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 "context-internal.h"
  17 #include "lttng-tracer.h"
  18 #include "../libringbuffer/frontend_types.h"
  19
  20 #define LTTNG_COMPACT_EVENT_BITS       5
  21 #define LTTNG_COMPACT_TSC_BITS         27
  22
  23 enum app_ctx_mode {
  24         APP_CTX_DISABLED,
  25         APP_CTX_ENABLED,
  26 };
  27
  28 /*
  29  * Keep the natural field alignment for _each field_ within this structure if
  30  * you ever add/remove a field from this header. Packed attribute is not used
  31  * because gcc generates poor code on at least powerpc and mips. Don't ever
  32  * let gcc add padding between the structure elements.
  33  */
  34
  35 struct packet_header {
  36         /* Trace packet header */
  37         uint32_t magic;                 /*
  38                                          * Trace magic number.
  39                                          * contains endianness information.
  40                                          */
  41         uint8_t uuid[LTTNG_UST_UUID_LEN];
  42         uint32_t stream_id;
  43         uint64_t stream_instance_id;
  44
  45         struct {
  46                 /* Stream packet context */
  47                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  48                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  49                 uint64_t content_size;          /* Size of data in subbuffer */
  50                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  51                 uint64_t packet_seq_num;        /* Packet sequence number */
  52                 unsigned long events_discarded; /*
  53                                                  * Events lost in this subbuffer since
  54                                                  * the beginning of the trace.
  55                                                  * (may overflow)
  56                                                  */
  57                 uint32_t cpu_id;                /* CPU id associated with stream */
  58                 uint8_t header_end;             /* End of header */
  59         } ctx;
  60 };
  61
  62 struct lttng_client_ctx {
  63         size_t packet_context_len;
  64         size_t event_context_len;
  65 };
  66
  67 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  68 {
  69         return trace_clock_read64();
  70 }
  71
  72 static inline
  73 size_t ctx_get_aligned_size(size_t offset, struct lttng_ctx *ctx,
  74                 size_t ctx_len)
  75 {
  76         size_t orig_offset = offset;
  77
  78         if (caa_likely(!ctx))
  79                 return 0;
  80         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  81         offset += ctx_len;
  82         return offset - orig_offset;
  83 }
  84
  85 static inline
  86 void ctx_get_struct_size(struct lttng_ctx *ctx, size_t *ctx_len,
  87                 enum app_ctx_mode mode)
  88 {
  89         int i;
  90         size_t offset = 0;
  91
  92         if (caa_likely(!ctx)) {
  93                 *ctx_len = 0;
  94                 return;
  95         }
  96         for (i = 0; i < ctx->nr_fields; i++) {
  97                 if (mode == APP_CTX_ENABLED) {
  98                         offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
  99                 } else {
 100                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 101                                 /*
 102                                  * Before UST 2.8, we cannot use the
 103                                  * application context, because we
 104                                  * cannot trust that the handler used
 105                                  * for get_size is the same used for
 106                                  * ctx_record, which would result in
 107                                  * corrupted traces when tracing
 108                                  * concurrently with application context
 109                                  * register/unregister.
 110                                  */
 111                                 offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
 112                         } else {
 113                                 offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 114                         }
 115                 }
 116         }
 117         *ctx_len = offset;
 118 }
 119
 120 static inline
 121 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 122                 struct lttng_channel *chan,
 123                 struct lttng_ctx *ctx,
 124                 enum app_ctx_mode mode)
 125 {
 126         int i;
 127
 128         if (caa_likely(!ctx))
 129                 return;
 130         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 131         for (i = 0; i < ctx->nr_fields; i++) {
 132                 if (mode == APP_CTX_ENABLED) {
 133                         ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 134                 } else {
 135                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 136                                 /*
 137                                  * Before UST 2.8, we cannot use the
 138                                  * application context, because we
 139                                  * cannot trust that the handler used
 140                                  * for get_size is the same used for
 141                                  * ctx_record, which would result in
 142                                  * corrupted traces when tracing
 143                                  * concurrently with application context
 144                                  * register/unregister.
 145                                  */
 146                                 lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
 147                         } else {
 148                                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 149                         }
 150                 }
 151         }
 152 }
 153
 154 /*
 155  * record_header_size - Calculate the header size and padding necessary.
