src/bin/lttng-sessiond/ust-registry.h

   1 /*
   2  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_UST_REGISTRY_H
   9 #define LTTNG_UST_REGISTRY_H
  10
  11 #include <pthread.h>
  12 #include <stdint.h>
  13
  14 #include <common/hashtable/hashtable.h>
  15 #include <common/uuid.h>
  16
  17 #include "lttng-ust-ctl.h"
  18
  19 #define CTF_SPEC_MAJOR  1
  20 #define CTF_SPEC_MINOR  8
  21
  22 struct ust_app;
  23
  24 struct ust_registry_session {
  25         /*
  26          * With multiple writers and readers, use this lock to access
  27          * the registry. Can nest within the ust app session lock.
  28          * Also acts as a registry serialization lock. Used by registry
  29          * readers to serialize the registry information sent from the
  30          * sessiond to the consumerd.
  31          * The consumer socket lock nests within this lock.
  32          */
  33         pthread_mutex_t lock;
  34         /* Next channel ID available for a newly registered channel. */
  35         uint32_t next_channel_id;
  36         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
  37         uint32_t used_channel_id;
  38         /* Next enumeration ID available. */
  39         uint64_t next_enum_id;
  40         /* Universal unique identifier used by the tracer. */
  41         unsigned char uuid[LTTNG_UUID_LEN];
  42
  43         /* session ABI description */
  44
  45         /* Size of long, in bits */
  46         unsigned int bits_per_long;
  47         /* Alignment, in bits */
  48         unsigned int uint8_t_alignment,
  49                 uint16_t_alignment,
  50                 uint32_t_alignment,
  51                 uint64_t_alignment,
  52                 long_alignment;
  53         /* endianness */
  54         int byte_order; /* BIG_ENDIAN or LITTLE_ENDIAN */
  55
  56         /* Generated metadata. */
  57         char *metadata;         /* NOT null-terminated ! Use memcpy. */
  58         size_t metadata_len, metadata_alloc_len;
  59         /* Length of bytes sent to the consumer. */
  60         size_t metadata_len_sent;
  61         /* Current version of the metadata. */
  62         uint64_t metadata_version;
  63
  64         /*
  65          * Those fields are only used when a session is created with
  66          * the --shm-path option. In this case, the metadata is output
  67          * twice: once to the consumer, as ususal, but a second time
  68          * also in the shm path directly. This is done so that a copy
  69          * of the metadata that is as fresh as possible is available
  70          * on the event of a crash.
  71          *
  72          * root_shm_path contains the shm-path provided by the user, along with
  73          * the session's name and timestamp:
  74          *   e.g. /tmp/my_shm/my_session-20180612-135822
  75          *
  76          * shm_path contains the full path of the memory buffers:
  77          *   e.g. /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit
  78          *
  79          * metadata_path contains the full path to the metadata file that
  80          * is kept for the "crash buffer" extraction:
  81          *  e.g. /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit/metadata
  82          *
  83          * Note that this is not the trace's final metadata file. It is
  84          * only meant to be used to read the contents of the ring buffers
  85          * in the event of a crash.
  86          *
  87          * metadata_fd is a file descriptor that points to the file at
  88          * 'metadata_path'.
  89          */
  90         char root_shm_path[PATH_MAX];
  91         char shm_path[PATH_MAX];
  92         char metadata_path[PATH_MAX];
  93         int metadata_fd;        /* file-backed metadata FD */
  94
  95         /*
  96          * Hash table containing channels sent by the UST tracer. MUST
  97          * be accessed with a RCU read side lock acquired.
  98          */
  99         struct lttng_ht *channels;
 100         /*
 101          * Unique key to identify the metadata on the consumer side.
 102          */
 103         uint64_t metadata_key;
 104         /*
 105          * Indicates if the metadata is closed on the consumer side. This is to
 106          * avoid double close of metadata when an application unregisters AND
 107          * deletes its sessions.
 108          */
 109         unsigned int metadata_closed;
 110
 111         /* User and group owning the session. */
 112         uid_t uid;
 113         gid_t gid;
 114
 115         /* Enumerations table. */
 116         struct lttng_ht *enums;
 117
 118         /*
 119          * Copy of the tracer version when the first app is registered.
 120          * It is used if we need to regenerate the metadata.
 121          */
 122         uint32_t major;
 123         uint32_t minor;
 124
 125         /* The id of the parent session */
 126         uint64_t tracing_id;
 127         uid_t tracing_uid;
 128 };
 129
 130 struct ust_registry_channel {
 131         uint64_t key;
 132         uint64_t consumer_key;
 133         /* Id set when replying to a register channel. */
 134         uint32_t chan_id;
 135         enum ustctl_channel_header header_type;
 136
 137         /*
 138          * Flag for this channel if the metadata was dumped once during
 139          * registration. 0 means no, 1 yes.
