| 1 | /* |
| 2 | * SPDX-License-Identifier: LGPL-2.1-only |
| 3 | * |
| 4 | * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com> |
| 5 | */ |
| 6 | |
| 7 | #define _LGPL_SOURCE |
| 8 | |
| 9 | #include <assert.h> |
| 10 | #include <errno.h> |
| 11 | #include <limits.h> |
| 12 | |
| 13 | #include <lttng/ust-endian.h> |
| 14 | #include "common/logging.h" |
| 15 | #include <urcu/rculist.h> |
| 16 | |
| 17 | #include "lttng-tracer-core.h" |
| 18 | #include "lib/lttng-ust/events.h" |
| 19 | #include "common/msgpack/msgpack.h" |
| 20 | #include "lttng-bytecode.h" |
| 21 | #include "common/patient.h" |
| 22 | |
| 23 | /* |
| 24 | * We want this write to be atomic AND non-blocking, meaning that we |
| 25 | * want to write either everything OR nothing. |
| 26 | * According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be |
| 27 | * atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size |
| 28 | * of the notification struct we are sending alongside the capture buffer. |
| 29 | */ |
| 30 | #define CAPTURE_BUFFER_SIZE \ |
| 31 | (PIPE_BUF - sizeof(struct lttng_ust_abi_event_notifier_notification) - 1) |
| 32 | |
| 33 | #define MSG_WRITE_NIL_LEN 1 |
| 34 | |
| 35 | struct lttng_event_notifier_notification { |
| 36 | int notification_fd; |
| 37 | uint64_t event_notifier_token; |
| 38 | uint8_t capture_buf[CAPTURE_BUFFER_SIZE]; |
| 39 | struct lttng_msgpack_writer writer; |
| 40 | bool has_captures; |
| 41 | }; |
| 42 | |
| 43 | static |
| 44 | int capture_enum(struct lttng_msgpack_writer *writer, |
| 45 | struct lttng_interpreter_output *output) |
| 46 | { |
| 47 | int ret; |
| 48 | |
| 49 | ret = lttng_msgpack_begin_map(writer, 2); |
| 50 | if (ret) { |
| 51 | goto end; |
| 52 | } |
| 53 | ret = lttng_msgpack_write_str(writer, "type"); |
| 54 | if (ret) { |
| 55 | goto end; |
| 56 | } |
| 57 | ret = lttng_msgpack_write_str(writer, "enum"); |
| 58 | if (ret) { |
| 59 | goto end; |
| 60 | } |
| 61 | ret = lttng_msgpack_write_str(writer, "value"); |
| 62 | if (ret) { |
| 63 | goto end; |
| 64 | } |
| 65 | |
| 66 | switch (output->type) { |
| 67 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: |
| 68 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); |
| 69 | if (ret) { |
| 70 | goto end; |
| 71 | } |
| 72 | break; |
| 73 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: |
| 74 | ret = lttng_msgpack_write_signed_integer(writer, output->u.u); |
| 75 | if (ret) { |
| 76 | goto end; |
| 77 | } |
| 78 | break; |
| 79 | default: |
| 80 | CRIT("Unknown enum output type\n"); |
| 81 | ret = -1; |
| 82 | goto end; |
| 83 | } |
| 84 | |
| 85 | ret = lttng_msgpack_end_map(writer); |
| 86 | end: |
| 87 | return ret; |
| 88 | } |
| 89 | |
| 90 | static |
| 91 | int64_t capture_sequence_element_signed(uint8_t *ptr, |
| 92 | const struct lttng_ust_type_integer *integer_type) |
| 93 | { |
| 94 | int64_t value; |
| 95 | unsigned int size = integer_type->size; |
| 96 | bool byte_order_reversed = integer_type->reverse_byte_order; |
| 97 | |
| 98 | switch (size) { |
| 99 | case 8: |
| 100 | value = *ptr; |
| 101 | break; |
| 102 | case 16: |
| 103 | { |
| 104 | int16_t tmp; |
| 105 | tmp = *(int16_t *) ptr; |
| 106 | if (byte_order_reversed) |
| 107 | tmp = lttng_ust_bswap_16(tmp); |
