lttng-ring-buffer-metadata-client.h

   1 /*
   2  * lttng-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 <linux/module.h>
  12 #include <linux/types.h>
  13 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  14 #include "lttng-events.h"
  15 #include "lttng-tracer.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  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 lib_ring_buffer_config client_config;
  36
  37 static inline
  38 u64 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 lib_ring_buffer_config *config,
  45                                  struct channel *chan, size_t offset,
  46                                  size_t *pre_header_padding,
  47                                  struct lib_ring_buffer_ctx *ctx)
  48 {
  49         return 0;
  50 }
  51
  52 #include "wrapper/ringbuffer/api.h"
  53
  54 static u64 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 lib_ring_buffer_config *config,
  61                                  struct channel *chan, size_t offset,
  62                                  size_t *pre_header_padding,
  63                                  struct 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 lib_ring_buffer *buf, u64 tsc,
  81                                 unsigned int subbuf_idx)
  82 {
  83         struct channel *chan = buf->backend.chan;
  84         struct metadata_packet_header *header =
  85                 (struct metadata_packet_header *)
  86                         lib_ring_buffer_offset_address(&buf->backend,
  87                                 subbuf_idx * chan->backend.subbuf_size);
  88         struct lttng_channel *lttng_chan = channel_get_private(chan);
  89         struct lttng_session *session = lttng_chan->session;
  90
  91         header->magic = TSDL_MAGIC_NUMBER;
  92         memcpy(header->uuid, session->uuid.b, 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         header->major = CTF_SPEC_MAJOR;
 100         header->minor = CTF_SPEC_MINOR;
 101 }
 102
 103 /*
 104  * offset is assumed to never be 0 here : never deliver a completely empty
 105  * subbuffer. data_size is between 1 and subbuf_size.
 106  */
 107 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 108                               unsigned int subbuf_idx, unsigned long data_size)
 109 {
 110         struct channel *chan = buf->backend.chan;
 111         struct metadata_packet_header *header =
 112                 (struct metadata_packet_header *)
 113                         lib_ring_buffer_offset_address(&buf->backend,
 114                                 subbuf_idx * chan->backend.subbuf_size);
 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         /*
 120          * We do not care about the records lost count, because the metadata
 121          * channel waits and retry.
 122          */
 123         (void) 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 lib_ring_buffer *buf, void *priv,
 130                                 int cpu, const char *name)
 131 {
 132         return 0;
 133 }
 134
 135 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 136 {
 137 }
 138
 139 static const struct lib_ring_buffer_config client_config = {
 140         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 141         .cb.record_header_size = client_record_header_size,
 142         .cb.subbuffer_header_size = client_packet_header_size,
 143         .cb.buffer_begin = client_buffer_begin,
 144         .cb.buffer_end = client_buffer_end,
 145         .cb.buffer_create = client_buffer_create,
 146         .cb.buffer_finalize = client_buffer_finalize,
 147
 148         .tsc_bits = 0,
 149         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 150         .sync = RING_BUFFER_SYNC_GLOBAL,
 151         .mode = RING_BUFFER_MODE_TEMPLATE,
 152         .backend = RING_BUFFER_PAGE,
 153         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 154         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 155         .ipi = RING_BUFFER_IPI_BARRIER,
 156         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 157 };
 158
 159 static
 160 struct channel *_channel_create(const char *name,
 161                                 struct lttng_channel *lttng_chan, void *buf_addr,
 162                                 size_t subbuf_size, size_t num_subbuf,
 163                                 unsigned int switch_timer_interval,
 164                                 unsigned int read_timer_interval)
 165 {
 166         return channel_create(&client_config, name, lttng_chan, buf_addr,
 167                               subbuf_size, num_subbuf, switch_timer_interval,
 168                               read_timer_interval);
 169 }
 170
 171 static
 172 void lttng_channel_destroy(struct channel *chan)
 173 {
 174         channel_destroy(chan);
 175 }
 176
 177 static
 178 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 179 {
 180         struct lib_ring_buffer *buf;
 181