 140          */
 141         unsigned int metadata_dumped;
 142         /* Indicates if this channel registry has already been registered. */
 143         unsigned int register_done;
 144
 145         /*
 146          * Hash table containing events sent by the UST tracer. MUST be accessed
 147          * with a RCU read side lock acquired.
 148          */
 149         struct lttng_ht *ht;
 150         /* Next event ID available for a newly registered event. */
 151         uint32_t next_event_id;
 152         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
 153         uint32_t used_event_id;
 154         /*
 155          * Context fields of the registry. Context are per channel. Allocated by a
 156          * register channel notification from the UST tracer.
 157          */
 158         size_t nr_ctx_fields;
 159         struct ustctl_field *ctx_fields;
 160         struct lttng_ht_node_u64 node;
 161         /* For delayed reclaim */
 162         struct rcu_head rcu_head;
 163 };
 164
 165 /*
 166  * Event registered from a UST tracer sent to the session daemon. This is
 167  * indexed and matched by <event_name/signature>.
 168  */
 169 struct ust_registry_event {
 170         int id;
 171         /* Both objd are set by the tracer. */
 172         int session_objd;
 173         int channel_objd;
 174         /* Name of the event returned by the tracer. */
 175         char name[LTTNG_UST_SYM_NAME_LEN];
 176         char *signature;
 177         int loglevel_value;
 178         size_t nr_fields;
 179         struct ustctl_field *fields;
 180         char *model_emf_uri;
 181         /*
 182          * Flag for this channel if the metadata was dumped once during
 183          * registration. 0 means no, 1 yes.
 184          */
 185         unsigned int metadata_dumped;
 186         /*
 187          * Node in the ust-registry hash table. The event name is used to
 188          * initialize the node and the event_name/signature for the match function.
 189          */
 190         struct lttng_ht_node_u64 node;
 191 };
 192
 193 struct ust_registry_enum {
 194         char name[LTTNG_UST_SYM_NAME_LEN];
 195         struct ustctl_enum_entry *entries;
 196         size_t nr_entries;
 197         uint64_t id;    /* enum id in session */
 198         /* Enumeration node in session hash table. */
 199         struct lttng_ht_node_str node;
 200         /* For delayed reclaim. */
 201         struct rcu_head rcu_head;
 202 };
 203
 204 /*
 205  * Validate that the id has reached the maximum allowed or not.
 206  *
 207  * Return 0 if NOT else 1.
 208  */
 209 static inline int ust_registry_is_max_id(uint32_t id)
 210 {
 211         return (id == UINT32_MAX) ? 1 : 0;
 212 }
 213
 214 /*
 215  * Return next available event id and increment the used counter. The
 216  * ust_registry_is_max_id function MUST be called before in order to validate
 217  * if the maximum number of IDs have been reached. If not, it is safe to call
 218  * this function.
 219  *
 220  * Return a unique channel ID. If max is reached, the used_event_id counter is
 221  * returned.
 222  */
 223 static inline uint32_t ust_registry_get_next_event_id(
 224                 struct ust_registry_channel *r)
 225 {
 226         if (ust_registry_is_max_id(r->used_event_id)) {
 227                 return r->used_event_id;
 228         }
 229
 230         r->used_event_id++;
 231         return r->next_event_id++;
 232 }
 233
 234 /*
 235  * Return next available channel id and increment the used counter. The
 236  * ust_registry_is_max_id function MUST be called before in order to validate
 237  * if the maximum number of IDs have been reached. If not, it is safe to call
 238  * this function.
 239  *
 240  * Return a unique channel ID. If max is reached, the used_channel_id counter
 241  * is returned.
 242  */
 243 static inline uint32_t ust_registry_get_next_chan_id(
 244                 struct ust_registry_session *r)
 245 {
 246         if (ust_registry_is_max_id(r->used_channel_id)) {
 247                 return r->used_channel_id;
 248         }
 249
 250         r->used_channel_id++;
 251         return r->next_channel_id++;
 252 }
 253
 254 /*
 255  * Return registry event count. This is read atomically.
