lttng-ring-buffer-trigger-client.h

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * lttng-ring-buffer-trigger-client.h
   4  *
   5  * LTTng lib ring buffer trigger client template.
   6  *
   7  * Copyright (C) 2010-2020 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 trigger_packet_header {
  19         uint32_t magic;                 /* 0x75D11D57 */
  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 trigger_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 <wrapper/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 trigger_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 trigger_packet_header *header =
  87                 (struct trigger_packet_header *)
  88                         lib_ring_buffer_offset_address(&buf->backend,
  89                                 subbuf_idx * chan->backend.subbuf_size);
  90
  91         header->magic = TSDL_MAGIC_NUMBER;
  92         header->checksum = 0;           /* 0 if unused */
  93         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  94         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  95         header->compression_scheme = 0; /* 0 if unused */
  96         header->encryption_scheme = 0;  /* 0 if unused */
  97         header->checksum_scheme = 0;    /* 0 if unused */
  98         header->major = CTF_SPEC_MAJOR;
  99         header->minor = CTF_SPEC_MINOR;
 100 }
 101
 102 /*
 103  * offset is assumed to never be 0 here : never deliver a completely empty
 104  * subbuffer. data_size is between 1 and subbuf_size.
 105  */
 106 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 107                               unsigned int subbuf_idx, unsigned long data_size)
 108 {
 109         struct channel *chan = buf->backend.chan;
 110         struct trigger_packet_header *header =
 111                 (struct trigger_packet_header *)
 112                         lib_ring_buffer_offset_address(&buf->backend,
 113                                 subbuf_idx * chan->backend.subbuf_size);
 114         unsigned long records_lost = 0;
 115
 116         header->content_size = data_size * CHAR_BIT;            /* in bits */
 117         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 118         /*
 119          * We do not care about the records lost count, because the trigger
 120          * channel waits and retry.
 121          */
 122         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 123         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 124         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 125         WARN_ON_ONCE(records_lost != 0);
 126 }
 127
 128 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 129                                 int cpu, const char *name)
 130 {
 131         return 0;
 132 }
 133
 134 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 135 {
 136 }
 137
 138 static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
 139                 struct lib_ring_buffer *buf, uint64_t *timestamp_begin)
 140 {
 141         return -ENOSYS;
 142 }
 143
 144 static int client_timestamp_end(const struct lib_ring_buffer_config *config,
 145                         struct lib_ring_buffer *bufb,
 146                         uint64_t *timestamp_end)
 147 {
 148         return -ENOSYS;
 149 }
 150
 151 static int client_events_discarded(const struct lib_ring_buffer_config *config,
 152                         struct lib_ring_buffer *bufb,
 153                         uint64_t *events_discarded)
 154 {
 155         return -ENOSYS;
 156 }
 157
 158 static int client_current_timestamp(const struct lib_ring_buffer_config *config,
 159                 struct lib_ring_buffer *bufb,
 160                 uint64_t *ts)
 161 {
 162         return -ENOSYS;
 163 }
 164
 165 static int client_content_size(const struct lib_ring_buffer_config *config,
 166                         struct lib_ring_buffer *bufb,
 167                         uint64_t *content_size)
 168 {
 169         return -ENOSYS;
 170 }
 171
 172 static int client_packet_size(const struct lib_ring_buffer_config *config,
 173                         struct lib_ring_buffer *bufb,
 174                         uint64_t *packet_size)
 175 {
 176         return -ENOSYS;
 177 }
 178
 179 static int client_stream_id(const struct lib_ring_buffer_config *config,
 180                         struct lib_ring_buffer *bufb,
 181                         uint64_t *stream_id)
 182 {
 183         return -ENOSYS;
 184 }
 185
 186 static int client_sequence_number(const struct lib_ring_buffer_config *config,
 187                         struct lib_ring_buffer *bufb,
 188                         uint64_t *seq)
 189 {
 190         return -ENOSYS;
 191 }
 192
 193 static
 194 int client_instance_id(const struct lib_ring_buffer_config *config,
 195                 struct lib_ring_buffer *bufb,
 196                 uint64_t *id)
 197 {
 198         return -ENOSYS;
 199 }
 200
 201 static void client_record_get(const struct lib_ring_buffer_config *config,
 202         struct channel *chan, struct lib_ring_buffer *buf,
 203         size_t offset, size_t *header_len,
 204         size_t *payload_len, u64 *timestamp)
 205 {
 206         struct trigger_record_header header;
 207         int ret;
 208
 209         ret = lib_ring_buffer_read(&buf->backend, offset, &header,
 210                         offsetof(struct trigger_record_header, header_end));
 211         CHAN_WARN_ON(chan, ret != offsetof(struct trigger_record_header, header_end));
 212         *header_len = offsetof(struct trigger_record_header, header_end);
 213         /*
 214          * Currently, only 64-bit trigger ID.
