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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 FD |
10 | #include <errno.h> |
11 | #include <lttng/ust-events.h> | |
f03092d7 | 12 | #include <lttng/ust-endian.h> |
d8d2416d FD |
13 | #include <usterr-signal-safe.h> |
14 | ||
b9f82a28 FD |
15 | #include "../libmsgpack/msgpack.h" |
16 | #include "lttng-bytecode.h" | |
864a1eda | 17 | #include "ust-share.h" |
d8d2416d | 18 | |
d37ecb3f FD |
19 | /* |
20 | * We want this write to be atomic AND non-blocking, meaning that we | |
21 | * want to write either everything OR nothing. | |
22 | * According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be | |
23 | * atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size | |
24 | * of the notification struct we are sending alongside the capture buffer. | |
25 | */ | |
26 | #define CAPTURE_BUFFER_SIZE \ | |
27 | (PIPE_BUF - sizeof(struct lttng_ust_event_notifier_notification) - 1) | |
28 | ||
29 | struct lttng_event_notifier_notification { | |
30 | int notification_fd; | |
31 | uint64_t event_notifier_token; | |
32 | uint8_t capture_buf[CAPTURE_BUFFER_SIZE]; | |
33 | struct lttng_msgpack_writer writer; | |
34 | bool has_captures; | |
35 | }; | |
36 | ||
b9f82a28 FD |
37 | static |
38 | void capture_enum(struct lttng_msgpack_writer *writer, | |
39 | struct lttng_interpreter_output *output) | |
40 | { | |
41 | lttng_msgpack_begin_map(writer, 2); | |
42 | lttng_msgpack_write_str(writer, "type"); | |
43 | lttng_msgpack_write_str(writer, "enum"); | |
44 | ||
45 | lttng_msgpack_write_str(writer, "value"); | |
46 | ||
47 | switch (output->type) { | |
48 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
49 | lttng_msgpack_write_signed_integer(writer, output->u.s); | |
50 | break; | |
51 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
52 | lttng_msgpack_write_signed_integer(writer, output->u.u); | |
53 | break; | |
54 | default: | |
55 | abort(); | |
56 | } | |
57 | ||
58 | lttng_msgpack_end_map(writer); | |
59 | } | |
60 | ||
61 | static | |
62 | int64_t capture_sequence_element_signed(uint8_t *ptr, | |
63 | const struct lttng_integer_type *type) | |
64 | { | |
65 | int64_t value; | |
66 | unsigned int size = type->size; | |
67 | bool byte_order_reversed = type->reverse_byte_order; | |
68 | ||
69 | switch (size) { | |
70 | case 8: | |
71 | value = *ptr; | |
72 | break; | |
73 | case 16: | |
74 | { | |
75 | int16_t tmp; | |
76 | tmp = *(int16_t *) ptr; | |
77 | if (byte_order_reversed) | |
78 | tmp = bswap_16(tmp); | |
79 | ||
80 | value = tmp; | |
81 | break; | |
82 | } | |
83 | case 32: | |
84 | { | |
85 | int32_t tmp; | |
86 | tmp = *(int32_t *) ptr; | |
87 | if (byte_order_reversed) | |
88 | tmp = bswap_32(tmp); | |
89 | ||
90 | value = tmp; | |
91 | break; | |
92 | } | |
93 | case 64: | |
94 | { | |
95 | int64_t tmp; | |
96 | tmp = *(int64_t *) ptr; | |
97 | if (byte_order_reversed) | |
98 | tmp = bswap_64(tmp); | |
99 | ||
100 | value = tmp; | |
101 | break; | |
102 | } | |
103 | default: | |
104 | abort(); | |
105 | } | |
106 | ||
107 | return value; | |
108 | } | |
109 | ||
110 | static | |
111 | uint64_t capture_sequence_element_unsigned(uint8_t *ptr, | |
112 | const struct lttng_integer_type *type) | |
113 | { | |
114 | uint64_t value; | |
115 | unsigned int size = type->size; | |
116 | bool byte_order_reversed = type->reverse_byte_order; | |
