src/lttng-ring-buffer-metadata-client.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-ring-buffer-client.h
   4  *
   5  * LTTng lib ring buffer client template.
   6  *
   7  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <wrapper/vmalloc.h>    /* for wrapper_vmalloc_sync_mappings() */
  13 #include <lttng/events.h>
  14 #include <lttng/events-internal.h>
  15 #include <lttng/tracer.h>
  16
  17 static struct lttng_transport lttng_relay_transport;
  18
  19 struct metadata_packet_header {
  20         uint32_t magic;                 /* 0x75D11D57 */
  21         uint8_t  uuid[16];              /* Unique Universal Identifier */
  22         uint32_t checksum;              /* 0 if unused */
  23         uint32_t content_size;          /* in bits */
  24         uint32_t packet_size;           /* in bits */
  25         uint8_t  compression_scheme;    /* 0 if unused */
  26         uint8_t  encryption_scheme;     /* 0 if unused */
  27         uint8_t  checksum_scheme;       /* 0 if unused */
  28         uint8_t  major;                 /* CTF spec major version number */
  29         uint8_t  minor;                 /* CTF spec minor version number */
  30         uint8_t  header_end[0];
  31 };
  32
  33 struct metadata_record_header {
  34         uint8_t header_end[0];          /* End of header */
  35 };
  36
  37 static const struct lttng_kernel_ring_buffer_config client_config;
  38
  39 static inline
  40 u64 lib_ring_buffer_clock_read(struct lttng_kernel_ring_buffer_channel *chan)
  41 {
  42         return 0;
  43 }
  44
  45 static inline
  46 size_t record_header_size(const struct lttng_kernel_ring_buffer_config *config,
  47                                  struct lttng_kernel_ring_buffer_channel *chan, size_t offset,
  48                                  size_t *pre_header_padding,
  49                                  struct lttng_kernel_ring_buffer_ctx *ctx,
  50                                  void *client_ctx)
  51 {
  52         return 0;
  53 }
  54
  55 #include <ringbuffer/api.h>
  56
  57 static u64 client_ring_buffer_clock_read(struct lttng_kernel_ring_buffer_channel *chan)
  58 {
  59         return 0;
  60 }
  61
  62 static
  63 size_t client_record_header_size(const struct lttng_kernel_ring_buffer_config *config,
  64                                  struct lttng_kernel_ring_buffer_channel *chan, size_t offset,
  65                                  size_t *pre_header_padding,
  66                                  struct lttng_kernel_ring_buffer_ctx *ctx,
  67                                  void *client_ctx)
  68 {
  69         return 0;
  70 }
  71
  72 /**
  73  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  74  *
  75  * Return header size without padding after the structure. Don't use packed
  76  * structure because gcc generates inefficient code on some architectures
  77  * (powerpc, mips..)
  78  */
  79 static size_t client_packet_header_size(void)
  80 {
  81         return offsetof(struct metadata_packet_header, header_end);
  82 }
  83
  84 static void client_buffer_begin(struct lttng_kernel_ring_buffer *buf, u64 tsc,
  85                                 unsigned int subbuf_idx)
  86 {
  87         struct lttng_kernel_ring_buffer_channel *chan = buf->backend.chan;
  88         struct metadata_packet_header *header =
  89                 (struct metadata_packet_header *)
  90                         lib_ring_buffer_offset_address(&buf->backend,
  91                                 subbuf_idx * chan->backend.subbuf_size);
  92         struct lttng_metadata_cache *metadata_cache =
  93                 channel_get_private(chan);
  94
  95         header->magic = TSDL_MAGIC_NUMBER;
  96         memcpy(header->uuid, metadata_cache->uuid.b,
  97                 sizeof(metadata_cache->uuid));
  98         header->checksum = 0;           /* 0 if unused */
  99         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 100         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 101         header->compression_scheme = 0; /* 0 if unused */
 102         header->encryption_scheme = 0;  /* 0 if unused */
 103         header->checksum_scheme = 0;    /* 0 if unused */
 104         header->major = CTF_SPEC_MAJOR;
 105         header->minor = CTF_SPEC_MINOR;
 106 }
 107
 108 /*
 109  * offset is assumed to never be 0 here : never deliver a completely empty
 110  * subbuffer. data_size is between 1 and subbuf_size.
