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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> |
437d5aa5 | 14 | #include <lttng/events-internal.h> |
11b589f6 | 15 | #include <lttng/probe-user.h> |
6657edec | 16 | #include <wrapper/barrier.h> |
21f58fb7 | 17 | |
99d223ad | 18 | /* |
e699ee6c MD |
19 | * The capture buffer size needs to be below 1024 bytes to avoid the |
20 | * frame to be larger than the 1024 limit enforced by the kernel. If we | |
21 | * ever need to increase it, we will need to use a memory allocation | |
22 | * scheme which allows allocating temporary memory chunks from the | |
23 | * instrumentation sites. This could be done by adapting lttng | |
24 | * tp-mempool to become nmi-safe and lock-free. | |
99d223ad FD |
25 | */ |
26 | #define CAPTURE_BUFFER_SIZE 512 | |
27 | ||
28 | struct lttng_event_notifier_notification { | |
29 | int notification_fd; | |
30 | uint64_t event_notifier_token; | |
31 | uint8_t capture_buf[CAPTURE_BUFFER_SIZE]; | |
32 | struct lttng_msgpack_writer writer; | |
33 | bool has_captures; | |
34 | }; | |
35 | ||
42f3ef8c FD |
36 | static |
37 | int capture_enum(struct lttng_msgpack_writer *writer, | |
38 | struct lttng_interpreter_output *output) | |
39 | { | |
40 | int ret; | |
41 | ||
42 | /* | |
43 | * Enums are captured as a map containing 2 key-value pairs. Such as: | |
44 | * - type: enum | |
45 | * value: 177 | |
46 | */ | |
47 | ret = lttng_msgpack_begin_map(writer, 2); | |
48 | if (ret) { | |
42f3ef8c FD |
49 | goto end; |
50 | } | |
51 | ||
52 | ret = lttng_msgpack_write_str(writer, "type"); | |
53 | if (ret) { | |
42f3ef8c FD |
54 | goto end; |
55 | } | |
56 | ||
57 | ret = lttng_msgpack_write_str(writer, "enum"); | |
58 | if (ret) { | |
42f3ef8c FD |
59 | goto end; |
60 | } | |
61 | ||
62 | ret = lttng_msgpack_write_str(writer, "value"); | |
63 | if (ret) { | |
42f3ef8c FD |
64 | goto end; |
65 | } | |
66 | ||
67 | switch (output->type) { | |
68 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
69 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); | |
70 | if (ret) { | |
42f3ef8c FD |
71 | goto end; |
72 | } | |
73 | break; | |
74 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
75 | ret = lttng_msgpack_write_signed_integer(writer, output->u.u); | |
76 | if (ret) { | |
42f3ef8c FD |
77 | goto end; |
78 | } | |
79 | break; | |
80 | default: | |
736f2dd6 | 81 | WARN_ON_ONCE(1); |
42f3ef8c FD |
82 | } |
83 | ||
84 | ret = lttng_msgpack_end_map(writer); | |
42f3ef8c FD |
85 | end: |
86 | return ret; | |
87 | } | |
88 | ||
89 | static | |
90 | int64_t capture_sequence_element_signed(uint8_t *ptr, | |
437d5aa5 | 91 | const struct lttng_kernel_type_integer *type) |
42f3ef8c FD |
92 | { |
93 | int64_t value = 0; | |
94 | unsigned int size = type->size; | |
11b589f6 | 95 | bool user = type->user; |
42f3ef8c FD |
96 | bool byte_order_reversed = type->reverse_byte_order; |
97 | ||
98 | switch (size) { | |
99 | case 8: | |
11b589f6 MD |
100 | { |
101 | int8_t tmp; | |
102 | ||
103 | if (user) { | |
104 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int8_t))) | |
105 | tmp = 0; | |
106 | } else { | |
107 | tmp = *ptr; | |
108 | } | |
109 | value = tmp; | |
42f3ef8c | 110 | break; |
11b589f6 | 111 | } |
42f3ef8c FD |
112 | case 16: |
113 | { | |
114 | int16_t tmp; | |
11b589f6 MD |
115 | |
116 | if (user) { | |
117 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int16_t))) | |
