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