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 <linux/module.h>
  24 #include <linux/types.h>
  25 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  26 #include "lttng-events.h"
  27 #include "lttng-tracer.h"
  28
  29 struct metadata_packet_header {
  30         uint32_t magic;                 /* 0x75D11D57 */
  31         uint8_t  uuid[16];              /* 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 lib_ring_buffer_config client_config;
  48
  49 static inline
  50 u64 lib_ring_buffer_clock_read(struct channel *chan)
  51 {
  52         return 0;
  53 }
  54
  55 static inline
  56 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  57                                  struct channel *chan, size_t offset,
  58                                  size_t *pre_header_padding,
  59                                  struct lib_ring_buffer_ctx *ctx)
  60 {
  61         return 0;
  62 }
  63
  64 #include "wrapper/ringbuffer/api.h"
  65
  66 static u64 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 lib_ring_buffer_config *config,
  73                                  struct channel *chan, size_t offset,
  74                                  size_t *pre_header_padding,
  75                                  struct 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 lib_ring_buffer *buf, u64 tsc,
  93                                 unsigned int subbuf_idx)
  94 {
  95         struct channel *chan = 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         struct lttng_channel *lttng_chan = channel_get_private(chan);
 101         struct lttng_session *session = lttng_chan->session;
 102
 103         header->magic = TSDL_MAGIC_NUMBER;
 104         memcpy(header->uuid, session->uuid.b, sizeof(session->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  * offset is assumed to never be 0 here : never deliver a completely empty
 117  * subbuffer. data_size is between 1 and subbuf_size.
 118  */
 119 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 120                               unsigned int subbuf_idx, unsigned long data_size)
 121 {
 122         struct channel *chan = buf->backend.chan;
 123         struct metadata_packet_header *header =
 124                 (struct metadata_packet_header *)
 125                         lib_ring_buffer_offset_address(&buf->backend,
 126                                 subbuf_idx * chan->backend.subbuf_size);
 127         unsigned long records_lost = 0;
 128
 129         header->content_size = data_size * CHAR_BIT;            /* in bits */
 130         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 131         /*
 132          * We do not care about the records lost count, because the metadata
 133          * channel waits and retry.
 134          */
 135         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 136         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 137         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 138         WARN_ON_ONCE(records_lost != 0);
 139 }
 140
 141 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 142                                 int cpu, const char *name)
 143 {
 144         return 0;
 145 }
 146
 147 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 148 {
 149 }
 150
 151 static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
 152                 struct lib_ring_buffer *buf, uint64_t *timestamp_begin)
 153 {
 154         return -ENOSYS;
 155 }
 156
 157 static int client_timestamp_end(const struct lib_ring_buffer_config *config,
 158                         struct lib_ring_buffer *bufb,
 159                         uint64_t *timestamp_end)
 160 {
 161         return -ENOSYS;
 162 }
 163
 164 static int client_events_discarded(const struct lib_ring_buffer_config *config,
 165                         struct lib_ring_buffer *bufb,
 166                         uint64_t *events_discarded)
 167 {
 168         return -ENOSYS;
 169 }
 170
 171 static int client_content_size(const struct lib_ring_buffer_config *config,
 172                         struct lib_ring_buffer *bufb,
 173                         uint64_t *content_size)
 174 {
 175         return -ENOSYS;
 176 }
 177
 178 static int client_packet_size(const struct lib_ring_buffer_config *config,
 179                         struct lib_ring_buffer *bufb,
 180                         uint64_t *packet_size)
 181 {
 182         return -ENOSYS;
 183 }
 184
 185 static int client_stream_id(const struct lib_ring_buffer_config *config,
 186                         struct lib_ring_buffer *bufb,
 187                         uint64_t *stream_id)
 188 {
 189         return -ENOSYS;
 190 }
 191
 192 static const struct lib_ring_buffer_config client_config = {
 193         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 194         .cb.record_header_size = client_record_header_size,
 195         .cb.subbuffer_header_size = client_packet_header_size,
 196         .cb.buffer_begin = client_buffer_begin,
 197         .cb.buffer_end = client_buffer_end,
 198         .cb.buffer_create = client_buffer_create,
 199         .cb.buffer_finalize = client_buffer_finalize,
 200
 201         .tsc_bits = 0,
 202         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 203         .sync = RING_BUFFER_SYNC_GLOBAL,
 204         .mode = RING_BUFFER_MODE_TEMPLATE,
 205         .backend = RING_BUFFER_PAGE,
 206         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 207         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 208         .ipi = RING_BUFFER_IPI_BARRIER,
 209         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 210 };
 211
 212 static
 213 struct channel *_channel_create(const char *name,
 214                                 struct lttng_channel *lttng_chan, void *buf_addr,
 215                                 size_t subbuf_size, size_t num_subbuf,
 216                                 unsigned int switch_timer_interval,