118 | tmp = 0; | |
119 | } else { | |
120 | tmp = *(int16_t *) ptr; | |
121 | } | |
42f3ef8c FD |
122 | if (byte_order_reversed) |
123 | __swab16s(&tmp); | |
42f3ef8c FD |
124 | value = tmp; |
125 | break; | |
126 | } | |
127 | case 32: | |
128 | { | |
129 | int32_t tmp; | |
11b589f6 MD |
130 | |
131 | if (user) { | |
132 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int32_t))) | |
133 | tmp = 0; | |
134 | } else { | |
135 | tmp = *(int32_t *) ptr; | |
136 | } | |
42f3ef8c FD |
137 | if (byte_order_reversed) |
138 | __swab32s(&tmp); | |
42f3ef8c FD |
139 | value = tmp; |
140 | break; | |
141 | } | |
142 | case 64: | |
143 | { | |
144 | int64_t tmp; | |
11b589f6 MD |
145 | |
146 | if (user) { | |
147 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int64_t))) | |
148 | tmp = 0; | |
149 | } else { | |
150 | tmp = *(int64_t *) ptr; | |
151 | } | |
42f3ef8c FD |
152 | if (byte_order_reversed) |
153 | __swab64s(&tmp); | |
42f3ef8c FD |
154 | value = tmp; |
155 | break; | |
156 | } | |
157 | default: | |
736f2dd6 | 158 | WARN_ON_ONCE(1); |
42f3ef8c FD |
159 | } |
160 | ||
161 | return value; | |
162 | } | |
163 | ||
164 | static | |
165 | uint64_t capture_sequence_element_unsigned(uint8_t *ptr, | |
437d5aa5 | 166 | const struct lttng_kernel_type_integer *type) |
42f3ef8c FD |
167 | { |
168 | uint64_t value = 0; | |
169 | unsigned int size = type->size; | |
11b589f6 | 170 | bool user = type->user; |
42f3ef8c FD |
171 | bool byte_order_reversed = type->reverse_byte_order; |
172 | ||
173 | switch (size) { | |
174 | case 8: | |
11b589f6 MD |
175 | { |
176 | uint8_t tmp; | |
177 | ||
178 | if (user) { | |
179 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint8_t))) | |
180 | tmp = 0; | |
181 | } else { | |
182 | tmp = *ptr; | |
183 | } | |
184 | value = tmp; | |
42f3ef8c | 185 | break; |
11b589f6 | 186 | } |
42f3ef8c FD |
187 | case 16: |
188 | { | |
189 | uint16_t tmp; | |
11b589f6 MD |
190 | |
191 | if (user) { | |
192 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint16_t))) | |
193 | tmp = 0; | |
194 | } else { | |
195 | tmp = *(uint16_t *) ptr; | |
196 | } | |
42f3ef8c FD |
197 | if (byte_order_reversed) |
198 | __swab16s(&tmp); | |
42f3ef8c FD |
199 | value = tmp; |
200 | break; | |
201 | } | |
202 | case 32: | |
203 | { | |
204 | uint32_t tmp; | |
11b589f6 MD |
205 | |
206 | if (user) { | |
207 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint32_t))) | |
208 | tmp = 0; | |
209 | } else { | |
210 | tmp = *(uint32_t *) ptr; | |
211 | } | |
42f3ef8c FD |
212 | if (byte_order_reversed) |
213 | __swab32s(&tmp); | |
42f3ef8c FD |
214 | value = tmp; |
215 | break; | |
216 | } | |
217 | case 64: | |
218 | { | |
219 | uint64_t tmp; | |
11b589f6 MD |
220 | |
221 | if (user) { | |
222 | if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint64_t))) | |
223 | tmp = 0; | |
224 | } else { | |
225 | tmp = *(uint64_t *) ptr; | |
226 | } | |
42f3ef8c FD |
227 | if (byte_order_reversed) |
228 | __swab64s(&tmp); | |
42f3ef8c FD |
229 | value = tmp; |
230 | break; | |
231 | } | |
232 | default: | |
736f2dd6 | 233 | WARN_ON_ONCE(1); |
42f3ef8c FD |
234 | } |
235 | ||
236 | return value; | |
237 | } | |
238 | ||
42f3ef8c FD |
239 | int capture_sequence(struct lttng_msgpack_writer *writer, |
240 | struct lttng_interpreter_output *output) | |
241 | { | |
437d5aa5 MD |
242 | const struct lttng_kernel_type_integer *integer_type = NULL; |
