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

   1 /*
   2  * ltt-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 "ltt-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 unsigned char 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
  65 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
  66 {
  67         return 0;
  68 }
  69
  70 static
  71 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  72                                  struct channel *chan, size_t offset,
  73                                  size_t *pre_header_padding,
  74                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
  75 {
  76         return 0;
  77 }
  78
  79 /**
  80  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  81  *
  82  * Return header size without padding after the structure. Don't use packed
  83  * structure because gcc generates inefficient code on some architectures
  84  * (powerpc, mips..)
  85  */
  86 static size_t client_packet_header_size(void)
  87 {
  88         return offsetof(struct metadata_packet_header, header_end);
  89 }
  90
  91 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
  92                                 unsigned int subbuf_idx,
  93                                 struct lttng_ust_shm_handle *handle)
  94 {
  95         struct channel *chan = shmp(handle, buf->backend.chan);
  96         struct metadata_packet_header *header =
  97                 (struct metadata_packet_header *)
  98                         lib_ring_buffer_offset_address(&buf->backend,
  99                                 subbuf_idx * chan->backend.subbuf_size,
 100                                 handle);
 101         struct ltt_channel *ltt_chan = channel_get_private(chan);
 102
 103         header->magic = TSDL_MAGIC_NUMBER;
 104         memcpy(header->uuid, ltt_chan->uuid, sizeof(ltt_chan->uuid));
 105         header->checksum = 0;           /* 0 if unused */
 106         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 107         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 108         header->compression_scheme = 0; /* 0 if unused */
 109         header->encryption_scheme = 0;  /* 0 if unused */
 110         header->checksum_scheme = 0;    /* 0 if unused */
 111         header->major = CTF_SPEC_MAJOR;
 112         header->minor = CTF_SPEC_MINOR;
 113
 114 }
 115
 116 /*
 117  * offset is assumed to never be 0 here : never deliver a completely empty
 118  * subbuffer. data_size is between 1 and subbuf_size.
 119  */
 120 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 121                               unsigned int subbuf_idx, unsigned long data_size,
 122                               struct lttng_ust_shm_handle *handle)
 123 {
 124         struct channel *chan = shmp(handle, buf->backend.chan);
 125         struct metadata_packet_header *header =
 126                 (struct metadata_packet_header *)
 127                         lib_ring_buffer_offset_address(&buf->backend,
 128                                 subbuf_idx * chan->backend.subbuf_size,
 129                                 handle);
 130         unsigned long records_lost = 0;
 131
 132         header->content_size = data_size * CHAR_BIT;            /* in bits */
 133         header->packet_size = 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 struct lttng_ust_lib_ring_buffer_config client_config = {
 158         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 159         .cb.record_header_size = client_record_header_size,
 160         .cb.subbuffer_header_size = client_packet_header_size,
 161         .cb.buffer_begin = client_buffer_begin,
 162         .cb.buffer_end = client_buffer_end,
 163         .cb.buffer_create = client_buffer_create,
 164         .cb.buffer_finalize = client_buffer_finalize,
 165
 166         .tsc_bits = 0,
 167         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 168         .sync = RING_BUFFER_SYNC_GLOBAL,
 169         .mode = RING_BUFFER_MODE_TEMPLATE,
 170         .backend = RING_BUFFER_PAGE,
 171         .output = RING_BUFFER_MMAP,
 172         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 173         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 174         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 175         .client_type = LTTNG_CLIENT_TYPE,
 176 };
 177
 178 const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
 179
 180 static
 181 struct ltt_channel *_channel_create(const char *name,
 182                                 void *buf_addr,
 183                                 size_t subbuf_size, size_t num_subbuf,
 184                                 unsigned int switch_timer_interval,
 185                                 unsigned int read_timer_interval,
 186                                 int **shm_fd, char **shm_path,
 187                                 int **wait_fd, char **wait_pipe_path,
 188                                 uint64_t **memory_map_size,
 189                                 struct ltt_channel *chan_priv_init)
 190 {
 191         void *priv;
 192         struct ltt_channel *ltt_chan = NULL;
 193         struct lttng_ust_shm_handle *handle;
 194
 195         handle = channel_create(&client_config, name,
 196                         &priv, __alignof__(*ltt_chan), sizeof(*ltt_chan),
 197                         chan_priv_init,
 198                         buf_addr, subbuf_size, num_subbuf,
 199                         switch_timer_interval, read_timer_interval,
