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                                 struct lttng_channel *lttng_chan, 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 channel *chan;
 246
 247         chan = channel_create(&client_config, name,
 248                               lttng_chan->session->metadata_cache, buf_addr,
 249                               subbuf_size, num_subbuf, switch_timer_interval,
 250                               read_timer_interval);
 251         if (chan) {
 252                 /*
 253                  * Ensure this module is not unloaded before we finish
 254                  * using lttng_relay_transport.ops.
 255                  */
 256                 if (!try_module_get(THIS_MODULE)) {
 257                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 258                         goto error;
 259                 }
 260                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 261                 chan->backend.release_priv_ops = release_priv_ops;
 262         }
 263         return chan;
 264
 265 error:
 266         lttng_channel_destroy(chan);
 267         return NULL;
 268 }
 269
 270 static
 271 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 272 {
 273         struct lib_ring_buffer *buf;
 274
 275         buf = channel_get_ring_buffer(&client_config, chan, 0);
 276         if (!lib_ring_buffer_open_read(buf))
 277                 return buf;
 278         return NULL;
 279 }
 280
 281 static
 282 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 283 {
 284         struct lib_ring_buffer *buf;
 285         int cpu;
 286
 287         for_each_channel_cpu(cpu, chan) {
 288                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 289                 if (!atomic_long_read(&buf->active_readers))
 290                         return 1;
 291         }
 292         return 0;
 293 }
 294
 295 static
 296 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 297 {
 298         lib_ring_buffer_release_read(buf);
 299 }
 300
 301 static
 302 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 303 {
 304         int ret;
 305
 306         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 307         if (ret)
 308                 return ret;
 309         lib_ring_buffer_backend_get_pages(&client_config, ctx,
 310                         &ctx->backend_pages);
 311         return 0;
 312
 313 }
 314
 315 static
 316 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 317 {
 318         lib_ring_buffer_commit(&client_config, ctx);
 319 }
 320
 321 static
 322 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 323                      size_t len)
 324 {
 325         lib_ring_buffer_write(&client_config, ctx, src, len);
 326 }
 327
 328 static
 329 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 330                                const void __user *src, size_t len)
 331 {
 332         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 333 }
 334
 335 static
 336 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 337                 int c, size_t len)
 338 {
 339         lib_ring_buffer_memset(&client_config, ctx, c, len);
 340 }
 341
 342 static
 343 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 344                 size_t len)
 345 {
 346         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 347 }
 348
 349 static
 350 size_t lttng_packet_avail_size(struct channel *chan)
 351
 352 {
 353         unsigned long o_begin;
 354         struct lib_ring_buffer *buf;
 355
 356         buf = chan->backend.buf;        /* Only for global buffer ! */
 357         o_begin = v_read(&client_config, &buf->offset);
 358         if (subbuf_offset(o_begin, chan) != 0) {
 359                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 360         } else {
 361                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 362                         - sizeof(struct metadata_packet_header);
 363         }
 364 }
 365
 366 static
 367 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 368 {
 369         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 370                                         chan, cpu);
 371         return &buf->write_wait;
 372 }
 373
 374 static
 375 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 376 {
 377         return &chan->hp_wait;
 378 }
 379
 380 static
 381 int lttng_is_finalized(struct channel *chan)
 382 {
 383         return lib_ring_buffer_channel_is_finalized(chan);
 384 }
 385
 386 static
 387 int lttng_is_disabled(struct channel *chan)
 388 {
 389         return lib_ring_buffer_channel_is_disabled(chan);
 390 }
 391
 392 static struct lttng_transport lttng_relay_transport = {
 393         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 394         .owner = THIS_MODULE,
 395         .ops = {
 396                 .channel_create = _channel_create,
 397                 .channel_destroy = lttng_channel_destroy,
 398                 .buffer_read_open = lttng_buffer_read_open,
 399                 .buffer_has_read_closed_stream =
 400                         lttng_buffer_has_read_closed_stream,
 401                 .buffer_read_close = lttng_buffer_read_close,
 402                 .event_reserve = lttng_event_reserve,
 403                 .event_commit = lttng_event_commit,
 404                 .event_write_from_user = lttng_event_write_from_user,
 405                 .event_memset = lttng_event_memset,
 406                 .event_write = lttng_event_write,
 407                 .event_strcpy = lttng_event_strcpy,
 408                 .packet_avail_size = lttng_packet_avail_size,
 409                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 410                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 411                 .is_finalized = lttng_is_finalized,
 412                 .is_disabled = lttng_is_disabled,
 413                 .timestamp_begin = client_timestamp_begin,
 414                 .timestamp_end = client_timestamp_end,
 415                 .events_discarded = client_events_discarded,
 416                 .content_size = client_content_size,
 417                 .packet_size = client_packet_size,
 418                 .stream_id = client_stream_id,
 419                 .current_timestamp = client_current_timestamp,
 420                 .sequence_number = client_sequence_number,
 421                 .instance_id = client_instance_id,
 422         },
 423 };
 424
 425 static int __init lttng_ring_buffer_client_init(void)
 426 {
 427         /*
 428          * This vmalloc sync all also takes care of the lib ring buffer
 429          * vmalloc'd module pages when it is built as a module into LTTng.
 430          */
 431         wrapper_vmalloc_sync_all();
 432         lttng_transport_register(&lttng_relay_transport);
 433         return 0;
 434 }
 435
 436 module_init(lttng_ring_buffer_client_init);
 437
 438 static void __exit lttng_ring_buffer_client_exit(void)
 439 {
 440         lttng_transport_unregister(&lttng_relay_transport);
 441 }
 442
 443 module_exit(lttng_ring_buffer_client_exit);
 444
 445 MODULE_LICENSE("GPL and additional rights");
 446 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
 447 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 448                    " client");
 449 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 450         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 451         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 452         LTTNG_MODULES_EXTRAVERSION);