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

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  */
   8
   9 #include <stddef.h>
  10 #include <stdint.h>
  11 #include <lttng/ust-events.h>
  12 #include "lttng/bitfield.h"
  13 #include "clock.h"
  14 #include "lttng-tracer.h"
  15 #include "../libringbuffer/frontend_types.h"
  16
  17 #define LTTNG_COMPACT_EVENT_BITS       5
  18 #define LTTNG_COMPACT_TSC_BITS         27
  19
  20 enum app_ctx_mode {
  21         APP_CTX_DISABLED,
  22         APP_CTX_ENABLED,
  23 };
  24
  25 /*
  26  * Keep the natural field alignment for _each field_ within this structure if
  27  * you ever add/remove a field from this header. Packed attribute is not used
  28  * because gcc generates poor code on at least powerpc and mips. Don't ever
  29  * let gcc add padding between the structure elements.
  30  */
  31
  32 struct packet_header {
  33         /* Trace packet header */
  34         uint32_t magic;                 /*
  35                                          * Trace magic number.
  36                                          * contains endianness information.
  37                                          */
  38         uint8_t uuid[LTTNG_UST_UUID_LEN];
  39         uint32_t stream_id;
  40         uint64_t stream_instance_id;
  41
  42         struct {
  43                 /* Stream packet context */
  44                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  45                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  46                 uint64_t content_size;          /* Size of data in subbuffer */
  47                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  48                 uint64_t packet_seq_num;        /* Packet sequence number */
  49                 unsigned long events_discarded; /*
  50                                                  * Events lost in this subbuffer since
  51                                                  * the beginning of the trace.
  52                                                  * (may overflow)
  53                                                  */
  54                 uint32_t cpu_id;                /* CPU id associated with stream */
  55                 uint8_t header_end;             /* End of header */
  56         } ctx;
  57 };
  58
  59 struct lttng_client_ctx {
  60         size_t packet_context_len;
  61         size_t event_context_len;
  62 };
  63
  64 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  65 {
  66         return trace_clock_read64();
  67 }
  68
  69 static inline
  70 size_t ctx_get_aligned_size(size_t offset, struct lttng_ctx *ctx,
  71                 size_t ctx_len)
  72 {
  73         size_t orig_offset = offset;
  74
  75         if (caa_likely(!ctx))
  76                 return 0;
  77         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  78         offset += ctx_len;
  79         return offset - orig_offset;
  80 }
  81
  82 static inline
  83 void ctx_get_struct_size(struct lttng_ctx *ctx, size_t *ctx_len,
  84                 enum app_ctx_mode mode)
  85 {
  86         int i;
  87         size_t offset = 0;
  88
  89         if (caa_likely(!ctx)) {
  90                 *ctx_len = 0;
  91                 return;
  92         }
  93         for (i = 0; i < ctx->nr_fields; i++) {
  94                 if (mode == APP_CTX_ENABLED) {
  95                         offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
  96                 } else {
  97                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
  98                                 /*
  99                                  * Before UST 2.8, we cannot use the
 100                                  * application context, because we
 101                                  * cannot trust that the handler used
 102                                  * for get_size is the same used for
 103                                  * ctx_record, which would result in
 104                                  * corrupted traces when tracing
 105                                  * concurrently with application context
 106                                  * register/unregister.
 107                                  */
 108                                 offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
 109                         } else {
 110                                 offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 111                         }
 112                 }
 113         }
 114         *ctx_len = offset;
 115 }
 116
 117 static inline
 118 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 119                 struct lttng_channel *chan,
 120                 struct lttng_ctx *ctx,
 121                 enum app_ctx_mode mode)
 122 {
 123         int i;
 124
 125         if (caa_likely(!ctx))
 126                 return;
 127         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 128         for (i = 0; i < ctx->nr_fields; i++) {
 129                 if (mode == APP_CTX_ENABLED) {
 130                         ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 131                 } else {
 132                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 133                                 /*
 134                                  * Before UST 2.8, we cannot use the
 135                                  * application context, because we
 136                                  * cannot trust that the handler used
 137                                  * for get_size is the same used for
 138                                  * ctx_record, which would result in
 139                                  * corrupted traces when tracing
 140                                  * concurrently with application context
 141                                  * register/unregister.