243 | const struct lttng_kernel_type_common *nested_type; | |
42f3ef8c FD |
244 | uint8_t *ptr; |
245 | bool signedness; | |
246 | int ret, i; | |
247 | ||
248 | ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem); | |
249 | if (ret) { | |
42f3ef8c FD |
250 | goto end; |
251 | } | |
252 | ||
253 | ptr = (uint8_t *) output->u.sequence.ptr; | |
254 | nested_type = output->u.sequence.nested_type; | |
12bb2edb MD |
255 | switch (nested_type->type) { |
256 | case lttng_kernel_type_integer: | |
437d5aa5 | 257 | integer_type = lttng_kernel_get_type_integer(nested_type); |
42f3ef8c | 258 | break; |
437d5aa5 | 259 | case lttng_kernel_type_enum: |
42f3ef8c | 260 | /* Treat enumeration as an integer. */ |
437d5aa5 | 261 | integer_type = lttng_kernel_get_type_integer(lttng_kernel_get_type_enum(nested_type)->container_type); |
42f3ef8c FD |
262 | break; |
263 | default: | |
264 | /* Capture of array of non-integer are not supported. */ | |
736f2dd6 MD |
265 | WARN_ON_ONCE(1); |
266 | ret = -1; | |
267 | goto end; | |
42f3ef8c FD |
268 | } |
269 | signedness = integer_type->signedness; | |
270 | for (i = 0; i < output->u.sequence.nr_elem; i++) { | |
271 | if (signedness) { | |
272 | ret = lttng_msgpack_write_signed_integer(writer, | |
273 | capture_sequence_element_signed(ptr, integer_type)); | |
274 | if (ret) { | |
42f3ef8c FD |
275 | goto end; |
276 | } | |
277 | } else { | |
278 | ret = lttng_msgpack_write_unsigned_integer(writer, | |
279 | capture_sequence_element_unsigned(ptr, integer_type)); | |
280 | if (ret) { | |
42f3ef8c FD |
281 | goto end; |
282 | } | |
283 | } | |
284 | ||
285 | /* | |
286 | * We assume that alignment is smaller or equal to the size. | |
287 | * This currently holds true but if it changes in the future, | |
288 | * we will want to change the pointer arithmetics below to | |
289 | * take into account that the next element might be further | |
290 | * away. | |
291 | */ | |
736f2dd6 | 292 | WARN_ON_ONCE(integer_type->alignment > integer_type->size); |
42f3ef8c FD |
293 | |
294 | /* Size is in number of bits. */ | |
295 | ptr += (integer_type->size / CHAR_BIT) ; | |
296 | } | |
297 | ||
298 | ret = lttng_msgpack_end_array(writer); | |
42f3ef8c FD |
299 | end: |
300 | return ret; | |
301 | } | |
302 | ||
99d223ad FD |
303 | static |
304 | int notification_append_capture( | |
305 | struct lttng_event_notifier_notification *notif, | |
306 | struct lttng_interpreter_output *output) | |
307 | { | |
308 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
309 | int ret = 0; | |
310 | ||
311 | switch (output->type) { | |
312 | case LTTNG_INTERPRETER_TYPE_S64: | |
313 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); | |
99d223ad FD |
314 | break; |
315 | case LTTNG_INTERPRETER_TYPE_U64: | |
316 | ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u); | |
99d223ad FD |
317 | break; |
318 | case LTTNG_INTERPRETER_TYPE_STRING: | |
8915cf5e MD |
319 | if (output->u.str.user) { |
320 | ret = lttng_msgpack_write_user_str(writer, output->u.str.user_str); | |
321 | } else { | |
322 | ret = lttng_msgpack_write_str(writer, output->u.str.str); | |
323 | } | |
99d223ad FD |
324 | break; |
325 | case LTTNG_INTERPRETER_TYPE_SEQUENCE: | |
326 | ret = capture_sequence(writer, output); | |
99d223ad FD |
327 | break; |
328 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
329 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
330 | ret = capture_enum(writer, output); | |
