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 <linux/module.h>
  24 #include <linux/types.h>
  25 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  26 #include "lttng-events.h"
  27 #include "lttng-tracer.h"
  28
  29 struct metadata_packet_header {
  30         uint32_t magic;                 /* 0x75D11D57 */
  31         uint8_t  uuid[16];              /* 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 lib_ring_buffer_config client_config;
  48
  49 static inline
  50 u64 lib_ring_buffer_clock_read(struct channel *chan)
  51 {
  52         return 0;
  53 }
  54
  55 static inline
  56 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  57                                  struct channel *chan, size_t offset,
  58                                  size_t *pre_header_padding,
  59                                  struct lib_ring_buffer_ctx *ctx)
  60 {
  61         return 0;
  62 }
  63
  64 #include "wrapper/ringbuffer/api.h"
  65
  66 static u64 client_ring_buffer_clock_read(struct channel *chan)
  67 {
  68         return 0;
  69 }
  70
  71 static
  72 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  73                                  struct channel *chan, size_t offset,
  74                                  size_t *pre_header_padding,
  75                                  struct lib_ring_buffer_ctx *ctx)
  76 {
  77         return 0;
  78 }
  79
  80 /**
  81  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  82  *
  83  * Return header size without padding after the structure. Don't use packed
  84  * structure because gcc generates inefficient code on some architectures
  85  * (powerpc, mips..)
  86  */
  87 static size_t client_packet_header_size(void)
  88 {
  89         return offsetof(struct metadata_packet_header, header_end);
  90 }
  91
  92 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  93                                 unsigned int subbuf_idx)
  94 {
  95         struct channel *chan = 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         struct lttng_channel *lttng_chan = channel_get_private(chan);
 101         struct lttng_session *session = lttng_chan->session;
 102
 103         header->magic = TSDL_MAGIC_NUMBER;
 104         memcpy(header->uuid, session->uuid.b, sizeof(session->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 lib_ring_buffer *buf, u64 tsc,
 120                               unsigned int subbuf_idx, unsigned long data_size)
 121 {
 122         struct channel *chan = buf->backend.chan;
 123         struct metadata_packet_header *header =
 124                 (struct metadata_packet_header *)
 125                         lib_ring_buffer_offset_address(&buf->backend,
 126                                 subbuf_idx * chan->backend.subbuf_size);
 127         unsigned long records_lost = 0;
 128
 129         header->content_size = data_size * CHAR_BIT;            /* in bits */
 130         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 131         /*
 132          * We do not care about the records lost count, because the metadata
 133          * channel waits and retry.
 134          */
 135         (void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
 136         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 137         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 138         WARN_ON_ONCE(records_lost != 0);
 139 }
 140
 141 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 142                                 int cpu, const char *name)
 143 {
 144         return 0;
 145 }
 146
 147 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 148 {
 149 }
 150
 151 static const struct lib_ring_buffer_config client_config = {
 152         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 153         .cb.record_header_size = client_record_header_size,
 154         .cb.subbuffer_header_size = client_packet_header_size,
 155         .cb.buffer_begin = client_buffer_begin,
 156         .cb.buffer_end = client_buffer_end,
 157         .cb.buffer_create = client_buffer_create,
 158         .cb.buffer_finalize = client_buffer_finalize,
 159
 160         .tsc_bits = 0,
 161         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 162         .sync = RING_BUFFER_SYNC_GLOBAL,
 163         .mode = RING_BUFFER_MODE_TEMPLATE,
 164         .backend = RING_BUFFER_PAGE,
 165         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 166         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 167         .ipi = RING_BUFFER_IPI_BARRIER,
 168         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 169 };
 170
 171 static
 172 struct channel *_channel_create(const char *name,
 173                                 struct lttng_channel *lttng_chan, void *buf_addr,
 174                                 size_t subbuf_size, size_t num_subbuf,
 175                                 unsigned int switch_timer_interval,
 176                                 unsigned int read_timer_interval)
 177 {
 178         return channel_create(&client_config, name, lttng_chan, buf_addr,
 179                               subbuf_size, num_subbuf, switch_timer_interval,
 180                               read_timer_interval);
 181 }
 182
 183 static
