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 <limits.h>
  10 #include <stddef.h>
  11 #include <stdint.h>
  12
  13 #include <ust-events-internal.h>
  14 #include <lttng/urcu/pointer.h>
  15 #include "ust-bitfield.h"
  16 #include "ust-compat.h"
  17 #include "clock.h"
  18 #include "context-internal.h"
  19 #include "lttng-tracer.h"
  20 #include "../libringbuffer/frontend_types.h"
  21
  22 #define LTTNG_COMPACT_EVENT_BITS       5
  23 #define LTTNG_COMPACT_TSC_BITS         27
  24
  25 enum app_ctx_mode {
  26         APP_CTX_DISABLED,
  27         APP_CTX_ENABLED,
  28 };
  29
  30 /*
  31  * Keep the natural field alignment for _each field_ within this structure if
  32  * you ever add/remove a field from this header. Packed attribute is not used
  33  * because gcc generates poor code on at least powerpc and mips. Don't ever
  34  * let gcc add padding between the structure elements.
  35  */
  36
  37 struct packet_header {
  38         /* Trace packet header */
  39         uint32_t magic;                 /*
  40                                          * Trace magic number.
  41                                          * contains endianness information.
  42                                          */
  43         uint8_t uuid[LTTNG_UST_UUID_LEN];
  44         uint32_t stream_id;
  45         uint64_t stream_instance_id;
  46
  47         struct {
  48                 /* Stream packet context */
  49                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  50                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  51                 uint64_t content_size;          /* Size of data in subbuffer */
  52                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  53                 uint64_t packet_seq_num;        /* Packet sequence number */
  54                 unsigned long events_discarded; /*
  55                                                  * Events lost in this subbuffer since
  56                                                  * the beginning of the trace.
  57                                                  * (may overflow)
  58                                                  */
  59                 uint32_t cpu_id;                /* CPU id associated with stream */
  60                 uint8_t header_end;             /* End of header */
  61         } ctx;
  62 };
  63
  64 struct lttng_client_ctx {
  65         size_t packet_context_len;
  66         size_t event_context_len;
  67         struct lttng_ust_ctx *chan_ctx;
  68         struct lttng_ust_ctx *event_ctx;
  69 };
  70
  71 static inline uint64_t lib_ring_buffer_clock_read(struct lttng_ust_lib_ring_buffer_channel *chan)
  72 {
  73         return trace_clock_read64();
  74 }
  75
  76 static inline
  77 size_t ctx_get_aligned_size(size_t offset, struct lttng_ust_ctx *ctx,
  78                 size_t ctx_len)
  79 {
  80         size_t orig_offset = offset;
  81
  82         if (caa_likely(!ctx))
  83                 return 0;
  84         offset += lttng_ust_lib_ring_buffer_align(offset, ctx->largest_align);
  85         offset += ctx_len;
  86         return offset - orig_offset;
  87 }
  88
  89 static inline
  90 void ctx_get_struct_size(struct lttng_ust_ctx *ctx, size_t *ctx_len,
  91                 enum app_ctx_mode mode)
  92 {
  93         int i;
  94         size_t offset = 0;
  95
  96         if (caa_likely(!ctx)) {
  97                 *ctx_len = 0;
  98                 return;
  99         }
 100         for (i = 0; i < ctx->nr_fields; i++) {
 101                 if (mode == APP_CTX_ENABLED) {
 102                         offset += ctx->fields[i]->get_size(ctx->fields[i], offset);
 103                 } else {
 104                         if (lttng_context_is_app(ctx->fields[i]->event_field->name)) {
 105                                 /*
 106                                  * Before UST 2.8, we cannot use the
 107                                  * application context, because we
 108                                  * cannot trust that the handler used
 109                                  * for get_size is the same used for
 110                                  * ctx_record, which would result in
 111                                  * corrupted traces when tracing
 112                                  * concurrently with application context
 113                                  * register/unregister.
