src/common/ringbuffer-clients/template.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  */
   8
   9 #include <limits.h>
  10 #include <stddef.h>
  11 #include <stdint.h>
  12
  13 #include <lttng/urcu/pointer.h>
  14 #include <urcu/tls-compat.h>
  15
  16 #include "common/events.h"
  17 #include "common/bitfield.h"
  18 #include "common/align.h"
  19 #include "common/clock.h"
  20 #include "common/ringbuffer/frontend_types.h"
  21
  22 #define LTTNG_COMPACT_EVENT_BITS       5
  23 #define LTTNG_COMPACT_TSC_BITS         27
  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         struct lttng_ust_ctx *chan_ctx;
  63         struct lttng_ust_ctx *event_ctx;
  64 };
  65
  66 /*
  67  * Indexed by lib_ring_buffer_nesting_count().
  68  */
  69 typedef struct lttng_ust_ring_buffer_ctx_private private_ctx_stack_t[LIB_RING_BUFFER_MAX_NESTING];
  70 static DEFINE_URCU_TLS(private_ctx_stack_t, private_ctx_stack);
  71
  72 /*
  73  * Force a read (imply TLS allocation for dlopen) of TLS variables.
  74  */
  75 void RING_BUFFER_MODE_TEMPLATE_ALLOC_TLS(void)
  76 {
  77         asm volatile ("" : : "m" (URCU_TLS(private_ctx_stack)));
  78 }
  79
  80 static inline uint64_t lib_ring_buffer_clock_read(
  81                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)))
  82 {
  83         return trace_clock_read64();
  84 }
  85
  86 static inline
  87 size_t ctx_get_aligned_size(size_t offset, struct lttng_ust_ctx *ctx,
  88                 size_t ctx_len)
  89 {
  90         size_t orig_offset = offset;
  91
  92         if (caa_likely(!ctx))
  93                 return 0;
  94         offset += lttng_ust_ring_buffer_align(offset, ctx->largest_align);
  95         offset += ctx_len;
  96         return offset - orig_offset;
  97 }
  98
  99 static inline
 100 void ctx_get_struct_size(struct lttng_ust_ring_buffer_ctx *bufctx,
 101                 struct lttng_ust_ctx *ctx, size_t *ctx_len)
 102 {
 103         int i;
 104         size_t offset = 0;
 105
 106         if (caa_likely(!ctx)) {
 107                 *ctx_len = 0;
 108                 return;
 109         }
 110         for (i = 0; i < ctx->nr_fields; i++)
 111                 offset += ctx->fields[i].get_size(ctx->fields[i].priv, bufctx->probe_ctx, offset);
 112         *ctx_len = offset;
 113 }
 114
 115 static inline
 116 void ctx_record(struct lttng_ust_ring_buffer_ctx *bufctx,
 117                 struct lttng_ust_channel_buffer *chan,
 118                 struct lttng_ust_ctx *ctx)
 119 {
 120         int i;
 121
 122         if (caa_likely(!ctx))
 123                 return;
 124         lttng_ust_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 125         for (i = 0; i < ctx->nr_fields; i++)
 126                 ctx->fields[i].record(ctx->fields[i].priv, bufctx->probe_ctx, bufctx, chan);
 127 }
 128
 129 /*
 130  * record_header_size - Calculate the header size and padding necessary.
 131  * @config: ring buffer instance configuration
 132  * @chan: channel
 133  * @offset: offset in the write buffer
 134  * @pre_header_padding: padding to add before the header (output)
 135  * @ctx: reservation context
 136  *
 137  * Returns the event header size (including padding).
 138  *
 139  * The payload must itself determine its own alignment from the biggest type it
 140  * contains.
