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