liblttng-ust/lttng-ring-buffer-client.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  */
   8
   9 #include <stddef.h>
  10 #include <stdint.h>
  11 #include <lttng/ust-events.h>
  12 #include "ust-bitfield.h"
  13 #include "ust-compat.h"
  14 #include "clock.h"
  15 #include "lttng-tracer.h"
  16 #include "../libringbuffer/frontend_types.h"
  17
  18 #define LTTNG_COMPACT_EVENT_BITS       5
  19 #define LTTNG_COMPACT_TSC_BITS         27
  20
  21 enum app_ctx_mode {
  22         APP_CTX_DISABLED,
  23         APP_CTX_ENABLED,
  24 };
  25
  26 /*
  27  * Keep the natural field alignment for _each field_ within this structure if
  28  * you ever add/remove a field from this header. Packed attribute is not used
  29  * because gcc generates poor code on at least powerpc and mips. Don't ever
  30  * let gcc add padding between the structure elements.
  31  */
  32
  33 struct packet_header {
  34         /* Trace packet header */
  35         uint32_t magic;                 /*
  36                                          * Trace magic number.
  37                                          * contains endianness information.
  38                                          */
  39         uint8_t uuid[LTTNG_UST_UUID_LEN];
  40         uint32_t stream_id;
  41         uint64_t stream_instance_id;
  42
  43         struct {
  44                 /* Stream packet context */
  45                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  46                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  47                 uint64_t content_size;          /* Size of data in subbuffer */
  48                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  49                 uint64_t packet_seq_num;        /* Packet sequence number */
  50                 unsigned long events_discarded; /*
  51                                                  * Events lost in this subbuffer since
  52                                                  * the beginning of the trace.
  53                                                  * (may overflow)
  54                                                  */
  55                 uint32_t cpu_id;                /* CPU id associated with stream */
  56                 uint8_t header_end;             /* End of header */
  57         } ctx;
  58 };
  59
  60 struct lttng_client_ctx {
  61         size_t packet_context_len;
  62         size_t event_context_len;
  63 };
  64
  65 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  66 {
  67         return trace_clock_read64();
  68 }
  69
  70 static inline
  71 size_t ctx_get_aligned_size(size_t offset, struct lttng_ctx *ctx,
  72                 size_t ctx_len)
  73 {
  74         size_t orig_offset = offset;
  75
  76         if (caa_likely(!ctx))
  77                 return 0;
  78         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  79         offset += ctx_len;
  80         return offset - orig_offset;
  81 }
  82
  83 static inline
  84 void ctx_get_struct_size(struct lttng_ctx *ctx, size_t *ctx_len,
  85                 enum app_ctx_mode mode)
  86 {
  87         int i;
  88         size_t offset = 0;
  89
  90         if (caa_likely(!ctx)) {
  91                 *ctx_len = 0;
  92                 return;
  93         }
  94         for (i = 0; i < ctx->nr_fields; i++) {
  95                 if (mode == APP_CTX_ENABLED) {
  96                         offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
  97                 } else {
  98                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
  99                                 /*
 100                                  * Before UST 2.8, we cannot use the
 101                                  * application context, because we
 102                                  * cannot trust that the handler used
 103                                  * for get_size is the same used for
 104                                  * ctx_record, which would result in
 105                                  * corrupted traces when tracing
 106                                  * concurrently with application context
 107                                  * register/unregister.
 108                                  */
 109                                 offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
 110                         } else {
 111                                 offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 112                         }
 113                 }
 114         }
 115         *ctx_len = offset;
 116 }
 117
 118 static inline
 119 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 120                 struct lttng_channel *chan,
 121                 struct lttng_ctx *ctx,
 122                 enum app_ctx_mode mode)
 123 {
 124         int i;
 125
 126         if (caa_likely(!ctx))
 127                 return;
 128         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 129         for (i = 0; i < ctx->nr_fields; i++) {
 130                 if (mode == APP_CTX_ENABLED) {
 131                         ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 132                 } else {
 133                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 134                                 /*
 135                                  * Before UST 2.8, we cannot use the
 136                                  * application context, because we
 137                                  * cannot trust that the handler used
 138                                  * for get_size is the same used for
 139                                  * ctx_record, which would result in
 140                                  * corrupted traces when tracing
 141                                  * concurrently with application context
 142                                  * register/unregister.