99d223ad FD |
331 | break; |
332 | default: | |
333 | ret = -1; | |
736f2dd6 | 334 | WARN_ON_ONCE(1); |
99d223ad | 335 | } |
99d223ad FD |
336 | return ret; |
337 | } | |
338 | ||
339 | static | |
340 | int notification_append_empty_capture( | |
341 | struct lttng_event_notifier_notification *notif) | |
342 | { | |
736f2dd6 | 343 | return lttng_msgpack_write_nil(¬if->writer); |
99d223ad FD |
344 | } |
345 | ||
346 | static | |
347 | int notification_init(struct lttng_event_notifier_notification *notif, | |
a67ba386 | 348 | struct lttng_kernel_event_notifier *event_notifier) |
99d223ad FD |
349 | { |
350 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
351 | int ret = 0; | |
352 | ||
353 | notif->has_captures = false; | |
354 | ||
a67ba386 | 355 | if (event_notifier->priv->num_captures > 0) { |
99d223ad FD |
356 | lttng_msgpack_writer_init(writer, notif->capture_buf, |
357 | CAPTURE_BUFFER_SIZE); | |
358 | ||
a67ba386 | 359 | ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures); |
99d223ad | 360 | if (ret) { |
99d223ad FD |
361 | goto end; |
362 | } | |
363 | ||
364 | notif->has_captures = true; | |
365 | } | |
366 | ||
367 | end: | |
368 | return ret; | |
369 | } | |
370 | ||
99f52fcc | 371 | static |
a67ba386 | 372 | void record_error(struct lttng_kernel_event_notifier *event_notifier) |
99f52fcc FD |
373 | { |
374 | ||
a67ba386 | 375 | struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group; |
ab04d7b1 | 376 | struct lttng_counter *error_counter; |
99f52fcc FD |
377 | size_t dimension_index[1]; |
378 | int ret; | |
379 | ||
ab04d7b1 | 380 | /* |
6657edec | 381 | * lttng_smp_load_acquire paired with lttng_smp_store_release orders |
ab04d7b1 MD |
382 | * creation of the error counter and setting error_counter_len |
383 | * before the error_counter is used. | |
384 | */ | |
6657edec | 385 | error_counter = lttng_smp_load_acquire(&event_notifier_group->error_counter); |
a83d6831 | 386 | /* This group may not have an error counter attached to it. */ |
ab04d7b1 | 387 | if (!error_counter) |
a83d6831 FD |
388 | return; |
389 | ||
a67ba386 | 390 | dimension_index[0] = event_notifier->priv->error_counter_index; |
99f52fcc | 391 | |
ab04d7b1 | 392 | ret = error_counter->ops->counter_add(error_counter->counter, |
99f52fcc FD |
393 | dimension_index, 1); |
394 | if (ret) | |
395 | WARN_ON_ONCE(1); | |
396 | } | |
397 | ||
99d223ad FD |
398 | static |
399 | void notification_send(struct lttng_event_notifier_notification *notif, | |
a67ba386 | 400 | struct lttng_kernel_event_notifier *event_notifier) |
21f58fb7 | 401 | { |
a67ba386 | 402 | struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group; |
8a57ec02 | 403 | struct lttng_kernel_ring_buffer_ctx ctx; |
606828e4 | 404 | struct lttng_kernel_abi_event_notifier_notification kernel_notif; |
99d223ad | 405 | size_t capture_buffer_content_len, reserve_size; |
21f58fb7 FD |
406 | int ret; |
407 | ||
99d223ad | 408 | reserve_size = sizeof(kernel_notif); |
a67ba386 | 409 | kernel_notif.token = event_notifier->priv->parent.user_token; |
21f58fb7 | 410 | |
99d223ad FD |
411 | if (notif->has_captures) { |
412 | capture_buffer_content_len = notif->writer.write_pos - notif->writer.buffer; | |
413 | } else { | |
414 | capture_buffer_content_len = 0; | |
415 | } | |
416 | ||
417 | WARN_ON_ONCE(capture_buffer_content_len > CAPTURE_BUFFER_SIZE); | |
418 | ||
419 | reserve_size += capture_buffer_content_len; | |
