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 <stddef.h>
  24 #include <stdint.h>
  25 #include <lttng/ust-events.h>
  26 #include "lttng/bitfield.h"
  27 #include "lttng-tracer.h"
  28 #include "../libringbuffer/frontend_types.h"
  29
  30 struct metadata_packet_header {
  31         uint32_t magic;                 /* 0x75D11D57 */
  32         uint8_t  uuid[LTTNG_UST_UUID_LEN]; /* Unique Universal Identifier */
  33         uint32_t checksum;              /* 0 if unused */
  34         uint32_t content_size;          /* in bits */
  35         uint32_t packet_size;           /* in bits */
  36         uint8_t  compression_scheme;    /* 0 if unused */
  37         uint8_t  encryption_scheme;     /* 0 if unused */
  38         uint8_t  checksum_scheme;       /* 0 if unused */
  39         uint8_t  major;                 /* CTF spec major version number */
  40         uint8_t  minor;                 /* CTF spec minor version number */
  41         uint8_t  header_end[0];
  42 };
  43
  44 struct metadata_record_header {
  45         uint8_t header_end[0];          /* End of header */
  46 };
  47
  48 static const struct lttng_ust_lib_ring_buffer_config client_config;
  49
  50 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  51 {
  52         return 0;
  53 }
  54
  55 static inline
  56 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  57                                  struct channel *chan, size_t offset,
  58                                  size_t *pre_header_padding,
  59                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  60                                  void *client_ctx)
  61 {
  62         return 0;
  63 }
  64
  65 #include "../libringbuffer/api.h"
  66 #include "lttng-rb-clients.h"
  67
  68 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
  69 {
  70         return 0;
  71 }
  72
  73 static
  74 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  75                                  struct channel *chan, size_t offset,
  76                                  size_t *pre_header_padding,
  77                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  78                                  void *client_ctx)
  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_lib_ring_buffer *buf, uint64_t tsc,
  96                                 unsigned int subbuf_idx,
  97                                 struct lttng_ust_shm_handle *handle)
  98 {
  99         struct channel *chan = shmp(handle, buf->backend.chan);
 100         struct metadata_packet_header *header =
 101                 (struct metadata_packet_header *)
 102                         lib_ring_buffer_offset_address(&buf->backend,
 103                                 subbuf_idx * chan->backend.subbuf_size,
 104                                 handle);
 105         struct lttng_channel *lttng_chan = channel_get_private(chan);
 106
 107         assert(header);
 108         if (!header)
 109                 return;
 110         header->magic = TSDL_MAGIC_NUMBER;
 111         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 112         header->checksum = 0;           /* 0 if unused */
 113         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 114         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 115         header->compression_scheme = 0; /* 0 if unused */
 116         header->encryption_scheme = 0;  /* 0 if unused */
 117         header->checksum_scheme = 0;    /* 0 if unused */
 118         header->major = CTF_SPEC_MAJOR;
 119         header->minor = CTF_SPEC_MINOR;
 120 }
 121
 122 /*
 123  * offset is assumed to never be 0 here : never deliver a completely empty
 124  * subbuffer. data_size is between 1 and subbuf_size.
 125  */
 126 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 127                               unsigned int subbuf_idx, unsigned long data_size,
 128                               struct lttng_ust_shm_handle *handle)
 129 {
 130         struct channel *chan = shmp(handle, buf->backend.chan);
 131         struct metadata_packet_header *header =
 132                 (struct metadata_packet_header *)
 133                         lib_ring_buffer_offset_address(&buf->backend,
 134                                 subbuf_idx * chan->backend.subbuf_size,
 135                                 handle);
 136         unsigned long records_lost = 0;
 137
 138         assert(header);
 139         if (!header)
 140                 return;
 141         header->content_size = data_size * CHAR_BIT;            /* in bits */
 142         header->packet_size = LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 143         /*
 144          * We do not care about the records lost count, because the metadata
 145          * channel waits and retry.