 156  * @config: ring buffer instance configuration
 157  * @chan: channel
 158  * @offset: offset in the write buffer
 159  * @pre_header_padding: padding to add before the header (output)
 160  * @ctx: reservation context
 161  *
 162  * Returns the event header size (including padding).
 163  *
 164  * The payload must itself determine its own alignment from the biggest type it
 165  * contains.
 166  */
 167 static __inline__
 168 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 169                                  struct channel *chan, size_t offset,
 170                                  size_t *pre_header_padding,
 171                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 172                                  struct lttng_client_ctx *client_ctx)
 173 {
 174         struct lttng_channel *lttng_chan = channel_get_private(chan);
 175         struct lttng_event *event = ctx->priv;
 176         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 177         size_t orig_offset = offset;
 178         size_t padding;
 179
 180         switch (lttng_chan->header_type) {
 181         case 1: /* compact */
 182                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 183                 offset += padding;
 184                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 185                         offset += sizeof(uint32_t);     /* id and timestamp */
 186                 } else {
 187                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 188                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 189                         /* Align extended struct on largest member */
 190                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 191                         offset += sizeof(uint32_t);     /* id */
 192                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 193                         offset += sizeof(uint64_t);     /* timestamp */
 194                 }
 195                 break;
 196         case 2: /* large */
 197                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 198                 offset += padding;
 199                 offset += sizeof(uint16_t);
 200                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 201                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 202                         offset += sizeof(uint32_t);     /* timestamp */
 203                 } else {
 204                         /* Align extended struct on largest member */
 205                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 206                         offset += sizeof(uint32_t);     /* id */
 207                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 208                         offset += sizeof(uint64_t);     /* timestamp */
 209                 }
 210                 break;
 211         default:
 212                 padding = 0;
 213                 WARN_ON_ONCE(1);
 214         }
 215         if (lttng_ctx) {
 216                 /* 2.8+ probe ABI. */
 217                 offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 218                                 client_ctx->packet_context_len);
 219                 offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 220                                 client_ctx->event_context_len);
 221         } else {
 222                 /* Pre 2.8 probe ABI. */
 223                 offset += ctx_get_aligned_size(offset, lttng_chan->ctx,
 224                                 client_ctx->packet_context_len);
 225                 offset += ctx_get_aligned_size(offset, event->ctx,
 226                                 client_ctx->event_context_len);
 227         }
 228         *pre_header_padding = padding;
 229         return offset - orig_offset;
 230 }
 231
 232 #include "../libringbuffer/api.h"
 233 #include "lttng-rb-clients.h"
 234
 235 static
 236 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 237                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 238                                  uint32_t event_id);
 239
 240 /*
 241  * lttng_write_event_header
 242  *
 243  * Writes the event header to the offset (already aligned on 32-bits).
 244  *
 245  * @config: ring buffer instance configuration
 246  * @ctx: reservation context
 247  * @event_id: event ID
 248  */
 249 static __inline__
 250 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 251                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 252                             uint32_t event_id)
 253 {
 254         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 255         struct lttng_event *event = ctx->priv;
 256         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 257
 258         if (caa_unlikely(ctx->rflags))
 259                 goto slow_path;
 260
 261         switch (lttng_chan->header_type) {
 262         case 1: /* compact */
 263         {
 264                 uint32_t id_time = 0;
 265
 266                 bt_bitfield_write(&id_time, uint32_t,
 267                                 0,
 268                                 LTTNG_COMPACT_EVENT_BITS,
 269                                 event_id);
 270                 bt_bitfield_write(&id_time, uint32_t,
 271                                 LTTNG_COMPACT_EVENT_BITS,
 272                                 LTTNG_COMPACT_TSC_BITS,
 273                                 ctx->tsc);
 274                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 275                 break;
 276         }
 277         case 2: /* large */
 278         {
 279                 uint32_t timestamp = (uint32_t) ctx->tsc;
 280                 uint16_t id = event_id;
 281
 282                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 283                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 284                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 285                 break;
 286         }
 287         default:
 288                 WARN_ON_ONCE(1);
 289         }
 290
 291         if (lttng_ctx) {
 292                 /* 2.8+ probe ABI. */
 293                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 294                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 295         } else {
 296                 /* Pre 2.8 probe ABI. */
 297                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 298                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 299         }
 300         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 301
