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 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 lttng_channel *lttng_chan = channel_get_private(chan);
 102
 103         header->magic = TSDL_MAGIC_NUMBER;
 104         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_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  * 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 lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 120                               unsigned int subbuf_idx, unsigned long data_size,
 121                               struct lttng_ust_shm_handle *handle)
 122 {
 123         struct channel *chan = shmp(handle, buf->backend.chan);
 124         struct metadata_packet_header *header =
 125                 (struct metadata_packet_header *)
 126                         lib_ring_buffer_offset_address(&buf->backend,
 127                                 subbuf_idx * chan->backend.subbuf_size,
 128                                 handle);
 129         unsigned long records_lost = 0;
 130
 131         header->content_size = data_size * CHAR_BIT;            /* in bits */
 132         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 133         /*
 134          * We do not care about the records lost count, because the metadata
 135          * channel waits and retry.
 136          */
 137         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 138         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 139         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 140         WARN_ON_ONCE(records_lost != 0);
 141 }
 142
 143 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 144                                 int cpu, const char *name,
 145                                 struct lttng_ust_shm_handle *handle)
 146 {
 147         return 0;
 148 }
 149
 150 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 151                                    void *priv, int cpu,
 152                                    struct lttng_ust_shm_handle *handle)
 153 {
 154 }
 155
 156 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 157         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 158         .cb.record_header_size = client_record_header_size,
 159         .cb.subbuffer_header_size = client_packet_header_size,
 160         .cb.buffer_begin = client_buffer_begin,
 161         .cb.buffer_end = client_buffer_end,
 162         .cb.buffer_create = client_buffer_create,
 163         .cb.buffer_finalize = client_buffer_finalize,
 164
 165         .tsc_bits = 0,
 166         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 167         .sync = RING_BUFFER_SYNC_GLOBAL,
 168         .mode = RING_BUFFER_MODE_TEMPLATE,
 169         .backend = RING_BUFFER_PAGE,
 170         .output = RING_BUFFER_MMAP,
 171         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 172         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 173         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 174         .client_type = LTTNG_CLIENT_TYPE,
 175 };
 176
 177 const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
 178
 179 static
 180 struct lttng_channel *_channel_create(const char *name,
 181                                 void *buf_addr,
 182                                 size_t subbuf_size, size_t num_subbuf,
 183                                 unsigned int switch_timer_interval,
 184                                 unsigned int read_timer_interval,
 185                                 unsigned char *uuid)
 186 {
 187         struct lttng_channel chan_priv_init;
 188         struct lttng_ust_shm_handle *handle;
 189         struct lttng_channel *lttng_chan;
 190         void *priv;
 191
 192         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 193         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 194         handle = channel_create(&client_config, name,
 195                         &priv, __alignof__(*lttng_chan), sizeof(*lttng_chan),
 196                         &chan_priv_init,
 197                         buf_addr, subbuf_size, num_subbuf,
 198                         switch_timer_interval, read_timer_interval);
 199         if (!handle)
 200                 return NULL;
 201         lttng_chan = priv;
 202         lttng_chan->handle = handle;
 203         lttng_chan->chan = shmp(handle, handle->chan);
 204         return lttng_chan;
 205 }
 206
 207 static
 208 void lttng_channel_destroy(struct lttng_channel *chan)
 209 {
 210         channel_destroy(chan->chan, chan->handle, 1);
 211 }
 212
 213 static
 214 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 215 {
 216         return lib_ring_buffer_reserve(&client_config, ctx);
 217 }
 218
 219 static
 220 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 221 {
 222         lib_ring_buffer_commit(&client_config, ctx);
 223 }
 224
 225 static
 226 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 227                      size_t len)
 228 {
 229         lib_ring_buffer_write(&client_config, ctx, src, len);
 230 }
 231
 232 static
 233 size_t lttng_packet_avail_size(struct channel *chan, struct lttng_ust_shm_handle *handle)
 234
 235 {
 236         unsigned long o_begin;
 237         struct lttng_ust_lib_ring_buffer *buf;
 238
 239         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 240         o_begin = v_read(&client_config, &buf->offset);
 241         if (subbuf_offset(o_begin, chan) != 0) {
 242                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 243         } else {
 244                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 245                         - sizeof(struct metadata_packet_header);
 246         }
 247 }
 248
 249 #if 0
 250 static
 251 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 252 {
 253         return &chan->read_wait;
 254 }
 255
 256 static
 257 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 258 {
 259         return &chan->hp_wait;
 260 }
 261 #endif //0
 262
 263 static
 264 int lttng_is_finalized(struct channel *chan)
 265 {
 266         return lib_ring_buffer_channel_is_finalized(chan);
 267 }
 268
 269 static
 270 int lttng_is_disabled(struct channel *chan)
 271 {
 272         return lib_ring_buffer_channel_is_disabled(chan);
 273 }
 274
 275 static
 276 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 277 {
 278         struct lttng_ust_lib_ring_buffer *buf;
 279         int shm_fd, wait_fd, wakeup_fd;
 280         uint64_t memory_map_size;
 281
 282         buf = channel_get_ring_buffer(&client_config, chan,
 283                         0, handle, &shm_fd, &wait_fd, &wakeup_fd,
 284                         &memory_map_size);
 285         lib_ring_buffer_switch(&client_config, buf,
 286                         SWITCH_ACTIVE, handle);
 287         return 0;
 288 }
 289
 290 static struct lttng_transport lttng_relay_transport = {
 291         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 292         .ops = {
 293                 .channel_create = _channel_create,
 294                 .channel_destroy = lttng_channel_destroy,
 295                 .event_reserve = lttng_event_reserve,
 296                 .event_commit = lttng_event_commit,
 297                 .event_write = lttng_event_write,
 298                 .packet_avail_size = lttng_packet_avail_size,
 299                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 300                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 301                 .is_finalized = lttng_is_finalized,
 302                 .is_disabled = lttng_is_disabled,
 303                 .flush_buffer = lttng_flush_buffer,
 304         },
 305         .client_config = &client_config,
 306 };
 307
 308 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 309 {
 310         DBG("LTT : ltt ring buffer client init\n");
 311         lttng_transport_register(&lttng_relay_transport);
 312 }
 313
 314 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 315 {
 316         DBG("LTT : ltt ring buffer client exit\n");
 317         lttng_transport_unregister(&lttng_relay_transport);
 318 }