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/uuid.h>
  26
  27 #include "lttng-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[LTTNG_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         /* The id of the parent session */
 136         uint64_t tracing_id;
 137         uid_t tracing_uid;
 138 };
 139
 140 struct ust_registry_channel {
 141         uint64_t key;
 142         uint64_t consumer_key;
 143         /* Id set when replying to a register channel. */
 144         uint32_t chan_id;
 145         enum ustctl_channel_header header_type;
 146
 147         /*
 148          * Flag for this channel if the metadata was dumped once during
 149          * registration. 0 means no, 1 yes.
 150          */
 151         unsigned int metadata_dumped;
 152         /* Indicates if this channel registry has already been registered. */
 153         unsigned int register_done;
 154
 155         /*
 156          * Hash table containing events sent by the UST tracer. MUST be accessed
 157          * with a RCU read side lock acquired.
 158          */
 159         struct lttng_ht *ht;
 160         /* Next event ID available for a newly registered event. */
 161         uint32_t next_event_id;
 162         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
 163         uint32_t used_event_id;
 164         /*
 165          * Context fields of the registry. Context are per channel. Allocated by a
 166          * register channel notification from the UST tracer.
 167          */
 168         size_t nr_ctx_fields;
 169         struct ustctl_field *ctx_fields;
 170         struct lttng_ht_node_u64 node;
 171         /* For delayed reclaim */
 172         struct rcu_head rcu_head;
 173 };
 174
 175 /*
 176  * Event registered from a UST tracer sent to the session daemon. This is
 177  * indexed and matched by <event_name/signature>.
 178  */
 179 struct ust_registry_event {
 180         int id;
 181         /* Both objd are set by the tracer. */
 182         int session_objd;
 183         int channel_objd;
 184         /* Name of the event returned by the tracer. */
 185         char name[LTTNG_UST_SYM_NAME_LEN];
 186         char *signature;
 187         int loglevel_value;
 188         size_t nr_fields;
 189         struct ustctl_field *fields;
 190         char *model_emf_uri;
 191         /*
 192          * Flag for this channel if the metadata was dumped once during
 193          * registration. 0 means no, 1 yes.
 194          */
 195         unsigned int metadata_dumped;
 196         /*
 197          * Node in the ust-registry hash table. The event name is used to
 198          * initialize the node and the event_name/signature for the match function.
 199          */
 200         struct lttng_ht_node_u64 node;
 201 };
 202
 203 struct ust_registry_enum {
 204         char name[LTTNG_UST_SYM_NAME_LEN];
 205         struct ustctl_enum_entry *entries;
 206         size_t nr_entries;
 207         uint64_t id;    /* enum id in session */
 208         /* Enumeration node in session hash table. */
 209         struct lttng_ht_node_str node;
 210         /* For delayed reclaim. */
 211         struct rcu_head rcu_head;
 212 };
 213
 214 /*
 215  * Validate that the id has reached the maximum allowed or not.
 216  *
 217  * Return 0 if NOT else 1.
 218  */
 219 static inline int ust_registry_is_max_id(uint32_t id)
 220 {
 221         return (id == UINT32_MAX) ? 1 : 0;
 222 }
 223
 224 /*
 225  * Return next available event id and increment the used counter. The
 226  * ust_registry_is_max_id function MUST be called before in order to validate
 227  * if the maximum number of IDs have been reached. If not, it is safe to call
 228  * this function.
 229  *
 230  * Return a unique channel ID. If max is reached, the used_event_id counter is
 231  * returned.
 232  */
 233 static inline uint32_t ust_registry_get_next_event_id(
 234                 struct ust_registry_channel *r)
 235 {
 236         if (ust_registry_is_max_id(r->used_event_id)) {
 237                 return r->used_event_id;
 238         }
 239
 240         r->used_event_id++;
 241         return r->next_event_id++;
 242 }
 243
 244 /*
 245  * Return next available channel id and increment the used counter. The
 246  * ust_registry_is_max_id function MUST be called before in order to validate
 247  * if the maximum number of IDs have been reached. If not, it is safe to call
 248  * this function.
 249  *
 250  * Return a unique channel ID. If max is reached, the used_channel_id counter
 251  * is returned.
 252  */
 253 static inline uint32_t ust_registry_get_next_chan_id(
 254                 struct ust_registry_session *r)
 255 {
 256         if (ust_registry_is_max_id(r->used_channel_id)) {
 257                 return r->used_channel_id;
 258         }
 259
 260         r->used_channel_id++;
 261         return r->next_channel_id++;
 262 }
 263
 264 /*
 265  * Return registry event count. This is read atomically.