 114                                  */
 115                                 offset += lttng_ust_dummy_get_size(ctx->fields[i], offset);
 116                         } else {
 117                                 offset += ctx->fields[i]->get_size(ctx->fields[i], offset);
 118                         }
 119                 }
 120         }
 121         *ctx_len = offset;
 122 }
 123
 124 static inline
 125 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 126                 struct lttng_ust_channel_buffer *chan,
 127                 struct lttng_ust_ctx *ctx,
 128                 enum app_ctx_mode mode)
 129 {
 130         int i;
 131
 132         if (caa_likely(!ctx))
 133                 return;
 134         lttng_ust_lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 135         for (i = 0; i < ctx->nr_fields; i++) {
 136                 if (mode == APP_CTX_ENABLED) {
 137                         ctx->fields[i]->record(ctx->fields[i], bufctx, chan);
 138                 } else {
 139                         if (lttng_context_is_app(ctx->fields[i]->event_field->name)) {
 140                                 /*
 141                                  * Before UST 2.8, we cannot use the
 142                                  * application context, because we
 143                                  * cannot trust that the handler used
 144                                  * for get_size is the same used for
 145                                  * ctx_record, which would result in
 146                                  * corrupted traces when tracing
 147                                  * concurrently with application context
 148                                  * register/unregister.
 149                                  */
 150                                 lttng_ust_dummy_record(ctx->fields[i], bufctx, chan);
 151                         } else {
 152                                 ctx->fields[i]->record(ctx->fields[i], bufctx, chan);
 153                         }
 154                 }
 155         }
 156 }
 157
 158 /*
 159  * record_header_size - Calculate the header size and padding necessary.
 160  * @config: ring buffer instance configuration
 161  * @chan: channel
 162  * @offset: offset in the write buffer
 163  * @pre_header_padding: padding to add before the header (output)
 164  * @ctx: reservation context
 165  *
 166  * Returns the event header size (including padding).
 167  *
 168  * The payload must itself determine its own alignment from the biggest type it
 169  * contains.
 170  */
 171 static __inline__
 172 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 173                                  struct lttng_ust_lib_ring_buffer_channel *chan,
 174                                  size_t offset,
 175                                  size_t *pre_header_padding,
 176                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 177                                  struct lttng_client_ctx *client_ctx)
 178 {
 179         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 180         size_t orig_offset = offset;
 181         size_t padding;
 182
 183         switch (lttng_chan->priv->header_type) {
 184         case 1: /* compact */
 185                 padding = lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint32_t));
 186                 offset += padding;
 187                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 188                         offset += sizeof(uint32_t);     /* id and timestamp */
 189                 } else {
 190                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 191                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 192                         /* Align extended struct on largest member */
 193                         offset += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 194                         offset += sizeof(uint32_t);     /* id */
 195                         offset += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 196                         offset += sizeof(uint64_t);     /* timestamp */
 197                 }
 198                 break;
 199         case 2: /* large */
 200                 padding = lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint16_t));
 201                 offset += padding;
 202                 offset += sizeof(uint16_t);
 203                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 204                         offset += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint32_t));
 205                         offset += sizeof(uint32_t);     /* timestamp */
 206                 } else {
 207                         /* Align extended struct on largest member */
 208                         offset += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 209                         offset += sizeof(uint32_t);     /* id */
 210                         offset += lttng_ust_lib_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 211                         offset += sizeof(uint64_t);     /* timestamp */
 212                 }
 213                 break;
 214         default:
 215                 padding = 0;
 216                 WARN_ON_ONCE(1);
 217         }
 218         offset += ctx_get_aligned_size(offset, client_ctx->chan_ctx,
 219                         client_ctx->packet_context_len);
 220         offset += ctx_get_aligned_size(offset, client_ctx->event_ctx,
 221                         client_ctx->event_context_len);
 222         *pre_header_padding = padding;
 223         return offset - orig_offset;
 224 }
 225
 226 #include "../libringbuffer/api.h"
 227 #include "lttng-rb-clients.h"
 228
 229 static
 230 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 231                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 232                                  struct lttng_client_ctx *client_ctx,
 233                                  uint32_t event_id);
 234
 235 /*
 236  * lttng_write_event_header
 237  *
 238  * Writes the event header to the offset (already aligned on 32-bits).