 256  */
 257 static inline uint32_t ust_registry_get_event_count(
 258                 struct ust_registry_channel *r)
 259 {
 260         return (uint32_t) uatomic_read(&r->used_event_id);
 261 }
 262
 263 #ifdef HAVE_LIBLTTNG_UST_CTL
 264
 265 void ust_registry_channel_destroy(struct ust_registry_session *session,
 266                 struct ust_registry_channel *chan);
 267 struct ust_registry_channel *ust_registry_channel_find(
 268                 struct ust_registry_session *session, uint64_t key);
 269 int ust_registry_channel_add(struct ust_registry_session *session,
 270                 uint64_t key);
 271 void ust_registry_channel_del_free(struct ust_registry_session *session,
 272                 uint64_t key, bool notif);
 273
 274 int ust_registry_session_init(struct ust_registry_session **sessionp,
 275                 struct ust_app *app,
 276                 uint32_t bits_per_long,
 277                 uint32_t uint8_t_alignment,
 278                 uint32_t uint16_t_alignment,
 279                 uint32_t uint32_t_alignment,
 280                 uint32_t uint64_t_alignment,
 281                 uint32_t long_alignment,
 282                 int byte_order,
 283                 uint32_t major,
 284                 uint32_t minor,
 285                 const char *root_shm_path,
 286                 const char *shm_path,
 287                 uid_t euid,
 288                 gid_t egid,
 289                 uint64_t tracing_id,
 290                 uid_t tracing_uid);
 291 void ust_registry_session_destroy(struct ust_registry_session *session);
 292
 293 int ust_registry_create_event(struct ust_registry_session *session,
 294                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 295                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 296                 int loglevel_value, char *model_emf_uri, int buffer_type,
 297                 uint32_t *event_id_p, struct ust_app *app);
 298 struct ust_registry_event *ust_registry_find_event(
 299                 struct ust_registry_channel *chan, char *name, char *sig);
 300 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 301                 struct ust_registry_event *event);
 302
 303 /* app can be NULL for registry shared across applications. */
 304 int ust_metadata_session_statedump(struct ust_registry_session *session,
 305                 struct ust_app *app, uint32_t major, uint32_t minor);
 306 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 307                 struct ust_registry_channel *chan);
 308 int ust_metadata_event_statedump(struct ust_registry_session *session,
 309                 struct ust_registry_channel *chan,
 310                 struct ust_registry_event *event);
 311 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 312                 int session_objd, char *name,
 313                 struct ustctl_enum_entry *entries, size_t nr_entries,
 314                 uint64_t *enum_id);
 315 struct ust_registry_enum *
 316         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 317                 const char *name, uint64_t id);
 318
 319 #else /* HAVE_LIBLTTNG_UST_CTL */
 320
 321 static inline
 322 void ust_registry_channel_destroy(struct ust_registry_session *session,
 323                 struct ust_registry_channel *chan)
 324 {}
 325 static inline
 326 struct ust_registry_channel *ust_registry_channel_find(
 327                 struct ust_registry_session *session, uint64_t key)
 328 {
 329         return NULL;
 330 }
 331 static inline
 332 int ust_registry_channel_add(struct ust_registry_session *session,
 333                 uint64_t key)
 334 {
 335         return 0;
 336 }
 337 static inline
 338 void ust_registry_channel_del_free(struct ust_registry_session *session,
 339                 uint64_t key, bool notif)
 340 {}
 341 static inline
 342 int ust_registry_session_init(struct ust_registry_session **sessionp,
 343                 struct ust_app *app,
 344                 uint32_t bits_per_long,
 345                 uint32_t uint8_t_alignment,
 346                 uint32_t uint16_t_alignment,
 347                 uint32_t uint32_t_alignment,
 348                 uint32_t uint64_t_alignment,
 349                 uint32_t long_alignment,
 350                 int byte_order,
 351                 uint32_t major,
 352                 uint32_t minor,
 353                 const char *root_shm_path,
 354                 const char *shm_path,
 355                 uid_t euid,
 356                 gid_t egid,
 357                 uint64_t tracing_id,
 358                 uid_t tracing_uid)
 359 {
 360         return 0;
 361 }
 362 static inline
 363 void ust_registry_session_destroy(struct ust_registry_session *session)
 364 {}
 365 static inline
 366 int ust_registry_create_event(struct ust_registry_session *session,
 367                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 368                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 369                 int loglevel_value, char *model_emf_uri, int buffer_type,
 370                 uint32_t *event_id_p)
 371 {
 372         return 0;
 373 }
 374 static inline
 375 struct ust_registry_event *ust_registry_find_event(
 376                 struct ust_registry_channel *chan, char *name, char *sig)
 377 {
 378         return NULL;
 379 }
 380 static inline
 381 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 382                 struct ust_registry_event *event)
 383 {}
 384
 385 /* The app object can be NULL for registry shared across applications. */
 386 static inline
 387 int ust_metadata_session_statedump(struct ust_registry_session *session,
 388                 struct ust_app *app, uint32_t major, uint32_t minor)
 389 {
 390         return 0;
 391 }
 392 static inline
 393 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 394                 struct ust_registry_channel *chan)
 395 {
 396         return 0;
 397 }
 398 static inline
 399 int ust_metadata_event_statedump(struct ust_registry_session *session,
 400                 struct ust_registry_channel *chan,
 401                 struct ust_registry_event *event)
 402 {
 403         return 0;
 404 }
 405 static inline
 406 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 407                 int session_objd, char *name,
 408                 struct ustctl_enum_entry *entries, size_t nr_entries,
 409                 uint64_t *enum_id)
 410 {
 411         return 0;
 412 }
 413 static inline
 414 struct ust_registry_enum *
 415         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 416                 const char *name, uint64_t id)
 417 {
 418         return NULL;
 419 }
 420
 421 #endif /* HAVE_LIBLTTNG_UST_CTL */
 422
 423 #endif /* LTTNG_UST_REGISTRY_H */