libust/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 #include <stdint.h>
  12 #include <ust/lttng-events.h>
  13 #include "ust/bitfield.h"
  14 #include "ltt-tracer.h"
  15 #include "../libringbuffer/frontend_types.h"
  16
  17 struct metadata_packet_header {
  18         uint32_t magic;                 /* 0x75D11D57 */
  19         uint8_t  uuid[16];              /* Unique Universal Identifier */
  20         uint32_t checksum;              /* 0 if unused */
  21         uint32_t content_size;          /* in bits */
  22         uint32_t packet_size;           /* in bits */
  23         uint8_t  compression_scheme;    /* 0 if unused */
  24         uint8_t  encryption_scheme;     /* 0 if unused */
  25         uint8_t  checksum_scheme;       /* 0 if unused */
  26         uint8_t  header_end[0];
  27 };
  28
  29 struct metadata_record_header {
  30         uint8_t header_end[0];          /* End of header */
  31 };
  32
  33 static const struct lib_ring_buffer_config client_config;
  34
  35 static inline
  36 u64 lib_ring_buffer_clock_read(struct channel *chan)
  37 {
  38         return 0;
  39 }
  40
  41 static inline
  42 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  43                                  struct channel *chan, size_t offset,
  44                                  size_t *pre_header_padding,
  45                                  struct lib_ring_buffer_ctx *ctx)
  46 {
  47         return 0;
  48 }
  49
  50 #include "../libringbuffer/api.h"
  51
  52 static u64 client_ring_buffer_clock_read(struct channel *chan)
  53 {
  54         return 0;
  55 }
  56
  57 static
  58 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  59                                  struct channel *chan, size_t offset,
  60                                  size_t *pre_header_padding,
  61                                  struct lib_ring_buffer_ctx *ctx)
  62 {
  63         return 0;
  64 }
  65
  66 /**
  67  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  68  *
  69  * Return header size without padding after the structure. Don't use packed
  70  * structure because gcc generates inefficient code on some architectures
  71  * (powerpc, mips..)
  72  */
  73 static size_t client_packet_header_size(void)
  74 {
  75         return offsetof(struct metadata_packet_header, header_end);
  76 }
  77
  78 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  79                                 unsigned int subbuf_idx,
  80                                 struct shm_handle *handle)
  81 {
  82         struct channel *chan = shmp(handle, buf->backend.chan);
  83         struct metadata_packet_header *header =
  84                 (struct metadata_packet_header *)
  85                         lib_ring_buffer_offset_address(&buf->backend,
  86                                 subbuf_idx * chan->backend.subbuf_size,
  87                                 handle);
  88         struct ltt_channel *ltt_chan = channel_get_private(chan);
  89         struct ltt_session *session = ltt_chan->session;
  90
  91         header->magic = TSDL_MAGIC_NUMBER;
  92         memcpy(header->uuid, session->uuid, sizeof(session->uuid));
  93         header->checksum = 0;           /* 0 if unused */
  94         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  95         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  96         header->compression_scheme = 0; /* 0 if unused */
  97         header->encryption_scheme = 0;  /* 0 if unused */
  98         header->checksum_scheme = 0;    /* 0 if unused */
  99 }
 100
 101 /*
 102  * offset is assumed to never be 0 here : never deliver a completely empty
 103  * subbuffer. data_size is between 1 and subbuf_size.
