes | |
4 | * | |
5 | * Part of this code was copied from kernel/trace/trace_kprobe.c written by | |
6 | * Masami Hiramatsu <mhiramat@kernel.org> | |
7 | * | |
8 | * Copyright (C) 2021, VMware Inc, Steven Rostedt <rostedt@goodmis.org> | |
9 | * Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com> | |
10 | * | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/ftrace.h> | |
15 | ||
16 | #include "trace_dynevent.h" | |
17 | #include "trace_probe.h" | |
18 | #include "trace_probe_tmpl.h" | |
19 | ||
20 | #define EPROBE_EVENT_SYSTEM "eprobes" | |
21 | ||
22 | struct trace_eprobe { | |
23 | /* tracepoint system */ | |
24 | const char *event_system; | |
25 | ||
26 | /* tracepoint event */ | |
27 | const char *event_name; | |
28 | ||
29 | struct trace_event_call *event; | |
30 | ||
31 | struct dyn_event devent; | |
32 | struct trace_probe tp; | |
33 | }; | |
34 | ||
35 | struct eprobe_data { | |
36 | struct trace_event_file *file; | |
37 | struct trace_eprobe *ep; | |
38 | }; | |
39 | ||
40 | static int __trace_eprobe_create(int argc, const char *argv[]); | |
41 | ||
42 | static void trace_event_probe_cleanup(struct trace_eprobe *ep) | |
43 | { | |
44 | if (!ep) | |
45 | return; | |
46 | trace_probe_cleanup(&ep->tp); | |
47 | kfree(ep->event_name); | |
48 | kfree(ep->event_system); | |
49 | if (ep->event) | |
50 | trace_event_put_ref(ep->event); | |
51 | kfree(ep); | |
52 | } | |
53 | ||
54 | static struct trace_eprobe *to_trace_eprobe(struct dyn_event *ev) | |
55 | { | |
56 | return container_of(ev, struct trace_eprobe, devent); | |
57 | } | |
58 | ||
59 | static int eprobe_dyn_event_create(const char *raw_command) | |
60 | { | |
61 | return trace_probe_create(raw_command, __trace_eprobe_create); | |
62 | } | |
63 | ||
64 | static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev) | |
65 | { | |
66 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
67 | int i; | |
68 | ||
69 | seq_printf(m, "e:%s/%s", trace_probe_group_name(&ep->tp), | |
70 | trace_probe_name(&ep->tp)); | |
71 | seq_printf(m, " %s.%s", ep->event_system, ep->event_name); | |
72 | ||
73 | for (i = 0; i < ep->tp.nr_args; i++) | |
74 | seq_printf(m, " %s=%s", ep->tp.args[i].name, ep->tp.args[i].comm); | |
75 | seq_putc(m, '\n'); | |
76 | ||
77 | return 0; | |
78 | } | |
79 | ||
80 | static int unregister_trace_eprobe(struct trace_eprobe *ep) | |
81 | { | |
82 | /* If other probes are on the event, just unregister eprobe */ | |
83 | if (trace_probe_has_sibling(&ep->tp)) | |
84 | goto unreg; | |
85 | ||
86 | /* Enabled event can not be unregistered */ | |
87 | if (trace_probe_is_enabled(&ep->tp)) | |
88 | return -EBUSY; | |
89 | ||
90 | /* Will fail if probe is being used by ftrace or perf */ | |
91 | if (trace_probe_unregister_event_call(&ep->tp)) | |
92 | return -EBUSY; | |
93 | ||
94 | unreg: | |
95 | dyn_event_remove(&ep->devent); | |
96 | trace_probe_unlink(&ep->tp); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | static int eprobe_dyn_event_release(struct dyn_event *ev) | |
102 | { | |
103 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
104 | int ret = unregister_trace_eprobe(ep); | |
105 | ||
106 | if (!ret) | |
107 | trace_event_probe_cleanup(ep); | |
108 | return ret; | |
109 | } | |
110 | ||
111 | static bool eprobe_dyn_event_is_busy(struct dyn_event *ev) | |
112 | { | |
113 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
114 | ||
115 | return trace_probe_is_enabled(&ep->tp); | |
116 | } | |
117 | ||
118 | static bool eprobe_dyn_event_match(const char *system, const char *event, | |
119 | int argc, const char **argv, struct dyn_event *ev) | |
120 | { | |
121 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
7d5fda1c SRV |
122 | const char *slash; |
123 | ||
124 | /* | |
125 | * We match the following: | |
126 | * event only - match all eprobes with event name | |