 302         return;
 303
 304 slow_path:
 305         lttng_write_event_header_slow(config, ctx, event_id);
 306 }
 307
 308 static
 309 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 310                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 311                                  uint32_t event_id)
 312 {
 313         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 314         struct lttng_event *event = ctx->priv;
 315         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 316
 317         switch (lttng_chan->header_type) {
 318         case 1: /* compact */
 319                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 320                         uint32_t id_time = 0;
 321
 322                         bt_bitfield_write(&id_time, uint32_t,
 323                                         0,
 324                                         LTTNG_COMPACT_EVENT_BITS,
 325                                         event_id);
 326                         bt_bitfield_write(&id_time, uint32_t,
 327                                         LTTNG_COMPACT_EVENT_BITS,
 328                                         LTTNG_COMPACT_TSC_BITS,
 329                                         ctx->tsc);
 330                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 331                 } else {
 332                         uint8_t id = 0;
 333                         uint64_t timestamp = ctx->tsc;
 334
 335                         bt_bitfield_write(&id, uint8_t,
 336                                         0,
 337                                         LTTNG_COMPACT_EVENT_BITS,
 338                                         31);
 339                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 340                         /* Align extended struct on largest member */
 341                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 342                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 343                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 344                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 345                 }
 346                 break;
 347         case 2: /* large */
 348         {
 349                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 350                         uint32_t timestamp = (uint32_t) ctx->tsc;
 351                         uint16_t id = event_id;
 352
 353                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 354                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 355                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 356                 } else {
 357                         uint16_t id = 65535;
 358                         uint64_t timestamp = ctx->tsc;
 359
 360                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 361                         /* Align extended struct on largest member */
 362                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 363                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 364                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 365                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 366                 }
 367                 break;
 368         }
 369         default:
 370                 WARN_ON_ONCE(1);
 371         }
 372         if (lttng_ctx) {
 373                 /* 2.8+ probe ABI. */
 374                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 375                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 376         } else {
 377                 /* Pre 2.8 probe ABI. */
 378                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 379                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 380         }
 381         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 382 }
 383
 384 static const struct lttng_ust_lib_ring_buffer_config client_config;
 385
 386 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 387 {
 388         return lib_ring_buffer_clock_read(chan);
 389 }
 390
 391 static
 392 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 393                                  struct channel *chan, size_t offset,
 394                                  size_t *pre_header_padding,
 395                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 396                                  void *client_ctx)
 397 {
 398         return record_header_size(config, chan, offset,
 399                                   pre_header_padding, ctx, client_ctx);
 400 }
 401
 402 /**
 403  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 404  *
 405  * Return header size without padding after the structure. Don't use packed
 406  * structure because gcc generates inefficient code on some architectures
 407  * (powerpc, mips..)
 408  */
 409 static size_t client_packet_header_size(void)
 410 {
 411         return offsetof(struct packet_header, ctx.header_end);
 412 }
 413
 414 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 415                                 unsigned int subbuf_idx,
 416                                 struct lttng_ust_shm_handle *handle)
 417 {
 418         struct channel *chan = shmp(handle, buf->backend.chan);
 419         struct packet_header *header =
 420                 (struct packet_header *)
 421                         lib_ring_buffer_offset_address(&buf->backend,
 422                                 subbuf_idx * chan->backend.subbuf_size,
 423                                 handle);
 424         struct lttng_channel *lttng_chan = channel_get_private(chan);
 425         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 426
 427         assert(header);
 428         if (!header)
 429                 return;
 430         header->magic = CTF_MAGIC_NUMBER;
 431         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 432         header->stream_id = lttng_chan->id;
 433         header->stream_instance_id = buf->backend.cpu;
 434         header->ctx.timestamp_begin = tsc;
 435         header->ctx.timestamp_end = 0;
 436         header->ctx.content_size = ~0ULL; /* for debugging */
 437         header->ctx.packet_size = ~0ULL;
 438         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 439         header->ctx.events_discarded = 0;
 440         header->ctx.cpu_id = buf->backend.cpu;
 441 }
 442
 443 /*
 444  * offset is assumed to never be 0 here : never deliver a completely empty
 445  * subbuffer. data_size is between 1 and subbuf_size.
