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 lttng_ust_lib_ring_buffer_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_ust_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_ust_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_ust_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 lttng_ust_lib_ring_buffer_channel *chan,
 170                                  size_t offset,
 171                                  size_t *pre_header_padding,
 172                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 173                                  struct lttng_client_ctx *client_ctx)
 174 {
 175         struct lttng_channel *lttng_chan = channel_get_private(chan);
 176         struct lttng_ust_stack_ctx *lttng_ctx = ctx->priv;
 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         offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 216                         client_ctx->packet_context_len);
 217         offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 218                         client_ctx->event_context_len);
 219         *pre_header_padding = padding;
 220         return offset - orig_offset;
 221 }
 222
 223 #include "../libringbuffer/api.h"
 224 #include "lttng-rb-clients.h"
 225
 226 static
 227 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 228                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 229                                  uint32_t event_id);
 230
 231 /*
 232  * lttng_write_event_header
 233  *
 234  * Writes the event header to the offset (already aligned on 32-bits).
 235  *
 236  * @config: ring buffer instance configuration
 237  * @ctx: reservation context
 238  * @event_id: event ID
 239  */
 240 static __inline__
 241 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 242                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 243                             uint32_t event_id)
 244 {
 245         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 246         struct lttng_ust_stack_ctx *lttng_ctx = ctx->priv;
 247
 248         if (caa_unlikely(ctx->rflags))
 249                 goto slow_path;
 250
 251         switch (lttng_chan->header_type) {
 252         case 1: /* compact */
 253         {
 254                 uint32_t id_time = 0;
 255
 256                 bt_bitfield_write(&id_time, uint32_t,
 257                                 0,
 258                                 LTTNG_COMPACT_EVENT_BITS,
 259                                 event_id);
 260                 bt_bitfield_write(&id_time, uint32_t,
 261                                 LTTNG_COMPACT_EVENT_BITS,
 262                                 LTTNG_COMPACT_TSC_BITS,
 263                                 ctx->tsc);
 264                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 265                 break;
 266         }
 267         case 2: /* large */
 268         {
 269                 uint32_t timestamp = (uint32_t) ctx->tsc;
 270                 uint16_t id = event_id;
 271
 272                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 273                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 274                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 275                 break;
 276         }
 277         default:
 278                 WARN_ON_ONCE(1);
 279         }
 280
 281         ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 282         ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 283         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 284
 285         return;
 286
 287 slow_path:
 288         lttng_write_event_header_slow(config, ctx, event_id);
 289 }
 290
 291 static
 292 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 293                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 294                                  uint32_t event_id)
 295 {
 296         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 297         struct lttng_ust_stack_ctx *lttng_ctx = ctx->priv;
 298
 299         switch (lttng_chan->header_type) {
 300         case 1: /* compact */
 301                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 302                         uint32_t id_time = 0;
 303
 304                         bt_bitfield_write(&id_time, uint32_t,
 305                                         0,
 306                                         LTTNG_COMPACT_EVENT_BITS,
 307                                         event_id);
 308                         bt_bitfield_write(&id_time, uint32_t,
 309                                         LTTNG_COMPACT_EVENT_BITS,
 310                                         LTTNG_COMPACT_TSC_BITS,
 311                                         ctx->tsc);
 312                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 313                 } else {
 314                         uint8_t id = 0;
 315                         uint64_t timestamp = ctx->tsc;
 316
 317                         bt_bitfield_write(&id, uint8_t,
 318                                         0,