 141  */
 142 static __inline__
 143 size_t record_header_size(
 144                 const struct lttng_ust_ring_buffer_config *config __attribute__((unused)),
 145                 struct lttng_ust_ring_buffer_channel *chan,
 146                 size_t offset,
 147                 size_t *pre_header_padding,
 148                 struct lttng_ust_ring_buffer_ctx *ctx,
 149                 struct lttng_client_ctx *client_ctx)
 150 {
 151         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 152         size_t orig_offset = offset;
 153         size_t padding;
 154
 155         switch (lttng_chan->priv->header_type) {
 156         case 1: /* compact */
 157                 padding = lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint32_t));
 158                 offset += padding;
 159                 if (!(ctx->priv->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 160                         offset += sizeof(uint32_t);     /* id and timestamp */
 161                 } else {
 162                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 163                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 164                         /* Align extended struct on largest member */
 165                         offset += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 166                         offset += sizeof(uint32_t);     /* id */
 167                         offset += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 168                         offset += sizeof(uint64_t);     /* timestamp */
 169                 }
 170                 break;
 171         case 2: /* large */
 172                 padding = lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint16_t));
 173                 offset += padding;
 174                 offset += sizeof(uint16_t);
 175                 if (!(ctx->priv->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 176                         offset += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint32_t));
 177                         offset += sizeof(uint32_t);     /* timestamp */
 178                 } else {
 179                         /* Align extended struct on largest member */
 180                         offset += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 181                         offset += sizeof(uint32_t);     /* id */
 182                         offset += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(uint64_t));
 183                         offset += sizeof(uint64_t);     /* timestamp */
 184                 }
 185                 break;
 186         default:
 187                 padding = 0;
 188                 WARN_ON_ONCE(1);
 189         }
 190         offset += ctx_get_aligned_size(offset, client_ctx->chan_ctx,
 191                         client_ctx->packet_context_len);
 192         offset += ctx_get_aligned_size(offset, client_ctx->event_ctx,
 193                         client_ctx->event_context_len);
 194         *pre_header_padding = padding;
 195         return offset - orig_offset;
 196 }
 197
 198 #include "common/ringbuffer/api.h"
 199 #include "common/ringbuffer-clients/clients.h"
 200
 201 static
 202 void lttng_write_event_header_slow(const struct lttng_ust_ring_buffer_config *config,
 203                                  struct lttng_ust_ring_buffer_ctx *ctx,
 204                                  struct lttng_client_ctx *client_ctx,
 205                                  uint32_t event_id);
 206
 207 /*
 208  * lttng_write_event_header
 209  *
 210  * Writes the event header to the offset (already aligned on 32-bits).
 211  *
 212  * @config: ring buffer instance configuration
 213  * @ctx: reservation context
 214  * @event_id: event ID
 215  */
 216 static __inline__
 217 void lttng_write_event_header(const struct lttng_ust_ring_buffer_config *config,
 218                             struct lttng_ust_ring_buffer_ctx *ctx,
 219                             struct lttng_client_ctx *client_ctx,
 220                             uint32_t event_id)
 221 {
 222         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(ctx->priv->chan);
 223
 224         if (caa_unlikely(ctx->priv->rflags))
 225                 goto slow_path;
 226
 227         switch (lttng_chan->priv->header_type) {
 228         case 1: /* compact */
 229         {
 230                 uint32_t id_time = 0;
 231
 232                 bt_bitfield_write(&id_time, uint32_t,
 233                                 0,
 234                                 LTTNG_COMPACT_EVENT_BITS,
 235                                 event_id);
 236                 bt_bitfield_write(&id_time, uint32_t,
 237                                 LTTNG_COMPACT_EVENT_BITS,
 238                                 LTTNG_COMPACT_TSC_BITS,
 239                                 ctx->priv->tsc);
 240                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 241                 break;
 242         }
 243         case 2: /* large */
 244         {
 245                 uint32_t timestamp = (uint32_t) ctx->priv->tsc;
 246                 uint16_t id = event_id;
 247
 248                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 249                 lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint32_t));
 250                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 251                 break;
 252         }
 253         default:
 254                 WARN_ON_ONCE(1);
 255         }
 256
 257         ctx_record(ctx, lttng_chan, client_ctx->chan_ctx);
 258         ctx_record(ctx, lttng_chan, client_ctx->event_ctx);
 259         lttng_ust_ring_buffer_align_ctx(ctx, ctx->largest_align);
 260
 261         return;
 262
 263 slow_path:
 264         lttng_write_event_header_slow(config, ctx, client_ctx, event_id);
 265 }
 266
 267 static
 268 void lttng_write_event_header_slow(const struct lttng_ust_ring_buffer_config *config,
 269                                  struct lttng_ust_ring_buffer_ctx *ctx,
 270                                  struct lttng_client_ctx *client_ctx,
 271                                  uint32_t event_id)
 272 {
 273         struct lttng_ust_ring_buffer_ctx_private *ctx_private = ctx->priv;
