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