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 <stddef.h>
  24 #include <stdint.h>
  25 #include <lttng/ust-events.h>
  26 #include "lttng/bitfield.h"
  27 #include "clock.h"
  28 #include "lttng-tracer.h"
  29 #include "../libringbuffer/frontend_types.h"
  30
  31 #define LTTNG_COMPACT_EVENT_BITS       5
  32 #define LTTNG_COMPACT_TSC_BITS         27
  33
  34 enum app_ctx_mode {
  35         APP_CTX_DISABLED,
  36         APP_CTX_ENABLED,
  37 };
  38
  39 /*
  40  * Keep the natural field alignment for _each field_ within this structure if
  41  * you ever add/remove a field from this header. Packed attribute is not used
  42  * because gcc generates poor code on at least powerpc and mips. Don't ever
  43  * let gcc add padding between the structure elements.
  44  */
  45
  46 struct packet_header {
  47         /* Trace packet header */
  48         uint32_t magic;                 /*
  49                                          * Trace magic number.
  50                                          * contains endianness information.
  51                                          */
  52         uint8_t uuid[LTTNG_UST_UUID_LEN];
  53         uint32_t stream_id;
  54         uint64_t stream_instance_id;
  55
  56         struct {
  57                 /* Stream packet context */
  58                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  59                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  60                 uint64_t content_size;          /* Size of data in subbuffer */
  61                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  62                 uint64_t packet_seq_num;        /* Packet sequence number */
  63                 unsigned long events_discarded; /*
  64                                                  * Events lost in this subbuffer since
  65                                                  * the beginning of the trace.
  66                                                  * (may overflow)
  67                                                  */
  68                 uint32_t cpu_id;                /* CPU id associated with stream */
  69                 uint8_t header_end;             /* End of header */
  70         } ctx;
  71 };
  72
  73 struct lttng_client_ctx {
  74         size_t packet_context_len;
  75         size_t event_context_len;
  76 };
  77
  78 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  79 {
  80         return trace_clock_read64();
  81 }
  82
  83 static inline
  84 size_t ctx_get_aligned_size(size_t offset, struct lttng_ctx *ctx,
  85                 size_t ctx_len)
  86 {
  87         size_t orig_offset = offset;
  88
  89         if (caa_likely(!ctx))
  90                 return 0;
  91         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  92         offset += ctx_len;
  93         return offset - orig_offset;
  94 }
  95
  96 static inline
  97 void ctx_get_struct_size(struct lttng_ctx *ctx, size_t *ctx_len,
  98                 enum app_ctx_mode mode)
  99 {
 100         int i;
 101         size_t offset = 0;
 102
 103         if (caa_likely(!ctx)) {
 104                 *ctx_len = 0;
 105                 return;
 106         }
 107         for (i = 0; i < ctx->nr_fields; i++) {
 108                 if (mode == APP_CTX_ENABLED) {
 109                         offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 110                 } else {
 111                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 112                                 /*
 113                                  * Before UST 2.8, we cannot use the
 114                                  * application context, because we
 115                                  * cannot trust that the handler used
 116                                  * for get_size is the same used for
 117                                  * ctx_record, which would result in
 118                                  * corrupted traces when tracing
 119                                  * concurrently with application context
 120                                  * register/unregister.
 121                                  */
 122                                 offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
 123                         } else {
 124                                 offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
 125                         }
 126                 }
 127         }
 128         *ctx_len = offset;
 129 }
 130
 131 static inline
 132 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
 133                 struct lttng_channel *chan,
 134                 struct lttng_ctx *ctx,
 135                 enum app_ctx_mode mode)
 136 {
 137         int i;
 138
 139         if (caa_likely(!ctx))
 140                 return;
 141         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 142         for (i = 0; i < ctx->nr_fields; i++) {
 143                 if (mode == APP_CTX_ENABLED) {
 144                         ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 145                 } else {
 146                         if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
 147                                 /*
 148                                  * Before UST 2.8, we cannot use the
 149                                  * application context, because we
 150                                  * cannot trust that the handler used
 151                                  * for get_size is the same used for
 152                                  * ctx_record, which would result in
 153                                  * corrupted traces when tracing
 154                                  * concurrently with application context
 155                                  * register/unregister.