 274         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(ctx->priv->chan);
 275
 276         switch (lttng_chan->priv->header_type) {
 277         case 1: /* compact */
 278                 if (!(ctx_private->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 279                         uint32_t id_time = 0;
 280
 281                         bt_bitfield_write(&id_time, uint32_t,
 282                                         0,
 283                                         LTTNG_COMPACT_EVENT_BITS,
 284                                         event_id);
 285                         bt_bitfield_write(&id_time, uint32_t,
 286                                         LTTNG_COMPACT_EVENT_BITS,
 287                                         LTTNG_COMPACT_TSC_BITS,
 288                                         ctx_private->tsc);
 289                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 290                 } else {
 291                         uint8_t id = 0;
 292                         uint64_t timestamp = ctx_private->tsc;
 293
 294                         bt_bitfield_write(&id, uint8_t,
 295                                         0,
 296                                         LTTNG_COMPACT_EVENT_BITS,
 297                                         31);
 298                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 299                         /* Align extended struct on largest member */
 300                         lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 301                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 302                         lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 303                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 304                 }
 305                 break;
 306         case 2: /* large */
 307         {
 308                 if (!(ctx_private->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 309                         uint32_t timestamp = (uint32_t) ctx_private->tsc;
 310                         uint16_t id = event_id;
 311
 312                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 313                         lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint32_t));
 314                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 315                 } else {
 316                         uint16_t id = 65535;
 317                         uint64_t timestamp = ctx_private->tsc;
 318
 319                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 320                         /* Align extended struct on largest member */
 321                         lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 322                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 323                         lttng_ust_ring_buffer_align_ctx(ctx, lttng_ust_rb_alignof(uint64_t));
 324                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 325                 }
 326                 break;
 327         }
 328         default:
 329                 WARN_ON_ONCE(1);
 330         }
 331         ctx_record(ctx, lttng_chan, client_ctx->chan_ctx);
 332         ctx_record(ctx, lttng_chan, client_ctx->event_ctx);
 333         lttng_ust_ring_buffer_align_ctx(ctx, ctx->largest_align);
 334 }
 335
 336 static const struct lttng_ust_ring_buffer_config client_config;
 337
 338 static uint64_t client_ring_buffer_clock_read(struct lttng_ust_ring_buffer_channel *chan)
 339 {
 340         return lib_ring_buffer_clock_read(chan);
 341 }
 342
 343 static
 344 size_t client_record_header_size(const struct lttng_ust_ring_buffer_config *config,
 345                                  struct lttng_ust_ring_buffer_channel *chan,
 346                                  size_t offset,
 347                                  size_t *pre_header_padding,
 348                                  struct lttng_ust_ring_buffer_ctx *ctx,
 349                                  void *client_ctx)
 350 {
 351         return record_header_size(config, chan, offset,
 352                                   pre_header_padding, ctx, client_ctx);
 353 }
 354
 355 /**
 356  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 357  *
 358  * Return header size without padding after the structure. Don't use packed
 359  * structure because gcc generates inefficient code on some architectures
 360  * (powerpc, mips..)
 361  */
 362 static size_t client_packet_header_size(void)
 363 {
 364         return offsetof(struct packet_header, ctx.header_end);
 365 }
 366
 367 static void client_buffer_begin(struct lttng_ust_ring_buffer *buf, uint64_t tsc,
 368                                 unsigned int subbuf_idx,
 369                                 struct lttng_ust_shm_handle *handle)
 370 {
 371         struct lttng_ust_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 372         struct packet_header *header =
 373                 (struct packet_header *)
 374                         lib_ring_buffer_offset_address(&buf->backend,
 375                                 subbuf_idx * chan->backend.subbuf_size,
 376                                 handle);
 377         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 378         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 379
 380         assert(header);
 381         if (!header)
 382                 return;
 383         header->magic = CTF_MAGIC_NUMBER;
 384         memcpy(header->uuid, lttng_chan->priv->uuid, sizeof(lttng_chan->priv->uuid));
 385         header->stream_id = lttng_chan->priv->id;
 386         header->stream_instance_id = buf->backend.cpu;
 387         header->ctx.timestamp_begin = tsc;
 388         header->ctx.timestamp_end = 0;
 389         header->ctx.content_size = ~0ULL; /* for debugging */
 390         header->ctx.packet_size = ~0ULL;
 391         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 392         header->ctx.events_discarded = 0;
 393         header->ctx.cpu_id = buf->backend.cpu;
 394 }
 395
 396 /*
 397  * offset is assumed to never be 0 here : never deliver a completely empty
 398  * subbuffer. data_size is between 1 and subbuf_size.
