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