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

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef LTTNG_UST_REGISTRY_H
  19 #define LTTNG_UST_REGISTRY_H
  20
  21 #include <pthread.h>
  22 #include <stdint.h>
  23
  24 #include <common/hashtable/hashtable.h>
  25 #include <common/compat/uuid.h>
  26
  27 #include "ust-ctl.h"
  28
  29 #define CTF_SPEC_MAJOR  1
  30 #define CTF_SPEC_MINOR  8
  31
  32 struct ust_app;
  33
  34 struct ust_registry_session {
  35         /*
  36          * With multiple writers and readers, use this lock to access
  37          * the registry. Can nest within the ust app session lock.
  38          * Also acts as a registry serialization lock. Used by registry
  39          * readers to serialize the registry information sent from the
  40          * sessiond to the consumerd.
  41          * The consumer socket lock nests within this lock.
  42          */
  43         pthread_mutex_t lock;
  44         /* Next channel ID available for a newly registered channel. */
  45         uint32_t next_channel_id;
  46         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
  47         uint32_t used_channel_id;
  48         /* Next enumeration ID available. */
  49         uint64_t next_enum_id;
  50         /* Universal unique identifier used by the tracer. */
  51         unsigned char uuid[UUID_LEN];
  52
  53         /* session ABI description */
  54
  55         /* Size of long, in bits */
  56         unsigned int bits_per_long;
  57         /* Alignment, in bits */
  58         unsigned int uint8_t_alignment,
  59                 uint16_t_alignment,
  60                 uint32_t_alignment,
  61                 uint64_t_alignment,
  62                 long_alignment;
  63         /* endianness */
  64         int byte_order; /* BIG_ENDIAN or LITTLE_ENDIAN */
  65
  66         /* Generated metadata. */
  67         char *metadata;         /* NOT null-terminated ! Use memcpy. */
  68         size_t metadata_len, metadata_alloc_len;
  69         /* Length of bytes sent to the consumer. */
  70         size_t metadata_len_sent;
  71         /* Current version of the metadata. */
  72         uint64_t metadata_version;
  73
  74         /*
  75          * Those fields are only used when a session is created with
  76          * the --shm-path option. In this case, the metadata is output
  77          * twice: once to the consumer, as ususal, but a second time
  78          * also in the shm path directly. This is done so that a copy
  79          * of the metadata that is as fresh as possible is available
  80          * on the event of a crash.
  81          *
  82          * root_shm_path contains the shm-path provided by the user, along with
  83          * the session's name and timestamp:
  84          *   e.g. /tmp/my_shm/my_session-20180612-135822
  85          *
  86          * shm_path contains the full path of the memory buffers:
  87          *   e.g. /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit
  88          *
  89          * metadata_path contains the full path to the metadata file that
  90          * is kept for the "crash buffer" extraction:
  91          *  e.g. /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit/metadata
  92          *
  93          * Note that this is not the trace's final metadata file. It is
  94          * only meant to be used to read the contents of the ring buffers
  95          * in the event of a crash.
  96          *
  97          * metadata_fd is a file descriptor that points to the file at
  98          * 'metadata_path'.
  99          */
 100         char root_shm_path[PATH_MAX];
 101         char shm_path[PATH_MAX];
 102         char metadata_path[PATH_MAX];
 103         int metadata_fd;        /* file-backed metadata FD */
 104
 105         /*
 106          * Hash table containing channels sent by the UST tracer. MUST
 107          * be accessed with a RCU read side lock acquired.
 108          */
 109         struct lttng_ht *channels;
 110         /*
 111          * Unique key to identify the metadata on the consumer side.
 112          */
 113         uint64_t metadata_key;
 114         /*
 115          * Indicates if the metadata is closed on the consumer side. This is to
 116          * avoid double close of metadata when an application unregisters AND
 117          * deletes its sessions.
 118          */
 119         unsigned int metadata_closed;
 120
 121         /* User and group owning the session. */
 122         uid_t uid;
 123         gid_t gid;
 124
 125         /* Enumerations table. */
 126         struct lttng_ht *enums;
 127
 128         /*
 129          * Copy of the tracer version when the first app is registered.
 130          * It is used if we need to regenerate the metadata.
 131          */
 132         uint32_t major;
 133         uint32_t minor;
 134 };
 135
 136 struct ust_registry_channel {
 137         uint64_t key;
 138         uint64_t consumer_key;
 139         /* Id set when replying to a register channel. */
 140         uint32_t chan_id;
 141         enum ustctl_channel_header header_type;
 142
 143         /*
 144          * Flag for this channel if the metadata was dumped once during
 145          * registration. 0 means no, 1 yes.
