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 unsigned char 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 const struct lib_ring_buffer_config client_config = {
 203         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 204         .cb.record_header_size = client_record_header_size,
 205         .cb.subbuffer_header_size = client_packet_header_size,
 206         .cb.buffer_begin = client_buffer_begin,
 207         .cb.buffer_end = client_buffer_end,
 208         .cb.buffer_create = client_buffer_create,
 209         .cb.buffer_finalize = client_buffer_finalize,
 210
 211         .tsc_bits = 0,
 212         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 213         .sync = RING_BUFFER_SYNC_GLOBAL,
 214         .mode = RING_BUFFER_MODE_TEMPLATE,
 215         .backend = RING_BUFFER_PAGE,
 216         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 217         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 218         .ipi = RING_BUFFER_IPI_BARRIER,
 219         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 220 };
 221
 222 static
 223 void release_priv_ops(void *priv_ops)
 224 {
 225         module_put(THIS_MODULE);
 226 }
 227
 228 static
 229 void lttng_channel_destroy(struct channel *chan)
 230 {
 231         channel_destroy(chan);
 232 }
 233
 234 static
 235 struct channel *_channel_create(const char *name,
 236                                 struct lttng_channel *lttng_chan, void *buf_addr,
 237                                 size_t subbuf_size, size_t num_subbuf,
 238                                 unsigned int switch_timer_interval,
 239                                 unsigned int read_timer_interval)
 240 {
 241         struct channel *chan;
 242
 243         chan = channel_create(&client_config, name,
 244                               lttng_chan->session->metadata_cache, buf_addr,
 245                               subbuf_size, num_subbuf, switch_timer_interval,
 246                               read_timer_interval);
 247         if (chan) {
 248                 /*
 249                  * Ensure this module is not unloaded before we finish
 250                  * using lttng_relay_transport.ops.
 251                  */
 252                 if (!try_module_get(THIS_MODULE)) {
 253                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 254                         goto error;
 255                 }
 256                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 257                 chan->backend.release_priv_ops = release_priv_ops;
 258         }
 259         return chan;
 260
 261 error:
 262         lttng_channel_destroy(chan);
 263         return NULL;
 264 }
 265
 266 static
 267 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 268 {
 269         struct lib_ring_buffer *buf;
 270
 271         buf = channel_get_ring_buffer(&client_config, chan, 0);
 272         if (!lib_ring_buffer_open_read(buf))
 273                 return buf;
 274         return NULL;
 275 }
 276
 277 static
 278 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 279 {
 280         struct lib_ring_buffer *buf;
 281         int cpu;
 282
 283         for_each_channel_cpu(cpu, chan) {
 284                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 285                 if (!atomic_long_read(&buf->active_readers))
 286                         return 1;
 287         }
 288         return 0;
 289 }
 290
 291 static
 292 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 293 {
 294         lib_ring_buffer_release_read(buf);
 295 }
 296
 297 static
 298 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 299 {
 300         return lib_ring_buffer_reserve(&client_config, ctx);
 301 }
 302
 303 static
 304 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 305 {
 306         lib_ring_buffer_commit(&client_config, ctx);
 307 }
 308
 309 static
 310 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 311                      size_t len)
 312 {
 313         lib_ring_buffer_write(&client_config, ctx, src, len);
 314 }
 315
 316 static
 317 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 318                                const void __user *src, size_t len)
 319 {
 320         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 321 }
 322
 323 static
 324 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 325                 int c, size_t len)
 326 {
 327         lib_ring_buffer_memset(&client_config, ctx, c, len);
 328 }
 329
 330 static
 331 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 332                 size_t len)
 333 {
 334         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 335 }
 336
 337 static
 338 size_t lttng_packet_avail_size(struct channel *chan)
 339
 340 {
 341         unsigned long o_begin;
 342         struct lib_ring_buffer *buf;
 343
 344         buf = chan->backend.buf;        /* Only for global buffer ! */
 345         o_begin = v_read(&client_config, &buf->offset);
 346         if (subbuf_offset(o_begin, chan) != 0) {
 347                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 348         } else {
 349                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 350                         - sizeof(struct metadata_packet_header);
 351         }
 352 }
 353
 354 static
 355 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 356 {
 357         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 358                                         chan, cpu);
 359         return &buf->write_wait;
 360 }
 361
 362 static
 363 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 364 {
 365         return &chan->hp_wait;
 366 }
 367
 368 static
 369 int lttng_is_finalized(struct channel *chan)
 370 {
 371         return lib_ring_buffer_channel_is_finalized(chan);
 372 }
 373
 374 static
 375 int lttng_is_disabled(struct channel *chan)
 376 {
 377         return lib_ring_buffer_channel_is_disabled(chan);
 378 }
 379
 380 static struct lttng_transport lttng_relay_transport = {
 381         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 382         .owner = THIS_MODULE,
 383         .ops = {
 384                 .channel_create = _channel_create,
 385                 .channel_destroy = lttng_channel_destroy,
 386                 .buffer_read_open = lttng_buffer_read_open,
 387                 .buffer_has_read_closed_stream =
 388                         lttng_buffer_has_read_closed_stream,
 389                 .buffer_read_close = lttng_buffer_read_close,
 390                 .event_reserve = lttng_event_reserve,
 391                 .event_commit = lttng_event_commit,
 392                 .event_write_from_user = lttng_event_write_from_user,
 393                 .event_memset = lttng_event_memset,
 394                 .event_write = lttng_event_write,
 395                 .event_strcpy = lttng_event_strcpy,
 396                 .packet_avail_size = lttng_packet_avail_size,
 397                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 398                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 399                 .is_finalized = lttng_is_finalized,
 400                 .is_disabled = lttng_is_disabled,
 401                 .timestamp_begin = client_timestamp_begin,
 402                 .timestamp_end = client_timestamp_end,
 403                 .events_discarded = client_events_discarded,
 404                 .content_size = client_content_size,
 405                 .packet_size = client_packet_size,
 406                 .stream_id = client_stream_id,
 407                 .current_timestamp = client_current_timestamp,
 408         },
 409 };
 410
 411 static int __init lttng_ring_buffer_client_init(void)
 412 {
 413         /*
 414          * This vmalloc sync all also takes care of the lib ring buffer
 415          * vmalloc'd module pages when it is built as a module into LTTng.
 416          */
 417         wrapper_vmalloc_sync_all();
 418         lttng_transport_register(&lttng_relay_transport);
 419         return 0;
 420 }
 421
 422 module_init(lttng_ring_buffer_client_init);
 423
 424 static void __exit lttng_ring_buffer_client_exit(void)
 425 {
 426         lttng_transport_unregister(&lttng_relay_transport);
 427 }
 428
 429 module_exit(lttng_ring_buffer_client_exit);
 430
 431 MODULE_LICENSE("GPL and additional rights");
 432 MODULE_AUTHOR("Mathieu Desnoyers");
 433 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 434                    " client");