127 | * system and event only - match all system/event probes | |
128 | * | |
129 | * The below has the above satisfied with more arguments: | |
130 | * | |
131 | * attached system/event - If the arg has the system and event | |
132 | * the probe is attached to, match | |
133 | * probes with the attachment. | |
134 | * | |
135 | * If any more args are given, then it requires a full match. | |
136 | */ | |
137 | ||
138 | /* | |
139 | * If system exists, but this probe is not part of that system | |
140 | * do not match. | |
141 | */ | |
142 | if (system && strcmp(trace_probe_group_name(&ep->tp), system) != 0) | |
143 | return false; | |
144 | ||
145 | /* Must match the event name */ | |
146 | if (strcmp(trace_probe_name(&ep->tp), event) != 0) | |
147 | return false; | |
148 | ||
149 | /* No arguments match all */ | |
150 | if (argc < 1) | |
151 | return true; | |
152 | ||
153 | /* First argument is the system/event the probe is attached to */ | |
154 | ||
155 | slash = strchr(argv[0], '/'); | |
156 | if (!slash) | |
157 | slash = strchr(argv[0], '.'); | |
158 | if (!slash) | |
159 | return false; | |
160 | ||
161 | if (strncmp(ep->event_system, argv[0], slash - argv[0])) | |
162 | return false; | |
163 | if (strcmp(ep->event_name, slash + 1)) | |
164 | return false; | |
165 | ||
166 | argc--; | |
167 | argv++; | |
168 | ||
169 | /* If there are no other args, then match */ | |
170 | if (argc < 1) | |
171 | return true; | |
172 | ||
173 | return trace_probe_match_command_args(&ep->tp, argc, argv); | |
7491e2c4 TSV |
174 | } |
175 | ||
176 | static struct dyn_event_operations eprobe_dyn_event_ops = { | |
177 | .create = eprobe_dyn_event_create, | |
178 | .show = eprobe_dyn_event_show, | |
179 | .is_busy = eprobe_dyn_event_is_busy, | |
180 | .free = eprobe_dyn_event_release, | |
181 | .match = eprobe_dyn_event_match, | |
182 | }; | |
183 | ||
184 | static struct trace_eprobe *alloc_event_probe(const char *group, | |
185 | const char *this_event, | |
186 | struct trace_event_call *event, | |
187 | int nargs) | |
188 | { | |
189 | struct trace_eprobe *ep; | |
190 | const char *event_name; | |
191 | const char *sys_name; | |
192 | int ret = -ENOMEM; | |
193 | ||
194 | if (!event) | |
195 | return ERR_PTR(-ENODEV); | |
196 | ||
197 | sys_name = event->class->system; | |
198 | event_name = trace_event_name(event); | |
199 | ||
200 | ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL); | |
201 | if (!ep) { | |
5615e088 | 202 | trace_event_put_ref(event); |
7491e2c4 TSV |
203 | goto error; |
204 | } | |
205 | ep->event = event; | |
206 | ep->event_name = kstrdup(event_name, GFP_KERNEL); | |
207 | if (!ep->event_name) | |
208 | goto error; | |
209 | ep->event_system = kstrdup(sys_name, GFP_KERNEL); | |
210 | if (!ep->event_system) | |
211 | goto error; | |
212 | ||
213 | ret = trace_probe_init(&ep->tp, this_event, group, false); | |
214 | if (ret < 0) | |
215 | goto error; | |
216 | ||
217 | dyn_event_init(&ep->devent, &eprobe_dyn_event_ops); | |
218 | return ep; | |
219 | error: | |
220 | trace_event_probe_cleanup(ep); | |
221 | return ERR_PTR(ret); | |
222 | } | |
223 | ||
224 | static int trace_eprobe_tp_arg_update(struct trace_eprobe *ep, int i) | |
225 | { | |
226 | struct probe_arg *parg = &ep->tp.args[i]; | |
227 | struct ftrace_event_field *field; | |
228 | struct list_head *head; | |
229 | ||
230 | head = trace_get_fields(ep->event); | |
231 | list_for_each_entry(field, head, link) { | |
232 | if (!strcmp(parg->code->data, field->name)) { | |
233 | kfree(parg->code->data); | |
234 | parg->code->data = field; | |
235 | return 0; | |
236 | } | |
237 | } | |
238 | kfree(parg->code->data); | |
239 | parg->code->data = NULL; | |
240 | return -ENOENT; | |
241 | } | |
242 | ||
243 | static int eprobe_event_define_fields(struct trace_event_call *event_call) | |
244 | { | |
245 | int ret; | |
