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                 const struct lttng_ust_ring_buffer_ctx *ctx)
 132 {
 133         struct lttng_ust_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 134         struct metadata_packet_header *header =
 135                 (struct metadata_packet_header *)
 136                         lib_ring_buffer_offset_address(&buf->backend,
 137                                 subbuf_idx * chan->backend.subbuf_size,
 138                                 handle);
 139         unsigned long records_lost = 0;
 140
 141         assert(header);
 142         if (!header)
 143                 return;
 144         header->content_size = data_size * CHAR_BIT;            /* in bits */
 145         header->packet_size = LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 146         /*
 147          * We do not care about the records lost count, because the metadata
 148          * channel waits and retry.
 149          */
 150         (void) lib_ring_buffer_get_records_lost_full(&client_config, ctx);
 151         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, ctx);
 152         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, ctx);
 153         WARN_ON_ONCE(records_lost != 0);
 154 }
 155
 156 static int client_buffer_create(
 157                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 158                 void *priv __attribute__((unused)),
 159                 int cpu __attribute__((unused)),
 160                 const char *name __attribute__((unused)),
 161                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 162 {
 163         return 0;
 164 }
 165
 166 static void client_buffer_finalize(
 167                 struct lttng_ust_ring_buffer *buf __attribute__((unused)),
 168                 void *priv __attribute__((unused)),
 169                 int cpu __attribute__((unused)),
 170                 struct lttng_ust_shm_handle *handle __attribute__((unused)))
 171 {
 172 }
 173
 174 static const
 175 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 176         .parent = {
 177                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 178                 .record_header_size = client_record_header_size,
 179                 .subbuffer_header_size = client_packet_header_size,
 180                 .buffer_begin = client_buffer_begin,
 181                 .buffer_end = client_buffer_end,
 182                 .buffer_create = client_buffer_create,
 183                 .buffer_finalize = client_buffer_finalize,
 184         },
 185 };
 186
 187 static const struct lttng_ust_ring_buffer_config client_config = {
 188         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 189         .cb.record_header_size = client_record_header_size,
 190         .cb.subbuffer_header_size = client_packet_header_size,
 191         .cb.buffer_begin = client_buffer_begin,
 192         .cb.buffer_end = client_buffer_end,
 193         .cb.buffer_create = client_buffer_create,
 194         .cb.buffer_finalize = client_buffer_finalize,
 195
 196         .tsc_bits = 0,
 197         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 198         .sync = RING_BUFFER_SYNC_GLOBAL,
 199         .mode = RING_BUFFER_MODE_TEMPLATE,
 200         .backend = RING_BUFFER_PAGE,
 201         .output = RING_BUFFER_MMAP,
 202         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 203         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 204         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 205         .client_type = LTTNG_CLIENT_TYPE,
 206
 207          .cb_ptr = &client_cb.parent,
 208 };
 209
 210 static
 211 struct lttng_ust_channel_buffer *_channel_create(const char *name,
 212                                 void *buf_addr,
 213                                 size_t subbuf_size, size_t num_subbuf,
 214                                 unsigned int switch_timer_interval,
 215                                 unsigned int read_timer_interval,
 216                                 unsigned char *uuid,
 217                                 uint32_t chan_id,
 218                                 const int *stream_fds, int nr_stream_fds,
 219                                 int64_t blocking_timeout)
 220 {
 221         struct lttng_ust_abi_channel_config chan_priv_init;
 222         struct lttng_ust_shm_handle *handle;
 223         struct lttng_ust_channel_buffer *lttng_chan_buf;
 224
 225         lttng_chan_buf = lttng_ust_alloc_channel_buffer();
 226         if (!lttng_chan_buf)
 227                 return NULL;
 228         memcpy(lttng_chan_buf->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
 229         lttng_chan_buf->priv->id = chan_id;
 230
 231         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 232         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 233         chan_priv_init.id = chan_id;
 234
 235         handle = channel_create(&client_config, name,
 236                         __alignof__(struct lttng_ust_channel_buffer),
 237                         sizeof(struct lttng_ust_channel_buffer),
 238                         &chan_priv_init,
 239                         lttng_chan_buf, buf_addr, subbuf_size, num_subbuf,
 240                         switch_timer_interval, read_timer_interval,