117 | ||
118 | switch (size) { | |
119 | case 8: | |
120 | value = *ptr; | |
121 | break; | |
122 | case 16: | |
123 | { | |
124 | uint16_t tmp; | |
125 | tmp = *(uint16_t *) ptr; | |
126 | if (byte_order_reversed) | |
127 | tmp = bswap_16(tmp); | |
128 | ||
129 | value = tmp; | |
130 | break; | |
131 | } | |
132 | case 32: | |
133 | { | |
134 | uint32_t tmp; | |
135 | tmp = *(uint32_t *) ptr; | |
136 | if (byte_order_reversed) | |
137 | tmp = bswap_32(tmp); | |
138 | ||
139 | value = tmp; | |
140 | break; | |
141 | } | |
142 | case 64: | |
143 | { | |
144 | uint64_t tmp; | |
145 | tmp = *(uint64_t *) ptr; | |
146 | if (byte_order_reversed) | |
147 | tmp = bswap_64(tmp); | |
148 | ||
149 | value = tmp; | |
150 | break; | |
151 | } | |
152 | default: | |
153 | abort(); | |
154 | } | |
155 | ||
156 | return value; | |
157 | } | |
158 | ||
b9f82a28 FD |
159 | static |
160 | void capture_sequence(struct lttng_msgpack_writer *writer, | |
161 | struct lttng_interpreter_output *output) | |
162 | { | |
163 | const struct lttng_integer_type *integer_type; | |
164 | const struct lttng_type *nested_type; | |
165 | uint8_t *ptr; | |
166 | bool signedness; | |
167 | int i; | |
168 | ||
169 | lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem); | |
170 | ||
171 | ptr = (uint8_t *) output->u.sequence.ptr; | |
172 | nested_type = output->u.sequence.nested_type; | |
173 | switch (nested_type->atype) { | |
174 | case atype_integer: | |
175 | integer_type = &nested_type->u.integer; | |
176 | break; | |
177 | case atype_enum: | |
178 | /* Treat enumeration as an integer. */ | |
179 | integer_type = &nested_type->u.enum_nestable.container_type->u.integer; | |
180 | break; | |
181 | default: | |
182 | /* Capture of array of non-integer are not supported. */ | |
183 | abort(); | |
184 | } | |
185 | signedness = integer_type->signedness; | |
186 | for (i = 0; i < output->u.sequence.nr_elem; i++) { | |
187 | if (signedness) { | |
188 | lttng_msgpack_write_signed_integer(writer, | |
189 | capture_sequence_element_signed(ptr, integer_type)); | |
190 | } else { | |
191 | lttng_msgpack_write_unsigned_integer(writer, | |
192 | capture_sequence_element_unsigned(ptr, integer_type)); | |
193 | } | |
194 | ||
195 | /* | |
196 | * We assume that alignment is smaller or equal to the size. | |
197 | * This currently holds true but if it changes in the future, | |
198 | * we will want to change the pointer arithmetics below to | |
199 | * take into account that the next element might be further | |
200 | * away. | |
201 | */ | |
202 | assert(integer_type->alignment <= integer_type->size); | |
203 | ||
204 | /* Size is in number of bits. */ | |
205 | ptr += (integer_type->size / CHAR_BIT) ; | |
206 | } | |
207 | ||
208 | lttng_msgpack_end_array(writer); | |
209 | } | |
210 | ||
d37ecb3f FD |
211 | static |
212 | void notification_init(struct lttng_event_notifier_notification *notif, | |
d8d2416d FD |
213 | struct lttng_event_notifier *event_notifier) |
214 | { | |
d37ecb3f FD |
215 | struct lttng_msgpack_writer *writer = ¬if->writer; |
216 | ||
217 | notif->event_notifier_token = event_notifier->user_token; | |
218 | notif->notification_fd = event_notifier->group->notification_fd; | |
219 | notif->has_captures = false; | |
220 | ||
221 | if (event_notifier->num_captures > 0) { | |