 143                                  */
 144                                 lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
 145                         } else {
 146                                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 147                         }
 148                 }
 149         }
 150 }
 151
 152 /*
 153  * record_header_size - Calculate the header size and padding necessary.
 154  * @config: ring buffer instance configuration
 155  * @chan: channel
 156  * @offset: offset in the write buffer
 157  * @pre_header_padding: padding to add before the header (output)
 158  * @ctx: reservation context
 159  *
 160  * Returns the event header size (including padding).
 161  *
 162  * The payload must itself determine its own alignment from the biggest type it
 163  * contains.
 164  */
 165 static __inline__
 166 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 167                                  struct channel *chan, size_t offset,
 168                                  size_t *pre_header_padding,
 169                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 170                                  struct lttng_client_ctx *client_ctx)
 171 {
 172         struct lttng_channel *lttng_chan = channel_get_private(chan);
 173         struct lttng_event *event = ctx->priv;
 174         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 175         size_t orig_offset = offset;
 176         size_t padding;
 177
 178         switch (lttng_chan->header_type) {
 179         case 1: /* compact */
 180                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 181                 offset += padding;
 182                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 183                         offset += sizeof(uint32_t);     /* id and timestamp */
 184                 } else {
 185                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 186                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 187                         /* Align extended struct on largest member */
 188                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 189                         offset += sizeof(uint32_t);     /* id */
 190                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 191                         offset += sizeof(uint64_t);     /* timestamp */
 192                 }
 193                 break;
 194         case 2: /* large */
 195                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 196                 offset += padding;
 197                 offset += sizeof(uint16_t);
 198                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 199                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 200                         offset += sizeof(uint32_t);     /* timestamp */
 201                 } else {
 202                         /* Align extended struct on largest member */
 203                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 204                         offset += sizeof(uint32_t);     /* id */
 205                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 206                         offset += sizeof(uint64_t);     /* timestamp */
 207                 }
 208                 break;
 209         default:
 210                 padding = 0;
 211                 WARN_ON_ONCE(1);
 212         }
 213         if (lttng_ctx) {
 214                 /* 2.8+ probe ABI. */
 215                 offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 216                                 client_ctx->packet_context_len);
 217                 offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 218                                 client_ctx->event_context_len);
 219         } else {
 220                 /* Pre 2.8 probe ABI. */
 221                 offset += ctx_get_aligned_size(offset, lttng_chan->ctx,
 222                                 client_ctx->packet_context_len);
 223                 offset += ctx_get_aligned_size(offset, event->ctx,
 224                                 client_ctx->event_context_len);
 225         }
 226         *pre_header_padding = padding;
 227         return offset - orig_offset;
 228 }
 229
 230 #include "../libringbuffer/api.h"
 231 #include "lttng-rb-clients.h"
 232
 233 static
 234 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 235                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 236                                  uint32_t event_id);
 237
 238 /*
 239  * lttng_write_event_header
 240  *
 241  * Writes the event header to the offset (already aligned on 32-bits).
