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 #include <lttng/ust-events.h>
  12 #include "ust-bitfield.h"
  13 #include "ust-compat.h"
  14 #include "lttng-tracer.h"
  15 #include "../libringbuffer/frontend_types.h"
  16
  17 struct metadata_packet_header {
  18         uint32_t magic;                 /* 0x75D11D57 */
  19         uint8_t  uuid[LTTNG_UST_UUID_LEN]; /* 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  major;                 /* CTF spec major version number */
  27         uint8_t  minor;                 /* CTF spec minor version number */
  28         uint8_t  header_end[0];
  29 };
  30
  31 struct metadata_record_header {
  32         uint8_t header_end[0];          /* End of header */
  33 };
  34
  35 static const struct lttng_ust_lib_ring_buffer_config client_config;
  36
  37 static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
  38 {
  39         return 0;
  40 }
  41
  42 static inline
  43 size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  44                                  struct channel *chan, size_t offset,
  45                                  size_t *pre_header_padding,
  46                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  47                                  void *client_ctx)
  48 {
  49         return 0;
  50 }
  51
  52 #include "../libringbuffer/api.h"
  53 #include "lttng-rb-clients.h"
  54
  55 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
  56 {
  57         return 0;
  58 }
  59
  60 static
  61 size_t client_record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
  62                                  struct channel *chan, size_t offset,
  63                                  size_t *pre_header_padding,
  64                                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  65                                  void *client_ctx)
  66 {
  67         return 0;
  68 }
  69
  70 /**
  71  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  72  *
  73  * Return header size without padding after the structure. Don't use packed
  74  * structure because gcc generates inefficient code on some architectures
  75  * (powerpc, mips..)
  76  */
  77 static size_t client_packet_header_size(void)
  78 {
  79         return offsetof(struct metadata_packet_header, header_end);
  80 }
  81
  82 static void client_buffer_begin(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
  83                                 unsigned int subbuf_idx,
  84                                 struct lttng_ust_shm_handle *handle)
  85 {
  86         struct channel *chan = shmp(handle, buf->backend.chan);
  87         struct metadata_packet_header *header =
  88                 (struct metadata_packet_header *)
  89                         lib_ring_buffer_offset_address(&buf->backend,
  90                                 subbuf_idx * chan->backend.subbuf_size,
  91                                 handle);
  92         struct lttng_channel *lttng_chan = channel_get_private(chan);
  93
  94         assert(header);
  95         if (!header)
  96                 return;
  97         header->magic = TSDL_MAGIC_NUMBER;
  98         memcpy(header->uuid, lttng_chan->uuid, sizeof(lttng_chan->uuid));
  99         header->checksum = 0;           /* 0 if unused */
 100         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
 101         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
 102         header->compression_scheme = 0; /* 0 if unused */
 103         header->encryption_scheme = 0;  /* 0 if unused */
 104         header->checksum_scheme = 0;    /* 0 if unused */
 105         header->major = CTF_SPEC_MAJOR;
 106         header->minor = CTF_SPEC_MINOR;
 107 }
 108
 109 /*
 110  * offset is assumed to never be 0 here : never deliver a completely empty
 111  * subbuffer. data_size is between 1 and subbuf_size.
 112  */
 113 static void client_buffer_end(struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
 114                               unsigned int subbuf_idx, unsigned long data_size,
 115                               struct lttng_ust_shm_handle *handle)
 116 {
 117         struct channel *chan = shmp(handle, buf->backend.chan);
 118         struct metadata_packet_header *header =
 119                 (struct metadata_packet_header *)
 120                         lib_ring_buffer_offset_address(&buf->backend,
 121                                 subbuf_idx * chan->backend.subbuf_size,
 122                                 handle);
 123         unsigned long records_lost = 0;
 124
 125         assert(header);
 126         if (!header)
 127                 return;
 128         header->content_size = data_size * CHAR_BIT;            /* in bits */
 129         header->packet_size = LTTNG_UST_PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 130         /*
 131          * We do not care about the records lost count, because the metadata
 132          * channel waits and retry.