222 | lttng_msgpack_writer_init(writer, notif->capture_buf, | |
223 | CAPTURE_BUFFER_SIZE); | |
224 | ||
225 | lttng_msgpack_begin_array(writer, event_notifier->num_captures); | |
226 | notif->has_captures = true; | |
227 | } | |
228 | } | |
229 | ||
230 | static | |
231 | void notification_append_capture( | |
232 | struct lttng_event_notifier_notification *notif, | |
233 | struct lttng_interpreter_output *output) | |
234 | { | |
235 | struct lttng_msgpack_writer *writer = ¬if->writer; | |
236 | ||
237 | switch (output->type) { | |
238 | case LTTNG_INTERPRETER_TYPE_S64: | |
239 | lttng_msgpack_write_signed_integer(writer, output->u.s); | |
240 | break; | |
241 | case LTTNG_INTERPRETER_TYPE_U64: | |
242 | lttng_msgpack_write_unsigned_integer(writer, output->u.u); | |
243 | break; | |
244 | case LTTNG_INTERPRETER_TYPE_DOUBLE: | |
245 | lttng_msgpack_write_double(writer, output->u.d); | |
246 | break; | |
247 | case LTTNG_INTERPRETER_TYPE_STRING: | |
248 | lttng_msgpack_write_str(writer, output->u.str.str); | |
249 | break; | |
250 | case LTTNG_INTERPRETER_TYPE_SEQUENCE: | |
251 | capture_sequence(writer, output); | |
252 | break; | |
253 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: | |
254 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: | |
255 | capture_enum(writer, output); | |
256 | break; | |
257 | default: | |
258 | abort(); | |
259 | } | |
260 | } | |
261 | ||
262 | static | |
263 | void notification_append_empty_capture( | |
264 | struct lttng_event_notifier_notification *notif) | |
265 | { | |
266 | lttng_msgpack_write_nil(¬if->writer); | |
267 | } | |
268 | ||
6566528b FD |
269 | static void record_error(struct lttng_event_notifier *event_notifier) |
270 | { | |
271 | struct lttng_event_notifier_group *event_notifier_group = | |
272 | event_notifier->group; | |
33f43caa | 273 | struct lttng_counter *error_counter; |
6566528b FD |
274 | size_t dimension_index[1]; |
275 | int ret; | |
276 | ||
33f43caa MD |
277 | error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter); |
278 | /* | |
279 | * load-acquire paired with store-release orders creation of the | |
280 | * error counter and setting error_counter_len before the | |
281 | * error_counter is used. | |
282 | * Currently a full memory barrier is used, which could be | |
283 | * turned into acquire-release barriers. | |
284 | */ | |
285 | cmm_smp_mb(); | |
c30ad764 | 286 | /* This group may not have an error counter attached to it. */ |
33f43caa | 287 | if (!error_counter) |
c30ad764 MD |
288 | return; |
289 | ||
6566528b FD |
290 | dimension_index[0] = event_notifier->error_counter_index; |
291 | ret = event_notifier_group->error_counter->ops->counter_add( | |
33f43caa | 292 | error_counter->counter, dimension_index, 1); |
6566528b FD |
293 | if (ret) |
294 | WARN_ON_ONCE(1); | |
295 | } | |
296 | ||
d37ecb3f | 297 | static |
6566528b FD |
298 | void notification_send(struct lttng_event_notifier_notification *notif, |
299 | struct lttng_event_notifier *event_notifier) | |
d37ecb3f FD |
300 | { |
301 | ssize_t ret; | |
302 | size_t content_len; | |
303 | int iovec_count = 1; | |
abbb25fd | 304 | struct lttng_ust_event_notifier_notification ust_notif = {0}; |
d37ecb3f FD |
305 | struct iovec iov[2]; |
306 | ||
307 | assert(notif); | |
308 | ||
6566528b | 309 | ust_notif.token = event_notifier->user_token; |
d37ecb3f | 310 | |