 156                                  */
 157                                 lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
 158                         } else {
 159                                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 160                         }
 161                 }
 162         }
 163 }
 164
 165 /*
 166  * record_header_size - Calculate the header size and padding necessary.
 167  * @config: ring buffer instance configuration
 168  * @chan: channel
 169  * @offset: offset in the write buffer
 170  * @pre_header_padding: padding to add before the header (output)
 171  * @ctx: reservation context
 172  *
 173  * Returns the event header size (including padding).
 174  *
 175  * The payload must itself determine its own alignment from the biggest type it
 176  * contains.
 177  */
 178 static __inline__
 179 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 180                                  struct channel *chan, size_t offset,
 181                                  size_t *pre_header_padding,
 182                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 183                                  struct lttng_client_ctx *client_ctx)
 184 {
 185         struct lttng_channel *lttng_chan = channel_get_private(chan);
 186         struct lttng_event *event = ctx->priv;
 187         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 188         size_t orig_offset = offset;
 189         size_t padding;
 190
 191         switch (lttng_chan->header_type) {
 192         case 1: /* compact */
 193                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 194                 offset += padding;
 195                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 196                         offset += sizeof(uint32_t);     /* id and timestamp */
 197                 } else {
 198                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 199                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 200                         /* Align extended struct on largest member */
 201                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 202                         offset += sizeof(uint32_t);     /* id */
 203                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 204                         offset += sizeof(uint64_t);     /* timestamp */
 205                 }
 206                 break;
 207         case 2: /* large */
 208                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 209                 offset += padding;
 210                 offset += sizeof(uint16_t);
 211                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 212                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 213                         offset += sizeof(uint32_t);     /* timestamp */
 214                 } else {
 215                         /* Align extended struct on largest member */
 216                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 217                         offset += sizeof(uint32_t);     /* id */
 218                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 219                         offset += sizeof(uint64_t);     /* timestamp */
 220                 }
 221                 break;
 222         default:
 223                 padding = 0;
 224                 WARN_ON_ONCE(1);
 225         }
 226         if (lttng_ctx) {
 227                 /* 2.8+ probe ABI. */
 228                 offset += ctx_get_aligned_size(offset, lttng_ctx->chan_ctx,
 229                                 client_ctx->packet_context_len);
 230                 offset += ctx_get_aligned_size(offset, lttng_ctx->event_ctx,
 231                                 client_ctx->event_context_len);
 232         } else {
 233                 /* Pre 2.8 probe ABI. */
 234                 offset += ctx_get_aligned_size(offset, lttng_chan->ctx,
 235                                 client_ctx->packet_context_len);
 236                 offset += ctx_get_aligned_size(offset, event->ctx,
 237                                 client_ctx->event_context_len);
 238         }
 239         *pre_header_padding = padding;
 240         return offset - orig_offset;
 241 }
 242
 243 #include "../libringbuffer/api.h"
 244 #include "lttng-rb-clients.h"
 245
 246 static
 247 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 248                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 249                                  uint32_t event_id);
 250
 251 /*
 252  * lttng_write_event_header
 253  *
 254  * Writes the event header to the offset (already aligned on 32-bits).