 399  */
 400 static void client_buffer_end(struct lttng_ust_ring_buffer *buf, uint64_t tsc,
 401                               unsigned int subbuf_idx, unsigned long data_size,
 402                               struct lttng_ust_shm_handle *handle)
 403 {
 404         struct lttng_ust_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 405         struct packet_header *header =
 406                 (struct packet_header *)
 407                         lib_ring_buffer_offset_address(&buf->backend,
 408                                 subbuf_idx * chan->backend.subbuf_size,
 409                                 handle);
 410         unsigned long records_lost = 0;
 411
 412         assert(header);
 413         if (!header)
 414                 return;
 415         header->ctx.timestamp_end = tsc;
 416         header->ctx.content_size =
 417                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 418         header->ctx.packet_size =
 419                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 420
 421         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 422         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 423         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 424         header->ctx.events_discarded = records_lost;
 425 }
 426
 427 static int client_buffer_create(
 428                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 429                 void *priv __attribute__((unused)),
 430                 int cpu __attribute__((unused)),
 431                 const char *name __attribute__((unused)),
 432                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 433 {
 434         return 0;
 435 }
 436
 437 static void client_buffer_finalize(
 438                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 439                 void *priv __attribute__((unused)),
 440                 int cpu __attribute__((unused)),
 441                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 442 {
 443 }
 444
 445 static void client_content_size_field(
 446                 const struct lttng_ust_ring_buffer_config *config __attribute__((unused)),
 447                 size_t *offset, size_t *length)
 448 {
 449         *offset = offsetof(struct packet_header, ctx.content_size);
 450         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 451 }
 452
 453 static void client_packet_size_field(
 454                 const struct lttng_ust_ring_buffer_config *config __attribute__((unused)),
 455                 size_t *offset, size_t *length)
 456 {
 457         *offset = offsetof(struct packet_header, ctx.packet_size);
 458         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 459 }
 460
 461 static struct packet_header *client_packet_header(struct lttng_ust_ring_buffer *buf,
 462                 struct lttng_ust_shm_handle *handle)
 463 {
 464         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 465 }
 466
 467 static int client_timestamp_begin(struct lttng_ust_ring_buffer *buf,
 468                 struct lttng_ust_ring_buffer_channel *chan,
 469                 uint64_t *timestamp_begin)
 470 {
 471         struct lttng_ust_shm_handle *handle = chan->handle;
 472         struct packet_header *header;
 473
 474         header = client_packet_header(buf, handle);
 475         if (!header)
 476                 return -1;
 477         *timestamp_begin = header->ctx.timestamp_begin;
 478         return 0;
 479 }
 480
 481 static int client_timestamp_end(struct lttng_ust_ring_buffer *buf,
 482                 struct lttng_ust_ring_buffer_channel *chan,
 483                 uint64_t *timestamp_end)
 484 {
 485         struct lttng_ust_shm_handle *handle = chan->handle;
 486         struct packet_header *header;
 487
 488         header = client_packet_header(buf, handle);
 489         if (!header)
 490                 return -1;
 491         *timestamp_end = header->ctx.timestamp_end;
 492         return 0;
 493 }
 494
 495 static int client_events_discarded(struct lttng_ust_ring_buffer *buf,
 496                 struct lttng_ust_ring_buffer_channel *chan,
 497                 uint64_t *events_discarded)
 498 {
 499         struct lttng_ust_shm_handle *handle = chan->handle;
 500         struct packet_header *header;
 501
 502         header = client_packet_header(buf, handle);
 503         if (!header)
 504                 return -1;
 505         *events_discarded = header->ctx.events_discarded;
 506         return 0;
 507 }
 508
