lttng-ring-buffer-metadata-client.h

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   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_all() */
  13 #include <lttng-events.h>
  14 #include <lttng-tracer.h>
  15
  16 static struct lttng_transport lttng_relay_transport;
  17
  18 struct metadata_packet_header {
  19         uint32_t magic;                 /* 0x75D11D57 */
  20         uint8_t  uuid[16];              /* Unique Universal Identifier */
  21         uint32_t checksum;              /* 0 if unused */
  22         uint32_t content_size;          /* in bits */
  23         uint32_t packet_size;           /* in bits */
  24         uint8_t  compression_scheme;    /* 0 if unused */
  25         uint8_t  encryption_scheme;     /* 0 if unused */
  26         uint8_t  checksum_scheme;       /* 0 if unused */
  27         uint8_t  major;                 /* CTF spec major version number */
  28         uint8_t  minor;                 /* CTF spec minor version number */
  29         uint8_t  header_end[0];
  30 };
  31
  32 struct metadata_record_header {
  33         uint8_t header_end[0];          /* End of header */
  34 };
  35
  36 static const struct lib_ring_buffer_config client_config;
  37
  38 static inline
  39 u64 lib_ring_buffer_clock_read(struct channel *chan)
  40 {
  41         return 0;
  42 }
  43
  44 static inline
  45 size_t record_header_size(const struct lib_ring_buffer_config *config,
  46                                  struct channel *chan, size_t offset,
  47                                  size_t *pre_header_padding,
  48                                  struct lib_ring_buffer_ctx *ctx,
  49                                  void *client_ctx)
  50 {
  51         return 0;
  52 }
  53
  54 #include <wrapper/ringbuffer/api.h>
  55
  56 static u64 client_ring_buffer_clock_read(struct channel *chan)
  57 {
  58         return 0;
  59 }
  60
  61 static
  62 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  63                                  struct channel *chan, size_t offset,
  64                                  size_t *pre_header_padding,
  65                                  struct lib_ring_buffer_ctx *ctx,
  66                                  void *client_ctx)
  67 {
  68         return 0;
  69 }
  70
  71 /**
  72  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  73  *
  74  * Return header size without padding after the structure. Don't use packed
  75  * structure because gcc generates inefficient code on some architectures
  76  * (powerpc, mips..)
  77  */
  78 static size_t client_packet_header_size(void)
  79 {
  80         return offsetof(struct metadata_packet_header, header_end);
  81 }
  82
  83 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  84                                 unsigned int subbuf_idx)
  85 {
  86         struct channel *chan = buf->backend.chan;
  87         struct metadata_packet_header *header =
  88                 (struct metadata_packet_header *)
  89                         lib_ring_buffer_offset_address(&buf->backend,
  90                                 subbuf_idx * chan->backend.subbuf_size);
  91         struct lttng_metadata_cache *metadata_cache =
  92                 channel_get_private(chan);
  93
  94         header->magic = TSDL_MAGIC_NUMBER;
  95         memcpy(header->uuid, metadata_cache->uuid.b,
  96                 sizeof(metadata_cache->uuid));
  97         header->checksum = 0;           /* 0 if unused */
  98         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  99         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 100         header->compression_scheme = 0; /* 0 if unused */
 101         header->encryption_scheme = 0;  /* 0 if unused */
 102         header->checksum_scheme = 0;    /* 0 if unused */
 103         header->major = CTF_SPEC_MAJOR;
 104         header->minor = CTF_SPEC_MINOR;
 105 }
 106
 107 /*
 108  * offset is assumed to never be 0 here : never deliver a completely empty
 109  * subbuffer. data_size is between 1 and subbuf_size.
 110  */
 111 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 112                               unsigned int subbuf_idx, unsigned long data_size)
 113 {
 114         struct channel *chan = buf->backend.chan;
 115         struct metadata_packet_header *header =
 116                 (struct metadata_packet_header *)
 117                         lib_ring_buffer_offset_address(&buf->backend,
 118                                 subbuf_idx * chan->backend.subbuf_size);
 119         unsigned long records_lost = 0;
 120
 121         header->content_size = data_size * CHAR_BIT;            /* in bits */
 122         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 123         /*
 124          * We do not care about the records lost count, because the metadata
 125          * channel waits and retry.
