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

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  */
   8
   9 #include <stddef.h>
  10 #include <stdint.h>
  11
  12 #include <ust-events-internal.h>
  13 #include "ust-bitfield.h"
  14 #include "ust-compat.h"
  15 #include "lttng-tracer.h"
  16 #include "../libringbuffer/frontend_types.h"
  17
  18 struct metadata_packet_header {
  19         uint32_t magic;                 /* 0x75D11D57 */
  20         uint8_t  uuid[LTTNG_UST_UUID_LEN]; /* 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 lttng_ust_lib_ring_buffer_channel *chan)
  39 {
  40         return 0;
  41 }
  42
  43 static inline
  44 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  45                                  struct lttng_ust_lib_ring_buffer_channel *chan,
  46                                  size_t offset,
  47                                  size_t *pre_header_padding,
  48                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  49                                  void *client_ctx)
  50 {
  51         return 0;
  52 }
  53
  54 #include "../libringbuffer/api.h"
  55 #include "lttng-rb-clients.h"
  56
  57 static uint64_t client_ring_buffer_clock_read(struct lttng_ust_lib_ring_buffer_channel *chan)
  58 {
  59         return 0;
  60 }
  61
  62 static
  63 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  64                                  struct lttng_ust_lib_ring_buffer_channel *chan,
  65                                  size_t offset,
  66                                  size_t *pre_header_padding,
  67                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  68                                  void *client_ctx)
  69 {
  70         return 0;
  71 }
  72
  73 /**
  74  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  75  *
  76  * Return header size without padding after the structure. Don't use packed
  77  * structure because gcc generates inefficient code on some architectures
  78  * (powerpc, mips..)
  79  */
  80 static size_t client_packet_header_size(void)
  81 {
  82         return offsetof(struct metadata_packet_header, header_end);
  83 }
  84
  85 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
  86                                 unsigned int subbuf_idx,
  87                                 struct lttng_ust_shm_handle *handle)
  88 {
  89         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
  90         struct metadata_packet_header *header =
  91                 (struct metadata_packet_header *)
  92                         lib_ring_buffer_offset_address(&buf->backend,
  93                                 subbuf_idx * chan->backend.subbuf_size,
  94                                 handle);
  95         struct lttng_channel *lttng_chan = channel_get_private(chan);
  96
  97         assert(header);
  98         if (!header)
  99                 return;
 100         header->magic = TSDL_MAGIC_NUMBER;
 101         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
 102         header->checksum = 0;           /* 0 if unused */
 103         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 104         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 105         header->compression_scheme = 0; /* 0 if unused */
 106         header->encryption_scheme = 0;  /* 0 if unused */
 107         header->checksum_scheme = 0;    /* 0 if unused */
 108         header->major = CTF_SPEC_MAJOR;
 109         header->minor = CTF_SPEC_MINOR;
 110 }
 111
 112 /*
 113  * offset is assumed to never be 0 here : never deliver a completely empty
 114  * subbuffer. data_size is between 1 and subbuf_size.
 115  */
 116 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 117                               unsigned int subbuf_idx, unsigned long data_size,
 118                               struct lttng_ust_shm_handle *handle)
 119 {
 120         struct lttng_ust_lib_ring_buffer_channel *chan = shmp(handle, buf->backend.chan);
 121         struct metadata_packet_header *header =
 122                 (struct metadata_packet_header *)
 123                         lib_ring_buffer_offset_address(&buf->backend,
 124                                 subbuf_idx * chan->backend.subbuf_size,
 125                                 handle);
 126         unsigned long records_lost = 0;
 127
 128         assert(header);
 129         if (!header)
 130                 return;
 131         header->content_size = data_size * CHAR_BIT;            /* in bits */
 132         header->packet_size = LTTNG_UST_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
 157 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 158         .parent = {
 159                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 160                 .record_header_size = client_record_header_size,
 161                 .subbuffer_header_size = client_packet_header_size,
 162                 .buffer_begin = client_buffer_begin,
 163                 .buffer_end = client_buffer_end,
 164                 .buffer_create = client_buffer_create,
 165                 .buffer_finalize = client_buffer_finalize,
 166         },
 167 };
 168
 169 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 170         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 171         .cb.record_header_size = client_record_header_size,
 172         .cb.subbuffer_header_size = client_packet_header_size,
 173         .cb.buffer_begin = client_buffer_begin,
 174         .cb.buffer_end = client_buffer_end,
 175         .cb.buffer_create = client_buffer_create,
 176         .cb.buffer_finalize = client_buffer_finalize,
 177
 178         .tsc_bits = 0,
 179         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 180         .sync = RING_BUFFER_SYNC_GLOBAL,
 181         .mode = RING_BUFFER_MODE_TEMPLATE,
 182         .backend = RING_BUFFER_PAGE,
 183         .output = RING_BUFFER_MMAP,
 184         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 185         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 186         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 187         .client_type = LTTNG_CLIENT_TYPE,
 188
 189          .cb_ptr = &client_cb.parent,
 190 };
 191