 142                                  */
 143                                 lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
 144                         } else {
 145                                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 146                         }
 147                 }
 148         }
 149 }
 150
 151 /*
 152  * record_header_size - Calculate the header size and padding necessary.
 153  * @config: ring buffer instance configuration
 154  * @chan: channel
 155  * @offset: offset in the write buffer
 156  * @pre_header_padding: padding to add before the header (output)
 157  * @ctx: reservation context
 158  *
 159  * Returns the event header size (including padding).
 160  *
 161  * The payload must itself determine its own alignment from the biggest type it
 162  * contains.
 163  */
 164 static __inline__
 165 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 166                                  struct channel *chan, size_t offset,
 167                                  size_t *pre_header_padding,
 168                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 169                                  struct lttng_client_ctx *client_ctx)
 170 {
 171         struct lttng_channel *lttng_chan = channel_get_private(chan);
 172         struct lttng_event *event = ctx->priv;
 173         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 174         size_t orig_offset = offset;
 175         size_t padding;
 176
 177         switch (lttng_chan->header_type) {
 178         case 1: /* compact */
 179                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 180                 offset += padding;
 181                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 182                         offset += sizeof(uint32_t);     /* id and timestamp */
 183                 } else {
 184                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 185                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 186                         /* Align extended struct on largest member */
 187                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 188                         offset += sizeof(uint32_t);     /* id */
 189                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 190                         offset += sizeof(uint64_t);     /* timestamp */
 191                 }
 192                 break;
 193         case 2: /* large */
 194                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 195                 offset += padding;
 196                 offset += sizeof(uint16_t);
 197                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 198                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 199                         offset += sizeof(uint32_t);     /* timestamp */
 200                 } else {
 201                         /* Align extended struct on largest member */
 202                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 203                         offset += sizeof(uint32_t);     /* id */
 204                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 205                         offset += sizeof(uint64_t);     /* timestamp */
 206                 }
 207                 break;
 208         default:
 209                 padding = 0;
 210                 WARN_ON_ONCE(1);
 211         }
 212         if (lttng_ctx) {
 213                 /* 2.8+ probe ABI. */
 214                 offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 215                                 client_ctx->packet_context_len);
 216                 offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 217                                 client_ctx->event_context_len);
 218         } else {
 219                 /* Pre 2.8 probe ABI. */
 220                 offset += ctx_get_aligned_size(offset, lttng_chan->ctx,
 221                                 client_ctx->packet_context_len);
 222                 offset += ctx_get_aligned_size(offset, event->ctx,
 223                                 client_ctx->event_context_len);
 224         }
 225         *pre_header_padding = padding;
 226         return offset - orig_offset;
 227 }
 228
 229 #include "../libringbuffer/api.h"
 230 #include "lttng-rb-clients.h"
 231
 232 static
 233 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 234                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 235                                  uint32_t event_id);
 236
 237 /*
 238  * lttng_write_event_header
 239  *
 240  * Writes the event header to the offset (already aligned on 32-bits).
