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

   1 /*
   2  * lttng-ring-buffer-client.h
   3  *
   4  * LTTng lib ring buffer client template.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <stdint.h>
  24 #include <lttng/ust-events.h>
  25 #include "lttng/bitfield.h"
  26 #include "clock.h"
  27 #include "lttng-tracer.h"
  28 #include "../libringbuffer/frontend_types.h"
  29
  30 #define LTTNG_COMPACT_EVENT_BITS       5
  31 #define LTTNG_COMPACT_TSC_BITS         27
  32
  33 enum app_ctx_mode {
  34         APP_CTX_DISABLED,
  35         APP_CTX_ENABLED,
  36 };
  37
  38 /*
  39  * Keep the natural field alignment for _each field_ within this structure if
  40  * you ever add/remove a field from this header. Packed attribute is not used
  41  * because gcc generates poor code on at least powerpc and mips. Don't ever
  42  * let gcc add padding between the structure elements.
  43  */
  44
  45 struct packet_header {
  46         /* Trace packet header */
  47         uint32_t magic;                 /*
  48                                          * Trace magic number.
  49                                          * contains endianness information.
  50                                          */
  51         uint8_t uuid[LTTNG_UST_UUID_LEN];
  52         uint32_t stream_id;
  53         uint64_t stream_instance_id;
  54
  55         struct {
  56                 /* Stream packet context */
  57                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  58                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  59                 uint64_t content_size;          /* Size of data in subbuffer */
  60                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  61                 uint64_t packet_seq_num;        /* Packet sequence number */
  62                 unsigned long events_discarded; /*
  63                                                  * Events lost in this subbuffer since
  64                                                  * the beginning of the trace.
  65                                                  * (may overflow)
  66                                                  */
  67                 uint32_t cpu_id;                /* CPU id associated with stream */
  68                 uint8_t header_end;             /* End of header */
  69         } ctx;
  70 };
  71
  72 struct lttng_client_ctx {
  73         size_t packet_context_len;
  74         size_t event_context_len;
  75 };
  76
  77 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  78 {
  79         return trace_clock_read64();
  80 }
  81
  82 static inline
  83 size_t ctx_get_aligned_size(size_t offset, struct lttng_ctx *ctx,
  84                 size_t ctx_len)
  85 {
  86         size_t orig_offset = offset;
  87
  88         if (caa_likely(!ctx))
  89                 return 0;
  90         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  91         offset += ctx_len;
  92         return offset - orig_offset;
  93 }
  94
  95 static inline
  96 void ctx_get_struct_size(struct lttng_ctx *ctx, size_t *ctx_len,
  97                 enum app_ctx_mode mode)
  98 {
  99         int i;
 100         size_t offset = 0;
 101
 102         if (caa_likely(!ctx)) {
 103                 *ctx_len = 0;
 104                 return;
 105         }
 106         for (i = 0; i < ctx->nr_fields; i++) {
 107                 if (mode == APP_CTX_ENABLED) {
 108                         offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 109                 } else {
 110                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 111                                 /*
 112                                  * Before UST 2.8, we cannot use the
 113                                  * application context, because we
 114                                  * cannot trust that the handler used
 115                                  * for get_size is the same used for
 116                                  * ctx_record, which would result in
 117                                  * corrupted traces when tracing
 118                                  * concurrently with application context
 119                                  * register/unregister.
 120                                  */
 121                                 offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
 122                         } else {
 123                                 offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 124                         }
 125                 }
 126         }
 127         *ctx_len = offset;
 128 }
 129
 130 static inline
 131 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 132                 struct lttng_channel *chan,
 133                 struct lttng_ctx *ctx,
 134                 enum app_ctx_mode mode)
 135 {
 136         int i;
 137
 138         if (caa_likely(!ctx))
 139                 return;
 140         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 141         for (i = 0; i < ctx->nr_fields; i++) {
 142                 if (mode == APP_CTX_ENABLED) {
 143                         ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 144                 } else {
 145                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 146                                 /*
 147                                  * Before UST 2.8, we cannot use the
 148                                  * application context, because we
 149                                  * cannot trust that the handler used
 150                                  * for get_size is the same used for
 151                                  * ctx_record, which would result in
 152                                  * corrupted traces when tracing
 153                                  * concurrently with application context
 154                                  * register/unregister.