| 108 | |
| 109 | value = tmp; |
| 110 | break; |
| 111 | } |
| 112 | case 32: |
| 113 | { |
| 114 | int32_t tmp; |
| 115 | tmp = *(int32_t *) ptr; |
| 116 | if (byte_order_reversed) |
| 117 | tmp = lttng_ust_bswap_32(tmp); |
| 118 | |
| 119 | value = tmp; |
| 120 | break; |
| 121 | } |
| 122 | case 64: |
| 123 | { |
| 124 | int64_t tmp; |
| 125 | tmp = *(int64_t *) ptr; |
| 126 | if (byte_order_reversed) |
| 127 | tmp = lttng_ust_bswap_64(tmp); |
| 128 | |
| 129 | value = tmp; |
| 130 | break; |
| 131 | } |
| 132 | default: |
| 133 | CRIT("Unknown sequence element size\n"); |
| 134 | value = 0; |
| 135 | } |
| 136 | |
| 137 | return value; |
| 138 | } |
| 139 | |
| 140 | static |
| 141 | uint64_t capture_sequence_element_unsigned(uint8_t *ptr, |
| 142 | const struct lttng_ust_type_integer *integer_type) |
| 143 | { |
| 144 | uint64_t value; |
| 145 | unsigned int size = integer_type->size; |
| 146 | bool byte_order_reversed = integer_type->reverse_byte_order; |
| 147 | |
| 148 | switch (size) { |
| 149 | case 8: |
| 150 | value = *ptr; |
| 151 | break; |
| 152 | case 16: |
| 153 | { |
| 154 | uint16_t tmp; |
| 155 | tmp = *(uint16_t *) ptr; |
| 156 | if (byte_order_reversed) |
| 157 | tmp = lttng_ust_bswap_16(tmp); |
| 158 | |
| 159 | value = tmp; |
| 160 | break; |
| 161 | } |
| 162 | case 32: |
| 163 | { |
| 164 | uint32_t tmp; |
| 165 | tmp = *(uint32_t *) ptr; |
| 166 | if (byte_order_reversed) |
| 167 | tmp = lttng_ust_bswap_32(tmp); |
| 168 | |
| 169 | value = tmp; |
| 170 | break; |
| 171 | } |
| 172 | case 64: |
| 173 | { |
| 174 | uint64_t tmp; |
| 175 | tmp = *(uint64_t *) ptr; |
| 176 | if (byte_order_reversed) |
| 177 | tmp = lttng_ust_bswap_64(tmp); |
| 178 | |
| 179 | value = tmp; |
| 180 | break; |
| 181 | } |
| 182 | default: |
| 183 | CRIT("Unknown sequence element size\n"); |
| 184 | value = 0; |
| 185 | } |
| 186 | |
| 187 | return value; |
| 188 | } |
| 189 | |
| 190 | static |
| 191 | int capture_sequence(struct lttng_msgpack_writer *writer, |
| 192 | struct lttng_interpreter_output *output) |
| 193 | { |
| 194 | const struct lttng_ust_type_integer *integer_type; |
| 195 | const struct lttng_ust_type_common *nested_type; |
| 196 | uint8_t *ptr; |
| 197 | bool signedness; |
| 198 | int i, ret; |
| 199 | |
| 200 | ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem); |
| 201 | if (ret) { |
| 202 | goto end; |
| 203 | } |
| 204 | ptr = (uint8_t *) output->u.sequence.ptr; |
| 205 | nested_type = output->u.sequence.nested_type; |
| 206 | switch (nested_type->type) { |
| 207 | case lttng_ust_type_integer: |
| 208 | integer_type = lttng_ust_get_type_integer(nested_type); |
| 209 | break; |
| 210 | case lttng_ust_type_enum: |
| 211 | /* Treat enumeration as an integer. */ |
| 212 | integer_type = lttng_ust_get_type_integer(lttng_ust_get_type_enum(nested_type)->container_type); |
| 213 | break; |
| 214 | default: |
| 215 | CRIT("Capture of array of non-integer are not supported\n"); |
| 216 | ret = -1; |
| 217 | goto end; |
| 218 | } |
| 219 | signedness = integer_type->signedness; |
| 220 | for (i = 0; i < output->u.sequence.nr_elem; i++) { |
| 221 | if (signedness) { |
| 222 | ret = lttng_msgpack_write_signed_integer(writer, |
