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