 255  *
 256  * @config: ring buffer instance configuration
 257  * @ctx: reservation context
 258  * @event_id: event ID
 259  */
 260 static __inline__
 261 void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *config,
 262                             struct lttng_ust_lib_ring_buffer_ctx *ctx,
 263                             uint32_t event_id)
 264 {
 265         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 266         struct lttng_event *event = ctx->priv;
 267         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 268
 269         if (caa_unlikely(ctx->rflags))
 270                 goto slow_path;
 271
 272         switch (lttng_chan->header_type) {
 273         case 1: /* compact */
 274         {
 275                 uint32_t id_time = 0;
 276
 277                 bt_bitfield_write(&id_time, uint32_t,
 278                                 0,
 279                                 LTTNG_COMPACT_EVENT_BITS,
 280                                 event_id);
 281                 bt_bitfield_write(&id_time, uint32_t,
 282                                 LTTNG_COMPACT_EVENT_BITS,
 283                                 LTTNG_COMPACT_TSC_BITS,
 284                                 ctx->tsc);
 285                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 286                 break;
 287         }
 288         case 2: /* large */
 289         {
 290                 uint32_t timestamp = (uint32_t) ctx->tsc;
 291                 uint16_t id = event_id;
 292
 293                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 294                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 295                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 296                 break;
 297         }
 298         default:
 299                 WARN_ON_ONCE(1);
 300         }
 301
 302         if (lttng_ctx) {
 303                 /* 2.8+ probe ABI. */
 304                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 305                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 306         } else {
 307                 /* Pre 2.8 probe ABI. */
 308                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 309                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 310         }
 311         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 312
 313         return;
 314
 315 slow_path:
 316         lttng_write_event_header_slow(config, ctx, event_id);
 317 }
 318
 319 static
 320 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
 321                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 322                                  uint32_t event_id)
 323 {
 324         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 325         struct lttng_event *event = ctx->priv;
 326         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 327
 328         switch (lttng_chan->header_type) {
 329         case 1: /* compact */
 330                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 331                         uint32_t id_time = 0;
 332
 333                         bt_bitfield_write(&id_time, uint32_t,
 334                                         0,
 335                                         LTTNG_COMPACT_EVENT_BITS,
 336                                         event_id);
 337                         bt_bitfield_write(&id_time, uint32_t,
 338                                         LTTNG_COMPACT_EVENT_BITS,
 339                                         LTTNG_COMPACT_TSC_BITS,
 340                                         ctx->tsc);
 341                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 342                 } else {
 343                         uint8_t id = 0;
 344                         uint64_t timestamp = ctx->tsc;
 345
 346                         bt_bitfield_write(&id, uint8_t,
 347                                         0,
 348                                         LTTNG_COMPACT_EVENT_BITS,
 349                                         31);
 350                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 351                         /* Align extended struct on largest member */
 352                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 353                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 354                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 355                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 356                 }
 357                 break;
 358         case 2: /* large */
 359         {
 360                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 361                         uint32_t timestamp = (uint32_t) ctx->tsc;
 362                         uint16_t id = event_id;
 363
 364                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 365                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 366                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 367                 } else {
 368                         uint16_t id = 65535;
 369                         uint64_t timestamp = ctx->tsc;
 370
 371                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 372                         /* Align extended struct on largest member */
 373                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 374                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 375                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 376                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 377                 }
 378                 break;
 379         }
 380         default:
 381                 WARN_ON_ONCE(1);
 382         }
 383         if (lttng_ctx) {
 384                 /* 2.8+ probe ABI. */
 385                 ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
 386                 ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
 387         } else {
 388                 /* Pre 2.8 probe ABI. */
 389                 ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
 390                 ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
 391         }
 392         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 393 }
 394
 395 static const struct lttng_ust_lib_ring_buffer_config client_config;
 396
 397 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 398 {
 399         return lib_ring_buffer_clock_read(chan);
 400 }
 401
 402 static
 403 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
 404                                  struct channel *chan, size_t offset,
 405                                  size_t *pre_header_padding,
 406                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 407                                  void *client_ctx)
 408 {
 409         return record_header_size(config, chan, offset,
 410                                   pre_header_padding, ctx, client_ctx);
 411 }
 412
 413 /**
 414  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 415  *
 416  * Return header size without padding after the structure. Don't use packed
 417  * structure because gcc generates inefficient code on some architectures
 418  * (powerpc, mips..)
