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21f58fb7 FD |
1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
2 | * | |
3 | * lttng-event-notifier-notification.c | |
4 | * | |
5 | * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com> | |
6 | */ | |
7 | ||
42f3ef8c FD |
8 | #include <linux/bug.h> |
9 | ||
10 | #include <lttng/lttng-bytecode.h> | |
21f58fb7 | 11 | #include <lttng/events.h> |
42f3ef8c | 12 | #include <lttng/msgpack.h> |
21f58fb7 | 13 | #include <lttng/event-notifier-notification.h> |
6657edec | 14 | #include <wrapper/barrier.h> |
21f58fb7 | 15 | |
99d223ad | 16 | /* |
e699ee6c MD |
17 | * The capture buffer size needs to be below 1024 bytes to avoid the |
18 | * frame to be larger than the 1024 limit enforced by the kernel. If we | |
19 | * ever need to increase it, we will need to use a memory allocation | |
20 | * scheme which allows allocating temporary memory chunks from the | |
21 | * instrumentation sites. This could be done by adapting lttng | |
22 | * tp-mempool to become nmi-safe and lock-free. | |
99d223ad FD |
23 | */ |
24 | #define CAPTURE_BUFFER_SIZE 512 | |
25 | ||
26 | struct lttng_event_notifier_notification { | |
27 | int notification_fd; | |
28 | uint64_t event_notifier_token; | |
29 | uint8_t capture_buf[CAPTURE_BUFFER_SIZE]; | |
30 | struct lttng_msgpack_writer writer; | |
31 | bool has_captures; | |
32 | }; | |
33 | ||
42f3ef8c FD |
34 | static |
35 | int capture_enum(struct lttng_msgpack_writer *writer, | |
36 | struct lttng_interpreter_output *output) | |
37 | { | |
38 | int ret; | |
39 | ||
40 | /* | |
41 | * Enums are captured as a map containing 2 key-value pairs. Such as: | |
42 | * - type: enum | |
43 | * value: 177 | |
44 | */ | |
45 | ret = lttng_msgpack_begin_map(writer, 2); | |
46 | if (ret) { | |
47 | WARN_ON_ONCE(1); | |
48 | goto end; | |
49 | } | |
50 | ||
51 | ret = lttng_msgpack_write_str(writer, "type"); | |
52 | if (ret) { | |
53 | WARN_ON_ONCE(1); | |
54 | goto end; | |
55 | } | |
56 | ||
57 | ret = lttng_msgpack_write_str(writer, "enum"); | |
58 | if (ret) { | |
59 | WARN_ON_ONCE(1); | |
60 | goto end; | |
61 | } | |
62 | ||
63 | ret = lttng_msgpack_write_str(writer, "value"); | |
64 | if (ret) { | |
65 | WARN_ON_ONCE(1); | |
66 | goto end; | |
67 | } | |
68 | ||
69 | switch (output->type) { | |
70 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
71 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); | |
72 | if (ret) { | |
73 | WARN_ON_ONCE(1); | |
74 | goto end; | |
75 | } | |
76 | break; | |
77 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
78 | ret = lttng_msgpack_write_signed_integer(writer, output->u.u); | |
79 | if (ret) { | |
80 | WARN_ON_ONCE(1); | |
81 | goto end; | |
82 | } | |
83 | break; | |
84 | default: | |
85 | WARN_ON(1); | |
86 | } | |
87 | ||
88 | ret = lttng_msgpack_end_map(writer); | |
89 | if (ret) | |
90 | WARN_ON_ONCE(1); | |
91 | ||
92 | end: | |
93 | return ret; | |
94 | } | |
95 | ||
96 | static | |
97 | int64_t capture_sequence_element_signed(uint8_t *ptr, | |
98 | const struct lttng_integer_type *type) | |
99 | { | |
100 | int64_t value = 0; | |
101 | unsigned int size = type->size; | |
102 | bool byte_order_reversed = type->reverse_byte_order; | |
103 | ||
104 | switch (size) { | |
105 | case 8: | |
106 | value = *ptr; | |
107 | break; | |
108 | case 16: | |
109 | { | |
110 | int16_t tmp; | |
111 | tmp = *(int16_t *) ptr; | |
112 | if (byte_order_reversed) | |
113 | __swab16s(&tmp); | |
114 | ||
115 | value = tmp; | |
116 | break; | |
117 | } | |
118 | case 32: | |
119 | { | |
120 | int32_t tmp; | |
121 | tmp = *(int32_t *) ptr; | |
122 | if (byte_order_reversed) | |
123 | __swab32s(&tmp); | |
124 | ||
125 | value = tmp; | |
126 | break; | |
127 | } | |
128 | case 64: | |
129 | { | |
130 | int64_t tmp; | |