 133          */
 134         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 135         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 136         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 137         WARN_ON_ONCE(records_lost != 0);
 138 }
 139
 140 static int client_buffer_create(struct lttng_ust_lib_ring_buffer *buf, void *priv,
 141                                 int cpu, const char *name,
 142                                 struct lttng_ust_shm_handle *handle)
 143 {
 144         return 0;
 145 }
 146
 147 static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 148                                    void *priv, int cpu,
 149                                    struct lttng_ust_shm_handle *handle)
 150 {
 151 }
 152
 153 static const
 154 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 155         .parent = {
 156                 .ring_buffer_clock_read = client_ring_buffer_clock_read,
 157                 .record_header_size = client_record_header_size,
 158                 .subbuffer_header_size = client_packet_header_size,
 159                 .buffer_begin = client_buffer_begin,
 160                 .buffer_end = client_buffer_end,
 161                 .buffer_create = client_buffer_create,
 162                 .buffer_finalize = client_buffer_finalize,
 163         },
 164 };
 165
 166 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 167         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 168         .cb.record_header_size = client_record_header_size,
 169         .cb.subbuffer_header_size = client_packet_header_size,
 170         .cb.buffer_begin = client_buffer_begin,
 171         .cb.buffer_end = client_buffer_end,
 172         .cb.buffer_create = client_buffer_create,
 173         .cb.buffer_finalize = client_buffer_finalize,
 174
 175         .tsc_bits = 0,
 176         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 177         .sync = RING_BUFFER_SYNC_GLOBAL,
 178         .mode = RING_BUFFER_MODE_TEMPLATE,
 179         .backend = RING_BUFFER_PAGE,
 180         .output = RING_BUFFER_MMAP,
 181         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 182         .ipi = RING_BUFFER_NO_IPI_BARRIER,
 183         .wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 184         .client_type = LTTNG_CLIENT_TYPE,
 185
 186          .cb_ptr = &client_cb.parent,
 187 };
 188
 189 static
 190 struct lttng_channel *_channel_create(const char *name,
 191                                 void *buf_addr,
 192                                 size_t subbuf_size, size_t num_subbuf,
 193                                 unsigned int switch_timer_interval,
 194                                 unsigned int read_timer_interval,
 195                                 unsigned char *uuid,
 196                                 uint32_t chan_id,
 197                                 const int *stream_fds, int nr_stream_fds,
 198                                 int64_t blocking_timeout)
 199 {
 200         struct lttng_channel chan_priv_init;
 201         struct lttng_ust_shm_handle *handle;
 202         struct lttng_channel *lttng_chan;
 203         void *priv;
 204
 205         memset(&chan_priv_init, 0, sizeof(chan_priv_init));
 206         memcpy(chan_priv_init.uuid, uuid, LTTNG_UST_UUID_LEN);
 207         chan_priv_init.id = chan_id;
 208         handle = channel_create(&client_config, name,
 209                         &priv, __alignof__(struct lttng_channel),
 210                         sizeof(struct lttng_channel),
 211                         &chan_priv_init,
 212                         buf_addr, subbuf_size, num_subbuf,
 213                         switch_timer_interval, read_timer_interval,
 214                         stream_fds, nr_stream_fds, blocking_timeout);
 215         if (!handle)
 216                 return NULL;
 217         lttng_chan = priv;
 218         lttng_chan->handle = handle;
 219         lttng_chan->chan = shmp(handle, handle->chan);
 220         return lttng_chan;
 221 }
 222
 223 static
 224 void lttng_channel_destroy(struct lttng_channel *chan)
 225 {
 226         channel_destroy(chan->chan, chan->handle, 1);
 227 }
 228
 229 static
 230 int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx, uint32_t event_id)
 231 {
 232         int ret;
 233
 234         ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
 235         if (ret)
 236                 return ret;
 237         if (caa_likely(ctx->ctx_len
 238                         >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
 239                 if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
 240                                 &ctx->backend_pages))
 241                         return -EPERM;
 242         }
 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 channel *chan, struct lttng_ust_shm_handle *handle)
 261 {
 262         unsigned long o_begin;
 263         struct lttng_ust_lib_ring_buffer *buf;
 264
 265         buf = shmp(handle, chan->backend.buf[0].shmp);  /* Only for global buffer ! */
 266         o_begin = v_read(&client_config, &buf->offset);
 267         if (subbuf_offset(o_begin, chan) != 0) {
 268                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 269         } else {
 270                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 271                         - sizeof(struct metadata_packet_header);
 272         }
 273 }
 274
 275 #if 0
 276 static
 277 wait_queue_head_t *lttng_get_reader_wait_queue(struct channel *chan)
 278 {
 279         return &chan->read_wait;
 280 }
 281
 282 static
 283 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 284 {
 285         return &chan->hp_wait;
 286 }
 287 #endif //0
 288
 289 static
 290 int lttng_is_finalized(struct channel *chan)
 291 {
 292         return lib_ring_buffer_channel_is_finalized(chan);
 293 }
 294
 295 static
 296 int lttng_is_disabled(struct channel *chan)
 297 {
 298         return lib_ring_buffer_channel_is_disabled(chan);
 299 }
 300
 301 static
 302 int lttng_flush_buffer(struct channel *chan, struct lttng_ust_shm_handle *handle)
 303 {
 304         struct lttng_ust_lib_ring_buffer *buf;
 305         int shm_fd, wait_fd, wakeup_fd;
 306         uint64_t memory_map_size;
 307
 308         buf = channel_get_ring_buffer(&client_config, chan,
 309                         0, handle, &shm_fd, &wait_fd, &wakeup_fd,
 310                         &memory_map_size);
 311         lib_ring_buffer_switch(&client_config, buf,
 312                         SWITCH_ACTIVE, handle);
 313         return 0;
 314 }
 315
 316 static struct lttng_transport lttng_relay_transport = {
 317         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap",
 318         .ops = {
 319                 .channel_create = _channel_create,
 320                 .channel_destroy = lttng_channel_destroy,
 321                 .event_reserve = lttng_event_reserve,
 322                 .event_commit = lttng_event_commit,
 323                 .event_write = lttng_event_write,
 324                 .packet_avail_size = lttng_packet_avail_size,
 325                 //.get_reader_wait_queue = lttng_get_reader_wait_queue,
 326                 //.get_hp_wait_queue = lttng_get_hp_wait_queue,
 327                 .is_finalized = lttng_is_finalized,
 328                 .is_disabled = lttng_is_disabled,
 329                 .flush_buffer = lttng_flush_buffer,
 330         },
 331         .client_config = &client_config,
 332 };
 333
 334 void RING_BUFFER_MODE_TEMPLATE_INIT(void)
 335 {
 336         DBG("LTT : ltt ring buffer client \"%s\" init\n",
 337                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 338         lttng_transport_register(&lttng_relay_transport);
 339 }
 340
 341 void RING_BUFFER_MODE_TEMPLATE_EXIT(void)
 342 {
 343         DBG("LTT : ltt ring buffer client \"%s\" exit\n",
 344                 "relay-" RING_BUFFER_MODE_TEMPLATE_STRING "-mmap");
 345         lttng_transport_unregister(&lttng_relay_transport);
 346 }