 446  */
 447 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 448                               unsigned int subbuf_idx, unsigned long data_size,
 449                               struct lttng_ust_shm_handle *handle)
 450 {
 451         struct channel *chan = shmp(handle, buf->backend.chan);
 452         struct packet_header *header =
 453                 (struct packet_header *)
 454                         lib_ring_buffer_offset_address(&buf->backend,
 455                                 subbuf_idx * chan->backend.subbuf_size,
 456                                 handle);
 457         unsigned long records_lost = 0;
 458
 459         assert(header);
 460         if (!header)
 461                 return;
 462         header->ctx.timestamp_end = tsc;
 463         header->ctx.content_size =
 464                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 465         header->ctx.packet_size =
 466                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 467
 468         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 469         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 470         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 471         header->ctx.events_discarded = records_lost;
 472 }
 473
 474 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 475                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 476 {
 477         return 0;
 478 }
 479
 480 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 481 {
 482 }
 483
 484 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 485                                       size_t *offset, size_t *length)
 486 {
 487         *offset = offsetof(struct packet_header, ctx.content_size);
 488         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 489 }
 490
 491 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 492                                       size_t *offset, size_t *length)
 493 {
 494         *offset = offsetof(struct packet_header, ctx.packet_size);
 495         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 496 }
 497
 498 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 499                 struct lttng_ust_shm_handle *handle)
 500 {
 501         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 502 }
 503
 504 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 505                 struct lttng_ust_shm_handle *handle,
 506                 uint64_t *timestamp_begin)
 507 {
 508         struct packet_header *header;
 509
 510         header = client_packet_header(buf, handle);
 511         if (!header)
 512                 return -1;
 513         *timestamp_begin = header->ctx.timestamp_begin;
 514         return 0;
 515 }
 516
 517 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 518                 struct lttng_ust_shm_handle *handle,
 519                 uint64_t *timestamp_end)
 520 {
 521         struct packet_header *header;
 522
 523         header = client_packet_header(buf, handle);
 524         if (!header)
 525                 return -1;
 526         *timestamp_end = header->ctx.timestamp_end;
 527         return 0;
 528 }
 529
 530 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 531                 struct lttng_ust_shm_handle *handle,
 532                 uint64_t *events_discarded)
 533 {
 534         struct packet_header *header;
 535
 536         header = client_packet_header(buf, handle);
 537         if (!header)
 538                 return -1;
 539         *events_discarded = header->ctx.events_discarded;
 540         return 0;
 541 }
 542
 543 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 544                 struct lttng_ust_shm_handle *handle,
 545                 uint64_t *content_size)
 546 {
 547         struct packet_header *header;
 548
 549         header = client_packet_header(buf, handle);
 550         if (!header)
 551                 return -1;
 552         *content_size = header->ctx.content_size;
 553         return 0;
 554 }
 555
 556 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 557                 struct lttng_ust_shm_handle *handle,
 558                 uint64_t *packet_size)
 559 {
 560         struct packet_header *header;
 561
 562         header = client_packet_header(buf, handle);
 563         if (!header)
 564                 return -1;
 565         *packet_size = header->ctx.packet_size;
 566         return 0;
 567 }
 568
 569 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 570                 struct lttng_ust_shm_handle *handle,
 571                 uint64_t *stream_id)
 572 {
 573         struct channel *chan = shmp(handle, buf->backend.chan);
 574         struct lttng_channel *lttng_chan = channel_get_private(chan);
 575
 576         *stream_id = lttng_chan->id;
 577
 578         return 0;
 579 }
 580
 581 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 582                 struct lttng_ust_shm_handle *handle,
 583                 uint64_t *ts)
 584 {
 585         struct channel *chan;
 586
 587         chan = shmp(handle, handle->chan);
 588         *ts = client_ring_buffer_clock_read(chan);
 589
 590         return 0;
 591 }
 592
 593 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 594                 struct lttng_ust_shm_handle *handle,
