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