246 | struct eprobe_trace_entry_head field; | |
247 | struct trace_probe *tp; | |
248 | ||
249 | tp = trace_probe_primary_from_call(event_call); | |
250 | if (WARN_ON_ONCE(!tp)) | |
251 | return -ENOENT; | |
252 | ||
253 | DEFINE_FIELD(unsigned int, type, FIELD_STRING_TYPE, 0); | |
254 | ||
255 | return traceprobe_define_arg_fields(event_call, sizeof(field), tp); | |
256 | } | |
257 | ||
258 | static struct trace_event_fields eprobe_fields_array[] = { | |
259 | { .type = TRACE_FUNCTION_TYPE, | |
260 | .define_fields = eprobe_event_define_fields }, | |
261 | {} | |
262 | }; | |
263 | ||
264 | /* Event entry printers */ | |
265 | static enum print_line_t | |
266 | print_eprobe_event(struct trace_iterator *iter, int flags, | |
267 | struct trace_event *event) | |
268 | { | |
269 | struct eprobe_trace_entry_head *field; | |
270 | struct trace_event_call *pevent; | |
271 | struct trace_event *probed_event; | |
272 | struct trace_seq *s = &iter->seq; | |
273 | struct trace_probe *tp; | |
274 | ||
275 | field = (struct eprobe_trace_entry_head *)iter->ent; | |
276 | tp = trace_probe_primary_from_call( | |
277 | container_of(event, struct trace_event_call, event)); | |
278 | if (WARN_ON_ONCE(!tp)) | |
279 | goto out; | |
280 | ||
281 | trace_seq_printf(s, "%s: (", trace_probe_name(tp)); | |
282 | ||
283 | probed_event = ftrace_find_event(field->type); | |
284 | if (probed_event) { | |
285 | pevent = container_of(probed_event, struct trace_event_call, event); | |
286 | trace_seq_printf(s, "%s.%s", pevent->class->system, | |
287 | trace_event_name(pevent)); | |
288 | } else { | |
289 | trace_seq_printf(s, "%u", field->type); | |
290 | } | |
291 | ||
292 | trace_seq_putc(s, ')'); | |
293 | ||
294 | if (print_probe_args(s, tp->args, tp->nr_args, | |
295 | (u8 *)&field[1], field) < 0) | |
296 | goto out; | |
297 | ||
298 | trace_seq_putc(s, '\n'); | |
299 | out: | |
300 | return trace_handle_return(s); | |
301 | } | |
302 | ||
303 | static unsigned long get_event_field(struct fetch_insn *code, void *rec) | |
304 | { | |
305 | struct ftrace_event_field *field = code->data; | |
306 | unsigned long val; | |
307 | void *addr; | |
308 | ||
309 | addr = rec + field->offset; | |
310 | ||
311 | switch (field->size) { | |
312 | case 1: | |
313 | if (field->is_signed) | |
314 | val = *(char *)addr; | |
315 | else | |
316 | val = *(unsigned char *)addr; | |
317 | break; | |
318 | case 2: | |
319 | if (field->is_signed) | |
320 | val = *(short *)addr; | |
321 | else | |
322 | val = *(unsigned short *)addr; | |
323 | break; | |
324 | case 4: | |
325 | if (field->is_signed) | |
326 | val = *(int *)addr; | |
327 | else | |
328 | val = *(unsigned int *)addr; | |
329 | break; | |
330 | default: | |
331 | if (field->is_signed) | |
332 | val = *(long *)addr; | |
333 | else | |
334 | val = *(unsigned long *)addr; | |
335 | break; | |
336 | } | |
337 | return val; | |
338 | } | |
339 | ||
340 | static int get_eprobe_size(struct trace_probe *tp, void *rec) | |
341 | { | |
342 | struct probe_arg *arg; | |
343 | int i, len, ret = 0; | |
344 | ||
345 | for (i = 0; i < tp->nr_args; i++) { | |
346 | arg = tp->args + i; | |
347 | if (unlikely(arg->dynamic)) { | |
348 | unsigned long val; | |
349 | ||
350 | val = get_event_field(arg->code, rec); | |
351 | len = process_fetch_insn_bottom(arg->code + 1, val, NULL, NULL); | |
352 | if (len > 0) | |
353 | ret += len; | |
354 | } | |
355 | } | |
356 | ||
357 | return ret; | |
358 | } | |
359 | ||
360 | /* Kprobe specific fetch functions */ | |
361 | ||
362 | /* Note that we don't verify it, since the code does not come from user space */ | |
363 | static int | |
364 | process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, | |
365 | void *base) | |
366 | { | |
367 | unsigned long val; | |
368 | ||
369 | val = get_event_field(code, rec); | |