 595                 uint64_t *seq)
 596 {
 597         struct packet_header *header;
 598
 599         header = client_packet_header(buf, handle);
 600         if (!header)
 601                 return -1;
 602         *seq = header->ctx.packet_seq_num;
 603         return 0;
 604 }
 605
 606 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 607                 struct lttng_ust_shm_handle *handle,
 608                 uint64_t *id)
 609 {
 610         *id = buf->backend.cpu;
 611
 612         return 0;
 613 }
 614
 615 static const
 616 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 617         .parent = {
 618                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 619                 .record_header_size = client_record_header_size,
 620                 .subbuffer_header_size = client_packet_header_size,
 621                 .buffer_begin = client_buffer_begin,
 622                 .buffer_end = client_buffer_end,
 623                 .buffer_create = client_buffer_create,
 624                 .buffer_finalize = client_buffer_finalize,
 625                 .content_size_field = client_content_size_field,
 626                 .packet_size_field = client_packet_size_field,
 627         },
 628         .timestamp_begin = client_timestamp_begin,
 629         .timestamp_end = client_timestamp_end,
 630         .events_discarded = client_events_discarded,
 631         .content_size = client_content_size,
 632         .packet_size = client_packet_size,
 633         .stream_id = client_stream_id,
 634         .current_timestamp = client_current_timestamp,
 635         .sequence_number = client_sequence_number,
 636         .instance_id = client_instance_id,
 637 };
 638
 639 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 640         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 641         .cb.record_header_size = client_record_header_size,
 642         .cb.subbuffer_header_size = client_packet_header_size,
 643         .cb.buffer_begin = client_buffer_begin,
 644         .cb.buffer_end = client_buffer_end,
 645         .cb.buffer_create = client_buffer_create,
 646         .cb.buffer_finalize = client_buffer_finalize,
 647         .cb.content_size_field = client_content_size_field,
 648         .cb.packet_size_field = client_packet_size_field,
 649
 650         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 651         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 652         .sync = RING_BUFFER_SYNC_GLOBAL,
 653         .mode = RING_BUFFER_MODE_TEMPLATE,
 654         .backend = RING_BUFFER_PAGE,
 655         .output = RING_BUFFER_MMAP,
 656         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 657         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 658         .wakeup = LTTNG_CLIENT_WAKEUP,
 659         .client_type = LTTNG_CLIENT_TYPE,
 660
 661         .cb_ptr = &client_cb.parent,
 662 };
 663
 664 static
 665 struct lttng_channel *_channel_create(const char *name,
 666                                 void *buf_addr,
 667                                 size_t subbuf_size, size_t num_subbuf,
 668                                 unsigned int switch_timer_interval,
 669                                 unsigned int read_timer_interval,
 670                                 unsigned char *uuid,
 671                                 uint32_t chan_id,
 672                                 const int *stream_fds, int nr_stream_fds,
 673                                 int64_t blocking_timeout)
 674 {
 675         struct lttng_channel chan_priv_init;
 676         struct lttng_ust_shm_handle *handle;
 677         struct lttng_channel *lttng_chan;
 678         void *priv;
 679
 680         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 681         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 682         chan_priv_init.id = chan_id;
 683         handle = channel_create(&client_config, name,
 684                         &priv, __alignof__(struct lttng_channel),
 685                         sizeof(struct lttng_channel),
 686                         &chan_priv_init,
 687                         buf_addr, subbuf_size, num_subbuf,
 688                         switch_timer_interval, read_timer_interval,
 689                         stream_fds, nr_stream_fds, blocking_timeout);
 690         if (!handle)
 691                 return NULL;
 692         lttng_chan = priv;
 693         lttng_chan->handle = handle;
 694         lttng_chan->chan = shmp(handle, handle->chan);
 695         return lttng_chan;
 696 }
 697
 698 static
 699 void lttng_channel_destroy(struct lttng_channel *chan)
 700 {
 701         channel_destroy(chan->chan, chan->handle, 1);
 702 }
 703
 704 static
 705 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 706                       uint32_t event_id)
 707 {
 708         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 709         struct lttng_event *event = ctx->priv;
 710         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 711         struct lttng_client_ctx client_ctx;
 712         int ret, cpu;
 713
 714         /* Compute internal size of context structures. */
 715
 716         if (lttng_ctx) {
 717                 /* 2.8+ probe ABI. */
