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

   1 /*
   2  * ltt-ring-buffer-client.h
   3  *
   4  * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  *
   8  * Dual LGPL v2.1/GPL v2 license.
   9  */
  10
  11 #define _GNU_SOURCE
  12 #include <stdint.h>
  13 #include <lttng/ust-events.h>
  14 #include "lttng/bitfield.h"
  15 #include "ltt-tracer.h"
  16 #include "../libringbuffer/frontend_types.h"
  17
  18 struct metadata_packet_header {
  19         uint32_t magic;                 /* 0x75D11D57 */
  20         uint8_t  uuid[16];              /* Unique Universal Identifier */
  21         uint32_t checksum;              /* 0 if unused */
  22         uint32_t content_size;          /* in bits */
  23         uint32_t packet_size;           /* in bits */
  24         uint8_t  compression_scheme;    /* 0 if unused */
  25         uint8_t  encryption_scheme;     /* 0 if unused */
  26         uint8_t  checksum_scheme;       /* 0 if unused */
  27         uint8_t  major;                 /* CTF spec major version number */
  28         uint8_t  minor;                 /* CTF spec minor version number */
  29         uint8_t  header_end[0];
  30 };
  31
  32 struct metadata_record_header {
  33         uint8_t header_end[0];          /* End of header */
  34 };
  35
  36 static const struct lttng_ust_lib_ring_buffer_config client_config;
  37
  38 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  39 {
  40         return 0;
  41 }
  42
  43 static inline
  44 unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  45                                  struct channel *chan, size_t offset,
  46                                  size_t *pre_header_padding,
  47                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
  48 {
  49         return 0;
  50 }
  51
  52 #include "../libringbuffer/api.h"
  53
  54 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
  55 {
  56         return 0;
  57 }
  58
  59 static
  60 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  61                                  struct channel *chan, size_t offset,
  62                                  size_t *pre_header_padding,
  63                                  struct lttng_ust_lib_ring_buffer_ctx *ctx)
  64 {
  65         return 0;
  66 }
  67
  68 /**
  69  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  70  *
  71  * Return header size without padding after the structure. Don't use packed
  72  * structure because gcc generates inefficient code on some architectures
  73  * (powerpc, mips..)
  74  */
  75 static size_t client_packet_header_size(void)
  76 {
  77         return offsetof(struct metadata_packet_header, header_end);
  78 }
  79
  80 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
  81                                 unsigned int subbuf_idx,
  82                                 struct lttng_ust_shm_handle *handle)
  83 {
  84         struct channel *chan = shmp(handle, buf->backend.chan);
  85         struct metadata_packet_header *header =
  86                 (struct metadata_packet_header *)
  87                         lib_ring_buffer_offset_address(&buf->backend,
  88                                 subbuf_idx * chan->backend.subbuf_size,
  89                                 handle);
  90         struct ltt_channel *ltt_chan = channel_get_private(chan);
  91
  92         header->magic = TSDL_MAGIC_NUMBER;
  93         memcpy(header->uuid, ltt_chan->uuid, sizeof(ltt_chan->uuid));
  94         header->checksum = 0;           /* 0 if unused */
  95         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  96         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  97         header->compression_scheme = 0; /* 0 if unused */
  98         header->encryption_scheme = 0;  /* 0 if unused */
  99         header->checksum_scheme = 0;    /* 0 if unused */
 100         header->major = CTF_SPEC_MAJOR;
 101         header->minor = CTF_SPEC_MINOR;
 102
 103 }
 104
 105 /*
 106  * offset is assumed to never be 0 here : never deliver a completely empty
 107  * subbuffer. data_size is between 1 and subbuf_size.
 108  */
 109 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 110                               unsigned int subbuf_idx, unsigned long data_size,
 111                               struct lttng_ust_shm_handle *handle)
 112 {
 113         struct channel *chan = shmp(handle, buf->backend.chan);
 114         struct metadata_packet_header *header =
 115                 (struct metadata_packet_header *)
 116                         lib_ring_buffer_offset_address(&buf->backend,
 117                                 subbuf_idx * chan->backend.subbuf_size,
 118                                 handle);
 119         unsigned long records_lost = 0;
 120
 121         header->content_size = data_size * CHAR_BIT;            /* in bits */
 122         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 123         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 124         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 125         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 126         WARN_ON_ONCE(records_lost != 0);
 127 }
 128
 129 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 130                                 int cpu, const char *name,
 131                                 struct lttng_ust_shm_handle *handle)
 132 {
 133         return 0;
 134 }
 135
 136 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 137                                    void *priv, int cpu,
 138                                    struct lttng_ust_shm_handle *handle)
 139 {
 140 }
 141
 142 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 143         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 144         .cb.record_header_size = client_record_header_size,
 145         .cb.subbuffer_header_size = client_packet_header_size,
 146         .cb.buffer_begin = client_buffer_begin,
 147         .cb.buffer_end = client_buffer_end,
 148         .cb.buffer_create = client_buffer_create,
 149         .cb.buffer_finalize = client_buffer_finalize,
 150
 151         .tsc_bits = 0,
 152         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 153         .sync = RING_BUFFER_SYNC_GLOBAL,
 154         .mode = RING_BUFFER_MODE_TEMPLATE,
 155         .backend = RING_BUFFER_PAGE,