 241  *
 242  * @config: ring buffer instance configuration
 243  * @ctx: reservation context
 244  * @event_id: event ID
 245  */
 246 static __inline__
 247 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 248                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 249                             uint32_t event_id)
 250 {
 251         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 252         struct lttng_event *event = ctx->priv;
 253         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 254
 255         if (caa_unlikely(ctx->rflags))
 256                 goto slow_path;
 257
 258         switch (lttng_chan->header_type) {
 259         case 1: /* compact */
 260         {
 261                 uint32_t id_time = 0;
 262
 263                 bt_bitfield_write(&id_time, uint32_t,
 264                                 0,
 265                                 LTTNG_COMPACT_EVENT_BITS,
 266                                 event_id);
 267                 bt_bitfield_write(&id_time, uint32_t,
 268                                 LTTNG_COMPACT_EVENT_BITS,
 269                                 LTTNG_COMPACT_TSC_BITS,
 270                                 ctx->tsc);
 271                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 272                 break;
 273         }
 274         case 2: /* large */
 275         {
 276                 uint32_t timestamp = (uint32_t) ctx->tsc;
 277                 uint16_t id = event_id;
 278
 279                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 280                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 281                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 282                 break;
 283         }
 284         default:
 285                 WARN_ON_ONCE(1);
 286         }
 287
 288         if (lttng_ctx) {
 289                 /* 2.8+ probe ABI. */
 290                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 291                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 292         } else {
 293                 /* Pre 2.8 probe ABI. */
 294                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 295                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 296         }
 297         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 298
 299         return;
 300
 301 slow_path:
 302         lttng_write_event_header_slow(config, ctx, event_id);
 303 }
 304
 305 static
 306 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 307                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 308                                  uint32_t event_id)
 309 {
 310         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 311         struct lttng_event *event = ctx->priv;
 312         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 313
 314         switch (lttng_chan->header_type) {
 315         case 1: /* compact */
 316                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 317                         uint32_t id_time = 0;
 318
 319                         bt_bitfield_write(&id_time, uint32_t,
 320                                         0,
 321                                         LTTNG_COMPACT_EVENT_BITS,
 322                                         event_id);
 323                         bt_bitfield_write(&id_time, uint32_t,
 324                                         LTTNG_COMPACT_EVENT_BITS,
 325                                         LTTNG_COMPACT_TSC_BITS,
 326                                         ctx->tsc);
 327                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 328                 } else {
 329                         uint8_t id = 0;
 330                         uint64_t timestamp = ctx->tsc;
 331
 332                         bt_bitfield_write(&id, uint8_t,
 333                                         0,
 334                                         LTTNG_COMPACT_EVENT_BITS,
 335                                         31);
 336                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 337                         /* Align extended struct on largest member */
 338                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 339                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 340                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 341                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 342                 }
 343                 break;
 344         case 2: /* large */
 345         {
 346                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 347                         uint32_t timestamp = (uint32_t) ctx->tsc;
 348                         uint16_t id = event_id;
 349
 350                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 351                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 352                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 353                 } else {
 354                         uint16_t id = 65535;
 355                         uint64_t timestamp = ctx->tsc;
 356
 357                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 358                         /* Align extended struct on largest member */
 359                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 360                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 361                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 362                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 363                 }
 364                 break;
 365         }
 366         default:
 367                 WARN_ON_ONCE(1);
 368         }
 369         if (lttng_ctx) {
 370                 /* 2.8+ probe ABI. */
 371                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 372                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 373         } else {
 374                 /* Pre 2.8 probe ABI. */
 375                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 376                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 377         }
 378         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 379 }
 380
 381 static const struct lttng_ust_lib_ring_buffer_config client_config;
 382
 383 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 384 {
 385         return lib_ring_buffer_clock_read(chan);
 386 }
 387
 388 static
 389 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 390                                  struct channel *chan, size_t offset,
 391                                  size_t *pre_header_padding,
 392                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 393                                  void *client_ctx)
 394 {
 395         return record_header_size(config, chan, offset,
 396                                   pre_header_padding, ctx, client_ctx);
 397 }
 398
 399 /**
 400  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 401  *
 402  * Return header size without padding after the structure. Don't use packed
 403  * structure because gcc generates inefficient code on some architectures
 404  * (powerpc, mips..)