 241                         stream_fds, nr_stream_fds, blocking_timeout);
 242         if (!handle)
 243                 goto error;
 244         lttng_chan_buf->priv->rb_chan = shmp(handle, handle->chan);
 245         return lttng_chan_buf;
 246
 247 error:
 248         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 249         return NULL;
 250 }
 251
 252 static
 253 void lttng_channel_destroy(struct lttng_ust_channel_buffer *lttng_chan_buf)
 254 {
 255         channel_destroy(lttng_chan_buf->priv->rb_chan, lttng_chan_buf->priv->rb_chan->handle, 1);
 256         lttng_ust_free_channel_common(lttng_chan_buf->parent);
 257 }
 258
 259 static
 260 int lttng_event_reserve(struct lttng_ust_ring_buffer_ctx *ctx)
 261 {
 262         int ret;
 263
 264         memset(&URCU_TLS(private_ctx), 0, sizeof(struct lttng_ust_ring_buffer_ctx_private));
 265         URCU_TLS(private_ctx).pub = ctx;
 266         URCU_TLS(private_ctx).chan = ctx->client_priv;
 267         ctx->priv = &URCU_TLS(private_ctx);
 268         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 269         if (ret)
 270                 return ret;
 271         if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 272                         &ctx->priv->backend_pages))
 273                 return -EPERM;
 274         return 0;
 275 }
 276
 277 static
 278 void lttng_event_commit(struct lttng_ust_ring_buffer_ctx *ctx)
 279 {
 280         lib_ring_buffer_commit(&client_config, ctx);
 281 }
 282
 283 static
 284 void lttng_event_write(struct lttng_ust_ring_buffer_ctx *ctx,
 285                 const void *src, size_t len, size_t alignment)
 286 {
 287         lttng_ust_ring_buffer_align_ctx(ctx, alignment);
 288         lib_ring_buffer_write(&client_config, ctx, src, len);
 289 }
 290
 291 static
 292 size_t lttng_packet_avail_size(struct lttng_ust_channel_buffer *chan)
 293 {
 294         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 295         unsigned long o_begin;
 296         struct lttng_ust_ring_buffer *buf;
 297
 298         buf = shmp(rb_chan->handle, rb_chan->backend.buf[0].shmp);      /* Only for global buffer ! */
 299         o_begin = v_read(&client_config, &buf->offset);
 300         if (subbuf_offset(o_begin, rb_chan) != 0) {
 301                 return rb_chan->backend.subbuf_size - subbuf_offset(o_begin, rb_chan);
 302         } else {
 303                 return rb_chan->backend.subbuf_size - subbuf_offset(o_begin, rb_chan)
 304                         - sizeof(struct metadata_packet_header);
 305         }
 306 }
 307
 308 static
 309 int lttng_is_finalized(struct lttng_ust_channel_buffer *chan)
 310 {
 311         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 312
 313         return lib_ring_buffer_channel_is_finalized(rb_chan);
 314 }
 315
 316 static
 317 int lttng_is_disabled(struct lttng_ust_channel_buffer *chan)
 318 {
 319         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 320
 321         return lib_ring_buffer_channel_is_disabled(rb_chan);
 322 }
 323
 324 static
 325 int lttng_flush_buffer(struct lttng_ust_channel_buffer *chan)
 326 {
 327         struct lttng_ust_ring_buffer_channel *rb_chan = chan->priv->rb_chan;
 328         struct lttng_ust_ring_buffer *buf;
 329         int shm_fd, wait_fd, wakeup_fd;
 330         uint64_t memory_map_size;
 331         void *memory_map_addr;
 332
 333         buf = channel_get_ring_buffer(&client_config, rb_chan,
 334                         0, rb_chan->handle, &shm_fd, &wait_fd, &wakeup_fd,
 335                         &memory_map_size, &memory_map_addr);
 336         lib_ring_buffer_switch(&client_config, buf,
 337                         SWITCH_ACTIVE, rb_chan->handle);
 338         return 0;
 339 }
 340
 341 static struct lttng_transport lttng_relay_transport = {
 342         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 343         .ops = {
 344                 .struct_size = sizeof(struct lttng_ust_channel_buffer_ops),
 345
 346                 .priv = LTTNG_UST_COMPOUND_LITERAL(struct lttng_ust_channel_buffer_ops_private, {
 347                         .pub = &lttng_relay_transport.ops,
 348                         .channel_create = _channel_create,
 349                         .channel_destroy = lttng_channel_destroy,
 350                         .packet_avail_size = lttng_packet_avail_size,
 351                         .is_finalized = lttng_is_finalized,
 352                         .is_disabled = lttng_is_disabled,
 353                         .flush_buffer = lttng_flush_buffer,
 354                 }),
 355                 .event_reserve = lttng_event_reserve,
 356                 .event_commit = lttng_event_commit,
 357                 .event_write = lttng_event_write,
 358         },
 359         .client_config = &client_config,
 360 };
 361
 362 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 363 {
 364         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 365                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 366         lttng_transport_register(&lttng_relay_transport);
 367 }
 368
 369 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 370 {
 371         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 372                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 373         lttng_transport_unregister(&lttng_relay_transport);
 374 }