 215          */
 216         *payload_len = sizeof(uint64_t);
 217         *timestamp = 0;
 218 }
 219
 220 static const struct lib_ring_buffer_config client_config = {
 221         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 222         .cb.record_header_size = client_record_header_size,
 223         .cb.subbuffer_header_size = client_packet_header_size,
 224         .cb.buffer_begin = client_buffer_begin,
 225         .cb.buffer_end = client_buffer_end,
 226         .cb.buffer_create = client_buffer_create,
 227         .cb.buffer_finalize = client_buffer_finalize,
 228         .cb.record_get = client_record_get,
 229
 230         .tsc_bits = 0,
 231         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 232         .sync = RING_BUFFER_SYNC_GLOBAL,
 233         .mode = RING_BUFFER_MODE_TEMPLATE,
 234         .backend = RING_BUFFER_PAGE,
 235         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 236         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 237         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 238         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 239 };
 240
 241 static
 242 void release_priv_ops(void *priv_ops)
 243 {
 244         module_put(THIS_MODULE);
 245 }
 246
 247 static
 248 void lttng_channel_destroy(struct channel *chan)
 249 {
 250         channel_destroy(chan);
 251 }
 252
 253 static
 254 struct channel *_channel_create(const char *name,
 255                                 void *priv, void *buf_addr,
 256                                 size_t subbuf_size, size_t num_subbuf,
 257                                 unsigned int switch_timer_interval,
 258                                 unsigned int read_timer_interval)
 259 {
 260         struct lttng_trigger_group *trigger_group = priv;
 261         struct channel *chan;
 262
 263         chan = channel_create(&client_config, name,
 264                               trigger_group, buf_addr,
 265                               subbuf_size, num_subbuf, switch_timer_interval,
 266                               read_timer_interval);
 267         if (chan) {
 268                 /*
 269                  * Ensure this module is not unloaded before we finish
 270                  * using lttng_relay_transport.ops.
 271                  */
 272                 if (!try_module_get(THIS_MODULE)) {
 273                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 274                         goto error;
 275                 }
 276                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 277                 chan->backend.release_priv_ops = release_priv_ops;
 278         }
 279         return chan;
 280
 281 error:
 282         lttng_channel_destroy(chan);
 283         return NULL;
 284 }
 285
 286 static
 287 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 288 {
 289         struct lib_ring_buffer *buf;
 290
 291         buf = channel_get_ring_buffer(&client_config, chan, 0);
 292         if (!lib_ring_buffer_open_read(buf))
 293                 return buf;
 294         return NULL;
 295 }
 296
 297 static
 298 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 299 {
 300         struct lib_ring_buffer *buf;
 301         int cpu;
 302
 303         for_each_channel_cpu(cpu, chan) {
 304                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 305                 if (!atomic_long_read(&buf->active_readers))
 306                         return 1;
 307         }
 308         return 0;
 309 }
 310
 311 static
 312 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 313 {
 314         lib_ring_buffer_release_read(buf);
 315 }
 316
 317 static
 318 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 319 {
 320         int ret;
 321
 322         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 323         if (ret)
 324                 return ret;
 325         lib_ring_buffer_backend_get_pages(&client_config, ctx,
 326                         &ctx->backend_pages);
 327         return 0;
 328 }
 329
 330 static
 331 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 332 {
 333         lib_ring_buffer_commit(&client_config, ctx);
 334 }
 335
 336 static
 337 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 338                      size_t len)
 339 {
 340         lib_ring_buffer_write(&client_config, ctx, src, len);
 341 }
 342
 343 static
 344 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 345                                const void __user *src, size_t len)
 346 {
 347         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 348 }