 242  *
 243  * @config: ring buffer instance configuration
 244  * @ctx: reservation context
 245  * @event_id: event ID
 246  */
 247 static __inline__
 248 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 249                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 250                             uint32_t event_id)
 251 {
 252         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 253         struct lttng_event *event = ctx->priv;
 254         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 255
 256         if (caa_unlikely(ctx->rflags))
 257                 goto slow_path;
 258
 259         switch (lttng_chan->header_type) {
 260         case 1: /* compact */
 261         {
 262                 uint32_t id_time = 0;
 263
 264                 bt_bitfield_write(&id_time, uint32_t,
 265                                 0,
 266                                 LTTNG_COMPACT_EVENT_BITS,
 267                                 event_id);
 268                 bt_bitfield_write(&id_time, uint32_t,
 269                                 LTTNG_COMPACT_EVENT_BITS,
 270                                 LTTNG_COMPACT_TSC_BITS,
 271                                 ctx->tsc);
 272                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 273                 break;
 274         }
 275         case 2: /* large */
 276         {
 277                 uint32_t timestamp = (uint32_t) ctx->tsc;
 278                 uint16_t id = event_id;
 279
 280                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 281                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 282                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 283                 break;
 284         }
 285         default:
 286                 WARN_ON_ONCE(1);
 287         }
 288
 289         if (lttng_ctx) {
 290                 /* 2.8+ probe ABI. */
 291                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 292                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 293         } else {
 294                 /* Pre 2.8 probe ABI. */
 295                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 296                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 297         }
 298         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 299
 300         return;
 301
 302 slow_path:
 303         lttng_write_event_header_slow(config, ctx, event_id);
 304 }
 305
 306 static
 307 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 308                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 309                                  uint32_t event_id)
 310 {
 311         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 312         struct lttng_event *event = ctx->priv;
 313         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 314
 315         switch (lttng_chan->header_type) {
 316         case 1: /* compact */
 317                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 318                         uint32_t id_time = 0;
 319
 320                         bt_bitfield_write(&id_time, uint32_t,
 321                                         0,
 322                                         LTTNG_COMPACT_EVENT_BITS,
 323                                         event_id);
 324                         bt_bitfield_write(&id_time, uint32_t,
 325                                         LTTNG_COMPACT_EVENT_BITS,
 326                                         LTTNG_COMPACT_TSC_BITS,
 327                                         ctx->tsc);
 328                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 329                 } else {
 330                         uint8_t id = 0;
 331                         uint64_t timestamp = ctx->tsc;
 332
 333                         bt_bitfield_write(&id, uint8_t,
 334                                         0,
 335                                         LTTNG_COMPACT_EVENT_BITS,
 336                                         31);
 337                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 338                         /* Align extended struct on largest member */
 339                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 340                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 341                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 342                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 343                 }
 344                 break;
 345         case 2: /* large */
 346         {
 347                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 348                         uint32_t timestamp = (uint32_t) ctx->tsc;
 349                         uint16_t id = event_id;
 350
 351                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 352                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 353                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 354                 } else {
 355                         uint16_t id = 65535;
 356                         uint64_t timestamp = ctx->tsc;
 357
 358                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 359                         /* Align extended struct on largest member */
 360                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 361                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 362                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 363                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 364                 }
 365                 break;
 366         }
 367         default:
 368                 WARN_ON_ONCE(1);
 369         }
 370         if (lttng_ctx) {
 371                 /* 2.8+ probe ABI. */
 372                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 373                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 374         } else {
 375                 /* Pre 2.8 probe ABI. */
 376                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 377                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 378         }
 379         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 380 }
 381
 382 static const struct lttng_ust_lib_ring_buffer_config client_config;
 383
 384 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 385 {
 386         return lib_ring_buffer_clock_read(chan);
 387 }
 388
 389 static
 390 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 391                                  struct channel *chan, size_t offset,
 392                                  size_t *pre_header_padding,
 393                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 394                                  void *client_ctx)
 395 {
 396         return record_header_size(config, chan, offset,
 397                                   pre_header_padding, ctx, client_ctx);
 398 }
 399
 400 /**
 401  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 402  *
 403  * Return header size without padding after the structure. Don't use packed
 404  * structure because gcc generates inefficient code on some architectures
 405  * (powerpc, mips..)
 406  */
 407 static size_t client_packet_header_size(void)
 408 {
 409         return offsetof(struct packet_header, ctx.header_end);
 410 }
 411
 412 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 413                                 unsigned int subbuf_idx,
 414                                 struct lttng_ust_shm_handle *handle)
 415 {
 416         struct channel *chan = shmp(handle, buf->backend.chan);
 417         struct packet_header *header =
 418                 (struct packet_header *)
 419                         lib_ring_buffer_offset_address(&buf->backend,
 420                                 subbuf_idx * chan->backend.subbuf_size,
 421                                 handle);
 422         struct lttng_channel *lttng_chan = channel_get_private(chan);
 423         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 424
 425         assert(header);
 426         if (!header)
 427                 return;
 428         header->magic = CTF_MAGIC_NUMBER;
 429         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 430         header->stream_id = lttng_chan->id;
 431         header->stream_instance_id = buf->backend.cpu;
 432         header->ctx.timestamp_begin = tsc;
 433         header->ctx.timestamp_end = 0;
 434         header->ctx.content_size = ~0ULL; /* for debugging */
 435         header->ctx.packet_size = ~0ULL;
 436         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 437         header->ctx.events_discarded = 0;
 438         header->ctx.cpu_id = buf->backend.cpu;
 439 }
 440
 441 /*
 442  * offset is assumed to never be 0 here : never deliver a completely empty
 443  * subbuffer. data_size is between 1 and subbuf_size.