 419  */
 420 static size_t client_packet_header_size(void)
 421 {
 422         return offsetof(struct packet_header, ctx.header_end);
 423 }
 424
 425 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 426                                 unsigned int subbuf_idx,
 427                                 struct lttng_ust_shm_handle *handle)
 428 {
 429         struct channel *chan = shmp(handle, buf->backend.chan);
 430         struct packet_header *header =
 431                 (struct packet_header *)
 432                         lib_ring_buffer_offset_address(&buf->backend,
 433                                 subbuf_idx * chan->backend.subbuf_size,
 434                                 handle);
 435         struct lttng_channel *lttng_chan = channel_get_private(chan);
 436         uint64_t cnt = shmp_index(handle, buf->backend.buf_cnt, subbuf_idx)->seq_cnt;
 437
 438         assert(header);
 439         if (!header)
 440                 return;
 441         header->magic = CTF_MAGIC_NUMBER;
 442         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 443         header->stream_id = lttng_chan->id;
 444         header->stream_instance_id = buf->backend.cpu;
 445         header->ctx.timestamp_begin = tsc;
 446         header->ctx.timestamp_end = 0;
 447         header->ctx.content_size = ~0ULL; /* for debugging */
 448         header->ctx.packet_size = ~0ULL;
 449         header->ctx.packet_seq_num = chan->backend.num_subbuf * cnt + subbuf_idx;
 450         header->ctx.events_discarded = 0;
 451         header->ctx.cpu_id = buf->backend.cpu;
 452 }
 453
 454 /*
 455  * offset is assumed to never be 0 here : never deliver a completely empty
 456  * subbuffer. data_size is between 1 and subbuf_size.
 457  */
 458 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 459                               unsigned int subbuf_idx, unsigned long data_size,
 460                               struct lttng_ust_shm_handle *handle)
 461 {
 462         struct channel *chan = shmp(handle, buf->backend.chan);
 463         struct packet_header *header =
 464                 (struct packet_header *)
 465                         lib_ring_buffer_offset_address(&buf->backend,
 466                                 subbuf_idx * chan->backend.subbuf_size,
 467                                 handle);
 468         unsigned long records_lost = 0;
 469
 470         assert(header);
 471         if (!header)
 472                 return;
 473         header->ctx.timestamp_end = tsc;
 474         header->ctx.content_size =
 475                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 476         header->ctx.packet_size =
 477                 (uint64_t) LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT;  /* in bits */
 478
 479         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 480         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 481         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 482         header->ctx.events_discarded = records_lost;
 483 }
 484
 485 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 486                                 int cpu, const char *name, struct lttng_ust_shm_handle *handle)
 487 {
 488         return 0;
 489 }
 490
 491 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *priv, int cpu, struct lttng_ust_shm_handle *handle)
 492 {
 493 }
 494
 495 static void client_content_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 496                                       size_t *offset, size_t *length)
 497 {
 498         *offset = offsetof(struct packet_header, ctx.content_size);
 499         *length = sizeof(((struct packet_header *) NULL)->ctx.content_size);
 500 }
 501
 502 static void client_packet_size_field(const struct lttng_ust_lib_ring_buffer_config *config,
 503                                       size_t *offset, size_t *length)
 504 {
 505         *offset = offsetof(struct packet_header, ctx.packet_size);
 506         *length = sizeof(((struct packet_header *) NULL)->ctx.packet_size);
 507 }
 508
 509 static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
 510                 struct lttng_ust_shm_handle *handle)
 511 {
 512         return lib_ring_buffer_read_offset_address(&buf->backend, 0, handle);
 513 }
 514
 515 static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
 516                 struct lttng_ust_shm_handle *handle,
 517                 uint64_t *timestamp_begin)
 518 {
 519         struct packet_header *header;
 520
 521         header = client_packet_header(buf, handle);
 522         if (!header)
 523                 return -1;
 524         *timestamp_begin = header->ctx.timestamp_begin;
 525         return 0;
 526 }
 527
