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