 111  */
 112 static void client_buffer_end(struct lttng_kernel_ring_buffer *buf, u64 tsc,
 113                               unsigned int subbuf_idx, unsigned long data_size,
 114                               const struct lttng_kernel_ring_buffer_ctx *ctx)
 115 {
 116         struct lttng_kernel_ring_buffer_channel *chan = buf->backend.chan;
 117         struct metadata_packet_header *header =
 118                 (struct metadata_packet_header *)
 119                         lib_ring_buffer_offset_address(&buf->backend,
 120                                 subbuf_idx * chan->backend.subbuf_size);
 121         unsigned long records_lost = 0;
 122
 123         header->content_size = data_size * CHAR_BIT;            /* in bits */
 124         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 125         /*
 126          * We do not care about the records lost count, because the metadata
 127          * channel waits and retry.
 128          */
 129         (void) lib_ring_buffer_get_records_lost_full(&client_config, ctx);
 130         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, ctx);
 131         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, ctx);
 132         WARN_ON_ONCE(records_lost != 0);
 133 }
 134
 135 static int client_buffer_create(struct lttng_kernel_ring_buffer *buf, void *priv,
 136                                 int cpu, const char *name)
 137 {
 138         return 0;
 139 }
 140
 141 static void client_buffer_finalize(struct lttng_kernel_ring_buffer *buf, void *priv, int cpu)
 142 {
 143 }
 144
 145 static int client_timestamp_begin(const struct lttng_kernel_ring_buffer_config *config,
 146                 struct lttng_kernel_ring_buffer *buf, uint64_t *timestamp_begin)
 147 {
 148         return -ENOSYS;
 149 }
 150
 151 static int client_timestamp_end(const struct lttng_kernel_ring_buffer_config *config,
 152                         struct lttng_kernel_ring_buffer *bufb,
 153                         uint64_t *timestamp_end)
 154 {
 155         return -ENOSYS;
 156 }
 157
 158 static int client_events_discarded(const struct lttng_kernel_ring_buffer_config *config,
 159                         struct lttng_kernel_ring_buffer *bufb,
 160                         uint64_t *events_discarded)
 161 {
 162         return -ENOSYS;
 163 }
 164
 165 static int client_current_timestamp(const struct lttng_kernel_ring_buffer_config *config,
 166                 struct lttng_kernel_ring_buffer *bufb,
 167                 uint64_t *ts)
 168 {
 169         return -ENOSYS;
 170 }
 171
 172 static int client_content_size(const struct lttng_kernel_ring_buffer_config *config,
 173                         struct lttng_kernel_ring_buffer *bufb,
 174                         uint64_t *content_size)
 175 {
 176         return -ENOSYS;
 177 }
 178
 179 static int client_packet_size(const struct lttng_kernel_ring_buffer_config *config,
 180                         struct lttng_kernel_ring_buffer *bufb,
 181                         uint64_t *packet_size)
 182 {
 183         return -ENOSYS;
 184 }
 185
 186 static int client_stream_id(const struct lttng_kernel_ring_buffer_config *config,
 187                         struct lttng_kernel_ring_buffer *bufb,
 188                         uint64_t *stream_id)
 189 {
 190         return -ENOSYS;
 191 }
 192
 193 static int client_sequence_number(const struct lttng_kernel_ring_buffer_config *config,
 194                         struct lttng_kernel_ring_buffer *bufb,
 195                         uint64_t *seq)
 196 {
 197         return -ENOSYS;
 198 }
 199
 200 static
 201 int client_instance_id(const struct lttng_kernel_ring_buffer_config *config,
 202                 struct lttng_kernel_ring_buffer *bufb,
 203                 uint64_t *id)
 204 {
 205         return -ENOSYS;
 206 }
 207
 208 static const struct lttng_kernel_ring_buffer_config client_config = {
 209         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 210         .cb.record_header_size = client_record_header_size,
 211         .cb.subbuffer_header_size = client_packet_header_size,
 212         .cb.buffer_begin = client_buffer_begin,
 213         .cb.buffer_end = client_buffer_end,
 214         .cb.buffer_create = client_buffer_create,
 215         .cb.buffer_finalize = client_buffer_finalize,
 216
 217         .tsc_bits = 0,
 218         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 219         .sync = RING_BUFFER_SYNC_GLOBAL,
