liblttng-ust/lttng-ring-buffer-metadata-client.h

   1 /*
   2  * lttng-ring-buffer-client.h
   3  *
   4  * LTTng lib ring buffer client template.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <stdint.h>
  24 #include <lttng/ust-events.h>
  25 #include "lttng/bitfield.h"
  26 #include "lttng-tracer.h"
  27 #include "../libringbuffer/frontend_types.h"
  28
  29 struct metadata_packet_header {
  30         uint32_t magic;                 /* 0x75D11D57 */
  31         uint8_t  uuid[LTTNG_UST_UUID_LEN]; /* Unique Universal Identifier */
  32         uint32_t checksum;              /* 0 if unused */
  33         uint32_t content_size;          /* in bits */
  34         uint32_t packet_size;           /* in bits */
  35         uint8_t  compression_scheme;    /* 0 if unused */
  36         uint8_t  encryption_scheme;     /* 0 if unused */
  37         uint8_t  checksum_scheme;       /* 0 if unused */
  38         uint8_t  major;                 /* CTF spec major version number */
  39         uint8_t  minor;                 /* CTF spec minor version number */
  40         uint8_t  header_end[0];
  41 };
  42
  43 struct metadata_record_header {
  44         uint8_t header_end[0];          /* End of header */
  45 };
  46
  47 static const struct lttng_ust_lib_ring_buffer_config client_config;
  48
  49 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  50 {
  51         return 0;
  52 }
  53
  54 static inline
  55 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  56                                  struct channel *chan, size_t offset,
  57                                  size_t *pre_header_padding,
  58                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
  59 {
  60         return 0;
  61 }
  62
  63 #include "../libringbuffer/api.h"
  64 #include "lttng-rb-clients.h"
  65
  66 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
  67 {
  68         return 0;
  69 }
  70
  71 static
  72 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  73                                  struct channel *chan, size_t offset,
  74                                  size_t *pre_header_padding,
  75                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
  76 {
  77         return 0;
  78 }
  79
  80 /**
  81  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  82  *
  83  * Return header size without padding after the structure. Don't use packed
  84  * structure because gcc generates inefficient code on some architectures
  85  * (powerpc, mips..)
  86  */
  87 static size_t client_packet_header_size(void)
  88 {
  89         return offsetof(struct metadata_packet_header, header_end);
  90 }
  91
  92 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
  93                                 unsigned int subbuf_idx,
  94                                 struct lttng_ust_shm_handle *handle)
  95 {
  96         struct channel *chan = shmp(handle, buf->backend.chan);
  97         struct metadata_packet_header *header =
  98                 (struct metadata_packet_header *)
  99                         lib_ring_buffer_offset_address(&buf->backend,
 100                                 subbuf_idx * chan->backend.subbuf_size,
 101                                 handle);
 102         struct lttng_channel *lttng_chan = channel_get_private(chan);
 103
 104         assert(header);
 105         if (!header)
 106                 return;
 107         header->magic = TSDL_MAGIC_NUMBER;
 108         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 109         header->checksum = 0;           /* 0 if unused */
 110         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 111         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 112         header->compression_scheme = 0; /* 0 if unused */
 113         header->encryption_scheme = 0;  /* 0 if unused */
 114         header->checksum_scheme = 0;    /* 0 if unused */
 115         header->major = CTF_SPEC_MAJOR;
 116         header->minor = CTF_SPEC_MINOR;
 117 }
 118
 119 /*
 120  * offset is assumed to never be 0 here : never deliver a completely empty
 121  * subbuffer. data_size is between 1 and subbuf_size.
 122  */
 123 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 124                               unsigned int subbuf_idx, unsigned long data_size,
 125                               struct lttng_ust_shm_handle *handle)
 126 {
 127         struct channel *chan = shmp(handle, buf->backend.chan);
 128         struct metadata_packet_header *header =
 129                 (struct metadata_packet_header *)
 130                         lib_ring_buffer_offset_address(&buf->backend,
 131                                 subbuf_idx * chan->backend.subbuf_size,
 132                                 handle);
 133         unsigned long records_lost = 0;
 134
 135         assert(header);
 136         if (!header)
 137                 return;
 138         header->content_size = data_size * CHAR_BIT;            /* in bits */
 139         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 140         /*
 141          * We do not care about the records lost count, because the metadata
 142          * channel waits and retry.