 155                                  */
 156                                 lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
 157                         } else {
 158                                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 159                         }
 160                 }
 161         }
 162 }
 163
 164 /*
 165  * record_header_size - Calculate the header size and padding necessary.
 166  * @config: ring buffer instance configuration
 167  * @chan: channel
 168  * @offset: offset in the write buffer
 169  * @pre_header_padding: padding to add before the header (output)
 170  * @ctx: reservation context
 171  *
 172  * Returns the event header size (including padding).
 173  *
 174  * The payload must itself determine its own alignment from the biggest type it
 175  * contains.
 176  */
 177 static __inline__
 178 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 179                                  struct channel *chan, size_t offset,
 180                                  size_t *pre_header_padding,
 181                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 182                                  struct lttng_client_ctx *client_ctx)
 183 {
 184         struct lttng_channel *lttng_chan = channel_get_private(chan);
 185         struct lttng_event *event = ctx->priv;
 186         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 187         size_t orig_offset = offset;
 188         size_t padding;
 189
 190         switch (lttng_chan->header_type) {
 191         case 1: /* compact */
 192                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 193                 offset += padding;
 194                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 195                         offset += sizeof(uint32_t);     /* id and timestamp */
 196                 } else {
 197                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 198                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 199                         /* Align extended struct on largest member */
 200                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 201                         offset += sizeof(uint32_t);     /* id */
 202                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 203                         offset += sizeof(uint64_t);     /* timestamp */
 204                 }
 205                 break;
 206         case 2: /* large */
 207                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 208                 offset += padding;
 209                 offset += sizeof(uint16_t);
 210                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 211                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 212                         offset += sizeof(uint32_t);     /* timestamp */
 213                 } else {
 214                         /* Align extended struct on largest member */
 215                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 216                         offset += sizeof(uint32_t);     /* id */
 217                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 218                         offset += sizeof(uint64_t);     /* timestamp */
 219                 }
 220                 break;
 221         default:
 222                 padding = 0;
 223                 WARN_ON_ONCE(1);
 224         }
 225         if (lttng_ctx) {
 226                 /* 2.8+ probe ABI. */
 227                 offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 228                                 client_ctx->packet_context_len);
 229                 offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 230                                 client_ctx->event_context_len);
 231         } else {
 232                 /* Pre 2.8 probe ABI. */
 233                 offset += ctx_get_aligned_size(offset, lttng_chan->ctx,
 234                                 client_ctx->packet_context_len);
 235                 offset += ctx_get_aligned_size(offset, event->ctx,
 236                                 client_ctx->event_context_len);
 237         }
 238         *pre_header_padding = padding;
 239         return offset - orig_offset;
 240 }
 241
 242 #include "../libringbuffer/api.h"
 243 #include "lttng-rb-clients.h"
 244
 245 static
 246 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 247                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 248                                  uint32_t event_id);
 249
 250 /*
 251  * lttng_write_event_header
 252  *
 253  * Writes the event header to the offset (already aligned on 32-bits).
 254  *
 255  * @config: ring buffer instance configuration
 256  * @ctx: reservation context
 257  * @event_id: event ID
 258  */
 259 static __inline__
 260 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 261                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 262                             uint32_t event_id)
 263 {
 264         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 265         struct lttng_event *event = ctx->priv;
 266         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 267
 268         if (caa_unlikely(ctx->rflags))
 269                 goto slow_path;
 270
 271         switch (lttng_chan->header_type) {
 272         case 1: /* compact */
 273         {
 274                 uint32_t id_time = 0;
 275
 276                 bt_bitfield_write(&id_time, uint32_t,
 277                                 0,
 278                                 LTTNG_COMPACT_EVENT_BITS,
 279                                 event_id);
 280                 bt_bitfield_write(&id_time, uint32_t,
 281                                 LTTNG_COMPACT_EVENT_BITS,
 282                                 LTTNG_COMPACT_TSC_BITS,
 283                                 ctx->tsc);
 284                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 285                 break;
 286         }
 287         case 2: /* large */
 288         {
 289                 uint32_t timestamp = (uint32_t) ctx->tsc;
 290                 uint16_t id = event_id;
 291
 292                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 293                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 294                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 295                 break;
 296         }
 297         default:
 298                 WARN_ON_ONCE(1);
 299         }
 300
 301         if (lttng_ctx) {
 302                 /* 2.8+ probe ABI. */
 303                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 304                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 305         } else {
 306                 /* Pre 2.8 probe ABI. */