370 | return process_fetch_insn_bottom(code + 1, val, dest, base); | |
371 | } | |
372 | NOKPROBE_SYMBOL(process_fetch_insn) | |
373 | ||
374 | /* Return the length of string -- including null terminal byte */ | |
375 | static nokprobe_inline int | |
376 | fetch_store_strlen_user(unsigned long addr) | |
377 | { | |
378 | const void __user *uaddr = (__force const void __user *)addr; | |
379 | ||
380 | return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); | |
381 | } | |
382 | ||
383 | /* Return the length of string -- including null terminal byte */ | |
384 | static nokprobe_inline int | |
385 | fetch_store_strlen(unsigned long addr) | |
386 | { | |
387 | int ret, len = 0; | |
388 | u8 c; | |
389 | ||
390 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE | |
391 | if (addr < TASK_SIZE) | |
392 | return fetch_store_strlen_user(addr); | |
393 | #endif | |
394 | ||
395 | do { | |
396 | ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); | |
397 | len++; | |
398 | } while (c && ret == 0 && len < MAX_STRING_SIZE); | |
399 | ||
400 | return (ret < 0) ? ret : len; | |
401 | } | |
402 | ||
403 | /* | |
404 | * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf | |
405 | * with max length and relative data location. | |
406 | */ | |
407 | static nokprobe_inline int | |
408 | fetch_store_string_user(unsigned long addr, void *dest, void *base) | |
409 | { | |
410 | const void __user *uaddr = (__force const void __user *)addr; | |
411 | int maxlen = get_loc_len(*(u32 *)dest); | |
412 | void *__dest; | |
413 | long ret; | |
414 | ||
415 | if (unlikely(!maxlen)) | |
416 | return -ENOMEM; | |
417 | ||
418 | __dest = get_loc_data(dest, base); | |
419 | ||
420 | ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); | |
421 | if (ret >= 0) | |
422 | *(u32 *)dest = make_data_loc(ret, __dest - base); | |
423 | ||
424 | return ret; | |
425 | } | |
426 | ||
427 | /* | |
428 | * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max | |
429 | * length and relative data location. | |
430 | */ | |
431 | static nokprobe_inline int | |
432 | fetch_store_string(unsigned long addr, void *dest, void *base) | |
433 | { | |
434 | int maxlen = get_loc_len(*(u32 *)dest); | |
435 | void *__dest; | |
436 | long ret; | |
437 | ||
438 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE | |
439 | if ((unsigned long)addr < TASK_SIZE) | |
440 | return fetch_store_string_user(addr, dest, base); | |
441 | #endif | |
442 | ||
443 | if (unlikely(!maxlen)) | |
444 | return -ENOMEM; | |
445 | ||
446 | __dest = get_loc_data(dest, base); | |
447 | ||
448 | /* | |
449 | * Try to get string again, since the string can be changed while | |
450 | * probing. | |
451 | */ | |
452 | ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); | |
453 | if (ret >= 0) | |
454 | *(u32 *)dest = make_data_loc(ret, __dest - base); | |
455 | ||
456 | return ret; | |
457 | } | |
458 | ||
459 | static nokprobe_inline int | |
460 | probe_mem_read_user(void *dest, void *src, size_t size) | |
461 | { | |
462 | const void __user *uaddr = (__force const void __user *)src; | |
463 | ||
464 | return copy_from_user_nofault(dest, uaddr, size); | |
465 | } | |
466 | ||
467 | static nokprobe_inline int | |
468 | probe_mem_read(void *dest, void *src, size_t size) | |
469 | { | |
470 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE | |
471 | if ((unsigned long)src < TASK_SIZE) | |
472 | return probe_mem_read_user(dest, src, size); | |
473 | #endif | |
474 | return copy_from_kernel_nofault(dest, src, size); | |
475 | } | |
476 | ||
477 | /* eprobe handler */ | |
478 | static inline void | |
479 | __eprobe_trace_func(struct eprobe_data *edata, void *rec) | |
480 | { | |
481 | struct eprobe_trace_entry_head *entry; | |
482 | struct trace_event_call *call = trace_probe_event_call(&edata->ep->tp); | |
483 | struct trace_event_buffer fbuffer; | |
484 | int dsize; | |