131 | tmp = *(int64_t *) ptr; | |
132 | if (byte_order_reversed) | |
133 | __swab64s(&tmp); | |
134 | ||
135 | value = tmp; | |
136 | break; | |
137 | } | |
138 | default: | |
139 | WARN_ON(1); | |
140 | } | |
141 | ||
142 | return value; | |
143 | } | |
144 | ||
145 | static | |
146 | uint64_t capture_sequence_element_unsigned(uint8_t *ptr, | |
147 | const struct lttng_integer_type *type) | |
148 | { | |
149 | uint64_t value = 0; | |
150 | unsigned int size = type->size; | |
151 | bool byte_order_reversed = type->reverse_byte_order; | |
152 | ||
153 | switch (size) { | |
154 | case 8: | |
155 | value = *ptr; | |
156 | break; | |
157 | case 16: | |
158 | { | |
159 | uint16_t tmp; | |
160 | tmp = *(uint16_t *) ptr; | |
161 | if (byte_order_reversed) | |
162 | __swab16s(&tmp); | |
163 | ||
164 | value = tmp; | |
165 | break; | |
166 | } | |
167 | case 32: | |
168 | { | |
169 | uint32_t tmp; | |
170 | tmp = *(uint32_t *) ptr; | |
171 | if (byte_order_reversed) | |
172 | __swab32s(&tmp); | |
173 | ||
174 | value = tmp; | |
175 | break; | |
176 | } | |
177 | case 64: | |
178 | { | |
179 | uint64_t tmp; | |
180 | tmp = *(uint64_t *) ptr; | |
181 | if (byte_order_reversed) | |
182 | __swab64s(&tmp); | |
183 | ||
184 | value = tmp; | |
185 | break; | |
186 | } | |
187 | default: | |
188 | WARN_ON(1); | |
189 | } | |
190 | ||
191 | return value; | |
192 | } | |
193 | ||
42f3ef8c FD |
194 | int capture_sequence(struct lttng_msgpack_writer *writer, |
195 | struct lttng_interpreter_output *output) | |
196 | { | |
197 | const struct lttng_integer_type *integer_type = NULL; | |
198 | const struct lttng_type *nested_type; | |
199 | uint8_t *ptr; | |
200 | bool signedness; | |
201 | int ret, i; | |
202 | ||
203 | ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem); | |
204 | if (ret) { | |
205 | WARN_ON_ONCE(1); | |
206 | goto end; | |
207 | } | |
208 | ||
209 | ptr = (uint8_t *) output->u.sequence.ptr; | |
210 | nested_type = output->u.sequence.nested_type; | |
12bb2edb MD |
211 | switch (nested_type->type) { |
212 | case lttng_kernel_type_integer: | |
42f3ef8c FD |
213 | integer_type = &nested_type->u.integer; |
214 | break; | |
12bb2edb | 215 | case lttng_kernel_type_enum_nestable: |
42f3ef8c FD |
216 | /* Treat enumeration as an integer. */ |
217 | integer_type = &nested_type->u.enum_nestable.container_type->u.integer; | |
218 | break; | |
219 | default: | |
220 | /* Capture of array of non-integer are not supported. */ | |
221 | WARN_ON(1); | |
222 | } | |
223 | signedness = integer_type->signedness; | |
224 | for (i = 0; i < output->u.sequence.nr_elem; i++) { | |
225 | if (signedness) { | |
226 | ret = lttng_msgpack_write_signed_integer(writer, | |
227 | capture_sequence_element_signed(ptr, integer_type)); | |
228 | if (ret) { | |
229 | WARN_ON_ONCE(1); | |
230 | goto end; | |
231 | } | |
232 | } else { | |
233 | ret = lttng_msgpack_write_unsigned_integer(writer, | |
234 | capture_sequence_element_unsigned(ptr, integer_type)); | |
235 | if (ret) { | |
236 | WARN_ON_ONCE(1); | |
237 | goto end; | |
238 | } | |
239 | } | |
240 | ||
241 | /* | |
242 | * We assume that alignment is smaller or equal to the size. | |
243 | * This currently holds true but if it changes in the future, | |
244 | * we will want to change the pointer arithmetics below to | |
245 | * take into account that the next element might be further | |
246 | * away. | |
247 | */ | |
248 | WARN_ON(integer_type->alignment > integer_type->size); | |
249 | ||
250 | /* Size is in number of bits. */ | |
251 | ptr += (integer_type->size / CHAR_BIT) ; | |
252 | } | |
253 | ||
254 | ret = lttng_msgpack_end_array(writer); | |
255 | if (ret) | |
256 | WARN_ON_ONCE(1); | |
257 | end: | |
258 | return ret; | |
259 | } | |
260 | ||
99d223ad FD |
261 | static |
262 | int notification_append_capture( | |
