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d8d2416d | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-only |
d8d2416d FD |
3 | * |
4 | * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com> | |
d8d2416d FD |
5 | */ |
6 | ||
7 | #define _LGPL_SOURCE | |
8 | ||
b9f82a28 | 9 | #include <assert.h> |
d8d2416d | 10 | #include <errno.h> |
9af5d97a MJ |
11 | #include <limits.h> |
12 | ||
f03092d7 | 13 | #include <lttng/ust-endian.h> |
d8d2416d | 14 | #include <usterr-signal-safe.h> |
a2e4d05e | 15 | #include <urcu/rculist.h> |
d8d2416d | 16 | |
bb7ad29d | 17 | #include "ust-events-internal.h" |
b9f82a28 FD |
18 | #include "../libmsgpack/msgpack.h" |
19 | #include "lttng-bytecode.h" | |
864a1eda | 20 | #include "ust-share.h" |
d8d2416d | 21 | |
d37ecb3f FD |
22 | /* |
23 | * We want this write to be atomic AND non-blocking, meaning that we | |
24 | * want to write either everything OR nothing. | |
25 | * According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be | |
26 | * atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size | |
27 | * of the notification struct we are sending alongside the capture buffer. | |
28 | */ | |
29 | #define CAPTURE_BUFFER_SIZE \ | |
fd17d7ce | 30 | (PIPE_BUF - sizeof(struct lttng_ust_abi_event_notifier_notification) - 1) |
d37ecb3f FD |
31 | |
32 | struct lttng_event_notifier_notification { | |
33 | int notification_fd; | |
34 | uint64_t event_notifier_token; | |
35 | uint8_t capture_buf[CAPTURE_BUFFER_SIZE]; | |
36 | struct lttng_msgpack_writer writer; | |
37 | bool has_captures; | |
38 | }; | |
39 | ||
b9f82a28 FD |
40 | static |
41 | void capture_enum(struct lttng_msgpack_writer *writer, | |
42 | struct lttng_interpreter_output *output) | |
43 | { | |
44 | lttng_msgpack_begin_map(writer, 2); | |
45 | lttng_msgpack_write_str(writer, "type"); | |
46 | lttng_msgpack_write_str(writer, "enum"); | |
47 | ||
48 | lttng_msgpack_write_str(writer, "value"); | |
49 | ||
50 | switch (output->type) { | |
51 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
52 | lttng_msgpack_write_signed_integer(writer, output->u.s); | |
53 | break; | |
54 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
55 | lttng_msgpack_write_signed_integer(writer, output->u.u); | |
56 | break; | |
57 | default: | |
58 | abort(); | |
59 | } | |
60 | ||
61 | lttng_msgpack_end_map(writer); | |
62 | } | |
63 | ||
64 | static | |
65 | int64_t capture_sequence_element_signed(uint8_t *ptr, | |
a084756d | 66 | struct lttng_ust_type_integer *integer_type) |
b9f82a28 FD |
67 | { |
68 | int64_t value; | |
a084756d MD |
69 | unsigned int size = integer_type->size; |
70 | bool byte_order_reversed = integer_type->reverse_byte_order; | |
b9f82a28 FD |
71 | |
72 | switch (size) { | |
73 | case 8: | |
74 | value = *ptr; | |
75 | break; | |
76 | case 16: | |
77 | { | |
78 | int16_t tmp; | |
79 | tmp = *(int16_t *) ptr; | |
80 | if (byte_order_reversed) | |
81 | tmp = bswap_16(tmp); | |
82 | ||
83 | value = tmp; | |
84 | break; | |
85 | } | |
86 | case 32: | |
87 | { | |
88 | int32_t tmp; | |
89 | tmp = *(int32_t *) ptr; | |
90 | if (byte_order_reversed) | |
91 | tmp = bswap_32(tmp); | |
92 | ||
93 | value = tmp; | |
94 | break; | |
95 | } | |
96 | case 64: | |
97 | { | |
98 | int64_t tmp; | |
99 | tmp = *(int64_t *) ptr; | |
100 | if (byte_order_reversed) | |
101 | tmp = bswap_64(tmp); | |
102 | ||
103 | value = tmp; | |
104 | break; | |
105 | } | |
106 | default: | |
107 | abort(); | |
108 | } | |
109 | ||
110 | return value; | |
111 | } | |
112 | ||
113 | static | |
114 | uint64_t capture_sequence_element_unsigned(uint8_t *ptr, | |