485 | ||
486 | if (WARN_ON_ONCE(call != edata->file->event_call)) | |
487 | return; | |
488 | ||
489 | if (trace_trigger_soft_disabled(edata->file)) | |
490 | return; | |
491 | ||
7491e2c4 | 492 | dsize = get_eprobe_size(&edata->ep->tp, rec); |
3e8b1a29 SRV |
493 | |
494 | entry = trace_event_buffer_reserve(&fbuffer, edata->file, | |
495 | sizeof(*entry) + edata->ep->tp.size + dsize); | |
496 | ||
497 | if (!entry) | |
7491e2c4 TSV |
498 | return; |
499 | ||
500 | entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); | |
501 | if (edata->ep->event) | |
502 | entry->type = edata->ep->event->event.type; | |
503 | else | |
504 | entry->type = 0; | |
505 | store_trace_args(&entry[1], &edata->ep->tp, rec, sizeof(*entry), dsize); | |
506 | ||
507 | trace_event_buffer_commit(&fbuffer); | |
508 | } | |
509 | ||
510 | /* | |
511 | * The event probe implementation uses event triggers to get access to | |
512 | * the event it is attached to, but is not an actual trigger. The below | |
513 | * functions are just stubs to fulfill what is needed to use the trigger | |
514 | * infrastructure. | |
515 | */ | |
516 | static int eprobe_trigger_init(struct event_trigger_ops *ops, | |
517 | struct event_trigger_data *data) | |
518 | { | |
519 | return 0; | |
520 | } | |
521 | ||
522 | static void eprobe_trigger_free(struct event_trigger_ops *ops, | |
523 | struct event_trigger_data *data) | |
524 | { | |
525 | ||
526 | } | |
527 | ||
528 | static int eprobe_trigger_print(struct seq_file *m, | |
529 | struct event_trigger_ops *ops, | |
530 | struct event_trigger_data *data) | |
531 | { | |
532 | /* Do not print eprobe event triggers */ | |
533 | return 0; | |
534 | } | |
535 | ||
536 | static void eprobe_trigger_func(struct event_trigger_data *data, | |
537 | struct trace_buffer *buffer, void *rec, | |
538 | struct ring_buffer_event *rbe) | |
539 | { | |
540 | struct eprobe_data *edata = data->private_data; | |
541 | ||
542 | __eprobe_trace_func(edata, rec); | |
543 | } | |
544 | ||
545 | static struct event_trigger_ops eprobe_trigger_ops = { | |
fb339e53 | 546 | .trigger = eprobe_trigger_func, |
7491e2c4 TSV |
547 | .print = eprobe_trigger_print, |
548 | .init = eprobe_trigger_init, | |
549 | .free = eprobe_trigger_free, | |
550 | }; | |
551 | ||
9ec5a7d1 TZ |
552 | static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops, |
553 | struct trace_event_file *file, | |
554 | char *glob, char *cmd, char *param) | |
7491e2c4 TSV |
555 | { |
556 | return -1; | |
557 | } | |
558 | ||
2378a2d6 TZ |
559 | static int eprobe_trigger_reg_func(char *glob, |
560 | struct event_trigger_data *data, | |
561 | struct trace_event_file *file) | |
7491e2c4 TSV |
562 | { |
563 | return -1; | |
564 | } | |
565 | ||
2378a2d6 TZ |
566 | static void eprobe_trigger_unreg_func(char *glob, |
567 | struct event_trigger_data *data, | |
568 | struct trace_event_file *file) | |
7491e2c4 TSV |
569 | { |
570 | ||
571 | } | |
572 | ||
573 | static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd, | |
574 | char *param) | |
575 | { | |
576 | return &eprobe_trigger_ops; | |
577 | } | |
578 | ||
579 | static struct event_command event_trigger_cmd = { | |
580 | .name = "eprobe", | |
581 | .trigger_type = ETT_EVENT_EPROBE, | |
582 | .flags = EVENT_CMD_FL_NEEDS_REC, | |
9ec5a7d1 | 583 | .parse = eprobe_trigger_cmd_parse, |
7491e2c4 TSV |
584 | .reg = eprobe_trigger_reg_func, |
585 | .unreg = eprobe_trigger_unreg_func, | |
586 | .unreg_all = NULL, | |
587 | .get_trigger_ops = eprobe_trigger_get_ops, | |
588 | .set_filter = NULL, | |
589 | }; | |
590 | ||
591 | static struct event_trigger_data * | |
592 | new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file) | |
593 | { | |
594 | struct event_trigger_data *trigger; | |
595 | struct eprobe_data *edata; | |
596 | ||
597 | edata = kzalloc(sizeof(*edata), GFP_KERNEL); | |
