src/common/ringbuffer-clients/metadata-template.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  */
   8
   9 #include <limits.h>
  10 #include <stddef.h>
  11 #include <stdint.h>
  12
  13 #include <urcu/tls-compat.h>
  14
  15 #include "common/bitfield.h"
  16 #include "common/align.h"
  17 #include "common/events.h"
  18 #include "common/tracer.h"
  19 #include "common/ringbuffer/frontend_types.h"
  20
  21 struct metadata_packet_header {
  22         uint32_t magic;                 /* 0x75D11D57 */
  23         uint8_t  uuid[LTTNG_UST_UUID_LEN]; /* Unique Universal Identifier */
  24         uint32_t checksum;              /* 0 if unused */
  25         uint32_t content_size;          /* in bits */
  26         uint32_t packet_size;           /* in bits */
  27         uint8_t  compression_scheme;    /* 0 if unused */
  28         uint8_t  encryption_scheme;     /* 0 if unused */
  29         uint8_t  checksum_scheme;       /* 0 if unused */
  30         uint8_t  major;                 /* CTF spec major version number */
  31         uint8_t  minor;                 /* CTF spec minor version number */
  32         uint8_t  header_end[0];
  33 };
  34
  35 struct metadata_record_header {
  36         uint8_t header_end[0];          /* End of header */
  37 };
  38
  39 static const struct lttng_ust_ring_buffer_config client_config;
  40
  41 /* No nested use supported for metadata ring buffer. */
  42 static DEFINE_URCU_TLS(struct lttng_ust_ring_buffer_ctx_private, private_ctx);
  43
  44 static inline uint64_t lib_ring_buffer_clock_read(
  45                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)))
  46 {
  47         return 0;
  48 }
  49
  50 static inline
  51 size_t record_header_size(
  52                 const struct lttng_ust_ring_buffer_config *config __attribute__((unused)),
  53                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)),
  54                 size_t offset __attribute__((unused)),
  55                 size_t *pre_header_padding __attribute__((unused)),
  56                 struct lttng_ust_ring_buffer_ctx *ctx __attribute__((unused)),
  57                 void *client_ctx __attribute__((unused)))
  58 {
  59         return 0;
  60 }
  61
  62 #include "common/ringbuffer/api.h"
  63 #include "common/ringbuffer-clients/clients.h"
  64
  65 static uint64_t client_ring_buffer_clock_read(
  66                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)))
  67 {
  68         return 0;
  69 }
  70
  71 static
  72 size_t client_record_header_size(
  73                 const struct lttng_ust_ring_buffer_config *config __attribute__((unused)),
  74                 struct lttng_ust_ring_buffer_channel *chan __attribute__((unused)),
  75                 size_t offset __attribute__((unused)),
  76                 size_t *pre_header_padding __attribute__((unused)),
  77                 struct lttng_ust_ring_buffer_ctx *ctx __attribute__((unused)),
  78                 void *client_ctx __attribute__((unused)))
  79 {
  80         return 0;
  81 }
  82
  83 /**
  84  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  85  *
  86  * Return header size without padding after the structure. Don't use packed
  87  * structure because gcc generates inefficient code on some architectures
  88  * (powerpc, mips..)
  89  */
  90 static size_t client_packet_header_size(void)
  91 {
  92         return offsetof(struct metadata_packet_header, header_end);
  93 }
  94
  95 static void client_buffer_begin(struct lttng_ust_ring_buffer *buf,
  96                 uint64_t tsc __attribute__((unused)),
  97                 unsigned int subbuf_idx,
  98                 struct lttng_ust_shm_handle *handle)
  99 {
 100         struct lttng_ust_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 101         struct metadata_packet_header *header =
 102                 (struct metadata_packet_header *)
 103                         lib_ring_buffer_offset_address(&buf->backend,
 104                                 subbuf_idx * chan->backend.subbuf_size,
 105                                 handle);
 106         struct lttng_ust_channel_buffer *lttng_chan = channel_get_private(chan);
 107
 108         assert(header);
 109         if (!header)
 110                 return;
 111         header->magic = TSDL_MAGIC_NUMBER;
 112         memcpy(header->uuid, lttng_chan->priv->uuid, sizeof(lttng_chan->priv->uuid));
 113         header->checksum = 0;           /* 0 if unused */
 114         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 115         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 116         header->compression_scheme = 0; /* 0 if unused */
 117         header->encryption_scheme = 0;  /* 0 if unused */
 118         header->checksum_scheme = 0;    /* 0 if unused */
 119         header->major = CTF_SPEC_MAJOR;
 120         header->minor = CTF_SPEC_MINOR;
 121 }
 122
 123 /*
 124  * offset is assumed to never be 0 here : never deliver a completely empty
 125  * subbuffer. data_size is between 1 and subbuf_size.
