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