a084756d | 115 | struct lttng_ust_type_integer *integer_type) |
b9f82a28 FD |
116 | { |
117 | uint64_t value; | |
a084756d MD |
118 | unsigned int size = integer_type->size; |
119 | bool byte_order_reversed = integer_type->reverse_byte_order; | |
b9f82a28 FD |
120 | |
121 | switch (size) { | |
122 | case 8: | |
123 | value = *ptr; | |
124 | break; | |
125 | case 16: | |
126 | { | |
127 | uint16_t tmp; | |
128 | tmp = *(uint16_t *) ptr; | |
129 | if (byte_order_reversed) | |
130 | tmp = bswap_16(tmp); | |
131 | ||
132 | value = tmp; | |
133 | break; | |
134 | } | |
135 | case 32: | |
136 | { | |
137 | uint32_t tmp; | |
138 | tmp = *(uint32_t *) ptr; | |
139 | if (byte_order_reversed) | |
140 | tmp = bswap_32(tmp); | |
141 | ||
142 | value = tmp; | |
143 | break; | |
144 | } | |
145 | case 64: | |
146 | { | |
147 | uint64_t tmp; | |
148 | tmp = *(uint64_t *) ptr; | |
149 | if (byte_order_reversed) | |
150 | tmp = bswap_64(tmp); | |
151 | ||
152 | value = tmp; | |
153 | break; | |
154 | } | |
155 | default: | |
156 | abort(); | |
157 | } | |
158 | ||
159 | return value; | |
160 | } | |
161 | ||
b9f82a28 FD |
162 | static |
163 | void capture_sequence(struct lttng_msgpack_writer *writer, | |
164 | struct lttng_interpreter_output *output) | |
165 | { | |
a084756d MD |
166 | struct lttng_ust_type_integer *integer_type; |
167 | struct lttng_ust_type_common *nested_type; | |
b9f82a28 FD |
168 | uint8_t *ptr; |
169 | bool signedness; | |
170 | int i; | |
171 | ||
172 | lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem); | |
173 | ||
174 | ptr = (uint8_t *) output->u.sequence.ptr; | |
175 | nested_type = output->u.sequence.nested_type; | |
a084756d MD |
176 | switch (nested_type->type) { |
177 | case lttng_ust_type_integer: | |
178 | integer_type = lttng_ust_get_type_integer(nested_type); | |
b9f82a28 | 179 | break; |
a084756d | 180 | case lttng_ust_type_enum: |
b9f82a28 | 181 | /* Treat enumeration as an integer. */ |
a084756d | 182 | integer_type = lttng_ust_get_type_integer(lttng_ust_get_type_enum(nested_type)->container_type); |
b9f82a28 FD |
183 | break; |
184 | default: | |
185 | /* Capture of array of non-integer are not supported. */ | |
186 | abort(); | |
187 | } | |
188 | signedness = integer_type->signedness; | |
189 | for (i = 0; i < output->u.sequence.nr_elem; i++) { | |
190 | if (signedness) { | |
191 | lttng_msgpack_write_signed_integer(writer, | |
192 | capture_sequence_element_signed(ptr, integer_type)); | |
193 | } else { | |
194 | lttng_msgpack_write_unsigned_integer(writer, | |
195 | capture_sequence_element_unsigned(ptr, integer_type)); | |
196 | } | |
197 | ||
198 | /* | |
199 | * We assume that alignment is smaller or equal to the size. | |
200 | * This currently holds true but if it changes in the future, | |
201 | * we will want to change the pointer arithmetics below to | |
202 | * take into account that the next element might be further | |
203 | * away. | |
204 | */ | |
205 | assert(integer_type->alignment <= integer_type->size); | |
206 | ||
207 | /* Size is in number of bits. */ | |
208 | ptr += (integer_type->size / CHAR_BIT) ; | |
209 | } | |
210 | ||
211 | lttng_msgpack_end_array(writer); | |
212 | } | |
213 | ||
d37ecb3f FD |
214 | static |
215 | void notification_init(struct lttng_event_notifier_notification *notif, | |
d7d45c0d | 216 | struct lttng_ust_event_notifier *event_notifier) |
d8d2416d | 217 | { |
d37ecb3f FD |
218 | struct lttng_msgpack_writer *writer = ¬if->writer; |
219 | ||
115db533 MD |
220 | notif->event_notifier_token = event_notifier->priv->parent.user_token; |