 349
 350 static
 351 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 352                 int c, size_t len)
 353 {
 354         lib_ring_buffer_memset(&client_config, ctx, c, len);
 355 }
 356
 357 static
 358 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 359                 size_t len)
 360 {
 361         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 362 }
 363
 364 static
 365 size_t lttng_packet_avail_size(struct channel *chan)
 366 {
 367         unsigned long o_begin;
 368         struct lib_ring_buffer *buf;
 369
 370         buf = chan->backend.buf;        /* Only for global buffer ! */
 371         o_begin = v_read(&client_config, &buf->offset);
 372         if (subbuf_offset(o_begin, chan) != 0) {
 373                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 374         } else {
 375                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 376                         - sizeof(struct trigger_packet_header);
 377         }
 378 }
 379
 380 static
 381 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 382 {
 383         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 384                                         chan, cpu);
 385         return &buf->write_wait;
 386 }
 387
 388 static
 389 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 390 {
 391         return &chan->hp_wait;
 392 }
 393
 394 static
 395 int lttng_is_finalized(struct channel *chan)
 396 {
 397         return lib_ring_buffer_channel_is_finalized(chan);
 398 }
 399
 400 static
 401 int lttng_is_disabled(struct channel *chan)
 402 {
 403         return lib_ring_buffer_channel_is_disabled(chan);
 404 }
 405
 406 static struct lttng_transport lttng_relay_transport = {
 407         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 408         .owner = THIS_MODULE,
 409         .ops = {
 410                 .channel_create = _channel_create,
 411                 .channel_destroy = lttng_channel_destroy,
 412                 .buffer_read_open = lttng_buffer_read_open,
 413                 .buffer_has_read_closed_stream =
 414                         lttng_buffer_has_read_closed_stream,
 415                 .buffer_read_close = lttng_buffer_read_close,
 416                 .event_reserve = lttng_event_reserve,
 417                 .event_commit = lttng_event_commit,
 418                 .event_write_from_user = lttng_event_write_from_user,
 419                 .event_memset = lttng_event_memset,
 420                 .event_write = lttng_event_write,
 421                 .event_strcpy = lttng_event_strcpy,
 422                 .packet_avail_size = lttng_packet_avail_size,
 423                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 424                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 425                 .is_finalized = lttng_is_finalized,
 426                 .is_disabled = lttng_is_disabled,
 427                 .timestamp_begin = client_timestamp_begin,
 428                 .timestamp_end = client_timestamp_end,
 429                 .events_discarded = client_events_discarded,
 430                 .content_size = client_content_size,
 431                 .packet_size = client_packet_size,
 432                 .stream_id = client_stream_id,
 433                 .current_timestamp = client_current_timestamp,
 434                 .sequence_number = client_sequence_number,
 435                 .instance_id = client_instance_id,
 436         },
 437 };
 438
 439 static int __init lttng_ring_buffer_trigger_client_init(void)
 440 {
 441         /*
 442          * This vmalloc sync all also takes care of the lib ring buffer
 443          * vmalloc'd module pages when it is built as a module into LTTng.
 444          */
 445         wrapper_vmalloc_sync_all();
 446         lttng_transport_register(&lttng_relay_transport);
 447         return 0;
 448 }
 449
 450 module_init(lttng_ring_buffer_trigger_client_init);
 451
 452 static void __exit lttng_ring_buffer_trigger_client_exit(void)
 453 {
 454         lttng_transport_unregister(&lttng_relay_transport);
 455 }
 456
 457 module_exit(lttng_ring_buffer_trigger_client_exit);
 458
 459 MODULE_LICENSE("GPL and additional rights");
 460 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
 461 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 462                    " client");
 463 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 464         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 465         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 466         LTTNG_MODULES_EXTRAVERSION);