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