 444  */
 445 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 446                               unsigned int subbuf_idx, unsigned long data_size,
 447                               struct lttng_ust_shm_handle *handle)
 448 {
 449         struct channel *chan = shmp(handle, buf->backend.chan);
 450         struct packet_header *header =
 451                 (struct packet_header *)
 452                         lib_ring_buffer_offset_address(&buf->backend,
 453                                 subbuf_idx * chan->backend.subbuf_size,
 454                                 handle);
 455         unsigned long records_lost = 0;
 456
 457         assert(header);
 458         if (!header)
 459                 return;
 460         header->ctx.timestamp_end = tsc;
 461         header->ctx.content_size =
 462                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 463         header->ctx.packet_size =
 464                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 465
 466         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 467         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 468         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 469         header->ctx.events_discarded = records_lost;
 470 }
 471
 472 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 473                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 474 {
 475         return 0;
 476 }
 477
 478 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 479 {
 480 }
 481
 482 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 483                                       size_t *offset, size_t *length)
 484 {
 485         *offset = offsetof(struct packet_header, ctx.content_size);
 486         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 487 }
 488
 489 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 490                                       size_t *offset, size_t *length)
 491 {
 492         *offset = offsetof(struct packet_header, ctx.packet_size);
 493         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 494 }
 495
 496 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 497                 struct lttng_ust_shm_handle *handle)
 498 {
 499         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 500 }
 501
 502 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 503                 struct lttng_ust_shm_handle *handle,
 504                 uint64_t *timestamp_begin)
 505 {
 506         struct packet_header *header;
 507
 508         header = client_packet_header(buf, handle);
 509         if (!header)
 510                 return -1;
 511         *timestamp_begin = header->ctx.timestamp_begin;
 512         return 0;
 513 }
 514
 515 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 516                 struct lttng_ust_shm_handle *handle,
 517                 uint64_t *timestamp_end)
 518 {
 519         struct packet_header *header;
 520
 521         header = client_packet_header(buf, handle);
 522         if (!header)
 523                 return -1;
 524         *timestamp_end = header->ctx.timestamp_end;
 525         return 0;
 526 }
 527
 528 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 529                 struct lttng_ust_shm_handle *handle,
 530                 uint64_t *events_discarded)
 531 {
 532         struct packet_header *header;
 533
 534         header = client_packet_header(buf, handle);
 535         if (!header)
 536                 return -1;
 537         *events_discarded = header->ctx.events_discarded;
 538         return 0;
 539 }
 540
 541 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 542                 struct lttng_ust_shm_handle *handle,
 543                 uint64_t *content_size)
 544 {
 545         struct packet_header *header;
 546
 547         header = client_packet_header(buf, handle);
 548         if (!header)
 549                 return -1;
 550         *content_size = header->ctx.content_size;
 551         return 0;
 552 }
 553
 554 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 555                 struct lttng_ust_shm_handle *handle,
 556                 uint64_t *packet_size)
 557 {
 558         struct packet_header *header;
 559
 560         header = client_packet_header(buf, handle);
 561         if (!header)
 562                 return -1;
 563         *packet_size = header->ctx.packet_size;
 564         return 0;
 565 }
 566
 567 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 568                 struct lttng_ust_shm_handle *handle,
 569                 uint64_t *stream_id)
 570 {
 571         struct channel *chan = shmp(handle, buf->backend.chan);
 572         struct lttng_channel *lttng_chan = channel_get_private(chan);
 573
 574         *stream_id = lttng_chan->id;
 575
 576         return 0;
 577 }
 578
 579 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 580                 struct lttng_ust_shm_handle *handle,
 581                 uint64_t *ts)
 582 {
 583         struct channel *chan;
 584
 585         chan = shmp(handle, handle->chan);
 586         *ts = client_ring_buffer_clock_read(chan);
 587
 588         return 0;
 589 }
 590
 591 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 592                 struct lttng_ust_shm_handle *handle,