 146          */
 147         unsigned int metadata_dumped;
 148         /* Indicates if this channel registry has already been registered. */
 149         unsigned int register_done;
 150
 151         /*
 152          * Hash table containing events sent by the UST tracer. MUST be accessed
 153          * with a RCU read side lock acquired.
 154          */
 155         struct lttng_ht *ht;
 156         /* Next event ID available for a newly registered event. */
 157         uint32_t next_event_id;
 158         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
 159         uint32_t used_event_id;
 160         /*
 161          * Context fields of the registry. Context are per channel. Allocated by a
 162          * register channel notification from the UST tracer.
 163          */
 164         size_t nr_ctx_fields;
 165         struct ustctl_field *ctx_fields;
 166         struct lttng_ht_node_u64 node;
 167         /* For delayed reclaim */
 168         struct rcu_head rcu_head;
 169 };
 170
 171 /*
 172  * Event registered from a UST tracer sent to the session daemon. This is
 173  * indexed and matched by <event_name/signature>.
 174  */
 175 struct ust_registry_event {
 176         int id;
 177         /* Both objd are set by the tracer. */
 178         int session_objd;
 179         int channel_objd;
 180         /* Name of the event returned by the tracer. */
 181         char name[LTTNG_UST_SYM_NAME_LEN];
 182         char *signature;
 183         int loglevel_value;
 184         size_t nr_fields;
 185         struct ustctl_field *fields;
 186         char *model_emf_uri;
 187         /*
 188          * Flag for this channel if the metadata was dumped once during
 189          * registration. 0 means no, 1 yes.
 190          */
 191         unsigned int metadata_dumped;
 192         /*
 193          * Node in the ust-registry hash table. The event name is used to
 194          * initialize the node and the event_name/signature for the match function.
 195          */
 196         struct lttng_ht_node_u64 node;
 197 };
 198
 199 struct ust_registry_enum {
 200         char name[LTTNG_UST_SYM_NAME_LEN];
 201         struct ustctl_enum_entry *entries;
 202         size_t nr_entries;
 203         uint64_t id;    /* enum id in session */
 204         /* Enumeration node in session hash table. */
 205         struct lttng_ht_node_str node;
 206         /* For delayed reclaim. */
 207         struct rcu_head rcu_head;
 208 };
 209
 210 /*
 211  * Validate that the id has reached the maximum allowed or not.
 212  *
 213  * Return 0 if NOT else 1.
 214  */
 215 static inline int ust_registry_is_max_id(uint32_t id)
 216 {
 217         return (id == UINT32_MAX) ? 1 : 0;
 218 }
 219
 220 /*
 221  * Return next available event id and increment the used counter. The
 222  * ust_registry_is_max_id function MUST be called before in order to validate
 223  * if the maximum number of IDs have been reached. If not, it is safe to call
 224  * this function.
 225  *
 226  * Return a unique channel ID. If max is reached, the used_event_id counter is
 227  * returned.
 228  */
 229 static inline uint32_t ust_registry_get_next_event_id(
 230                 struct ust_registry_channel *r)
 231 {
 232         if (ust_registry_is_max_id(r->used_event_id)) {
 233                 return r->used_event_id;
 234         }
 235
 236         r->used_event_id++;
 237         return r->next_event_id++;
 238 }
 239
 240 /*
 241  * Return next available channel id and increment the used counter. The
 242  * ust_registry_is_max_id function MUST be called before in order to validate
 243  * if the maximum number of IDs have been reached. If not, it is safe to call
 244  * this function.
 245  *
 246  * Return a unique channel ID. If max is reached, the used_channel_id counter
 247  * is returned.
 248  */
 249 static inline uint32_t ust_registry_get_next_chan_id(
 250                 struct ust_registry_session *r)
 251 {
 252         if (ust_registry_is_max_id(r->used_channel_id)) {
 253                 return r->used_channel_id;
 254         }
 255
 256         r->used_channel_id++;
 257         return r->next_channel_id++;
 258 }
 259
 260 /*
 261  * Return registry event count. This is read atomically.