598 | trigger = kzalloc(sizeof(*trigger), GFP_KERNEL); | |
599 | if (!trigger || !edata) { | |
600 | kfree(edata); | |
601 | kfree(trigger); | |
602 | return ERR_PTR(-ENOMEM); | |
603 | } | |
604 | ||
605 | trigger->flags = EVENT_TRIGGER_FL_PROBE; | |
606 | trigger->count = -1; | |
607 | trigger->ops = &eprobe_trigger_ops; | |
608 | ||
609 | /* | |
610 | * EVENT PROBE triggers are not registered as commands with | |
611 | * register_event_command(), as they are not controlled by the user | |
612 | * from the trigger file | |
613 | */ | |
614 | trigger->cmd_ops = &event_trigger_cmd; | |
615 | ||
616 | INIT_LIST_HEAD(&trigger->list); | |
617 | RCU_INIT_POINTER(trigger->filter, NULL); | |
618 | ||
619 | edata->file = file; | |
620 | edata->ep = ep; | |
621 | trigger->private_data = edata; | |
622 | ||
623 | return trigger; | |
624 | } | |
625 | ||
626 | static int enable_eprobe(struct trace_eprobe *ep, | |
627 | struct trace_event_file *eprobe_file) | |
628 | { | |
629 | struct event_trigger_data *trigger; | |
630 | struct trace_event_file *file; | |
631 | struct trace_array *tr = eprobe_file->tr; | |
632 | ||
633 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
634 | if (!file) | |
635 | return -ENOENT; | |
636 | trigger = new_eprobe_trigger(ep, eprobe_file); | |
637 | if (IS_ERR(trigger)) | |
638 | return PTR_ERR(trigger); | |
639 | ||
640 | list_add_tail_rcu(&trigger->list, &file->triggers); | |
641 | ||
642 | trace_event_trigger_enable_disable(file, 1); | |
643 | update_cond_flag(file); | |
644 | ||
645 | return 0; | |
646 | } | |
647 | ||
648 | static struct trace_event_functions eprobe_funcs = { | |
649 | .trace = print_eprobe_event | |
650 | }; | |
651 | ||
652 | static int disable_eprobe(struct trace_eprobe *ep, | |
653 | struct trace_array *tr) | |
654 | { | |
655 | struct event_trigger_data *trigger; | |
656 | struct trace_event_file *file; | |
657 | struct eprobe_data *edata; | |
658 | ||
659 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
660 | if (!file) | |
661 | return -ENOENT; | |
662 | ||
663 | list_for_each_entry(trigger, &file->triggers, list) { | |
664 | if (!(trigger->flags & EVENT_TRIGGER_FL_PROBE)) | |
665 | continue; | |
666 | edata = trigger->private_data; | |
667 | if (edata->ep == ep) | |
668 | break; | |
669 | } | |
670 | if (list_entry_is_head(trigger, &file->triggers, list)) | |
671 | return -ENODEV; | |
672 | ||
673 | list_del_rcu(&trigger->list); | |
674 | ||
675 | trace_event_trigger_enable_disable(file, 0); | |
676 | update_cond_flag(file); | |
6675880f VS |
677 | |
678 | /* Make sure nothing is using the edata or trigger */ | |
679 | tracepoint_synchronize_unregister(); | |
680 | ||
681 | kfree(edata); | |
682 | kfree(trigger); | |
683 | ||
7491e2c4 TSV |
684 | return 0; |
685 | } | |
686 | ||
687 | static int enable_trace_eprobe(struct trace_event_call *call, | |
688 | struct trace_event_file *file) | |
689 | { | |
690 | struct trace_probe *pos, *tp; | |
691 | struct trace_eprobe *ep; | |
692 | bool enabled; | |
693 | int ret = 0; | |
694 | ||
695 | tp = trace_probe_primary_from_call(call); | |
696 | if (WARN_ON_ONCE(!tp)) | |
697 | return -ENODEV; | |
698 | enabled = trace_probe_is_enabled(tp); | |
699 | ||
700 | /* This also changes "enabled" state */ | |
701 | if (file) { | |
702 | ret = trace_probe_add_file(tp, file); | |
703 | if (ret) | |
704 | return ret; | |
705 | } else | |
706 | trace_probe_set_flag(tp, TP_FLAG_PROFILE); | |
707 | ||
708 | if (enabled) | |
709 | return 0; | |
710 | ||
711 | list_for_each_entry(pos, trace_probe_probe_list(tp), list) { | |
712 | ep = container_of(pos, struct trace_eprobe, tp); | |
713 | ret = enable_eprobe(ep, file); | |
714 | if (ret) | |
715 | break; | |
716 | enabled = true; | |
717 | } | |
718 | ||
719 | if (ret) { | |
720 | /* Failed to enable one of them. Roll back all */ | |