 156         .output = RING_BUFFER_MMAP,
 157         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 158         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 159         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 160         .client_type = LTTNG_CLIENT_TYPE,
 161 };
 162
 163 const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
 164
 165 static
 166 struct ltt_channel *_channel_create(const char *name,
 167                                 void *buf_addr,
 168                                 size_t subbuf_size, size_t num_subbuf,
 169                                 unsigned int switch_timer_interval,
 170                                 unsigned int read_timer_interval,
 171                                 int **shm_fd, int **wait_fd,
 172                                 uint64_t **memory_map_size,
 173                                 struct ltt_channel *chan_priv_init)
 174 {
 175         void *priv;
 176         struct ltt_channel *ltt_chan = NULL;
 177         struct lttng_ust_shm_handle *handle;
 178
 179         handle = channel_create(&client_config, name,
 180                         &priv, __alignof__(*ltt_chan), sizeof(*ltt_chan),
 181                         chan_priv_init,
 182                         buf_addr, subbuf_size, num_subbuf,
 183                         switch_timer_interval, read_timer_interval,
 184                         shm_fd, wait_fd, memory_map_size);
 185         if (!handle)
 186                 return NULL;
 187         ltt_chan = priv;
 188         ltt_chan->handle = handle;
 189         ltt_chan->chan = shmp(ltt_chan->handle, ltt_chan->handle->chan);
 190         return ltt_chan;
 191 }
 192
 193 static
 194 void ltt_channel_destroy(struct ltt_channel *ltt_chan)
 195 {
 196         channel_destroy(ltt_chan->chan, ltt_chan->handle, 0);
 197 }
 198
 199 static
 200 struct lttng_ust_lib_ring_buffer *ltt_buffer_read_open(struct channel *chan,
 201                                              struct lttng_ust_shm_handle *handle,
 202                                              int **shm_fd, int **wait_fd,
 203                                              uint64_t **memory_map_size)
 204 {
 205         struct lttng_ust_lib_ring_buffer *buf;
 206
 207         buf = channel_get_ring_buffer(&client_config, chan,
 208                         0, handle, shm_fd, wait_fd, memory_map_size);
 209         if (!lib_ring_buffer_open_read(buf, handle, 0))
 210                 return buf;
 211         return NULL;
 212 }
 213
 214 static
 215 void ltt_buffer_read_close(struct lttng_ust_lib_ring_buffer *buf,
 216                            struct lttng_ust_shm_handle *handle)
 217 {
 218         lib_ring_buffer_release_read(buf, handle, 0);
 219 }
 220
 221 static
 222 int ltt_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 223 {
 224         return lib_ring_buffer_reserve(&client_config, ctx);
 225 }
 226
 227 static
 228 void ltt_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 229 {
 230         lib_ring_buffer_commit(&client_config, ctx);
 231 }
 232
 233 static
 234 void ltt_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 235                      size_t len)
 236 {
 237         lib_ring_buffer_write(&client_config, ctx, src, len);
 238 }
 239
 240 static
 241 size_t ltt_packet_avail_size(struct channel *chan, struct lttng_ust_shm_handle *handle)
 242
 243 {
 244         unsigned long o_begin;
 245         struct lttng_ust_lib_ring_buffer *buf;
 246
 247         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 248         o_begin = v_read(&client_config, &buf->offset);
 249         if (subbuf_offset(o_begin, chan) != 0) {
 250                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 251         } else {
 252                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 253                         - sizeof(struct metadata_packet_header);
 254         }
 255 }
 256
 257 #if 0
 258 static
 259 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 260 {
 261         return &chan->read_wait;
 262 }
 263
 264 static
 265 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 266 {
 267         return &chan->hp_wait;
 268 }
 269 #endif //0
 270
 271 static
 272 int ltt_is_finalized(struct channel *chan)
 273 {
 274         return lib_ring_buffer_channel_is_finalized(chan);
 275 }
 276
 277 static
 278 int ltt_is_disabled(struct channel *chan)
 279 {
 280         return lib_ring_buffer_channel_is_disabled(chan);
 281 }
 282
 283 static
 284 int ltt_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 285 {
 286         struct lttng_ust_lib_ring_buffer *buf;
 287         int *shm_fd, *wait_fd;
 288         uint64_t *memory_map_size;
 289
 290         buf = channel_get_ring_buffer(&client_config, chan,
 291                         0, handle, &shm_fd, &wait_fd,
 292                         &memory_map_size);
 293         lib_ring_buffer_switch(&client_config, buf,
 294                         SWITCH_ACTIVE, handle);
 295         return 0;
 296 }
 297
 298 static struct ltt_transport ltt_relay_transport = {
 299         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 300         .ops = {
 301                 .channel_create = _channel_create,
 302                 .channel_destroy = ltt_channel_destroy,
 303                 .buffer_read_open = ltt_buffer_read_open,
 304                 .buffer_read_close = ltt_buffer_read_close,
 305                 .event_reserve = ltt_event_reserve,
 306                 .event_commit = ltt_event_commit,
 307                 .event_write = ltt_event_write,
 308                 .packet_avail_size = ltt_packet_avail_size,
 309                 //.get_reader_wait_queue = ltt_get_reader_wait_queue,
 310                 //.get_hp_wait_queue = ltt_get_hp_wait_queue,
 311                 .is_finalized = ltt_is_finalized,
 312                 .is_disabled = ltt_is_disabled,
 313                 .flush_buffer = ltt_flush_buffer,
 314         },
 315 };
 316
 317 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 318 {
 319         DBG("LTT : ltt ring buffer client init\n");
 320         ltt_transport_register(&ltt_relay_transport);
 321 }
 322
 323 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 324 {
 325         DBG("LTT : ltt ring buffer client exit\n");
 326         ltt_transport_unregister(&ltt_relay_transport);
 327 }