 239  *
 240  * @config: ring buffer instance configuration
 241  * @ctx: reservation context
 242  * @event_id: event ID
 243  */
 244 static __inline__
 245 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 246                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 247                             struct lttng_client_ctx *client_ctx,
 248                             uint32_t event_id)
 249 {
 250         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(ctx->chan);
 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                 lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_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, client_ctx->event_ctx, APP_CTX_ENABLED);
 287         lttng_ust_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
 303         switch (lttng_chan->priv->header_type) {
 304         case 1: /* compact */
 305                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 306                         uint32_t id_time = 0;
 307
 308                         bt_bitfield_write(&id_time, uint32_t,
 309                                         0,
 310                                         LTTNG_COMPACT_EVENT_BITS,
 311                                         event_id);
 312                         bt_bitfield_write(&id_time, uint32_t,
 313                                         LTTNG_COMPACT_EVENT_BITS,
 314                                         LTTNG_COMPACT_TSC_BITS,
 315                                         ctx->tsc);
 316                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 317                 } else {
 318                         uint8_t id = 0;
 319                         uint64_t timestamp = ctx->tsc;
 320
 321                         bt_bitfield_write(&id, uint8_t,
 322                                         0,
 323                                         LTTNG_COMPACT_EVENT_BITS,
 324                                         31);
 325                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 326                         /* Align extended struct on largest member */
 327                         lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 328                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 329                         lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 330                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 331                 }
 332                 break;
 333         case 2: /* large */
 334         {
 335                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 336                         uint32_t timestamp = (uint32_t) ctx->tsc;
 337                         uint16_t id = event_id;
 338
 339                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 340                         lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint32_t));
 341                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 342                 } else {
 343                         uint16_t id = 65535;
 344                         uint64_t timestamp = ctx->tsc;
 345
 346                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 347                         /* Align extended struct on largest member */
 348                         lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 349                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 350                         lttng_ust_lib_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 351                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 352                 }
 353                 break;
 354         }
 355         default:
 356                 WARN_ON_ONCE(1);
 357         }
 358         ctx_record(ctx, lttng_chan, client_ctx->chan_ctx, APP_CTX_ENABLED);
 359         ctx_record(ctx, lttng_chan, client_ctx->event_ctx, APP_CTX_ENABLED);
 360         lttng_ust_lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 361 }
 362
 363 static const struct lttng_ust_lib_ring_buffer_config client_config;
 364
 365 static uint64_t client_ring_buffer_clock_read(struct lttng_ust_lib_ring_buffer_channel *chan)
 366 {
 367         return lib_ring_buffer_clock_read(chan);
 368 }
 369
 370 static
 371 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 372                                  struct lttng_ust_lib_ring_buffer_channel *chan,
 373                                  size_t offset,
 374                                  size_t *pre_header_padding,
 375                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 376                                  void *client_ctx)
 377 {
 378         return record_header_size(config, chan, offset,
 379                                   pre_header_padding, ctx, client_ctx);
 380 }
 381
 382 /**
 383  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 384  *
 385  * Return header size without padding after the structure. Don't use packed
 386  * structure because gcc generates inefficient code on some architectures
 387  * (powerpc, mips..)
 388  */
 389 static size_t client_packet_header_size(void)
 390 {
 391         return offsetof(struct packet_header, ctx.header_end);
 392 }
 393
 394 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 395                                 unsigned int subbuf_idx,
 396                                 struct lttng_ust_shm_handle *handle)
 397 {
 398         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 399         struct packet_header *header =
 400                 (struct packet_header *)
 401                         lib_ring_buffer_offset_address(&buf->backend,
 402                                 subbuf_idx * chan->backend.subbuf_size,
 403                                 handle);
 404         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 405         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 406
 407         assert(header);
 408         if (!header)
 409                 return;
 410         header->magic = CTF_MAGIC_NUMBER;
 411         memcpy(header->uuid, lttng_chan->priv->uuid, sizeof(lttng_chan->priv->uuid));
 412         header->stream_id = lttng_chan->priv->id;
 413         header->stream_instance_id = buf->backend.cpu;
 414         header->ctx.timestamp_begin = tsc;
 415         header->ctx.timestamp_end = 0;
 416         header->ctx.content_size = ~0ULL; /* for debugging */
 417         header->ctx.packet_size = ~0ULL;
 418         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 419         header->ctx.events_discarded = 0;
 420         header->ctx.cpu_id = buf->backend.cpu;
 421 }
 422
 423 /*
 424  * offset is assumed to never be 0 here : never deliver a completely empty
 425  * subbuffer. data_size is between 1 and subbuf_size.