 126  */
 127 static void client_buffer_end(struct lttng_ust_ring_buffer *buf,
 128                 uint64_t tsc  __attribute__((unused)),
 129                 unsigned int subbuf_idx, unsigned long data_size,
 130                 struct lttng_ust_shm_handle *handle)
 131 {
 132         struct lttng_ust_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 133         struct metadata_packet_header *header =
 134                 (struct metadata_packet_header *)
 135                         lib_ring_buffer_offset_address(&buf->backend,
 136                                 subbuf_idx * chan->backend.subbuf_size,
 137                                 handle);
 138         unsigned long records_lost = 0;
 139
 140         assert(header);
 141         if (!header)
 142                 return;
 143         header->content_size = data_size * CHAR_BIT;            /* in bits */
 144         header->packet_size = LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 145         /*
 146          * We do not care about the records lost count, because the metadata
 147          * channel waits and retry.
 148          */
 149         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 150         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 151         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 152         WARN_ON_ONCE(records_lost != 0);
 153 }
 154
 155 static int client_buffer_create(
 156                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 157                 void *priv __attribute__((unused)),
 158                 int cpu __attribute__((unused)),
 159                 const char *name __attribute__((unused)),
 160                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 161 {
 162         return 0;
 163 }
 164
 165 static void client_buffer_finalize(
 166                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 167                 void *priv __attribute__((unused)),
 168                 int cpu __attribute__((unused)),
 169                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 170 {
 171 }
 172
 173 static const
 174 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 175         .parent = {
 176                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 177                 .record_header_size = client_record_header_size,
 178                 .subbuffer_header_size = client_packet_header_size,
 179                 .buffer_begin = client_buffer_begin,
 180                 .buffer_end = client_buffer_end,
 181                 .buffer_create = client_buffer_create,
 182                 .buffer_finalize = client_buffer_finalize,
 183         },
 184 };
 185
 186 static const struct lttng_ust_ring_buffer_config client_config = {
 187         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 188         .cb.record_header_size = client_record_header_size,
 189         .cb.subbuffer_header_size = client_packet_header_size,
 190         .cb.buffer_begin = client_buffer_begin,
 191         .cb.buffer_end = client_buffer_end,
 192         .cb.buffer_create = client_buffer_create,
 193         .cb.buffer_finalize = client_buffer_finalize,
 194
 195         .tsc_bits = 0,
 196         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 197         .sync = RING_BUFFER_SYNC_GLOBAL,
 198         .mode = RING_BUFFER_MODE_TEMPLATE,
 199         .backend = RING_BUFFER_PAGE,
 200         .output = RING_BUFFER_MMAP,
 201         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 202         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 203         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 204         .client_type = LTTNG_CLIENT_TYPE,
 205
 206          .cb_ptr = &client_cb.parent,
 207 };
 208
 209 static
 210 struct lttng_ust_channel_buffer *_channel_create(const char *name,
 211                                 void *buf_addr,
 212                                 size_t subbuf_size, size_t num_subbuf,
 213                                 unsigned int switch_timer_interval,
 214                                 unsigned int read_timer_interval,
 215                                 unsigned char *uuid,
 216                                 uint32_t chan_id,
 217                                 const int *stream_fds, int nr_stream_fds,
 218                                 int64_t blocking_timeout)
 219 {
 220         struct lttng_ust_abi_channel_config chan_priv_init;
 221         struct lttng_ust_shm_handle *handle;
 222         struct lttng_ust_channel_buffer *lttng_chan_buf;
 223
 224         lttng_chan_buf = lttng_ust_alloc_channel_buffer();
 225         if (!lttng_chan_buf)
 226                 return NULL;
 227         memcpy(lttng_chan_buf->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
 228         lttng_chan_buf->priv->id = chan_id;
 229
 230         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 231         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 232         chan_priv_init.id = chan_id;
 233
 234         handle = channel_create(&client_config, name,
 235                         __alignof__(struct lttng_ust_channel_buffer),
 236                         sizeof(struct lttng_ust_channel_buffer),
 237                         &chan_priv_init,
 238                         lttng_chan_buf, buf_addr, subbuf_size, num_subbuf,
