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