 184 void lttng_channel_destroy(struct channel *chan)
 185 {
 186         channel_destroy(chan);
 187 }
 188
 189 static
 190 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 191 {
 192         struct lib_ring_buffer *buf;
 193
 194         buf = channel_get_ring_buffer(&client_config, chan, 0);
 195         if (!lib_ring_buffer_open_read(buf))
 196                 return buf;
 197         return NULL;
 198 }
 199
 200 static
 201 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 202 {
 203         struct lib_ring_buffer *buf;
 204         int cpu;
 205
 206         for_each_channel_cpu(cpu, chan) {
 207                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 208                 if (!atomic_long_read(&buf->active_readers))
 209                         return 1;
 210         }
 211         return 0;
 212 }
 213
 214 static
 215 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 216 {
 217         lib_ring_buffer_release_read(buf);
 218 }
 219
 220 static
 221 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 222 {
 223         return lib_ring_buffer_reserve(&client_config, ctx);
 224 }
 225
 226 static
 227 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 228 {
 229         lib_ring_buffer_commit(&client_config, ctx);
 230 }
 231
 232 static
 233 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 234                      size_t len)
 235 {
 236         lib_ring_buffer_write(&client_config, ctx, src, len);
 237 }
 238
 239 static
 240 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 241                                const void __user *src, size_t len)
 242 {
 243         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 244 }
 245
 246 static
 247 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 248                 int c, size_t len)
 249 {
 250         lib_ring_buffer_memset(&client_config, ctx, c, len);
 251 }
 252
 253 static
 254 size_t lttng_packet_avail_size(struct channel *chan)
 255
 256 {
 257         unsigned long o_begin;
 258         struct lib_ring_buffer *buf;
 259
 260         buf = chan->backend.buf;        /* Only for global buffer ! */
 261         o_begin = v_read(&client_config, &buf->offset);
 262         if (subbuf_offset(o_begin, chan) != 0) {
 263                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 264         } else {
 265                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 266                         - sizeof(struct metadata_packet_header);
 267         }
 268 }
 269
 270 static
 271 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 272 {
 273         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 274                                         chan, cpu);
 275         return &buf->write_wait;
 276 }
 277
 278 static
 279 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 280 {
 281         return &chan->hp_wait;
 282 }
 283
 284 static
 285 int lttng_is_finalized(struct channel *chan)
 286 {
 287         return lib_ring_buffer_channel_is_finalized(chan);
 288 }
 289
 290 static
 291 int lttng_is_disabled(struct channel *chan)
 292 {
 293         return lib_ring_buffer_channel_is_disabled(chan);
 294 }
 295
 296 static struct lttng_transport lttng_relay_transport = {
 297         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 298         .owner = THIS_MODULE,
 299         .ops = {
 300                 .channel_create = _channel_create,
 301                 .channel_destroy = lttng_channel_destroy,
 302                 .buffer_read_open = lttng_buffer_read_open,
 303                 .buffer_has_read_closed_stream =
 304                         lttng_buffer_has_read_closed_stream,
 305                 .buffer_read_close = lttng_buffer_read_close,
 306                 .event_reserve = lttng_event_reserve,
 307                 .event_commit = lttng_event_commit,
 308                 .event_write_from_user = lttng_event_write_from_user,
 309                 .event_memset = lttng_event_memset,
 310                 .event_write = lttng_event_write,
 311                 .packet_avail_size = lttng_packet_avail_size,
 312                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 313                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 314                 .is_finalized = lttng_is_finalized,
 315                 .is_disabled = lttng_is_disabled,
 316         },
 317 };
 318
 319 static int __init lttng_ring_buffer_client_init(void)
 320 {
 321         /*
 322          * This vmalloc sync all also takes care of the lib ring buffer
 323          * vmalloc'd module pages when it is built as a module into LTTng.
 324          */
 325         wrapper_vmalloc_sync_all();
 326         lttng_transport_register(&lttng_relay_transport);
 327         return 0;
 328 }
 329
 330 module_init(lttng_ring_buffer_client_init);
 331
 332 static void __exit lttng_ring_buffer_client_exit(void)
 333 {
 334         lttng_transport_unregister(&lttng_relay_transport);
 335 }
 336
 337 module_exit(lttng_ring_buffer_client_exit);
 338
 339 MODULE_LICENSE("GPL and additional rights");
 340 MODULE_AUTHOR("Mathieu Desnoyers");
 341 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 342                    " client");