420 | kernel_notif.capture_buf_size = capture_buffer_content_len; | |
421 | ||
8a445457 | 422 | lib_ring_buffer_ctx_init(&ctx, event_notifier_group->chan, reserve_size, |
b1199bd3 | 423 | lttng_alignof(kernel_notif), NULL); |
c2fb9c1c | 424 | ret = event_notifier_group->ops->event_reserve(&ctx); |
21f58fb7 | 425 | if (ret < 0) { |
99f52fcc | 426 | record_error(event_notifier); |
21f58fb7 FD |
427 | return; |
428 | } | |
99d223ad | 429 | |
99d223ad FD |
430 | /* Write the notif structure. */ |
431 | event_notifier_group->ops->event_write(&ctx, &kernel_notif, | |
f5ffbd77 | 432 | sizeof(kernel_notif), lttng_alignof(kernel_notif)); |
99d223ad FD |
433 | |
434 | /* | |
435 | * Write the capture buffer. No need to realigned as the below is a raw | |
436 | * char* buffer. | |
437 | */ | |
438 | event_notifier_group->ops->event_write(&ctx, ¬if->capture_buf, | |
f5ffbd77 | 439 | capture_buffer_content_len, 1); |
99d223ad | 440 | |
21f58fb7 FD |
441 | event_notifier_group->ops->event_commit(&ctx); |
442 | irq_work_queue(&event_notifier_group->wakeup_pending); | |
443 | } | |
99d223ad | 444 | |
a67ba386 | 445 | void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *event_notifier, |
c3eddb2e | 446 | const char *stack_data, |
a92e844e | 447 | struct lttng_kernel_probe_ctx *probe_ctx, |
a67ba386 | 448 | struct lttng_kernel_notification_ctx *notif_ctx) |
99d223ad FD |
449 | { |
450 | struct lttng_event_notifier_notification notif = { 0 }; | |
99d223ad | 451 | |
a67ba386 | 452 | if (unlikely(!READ_ONCE(event_notifier->parent.enabled))) |
99d223ad FD |
453 | return; |
454 | ||
736f2dd6 MD |
455 | if (notification_init(¬if, event_notifier)) { |
456 | record_error(event_notifier); | |
99d223ad FD |
457 | goto end; |
458 | } | |
459 | ||
c3eddb2e | 460 | if (unlikely(notif_ctx->eval_capture)) { |
218585b9 | 461 | struct lttng_kernel_bytecode_runtime *capture_bc_runtime; |
99d223ad FD |
462 | |
463 | /* | |
464 | * Iterate over all the capture bytecodes. If the interpreter | |
465 | * functions returns successfully, append the value of the | |
466 | * `output` parameter to the capture buffer. If the interpreter | |
467 | * fails, append an empty capture to the buffer. | |
468 | */ | |
c3eddb2e | 469 | list_for_each_entry_rcu(capture_bc_runtime, |
a67ba386 | 470 | &event_notifier->priv->capture_bytecode_runtime_head, node) { |
99d223ad | 471 | struct lttng_interpreter_output output; |
736f2dd6 MD |
472 | uint8_t *save_pos; |
473 | int ret; | |
99d223ad | 474 | |
736f2dd6 | 475 | lttng_msgpack_save_writer_pos(¬if.writer, &save_pos); |
8a445457 MD |
476 | if (capture_bc_runtime->interpreter_func(capture_bc_runtime, |
477 | stack_data, probe_ctx, &output) == LTTNG_KERNEL_BYTECODE_INTERPRETER_OK) | |
99d223ad FD |
478 | ret = notification_append_capture(¬if, &output); |
479 | else | |
480 | ret = notification_append_empty_capture(¬if); | |
736f2dd6 MD |
481 | if (ret) { |
482 | /* | |
483 | * On append capture error, skip the field | |
484 | * capture by restoring the msgpack writer | |
485 | * position. | |
486 | */ | |
487 | lttng_msgpack_restore_writer_pos(¬if.writer, save_pos); | |
488 | } | |
99d223ad FD |
489 | } |
490 | } | |
491 | ||
492 | /* | |
493 | * Send the notification (including the capture buffer) to the | |
494 | * sessiond. | |
495 | */ | |
496 | notification_send(¬if, event_notifier); | |
497 | end: | |
498 | return; | |
499 | } |