221 | notif->notification_fd = event_notifier->priv->group->notification_fd; | |
d37ecb3f FD |
222 | notif->has_captures = false; |
223 | ||
115db533 | 224 | if (event_notifier->priv->num_captures > 0) { |
d37ecb3f FD |
225 | lttng_msgpack_writer_init(writer, notif->capture_buf, |
226 | CAPTURE_BUFFER_SIZE); | |
227 | ||
115db533 | 228 | lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures); |
d37ecb3f FD |
229 | notif->has_captures = true; |
230 | } | |
231 | } | |
232 | ||
233 | static | |
234 | void notification_append_capture( | |
235 | struct lttng_event_notifier_notification *notif, | |
236 | struct lttng_interpreter_output *output) | |
237 | { | |
238 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
239 | ||
240 | switch (output->type) { | |
241 | case LTTNG_INTERPRETER_TYPE_S64: | |
242 | lttng_msgpack_write_signed_integer(writer, output->u.s); | |
243 | break; | |
244 | case LTTNG_INTERPRETER_TYPE_U64: | |
245 | lttng_msgpack_write_unsigned_integer(writer, output->u.u); | |
246 | break; | |
247 | case LTTNG_INTERPRETER_TYPE_DOUBLE: | |
248 | lttng_msgpack_write_double(writer, output->u.d); | |
249 | break; | |
250 | case LTTNG_INTERPRETER_TYPE_STRING: | |
251 | lttng_msgpack_write_str(writer, output->u.str.str); | |
252 | break; | |
253 | case LTTNG_INTERPRETER_TYPE_SEQUENCE: | |
254 | capture_sequence(writer, output); | |
255 | break; | |
256 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
257 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
258 | capture_enum(writer, output); | |
259 | break; | |
260 | default: | |
261 | abort(); | |
262 | } | |
263 | } | |
264 | ||
265 | static | |
266 | void notification_append_empty_capture( | |
267 | struct lttng_event_notifier_notification *notif) | |
268 | { | |
269 | lttng_msgpack_write_nil(¬if->writer); | |
270 | } | |
271 | ||
d7d45c0d | 272 | static void record_error(struct lttng_ust_event_notifier *event_notifier) |
6566528b FD |
273 | { |
274 | struct lttng_event_notifier_group *event_notifier_group = | |
115db533 | 275 | event_notifier->priv->group; |
33f43caa | 276 | struct lttng_counter *error_counter; |
6566528b FD |
277 | size_t dimension_index[1]; |
278 | int ret; | |
279 | ||
33f43caa MD |
280 | error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter); |
281 | /* | |
282 | * load-acquire paired with store-release orders creation of the | |
283 | * error counter and setting error_counter_len before the | |
284 | * error_counter is used. | |
285 | * Currently a full memory barrier is used, which could be | |
286 | * turned into acquire-release barriers. | |
287 | */ | |
288 | cmm_smp_mb(); | |
c30ad764 | 289 | /* This group may not have an error counter attached to it. */ |
33f43caa | 290 | if (!error_counter) |
c30ad764 MD |
291 | return; |
292 | ||
115db533 | 293 | dimension_index[0] = event_notifier->priv->error_counter_index; |
6566528b | 294 | ret = event_notifier_group->error_counter->ops->counter_add( |
33f43caa | 295 | error_counter->counter, dimension_index, 1); |
6566528b FD |
296 | if (ret) |
297 | WARN_ON_ONCE(1); | |
298 | } | |
299 | ||
d37ecb3f | 300 | static |
6566528b | 301 | void notification_send(struct lttng_event_notifier_notification *notif, |
d7d45c0d | 302 | struct lttng_ust_event_notifier *event_notifier) |
d37ecb3f FD |
303 | { |
304 | ssize_t ret; | |
305 | size_t content_len; | |
306 | int iovec_count = 1; | |
fd17d7ce | 307 | struct lttng_ust_abi_event_notifier_notification ust_notif = {0}; |
d37ecb3f FD |
308 | struct iovec iov[2]; |
309 | ||
310 | assert(notif); | |