 239                         switch_timer_interval, read_timer_interval,
 240                         stream_fds, nr_stream_fds, blocking_timeout);
 241         if (!handle)
 242                 goto error;
 243         lttng_chan_buf->priv->rb_chan = shmp(handle, handle->chan);
 244         return lttng_chan_buf;
 245
 246 error:
 247         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 248         return NULL;
 249 }
 250
 251 static
 252 void lttng_channel_destroy(struct lttng_ust_channel_buffer *lttng_chan_buf)
 253 {
 254         channel_destroy(lttng_chan_buf->priv->rb_chan, lttng_chan_buf->priv->rb_chan->handle, 1);
 255         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 256 }
 257
 258 static
 259 int lttng_event_reserve(struct lttng_ust_ring_buffer_ctx *ctx)
 260 {
 261         int ret;
 262
 263         memset(&URCU_TLS(private_ctx), 0, sizeof(struct lttng_ust_ring_buffer_ctx_private));
 264         URCU_TLS(private_ctx).pub = ctx;
 265         URCU_TLS(private_ctx).chan = ctx->client_priv;
 266         ctx->priv = &URCU_TLS(private_ctx);
 267         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 268         if (ret)
 269                 return ret;
 270         if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 271                         &ctx->priv->backend_pages))
 272                 return -EPERM;
 273         return 0;
 274 }
 275
 276 static
 277 void lttng_event_commit(struct lttng_ust_ring_buffer_ctx *ctx)
 278 {
 279         lib_ring_buffer_commit(&client_config, ctx);
 280 }
 281
 282 static
 283 void lttng_event_write(struct lttng_ust_ring_buffer_ctx *ctx,
 284                 const void *src, size_t len, size_t alignment)
 285 {
 286         lttng_ust_ring_buffer_align_ctx(ctx, alignment);
 287         lib_ring_buffer_write(&client_config, ctx, src, len);
 288 }
 289
 290 static
 291 size_t lttng_packet_avail_size(struct lttng_ust_channel_buffer *chan)
 292 {
 293         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 294         unsigned long o_begin;
 295         struct lttng_ust_ring_buffer *buf;
 296
 297         buf = shmp(rb_chan->handle, rb_chan->backend.buf[0].shmp);      /* Only for global buffer ! */
 298         o_begin = v_read(&client_config, &buf->offset);
 299         if (subbuf_offset(o_begin, rb_chan) != 0) {
 300                 return rb_chan->backend.subbuf_size - subbuf_offset(o_begin, rb_chan);
 301         } else {
 302                 return rb_chan->backend.subbuf_size - subbuf_offset(o_begin, rb_chan)
 303                         - sizeof(struct metadata_packet_header);
 304         }
 305 }
 306
 307 static
 308 int lttng_is_finalized(struct lttng_ust_channel_buffer *chan)
 309 {
 310         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 311
 312         return lib_ring_buffer_channel_is_finalized(rb_chan);
 313 }
 314
 315 static
 316 int lttng_is_disabled(struct lttng_ust_channel_buffer *chan)
 317 {
 318         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 319
 320         return lib_ring_buffer_channel_is_disabled(rb_chan);
 321 }
 322
 323 static
 324 int lttng_flush_buffer(struct lttng_ust_channel_buffer *chan)
 325 {
 326         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 327         struct lttng_ust_ring_buffer *buf;
 328         int shm_fd, wait_fd, wakeup_fd;
 329         uint64_t memory_map_size;
 330
 331         buf = channel_get_ring_buffer(&client_config, rb_chan,
 332                         0, rb_chan->handle, &shm_fd, &wait_fd, &wakeup_fd,
 333                         &memory_map_size);
 334         lib_ring_buffer_switch(&client_config, buf,
 335                         SWITCH_ACTIVE, rb_chan->handle);
 336         return 0;
 337 }
 338
 339 static struct lttng_transport lttng_relay_transport = {
 340         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 341         .ops = {
 342                 .struct_size = sizeof(struct lttng_ust_channel_buffer_ops),
 343
 344                 .priv = LTTNG_UST_COMPOUND_LITERAL(struct lttng_ust_channel_buffer_ops_private, {
 345                         .pub = &lttng_relay_transport.ops,
 346                         .channel_create = _channel_create,
 347                         .channel_destroy = lttng_channel_destroy,
 348                         .packet_avail_size = lttng_packet_avail_size,
 349                         .is_finalized = lttng_is_finalized,
 350                         .is_disabled = lttng_is_disabled,
 351                         .flush_buffer = lttng_flush_buffer,
 352                 }),
 353                 .event_reserve = lttng_event_reserve,
 354                 .event_commit = lttng_event_commit,
 355                 .event_write = lttng_event_write,
 356         },
 357         .client_config = &client_config,
 358 };
 359
 360 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 361 {
 362         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 363                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 364         lttng_transport_register(&lttng_relay_transport);
 365 }
 366
 367 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 368 {
 369         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 370                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 371         lttng_transport_unregister(&lttng_relay_transport);
 372 }