 262  */
 263 static inline uint32_t ust_registry_get_event_count(
 264                 struct ust_registry_channel *r)
 265 {
 266         return (uint32_t) uatomic_read(&r->used_event_id);
 267 }
 268
 269 #ifdef HAVE_LIBLTTNG_UST_CTL
 270
 271 void ust_registry_channel_destroy(struct ust_registry_session *session,
 272                 struct ust_registry_channel *chan);
 273 struct ust_registry_channel *ust_registry_channel_find(
 274                 struct ust_registry_session *session, uint64_t key);
 275 int ust_registry_channel_add(struct ust_registry_session *session,
 276                 uint64_t key);
 277 void ust_registry_channel_del_free(struct ust_registry_session *session,
 278                 uint64_t key, bool notif);
 279
 280 int ust_registry_session_init(struct ust_registry_session **sessionp,
 281                 struct ust_app *app,
 282                 uint32_t bits_per_long,
 283                 uint32_t uint8_t_alignment,
 284                 uint32_t uint16_t_alignment,
 285                 uint32_t uint32_t_alignment,
 286                 uint32_t uint64_t_alignment,
 287                 uint32_t long_alignment,
 288                 int byte_order,
 289                 uint32_t major,
 290                 uint32_t minor,
 291                 const char *root_shm_path,
 292                 const char *shm_path,
 293                 uid_t euid,
 294                 gid_t egid);
 295 void ust_registry_session_destroy(struct ust_registry_session *session);
 296
 297 int ust_registry_create_event(struct ust_registry_session *session,
 298                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 299                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 300                 int loglevel_value, char *model_emf_uri, int buffer_type,
 301                 uint32_t *event_id_p, struct ust_app *app);
 302 struct ust_registry_event *ust_registry_find_event(
 303                 struct ust_registry_channel *chan, char *name, char *sig);
 304 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 305                 struct ust_registry_event *event);
 306
 307 /* app can be NULL for registry shared across applications. */
 308 int ust_metadata_session_statedump(struct ust_registry_session *session,
 309                 struct ust_app *app, uint32_t major, uint32_t minor);
 310 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 311                 struct ust_registry_channel *chan);
 312 int ust_metadata_event_statedump(struct ust_registry_session *session,
 313                 struct ust_registry_channel *chan,
 314                 struct ust_registry_event *event);
 315 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 316                 int session_objd, char *name,
 317                 struct ustctl_enum_entry *entries, size_t nr_entries,
 318                 uint64_t *enum_id);
 319 struct ust_registry_enum *
 320         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 321                 const char *name, uint64_t id);
 322
 323 #else /* HAVE_LIBLTTNG_UST_CTL */
 324
 325 static inline
 326 void ust_registry_channel_destroy(struct ust_registry_session *session,
 327                 struct ust_registry_channel *chan)
 328 {}
 329 static inline
 330 struct ust_registry_channel *ust_registry_channel_find(
 331                 struct ust_registry_session *session, uint64_t key)
 332 {
 333         return NULL;
 334 }
 335 static inline
 336 int ust_registry_channel_add(struct ust_registry_session *session,
 337                 uint64_t key)
 338 {
 339         return 0;
 340 }
 341 static inline
 342 void ust_registry_channel_del_free(struct ust_registry_session *session,
 343                 uint64_t key, bool notif)
 344 {}
 345 static inline
 346 int ust_registry_session_init(struct ust_registry_session **sessionp,
 347                 struct ust_app *app,
 348                 uint32_t bits_per_long,
 349                 uint32_t uint8_t_alignment,
 350                 uint32_t uint16_t_alignment,
 351                 uint32_t uint32_t_alignment,
 352                 uint32_t uint64_t_alignment,
 353                 uint32_t long_alignment,
 354                 int byte_order)
 355 {
 356         return 0;
 357 }
 358 static inline
 359 void ust_registry_session_destroy(struct ust_registry_session *session)
 360 {}
 361 static inline
 362 int ust_registry_create_event(struct ust_registry_session *session,
 363                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 364                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 365                 int loglevel_value, char *model_emf_uri, int buffer_type,
 366                 uint32_t *event_id_p)
 367 {
 368         return 0;
 369 }
 370 static inline
 371 struct ust_registry_event *ust_registry_find_event(
 372                 struct ust_registry_channel *chan, char *name, char *sig)
 373 {
 374         return NULL;
 375 }
 376 static inline
 377 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 378                 struct ust_registry_event *event)
 379 {}
 380
 381 /* The app object can be NULL for registry shared across applications. */
 382 static inline
 383 int ust_metadata_session_statedump(struct ust_registry_session *session,
 384                 struct ust_app *app, uint32_t major, uint32_t minor)
 385 {
 386         return 0;
 387 }
 388 static inline
 389 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 390                 struct ust_registry_channel *chan)
 391 {
 392         return 0;
 393 }
 394 static inline
 395 int ust_metadata_event_statedump(struct ust_registry_session *session,
 396                 struct ust_registry_channel *chan,
 397                 struct ust_registry_event *event)
 398 {
 399         return 0;
 400 }
 401 static inline
 402 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 403                 int session_objd, char *name,
 404                 struct ustctl_enum_entry *entries, size_t nr_entries,
 405                 uint64_t *enum_id)
 406 {
 407         return 0;
 408 }
 409 static inline
 410 struct ust_registry_enum *
 411         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 412                 const char *name, uint64_t id)
 413 {
 414         return NULL;
 415 }
 416
 417 #endif /* HAVE_LIBLTTNG_UST_CTL */
 418
 419 #endif /* LTTNG_UST_REGISTRY_H */