 405  */
 406 static size_t client_packet_header_size(void)
 407 {
 408         return offsetof(struct packet_header, ctx.header_end);
 409 }
 410
 411 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 412                                 unsigned int subbuf_idx,
 413                                 struct lttng_ust_shm_handle *handle)
 414 {
 415         struct channel *chan = shmp(handle, buf->backend.chan);
 416         struct packet_header *header =
 417                 (struct packet_header *)
 418                         lib_ring_buffer_offset_address(&buf->backend,
 419                                 subbuf_idx * chan->backend.subbuf_size,
 420                                 handle);
 421         struct lttng_channel *lttng_chan = channel_get_private(chan);
 422         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 423
 424         assert(header);
 425         if (!header)
 426                 return;
 427         header->magic = CTF_MAGIC_NUMBER;
 428         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 429         header->stream_id = lttng_chan->id;
 430         header->stream_instance_id = buf->backend.cpu;
 431         header->ctx.timestamp_begin = tsc;
 432         header->ctx.timestamp_end = 0;
 433         header->ctx.content_size = ~0ULL; /* for debugging */
 434         header->ctx.packet_size = ~0ULL;
 435         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 436         header->ctx.events_discarded = 0;
 437         header->ctx.cpu_id = buf->backend.cpu;
 438 }
 439
 440 /*
 441  * offset is assumed to never be 0 here : never deliver a completely empty
 442  * subbuffer. data_size is between 1 and subbuf_size.
 443  */
 444 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 445                               unsigned int subbuf_idx, unsigned long data_size,
 446                               struct lttng_ust_shm_handle *handle)
 447 {
 448         struct channel *chan = shmp(handle, buf->backend.chan);
 449         struct packet_header *header =
 450                 (struct packet_header *)
 451                         lib_ring_buffer_offset_address(&buf->backend,
 452                                 subbuf_idx * chan->backend.subbuf_size,
 453                                 handle);
 454         unsigned long records_lost = 0;
 455
 456         assert(header);
 457         if (!header)
 458                 return;
 459         header->ctx.timestamp_end = tsc;
 460         header->ctx.content_size =
 461                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 462         header->ctx.packet_size =
 463                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 464
 465         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 466         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 467         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 468         header->ctx.events_discarded = records_lost;
 469 }
 470
 471 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 472                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 473 {
 474         return 0;
 475 }
 476
 477 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 478 {
 479 }
 480
 481 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 482                                       size_t *offset, size_t *length)
 483 {
 484         *offset = offsetof(struct packet_header, ctx.content_size);
 485         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 486 }
 487
 488 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 489                                       size_t *offset, size_t *length)
 490 {
 491         *offset = offsetof(struct packet_header, ctx.packet_size);
 492         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 493 }
 494
 495 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 496                 struct lttng_ust_shm_handle *handle)
 497 {
 498         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 499 }
 500
 501 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 502                 struct lttng_ust_shm_handle *handle,
 503                 uint64_t *timestamp_begin)
 504 {
 505         struct packet_header *header;
 506
 507         header = client_packet_header(buf, handle);
 508         if (!header)
 509                 return -1;
 510         *timestamp_begin = header->ctx.timestamp_begin;
 511         return 0;
 512 }
 513
 514 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 515                 struct lttng_ust_shm_handle *handle,
 516                 uint64_t *timestamp_end)
 517 {
 518         struct packet_header *header;
 519
 520         header = client_packet_header(buf, handle);
 521         if (!header)
 522                 return -1;
 523         *timestamp_end = header->ctx.timestamp_end;
 524         return 0;
 525 }
 526
 527 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 528                 struct lttng_ust_shm_handle *handle,
 529                 uint64_t *events_discarded)