 509 static int client_content_size(struct lttng_ust_ring_buffer *buf,
 510                 struct lttng_ust_ring_buffer_channel *chan,
 511                 uint64_t *content_size)
 512 {
 513         struct lttng_ust_shm_handle *handle = chan->handle;
 514         struct packet_header *header;
 515
 516         header = client_packet_header(buf, handle);
 517         if (!header)
 518                 return -1;
 519         *content_size = header->ctx.content_size;
 520         return 0;
 521 }
 522
 523 static int client_packet_size(struct lttng_ust_ring_buffer *buf,
 524                 struct lttng_ust_ring_buffer_channel *chan,
 525                 uint64_t *packet_size)
 526 {
 527         struct lttng_ust_shm_handle *handle = chan->handle;
 528         struct packet_header *header;
 529
 530         header = client_packet_header(buf, handle);
 531         if (!header)
 532                 return -1;
 533         *packet_size = header->ctx.packet_size;
 534         return 0;
 535 }
 536
 537 static int client_stream_id(struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 538                 struct lttng_ust_ring_buffer_channel *chan,
 539                 uint64_t *stream_id)
 540 {
 541         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 542
 543         *stream_id = lttng_chan->priv->id;
 544
 545         return 0;
 546 }
 547
 548 static int client_current_timestamp(
 549                 struct lttng_ust_ring_buffer *buf  __attribute__((unused)),
 550                 struct lttng_ust_ring_buffer_channel *chan,
 551                 uint64_t *ts)
 552 {
 553         *ts = client_ring_buffer_clock_read(chan);
 554
 555         return 0;
 556 }
 557
 558 static int client_sequence_number(struct lttng_ust_ring_buffer *buf,
 559                 struct lttng_ust_ring_buffer_channel *chan,
 560                 uint64_t *seq)
 561 {
 562         struct lttng_ust_shm_handle *handle = chan->handle;
 563         struct packet_header *header;
 564
 565         header = client_packet_header(buf, handle);
 566         if (!header)
 567                 return -1;
 568         *seq = header->ctx.packet_seq_num;
 569         return 0;
 570 }
 571
 572 static int client_instance_id(struct lttng_ust_ring_buffer *buf,
 573                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)),
 574                 uint64_t *id)
 575 {
 576         *id = buf->backend.cpu;
 577
 578         return 0;
 579 }
 580
 581 static const
 582 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 583         .parent = {
 584                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 585                 .record_header_size = client_record_header_size,
 586                 .subbuffer_header_size = client_packet_header_size,
 587                 .buffer_begin = client_buffer_begin,
 588                 .buffer_end = client_buffer_end,
 589                 .buffer_create = client_buffer_create,
 590                 .buffer_finalize = client_buffer_finalize,
 591                 .content_size_field = client_content_size_field,
 592                 .packet_size_field = client_packet_size_field,
 593         },
 594         .timestamp_begin = client_timestamp_begin,
 595         .timestamp_end = client_timestamp_end,
 596         .events_discarded = client_events_discarded,
 597         .content_size = client_content_size,
 598         .packet_size = client_packet_size,
 599         .stream_id = client_stream_id,
 600         .current_timestamp = client_current_timestamp,
 601         .sequence_number = client_sequence_number,
 602         .instance_id = client_instance_id,
 603 };
 604
 605 static const struct lttng_ust_ring_buffer_config client_config = {
 606         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 607         .cb.record_header_size = client_record_header_size,
 608         .cb.subbuffer_header_size = client_packet_header_size,
 609         .cb.buffer_begin = client_buffer_begin,
 610         .cb.buffer_end = client_buffer_end,
 611         .cb.buffer_create = client_buffer_create,
 612         .cb.buffer_finalize = client_buffer_finalize,
 613         .cb.content_size_field = client_content_size_field,
 614         .cb.packet_size_field = client_packet_size_field,
 615
 616         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 617         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 618         .sync = RING_BUFFER_SYNC_GLOBAL,
 619         .mode = RING_BUFFER_MODE_TEMPLATE,
 620         .backend = RING_BUFFER_PAGE,