 528 static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
 529                 struct lttng_ust_shm_handle *handle,
 530                 uint64_t *timestamp_end)
 531 {
 532         struct packet_header *header;
 533
 534         header = client_packet_header(buf, handle);
 535         if (!header)
 536                 return -1;
 537         *timestamp_end = header->ctx.timestamp_end;
 538         return 0;
 539 }
 540
 541 static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
 542                 struct lttng_ust_shm_handle *handle,
 543                 uint64_t *events_discarded)
 544 {
 545         struct packet_header *header;
 546
 547         header = client_packet_header(buf, handle);
 548         if (!header)
 549                 return -1;
 550         *events_discarded = header->ctx.events_discarded;
 551         return 0;
 552 }
 553
 554 static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
 555                 struct lttng_ust_shm_handle *handle,
 556                 uint64_t *content_size)
 557 {
 558         struct packet_header *header;
 559
 560         header = client_packet_header(buf, handle);
 561         if (!header)
 562                 return -1;
 563         *content_size = header->ctx.content_size;
 564         return 0;
 565 }
 566
 567 static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
 568                 struct lttng_ust_shm_handle *handle,
 569                 uint64_t *packet_size)
 570 {
 571         struct packet_header *header;
 572
 573         header = client_packet_header(buf, handle);
 574         if (!header)
 575                 return -1;
 576         *packet_size = header->ctx.packet_size;
 577         return 0;
 578 }
 579
 580 static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
 581                 struct lttng_ust_shm_handle *handle,
 582                 uint64_t *stream_id)
 583 {
 584         struct channel *chan = shmp(handle, buf->backend.chan);
 585         struct lttng_channel *lttng_chan = channel_get_private(chan);
 586
 587         *stream_id = lttng_chan->id;
 588
 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         if (!header)
 612                 return -1;
 613         *seq = header->ctx.packet_seq_num;
 614         return 0;
 615 }
 616
 617 static int client_instance_id(struct lttng_ust_lib_ring_buffer *buf,
 618                 struct lttng_ust_shm_handle *handle,
 619                 uint64_t *id)
 620 {
 621         *id = buf->backend.cpu;
 622
 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                                 int64_t blocking_timeout)
 687 {
 688         struct lttng_channel chan_priv_init;
 689         struct lttng_ust_shm_handle *handle;
 690         struct lttng_channel *lttng_chan;
 691         void *priv;
 692
 693         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 694         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 695         chan_priv_init.id = chan_id;
 696         handle = channel_create(&client_config, name,
 697                         &priv, __alignof__(struct lttng_channel),
 698                         sizeof(struct lttng_channel),
 699                         &chan_priv_init,
 700                         buf_addr, subbuf_size, num_subbuf,
 701                         switch_timer_interval, read_timer_interval,
 702                         stream_fds, nr_stream_fds, blocking_timeout);
 703         if (!handle)
 704                 return NULL;
 705         lttng_chan = priv;
 706         lttng_chan->handle = handle;
 707         lttng_chan->chan = shmp(handle, handle->chan);
 708         return lttng_chan;
 709 }
 710
 711 static
 712 void lttng_channel_destroy(struct lttng_channel *chan)
 713 {
 714         channel_destroy(chan->chan, chan->handle, 1);
 715 }
 716
 717 static
 718 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
 719                       uint32_t event_id)
 720 {
 721         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 722         struct lttng_event *event = ctx->priv;
 723         struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 724         struct lttng_client_ctx client_ctx;
 725         int ret, cpu;
 726
 727         /* Compute internal size of context structures. */
 728
 729         if (lttng_ctx) {
 730                 /* 2.8+ probe ABI. */
 731                 ctx_get_struct_size(lttng_ctx->chan_ctx, &client_ctx.packet_context_len,
 732                                 APP_CTX_ENABLED);
 733                 ctx_get_struct_size(lttng_ctx->event_ctx, &client_ctx.event_context_len,
 734                                 APP_CTX_ENABLED);
 735         } else {
 736                 /* Pre 2.8 probe ABI. */