 593                 uint64_t *seq)
 594 {
 595         struct packet_header *header;
 596
 597         header = client_packet_header(buf, handle);
 598         if (!header)
 599                 return -1;
 600         *seq = header->ctx.packet_seq_num;
 601         return 0;
 602 }
 603
 604 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 605                 struct lttng_ust_shm_handle *handle,
 606                 uint64_t *id)
 607 {
 608         *id = buf->backend.cpu;
 609
 610         return 0;
 611 }
 612
 613 static const
 614 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 615         .parent = {
 616                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 617                 .record_header_size = client_record_header_size,
 618                 .subbuffer_header_size = client_packet_header_size,
 619                 .buffer_begin = client_buffer_begin,
 620                 .buffer_end = client_buffer_end,
 621                 .buffer_create = client_buffer_create,
 622                 .buffer_finalize = client_buffer_finalize,
 623                 .content_size_field = client_content_size_field,
 624                 .packet_size_field = client_packet_size_field,
 625         },
 626         .timestamp_begin = client_timestamp_begin,
 627         .timestamp_end = client_timestamp_end,
 628         .events_discarded = client_events_discarded,
 629         .content_size = client_content_size,
 630         .packet_size = client_packet_size,
 631         .stream_id = client_stream_id,
 632         .current_timestamp = client_current_timestamp,
 633         .sequence_number = client_sequence_number,
 634         .instance_id = client_instance_id,
 635 };
 636
 637 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 638         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 639         .cb.record_header_size = client_record_header_size,
 640         .cb.subbuffer_header_size = client_packet_header_size,
 641         .cb.buffer_begin = client_buffer_begin,
 642         .cb.buffer_end = client_buffer_end,
 643         .cb.buffer_create = client_buffer_create,
 644         .cb.buffer_finalize = client_buffer_finalize,
 645         .cb.content_size_field = client_content_size_field,
 646         .cb.packet_size_field = client_packet_size_field,
 647
 648         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 649         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 650         .sync = RING_BUFFER_SYNC_GLOBAL,
 651         .mode = RING_BUFFER_MODE_TEMPLATE,
 652         .backend = RING_BUFFER_PAGE,
 653         .output = RING_BUFFER_MMAP,
 654         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 655         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 656         .wakeup = LTTNG_CLIENT_WAKEUP,
 657         .client_type = LTTNG_CLIENT_TYPE,
 658
 659         .cb_ptr = &client_cb.parent,
 660 };
 661
 662 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 663
 664 static
 665 struct lttng_channel *_channel_create(const char *name,
 666                                 void *buf_addr,
 667                                 size_t subbuf_size, size_t num_subbuf,
 668                                 unsigned int switch_timer_interval,
 669                                 unsigned int read_timer_interval,
 670                                 unsigned char *uuid,
 671                                 uint32_t chan_id,
 672                                 const int *stream_fds, int nr_stream_fds,
 673                                 int64_t blocking_timeout)
 674 {
 675         struct lttng_channel chan_priv_init;
 676         struct lttng_ust_shm_handle *handle;
 677         struct lttng_channel *lttng_chan;
 678         void *priv;
 679
 680         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 681         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 682         chan_priv_init.id = chan_id;
 683         handle = channel_create(&client_config, name,
 684                         &priv, __alignof__(struct lttng_channel),
 685                         sizeof(struct lttng_channel),
 686                         &chan_priv_init,
 687                         buf_addr, subbuf_size, num_subbuf,
 688                         switch_timer_interval, read_timer_interval,
 689                         stream_fds, nr_stream_fds, blocking_timeout);
 690         if (!handle)
 691                 return NULL;
 692         lttng_chan = priv;
 693         lttng_chan->handle = handle;
 694         lttng_chan->chan = shmp(handle, handle->chan);
 695         return lttng_chan;
 696 }
 697
 698 static
 699 void lttng_channel_destroy(struct lttng_channel *chan)
 700 {
 701         channel_destroy(chan->chan, chan->handle, 1);
 702 }
 703
 704 static
 705 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 706                       uint32_t event_id)
 707 {
 708         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 709         struct lttng_event *event = ctx->priv;
 710         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 711         struct lttng_client_ctx client_ctx;
 712         int ret, cpu;
 713
 714         /* Compute internal size of context structures. */
 715
 716         if (lttng_ctx) {