d8d2416d | 311 | /* |
d37ecb3f FD |
312 | * Prepare sending the notification from multiple buffers using an |
313 | * array of `struct iovec`. The first buffer of the vector is | |
314 | * notification structure itself and is always present. | |
d8d2416d | 315 | */ |
d37ecb3f FD |
316 | iov[0].iov_base = &ust_notif; |
317 | iov[0].iov_len = sizeof(ust_notif); | |
318 | ||
319 | if (notif->has_captures) { | |
320 | /* | |
321 | * If captures were requested, the second buffer of the array | |
322 | * is the capture buffer. | |
323 | */ | |
324 | assert(notif->writer.buffer); | |
325 | content_len = notif->writer.write_pos - notif->writer.buffer; | |
d8d2416d | 326 | |
d37ecb3f | 327 | assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE); |
d8d2416d | 328 | |
d37ecb3f FD |
329 | iov[1].iov_base = notif->capture_buf; |
330 | iov[1].iov_len = content_len; | |
331 | ||
332 | iovec_count++; | |
333 | } else { | |
334 | content_len = 0; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Update the capture buffer size so that receiver of the buffer will | |
339 | * know how much to expect. | |
340 | */ | |
341 | ust_notif.capture_buf_size = content_len; | |
d8d2416d | 342 | |
d37ecb3f | 343 | /* Send all the buffers. */ |
516d12da | 344 | ret = ust_patient_writev(notif->notification_fd, iov, iovec_count); |
d8d2416d FD |
345 | if (ret == -1) { |
346 | if (errno == EAGAIN) { | |
6566528b FD |
347 | record_error(event_notifier); |
348 | DBG("Cannot send event_notifier notification without blocking: %s", | |
d8d2416d FD |
349 | strerror(errno)); |
350 | } else { | |
351 | DBG("Error to sending event notifier notification: %s", | |
352 | strerror(errno)); | |
353 | abort(); | |
354 | } | |
355 | } | |
356 | } | |
d37ecb3f | 357 | |
6566528b FD |
358 | void lttng_event_notifier_notification_send( |
359 | struct lttng_event_notifier *event_notifier, | |
d37ecb3f FD |
360 | const char *stack_data) |
361 | { | |
362 | /* | |
363 | * This function is called from the probe, we must do dynamic | |
364 | * allocation in this context. | |
365 | */ | |
366 | struct lttng_event_notifier_notification notif = {0}; | |
367 | ||
368 | notification_init(¬if, event_notifier); | |
369 | ||
370 | if (caa_unlikely(!cds_list_empty(&event_notifier->capture_bytecode_runtime_head))) { | |
371 | struct lttng_bytecode_runtime *capture_bc_runtime; | |
372 | ||
373 | /* | |
374 | * Iterate over all the capture bytecodes. If the interpreter | |
375 | * functions returns successfully, append the value of the | |
376 | * `output` parameter to the capture buffer. If the interpreter | |
377 | * fails, append an empty capture to the buffer. | |
378 | */ | |
379 | cds_list_for_each_entry(capture_bc_runtime, | |
380 | &event_notifier->capture_bytecode_runtime_head, node) { | |
381 | struct lttng_interpreter_output output; | |
382 | ||
383 | if (capture_bc_runtime->interpreter_funcs.capture(capture_bc_runtime, | |
384 | stack_data, &output) & LTTNG_INTERPRETER_RECORD_FLAG) | |
385 | notification_append_capture(¬if, &output); | |
386 | else | |
387 | notification_append_empty_capture(¬if); | |
388 | } | |
389 | } | |
390 | ||
391 | /* | |
392 | * Send the notification (including the capture buffer) to the | |
393 | * sessiond. | |
394 | */ | |
6566528b | 395 | notification_send(¬if, event_notifier); |
d37ecb3f | 396 | } |