 182         buf = channel_get_ring_buffer(&client_config, chan, 0);
 183         if (!lib_ring_buffer_open_read(buf))
 184                 return buf;
 185         return NULL;
 186 }
 187
 188 static
 189 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 190 {
 191         struct lib_ring_buffer *buf;
 192         int cpu;
 193
 194         for_each_channel_cpu(cpu, chan) {
 195                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 196                 if (!atomic_long_read(&buf->active_readers))
 197                         return 1;
 198         }
 199         return 0;
 200 }
 201
 202 static
 203 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 204 {
 205         lib_ring_buffer_release_read(buf);
 206 }
 207
 208 static
 209 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 210 {
 211         return lib_ring_buffer_reserve(&client_config, ctx);
 212 }
 213
 214 static
 215 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 216 {
 217         lib_ring_buffer_commit(&client_config, ctx);
 218 }
 219
 220 static
 221 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 222                      size_t len)
 223 {
 224         lib_ring_buffer_write(&client_config, ctx, src, len);
 225 }
 226
 227 static
 228 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 229                                const void __user *src, size_t len)
 230 {
 231         lib_ring_buffer_copy_from_user(&client_config, ctx, src, len);
 232 }
 233
 234 static
 235 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 236                 int c, size_t len)
 237 {
 238         lib_ring_buffer_memset(&client_config, ctx, c, len);
 239 }
 240
 241 static
 242 size_t lttng_packet_avail_size(struct channel *chan)
 243
 244 {
 245         unsigned long o_begin;
 246         struct lib_ring_buffer *buf;
 247
 248         buf = chan->backend.buf;        /* Only for global buffer ! */
 249         o_begin = v_read(&client_config, &buf->offset);
 250         if (subbuf_offset(o_begin, chan) != 0) {
 251                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 252         } else {
 253                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 254                         - sizeof(struct metadata_packet_header);
 255         }
 256 }
 257
 258 static
 259 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 260 {
 261         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 262                                         chan, cpu);
 263         return &buf->write_wait;
 264 }
 265
 266 static
 267 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 268 {
 269         return &chan->hp_wait;
 270 }
 271
 272 static
 273 int lttng_is_finalized(struct channel *chan)
 274 {
 275         return lib_ring_buffer_channel_is_finalized(chan);
 276 }
 277
 278 static
 279 int lttng_is_disabled(struct channel *chan)
 280 {
 281         return lib_ring_buffer_channel_is_disabled(chan);
 282 }
 283
 284 static struct lttng_transport lttng_relay_transport = {
 285         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 286         .owner = THIS_MODULE,
 287         .ops = {
 288                 .channel_create = _channel_create,
 289                 .channel_destroy = lttng_channel_destroy,
 290                 .buffer_read_open = lttng_buffer_read_open,
 291                 .buffer_has_read_closed_stream =
 292                         lttng_buffer_has_read_closed_stream,
 293                 .buffer_read_close = lttng_buffer_read_close,
 294                 .event_reserve = lttng_event_reserve,
 295                 .event_commit = lttng_event_commit,
 296                 .event_write_from_user = lttng_event_write_from_user,
 297                 .event_memset = lttng_event_memset,
 298                 .event_write = lttng_event_write,
 299                 .packet_avail_size = lttng_packet_avail_size,
 300                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 301                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 302                 .is_finalized = lttng_is_finalized,
 303                 .is_disabled = lttng_is_disabled,
 304         },
 305 };
 306
 307 static int __init lttng_ring_buffer_client_init(void)
 308 {
 309         /*
 310          * This vmalloc sync all also takes care of the lib ring buffer
 311          * vmalloc'd module pages when it is built as a module into LTTng.
 312          */
 313         wrapper_vmalloc_sync_all();
 314         lttng_transport_register(&lttng_relay_transport);
 315         return 0;
 316 }
 317
 318 module_init(lttng_ring_buffer_client_init);
 319
 320 static void __exit lttng_ring_buffer_client_exit(void)
 321 {
 322         lttng_transport_unregister(&lttng_relay_transport);
 323 }
 324
 325 module_exit(lttng_ring_buffer_client_exit);
 326
 327 MODULE_LICENSE("GPL and additional rights");
 328 MODULE_AUTHOR("Mathieu Desnoyers");
 329 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 330                    " client");