721 | if (enabled) | |
722 | disable_eprobe(ep, file->tr); | |
723 | if (file) | |
724 | trace_probe_remove_file(tp, file); | |
725 | else | |
726 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
727 | } | |
728 | ||
729 | return ret; | |
730 | } | |
731 | ||
732 | static int disable_trace_eprobe(struct trace_event_call *call, | |
733 | struct trace_event_file *file) | |
734 | { | |
735 | struct trace_probe *pos, *tp; | |
736 | struct trace_eprobe *ep; | |
737 | ||
738 | tp = trace_probe_primary_from_call(call); | |
739 | if (WARN_ON_ONCE(!tp)) | |
740 | return -ENODEV; | |
741 | ||
742 | if (file) { | |
743 | if (!trace_probe_get_file_link(tp, file)) | |
744 | return -ENOENT; | |
745 | if (!trace_probe_has_single_file(tp)) | |
746 | goto out; | |
747 | trace_probe_clear_flag(tp, TP_FLAG_TRACE); | |
748 | } else | |
749 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
750 | ||
751 | if (!trace_probe_is_enabled(tp)) { | |
752 | list_for_each_entry(pos, trace_probe_probe_list(tp), list) { | |
753 | ep = container_of(pos, struct trace_eprobe, tp); | |
754 | disable_eprobe(ep, file->tr); | |
755 | } | |
756 | } | |
757 | ||
758 | out: | |
759 | if (file) | |
760 | /* | |
761 | * Synchronization is done in below function. For perf event, | |
762 | * file == NULL and perf_trace_event_unreg() calls | |
763 | * tracepoint_synchronize_unregister() to ensure synchronize | |
764 | * event. We don't need to care about it. | |
765 | */ | |
766 | trace_probe_remove_file(tp, file); | |
767 | ||
768 | return 0; | |
769 | } | |
770 | ||
771 | static int eprobe_register(struct trace_event_call *event, | |
772 | enum trace_reg type, void *data) | |
773 | { | |
774 | struct trace_event_file *file = data; | |
775 | ||
776 | switch (type) { | |
777 | case TRACE_REG_REGISTER: | |
778 | return enable_trace_eprobe(event, file); | |
779 | case TRACE_REG_UNREGISTER: | |
780 | return disable_trace_eprobe(event, file); | |
781 | #ifdef CONFIG_PERF_EVENTS | |
782 | case TRACE_REG_PERF_REGISTER: | |
783 | case TRACE_REG_PERF_UNREGISTER: | |
784 | case TRACE_REG_PERF_OPEN: | |
785 | case TRACE_REG_PERF_CLOSE: | |
786 | case TRACE_REG_PERF_ADD: | |
787 | case TRACE_REG_PERF_DEL: | |
788 | return 0; | |
789 | #endif | |
790 | } | |
791 | return 0; | |
792 | } | |
793 | ||
794 | static inline void init_trace_eprobe_call(struct trace_eprobe *ep) | |
795 | { | |
796 | struct trace_event_call *call = trace_probe_event_call(&ep->tp); | |
797 | ||
798 | call->flags = TRACE_EVENT_FL_EPROBE; | |
799 | call->event.funcs = &eprobe_funcs; | |
800 | call->class->fields_array = eprobe_fields_array; | |
801 | call->class->reg = eprobe_register; | |
802 | } | |
803 | ||
804 | static struct trace_event_call * | |
805 | find_and_get_event(const char *system, const char *event_name) | |
806 | { | |
807 | struct trace_event_call *tp_event; | |
808 | const char *name; | |
809 | ||
810 | list_for_each_entry(tp_event, &ftrace_events, list) { | |
811 | /* Skip other probes and ftrace events */ | |
812 | if (tp_event->flags & | |
813 | (TRACE_EVENT_FL_IGNORE_ENABLE | | |
814 | TRACE_EVENT_FL_KPROBE | | |
815 | TRACE_EVENT_FL_UPROBE | | |
816 | TRACE_EVENT_FL_EPROBE)) | |
817 | continue; | |
818 | if (!tp_event->class->system || | |
819 | strcmp(system, tp_event->class->system)) | |
820 | continue; | |
821 | name = trace_event_name(tp_event); | |
822 | if (!name || strcmp(event_name, name)) | |
823 | continue; | |
824 | if (!trace_event_try_get_ref(tp_event)) { | |
825 | return NULL; | |
826 | break; | |
827 | } | |
828 | return tp_event; | |
829 | break; | |
830 | } | |
831 | return NULL; | |
832 | } | |
833 | ||
834 | static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i) | |
835 | { | |
836 | unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT; | |
837 | int ret; | |
838 | ||
