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         char root_shm_path[PATH_MAX];
  75         char shm_path[PATH_MAX];
  76         char metadata_path[PATH_MAX];
  77         int metadata_fd;        /* file-backed metadata FD */
  78
  79         /*
  80          * Hash table containing channels sent by the UST tracer. MUST
  81          * be accessed with a RCU read side lock acquired.
  82          */
  83         struct lttng_ht *channels;
  84         /*
  85          * Unique key to identify the metadata on the consumer side.
  86          */
  87         uint64_t metadata_key;
  88         /*
  89          * Indicates if the metadata is closed on the consumer side. This is to
  90          * avoid double close of metadata when an application unregisters AND
  91          * deletes its sessions.
  92          */
  93         unsigned int metadata_closed;
  94
  95         /* User and group owning the session. */
  96         uid_t uid;
  97         gid_t gid;
  98
  99         /* Enumerations table. */
 100         struct lttng_ht *enums;
 101
 102         /*
 103          * Copy of the tracer version when the first app is registered.
 104          * It is used if we need to regenerate the metadata.
 105          */
 106         uint32_t major;
 107         uint32_t minor;
 108 };
 109
 110 struct ust_registry_channel {
 111         uint64_t key;
 112         /* Id set when replying to a register channel. */
 113         uint32_t chan_id;
 114         enum ustctl_channel_header header_type;
 115
 116         /*
 117          * Flag for this channel if the metadata was dumped once during
 118          * registration. 0 means no, 1 yes.
 119          */
 120         unsigned int metadata_dumped;
 121         /* Indicates if this channel registry has already been registered. */
 122         unsigned int register_done;
 123
 124         /*
 125          * Hash table containing events sent by the UST tracer. MUST be accessed
 126          * with a RCU read side lock acquired.
 127          */
 128         struct lttng_ht *ht;
 129         /* Next event ID available for a newly registered event. */
 130         uint32_t next_event_id;
 131         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
 132         uint32_t used_event_id;
 133         /*
 134          * Context fields of the registry. Context are per channel. Allocated by a
 135          * register channel notification from the UST tracer.
 136          */
 137         size_t nr_ctx_fields;
 138         struct ustctl_field *ctx_fields;
 139         struct lttng_ht_node_u64 node;
 140         /* For delayed reclaim */
 141         struct rcu_head rcu_head;
 142 };
 143
 144 /*
 145  * Event registered from a UST tracer sent to the session daemon. This is
 146  * indexed and matched by <event_name/signature>.
 147  */
 148 struct ust_registry_event {
 149         int id;
 150         /* Both objd are set by the tracer. */
 151         int session_objd;
 152         int channel_objd;
 153         /* Name of the event returned by the tracer. */
 154         char name[LTTNG_UST_SYM_NAME_LEN];
 155         char *signature;
 156         int loglevel_value;
 157         size_t nr_fields;
 158         struct ustctl_field *fields;
 159         char *model_emf_uri;
 160         /*
 161          * Flag for this channel if the metadata was dumped once during
 162          * registration. 0 means no, 1 yes.
 163          */
 164         unsigned int metadata_dumped;
 165         /*
 166          * Node in the ust-registry hash table. The event name is used to
 167          * initialize the node and the event_name/signature for the match function.
 168          */
 169         struct lttng_ht_node_u64 node;
 170 };
 171
 172 struct ust_registry_enum {
 173         char name[LTTNG_UST_SYM_NAME_LEN];
 174         struct ustctl_enum_entry *entries;
 175         size_t nr_entries;
 176         uint64_t id;    /* enum id in session */
 177         /* Enumeration node in session hash table. */
 178         struct lttng_ht_node_str node;
 179         /* For delayed reclaim. */
 180         struct rcu_head rcu_head;
 181 };
 182
 183 /*
 184  * Validate that the id has reached the maximum allowed or not.
 185  *
 186  * Return 0 if NOT else 1.
 187  */
 188 static inline int ust_registry_is_max_id(uint32_t id)
 189 {
 190         return (id == UINT32_MAX) ? 1 : 0;
 191 }
 192
 193 /*
 194  * Return next available event id and increment the used counter. The
 195  * ust_registry_is_max_id function MUST be called before in order to validate
 196  * if the maximum number of IDs have been reached. If not, it is safe to call
 197  * this function.