 220         .mode = RING_BUFFER_MODE_TEMPLATE,
 221         .backend = RING_BUFFER_PAGE,
 222         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 223         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 224         .ipi = RING_BUFFER_IPI_BARRIER,
 225         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 226 };
 227
 228 static
 229 void release_priv_ops(void *priv_ops)
 230 {
 231         module_put(THIS_MODULE);
 232 }
 233
 234 static
 235 void lttng_channel_destroy(struct lttng_kernel_ring_buffer_channel *chan)
 236 {
 237         channel_destroy(chan);
 238 }
 239
 240 static
 241 struct lttng_kernel_ring_buffer_channel *_channel_create(const char *name,
 242                                 void *priv, void *buf_addr,
 243                                 size_t subbuf_size, size_t num_subbuf,
 244                                 unsigned int switch_timer_interval,
 245                                 unsigned int read_timer_interval)
 246 {
 247         struct lttng_kernel_channel_buffer *lttng_chan = priv;
 248         struct lttng_kernel_ring_buffer_channel *chan;
 249
 250         chan = channel_create(&client_config, name,
 251                               lttng_chan->parent.session->priv->metadata_cache, buf_addr,
 252                               subbuf_size, num_subbuf, switch_timer_interval,
 253                               read_timer_interval);
 254         if (chan) {
 255                 /*
 256                  * Ensure this module is not unloaded before we finish
 257                  * using lttng_relay_transport.ops.
 258                  */
 259                 if (!try_module_get(THIS_MODULE)) {
 260                         printk(KERN_WARNING "LTTng: Can't lock transport module.\n");
 261                         goto error;
 262                 }
 263                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 264                 chan->backend.release_priv_ops = release_priv_ops;
 265         }
 266         return chan;
 267
 268 error:
 269         lttng_channel_destroy(chan);
 270         return NULL;
 271 }
 272
 273 static
 274 struct lttng_kernel_ring_buffer *lttng_buffer_read_open(struct lttng_kernel_ring_buffer_channel *chan)
 275 {
 276         struct lttng_kernel_ring_buffer *buf;
 277
 278         buf = channel_get_ring_buffer(&client_config, chan, 0);
 279         if (!lib_ring_buffer_open_read(buf))
 280                 return buf;
 281         return NULL;
 282 }
 283
 284 static
 285 int lttng_buffer_has_read_closed_stream(struct lttng_kernel_ring_buffer_channel *chan)
 286 {
 287         struct lttng_kernel_ring_buffer *buf;
 288         int cpu;
 289
 290         for_each_channel_cpu(cpu, chan) {
 291                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 292                 if (!atomic_long_read(&buf->active_readers))
 293                         return 1;
 294         }
 295         return 0;
 296 }
 297
 298 static
 299 void lttng_buffer_read_close(struct lttng_kernel_ring_buffer *buf)
 300 {
 301         lib_ring_buffer_release_read(buf);
 302 }
 303
 304 static
 305 int lttng_event_reserve(struct lttng_kernel_ring_buffer_ctx *ctx)
 306 {
 307         struct lttng_kernel_ring_buffer_channel *chan = ctx->client_priv;
 308         int ret;
 309
 310         memset(&ctx->priv, 0, sizeof(ctx->priv));
 311         ctx->priv.chan = chan;
 312
 313         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 314         if (ret)
 315                 return ret;
 316         lib_ring_buffer_backend_get_pages(&client_config, ctx,
 317                         &ctx->priv.backend_pages);
 318         return 0;
 319
 320 }
 321
 322 static
 323 void lttng_event_commit(struct lttng_kernel_ring_buffer_ctx *ctx)
 324 {
 325         lib_ring_buffer_commit(&client_config, ctx);
 326 }
 327
 328 static
 329 void lttng_event_write(struct lttng_kernel_ring_buffer_ctx *ctx, const void *src,
 330                      size_t len, size_t alignment)
 331 {
 332         lib_ring_buffer_align_ctx(ctx, alignment);
 333         lib_ring_buffer_write(&client_config, ctx, src, len);
 334 }
 335
 336 static
 337 void lttng_event_write_from_user(struct lttng_kernel_ring_buffer_ctx *ctx,
 338                                const void __user *src, size_t len, size_t alignment)
 339 {
 340         lib_ring_buffer_align_ctx(ctx, alignment);
 341         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 342 }
 343
 344 static