839 | ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags); | |
840 | if (ret) | |
841 | return ret; | |
842 | ||
843 | if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) | |
844 | ret = trace_eprobe_tp_arg_update(ep, i); | |
845 | ||
846 | return ret; | |
847 | } | |
848 | ||
849 | static int __trace_eprobe_create(int argc, const char *argv[]) | |
850 | { | |
851 | /* | |
852 | * Argument syntax: | |
853 | * e[:[GRP/]ENAME] SYSTEM.EVENT [FETCHARGS] | |
854 | * Fetch args: | |
855 | * <name>=$<field>[:TYPE] | |
856 | */ | |
857 | const char *event = NULL, *group = EPROBE_EVENT_SYSTEM; | |
858 | const char *sys_event = NULL, *sys_name = NULL; | |
859 | struct trace_event_call *event_call; | |
860 | struct trace_eprobe *ep = NULL; | |
861 | char buf1[MAX_EVENT_NAME_LEN]; | |
862 | char buf2[MAX_EVENT_NAME_LEN]; | |
863 | int ret = 0; | |
864 | int i; | |
865 | ||
866 | if (argc < 2 || argv[0][0] != 'e') | |
867 | return -ECANCELED; | |
868 | ||
869 | trace_probe_log_init("event_probe", argc, argv); | |
870 | ||
871 | event = strchr(&argv[0][1], ':'); | |
872 | if (event) { | |
873 | event++; | |
874 | ret = traceprobe_parse_event_name(&event, &group, buf1, | |
875 | event - argv[0]); | |
876 | if (ret) | |
877 | goto parse_error; | |
878 | } else { | |
879 | strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN); | |
880 | sanitize_event_name(buf1); | |
881 | event = buf1; | |
882 | } | |
883 | if (!is_good_name(event) || !is_good_name(group)) | |
884 | goto parse_error; | |
885 | ||
886 | sys_event = argv[1]; | |
887 | ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, | |
888 | sys_event - argv[1]); | |
889 | if (ret || !sys_name) | |
890 | goto parse_error; | |
891 | if (!is_good_name(sys_event) || !is_good_name(sys_name)) | |
892 | goto parse_error; | |
893 | ||
894 | mutex_lock(&event_mutex); | |
895 | event_call = find_and_get_event(sys_name, sys_event); | |
896 | ep = alloc_event_probe(group, event, event_call, argc - 2); | |
897 | mutex_unlock(&event_mutex); | |
898 | ||
899 | if (IS_ERR(ep)) { | |
900 | ret = PTR_ERR(ep); | |
ddcf906f | 901 | /* This must return -ENOMEM or missing event, else there is a bug */ |
7fa598f9 | 902 | WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV); |
5615e088 DC |
903 | ep = NULL; |
904 | goto error; | |
7491e2c4 TSV |
905 | } |
906 | ||
907 | argc -= 2; argv += 2; | |
908 | /* parse arguments */ | |
909 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
910 | trace_probe_log_set_index(i + 2); | |
911 | ret = trace_eprobe_tp_update_arg(ep, argv, i); | |
912 | if (ret) | |
913 | goto error; | |
914 | } | |
915 | ret = traceprobe_set_print_fmt(&ep->tp, PROBE_PRINT_EVENT); | |
916 | if (ret < 0) | |
917 | goto error; | |
918 | init_trace_eprobe_call(ep); | |
919 | mutex_lock(&event_mutex); | |
920 | ret = trace_probe_register_event_call(&ep->tp); | |
921 | if (ret) { | |
922 | if (ret == -EEXIST) { | |
923 | trace_probe_log_set_index(0); | |
924 | trace_probe_log_err(0, EVENT_EXIST); | |
925 | } | |
926 | mutex_unlock(&event_mutex); | |
927 | goto error; | |
928 | } | |
929 | ret = dyn_event_add(&ep->devent, &ep->tp.event->call); | |
930 | mutex_unlock(&event_mutex); | |
931 | return ret; | |
932 | parse_error: | |
933 | ret = -EINVAL; | |
934 | error: | |
935 | trace_event_probe_cleanup(ep); | |
936 | return ret; | |
937 | } | |
938 | ||
939 | /* | |
940 | * Register dynevent at core_initcall. This allows kernel to setup eprobe | |
941 | * events in postcore_initcall without tracefs. | |
942 | */ | |
943 | static __init int trace_events_eprobe_init_early(void) | |
944 | { | |
945 | int err = 0; | |
946 | ||
947 | err = dyn_event_register(&eprobe_dyn_event_ops); | |
948 | if (err) | |
949 | pr_warn("Could not register eprobe_dyn_event_ops\n"); | |
950 | ||
951 | return err; | |
952 | } | |
953 | core_initcall(trace_events_eprobe_init_early); |