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