 621         .output = RING_BUFFER_MMAP,
 622         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 623         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 624         .wakeup = LTTNG_CLIENT_WAKEUP,
 625         .client_type = LTTNG_CLIENT_TYPE,
 626
 627         .cb_ptr = &client_cb.parent,
 628 };
 629
 630 static
 631 struct lttng_ust_channel_buffer *_channel_create(const char *name,
 632                                 void *buf_addr,
 633                                 size_t subbuf_size, size_t num_subbuf,
 634                                 unsigned int switch_timer_interval,
 635                                 unsigned int read_timer_interval,
 636                                 unsigned char *uuid,
 637                                 uint32_t chan_id,
 638                                 const int *stream_fds, int nr_stream_fds,
 639                                 int64_t blocking_timeout)
 640 {
 641         struct lttng_ust_abi_channel_config chan_priv_init;
 642         struct lttng_ust_shm_handle *handle;
 643         struct lttng_ust_channel_buffer *lttng_chan_buf;
 644
 645         lttng_chan_buf = lttng_ust_alloc_channel_buffer();
 646         if (!lttng_chan_buf)
 647                 return NULL;
 648         memcpy(lttng_chan_buf->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
 649         lttng_chan_buf->priv->id = chan_id;
 650
 651         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 652         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 653         chan_priv_init.id = chan_id;
 654
 655         handle = channel_create(&client_config, name,
 656                         __alignof__(struct lttng_ust_abi_channel_config),
 657                         sizeof(struct lttng_ust_abi_channel_config),
 658                         &chan_priv_init,
 659                         lttng_chan_buf, buf_addr, subbuf_size, num_subbuf,
 660                         switch_timer_interval, read_timer_interval,
 661                         stream_fds, nr_stream_fds, blocking_timeout);
 662         if (!handle)
 663                 goto error;
 664         lttng_chan_buf->priv->rb_chan = shmp(handle, handle->chan);
 665         return lttng_chan_buf;
 666
 667 error:
 668         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 669         return NULL;
 670 }
 671
 672 static
 673 void lttng_channel_destroy(struct lttng_ust_channel_buffer *lttng_chan_buf)
 674 {
 675         channel_destroy(lttng_chan_buf->priv->rb_chan, lttng_chan_buf->priv->rb_chan->handle, 1);
 676         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 677 }
 678
 679 static
 680 int lttng_event_reserve(struct lttng_ust_ring_buffer_ctx *ctx)
 681 {
 682         struct lttng_ust_event_recorder *event_recorder = ctx->client_priv;
 683         struct lttng_ust_channel_buffer *lttng_chan = event_recorder->chan;
 684         struct lttng_client_ctx client_ctx;
 685         int ret, nesting;
 686         struct lttng_ust_ring_buffer_ctx_private *private_ctx;
 687         uint32_t event_id;
 688
 689         event_id = event_recorder->priv->id;
 690         client_ctx.chan_ctx = lttng_ust_rcu_dereference(lttng_chan->priv->ctx);
 691         client_ctx.event_ctx = lttng_ust_rcu_dereference(event_recorder->priv->ctx);
 692         /* Compute internal size of context structures. */
 693         ctx_get_struct_size(ctx, client_ctx.chan_ctx, &client_ctx.packet_context_len);
 694         ctx_get_struct_size(ctx, client_ctx.event_ctx, &client_ctx.event_context_len);
 695
 696         nesting = lib_ring_buffer_nesting_inc(&client_config);
 697         if (nesting < 0)
 698                 return -EPERM;
 699
 700         private_ctx = &URCU_TLS(private_ctx_stack)[nesting];
 701         memset(private_ctx, 0, sizeof(*private_ctx));
 702         private_ctx->pub = ctx;
 703         private_ctx->chan = lttng_chan->priv->rb_chan;
 704
 705         ctx->priv = private_ctx;
 706
 707         switch (lttng_chan->priv->header_type) {
 708         case 1: /* compact */
 709                 if (event_id > 30)
 710                         private_ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 711                 break;
 712         case 2: /* large */
 713                 if (event_id > 65534)
 714                         private_ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 715                 break;
 716         default:
 717                 WARN_ON_ONCE(1);
 718         }
 719