 307                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 308                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 309         }
 310         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 311
 312         return;
 313
 314 slow_path:
 315         lttng_write_event_header_slow(config, ctx, event_id);
 316 }
 317
 318 static
 319 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 320                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 321                                  uint32_t event_id)
 322 {
 323         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 324         struct lttng_event *event = ctx->priv;
 325         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 326
 327         switch (lttng_chan->header_type) {
 328         case 1: /* compact */
 329                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 330                         uint32_t id_time = 0;
 331
 332                         bt_bitfield_write(&id_time, uint32_t,
 333                                         0,
 334                                         LTTNG_COMPACT_EVENT_BITS,
 335                                         event_id);
 336                         bt_bitfield_write(&id_time, uint32_t,
 337                                         LTTNG_COMPACT_EVENT_BITS,
 338                                         LTTNG_COMPACT_TSC_BITS,
 339                                         ctx->tsc);
 340                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 341                 } else {
 342                         uint8_t id = 0;
 343                         uint64_t timestamp = ctx->tsc;
 344
 345                         bt_bitfield_write(&id, uint8_t,
 346                                         0,
 347                                         LTTNG_COMPACT_EVENT_BITS,
 348                                         31);
 349                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 350                         /* Align extended struct on largest member */
 351                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 352                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 353                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 354                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 355                 }
 356                 break;
 357         case 2: /* large */
 358         {
 359                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 360                         uint32_t timestamp = (uint32_t) ctx->tsc;
 361                         uint16_t id = event_id;
 362
 363                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 364                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 365                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 366                 } else {
 367                         uint16_t id = 65535;
 368                         uint64_t timestamp = ctx->tsc;
 369
 370                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 371                         /* Align extended struct on largest member */
 372                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 373                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 374                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 375                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 376                 }
 377                 break;
 378         }
 379         default:
 380                 WARN_ON_ONCE(1);
 381         }
 382         if (lttng_ctx) {
 383                 /* 2.8+ probe ABI. */
 384                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 385                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 386         } else {
 387                 /* Pre 2.8 probe ABI. */
 388                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 389                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 390         }
 391         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 392 }
 393
 394 static const struct lttng_ust_lib_ring_buffer_config client_config;
 395
 396 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 397 {
 398         return lib_ring_buffer_clock_read(chan);
 399 }
 400
 401 static
 402 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 403                                  struct channel *chan, size_t offset,
 404                                  size_t *pre_header_padding,
 405                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 406                                  void *client_ctx)
 407 {
 408         return record_header_size(config, chan, offset,
 409                                   pre_header_padding, ctx, client_ctx);
 410 }
 411
 412 /**
 413  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 414  *
 415  * Return header size without padding after the structure. Don't use packed
 416  * structure because gcc generates inefficient code on some architectures
 417  * (powerpc, mips..)
 418  */
 419 static size_t client_packet_header_size(void)
 420 {
 421         return offsetof(struct packet_header, ctx.header_end);
 422 }
 423
 424 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 425                                 unsigned int subbuf_idx,
 426                                 struct lttng_ust_shm_handle *handle)
 427 {
 428         struct channel *chan = shmp(handle, buf->backend.chan);
 429         struct packet_header *header =
 430                 (struct packet_header *)
 431                         lib_ring_buffer_offset_address(&buf->backend,
 432                                 subbuf_idx * chan->backend.subbuf_size,
 433                                 handle);
 434         struct lttng_channel *lttng_chan = channel_get_private(chan);
 435         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 436
 437         assert(header);
 438         if (!header)
 439                 return;
 440         header->magic = CTF_MAGIC_NUMBER;
 441         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 442         header->stream_id = lttng_chan->id;
 443         header->stream_instance_id = buf->backend.cpu;
 444         header->ctx.timestamp_begin = tsc;
 445         header->ctx.timestamp_end = 0;
 446         header->ctx.content_size = ~0ULL; /* for debugging */
 447         header->ctx.packet_size = ~0ULL;
 448         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 449         header->ctx.events_discarded = 0;
 450         header->ctx.cpu_id = buf->backend.cpu;
 451 }
 452
 453 /*
 454  * offset is assumed to never be 0 here : never deliver a completely empty
 455  * subbuffer. data_size is between 1 and subbuf_size.