 126          */
 127         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 128         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 129         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 130         WARN_ON_ONCE(records_lost != 0);
 131 }
 132
 133 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 134                                 int cpu, const char *name)
 135 {
 136         return 0;
 137 }
 138
 139 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 140 {
 141 }
 142
 143 static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
 144                 struct lib_ring_buffer *buf, uint64_t *timestamp_begin)
 145 {
 146         return -ENOSYS;
 147 }
 148
 149 static int client_timestamp_end(const struct lib_ring_buffer_config *config,
 150                         struct lib_ring_buffer *bufb,
 151                         uint64_t *timestamp_end)
 152 {
 153         return -ENOSYS;
 154 }
 155
 156 static int client_events_discarded(const struct lib_ring_buffer_config *config,
 157                         struct lib_ring_buffer *bufb,
 158                         uint64_t *events_discarded)
 159 {
 160         return -ENOSYS;
 161 }
 162
 163 static int client_current_timestamp(const struct lib_ring_buffer_config *config,
 164                 struct lib_ring_buffer *bufb,
 165                 uint64_t *ts)
 166 {
 167         return -ENOSYS;
 168 }
 169
 170 static int client_content_size(const struct lib_ring_buffer_config *config,
 171                         struct lib_ring_buffer *bufb,
 172                         uint64_t *content_size)
 173 {
 174         return -ENOSYS;
 175 }
 176
 177 static int client_packet_size(const struct lib_ring_buffer_config *config,
 178                         struct lib_ring_buffer *bufb,
 179                         uint64_t *packet_size)
 180 {
 181         return -ENOSYS;
 182 }
 183
 184 static int client_stream_id(const struct lib_ring_buffer_config *config,
 185                         struct lib_ring_buffer *bufb,
 186                         uint64_t *stream_id)
 187 {
 188         return -ENOSYS;
 189 }
 190
 191 static int client_sequence_number(const struct lib_ring_buffer_config *config,
 192                         struct lib_ring_buffer *bufb,
 193                         uint64_t *seq)
 194 {
 195         return -ENOSYS;
 196 }
 197
 198 static
 199 int client_instance_id(const struct lib_ring_buffer_config *config,
 200                 struct lib_ring_buffer *bufb,
 201                 uint64_t *id)
 202 {
 203         return -ENOSYS;
 204 }
 205
 206 static const struct lib_ring_buffer_config client_config = {
 207         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 208         .cb.record_header_size = client_record_header_size,
 209         .cb.subbuffer_header_size = client_packet_header_size,
 210         .cb.buffer_begin = client_buffer_begin,
 211         .cb.buffer_end = client_buffer_end,
 212         .cb.buffer_create = client_buffer_create,
 213         .cb.buffer_finalize = client_buffer_finalize,
 214
 215         .tsc_bits = 0,
 216         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 217         .sync = RING_BUFFER_SYNC_GLOBAL,
 218         .mode = RING_BUFFER_MODE_TEMPLATE,
 219         .backend = RING_BUFFER_PAGE,
 220         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 221         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 222         .ipi = RING_BUFFER_IPI_BARRIER,
 223         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 224 };
 225
 226 static
 227 void release_priv_ops(void *priv_ops)
 228 {
 229         module_put(THIS_MODULE);
 230 }
 231
 232 static
 233 void lttng_channel_destroy(struct channel *chan)
 234 {
 235         channel_destroy(chan);
 236 }
 237
 238 static
 239 struct channel *_channel_create(const char *name,
 240                                 void *priv, void *buf_addr,
 241                                 size_t subbuf_size, size_t num_subbuf,
 242                                 unsigned int switch_timer_interval,
 243                                 unsigned int read_timer_interval)
 244 {
 245         struct lttng_channel *lttng_chan = priv;
 246         struct channel *chan;
 247
 248         chan = channel_create(&client_config, name,
 249                               lttng_chan->session->metadata_cache, buf_addr,
 250                               subbuf_size, num_subbuf, switch_timer_interval,
 251                               read_timer_interval);
 252         if (chan) {
 253                 /*
 254                  * Ensure this module is not unloaded before we finish
 255                  * using lttng_relay_transport.ops.