 192 static
 193 struct lttng_channel *_channel_create(const char *name,
 194                                 void *buf_addr,
 195                                 size_t subbuf_size, size_t num_subbuf,
 196                                 unsigned int switch_timer_interval,
 197                                 unsigned int read_timer_interval,
 198                                 unsigned char *uuid,
 199                                 uint32_t chan_id,
 200                                 const int *stream_fds, int nr_stream_fds,
 201                                 int64_t blocking_timeout)
 202 {
 203         struct lttng_channel chan_priv_init;
 204         struct lttng_ust_shm_handle *handle;
 205         struct lttng_channel *lttng_chan;
 206         void *priv;
 207
 208         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 209         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 210         chan_priv_init.id = chan_id;
 211         handle = channel_create(&client_config, name,
 212                         &priv, __alignof__(struct lttng_channel),
 213                         sizeof(struct lttng_channel),
 214                         &chan_priv_init,
 215                         buf_addr, subbuf_size, num_subbuf,
 216                         switch_timer_interval, read_timer_interval,
 217                         stream_fds, nr_stream_fds, blocking_timeout);
 218         if (!handle)
 219                 return NULL;
 220         lttng_chan = priv;
 221         lttng_chan->handle = handle;
 222         lttng_chan->chan = shmp(handle, handle->chan);
 223         return lttng_chan;
 224 }
 225
 226 static
 227 void lttng_channel_destroy(struct lttng_channel *chan)
 228 {
 229         channel_destroy(chan->chan, chan->handle, 1);
 230 }
 231
 232 static
 233 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 234 {
 235         int ret;
 236
 237         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 238         if (ret)
 239                 return ret;
 240         if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 241                         &ctx->backend_pages))
 242                 return -EPERM;
 243         return 0;
 244 }
 245
 246 static
 247 void lttng_event_commit(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 248 {
 249         lib_ring_buffer_commit(&client_config, ctx);
 250 }
 251
 252 static
 253 void lttng_event_write(struct lttng_ust_lib_ring_buffer_ctx *ctx, const void *src,
 254                      size_t len)
 255 {
 256         lib_ring_buffer_write(&client_config, ctx, src, len);
 257 }
 258
 259 static
 260 size_t lttng_packet_avail_size(struct lttng_ust_lib_ring_buffer_channel *chan,
 261                 struct lttng_ust_shm_handle *handle)
 262 {
 263         unsigned long o_begin;
 264         struct lttng_ust_lib_ring_buffer *buf;
 265
 266         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 267         o_begin = v_read(&client_config, &buf->offset);
 268         if (subbuf_offset(o_begin, chan) != 0) {
 269                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 270         } else {
 271                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 272                         - sizeof(struct metadata_packet_header);
 273         }
 274 }
 275
 276 #if 0
 277 static
 278 wait_queue_head_t *lttng_get_reader_wait_queue(struct lttng_ust_lib_ring_buffer_channel *chan)
 279 {
 280         return &chan->read_wait;
 281 }
 282
 283 static
 284 wait_queue_head_t *lttng_get_hp_wait_queue(struct lttng_ust_lib_ring_buffer_channel *chan)
 285 {
 286         return &chan->hp_wait;
 287 }
 288 #endif //0
 289
 290 static
 291 int lttng_is_finalized(struct lttng_ust_lib_ring_buffer_channel *chan)
 292 {
 293         return lib_ring_buffer_channel_is_finalized(chan);
 294 }
 295
 296 static
 297 int lttng_is_disabled(struct lttng_ust_lib_ring_buffer_channel *chan)
 298 {
 299         return lib_ring_buffer_channel_is_disabled(chan);
 300 }
 301
 302 static
 303 int lttng_flush_buffer(struct lttng_ust_lib_ring_buffer_channel *chan,
 304                 struct lttng_ust_shm_handle *handle)
 305 {
 306         struct lttng_ust_lib_ring_buffer *buf;
 307         int shm_fd, wait_fd, wakeup_fd;
 308         uint64_t memory_map_size;
 309
 310         buf = channel_get_ring_buffer(&client_config, chan,
 311                         0, handle, &shm_fd, &wait_fd, &wakeup_fd,
 312                         &memory_map_size);
 313         lib_ring_buffer_switch(&client_config, buf,
 314                         SWITCH_ACTIVE, handle);
 315         return 0;
 316 }
 317
 318 static struct lttng_transport lttng_relay_transport = {
 319         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 320         .ops = {
 321                 .struct_size = sizeof(struct lttng_ust_channel_ops),
 322
 323                 .priv = __LTTNG_COMPOUND_LITERAL(struct lttng_ust_channel_ops_private, {
 324                         .pub = &lttng_relay_transport.ops,
 325                         .channel_create = _channel_create,
 326                         .channel_destroy = lttng_channel_destroy,
 327                         .packet_avail_size = lttng_packet_avail_size,
 328                         .is_finalized = lttng_is_finalized,
 329                         .is_disabled = lttng_is_disabled,
 330                         .flush_buffer = lttng_flush_buffer,
 331                 }),
 332                 .event_reserve = lttng_event_reserve,
 333                 .event_commit = lttng_event_commit,
 334                 .event_write = lttng_event_write,
 335         },
 336         .client_config = &client_config,
 337 };
 338
 339 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 340 {
 341         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 342                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 343         lttng_transport_register(&lttng_relay_transport);
 344 }
 345
 346 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 347 {
 348         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 349                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 350         lttng_transport_unregister(&lttng_relay_transport);
 351 }