 530 {
 531         struct packet_header *header;
 532
 533         header = client_packet_header(buf, handle);
 534         if (!header)
 535                 return -1;
 536         *events_discarded = header->ctx.events_discarded;
 537         return 0;
 538 }
 539
 540 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 541                 struct lttng_ust_shm_handle *handle,
 542                 uint64_t *content_size)
 543 {
 544         struct packet_header *header;
 545
 546         header = client_packet_header(buf, handle);
 547         if (!header)
 548                 return -1;
 549         *content_size = header->ctx.content_size;
 550         return 0;
 551 }
 552
 553 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 554                 struct lttng_ust_shm_handle *handle,
 555                 uint64_t *packet_size)
 556 {
 557         struct packet_header *header;
 558
 559         header = client_packet_header(buf, handle);
 560         if (!header)
 561                 return -1;
 562         *packet_size = header->ctx.packet_size;
 563         return 0;
 564 }
 565
 566 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 567                 struct lttng_ust_shm_handle *handle,
 568                 uint64_t *stream_id)
 569 {
 570         struct channel *chan = shmp(handle, buf->backend.chan);
 571         struct lttng_channel *lttng_chan = channel_get_private(chan);
 572
 573         *stream_id = lttng_chan->id;
 574
 575         return 0;
 576 }
 577
 578 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 579                 struct lttng_ust_shm_handle *handle,
 580                 uint64_t *ts)
 581 {
 582         struct channel *chan;
 583
 584         chan = shmp(handle, handle->chan);
 585         *ts = client_ring_buffer_clock_read(chan);
 586
 587         return 0;
 588 }
 589
 590 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 591                 struct lttng_ust_shm_handle *handle,
 592                 uint64_t *seq)
 593 {
 594         struct packet_header *header;
 595
 596         header = client_packet_header(buf, handle);
 597         if (!header)
 598                 return -1;
 599         *seq = header->ctx.packet_seq_num;
 600         return 0;
 601 }
 602
 603 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 604                 struct lttng_ust_shm_handle *handle,
 605                 uint64_t *id)
 606 {
 607         *id = buf->backend.cpu;
 608
 609         return 0;
 610 }
 611
 612 static const
 613 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 614         .parent = {
 615                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 616                 .record_header_size = client_record_header_size,
 617                 .subbuffer_header_size = client_packet_header_size,
 618                 .buffer_begin = client_buffer_begin,
 619                 .buffer_end = client_buffer_end,
 620                 .buffer_create = client_buffer_create,
 621                 .buffer_finalize = client_buffer_finalize,
 622                 .content_size_field = client_content_size_field,
 623                 .packet_size_field = client_packet_size_field,
 624         },
 625         .timestamp_begin = client_timestamp_begin,
 626         .timestamp_end = client_timestamp_end,
 627         .events_discarded = client_events_discarded,
 628         .content_size = client_content_size,
 629         .packet_size = client_packet_size,
 630         .stream_id = client_stream_id,
 631         .current_timestamp = client_current_timestamp,
 632         .sequence_number = client_sequence_number,
 633         .instance_id = client_instance_id,
 634 };
 635
 636 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 637         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 638         .cb.record_header_size = client_record_header_size,
 639         .cb.subbuffer_header_size = client_packet_header_size,
 640         .cb.buffer_begin = client_buffer_begin,
 641         .cb.buffer_end = client_buffer_end,
 642         .cb.buffer_create = client_buffer_create,
 643         .cb.buffer_finalize = client_buffer_finalize,
 644         .cb.content_size_field = client_content_size_field,
 645         .cb.packet_size_field = client_packet_size_field,
 646
 647         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 648         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 649         .sync = RING_BUFFER_SYNC_GLOBAL,
 650         .mode = RING_BUFFER_MODE_TEMPLATE,
 651         .backend = RING_BUFFER_PAGE,
 652         .output = RING_BUFFER_MMAP,
 653         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 654         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 655         .wakeup = LTTNG_CLIENT_WAKEUP,
 656         .client_type = LTTNG_CLIENT_TYPE,
 657
 658         .cb_ptr = &client_cb.parent,
 659 };
 660
 661 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 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 }