 456  */
 457 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 458                               unsigned int subbuf_idx, unsigned long data_size,
 459                               struct lttng_ust_shm_handle *handle)
 460 {
 461         struct channel *chan = shmp(handle, buf->backend.chan);
 462         struct packet_header *header =
 463                 (struct packet_header *)
 464                         lib_ring_buffer_offset_address(&buf->backend,
 465                                 subbuf_idx * chan->backend.subbuf_size,
 466                                 handle);
 467         unsigned long records_lost = 0;
 468
 469         assert(header);
 470         if (!header)
 471                 return;
 472         header->ctx.timestamp_end = tsc;
 473         header->ctx.content_size =
 474                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 475         header->ctx.packet_size =
 476                 (uint64_t) PAGE_ALIGN(data_size) * CHAR_BIT;    /* in bits */
 477
 478         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 479         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 480         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 481         header->ctx.events_discarded = records_lost;
 482 }
 483
 484 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 485                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 486 {
 487         return 0;
 488 }
 489
 490 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 491 {
 492 }
 493
 494 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 495                                       size_t *offset, size_t *length)
 496 {
 497         *offset = offsetof(struct packet_header, ctx.content_size);
 498         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 499 }
 500
 501 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 502                                       size_t *offset, size_t *length)
 503 {
 504         *offset = offsetof(struct packet_header, ctx.packet_size);
 505         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 506 }
 507
 508 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 509                 struct lttng_ust_shm_handle *handle)
 510 {
 511         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 512 }
 513
 514 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 515                 struct lttng_ust_shm_handle *handle,
 516                 uint64_t *timestamp_begin)
 517 {
 518         struct packet_header *header;
 519
 520         header = client_packet_header(buf, handle);
 521         if (!header)
 522                 return -1;
 523         *timestamp_begin = header->ctx.timestamp_begin;
 524         return 0;
 525 }
 526
 527 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 528                 struct lttng_ust_shm_handle *handle,
 529                 uint64_t *timestamp_end)
 530 {
 531         struct packet_header *header;
 532
 533         header = client_packet_header(buf, handle);
 534         if (!header)
 535                 return -1;
 536         *timestamp_end = header->ctx.timestamp_end;
 537         return 0;
 538 }
 539
 540 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 541                 struct lttng_ust_shm_handle *handle,
 542                 uint64_t *events_discarded)
 543 {
 544         struct packet_header *header;
 545
 546         header = client_packet_header(buf, handle);
 547         if (!header)
 548                 return -1;
 549         *events_discarded = header->ctx.events_discarded;
 550         return 0;
 551 }
 552
 553 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 554                 struct lttng_ust_shm_handle *handle,
 555                 uint64_t *content_size)
 556 {
 557         struct packet_header *header;
 558
 559         header = client_packet_header(buf, handle);
 560         if (!header)
 561                 return -1;
 562         *content_size = header->ctx.content_size;
 563         return 0;
 564 }
 565
 566 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 567                 struct lttng_ust_shm_handle *handle,
 568                 uint64_t *packet_size)
 569 {
 570         struct packet_header *header;
 571
 572         header = client_packet_header(buf, handle);
 573         if (!header)
 574                 return -1;
 575         *packet_size = header->ctx.packet_size;
 576         return 0;
 577 }
 578
 579 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 580                 struct lttng_ust_shm_handle *handle,
 581                 uint64_t *stream_id)
 582 {
 583         struct packet_header *header;
 584
 585         header = client_packet_header(buf, handle);
 586         if (!header)
 587                 return -1;
 588         *stream_id = header->stream_id;
 589         return 0;
 590 }
 591
 592 static int client_current_timestamp(struct lttng_ust_lib_ring_buffer *buf,
 593                 struct lttng_ust_shm_handle *handle,
 594                 uint64_t *ts)
 595 {
 596         struct channel *chan;
 597
 598         chan = shmp(handle, handle->chan);
 599         *ts = client_ring_buffer_clock_read(chan);
 600
 601         return 0;
 602 }
 603
 604 static int client_sequence_number(struct lttng_ust_lib_ring_buffer *buf,
 605                 struct lttng_ust_shm_handle *handle,