 256                  */
 257                 if (!try_module_get(THIS_MODULE)) {
 258                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 259                         goto error;
 260                 }
 261                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 262                 chan->backend.release_priv_ops = release_priv_ops;
 263         }
 264         return chan;
 265
 266 error:
 267         lttng_channel_destroy(chan);
 268         return NULL;
 269 }
 270
 271 static
 272 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 273 {
 274         struct lib_ring_buffer *buf;
 275
 276         buf = channel_get_ring_buffer(&client_config, chan, 0);
 277         if (!lib_ring_buffer_open_read(buf))
 278                 return buf;
 279         return NULL;
 280 }
 281
 282 static
 283 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 284 {
 285         struct lib_ring_buffer *buf;
 286         int cpu;
 287
 288         for_each_channel_cpu(cpu, chan) {
 289                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 290                 if (!atomic_long_read(&buf->active_readers))
 291                         return 1;
 292         }
 293         return 0;
 294 }
 295
 296 static
 297 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 298 {
 299         lib_ring_buffer_release_read(buf);
 300 }
 301
 302 static
 303 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 304 {
 305         int ret;
 306
 307         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 308         if (ret)
 309                 return ret;
 310         lib_ring_buffer_backend_get_pages(&client_config, ctx,
 311                         &ctx->backend_pages);
 312         return 0;
 313
 314 }
 315
 316 static
 317 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 318 {
 319         lib_ring_buffer_commit(&client_config, ctx);
 320 }
 321
 322 static
 323 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 324                      size_t len)
 325 {
 326         lib_ring_buffer_write(&client_config, ctx, src, len);
 327 }
 328
 329 static
 330 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 331                                const void __user *src, size_t len)
 332 {
 333         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 334 }
 335
 336 static
 337 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 338                 int c, size_t len)
 339 {
 340         lib_ring_buffer_memset(&client_config, ctx, c, len);
 341 }
 342
 343 static
 344 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 345                 size_t len)
 346 {
 347         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 348 }
 349
 350 static
 351 size_t lttng_packet_avail_size(struct channel *chan)
 352
 353 {
 354         unsigned long o_begin;
 355         struct lib_ring_buffer *buf;
 356
 357         buf = chan->backend.buf;        /* Only for global buffer ! */
 358         o_begin = v_read(&client_config, &buf->offset);
 359         if (subbuf_offset(o_begin, chan) != 0) {
 360                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 361         } else {
 362                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 363                         - sizeof(struct metadata_packet_header);
 364         }
 365 }
 366
 367 static
 368 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 369 {
 370         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 371                                         chan, cpu);
 372         return &buf->write_wait;
 373 }
 374
 375 static
 376 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 377 {
 378         return &chan->hp_wait;
 379 }
 380
 381 static
 382 int lttng_is_finalized(struct channel *chan)
 383 {
 384         return lib_ring_buffer_channel_is_finalized(chan);
 385 }
 386
 387 static
 388 int lttng_is_disabled(struct channel *chan)
 389 {
 390         return lib_ring_buffer_channel_is_disabled(chan);
 391 }
 392
 393 static struct lttng_transport lttng_relay_transport = {
 394         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 395         .owner = THIS_MODULE,
 396         .ops = {
 397                 .channel_create = _channel_create,
 398                 .channel_destroy = lttng_channel_destroy,
 399                 .buffer_read_open = lttng_buffer_read_open,
 400                 .buffer_has_read_closed_stream =
 401                         lttng_buffer_has_read_closed_stream,
 402                 .buffer_read_close = lttng_buffer_read_close,
 403                 .event_reserve = lttng_event_reserve,
 404                 .event_commit = lttng_event_commit,
 405                 .event_write_from_user = lttng_event_write_from_user,
 406                 .event_memset = lttng_event_memset,
 407                 .event_write = lttng_event_write,
 408                 .event_strcpy = lttng_event_strcpy,
 409                 .packet_avail_size = lttng_packet_avail_size,
 410                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 411                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 412                 .is_finalized = lttng_is_finalized,
 413                 .is_disabled = lttng_is_disabled,
 414                 .timestamp_begin = client_timestamp_begin,
 415                 .timestamp_end = client_timestamp_end,
 416                 .events_discarded = client_events_discarded,
 417                 .content_size = client_content_size,
 418                 .packet_size = client_packet_size,
 419                 .stream_id = client_stream_id,
 420                 .current_timestamp = client_current_timestamp,
 421                 .sequence_number = client_sequence_number,
 422                 .instance_id = client_instance_id,
 423         },
 424 };
 425
 426 static int __init lttng_ring_buffer_client_init(void)
 427 {
 428         /*
 429          * This vmalloc sync all also takes care of the lib ring buffer
 430          * vmalloc'd module pages when it is built as a module into LTTng.
 431          */
 432         wrapper_vmalloc_sync_all();
 433         lttng_transport_register(&lttng_relay_transport);
 434         return 0;
 435 }
 436
 437 module_init(lttng_ring_buffer_client_init);
 438
 439 static void __exit lttng_ring_buffer_client_exit(void)
 440 {
 441         lttng_transport_unregister(&lttng_relay_transport);
 442 }
 443
 444 module_exit(lttng_ring_buffer_client_exit);
 445
 446 MODULE_LICENSE("GPL and additional rights");
 447 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
 448 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 449                    " client");
 450 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 451         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 452         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 453         LTTNG_MODULES_EXTRAVERSION);