 319                                         LTTNG_COMPACT_EVENT_BITS,
 320                                         31);
 321                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 322                         /* Align extended struct on largest member */
 323                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 324                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 325                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 326                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 327                 }
 328                 break;
 329         case 2: /* large */
 330         {
 331                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 332                         uint32_t timestamp = (uint32_t) ctx->tsc;
 333                         uint16_t id = event_id;
 334
 335                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 336                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 337                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 338                 } else {
 339                         uint16_t id = 65535;
 340                         uint64_t timestamp = ctx->tsc;
 341
 342                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 343                         /* Align extended struct on largest member */
 344                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 345                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 346                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 347                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 348                 }
 349                 break;
 350         }
 351         default:
 352                 WARN_ON_ONCE(1);
 353         }
 354         ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 355         ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 356         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 357 }
 358
 359 static const struct lttng_ust_lib_ring_buffer_config client_config;
 360
 361 static uint64_t client_ring_buffer_clock_read(struct lttng_ust_lib_ring_buffer_channel *chan)
 362 {
 363         return lib_ring_buffer_clock_read(chan);
 364 }
 365
 366 static
 367 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 368                                  struct lttng_ust_lib_ring_buffer_channel *chan,
 369                                  size_t offset,
 370                                  size_t *pre_header_padding,
 371                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 372                                  void *client_ctx)
 373 {
 374         return record_header_size(config, chan, offset,
 375                                   pre_header_padding, ctx, client_ctx);
 376 }
 377
 378 /**
 379  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 380  *
 381  * Return header size without padding after the structure. Don't use packed
 382  * structure because gcc generates inefficient code on some architectures
 383  * (powerpc, mips..)
 384  */
 385 static size_t client_packet_header_size(void)
 386 {
 387         return offsetof(struct packet_header, ctx.header_end);
 388 }
 389
 390 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 391                                 unsigned int subbuf_idx,
 392                                 struct lttng_ust_shm_handle *handle)
 393 {
 394         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 395         struct packet_header *header =
 396                 (struct packet_header *)
 397                         lib_ring_buffer_offset_address(&buf->backend,
 398                                 subbuf_idx * chan->backend.subbuf_size,
 399                                 handle);
 400         struct lttng_channel *lttng_chan = channel_get_private(chan);
 401         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 402
 403         assert(header);
 404         if (!header)
 405                 return;
 406         header->magic = CTF_MAGIC_NUMBER;
 407         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 408         header->stream_id = lttng_chan->id;
 409         header->stream_instance_id = buf->backend.cpu;
 410         header->ctx.timestamp_begin = tsc;
 411         header->ctx.timestamp_end = 0;
 412         header->ctx.content_size = ~0ULL; /* for debugging */
 413         header->ctx.packet_size = ~0ULL;
 414         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 415         header->ctx.events_discarded = 0;
 416         header->ctx.cpu_id = buf->backend.cpu;
 417 }
 418
 419 /*
 420  * offset is assumed to never be 0 here : never deliver a completely empty
 421  * subbuffer. data_size is between 1 and subbuf_size.
 422  */
 423 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 424                               unsigned int subbuf_idx, unsigned long data_size,
 425                               struct lttng_ust_shm_handle *handle)
 426 {
 427         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 428         struct packet_header *header =
