lttng-ring-buffer-metadata-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 <linux/module.h>
  24 #include <linux/types.h>
  25 #include <wrapper/vmalloc.h>    /* for wrapper_vmalloc_sync_all() */
  26 #include <lttng-events.h>
  27 #include <lttng-tracer.h>
  28
  29 static struct lttng_transport lttng_relay_transport;
  30
  31 struct metadata_packet_header {
  32         uint32_t magic;                 /* 0x75D11D57 */
  33         uint8_t  uuid[16];              /* Unique Universal Identifier */
  34         uint32_t checksum;              /* 0 if unused */
  35         uint32_t content_size;          /* in bits */
  36         uint32_t packet_size;           /* in bits */
  37         uint8_t  compression_scheme;    /* 0 if unused */
  38         uint8_t  encryption_scheme;     /* 0 if unused */
  39         uint8_t  checksum_scheme;       /* 0 if unused */
  40         uint8_t  major;                 /* CTF spec major version number */
  41         uint8_t  minor;                 /* CTF spec minor version number */
  42         uint8_t  header_end[0];
  43 };
  44
  45 struct metadata_record_header {
  46         uint8_t header_end[0];          /* End of header */
  47 };
  48
  49 static const struct lib_ring_buffer_config client_config;
  50
  51 static inline
  52 u64 lib_ring_buffer_clock_read(struct channel *chan)
  53 {
  54         return 0;
  55 }
  56
  57 static inline
  58 size_t record_header_size(const struct lib_ring_buffer_config *config,
  59                                  struct channel *chan, size_t offset,
  60                                  size_t *pre_header_padding,
  61                                  struct lib_ring_buffer_ctx *ctx,
  62                                  void *client_ctx)
  63 {
  64         return 0;
  65 }
  66
  67 #include <wrapper/ringbuffer/api.h>
  68
  69 static u64 client_ring_buffer_clock_read(struct channel *chan)
  70 {
  71         return 0;
  72 }
  73
  74 static
  75 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  76                                  struct channel *chan, size_t offset,
  77                                  size_t *pre_header_padding,
  78                                  struct lib_ring_buffer_ctx *ctx,
  79                                  void *client_ctx)
  80 {
  81         return 0;
  82 }
  83
  84 /**
  85  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  86  *
  87  * Return header size without padding after the structure. Don't use packed
  88  * structure because gcc generates inefficient code on some architectures
  89  * (powerpc, mips..)
  90  */
  91 static size_t client_packet_header_size(void)
  92 {
  93         return offsetof(struct metadata_packet_header, header_end);
  94 }
  95
  96 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  97                                 unsigned int subbuf_idx)
  98 {
  99         struct channel *chan = buf->backend.chan;
 100         struct metadata_packet_header *header =
 101                 (struct metadata_packet_header *)
 102                         lib_ring_buffer_offset_address(&buf->backend,
 103                                 subbuf_idx * chan->backend.subbuf_size);
 104         struct lttng_metadata_cache *metadata_cache =
 105                 channel_get_private(chan);
 106
 107         header->magic = TSDL_MAGIC_NUMBER;
 108         memcpy(header->uuid, metadata_cache->uuid.b,
 109                 sizeof(metadata_cache->uuid));
 110         header->checksum = 0;           /* 0 if unused */
 111         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 112         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 113         header->compression_scheme = 0; /* 0 if unused */
 114         header->encryption_scheme = 0;  /* 0 if unused */
 115         header->checksum_scheme = 0;    /* 0 if unused */
 116         header->major = CTF_SPEC_MAJOR;
 117         header->minor = CTF_SPEC_MINOR;
 118 }
 119
 120 /*
 121  * offset is assumed to never be 0 here : never deliver a completely empty
 122  * subbuffer. data_size is between 1 and subbuf_size.
 123  */
 124 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 125                               unsigned int subbuf_idx, unsigned long data_size)
 126 {
 127         struct channel *chan = buf->backend.chan;
 128         struct metadata_packet_header *header =
 129                 (struct metadata_packet_header *)
 130                         lib_ring_buffer_offset_address(&buf->backend,
 131                                 subbuf_idx * chan->backend.subbuf_size);
 132         unsigned long records_lost = 0;
 133
 134         header->content_size = data_size * CHAR_BIT;            /* in bits */
 135         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 136         /*
 137          * We do not care about the records lost count, because the metadata
 138          * channel waits and retry.