 737                 ctx_get_struct_size(lttng_chan->ctx, &client_ctx.packet_context_len,
 738                                 APP_CTX_DISABLED);
 739                 ctx_get_struct_size(event->ctx, &client_ctx.event_context_len,
 740                                 APP_CTX_DISABLED);
 741         }
 742
 743         cpu = lib_ring_buffer_get_cpu(&client_config);
 744         if (cpu < 0)
 745                 return -EPERM;
 746         ctx->cpu = cpu;
 747
 748         switch (lttng_chan->header_type) {
 749         case 1: /* compact */
 750                 if (event_id > 30)
 751                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 752                 break;
 753         case 2: /* large */
 754                 if (event_id > 65534)
 755                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 756                 break;
 757         default:
 758                 WARN_ON_ONCE(1);
 759         }
 760
 761         ret = lib_ring_buffer_reserve(&client_config, ctx, &client_ctx);
 762         if (caa_unlikely(ret))
 763                 goto put;
 764         if (caa_likely(ctx->ctx_len
 765                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 766                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 767                                 &ctx->backend_pages)) {
 768                         ret = -EPERM;
 769                         goto put;
 770                 }
 771         }
 772         lttng_write_event_header(&client_config, ctx, event_id);
 773         return 0;
 774 put:
 775         lib_ring_buffer_put_cpu(&client_config);
 776         return ret;
 777 }
 778
 779 static
 780 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 781 {
 782         lib_ring_buffer_commit(&client_config, ctx);
 783         lib_ring_buffer_put_cpu(&client_config);
 784 }
 785
 786 static
 787 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 788                      size_t len)
 789 {
 790         lib_ring_buffer_write(&client_config, ctx, src, len);
 791 }
 792
 793 static
 794 void lttng_event_strcpy(struct lttng_ust_lib_ring_buffer_ctx *ctx, const char *src,
 795                      size_t len)
 796 {
 797         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 798 }
 799
 800 #if 0
 801 static
 802 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 803 {
 804         return &chan->read_wait;
 805 }
 806
 807 static
 808 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 809 {
 810         return &chan->hp_wait;
 811 }
 812 #endif //0
 813
 814 static
 815 int lttng_is_finalized(struct channel *chan)
 816 {
 817         return lib_ring_buffer_channel_is_finalized(chan);
 818 }
 819
 820 static
 821 int lttng_is_disabled(struct channel *chan)
 822 {
 823         return lib_ring_buffer_channel_is_disabled(chan);
 824 }
 825
 826 static
 827 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 828 {
 829         struct lttng_ust_lib_ring_buffer *buf;
 830         int cpu;
 831
 832         for_each_channel_cpu(cpu, chan) {
 833                 int shm_fd, wait_fd, wakeup_fd;
 834                 uint64_t memory_map_size;
 835
 836                 buf = channel_get_ring_buffer(&client_config, chan,
 837                                 cpu, handle, &shm_fd, &wait_fd,
 838                                 &wakeup_fd, &memory_map_size);
 839                 lib_ring_buffer_switch(&client_config, buf,
 840                                 SWITCH_ACTIVE, handle);
 841         }
 842         return 0;
 843 }
 844
 845 static struct lttng_transport lttng_relay_transport = {
 846         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 847         .ops = {
 848                 .channel_create = _channel_create,
 849                 .channel_destroy = lttng_channel_destroy,
 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                 .is_finalized = lttng_is_finalized,
 855                 .is_disabled = lttng_is_disabled,
 856                 .flush_buffer = lttng_flush_buffer,
 857                 .event_strcpy = lttng_event_strcpy,
 858         },
 859         .client_config = &client_config,
 860 };
 861
 862 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 863 {
 864         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 865                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 866         lttng_transport_register(&lttng_relay_transport);
 867 }
 868
 869 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 870 {
 871         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 872                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 873         lttng_transport_unregister(&lttng_relay_transport);
 874 }