 143          */
 144         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 145         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 146         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 147         WARN_ON_ONCE(records_lost != 0);
 148 }
 149
 150 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 151                                 int cpu, const char *name,
 152                                 struct lttng_ust_shm_handle *handle)
 153 {
 154         return 0;
 155 }
 156
 157 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 158                                    void *priv, int cpu,
 159                                    struct lttng_ust_shm_handle *handle)
 160 {
 161 }
 162
 163 static const
 164 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 165         .parent = {
 166                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 167                 .record_header_size = client_record_header_size,
 168                 .subbuffer_header_size = client_packet_header_size,
 169                 .buffer_begin = client_buffer_begin,
 170                 .buffer_end = client_buffer_end,
 171                 .buffer_create = client_buffer_create,
 172                 .buffer_finalize = client_buffer_finalize,
 173         },
 174 };
 175
 176 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 177         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 178         .cb.record_header_size = client_record_header_size,
 179         .cb.subbuffer_header_size = client_packet_header_size,
 180         .cb.buffer_begin = client_buffer_begin,
 181         .cb.buffer_end = client_buffer_end,
 182         .cb.buffer_create = client_buffer_create,
 183         .cb.buffer_finalize = client_buffer_finalize,
 184
 185         .tsc_bits = 0,
 186         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 187         .sync = RING_BUFFER_SYNC_GLOBAL,
 188         .mode = RING_BUFFER_MODE_TEMPLATE,
 189         .backend = RING_BUFFER_PAGE,
 190         .output = RING_BUFFER_MMAP,
 191         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 192         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 193         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 194         .client_type = LTTNG_CLIENT_TYPE,
 195
 196          .cb_ptr = &client_cb.parent,
 197 };
 198
 199 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 200
 201 static
 202 struct lttng_channel *_channel_create(const char *name,
 203                                 void *buf_addr,
 204                                 size_t subbuf_size, size_t num_subbuf,
 205                                 unsigned int switch_timer_interval,
 206                                 unsigned int read_timer_interval,
 207                                 unsigned char *uuid,
 208                                 uint32_t chan_id,
 209                                 const int *stream_fds, int nr_stream_fds,
 210                                 int64_t blocking_timeout)
 211 {
 212         struct lttng_channel chan_priv_init;
 213         struct lttng_ust_shm_handle *handle;
 214         struct lttng_channel *lttng_chan;
 215         void *priv;
 216
 217         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 218         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 219         chan_priv_init.id = chan_id;
 220         handle = channel_create(&client_config, name,
 221                         &priv, __alignof__(struct lttng_channel),
 222                         sizeof(struct lttng_channel),
 223                         &chan_priv_init,
 224                         buf_addr, subbuf_size, num_subbuf,
 225                         switch_timer_interval, read_timer_interval,
 226                         stream_fds, nr_stream_fds, blocking_timeout);
 227         if (!handle)
 228                 return NULL;
 229         lttng_chan = priv;
 230         lttng_chan->handle = handle;
 231         lttng_chan->chan = shmp(handle, handle->chan);
 232         return lttng_chan;
 233 }
 234
 235 static
 236 void lttng_channel_destroy(struct lttng_channel *chan)
 237 {
 238         channel_destroy(chan->chan, chan->handle, 1);
 239 }
 240
 241 static
 242 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 243 {
 244         int ret;
 245
 246         ret = lib_ring_buffer_reserve(&client_config, ctx);
 247         if (ret)
 248                 return ret;
 249         if (caa_likely(ctx->ctx_len
 250                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 251                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 252                                 &ctx->backend_pages))
 253                         return -EPERM;
 254         }
 255         return 0;
 256 }
 257
 258 static
 259 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 260 {
 261         lib_ring_buffer_commit(&client_config, ctx);
 262 }
 263
 264 static
 265 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 266                      size_t len)
 267 {
 268         lib_ring_buffer_write(&client_config, ctx, src, len);
 269 }
 270
 271 static
 272 size_t lttng_packet_avail_size(struct channel *chan, struct lttng_ust_shm_handle *handle)
 273
 274 {
 275         unsigned long o_begin;
 276         struct lttng_ust_lib_ring_buffer *buf;
 277
 278         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 279         o_begin = v_read(&client_config, &buf->offset);
 280         if (subbuf_offset(o_begin, chan) != 0) {
 281                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 282         } else {
 283                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 284                         - sizeof(struct metadata_packet_header);
 285         }
 286 }
 287
 288 #if 0
 289 static
 290 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 291 {
 292         return &chan->read_wait;
 293 }
 294
 295 static
 296 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 297 {
 298         return &chan->hp_wait;
 299 }
 300 #endif //0
 301
 302 static
 303 int lttng_is_finalized(struct channel *chan)
 304 {
 305         return lib_ring_buffer_channel_is_finalized(chan);
 306 }
 307
 308 static
 309 int lttng_is_disabled(struct channel *chan)
 310 {
 311         return lib_ring_buffer_channel_is_disabled(chan);
 312 }
 313
 314 static
 315 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 316 {
 317         struct lttng_ust_lib_ring_buffer *buf;
 318         int shm_fd, wait_fd, wakeup_fd;
 319         uint64_t memory_map_size;
 320
 321         buf = channel_get_ring_buffer(&client_config, chan,
 322                         0, handle, &shm_fd, &wait_fd, &wakeup_fd,
 323                         &memory_map_size);
 324         lib_ring_buffer_switch(&client_config, buf,
 325                         SWITCH_ACTIVE, handle);
 326         return 0;
 327 }
 328
 329 static struct lttng_transport lttng_relay_transport = {
 330         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 331         .ops = {
 332                 .channel_create = _channel_create,
 333                 .channel_destroy = lttng_channel_destroy,
 334                 .event_reserve = lttng_event_reserve,
 335                 .event_commit = lttng_event_commit,
 336                 .event_write = lttng_event_write,
 337                 .packet_avail_size = lttng_packet_avail_size,
 338                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 339                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 340                 .is_finalized = lttng_is_finalized,
 341                 .is_disabled = lttng_is_disabled,
 342                 .flush_buffer = lttng_flush_buffer,
 343         },
 344         .client_config = &client_config,
 345 };
 346
 347 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 348 {
 349         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 350                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 351         lttng_transport_register(&lttng_relay_transport);
 352 }
 353
 354 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 355 {
 356         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 357                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 358         lttng_transport_unregister(&lttng_relay_transport);
 359 }