| 223 | capture_sequence_element_signed(ptr, integer_type)); |
| 224 | } else { |
| 225 | ret = lttng_msgpack_write_unsigned_integer(writer, |
| 226 | capture_sequence_element_unsigned(ptr, integer_type)); |
| 227 | } |
| 228 | if (ret) { |
| 229 | goto end; |
| 230 | } |
| 231 | |
| 232 | /* |
| 233 | * We assume that alignment is smaller or equal to the size. |
| 234 | * This currently holds true but if it changes in the future, |
| 235 | * we will want to change the pointer arithmetic below to |
| 236 | * take into account that the next element might be further |
| 237 | * away. |
| 238 | */ |
| 239 | assert(integer_type->alignment <= integer_type->size); |
| 240 | |
| 241 | /* Size is in number of bits. */ |
| 242 | ptr += (integer_type->size / CHAR_BIT) ; |
| 243 | } |
| 244 | |
| 245 | ret = lttng_msgpack_end_array(writer); |
| 246 | end: |
| 247 | return ret; |
| 248 | } |
| 249 | |
| 250 | static |
| 251 | int notification_init(struct lttng_event_notifier_notification *notif, |
| 252 | const struct lttng_ust_event_notifier *event_notifier) |
| 253 | { |
| 254 | struct lttng_msgpack_writer *writer = ¬if->writer; |
| 255 | int ret = 0; |
| 256 | |
| 257 | notif->event_notifier_token = event_notifier->priv->parent.user_token; |
| 258 | notif->notification_fd = event_notifier->priv->group->notification_fd; |
| 259 | notif->has_captures = false; |
| 260 | |
| 261 | if (event_notifier->priv->num_captures > 0) { |
| 262 | lttng_msgpack_writer_init(writer, notif->capture_buf, |
| 263 | CAPTURE_BUFFER_SIZE); |
| 264 | |
| 265 | ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures); |
| 266 | if (ret) { |
| 267 | goto end; |
| 268 | } |
| 269 | notif->has_captures = true; |
| 270 | } |
| 271 | end: |
| 272 | return ret; |
| 273 | } |
| 274 | |
| 275 | static |
| 276 | int notification_append_capture( |
| 277 | struct lttng_event_notifier_notification *notif, |
| 278 | struct lttng_interpreter_output *output) |
| 279 | { |
| 280 | struct lttng_msgpack_writer *writer = ¬if->writer; |
| 281 | int ret; |
| 282 | |
| 283 | switch (output->type) { |
| 284 | case LTTNG_INTERPRETER_TYPE_S64: |
| 285 | ret = lttng_msgpack_write_signed_integer(writer, output->u.s); |
| 286 | break; |
| 287 | case LTTNG_INTERPRETER_TYPE_U64: |
| 288 | ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u); |
| 289 | break; |
| 290 | case LTTNG_INTERPRETER_TYPE_DOUBLE: |
| 291 | ret = lttng_msgpack_write_double(writer, output->u.d); |
| 292 | break; |
| 293 | case LTTNG_INTERPRETER_TYPE_STRING: |
| 294 | ret = lttng_msgpack_write_str(writer, output->u.str.str); |
| 295 | break; |
| 296 | case LTTNG_INTERPRETER_TYPE_SEQUENCE: |
| 297 | ret = capture_sequence(writer, output); |
| 298 | break; |
| 299 | case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM: |
| 300 | case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM: |
| 301 | ret = capture_enum(writer, output); |
| 302 | break; |
| 303 | default: |
| 304 | CRIT("Unknown capture output type\n"); |
| 305 | ret = -1; |
| 306 | } |
| 307 | return ret; |
| 308 | } |
| 309 | |
| 310 | static |
| 311 | int notification_append_empty_capture( |
| 312 | struct lttng_event_notifier_notification *notif) |
| 313 | { |
| 314 | return lttng_msgpack_write_nil(¬if->writer); |