 266  */
 267 static inline uint32_t ust_registry_get_event_count(
 268                 struct ust_registry_channel *r)
 269 {
 270         return (uint32_t) uatomic_read(&r->used_event_id);
 271 }
 272
 273 #ifdef HAVE_LIBLTTNG_UST_CTL
 274
 275 void ust_registry_channel_destroy(struct ust_registry_session *session,
 276                 struct ust_registry_channel *chan);
 277 struct ust_registry_channel *ust_registry_channel_find(
 278                 struct ust_registry_session *session, uint64_t key);
 279 int ust_registry_channel_add(struct ust_registry_session *session,
 280                 uint64_t key);
 281 void ust_registry_channel_del_free(struct ust_registry_session *session,
 282                 uint64_t key, bool notif);
 283
 284 int ust_registry_session_init(struct ust_registry_session **sessionp,
 285                 struct ust_app *app,
 286                 uint32_t bits_per_long,
 287                 uint32_t uint8_t_alignment,
 288                 uint32_t uint16_t_alignment,
 289                 uint32_t uint32_t_alignment,
 290                 uint32_t uint64_t_alignment,
 291                 uint32_t long_alignment,
 292                 int byte_order,
 293                 uint32_t major,
 294                 uint32_t minor,
 295                 const char *root_shm_path,
 296                 const char *shm_path,
 297                 uid_t euid,
 298                 gid_t egid,
 299                 uint64_t tracing_id,
 300                 uid_t tracing_uid);
 301 void ust_registry_session_destroy(struct ust_registry_session *session);
 302
 303 int ust_registry_create_event(struct ust_registry_session *session,
 304                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 305                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 306                 int loglevel_value, char *model_emf_uri, int buffer_type,
 307                 uint32_t *event_id_p, struct ust_app *app);
 308 struct ust_registry_event *ust_registry_find_event(
 309                 struct ust_registry_channel *chan, char *name, char *sig);
 310 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 311                 struct ust_registry_event *event);
 312
 313 /* app can be NULL for registry shared across applications. */
 314 int ust_metadata_session_statedump(struct ust_registry_session *session,
 315                 struct ust_app *app, uint32_t major, uint32_t minor);
 316 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 317                 struct ust_registry_channel *chan);
 318 int ust_metadata_event_statedump(struct ust_registry_session *session,
 319                 struct ust_registry_channel *chan,
 320                 struct ust_registry_event *event);
 321 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 322                 int session_objd, char *name,
 323                 struct ustctl_enum_entry *entries, size_t nr_entries,
 324                 uint64_t *enum_id);
 325 struct ust_registry_enum *
 326         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 327                 const char *name, uint64_t id);
 328
 329 #else /* HAVE_LIBLTTNG_UST_CTL */
 330
 331 static inline
 332 void ust_registry_channel_destroy(struct ust_registry_session *session,
 333                 struct ust_registry_channel *chan)
 334 {}
 335 static inline
 336 struct ust_registry_channel *ust_registry_channel_find(
 337                 struct ust_registry_session *session, uint64_t key)
 338 {
 339         return NULL;
 340 }
 341 static inline
 342 int ust_registry_channel_add(struct ust_registry_session *session,
 343                 uint64_t key)
 344 {
 345         return 0;
 346 }
 347 static inline
 348 void ust_registry_channel_del_free(struct ust_registry_session *session,
 349                 uint64_t key, bool notif)
 350 {}
 351 static inline
 352 int ust_registry_session_init(struct ust_registry_session **sessionp,
 353                 struct ust_app *app,
 354                 uint32_t bits_per_long,
 355                 uint32_t uint8_t_alignment,
 356                 uint32_t uint16_t_alignment,
 357                 uint32_t uint32_t_alignment,
 358                 uint32_t uint64_t_alignment,
 359                 uint32_t long_alignment,
 360                 int byte_order,
 361                 uint32_t major,
 362                 uint32_t minor,
 363                 const char *root_shm_path,
 364                 const char *shm_path,
 365                 uid_t euid,
 366                 gid_t egid,
 367                 uint64_t tracing_id,
 368                 uid_t tracing_uid)
 369 {
 370         return 0;
 371 }
 372 static inline
 373 void ust_registry_session_destroy(struct ust_registry_session *session)
 374 {}
 375 static inline
 376 int ust_registry_create_event(struct ust_registry_session *session,
 377                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 378                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 379                 int loglevel_value, char *model_emf_uri, int buffer_type,
 380                 uint32_t *event_id_p)
 381 {
 382         return 0;
 383 }
 384 static inline
 385 struct ust_registry_event *ust_registry_find_event(
 386                 struct ust_registry_channel *chan, char *name, char *sig)
 387 {
 388         return NULL;
 389 }
 390 static inline
 391 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 392                 struct ust_registry_event *event)
 393 {}
 394
 395 /* The app object can be NULL for registry shared across applications. */
 396 static inline
 397 int ust_metadata_session_statedump(struct ust_registry_session *session,
 398                 struct ust_app *app, uint32_t major, uint32_t minor)
 399 {
 400         return 0;
 401 }
 402 static inline
 403 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 404                 struct ust_registry_channel *chan)
 405 {
 406         return 0;
 407 }
 408 static inline
 409 int ust_metadata_event_statedump(struct ust_registry_session *session,
 410                 struct ust_registry_channel *chan,
 411                 struct ust_registry_event *event)
 412 {
 413         return 0;
 414 }
 415 static inline
 416 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 417                 int session_objd, char *name,
 418                 struct ustctl_enum_entry *entries, size_t nr_entries,
 419                 uint64_t *enum_id)
 420 {
 421         return 0;
 422 }
 423 static inline
 424 struct ust_registry_enum *
 425         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 426                 const char *name, uint64_t id)
 427 {
 428         return NULL;
 429 }
 430
 431 #endif /* HAVE_LIBLTTNG_UST_CTL */
 432
 433 #endif /* LTTNG_UST_REGISTRY_H */