 606                 uint64_t *seq)
 607 {
 608         struct packet_header *header;
 609
 610         header = client_packet_header(buf, handle);
 611         *seq = header->ctx.packet_seq_num;
 612         return 0;
 613 }
 614
 615 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 616                 struct lttng_ust_shm_handle *handle,
 617                 uint64_t *id)
 618 {
 619         struct packet_header *header;
 620
 621         header = client_packet_header(buf, handle);
 622         *id = header->stream_instance_id;
 623         return 0;
 624 }
 625
 626 static const
 627 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 628         .parent = {
 629                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 630                 .record_header_size = client_record_header_size,
 631                 .subbuffer_header_size = client_packet_header_size,
 632                 .buffer_begin = client_buffer_begin,
 633                 .buffer_end = client_buffer_end,
 634                 .buffer_create = client_buffer_create,
 635                 .buffer_finalize = client_buffer_finalize,
 636                 .content_size_field = client_content_size_field,
 637                 .packet_size_field = client_packet_size_field,
 638         },
 639         .timestamp_begin = client_timestamp_begin,
 640         .timestamp_end = client_timestamp_end,
 641         .events_discarded = client_events_discarded,
 642         .content_size = client_content_size,
 643         .packet_size = client_packet_size,
 644         .stream_id = client_stream_id,
 645         .current_timestamp = client_current_timestamp,
 646         .sequence_number = client_sequence_number,
 647         .instance_id = client_instance_id,
 648 };
 649
 650 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 651         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 652         .cb.record_header_size = client_record_header_size,
 653         .cb.subbuffer_header_size = client_packet_header_size,
 654         .cb.buffer_begin = client_buffer_begin,
 655         .cb.buffer_end = client_buffer_end,
 656         .cb.buffer_create = client_buffer_create,
 657         .cb.buffer_finalize = client_buffer_finalize,
 658         .cb.content_size_field = client_content_size_field,
 659         .cb.packet_size_field = client_packet_size_field,
 660
 661         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 662         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 663         .sync = RING_BUFFER_SYNC_GLOBAL,
 664         .mode = RING_BUFFER_MODE_TEMPLATE,
 665         .backend = RING_BUFFER_PAGE,
 666         .output = RING_BUFFER_MMAP,
 667         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 668         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 669         .wakeup = LTTNG_CLIENT_WAKEUP,
 670         .client_type = LTTNG_CLIENT_TYPE,
 671
 672         .cb_ptr = &client_cb.parent,
 673 };
 674
 675 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 676
 677 static
 678 struct lttng_channel *_channel_create(const char *name,
 679                                 void *buf_addr,
 680                                 size_t subbuf_size, size_t num_subbuf,
 681                                 unsigned int switch_timer_interval,
 682                                 unsigned int read_timer_interval,
 683                                 unsigned char *uuid,
 684                                 uint32_t chan_id,
 685                                 const int *stream_fds, int nr_stream_fds)
 686 {
 687         struct lttng_channel chan_priv_init;
 688         struct lttng_ust_shm_handle *handle;
 689         struct lttng_channel *lttng_chan;
 690         void *priv;
 691
 692         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 693         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 694         chan_priv_init.id = chan_id;
 695         handle = channel_create(&client_config, name,
 696                         &priv, __alignof__(struct lttng_channel),
 697                         sizeof(struct lttng_channel),
 698                         &chan_priv_init,
 699                         buf_addr, subbuf_size, num_subbuf,
 700                         switch_timer_interval, read_timer_interval,
 701                         stream_fds, nr_stream_fds);
 702         if (!handle)
 703                 return NULL;
 704         lttng_chan = priv;
 705         lttng_chan->handle = handle;
 706         lttng_chan->chan = shmp(handle, handle->chan);
 707         return lttng_chan;
 708 }
 709
 710 static
 711 void lttng_channel_destroy(struct lttng_channel *chan)
 712 {
 713         channel_destroy(chan->chan, chan->handle, 1);
 714 }
 715
 716 static
 717 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 718                       uint32_t event_id)
 719 {
 720         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 721         struct lttng_event *event = ctx->priv;
 722         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 723         struct lttng_client_ctx client_ctx;
 724         int ret, cpu;
 725
 726         /* Compute internal size of context structures. */
 727
 728         if (lttng_ctx) {
 729                 /* 2.8+ probe ABI. */
 730                 ctx_get_struct_size(lttng_ctx->chan_ctx, &client_ctx.packet_context_len,