 217                                 unsigned int read_timer_interval)
 218 {
 219         lttng_chan->ops->timestamp_begin = client_timestamp_begin;
 220         lttng_chan->ops->timestamp_end = client_timestamp_end;
 221         lttng_chan->ops->events_discarded = client_events_discarded;
 222         lttng_chan->ops->content_size = client_content_size;
 223         lttng_chan->ops->packet_size = client_packet_size;
 224         lttng_chan->ops->stream_id = client_stream_id;
 225
 226         return channel_create(&client_config, name, lttng_chan, buf_addr,
 227                               subbuf_size, num_subbuf, switch_timer_interval,
 228                               read_timer_interval);
 229 }
 230
 231 static
 232 void lttng_channel_destroy(struct channel *chan)
 233 {
 234         channel_destroy(chan);
 235 }
 236
 237 static
 238 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 239 {
 240         struct lib_ring_buffer *buf;
 241
 242         buf = channel_get_ring_buffer(&client_config, chan, 0);
 243         if (!lib_ring_buffer_open_read(buf))
 244                 return buf;
 245         return NULL;
 246 }
 247
 248 static
 249 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 250 {
 251         struct lib_ring_buffer *buf;
 252         int cpu;
 253
 254         for_each_channel_cpu(cpu, chan) {
 255                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 256                 if (!atomic_long_read(&buf->active_readers))
 257                         return 1;
 258         }
 259         return 0;
 260 }
 261
 262 static
 263 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 264 {
 265         lib_ring_buffer_release_read(buf);
 266 }
 267
 268 static
 269 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 270 {
 271         return lib_ring_buffer_reserve(&client_config, ctx);
 272 }
 273
 274 static
 275 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 276 {
 277         lib_ring_buffer_commit(&client_config, ctx);
 278 }
 279
 280 static
 281 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 282                      size_t len)
 283 {
 284         lib_ring_buffer_write(&client_config, ctx, src, len);
 285 }
 286
 287 static
 288 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 289                                const void __user *src, size_t len)
 290 {
 291         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 292 }
 293
 294 static
 295 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 296                 int c, size_t len)
 297 {
 298         lib_ring_buffer_memset(&client_config, ctx, c, len);
 299 }
 300
 301 static
 302 size_t lttng_packet_avail_size(struct channel *chan)
 303
 304 {
 305         unsigned long o_begin;
 306         struct lib_ring_buffer *buf;
 307
 308         buf = chan->backend.buf;        /* Only for global buffer ! */
 309         o_begin = v_read(&client_config, &buf->offset);
 310         if (subbuf_offset(o_begin, chan) != 0) {
 311                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 312         } else {
 313                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 314                         - sizeof(struct metadata_packet_header);
 315         }
 316 }
 317
 318 static
 319 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 320 {
 321         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 322                                         chan, cpu);
 323         return &buf->write_wait;
 324 }
 325
 326 static
 327 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 328 {
 329         return &chan->hp_wait;
 330 }
 331
 332 static
 333 int lttng_is_finalized(struct channel *chan)
 334 {
 335         return lib_ring_buffer_channel_is_finalized(chan);
 336 }
 337
 338 static
 339 int lttng_is_disabled(struct channel *chan)
 340 {
 341         return lib_ring_buffer_channel_is_disabled(chan);
 342 }
 343
 344 static struct lttng_transport lttng_relay_transport = {
 345         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 346         .owner = THIS_MODULE,
 347         .ops = {
 348                 .channel_create = _channel_create,
 349                 .channel_destroy = lttng_channel_destroy,
 350                 .buffer_read_open = lttng_buffer_read_open,
 351                 .buffer_has_read_closed_stream =
 352                         lttng_buffer_has_read_closed_stream,
 353                 .buffer_read_close = lttng_buffer_read_close,
 354                 .event_reserve = lttng_event_reserve,
 355                 .event_commit = lttng_event_commit,
 356                 .event_write_from_user = lttng_event_write_from_user,
 357                 .event_memset = lttng_event_memset,
 358                 .event_write = lttng_event_write,
 359                 .packet_avail_size = lttng_packet_avail_size,
 360                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 361                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 362                 .is_finalized = lttng_is_finalized,
 363                 .is_disabled = lttng_is_disabled,
 364         },
 365 };
 366
 367 static int __init lttng_ring_buffer_client_init(void)
 368 {
 369         /*
 370          * This vmalloc sync all also takes care of the lib ring buffer
 371          * vmalloc'd module pages when it is built as a module into LTTng.
 372          */
 373         wrapper_vmalloc_sync_all();
 374         lttng_transport_register(&lttng_relay_transport);
 375         return 0;
 376 }
 377
 378 module_init(lttng_ring_buffer_client_init);
 379
 380 static void __exit lttng_ring_buffer_client_exit(void)
 381 {
 382         lttng_transport_unregister(&lttng_relay_transport);
 383 }
 384
 385 module_exit(lttng_ring_buffer_client_exit);
 386
 387 MODULE_LICENSE("GPL and additional rights");
 388 MODULE_AUTHOR("Mathieu Desnoyers");
 389 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 390                    " client");