 426  */
 427 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 428                               unsigned int subbuf_idx, unsigned long data_size,
 429                               struct lttng_ust_shm_handle *handle)
 430 {
 431         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 432         struct packet_header *header =
 433                 (struct packet_header *)
 434                         lib_ring_buffer_offset_address(&buf->backend,
 435                                 subbuf_idx * chan->backend.subbuf_size,
 436                                 handle);
 437         unsigned long records_lost = 0;
 438
 439         assert(header);
 440         if (!header)
 441                 return;
 442         header->ctx.timestamp_end = tsc;
 443         header->ctx.content_size =
 444                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 445         header->ctx.packet_size =
 446                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 447
 448         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 449         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 450         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 451         header->ctx.events_discarded = records_lost;
 452 }
 453
 454 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 455                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 456 {
 457         return 0;
 458 }
 459
 460 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 461 {
 462 }
 463
 464 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 465                                       size_t *offset, size_t *length)
 466 {
 467         *offset = offsetof(struct packet_header, ctx.content_size);
 468         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 469 }
 470
 471 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 472                                       size_t *offset, size_t *length)
 473 {
 474         *offset = offsetof(struct packet_header, ctx.packet_size);
 475         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 476 }
 477
 478 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 479                 struct lttng_ust_shm_handle *handle)
 480 {
 481         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 482 }
 483
 484 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 485                 struct lttng_ust_lib_ring_buffer_channel *chan,
 486                 uint64_t *timestamp_begin)
 487 {
 488         struct lttng_ust_shm_handle *handle = chan->handle;
 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_lib_ring_buffer_channel *chan,
 500                 uint64_t *timestamp_end)
 501 {
 502         struct lttng_ust_shm_handle *handle = chan->handle;
 503         struct packet_header *header;
 504
 505         header = client_packet_header(buf, handle);
 506         if (!header)
 507                 return -1;
 508         *timestamp_end = header->ctx.timestamp_end;
 509         return 0;
 510 }
 511
 512 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 513                 struct lttng_ust_lib_ring_buffer_channel *chan,
 514                 uint64_t *events_discarded)
 515 {
 516         struct lttng_ust_shm_handle *handle = chan->handle;
 517         struct packet_header *header;
 518
 519         header = client_packet_header(buf, handle);
 520         if (!header)
 521                 return -1;
 522         *events_discarded = header->ctx.events_discarded;
 523         return 0;
 524 }
 525
 526 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 527                 struct lttng_ust_lib_ring_buffer_channel *chan,
 528                 uint64_t *content_size)
 529 {
 530         struct lttng_ust_shm_handle *handle = chan->handle;
 531         struct packet_header *header;
 532
 533         header = client_packet_header(buf, handle);
 534         if (!header)
 535                 return -1;
 536         *content_size = header->ctx.content_size;
 537         return 0;
 538 }
 539
 540 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 541                 struct lttng_ust_lib_ring_buffer_channel *chan,
 542                 uint64_t *packet_size)
 543 {
 544         struct lttng_ust_shm_handle *handle = chan->handle;
 545         struct packet_header *header;
 546
 547         header = client_packet_header(buf, handle);
 548         if (!header)
 549                 return -1;
 550         *packet_size = header->ctx.packet_size;
 551         return 0;
 552 }
 553
 554 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 555                 struct lttng_ust_lib_ring_buffer_channel *chan,
 556                 uint64_t *stream_id)
 557 {
 558         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 559
 560         *stream_id = lttng_chan->priv->id;
 561
 562         return 0;
 563 }
 564
 565 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 566                 struct lttng_ust_lib_ring_buffer_channel *chan,
 567                 uint64_t *ts)
 568 {
 569         *ts = client_ring_buffer_clock_read(chan);
 570
 571         return 0;
 572 }
 573
 574 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 575                 struct lttng_ust_lib_ring_buffer_channel *chan,
 576                 uint64_t *seq)
 577 {