 731                                 APP_CTX_ENABLED);
 732                 ctx_get_struct_size(lttng_ctx->event_ctx, &client_ctx.event_context_len,
 733                                 APP_CTX_ENABLED);
 734         } else {
 735                 /* Pre 2.8 probe ABI. */
 736                 ctx_get_struct_size(lttng_chan->ctx, &client_ctx.packet_context_len,
 737                                 APP_CTX_DISABLED);
 738                 ctx_get_struct_size(event->ctx, &client_ctx.event_context_len,
 739                                 APP_CTX_DISABLED);
 740         }
 741
 742         cpu = lib_ring_buffer_get_cpu(&client_config);
 743         if (cpu < 0)
 744                 return -EPERM;
 745         ctx->cpu = cpu;
 746
 747         switch (lttng_chan->header_type) {
 748         case 1: /* compact */
 749                 if (event_id > 30)
 750                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 751                 break;
 752         case 2: /* large */
 753                 if (event_id > 65534)
 754                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 755                 break;
 756         default:
 757                 WARN_ON_ONCE(1);
 758         }
 759
 760         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 761         if (caa_unlikely(ret))
 762                 goto put;
 763         if (caa_likely(ctx->ctx_len
 764                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 765                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 766                                 &ctx->backend_pages)) {
 767                         ret = -EPERM;
 768                         goto put;
 769                 }
 770         }
 771         lttng_write_event_header(&client_config, ctx, event_id);
 772         return 0;
 773 put:
 774         lib_ring_buffer_put_cpu(&client_config);
 775         return ret;
 776 }
 777
 778 static
 779 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 780 {
 781         lib_ring_buffer_commit(&client_config, ctx);
 782         lib_ring_buffer_put_cpu(&client_config);
 783 }
 784
 785 static
 786 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 787                      size_t len)
 788 {
 789         lib_ring_buffer_write(&client_config, ctx, src, len);
 790 }
 791
 792 static
 793 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 794                      size_t len)
 795 {
 796         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 797 }
 798
 799 #if 0
 800 static
 801 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 802 {
 803         return &chan->read_wait;
 804 }
 805
 806 static
 807 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 808 {
 809         return &chan->hp_wait;
 810 }
 811 #endif //0
 812
 813 static
 814 int lttng_is_finalized(struct channel *chan)
 815 {
 816         return lib_ring_buffer_channel_is_finalized(chan);
 817 }
 818
 819 static
 820 int lttng_is_disabled(struct channel *chan)
 821 {
 822         return lib_ring_buffer_channel_is_disabled(chan);
 823 }
 824
 825 static
 826 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 827 {
 828         struct lttng_ust_lib_ring_buffer *buf;
 829         int cpu;
 830
 831         for_each_channel_cpu(cpu, chan) {
 832                 int shm_fd, wait_fd, wakeup_fd;
 833                 uint64_t memory_map_size;
 834
 835                 buf = channel_get_ring_buffer(&client_config, chan,
 836                                 cpu, handle, &shm_fd, &wait_fd,
 837                                 &wakeup_fd, &memory_map_size);
 838                 lib_ring_buffer_switch(&client_config, buf,
 839                                 SWITCH_ACTIVE, handle);
 840         }
 841         return 0;
 842 }
 843
 844 static struct lttng_transport lttng_relay_transport = {
 845         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 846         .ops = {
 847                 .channel_create = _channel_create,
 848                 .channel_destroy = lttng_channel_destroy,
 849                 .u.has_strcpy = 1,
 850                 .event_reserve = lttng_event_reserve,
 851                 .event_commit = lttng_event_commit,
 852                 .event_write = lttng_event_write,
 853                 .packet_avail_size = NULL,      /* Would be racy anyway */
 854                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 855                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 856                 .is_finalized = lttng_is_finalized,
 857                 .is_disabled = lttng_is_disabled,
 858                 .flush_buffer = lttng_flush_buffer,
 859                 .event_strcpy = lttng_event_strcpy,
 860         },
 861         .client_config = &client_config,
 862 };
 863
 864 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 865 {
 866         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 867                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 868         lttng_transport_register(&lttng_relay_transport);
 869 }
 870
 871 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 872 {
 873         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 874                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 875         lttng_transport_unregister(&lttng_relay_transport);
 876 }