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