 104  */
 105 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 106                               unsigned int subbuf_idx, unsigned long data_size,
 107                               struct shm_handle *handle)
 108 {
 109         struct channel *chan = shmp(handle, buf->backend.chan);
 110         struct metadata_packet_header *header =
 111                 (struct metadata_packet_header *)
 112                         lib_ring_buffer_offset_address(&buf->backend,
 113                                 subbuf_idx * chan->backend.subbuf_size,
 114                                 handle);
 115         unsigned long records_lost = 0;
 116
 117         header->content_size = data_size * CHAR_BIT;            /* in bits */
 118         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 119         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 120         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 121         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 122         WARN_ON_ONCE(records_lost != 0);
 123 }
 124
 125 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 126                                 int cpu, const char *name,
 127                                 struct shm_handle *handle)
 128 {
 129         return 0;
 130 }
 131
 132 static void client_buffer_finalize(struct lib_ring_buffer *buf,
 133                                    void *priv, int cpu,
 134                                    struct shm_handle *handle)
 135 {
 136 }
 137
 138 static const struct lib_ring_buffer_config client_config = {
 139         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 140         .cb.record_header_size = client_record_header_size,
 141         .cb.subbuffer_header_size = client_packet_header_size,
 142         .cb.buffer_begin = client_buffer_begin,
 143         .cb.buffer_end = client_buffer_end,
 144         .cb.buffer_create = client_buffer_create,
 145         .cb.buffer_finalize = client_buffer_finalize,
 146
 147         .tsc_bits = 0,
 148         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 149         .sync = RING_BUFFER_SYNC_GLOBAL,
 150         .mode = RING_BUFFER_MODE_TEMPLATE,
 151         .backend = RING_BUFFER_PAGE,
 152         .output = RING_BUFFER_MMAP,
 153         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 154         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 155         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 156 };
 157
 158 static
 159 struct ltt_channel *_channel_create(const char *name,
 160                                 struct ltt_channel *ltt_chan, void *buf_addr,
 161                                 size_t subbuf_size, size_t num_subbuf,
 162                                 unsigned int switch_timer_interval,
 163                                 unsigned int read_timer_interval)
 164 {
 165         ltt_chan->handle = channel_create(&client_config, name, ltt_chan, buf_addr,
 166                               subbuf_size, num_subbuf, switch_timer_interval,
 167                               read_timer_interval);
 168         ltt_chan->chan = shmp(handle, handle->chan);
 169         return ltt_chan;
 170 }
 171
 172 static
 173 void ltt_channel_destroy(struct ltt_channel *ltt_chan)
 174 {
 175         channel_destroy(ltt_chan->chan, ltt_chan->handle);
 176 }
 177
 178 static
 179 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan,
 180                                              struct shm_handle *handle)
 181 {
 182         struct lib_ring_buffer *buf;
 183
 184         buf = channel_get_ring_buffer(&client_config, chan, 0, handle);
 185         if (!lib_ring_buffer_open_read(buf, handle))
 186                 return buf;
 187         return NULL;
 188 }
 189
 190 static
 191 void ltt_buffer_read_close(struct lib_ring_buffer *buf,
 192                            struct shm_handle *handle)
 193 {
 194         lib_ring_buffer_release_read(buf, handle);
 195 }
 196
 197 static
 198 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 199 {
 200         return lib_ring_buffer_reserve(&client_config, ctx);
 201 }
 202
 203 static
 204 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 205 {
 206         lib_ring_buffer_commit(&client_config, ctx);
 207 }
 208
 209 static
 210 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 211                      size_t len)
 212 {
 213         lib_ring_buffer_write(&client_config, ctx, src, len);
 214 }
 215
 216 static
 217 size_t ltt_packet_avail_size(struct channel *chan, struct shm_handle *handle)
 218
 219 {
 220         unsigned long o_begin;
 221         struct lib_ring_buffer *buf;
 222
 223         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 224         o_begin = v_read(&client_config, &buf->offset);
 225         if (subbuf_offset(o_begin, chan) != 0) {
 226                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 227         } else {
 228                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 229                         - sizeof(struct metadata_packet_header);
 230         }
 231 }
 232
 233 #if 0
 234 static
 235 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 236 {
 237         return &chan->read_wait;
 238 }
 239
 240 static
 241 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 242 {
 243         return &chan->hp_wait;
 244 }
 245 #endif //0
 246
 247 static
 248 int ltt_is_finalized(struct channel *chan)
 249 {
 250         return lib_ring_buffer_channel_is_finalized(chan);
 251 }
 252
 253 static
 254 int ltt_is_disabled(struct channel *chan)
 255 {
 256         return lib_ring_buffer_channel_is_disabled(chan);
 257 }
 258
 259 static struct ltt_transport ltt_relay_transport = {
 260         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 261         .ops = {
 262                 .channel_create = _channel_create,
 263                 .channel_destroy = ltt_channel_destroy,
 264                 .buffer_read_open = ltt_buffer_read_open,
 265                 .buffer_read_close = ltt_buffer_read_close,
 266                 .event_reserve = ltt_event_reserve,
 267                 .event_commit = ltt_event_commit,
 268                 .event_write = ltt_event_write,
 269                 .packet_avail_size = ltt_packet_avail_size,
 270                 //.get_reader_wait_queue = ltt_get_reader_wait_queue,
 271                 //.get_hp_wait_queue = ltt_get_hp_wait_queue,
 272                 .is_finalized = ltt_is_finalized,
 273                 .is_disabled = ltt_is_disabled,
 274         },
 275 };
 276
 277 static
 278 void __attribute__((constructor)) ltt_ring_buffer_client_init(void)
 279 {
 280         DBG("LTT : ltt ring buffer client init\n");
 281         ltt_transport_register(&ltt_relay_transport);
 282 }
 283
 284 static
 285 void __attribute__((destructor)) ltt_ring_buffer_client_exit(void)
 286 {
 287         DBG("LTT : ltt ring buffer client exit\n");
 288         ltt_transport_unregister(&ltt_relay_transport);
 289 }