 429                 (struct packet_header *)
 430                         lib_ring_buffer_offset_address(&buf->backend,
 431                                 subbuf_idx * chan->backend.subbuf_size,
 432                                 handle);
 433         unsigned long records_lost = 0;
 434
 435         assert(header);
 436         if (!header)
 437                 return;
 438         header->ctx.timestamp_end = tsc;
 439         header->ctx.content_size =
 440                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 441         header->ctx.packet_size =
 442                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 443
 444         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 445         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 446         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 447         header->ctx.events_discarded = records_lost;
 448 }
 449
 450 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 451                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 452 {
 453         return 0;
 454 }
 455
 456 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 457 {
 458 }
 459
 460 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 461                                       size_t *offset, size_t *length)
 462 {
 463         *offset = offsetof(struct packet_header, ctx.content_size);
 464         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 465 }
 466
 467 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 468                                       size_t *offset, size_t *length)
 469 {
 470         *offset = offsetof(struct packet_header, ctx.packet_size);
 471         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 472 }
 473
 474 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 475                 struct lttng_ust_shm_handle *handle)
 476 {
 477         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 478 }
 479
 480 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 481                 struct lttng_ust_shm_handle *handle,
 482                 uint64_t *timestamp_begin)
 483 {
 484         struct packet_header *header;
 485
 486         header = client_packet_header(buf, handle);
 487         if (!header)
 488                 return -1;
 489         *timestamp_begin = header->ctx.timestamp_begin;
 490         return 0;
 491 }
 492
 493 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 494                 struct lttng_ust_shm_handle *handle,
 495                 uint64_t *timestamp_end)
 496 {
 497         struct packet_header *header;
 498
 499         header = client_packet_header(buf, handle);
 500         if (!header)
 501                 return -1;
 502         *timestamp_end = header->ctx.timestamp_end;
 503         return 0;
 504 }
 505
 506 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 507                 struct lttng_ust_shm_handle *handle,
 508                 uint64_t *events_discarded)
 509 {
 510         struct packet_header *header;
 511
 512         header = client_packet_header(buf, handle);
 513         if (!header)
 514                 return -1;
 515         *events_discarded = header->ctx.events_discarded;
 516         return 0;
 517 }
 518
 519 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 520                 struct lttng_ust_shm_handle *handle,
 521                 uint64_t *content_size)
 522 {
 523         struct packet_header *header;
 524
 525         header = client_packet_header(buf, handle);
 526         if (!header)
 527                 return -1;
 528         *content_size = header->ctx.content_size;
 529         return 0;
 530 }
 531
 532 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 533                 struct lttng_ust_shm_handle *handle,
 534                 uint64_t *packet_size)
 535 {
 536         struct packet_header *header;
 537
 538         header = client_packet_header(buf, handle);
 539         if (!header)
 540                 return -1;
 541         *packet_size = header->ctx.packet_size;
 542         return 0;
 543 }
 544
 545 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 546                 struct lttng_ust_shm_handle *handle,
 547                 uint64_t *stream_id)
 548 {
 549         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle,
 550                         buf->backend.chan);
 551         struct lttng_channel *lttng_chan = channel_get_private(chan);
 552
 553         *stream_id = lttng_chan->id;
 554
 555         return 0;
 556 }
 557
 558 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 559                 struct lttng_ust_shm_handle *handle,
 560                 uint64_t *ts)
 561 {
 562         struct lttng_ust_lib_ring_buffer_channel *chan;
 563
 564         chan = shmp(handle, handle->chan);
 565         *ts = client_ring_buffer_clock_read(chan);
 566
 567         return 0;
 568 }
 569
 570 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 571                 struct lttng_ust_shm_handle *handle,
 572                 uint64_t *seq)
 573 {
 574         struct packet_header *header;
 575