 717                 /* 2.8+ probe ABI. */
 718                 ctx_get_struct_size(lttng_ctx->chan_ctx, &client_ctx.packet_context_len,
 719                                 APP_CTX_ENABLED);
 720                 ctx_get_struct_size(lttng_ctx->event_ctx, &client_ctx.event_context_len,
 721                                 APP_CTX_ENABLED);
 722         } else {
 723                 /* Pre 2.8 probe ABI. */
 724                 ctx_get_struct_size(lttng_chan->ctx, &client_ctx.packet_context_len,
 725                                 APP_CTX_DISABLED);
 726                 ctx_get_struct_size(event->ctx, &client_ctx.event_context_len,
 727                                 APP_CTX_DISABLED);
 728         }
 729
 730         cpu = lib_ring_buffer_get_cpu(&client_config);
 731         if (cpu < 0)
 732                 return -EPERM;
 733         ctx->cpu = cpu;
 734
 735         switch (lttng_chan->header_type) {
 736         case 1: /* compact */
 737                 if (event_id > 30)
 738                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 739                 break;
 740         case 2: /* large */
 741                 if (event_id > 65534)
 742                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 743                 break;
 744         default:
 745                 WARN_ON_ONCE(1);
 746         }
 747
 748         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 749         if (caa_unlikely(ret))
 750                 goto put;
 751         if (caa_likely(ctx->ctx_len
 752                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 753                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 754                                 &ctx->backend_pages)) {
 755                         ret = -EPERM;
 756                         goto put;
 757                 }
 758         }
 759         lttng_write_event_header(&client_config, ctx, event_id);
 760         return 0;
 761 put:
 762         lib_ring_buffer_put_cpu(&client_config);
 763         return ret;
 764 }
 765
 766 static
 767 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 768 {
 769         lib_ring_buffer_commit(&client_config, ctx);
 770         lib_ring_buffer_put_cpu(&client_config);
 771 }
 772
 773 static
 774 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 775                      size_t len)
 776 {
 777         lib_ring_buffer_write(&client_config, ctx, src, len);
 778 }
 779
 780 static
 781 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 782                      size_t len)
 783 {
 784         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 785 }
 786
 787 #if 0
 788 static
 789 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 790 {
 791         return &chan->read_wait;
 792 }
 793
 794 static
 795 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 796 {
 797         return &chan->hp_wait;
 798 }
 799 #endif //0
 800
 801 static
 802 int lttng_is_finalized(struct channel *chan)
 803 {
 804         return lib_ring_buffer_channel_is_finalized(chan);
 805 }
 806
 807 static
 808 int lttng_is_disabled(struct channel *chan)
 809 {
 810         return lib_ring_buffer_channel_is_disabled(chan);
 811 }
 812
 813 static
 814 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 815 {
 816         struct lttng_ust_lib_ring_buffer *buf;
 817         int cpu;
 818
 819         for_each_channel_cpu(cpu, chan) {
 820                 int shm_fd, wait_fd, wakeup_fd;
 821                 uint64_t memory_map_size;
 822
 823                 buf = channel_get_ring_buffer(&client_config, chan,
 824                                 cpu, handle, &shm_fd, &wait_fd,
 825                                 &wakeup_fd, &memory_map_size);
 826                 lib_ring_buffer_switch(&client_config, buf,
 827                                 SWITCH_ACTIVE, handle);
 828         }
 829         return 0;
 830 }
 831
 832 static struct lttng_transport lttng_relay_transport = {
 833         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 834         .ops = {
 835                 .channel_create = _channel_create,
 836                 .channel_destroy = lttng_channel_destroy,
 837                 .event_reserve = lttng_event_reserve,
 838                 .event_commit = lttng_event_commit,
 839                 .event_write = lttng_event_write,
 840                 .packet_avail_size = NULL,      /* Would be racy anyway */
 841                 .is_finalized = lttng_is_finalized,
 842                 .is_disabled = lttng_is_disabled,
 843                 .flush_buffer = lttng_flush_buffer,
 844                 .event_strcpy = lttng_event_strcpy,
 845         },
 846         .client_config = &client_config,
 847 };
 848
 849 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 850 {
 851         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 852                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 853         lttng_transport_register(&lttng_relay_transport);
 854 }
 855
 856 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 857 {
 858         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 859                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 860         lttng_transport_unregister(&lttng_relay_transport);
 861 }