 720         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 721         if (caa_unlikely(ret))
 722                 goto put;
 723         if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 724                         &private_ctx->backend_pages)) {
 725                 ret = -EPERM;
 726                 goto put;
 727         }
 728         lttng_write_event_header(&client_config, ctx, &client_ctx, event_id);
 729         return 0;
 730 put:
 731         lib_ring_buffer_nesting_dec(&client_config);
 732         return ret;
 733 }
 734
 735 static
 736 void lttng_event_commit(struct lttng_ust_ring_buffer_ctx *ctx)
 737 {
 738         lib_ring_buffer_commit(&client_config, ctx);
 739         lib_ring_buffer_nesting_dec(&client_config);
 740 }
 741
 742 static
 743 void lttng_event_write(struct lttng_ust_ring_buffer_ctx *ctx,
 744                 const void *src, size_t len, size_t alignment)
 745 {
 746         lttng_ust_ring_buffer_align_ctx(ctx, alignment);
 747         lib_ring_buffer_write(&client_config, ctx, src, len);
 748 }
 749
 750 static
 751 void lttng_event_strcpy(struct lttng_ust_ring_buffer_ctx *ctx,
 752                 const char *src, size_t len)
 753 {
 754         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 755 }
 756
 757 static
 758 void lttng_event_pstrcpy_pad(struct lttng_ust_ring_buffer_ctx *ctx,
 759                 const char *src, size_t len)
 760 {
 761         lib_ring_buffer_pstrcpy(&client_config, ctx, src, len, '\0');
 762 }
 763
 764 static
 765 int lttng_is_finalized(struct lttng_ust_channel_buffer *chan)
 766 {
 767         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 768
 769         return lib_ring_buffer_channel_is_finalized(rb_chan);
 770 }
 771
 772 static
 773 int lttng_is_disabled(struct lttng_ust_channel_buffer *chan)
 774 {
 775         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 776
 777         return lib_ring_buffer_channel_is_disabled(rb_chan);
 778 }
 779
 780 static
 781 int lttng_flush_buffer(struct lttng_ust_channel_buffer *chan)
 782 {
 783         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 784         struct lttng_ust_ring_buffer *buf;
 785         int cpu;
 786
 787         for_each_channel_cpu(cpu, rb_chan) {
 788                 int shm_fd, wait_fd, wakeup_fd;
 789                 uint64_t memory_map_size;
 790
 791                 buf = channel_get_ring_buffer(&client_config, rb_chan,
 792                                 cpu, rb_chan->handle, &shm_fd, &wait_fd,
 793                                 &wakeup_fd, &memory_map_size);
 794                 lib_ring_buffer_switch(&client_config, buf,
 795                                 SWITCH_ACTIVE, rb_chan->handle);
 796         }
 797         return 0;
 798 }
 799
 800 static struct lttng_transport lttng_relay_transport = {
 801         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 802         .ops = {
 803                 .struct_size = sizeof(struct lttng_ust_channel_buffer_ops),
 804                 .priv = LTTNG_UST_COMPOUND_LITERAL(struct lttng_ust_channel_buffer_ops_private, {
 805                         .pub = &lttng_relay_transport.ops,
 806                         .channel_create = _channel_create,
 807                         .channel_destroy = lttng_channel_destroy,
 808                         .packet_avail_size = NULL,      /* Would be racy anyway */
 809                         .is_finalized = lttng_is_finalized,
 810                         .is_disabled = lttng_is_disabled,
 811                         .flush_buffer = lttng_flush_buffer,
 812                 }),
 813                 .event_reserve = lttng_event_reserve,
 814                 .event_commit = lttng_event_commit,
 815                 .event_write = lttng_event_write,
 816                 .event_strcpy = lttng_event_strcpy,
 817                 .event_pstrcpy_pad = lttng_event_pstrcpy_pad,
 818         },
 819         .client_config = &client_config,
 820 };
 821
 822 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 823 {
 824         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 825                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 826         lttng_transport_register(&lttng_relay_transport);
 827 }
 828
 829 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 830 {
 831         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 832                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 833         lttng_transport_unregister(&lttng_relay_transport);
 834 }