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