311 | ||
115db533 | 312 | ust_notif.token = event_notifier->priv->parent.user_token; |
d37ecb3f | 313 | |
d8d2416d | 314 | /* |
d37ecb3f FD |
315 | * Prepare sending the notification from multiple buffers using an |
316 | * array of `struct iovec`. The first buffer of the vector is | |
317 | * notification structure itself and is always present. | |
d8d2416d | 318 | */ |
d37ecb3f FD |
319 | iov[0].iov_base = &ust_notif; |
320 | iov[0].iov_len = sizeof(ust_notif); | |
321 | ||
322 | if (notif->has_captures) { | |
323 | /* | |
324 | * If captures were requested, the second buffer of the array | |
325 | * is the capture buffer. | |
326 | */ | |
327 | assert(notif->writer.buffer); | |
328 | content_len = notif->writer.write_pos - notif->writer.buffer; | |
d8d2416d | 329 | |
d37ecb3f | 330 | assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE); |
d8d2416d | 331 | |
d37ecb3f FD |
332 | iov[1].iov_base = notif->capture_buf; |
333 | iov[1].iov_len = content_len; | |
334 | ||
335 | iovec_count++; | |
336 | } else { | |
337 | content_len = 0; | |
338 | } | |
339 | ||
340 | /* | |
341 | * Update the capture buffer size so that receiver of the buffer will | |
342 | * know how much to expect. | |
343 | */ | |
344 | ust_notif.capture_buf_size = content_len; | |
d8d2416d | 345 | |
d37ecb3f | 346 | /* Send all the buffers. */ |
516d12da | 347 | ret = ust_patient_writev(notif->notification_fd, iov, iovec_count); |
d8d2416d FD |
348 | if (ret == -1) { |
349 | if (errno == EAGAIN) { | |
6566528b FD |
350 | record_error(event_notifier); |
351 | DBG("Cannot send event_notifier notification without blocking: %s", | |
d8d2416d FD |
352 | strerror(errno)); |
353 | } else { | |
354 | DBG("Error to sending event notifier notification: %s", | |
355 | strerror(errno)); | |
356 | abort(); | |
357 | } | |
358 | } | |
359 | } | |
d37ecb3f | 360 | |
6566528b | 361 | void lttng_event_notifier_notification_send( |
d7d45c0d | 362 | struct lttng_ust_event_notifier *event_notifier, |
a2e4d05e MD |
363 | const char *stack_data, |
364 | struct lttng_ust_notification_ctx *notif_ctx) | |
d37ecb3f FD |
365 | { |
366 | /* | |
367 | * This function is called from the probe, we must do dynamic | |
368 | * allocation in this context. | |
369 | */ | |
370 | struct lttng_event_notifier_notification notif = {0}; | |
371 | ||
372 | notification_init(¬if, event_notifier); | |
373 | ||
a2e4d05e | 374 | if (caa_unlikely(notif_ctx->eval_capture)) { |
5469a374 | 375 | struct lttng_ust_bytecode_runtime *capture_bc_runtime; |
d37ecb3f FD |
376 | |
377 | /* | |
378 | * Iterate over all the capture bytecodes. If the interpreter | |
379 | * functions returns successfully, append the value of the | |
380 | * `output` parameter to the capture buffer. If the interpreter | |
381 | * fails, append an empty capture to the buffer. | |
382 | */ | |
a2e4d05e MD |
383 | cds_list_for_each_entry_rcu(capture_bc_runtime, |
384 | &event_notifier->priv->capture_bytecode_runtime_head, node) { | |
d37ecb3f FD |
385 | struct lttng_interpreter_output output; |
386 | ||
22c30e27 MD |
387 | if (capture_bc_runtime->interpreter_func(capture_bc_runtime, |
388 | stack_data, &output) == LTTNG_UST_BYTECODE_INTERPRETER_OK) | |
d37ecb3f FD |
389 | notification_append_capture(¬if, &output); |
390 | else | |
391 | notification_append_empty_capture(¬if); | |
392 | } | |
393 | } | |
394 | ||
395 | /* | |
396 | * Send the notification (including the capture buffer) to the | |
397 | * sessiond. | |
398 | */ | |
6566528b | 399 | notification_send(¬if, event_notifier); |
d37ecb3f | 400 | } |