 578         struct lttng_ust_shm_handle *handle = chan->handle;
 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_lib_ring_buffer_channel *chan,
 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->priv->rb_chan = shmp(handle, handle->chan);
 681         return lttng_chan_buf;
 682
 683 error:
 684         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 685         return NULL;
 686 }
 687
 688 static
 689 void lttng_channel_destroy(struct lttng_ust_channel_buffer *lttng_chan_buf)
 690 {
 691         channel_destroy(lttng_chan_buf->priv->rb_chan, lttng_chan_buf->priv->rb_chan->handle, 1);
 692         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 693 }
 694
 695 static
 696 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 697                       uint32_t event_id)
 698 {
 699         struct lttng_ust_stack_ctx *lttng_ctx = ctx->priv;
 700         struct lttng_ust_event_recorder *event_recorder = lttng_ctx->event_recorder;
 701         struct lttng_ust_channel_buffer *lttng_chan = event_recorder->chan;
 702         struct lttng_client_ctx client_ctx;
 703         int ret;
 704
 705         ctx->chan = lttng_chan->priv->rb_chan;
 706         client_ctx.chan_ctx = lttng_ust_rcu_dereference(lttng_chan->priv->ctx);
 707         client_ctx.event_ctx = lttng_ust_rcu_dereference(event_recorder->priv->ctx);
 708         /* Compute internal size of context structures. */
 709         ctx_get_struct_size(client_ctx.chan_ctx, &client_ctx.packet_context_len,
 710                         APP_CTX_ENABLED);
 711         ctx_get_struct_size(client_ctx.event_ctx, &client_ctx.event_context_len,
 712                         APP_CTX_ENABLED);
 713
 714         if (lib_ring_buffer_nesting_inc(&client_config) < 0)
 715                 return -EPERM;
 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_nesting_dec(&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_nesting_dec(&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 static
 767 void lttng_event_pstrcpy_pad(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 768                      const char *src, size_t len)
 769 {
 770         lib_ring_buffer_pstrcpy(&client_config, ctx, src, len, '\0');
 771 }
 772
 773 static
 774 int lttng_is_finalized(struct lttng_ust_channel_buffer *chan)
 775 {
 776         struct lttng_ust_lib_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 777
 778         return lib_ring_buffer_channel_is_finalized(rb_chan);
 779 }
 780
 781 static
 782 int lttng_is_disabled(struct lttng_ust_channel_buffer *chan)
 783 {
 784         struct lttng_ust_lib_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 785
 786         return lib_ring_buffer_channel_is_disabled(rb_chan);
 787 }
 788
 789 static
 790 int lttng_flush_buffer(struct lttng_ust_channel_buffer *chan)
 791 {
 792         struct lttng_ust_lib_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 793         struct lttng_ust_lib_ring_buffer *buf;
 794         int cpu;
 795
 796         for_each_channel_cpu(cpu, rb_chan) {
 797                 int shm_fd, wait_fd, wakeup_fd;
 798                 uint64_t memory_map_size;
 799
 800                 buf = channel_get_ring_buffer(&client_config, rb_chan,
 801                                 cpu, rb_chan->handle, &shm_fd, &wait_fd,
 802                                 &wakeup_fd, &memory_map_size);
 803                 lib_ring_buffer_switch(&client_config, buf,
 804                                 SWITCH_ACTIVE, rb_chan->handle);
 805         }
 806         return 0;
 807 }
 808
 809 static struct lttng_transport lttng_relay_transport = {
 810         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 811         .ops = {
 812                 .struct_size = sizeof(struct lttng_ust_channel_buffer_ops),
 813                 .priv = __LTTNG_COMPOUND_LITERAL(struct lttng_ust_channel_buffer_ops_private, {
 814                         .pub = &lttng_relay_transport.ops,
 815                         .channel_create = _channel_create,
 816                         .channel_destroy = lttng_channel_destroy,
 817                         .packet_avail_size = NULL,      /* Would be racy anyway */
 818                         .is_finalized = lttng_is_finalized,
 819                         .is_disabled = lttng_is_disabled,
 820                         .flush_buffer = lttng_flush_buffer,
 821                 }),
 822                 .event_reserve = lttng_event_reserve,
 823                 .event_commit = lttng_event_commit,
 824                 .event_write = lttng_event_write,
 825                 .event_strcpy = lttng_event_strcpy,
 826                 .event_pstrcpy_pad = lttng_event_pstrcpy_pad,
 827         },
 828         .client_config = &client_config,
 829 };
 830
 831 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 832 {
 833         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 834                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 835         lttng_transport_register(&lttng_relay_transport);
 836 }
 837
 838 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 839 {
 840         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 841                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 842         lttng_transport_unregister(&lttng_relay_transport);
 843 }