| 315 | } |
| 316 | |
| 317 | static void record_error(const struct lttng_ust_event_notifier *event_notifier) |
| 318 | { |
| 319 | struct lttng_event_notifier_group *event_notifier_group = |
| 320 | event_notifier->priv->group; |
| 321 | struct lttng_ust_channel_counter *error_counter; |
| 322 | size_t dimension_index[1]; |
| 323 | int ret; |
| 324 | |
| 325 | error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter); |
| 326 | /* |
| 327 | * load-acquire paired with store-release orders creation of the |
| 328 | * error counter and setting error_counter_len before the |
| 329 | * error_counter is used. |
| 330 | * Currently a full memory barrier is used, which could be |
| 331 | * turned into acquire-release barriers. |
| 332 | */ |
| 333 | cmm_smp_mb(); |
| 334 | /* This group may not have an error counter attached to it. */ |
| 335 | if (!error_counter) |
| 336 | return; |
| 337 | |
| 338 | dimension_index[0] = event_notifier->priv->error_counter_index; |
| 339 | ret = event_notifier_group->error_counter->ops->priv->counter_add( |
| 340 | error_counter, dimension_index, 1); |
| 341 | if (ret) |
| 342 | WARN_ON_ONCE(1); |
| 343 | } |
| 344 | |
| 345 | static |
| 346 | void notification_send(struct lttng_event_notifier_notification *notif, |
| 347 | const struct lttng_ust_event_notifier *event_notifier) |
| 348 | { |
| 349 | ssize_t ret; |
| 350 | size_t content_len; |
| 351 | int iovec_count = 1; |
| 352 | struct lttng_ust_abi_event_notifier_notification ust_notif = {0}; |
| 353 | struct iovec iov[2]; |
| 354 | |
| 355 | assert(notif); |
| 356 | |
| 357 | ust_notif.token = event_notifier->priv->parent.user_token; |
| 358 | |
| 359 | /* |
| 360 | * Prepare sending the notification from multiple buffers using an |
| 361 | * array of `struct iovec`. The first buffer of the vector is |
| 362 | * notification structure itself and is always present. |
| 363 | */ |
| 364 | iov[0].iov_base = &ust_notif; |
| 365 | iov[0].iov_len = sizeof(ust_notif); |
| 366 | |
| 367 | if (notif->has_captures) { |
| 368 | /* |
| 369 | * If captures were requested, the second buffer of the array |
| 370 | * is the capture buffer. |
| 371 | */ |
| 372 | assert(notif->writer.buffer); |
| 373 | content_len = notif->writer.write_pos - notif->writer.buffer; |
| 374 | |
| 375 | assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE); |
| 376 | |
| 377 | iov[1].iov_base = notif->capture_buf; |
| 378 | iov[1].iov_len = content_len; |
| 379 | |
| 380 | iovec_count++; |
| 381 | } else { |
| 382 | content_len = 0; |
| 383 | } |
| 384 | |
| 385 | /* |
| 386 | * Update the capture buffer size so that receiver of the buffer will |
| 387 | * know how much to expect. |
| 388 | */ |
| 389 | ust_notif.capture_buf_size = content_len; |
| 390 | |
| 391 | /* Send all the buffers. */ |
| 392 | ret = ust_patient_writev(notif->notification_fd, iov, iovec_count); |
| 393 | if (ret == -1) { |
| 394 | if (errno == EAGAIN) { |
| 395 | record_error(event_notifier); |
| 396 | DBG("Cannot send event_notifier notification without blocking: %s", |
| 397 | strerror(errno)); |
| 398 | } else { |
| 399 | DBG("Error to sending event notifier notification: %s", |
| 400 | strerror(errno)); |