263 | struct lttng_event_notifier_notification *notif, | |
264 | struct lttng_interpreter_output *output) | |
265 | { | |
266 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
267 | int ret = 0; | |
268 | ||
269 | switch (output->type) { | |
270 | case LTTNG_INTERPRETER_TYPE_S64: | |
271 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); | |
272 | if (ret) { | |
273 | WARN_ON_ONCE(1); | |
274 | goto end; | |
275 | } | |
276 | break; | |
277 | case LTTNG_INTERPRETER_TYPE_U64: | |
278 | ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u); | |
279 | if (ret) { | |
280 | WARN_ON_ONCE(1); | |
281 | goto end; | |
282 | } | |
283 | break; | |
284 | case LTTNG_INTERPRETER_TYPE_STRING: | |
285 | ret = lttng_msgpack_write_str(writer, output->u.str.str); | |
286 | if (ret) { | |
287 | WARN_ON_ONCE(1); | |
288 | goto end; | |
289 | } | |
290 | break; | |
291 | case LTTNG_INTERPRETER_TYPE_SEQUENCE: | |
292 | ret = capture_sequence(writer, output); | |
293 | if (ret) { | |
294 | WARN_ON_ONCE(1); | |
295 | goto end; | |
296 | } | |
297 | break; | |
298 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
299 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
300 | ret = capture_enum(writer, output); | |
301 | if (ret) { | |
302 | WARN_ON_ONCE(1); | |
303 | goto end; | |
304 | } | |
305 | break; | |
306 | default: | |
307 | ret = -1; | |
308 | WARN_ON(1); | |
309 | } | |
310 | end: | |
311 | return ret; | |
312 | } | |
313 | ||
314 | static | |
315 | int notification_append_empty_capture( | |
316 | struct lttng_event_notifier_notification *notif) | |
317 | { | |
318 | int ret = lttng_msgpack_write_nil(¬if->writer); | |
319 | if (ret) | |
320 | WARN_ON_ONCE(1); | |
321 | ||
322 | return ret; | |
323 | } | |
324 | ||
325 | static | |
326 | int notification_init(struct lttng_event_notifier_notification *notif, | |
327 | struct lttng_event_notifier *event_notifier) | |
328 | { | |
329 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
330 | int ret = 0; | |
331 | ||
332 | notif->has_captures = false; | |
333 | ||
334 | if (event_notifier->num_captures > 0) { | |
335 | lttng_msgpack_writer_init(writer, notif->capture_buf, | |
336 | CAPTURE_BUFFER_SIZE); | |
337 | ||
338 | ret = lttng_msgpack_begin_array(writer, event_notifier->num_captures); | |
339 | if (ret) { | |
340 | WARN_ON_ONCE(1); | |
341 | goto end; | |
342 | } | |
343 | ||
344 | notif->has_captures = true; | |
345 | } | |
346 | ||
347 | end: | |
348 | return ret; | |
349 | } | |
350 | ||
99f52fcc FD |
351 | static |
352 | void record_error(struct lttng_event_notifier *event_notifier) | |
353 | { | |
354 | ||
355 | struct lttng_event_notifier_group *event_notifier_group = event_notifier->group; | |
ab04d7b1 | 356 | struct lttng_counter *error_counter; |
99f52fcc FD |
357 | size_t dimension_index[1]; |
358 | int ret; | |
359 | ||
ab04d7b1 | 360 | /* |
6657edec | 361 | * lttng_smp_load_acquire paired with lttng_smp_store_release orders |
ab04d7b1 MD |
362 | * creation of the error counter and setting error_counter_len |
363 | * before the error_counter is used. | |
364 | */ | |
6657edec | 365 | error_counter = lttng_smp_load_acquire(&event_notifier_group->error_counter); |
a83d6831 | 366 | /* This group may not have an error counter attached to it. */ |
ab04d7b1 | 367 | if (!error_counter) |
a83d6831 FD |
368 | return; |
369 | ||
99f52fcc FD |
370 | dimension_index[0] = event_notifier->error_counter_index; |
371 | ||
ab04d7b1 | 372 | ret = error_counter->ops->counter_add(error_counter->counter, |
99f52fcc FD |
373 | dimension_index, 1); |
374 | if (ret) | |
375 | WARN_ON_ONCE(1); | |
376 | } | |
377 | ||
99d223ad FD |
378 | static |
379 | void notification_send(struct lttng_event_notifier_notification *notif, | |
380 | struct lttng_event_notifier *event_notifier) | |