 576         header = client_packet_header(buf, handle);
 577         if (!header)
 578                 return -1;
 579         *seq = header->ctx.packet_seq_num;
 580         return 0;
 581 }
 582
 583 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 584                 struct lttng_ust_shm_handle *handle,
 585                 uint64_t *id)
 586 {
 587         *id = buf->backend.cpu;
 588
 589         return 0;
 590 }
 591
 592 static const
 593 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 594         .parent = {
 595                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 596                 .record_header_size = client_record_header_size,
 597                 .subbuffer_header_size = client_packet_header_size,
 598                 .buffer_begin = client_buffer_begin,
 599                 .buffer_end = client_buffer_end,
 600                 .buffer_create = client_buffer_create,
 601                 .buffer_finalize = client_buffer_finalize,
 602                 .content_size_field = client_content_size_field,
 603                 .packet_size_field = client_packet_size_field,
 604         },
 605         .timestamp_begin = client_timestamp_begin,
 606         .timestamp_end = client_timestamp_end,
 607         .events_discarded = client_events_discarded,
 608         .content_size = client_content_size,
 609         .packet_size = client_packet_size,
 610         .stream_id = client_stream_id,
 611         .current_timestamp = client_current_timestamp,
 612         .sequence_number = client_sequence_number,
 613         .instance_id = client_instance_id,
 614 };
 615
 616 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 617         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 618         .cb.record_header_size = client_record_header_size,
 619         .cb.subbuffer_header_size = client_packet_header_size,
 620         .cb.buffer_begin = client_buffer_begin,
 621         .cb.buffer_end = client_buffer_end,
 622         .cb.buffer_create = client_buffer_create,
 623         .cb.buffer_finalize = client_buffer_finalize,
 624         .cb.content_size_field = client_content_size_field,
 625         .cb.packet_size_field = client_packet_size_field,
 626
 627         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 628         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 629         .sync = RING_BUFFER_SYNC_GLOBAL,
 630         .mode = RING_BUFFER_MODE_TEMPLATE,
 631         .backend = RING_BUFFER_PAGE,
 632         .output = RING_BUFFER_MMAP,
 633         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 634         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 635         .wakeup = LTTNG_CLIENT_WAKEUP,
 636         .client_type = LTTNG_CLIENT_TYPE,
 637
 638         .cb_ptr = &client_cb.parent,
 639 };
 640
 641 static
 642 struct lttng_channel *_channel_create(const char *name,
 643                                 void *buf_addr,
 644                                 size_t subbuf_size, size_t num_subbuf,
 645                                 unsigned int switch_timer_interval,
 646                                 unsigned int read_timer_interval,
 647                                 unsigned char *uuid,
 648                                 uint32_t chan_id,
 649                                 const int *stream_fds, int nr_stream_fds,
 650                                 int64_t blocking_timeout)
 651 {
 652         struct lttng_channel chan_priv_init;
 653         struct lttng_ust_shm_handle *handle;
 654         struct lttng_channel *lttng_chan;
 655         void *priv;
 656
 657         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 658         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 659         chan_priv_init.id = chan_id;
 660         handle = channel_create(&client_config, name,
 661                         &priv, __alignof__(struct lttng_channel),
 662                         sizeof(struct lttng_channel),
 663                         &chan_priv_init,
 664                         buf_addr, subbuf_size, num_subbuf,
 665                         switch_timer_interval, read_timer_interval,
 666                         stream_fds, nr_stream_fds, blocking_timeout);
 667         if (!handle)
 668                 return NULL;
 669         lttng_chan = priv;
 670         lttng_chan->handle = handle;
 671         lttng_chan->chan = shmp(handle, handle->chan);
 672         return lttng_chan;
 673 }
 674
 675 static
 676 void lttng_channel_destroy(struct lttng_channel *chan)
 677 {
 678         channel_destroy(chan->chan, chan->handle, 1);
 679 }
 680
 681 static
 682 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 683                       uint32_t event_id)
 684 {
 685         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 686         struct lttng_ust_stack_ctx *lttng_ctx = ctx->priv;
 687         struct lttng_client_ctx client_ctx;
 688         int ret, cpu;
 689
 690         /* Compute internal size of context structures. */
 691         ctx_get_struct_size(lttng_ctx->chan_ctx, &client_ctx.packet_context_len,