 345 void lttng_event_memset(struct lttng_kernel_ring_buffer_ctx *ctx,
 346                 int c, size_t len)
 347 {
 348         lib_ring_buffer_memset(&client_config, ctx, c, len);
 349 }
 350
 351 static
 352 void lttng_event_strcpy(struct lttng_kernel_ring_buffer_ctx *ctx, const char *src,
 353                 size_t len)
 354 {
 355         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 356 }
 357
 358 static
 359 void lttng_event_pstrcpy_pad(struct lttng_kernel_ring_buffer_ctx *ctx, const char *src,
 360                 size_t len)
 361 {
 362         lib_ring_buffer_pstrcpy(&client_config, ctx, src, len, '\0');
 363 }
 364
 365 static
 366 size_t lttng_packet_avail_size(struct lttng_kernel_ring_buffer_channel *chan)
 367 {
 368         unsigned long o_begin;
 369         struct lttng_kernel_ring_buffer *buf;
 370
 371         buf = chan->backend.buf;        /* Only for global buffer ! */
 372         o_begin = v_read(&client_config, &buf->offset);
 373         if (subbuf_offset(o_begin, chan) != 0) {
 374                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 375         } else {
 376                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 377                         - sizeof(struct metadata_packet_header);
 378         }
 379 }
 380
 381 static
 382 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct lttng_kernel_ring_buffer_channel *chan, int cpu)
 383 {
 384         struct lttng_kernel_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 385                                         chan, cpu);
 386         return &buf->write_wait;
 387 }
 388
 389 static
 390 wait_queue_head_t *lttng_get_hp_wait_queue(struct lttng_kernel_ring_buffer_channel *chan)
 391 {
 392         return &chan->hp_wait;
 393 }
 394
 395 static
 396 int lttng_is_finalized(struct lttng_kernel_ring_buffer_channel *chan)
 397 {
 398         return lib_ring_buffer_channel_is_finalized(chan);
 399 }
 400
 401 static
 402 int lttng_is_disabled(struct lttng_kernel_ring_buffer_channel *chan)
 403 {
 404         return lib_ring_buffer_channel_is_disabled(chan);
 405 }
 406
 407 static struct lttng_transport lttng_relay_transport = {
 408         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 409         .owner = THIS_MODULE,
 410         .ops = {
 411                 .priv = __LTTNG_COMPOUND_LITERAL(struct lttng_kernel_channel_buffer_ops_private, {
 412                         .pub = &lttng_relay_transport.ops,
 413                         .channel_create = _channel_create,
 414                         .channel_destroy = lttng_channel_destroy,
 415                         .buffer_read_open = lttng_buffer_read_open,
 416                         .buffer_has_read_closed_stream =
 417                                 lttng_buffer_has_read_closed_stream,
 418                         .buffer_read_close = lttng_buffer_read_close,
 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                 .event_reserve = lttng_event_reserve,
 435                 .event_commit = lttng_event_commit,
 436                 .event_write_from_user = lttng_event_write_from_user,
 437                 .event_memset = lttng_event_memset,
 438                 .event_write = lttng_event_write,
 439                 .event_strcpy = lttng_event_strcpy,
 440                 .event_pstrcpy_pad = lttng_event_pstrcpy_pad,
 441         },
 442 };
 443
 444 static int __init lttng_ring_buffer_client_init(void)
 445 {
 446         /*
 447          * This vmalloc sync all also takes care of the lib ring buffer
 448          * vmalloc'd module pages when it is built as a module into LTTng.
 449          */
 450         wrapper_vmalloc_sync_mappings();
 451         lttng_transport_register(&lttng_relay_transport);
 452         return 0;
 453 }
 454
 455 module_init(lttng_ring_buffer_client_init);
 456
 457 static void __exit lttng_ring_buffer_client_exit(void)
 458 {
 459         lttng_transport_unregister(&lttng_relay_transport);
 460 }
 461
 462 module_exit(lttng_ring_buffer_client_exit);
 463
 464 MODULE_LICENSE("GPL and additional rights");
 465 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
 466 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 467                    " client");
 468 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 469         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 470         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 471         LTTNG_MODULES_EXTRAVERSION);