 139          */
 140         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 141         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 142         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 143         WARN_ON_ONCE(records_lost != 0);
 144 }
 145
 146 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 147                                 int cpu, const char *name)
 148 {
 149         return 0;
 150 }
 151
 152 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 153 {
 154 }
 155
 156 static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
 157                 struct lib_ring_buffer *buf, uint64_t *timestamp_begin)
 158 {
 159         return -ENOSYS;
 160 }
 161
 162 static int client_timestamp_end(const struct lib_ring_buffer_config *config,
 163                         struct lib_ring_buffer *bufb,
 164                         uint64_t *timestamp_end)
 165 {
 166         return -ENOSYS;
 167 }
 168
 169 static int client_events_discarded(const struct lib_ring_buffer_config *config,
 170                         struct lib_ring_buffer *bufb,
 171                         uint64_t *events_discarded)
 172 {
 173         return -ENOSYS;
 174 }
 175
 176 static int client_current_timestamp(const struct lib_ring_buffer_config *config,
 177                 struct lib_ring_buffer *bufb,
 178                 uint64_t *ts)
 179 {
 180         return -ENOSYS;
 181 }
 182
 183 static int client_content_size(const struct lib_ring_buffer_config *config,
 184                         struct lib_ring_buffer *bufb,
 185                         uint64_t *content_size)
 186 {
 187         return -ENOSYS;
 188 }
 189
 190 static int client_packet_size(const struct lib_ring_buffer_config *config,
 191                         struct lib_ring_buffer *bufb,
 192                         uint64_t *packet_size)
 193 {
 194         return -ENOSYS;
 195 }
 196
 197 static int client_stream_id(const struct lib_ring_buffer_config *config,
 198                         struct lib_ring_buffer *bufb,
 199                         uint64_t *stream_id)
 200 {
 201         return -ENOSYS;
 202 }
 203
 204 static int client_sequence_number(const struct lib_ring_buffer_config *config,
 205                         struct lib_ring_buffer *bufb,
 206                         uint64_t *seq)
 207 {
 208         return -ENOSYS;
 209 }
 210
 211 static
 212 int client_instance_id(const struct lib_ring_buffer_config *config,
 213                 struct lib_ring_buffer *bufb,
 214                 uint64_t *id)
 215 {
 216         return -ENOSYS;
 217 }
 218
 219 static const struct lib_ring_buffer_config client_config = {
 220         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 221         .cb.record_header_size = client_record_header_size,
 222         .cb.subbuffer_header_size = client_packet_header_size,
 223         .cb.buffer_begin = client_buffer_begin,
 224         .cb.buffer_end = client_buffer_end,
 225         .cb.buffer_create = client_buffer_create,
 226         .cb.buffer_finalize = client_buffer_finalize,
 227
 228         .tsc_bits = 0,
 229         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 230         .sync = RING_BUFFER_SYNC_GLOBAL,
 231         .mode = RING_BUFFER_MODE_TEMPLATE,
 232         .backend = RING_BUFFER_PAGE,
 233         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 234         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 235         .ipi = RING_BUFFER_IPI_BARRIER,
 236         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 237 };
 238
 239 static
 240 void release_priv_ops(void *priv_ops)
 241 {
 242         module_put(THIS_MODULE);
 243 }
 244
 245 static
 246 void lttng_channel_destroy(struct channel *chan)
 247 {
 248         channel_destroy(chan);
 249 }
 250
 251 static
 252 struct channel *_channel_create(const char *name,
 253                                 struct lttng_channel *lttng_chan, void *buf_addr,
 254                                 size_t subbuf_size, size_t num_subbuf,
 255                                 unsigned int switch_timer_interval,
 256                                 unsigned int read_timer_interval)
 257 {
 258         struct channel *chan;
 259
 260         chan = channel_create(&client_config, name,
 261                               lttng_chan->session->metadata_cache, buf_addr,
 262                               subbuf_size, num_subbuf, switch_timer_interval,
 263                               read_timer_interval);
 264         if (chan) {
 265                 /*
 266                  * Ensure this module is not unloaded before we finish
 267                  * using lttng_relay_transport.ops.