| 401 | abort(); |
| 402 | } |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * Validate that the buffer has enough room to hold empty capture fields. |
| 408 | */ |
| 409 | static |
| 410 | bool validate_buffer_len(struct lttng_event_notifier_notification *notif, size_t captures_left) |
| 411 | { |
| 412 | if (notif->writer.end_write_pos - notif->writer.write_pos < MSG_WRITE_NIL_LEN * captures_left) |
| 413 | return false; |
| 414 | return true; |
| 415 | } |
| 416 | |
| 417 | void lttng_event_notifier_notification_send( |
| 418 | const struct lttng_ust_event_notifier *event_notifier, |
| 419 | const char *stack_data, |
| 420 | struct lttng_ust_probe_ctx *probe_ctx, |
| 421 | struct lttng_ust_notification_ctx *notif_ctx) |
| 422 | { |
| 423 | /* |
| 424 | * This function is called from the probe, we must do dynamic |
| 425 | * allocation in this context. |
| 426 | */ |
| 427 | struct lttng_event_notifier_notification notif = {0}; |
| 428 | size_t captures_left; |
| 429 | |
| 430 | if (notification_init(¬if, event_notifier)) |
| 431 | goto error; |
| 432 | |
| 433 | captures_left = event_notifier->priv->num_captures; |
| 434 | if (!validate_buffer_len(¬if, captures_left)) |
| 435 | goto error; |
| 436 | |
| 437 | if (caa_unlikely(notif_ctx->eval_capture)) { |
| 438 | struct lttng_ust_bytecode_runtime *capture_bc_runtime; |
| 439 | |
| 440 | /* |
| 441 | * Iterate over all the capture bytecodes. If the interpreter |
| 442 | * functions returns successfully, append the value of the |
| 443 | * `output` parameter to the capture buffer. If the interpreter |
| 444 | * fails, append an empty capture to the buffer. |
| 445 | */ |
| 446 | cds_list_for_each_entry_rcu(capture_bc_runtime, |
| 447 | &event_notifier->priv->capture_bytecode_runtime_head, node) { |
| 448 | struct lttng_interpreter_output output; |
| 449 | uint8_t *save_pos; |
| 450 | int ret = -1; |
| 451 | |
| 452 | lttng_msgpack_save_writer_pos(¬if.writer, &save_pos); |
| 453 | if (capture_bc_runtime->interpreter_func(capture_bc_runtime, |
| 454 | stack_data, probe_ctx, &output) == LTTNG_UST_BYTECODE_INTERPRETER_OK) |
| 455 | ret = notification_append_capture(¬if, &output); |
| 456 | if (ret || !validate_buffer_len(¬if, captures_left)) { |
| 457 | /* |
| 458 | * On append capture error or if the generated |
| 459 | * buffer data would not leave enough room to |
| 460 | * write empty capture fields for the remaining |
| 461 | * fields, skip the field capture by restoring |
| 462 | * the msgpack writer position and writing an |
| 463 | * empty capture field. |
| 464 | */ |
| 465 | lttng_msgpack_restore_writer_pos(¬if.writer, save_pos); |
| 466 | ret = notification_append_empty_capture(¬if); |
| 467 | if (ret) |
| 468 | CRIT("Not enough space for empty capture field\n"); |
| 469 | } |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | if (notif.has_captures && lttng_msgpack_end_array(¬if.writer)) |
| 474 | goto error; |
| 475 | |
| 476 | /* |
| 477 | * Send the notification (including the capture buffer) to the |
| 478 | * sessiond. |
| 479 | */ |
| 480 | notification_send(¬if, event_notifier); |
| 481 | return; |
| 482 | |
| 483 | error: |
| 484 | record_error(event_notifier); |
| 485 | return; |
| 486 | } |