21f58fb7 FD |
381 | { |
382 | struct lttng_event_notifier_group *event_notifier_group = event_notifier->group; | |
383 | struct lib_ring_buffer_ctx ctx; | |
99d223ad FD |
384 | struct lttng_kernel_event_notifier_notification kernel_notif; |
385 | size_t capture_buffer_content_len, reserve_size; | |
21f58fb7 FD |
386 | int ret; |
387 | ||
99d223ad FD |
388 | reserve_size = sizeof(kernel_notif); |
389 | kernel_notif.token = event_notifier->user_token; | |
21f58fb7 | 390 | |
99d223ad FD |
391 | if (notif->has_captures) { |
392 | capture_buffer_content_len = notif->writer.write_pos - notif->writer.buffer; | |
393 | } else { | |
394 | capture_buffer_content_len = 0; | |
395 | } | |
396 | ||
397 | WARN_ON_ONCE(capture_buffer_content_len > CAPTURE_BUFFER_SIZE); | |
398 | ||
399 | reserve_size += capture_buffer_content_len; | |
400 | kernel_notif.capture_buf_size = capture_buffer_content_len; | |
401 | ||
402 | lib_ring_buffer_ctx_init(&ctx, event_notifier_group->chan, NULL, reserve_size, | |
403 | lttng_alignof(kernel_notif), -1); | |
21f58fb7 FD |
404 | ret = event_notifier_group->ops->event_reserve(&ctx, 0); |
405 | if (ret < 0) { | |
99f52fcc | 406 | record_error(event_notifier); |
21f58fb7 FD |
407 | return; |
408 | } | |
99d223ad FD |
409 | |
410 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(kernel_notif)); | |
411 | ||
412 | /* Write the notif structure. */ | |
413 | event_notifier_group->ops->event_write(&ctx, &kernel_notif, | |
414 | sizeof(kernel_notif)); | |
415 | ||
416 | /* | |
417 | * Write the capture buffer. No need to realigned as the below is a raw | |
418 | * char* buffer. | |
419 | */ | |
420 | event_notifier_group->ops->event_write(&ctx, ¬if->capture_buf, | |
421 | capture_buffer_content_len); | |
422 | ||
21f58fb7 FD |
423 | event_notifier_group->ops->event_commit(&ctx); |
424 | irq_work_queue(&event_notifier_group->wakeup_pending); | |
425 | } | |
99d223ad FD |
426 | |
427 | void lttng_event_notifier_notification_send(struct lttng_event_notifier *event_notifier, | |
428 | struct lttng_probe_ctx *lttng_probe_ctx, | |
c3eddb2e MD |
429 | const char *stack_data, |
430 | struct lttng_kernel_notifier_ctx *notif_ctx) | |
99d223ad FD |
431 | { |
432 | struct lttng_event_notifier_notification notif = { 0 }; | |
433 | int ret; | |
434 | ||
435 | if (unlikely(!READ_ONCE(event_notifier->enabled))) | |
436 | return; | |
437 | ||
438 | ret = notification_init(¬if, event_notifier); | |
439 | if (ret) { | |
440 | WARN_ON_ONCE(1); | |
441 | goto end; | |
442 | } | |
443 | ||
c3eddb2e | 444 | if (unlikely(notif_ctx->eval_capture)) { |
99d223ad FD |
445 | struct lttng_bytecode_runtime *capture_bc_runtime; |
446 | ||
447 | /* | |
448 | * Iterate over all the capture bytecodes. If the interpreter | |
449 | * functions returns successfully, append the value of the | |
450 | * `output` parameter to the capture buffer. If the interpreter | |
451 | * fails, append an empty capture to the buffer. | |
452 | */ | |
c3eddb2e | 453 | list_for_each_entry_rcu(capture_bc_runtime, |
99d223ad FD |
454 | &event_notifier->capture_bytecode_runtime_head, node) { |
455 | struct lttng_interpreter_output output; | |
456 | ||
457 | if (capture_bc_runtime->interpreter_funcs.capture(capture_bc_runtime, | |
458 | lttng_probe_ctx, stack_data, &output) & LTTNG_INTERPRETER_RECORD_FLAG) | |
459 | ret = notification_append_capture(¬if, &output); | |
460 | else | |
461 | ret = notification_append_empty_capture(¬if); | |
462 | ||
463 | if (ret) | |
464 | printk(KERN_WARNING "Error appending capture to notification"); | |
465 | } | |
466 | } | |
467 | ||
468 | /* | |
469 | * Send the notification (including the capture buffer) to the | |
470 | * sessiond. | |
471 | */ | |
472 | notification_send(¬if, event_notifier); | |
473 | end: | |
474 | return; | |
475 | } |