 268                  */
 269                 if (!try_module_get(THIS_MODULE)) {
 270                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 271                         goto error;
 272                 }
 273                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 274                 chan->backend.release_priv_ops = release_priv_ops;
 275         }
 276         return chan;
 277
 278 error:
 279         lttng_channel_destroy(chan);
 280         return NULL;
 281 }
 282
 283 static
 284 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 285 {
 286         struct lib_ring_buffer *buf;
 287
 288         buf = channel_get_ring_buffer(&client_config, chan, 0);
 289         if (!lib_ring_buffer_open_read(buf))
 290                 return buf;
 291         return NULL;
 292 }
 293
 294 static
 295 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 296 {
 297         struct lib_ring_buffer *buf;
 298         int cpu;
 299
 300         for_each_channel_cpu(cpu, chan) {
 301                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 302                 if (!atomic_long_read(&buf->active_readers))
 303                         return 1;
 304         }
 305         return 0;
 306 }
 307
 308 static
 309 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 310 {
 311         lib_ring_buffer_release_read(buf);
 312 }
 313
 314 static
 315 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 316 {
 317         int ret;
 318
 319         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 320         if (ret)
 321                 return ret;
 322         lib_ring_buffer_backend_get_pages(&client_config, ctx,
 323                         &ctx->backend_pages);
 324         return 0;
 325
 326 }
 327
 328 static
 329 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 330 {
 331         lib_ring_buffer_commit(&client_config, ctx);
 332 }
 333
 334 static
 335 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 336                      size_t len)
 337 {
 338         lib_ring_buffer_write(&client_config, ctx, src, len);
 339 }
 340
 341 static
 342 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 343                                const void __user *src, size_t len)
 344 {
 345         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 346 }
 347
 348 static
 349 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 350                 int c, size_t len)
 351 {
 352         lib_ring_buffer_memset(&client_config, ctx, c, len);
 353 }
 354
 355 static
 356 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 357                 size_t len)
 358 {
 359         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 360 }
 361
 362 static
 363 size_t lttng_packet_avail_size(struct channel *chan)
 364
 365 {
 366         unsigned long o_begin;
 367         struct lib_ring_buffer *buf;
 368
 369         buf = chan->backend.buf;        /* Only for global buffer ! */
 370         o_begin = v_read(&client_config, &buf->offset);
 371         if (subbuf_offset(o_begin, chan) != 0) {
 372                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 373         } else {
 374                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 375                         - sizeof(struct metadata_packet_header);
 376         }
 377 }
 378
 379 static
 380 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 381 {
 382         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 383                                         chan, cpu);
 384         return &buf->write_wait;
 385 }
 386
 387 static
 388 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 389 {
 390         return &chan->hp_wait;
 391 }
 392
 393 static
 394 int lttng_is_finalized(struct channel *chan)
 395 {
 396         return lib_ring_buffer_channel_is_finalized(chan);
 397 }
 398
 399 static
 400 int lttng_is_disabled(struct channel *chan)
 401 {
 402         return lib_ring_buffer_channel_is_disabled(chan);
 403 }
 404
 405 static struct lttng_transport lttng_relay_transport = {
 406         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 407         .owner = THIS_MODULE,
 408         .ops = {
 409                 .channel_create = _channel_create,
 410                 .channel_destroy = lttng_channel_destroy,
 411                 .buffer_read_open = lttng_buffer_read_open,
 412                 .buffer_has_read_closed_stream =
 413                         lttng_buffer_has_read_closed_stream,
 414                 .buffer_read_close = lttng_buffer_read_close,
 415                 .event_reserve = lttng_event_reserve,
 416                 .event_commit = lttng_event_commit,
 417                 .event_write_from_user = lttng_event_write_from_user,
 418                 .event_memset = lttng_event_memset,
 419                 .event_write = lttng_event_write,
 420                 .event_strcpy = lttng_event_strcpy,
 421                 .packet_avail_size = lttng_packet_avail_size,
 422                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 423                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 424                 .is_finalized = lttng_is_finalized,
 425                 .is_disabled = lttng_is_disabled,
 426                 .timestamp_begin = client_timestamp_begin,
 427                 .timestamp_end = client_timestamp_end,
 428                 .events_discarded = client_events_discarded,
 429                 .content_size = client_content_size,
 430                 .packet_size = client_packet_size,
 431                 .stream_id = client_stream_id,
 432                 .current_timestamp = client_current_timestamp,
 433                 .sequence_number = client_sequence_number,
 434                 .instance_id = client_instance_id,
 435         },
 436 };
 437
 438 static int __init lttng_ring_buffer_client_init(void)
 439 {
 440         /*
 441          * This vmalloc sync all also takes care of the lib ring buffer
 442          * vmalloc'd module pages when it is built as a module into LTTng.
 443          */
 444         wrapper_vmalloc_sync_all();
 445         lttng_transport_register(&lttng_relay_transport);
 446         return 0;
 447 }
 448
 449 module_init(lttng_ring_buffer_client_init);
 450
 451 static void __exit lttng_ring_buffer_client_exit(void)
 452 {
 453         lttng_transport_unregister(&lttng_relay_transport);
 454 }
 455
 456 module_exit(lttng_ring_buffer_client_exit);
 457
 458 MODULE_LICENSE("GPL and additional rights");
 459 MODULE_AUTHOR("Mathieu Desnoyers");
 460 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 461                    " client");