 200                         shm_fd, shm_path, wait_fd, wait_pipe_path,
 201                         memory_map_size);
 202         if (!handle)
 203                 return NULL;
 204         ltt_chan = priv;
 205         ltt_chan->handle = handle;
 206         ltt_chan->chan = shmp(ltt_chan->handle, ltt_chan->handle->chan);
 207         return ltt_chan;
 208 }
 209
 210 static
 211 void ltt_channel_destroy(struct ltt_channel *ltt_chan)
 212 {
 213         channel_destroy(ltt_chan->chan, ltt_chan->handle, 0);
 214 }
 215
 216 static
 217 struct lttng_ust_lib_ring_buffer *ltt_buffer_read_open(struct channel *chan,
 218                                                        struct lttng_ust_shm_handle *handle,
 219                                                        int **shm_fd, char **shm_path,
 220                                                        int **wait_fd, char **wait_pipe_path,
 221                                                        uint64_t **memory_map_size)
 222 {
 223         struct lttng_ust_lib_ring_buffer *buf;
 224
 225         buf = channel_get_ring_buffer(&client_config, chan,
 226                                       0, handle, shm_fd, shm_path,
 227                                       wait_fd, wait_pipe_path,
 228                                       memory_map_size);
 229         if (!lib_ring_buffer_open_read(buf, handle, 0))
 230                 return buf;
 231         return NULL;
 232 }
 233
 234 static
 235 void ltt_buffer_read_close(struct lttng_ust_lib_ring_buffer *buf,
 236                            struct lttng_ust_shm_handle *handle)
 237 {
 238         lib_ring_buffer_release_read(buf, handle, 0);
 239 }
 240
 241 static
 242 int ltt_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 243 {
 244         return lib_ring_buffer_reserve(&client_config, ctx);
 245 }
 246
 247 static
 248 void ltt_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 249 {
 250         lib_ring_buffer_commit(&client_config, ctx);
 251 }
 252
 253 static
 254 void ltt_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 255                      size_t len)
 256 {
 257         lib_ring_buffer_write(&client_config, ctx, src, len);
 258 }
 259
 260 static
 261 size_t ltt_packet_avail_size(struct channel *chan, struct lttng_ust_shm_handle *handle)
 262
 263 {
 264         unsigned long o_begin;
 265         struct lttng_ust_lib_ring_buffer *buf;
 266
 267         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 268         o_begin = v_read(&client_config, &buf->offset);
 269         if (subbuf_offset(o_begin, chan) != 0) {
 270                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 271         } else {
 272                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 273                         - sizeof(struct metadata_packet_header);
 274         }
 275 }
 276
 277 #if 0
 278 static
 279 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 280 {
 281         return &chan->read_wait;
 282 }
 283
 284 static
 285 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 286 {
 287         return &chan->hp_wait;
 288 }
 289 #endif //0
 290
 291 static
 292 int ltt_is_finalized(struct channel *chan)
 293 {
 294         return lib_ring_buffer_channel_is_finalized(chan);
 295 }
 296
 297 static
 298 int ltt_is_disabled(struct channel *chan)
 299 {
 300         return lib_ring_buffer_channel_is_disabled(chan);
 301 }
 302
 303 static
 304 int ltt_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 305 {
 306         struct lttng_ust_lib_ring_buffer *buf;
 307         int *shm_fd, *wait_fd;
 308         char *shm_path, *wait_pipe_path;
 309         uint64_t *memory_map_size;
 310
 311         buf = channel_get_ring_buffer(&client_config, chan,
 312                                       0, handle, &shm_fd, &shm_path,
 313                                       &wait_fd, &wait_pipe_path,
 314                                       &memory_map_size);
 315         lib_ring_buffer_switch(&client_config, buf,
 316                         SWITCH_ACTIVE, handle);
 317         return 0;
 318 }
 319
 320 static struct ltt_transport ltt_relay_transport = {
 321         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 322         .ops = {
 323                 .channel_create = _channel_create,
 324                 .channel_destroy = ltt_channel_destroy,
 325                 .buffer_read_open = ltt_buffer_read_open,
 326                 .buffer_read_close = ltt_buffer_read_close,
 327                 .event_reserve = ltt_event_reserve,
 328                 .event_commit = ltt_event_commit,
 329                 .event_write = ltt_event_write,
 330                 .packet_avail_size = ltt_packet_avail_size,
 331                 //.get_reader_wait_queue = ltt_get_reader_wait_queue,
 332                 //.get_hp_wait_queue = ltt_get_hp_wait_queue,
 333                 .is_finalized = ltt_is_finalized,
 334                 .is_disabled = ltt_is_disabled,
 335                 .flush_buffer = ltt_flush_buffer,
 336         },
 337 };
 338
 339 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 340 {
 341         DBG("LTT : ltt ring buffer client init\n");
 342         ltt_transport_register(&ltt_relay_transport);
 343 }
 344
 345 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 346 {
 347         DBG("LTT : ltt ring buffer client exit\n");
 348         ltt_transport_unregister(&ltt_relay_transport);
 349 }