 692                         APP_CTX_ENABLED);
 693         ctx_get_struct_size(lttng_ctx->event_ctx, &client_ctx.event_context_len,
 694                         APP_CTX_ENABLED);
 695
 696         cpu = lib_ring_buffer_get_cpu(&client_config);
 697         if (cpu < 0)
 698                 return -EPERM;
 699         ctx->cpu = cpu;
 700
 701         switch (lttng_chan->header_type) {
 702         case 1: /* compact */
 703                 if (event_id > 30)
 704                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 705                 break;
 706         case 2: /* large */
 707                 if (event_id > 65534)
 708                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 709                 break;
 710         default:
 711                 WARN_ON_ONCE(1);
 712         }
 713
 714         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 715         if (caa_unlikely(ret))
 716                 goto put;
 717         if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 718                         &ctx->backend_pages)) {
 719                 ret = -EPERM;
 720                 goto put;
 721         }
 722         lttng_write_event_header(&client_config, ctx, event_id);
 723         return 0;
 724 put:
 725         lib_ring_buffer_put_cpu(&client_config);
 726         return ret;
 727 }
 728
 729 static
 730 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 731 {
 732         lib_ring_buffer_commit(&client_config, ctx);
 733         lib_ring_buffer_put_cpu(&client_config);
 734 }
 735
 736 static
 737 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 738                      size_t len)
 739 {
 740         lib_ring_buffer_write(&client_config, ctx, src, len);
 741 }
 742
 743 static
 744 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 745                      size_t len)
 746 {
 747         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 748 }
 749
 750 #if 0
 751 static
 752 wait_queue_head_t *lttng_get_reader_wait_queue(struct lttng_ust_lib_ring_buffer_channel *chan)
 753 {
 754         return &chan->read_wait;
 755 }
 756
 757 static
 758 wait_queue_head_t *lttng_get_hp_wait_queue(struct lttng_ust_lib_ring_buffer_channel *chan)
 759 {
 760         return &chan->hp_wait;
 761 }
 762 #endif //0
 763
 764 static
 765 int lttng_is_finalized(struct lttng_ust_lib_ring_buffer_channel *chan)
 766 {
 767         return lib_ring_buffer_channel_is_finalized(chan);
 768 }
 769
 770 static
 771 int lttng_is_disabled(struct lttng_ust_lib_ring_buffer_channel *chan)
 772 {
 773         return lib_ring_buffer_channel_is_disabled(chan);
 774 }
 775
 776 static
 777 int lttng_flush_buffer(struct lttng_ust_lib_ring_buffer_channel *chan,
 778                 struct lttng_ust_shm_handle *handle)
 779 {
 780         struct lttng_ust_lib_ring_buffer *buf;
 781         int cpu;
 782
 783         for_each_channel_cpu(cpu, chan) {
 784                 int shm_fd, wait_fd, wakeup_fd;
 785                 uint64_t memory_map_size;
 786
 787                 buf = channel_get_ring_buffer(&client_config, chan,
 788                                 cpu, handle, &shm_fd, &wait_fd,
 789                                 &wakeup_fd, &memory_map_size);
 790                 lib_ring_buffer_switch(&client_config, buf,
 791                                 SWITCH_ACTIVE, handle);
 792         }
 793         return 0;
 794 }
 795
 796 static struct lttng_transport lttng_relay_transport = {
 797         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 798         .ops = {
 799                 .struct_size = sizeof(struct lttng_ust_channel_ops),
 800                 .priv = __LTTNG_COMPOUND_LITERAL(struct lttng_ust_channel_ops_private, {
 801                         .pub = &lttng_relay_transport.ops,
 802                         .channel_create = _channel_create,
 803                         .channel_destroy = lttng_channel_destroy,
 804                         .packet_avail_size = NULL,      /* Would be racy anyway */
 805                         .is_finalized = lttng_is_finalized,
 806                         .is_disabled = lttng_is_disabled,
 807                         .flush_buffer = lttng_flush_buffer,
 808                 }),
 809                 .event_reserve = lttng_event_reserve,
 810                 .event_commit = lttng_event_commit,
 811                 .event_write = lttng_event_write,
 812                 .event_strcpy = lttng_event_strcpy,
 813         },
 814         .client_config = &client_config,
 815 };
 816
 817 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 818 {
 819         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 820                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 821         lttng_transport_register(&lttng_relay_transport);
 822 }
 823
 824 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 825 {
 826         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 827                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 828         lttng_transport_unregister(&lttng_relay_transport);
 829 }