 718                 ctx_get_struct_size(lttng_ctx->chan_ctx, &client_ctx.packet_context_len,
 719                                 APP_CTX_ENABLED);
 720                 ctx_get_struct_size(lttng_ctx->event_ctx, &client_ctx.event_context_len,
 721                                 APP_CTX_ENABLED);
 722         } else {
 723                 /* Pre 2.8 probe ABI. */
 724                 ctx_get_struct_size(lttng_chan->ctx, &client_ctx.packet_context_len,
 725                                 APP_CTX_DISABLED);
 726                 ctx_get_struct_size(event->ctx, &client_ctx.event_context_len,
 727                                 APP_CTX_DISABLED);
 728         }
 729
 730         cpu = lib_ring_buffer_get_cpu(&client_config);
 731         if (cpu < 0)
 732                 return -EPERM;
 733         ctx->cpu = cpu;
 734
 735         switch (lttng_chan->header_type) {
 736         case 1: /* compact */
 737                 if (event_id > 30)
 738                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 739                 break;
 740         case 2: /* large */
 741                 if (event_id > 65534)
 742                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 743                 break;
 744         default:
 745                 WARN_ON_ONCE(1);
 746         }
 747
 748         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 749         if (caa_unlikely(ret))
 750                 goto put;
 751         if (caa_likely(ctx->ctx_len
 752                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 753                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 754                                 &ctx->backend_pages)) {
 755                         ret = -EPERM;
 756                         goto put;
 757                 }
 758         }
 759         lttng_write_event_header(&client_config, ctx, event_id);
 760         return 0;
 761 put:
 762         lib_ring_buffer_put_cpu(&client_config);
 763         return ret;
 764 }
 765
 766 static
 767 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 768 {
 769         lib_ring_buffer_commit(&client_config, ctx);
 770         lib_ring_buffer_put_cpu(&client_config);
 771 }
 772
 773 static
 774 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 775                      size_t len)
 776 {
 777         lib_ring_buffer_write(&client_config, ctx, src, len);
 778 }
 779
 780 static
 781 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 782                      size_t len)
 783 {
 784         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 785 }
 786
 787 #if 0
 788 static
 789 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 790 {
 791         return &chan->read_wait;
 792 }
 793
 794 static
 795 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 796 {
 797         return &chan->hp_wait;
 798 }
 799 #endif //0
 800
 801 static
 802 int lttng_is_finalized(struct channel *chan)
 803 {
 804         return lib_ring_buffer_channel_is_finalized(chan);
 805 }
 806
 807 static
 808 int lttng_is_disabled(struct channel *chan)
 809 {
 810         return lib_ring_buffer_channel_is_disabled(chan);
 811 }
 812
 813 static
 814 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 815 {
 816         struct lttng_ust_lib_ring_buffer *buf;
 817         int cpu;
 818
 819         for_each_channel_cpu(cpu, chan) {
 820                 int shm_fd, wait_fd, wakeup_fd;
 821                 uint64_t memory_map_size;
 822
 823                 buf = channel_get_ring_buffer(&client_config, chan,
 824                                 cpu, handle, &shm_fd, &wait_fd,
 825                                 &wakeup_fd, &memory_map_size);
 826                 lib_ring_buffer_switch(&client_config, buf,
 827                                 SWITCH_ACTIVE, handle);
 828         }
 829         return 0;
 830 }
 831
 832 static struct lttng_transport lttng_relay_transport = {
 833         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 834         .ops = {
 835                 .channel_create = _channel_create,
 836                 .channel_destroy = lttng_channel_destroy,
 837                 .event_reserve = lttng_event_reserve,
 838                 .event_commit = lttng_event_commit,
 839                 .event_write = lttng_event_write,
 840                 .packet_avail_size = NULL,      /* Would be racy anyway */
 841                 .is_finalized = lttng_is_finalized,
 842                 .is_disabled = lttng_is_disabled,
 843                 .flush_buffer = lttng_flush_buffer,
 844                 .event_strcpy = lttng_event_strcpy,
 845         },
 846         .client_config = &client_config,
 847 };
 848
 849 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 850 {
 851         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 852                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 853         lttng_transport_register(&lttng_relay_transport);
 854 }
 855
 856 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 857 {
 858         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 859                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 860         lttng_transport_unregister(&lttng_relay_transport);
 861 }