 146          */
 147         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 148         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 149         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 150         WARN_ON_ONCE(records_lost != 0);
 151 }
 152
 153 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 154                                 int cpu, const char *name,
 155                                 struct lttng_ust_shm_handle *handle)
 156 {
 157         return 0;
 158 }
 159
 160 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 161                                    void *priv, int cpu,
 162                                    struct lttng_ust_shm_handle *handle)
 163 {
 164 }
 165
 166 static const
 167 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 168         .parent = {
 169                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 170                 .record_header_size = client_record_header_size,
 171                 .subbuffer_header_size = client_packet_header_size,
 172                 .buffer_begin = client_buffer_begin,
 173                 .buffer_end = client_buffer_end,
 174                 .buffer_create = client_buffer_create,
 175                 .buffer_finalize = client_buffer_finalize,
 176         },
 177 };
 178
 179 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 180         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 181         .cb.record_header_size = client_record_header_size,
 182         .cb.subbuffer_header_size = client_packet_header_size,
 183         .cb.buffer_begin = client_buffer_begin,
 184         .cb.buffer_end = client_buffer_end,
 185         .cb.buffer_create = client_buffer_create,
 186         .cb.buffer_finalize = client_buffer_finalize,
 187
 188         .tsc_bits = 0,
 189         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 190         .sync = RING_BUFFER_SYNC_GLOBAL,
 191         .mode = RING_BUFFER_MODE_TEMPLATE,
 192         .backend = RING_BUFFER_PAGE,
 193         .output = RING_BUFFER_MMAP,
 194         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 195         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 196         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 197         .client_type = LTTNG_CLIENT_TYPE,
 198
 199          .cb_ptr = &client_cb.parent,
 200 };
 201
 202 const struct lttng_ust_client_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 203
 204 static
 205 struct lttng_channel *_channel_create(const char *name,
 206                                 void *buf_addr,
 207                                 size_t subbuf_size, size_t num_subbuf,
 208                                 unsigned int switch_timer_interval,
 209                                 unsigned int read_timer_interval,
 210                                 unsigned char *uuid,
 211                                 uint32_t chan_id,
 212                                 const int *stream_fds, int nr_stream_fds,
 213                                 int64_t blocking_timeout)
 214 {
 215         struct lttng_channel chan_priv_init;
 216         struct lttng_ust_shm_handle *handle;
 217         struct lttng_channel *lttng_chan;
 218         void *priv;
 219
 220         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 221         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 222         chan_priv_init.id = chan_id;
 223         handle = channel_create(&client_config, name,
 224                         &priv, __alignof__(struct lttng_channel),
 225                         sizeof(struct lttng_channel),
 226                         &chan_priv_init,
 227                         buf_addr, subbuf_size, num_subbuf,
 228                         switch_timer_interval, read_timer_interval,
 229                         stream_fds, nr_stream_fds, blocking_timeout);
 230         if (!handle)
 231                 return NULL;
 232         lttng_chan = priv;
 233         lttng_chan->handle = handle;
 234         lttng_chan->chan = shmp(handle, handle->chan);
 235         return lttng_chan;
 236 }
 237
 238 static
 239 void lttng_channel_destroy(struct lttng_channel *chan)
 240 {
 241         channel_destroy(chan->chan, chan->handle, 1);
 242 }
 243
 244 static
 245 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 246 {
 247         int ret;
 248
 249         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 250         if (ret)
 251                 return ret;
 252         if (caa_likely(ctx->ctx_len
 253                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 254                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 255                                 &ctx->backend_pages))
 256                         return -EPERM;
 257         }
 258         return 0;
 259 }
 260
 261 static
 262 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 263 {
 264         lib_ring_buffer_commit(&client_config, ctx);
 265 }
 266
 267 static
 268 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 269                      size_t len)
 270 {
 271         lib_ring_buffer_write(&client_config, ctx, src, len);
 272 }
 273
 274 static
 275 size_t lttng_packet_avail_size(struct channel *chan, struct lttng_ust_shm_handle *handle)
 276 {
 277         unsigned long o_begin;
 278         struct lttng_ust_lib_ring_buffer *buf;
 279
 280         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 281         o_begin = v_read(&client_config, &buf->offset);
 282         if (subbuf_offset(o_begin, chan) != 0) {
 283                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 284         } else {
 285                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 286                         - sizeof(struct metadata_packet_header);
 287         }
 288 }
 289
 290 #if 0
 291 static
 292 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 293 {
 294         return &chan->read_wait;
 295 }
 296
 297 static
 298 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 299 {
 300         return &chan->hp_wait;
 301 }
 302 #endif //0
 303
 304 static
 305 int lttng_is_finalized(struct channel *chan)
 306 {
 307         return lib_ring_buffer_channel_is_finalized(chan);
 308 }
 309
 310 static
 311 int lttng_is_disabled(struct channel *chan)
 312 {
 313         return lib_ring_buffer_channel_is_disabled(chan);
 314 }
 315
 316 static
 317 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 318 {
 319         struct lttng_ust_lib_ring_buffer *buf;
 320         int shm_fd, wait_fd, wakeup_fd;
 321         uint64_t memory_map_size;
 322
 323         buf = channel_get_ring_buffer(&client_config, chan,
 324                         0, handle, &shm_fd, &wait_fd, &wakeup_fd,
 325                         &memory_map_size);
 326         lib_ring_buffer_switch(&client_config, buf,
 327                         SWITCH_ACTIVE, handle);
 328         return 0;
 329 }
 330
 331 static struct lttng_transport lttng_relay_transport = {
 332         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 333         .ops = {
 334                 .channel_create = _channel_create,
 335                 .channel_destroy = lttng_channel_destroy,
 336                 .event_reserve = lttng_event_reserve,
 337                 .event_commit = lttng_event_commit,
 338                 .event_write = lttng_event_write,
 339                 .packet_avail_size = lttng_packet_avail_size,
 340                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 341                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 342                 .is_finalized = lttng_is_finalized,
 343                 .is_disabled = lttng_is_disabled,
 344                 .flush_buffer = lttng_flush_buffer,
 345         },
 346         .client_config = &client_config,
 347 };
 348
 349 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 350 {
 351         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 352                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 353         lttng_transport_register(&lttng_relay_transport);
 354 }
 355
 356 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 357 {
 358         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 359                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 360         lttng_transport_unregister(&lttng_relay_transport);
 361 }