 198  *
 199  * Return a unique channel ID. If max is reached, the used_event_id counter is
 200  * returned.
 201  */
 202 static inline uint32_t ust_registry_get_next_event_id(
 203                 struct ust_registry_channel *r)
 204 {
 205         if (ust_registry_is_max_id(r->used_event_id)) {
 206                 return r->used_event_id;
 207         }
 208
 209         r->used_event_id++;
 210         return r->next_event_id++;
 211 }
 212
 213 /*
 214  * Return next available channel id and increment the used counter. The
 215  * ust_registry_is_max_id function MUST be called before in order to validate
 216  * if the maximum number of IDs have been reached. If not, it is safe to call
 217  * this function.
 218  *
 219  * Return a unique channel ID. If max is reached, the used_channel_id counter
 220  * is returned.
 221  */
 222 static inline uint32_t ust_registry_get_next_chan_id(
 223                 struct ust_registry_session *r)
 224 {
 225         if (ust_registry_is_max_id(r->used_channel_id)) {
 226                 return r->used_channel_id;
 227         }
 228
 229         r->used_channel_id++;
 230         return r->next_channel_id++;
 231 }
 232
 233 /*
 234  * Return registry event count. This is read atomically.
 235  */
 236 static inline uint32_t ust_registry_get_event_count(
 237                 struct ust_registry_channel *r)
 238 {
 239         return (uint32_t) uatomic_read(&r->used_event_id);
 240 }
 241
 242 #ifdef HAVE_LIBLTTNG_UST_CTL
 243
 244 void ust_registry_channel_destroy(struct ust_registry_session *session,
 245                 struct ust_registry_channel *chan);
 246 struct ust_registry_channel *ust_registry_channel_find(
 247                 struct ust_registry_session *session, uint64_t key);
 248 int ust_registry_channel_add(struct ust_registry_session *session,
 249                 uint64_t key);
 250 void ust_registry_channel_del_free(struct ust_registry_session *session,
 251                 uint64_t key);
 252
 253 int ust_registry_session_init(struct ust_registry_session **sessionp,
 254                 struct ust_app *app,
 255                 uint32_t bits_per_long,
 256                 uint32_t uint8_t_alignment,
 257                 uint32_t uint16_t_alignment,
 258                 uint32_t uint32_t_alignment,
 259                 uint32_t uint64_t_alignment,
 260                 uint32_t long_alignment,
 261                 int byte_order,
 262                 uint32_t major,
 263                 uint32_t minor,
 264                 const char *root_shm_path,
 265                 const char *shm_path,
 266                 uid_t euid,
 267                 gid_t egid);
 268 void ust_registry_session_destroy(struct ust_registry_session *session);
 269
 270 int ust_registry_create_event(struct ust_registry_session *session,
 271                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 272                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 273                 int loglevel_value, char *model_emf_uri, int buffer_type,
 274                 uint32_t *event_id_p, struct ust_app *app);
 275 struct ust_registry_event *ust_registry_find_event(
 276                 struct ust_registry_channel *chan, char *name, char *sig);
 277 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 278                 struct ust_registry_event *event);
 279
 280 /* app can be NULL for registry shared across applications. */
 281 int ust_metadata_session_statedump(struct ust_registry_session *session,
 282                 struct ust_app *app, uint32_t major, uint32_t minor);
 283 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 284                 struct ust_registry_channel *chan);
 285 int ust_metadata_event_statedump(struct ust_registry_session *session,
 286                 struct ust_registry_channel *chan,
 287                 struct ust_registry_event *event);
 288 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 289                 int session_objd, char *name,
 290                 struct ustctl_enum_entry *entries, size_t nr_entries,
 291                 uint64_t *enum_id);
 292 struct ust_registry_enum *
 293         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 294                 const char *name, uint64_t id);
 295
 296 #else /* HAVE_LIBLTTNG_UST_CTL */
 297
 298 static inline
 299 void ust_registry_channel_destroy(struct ust_registry_session *session,
 300                 struct ust_registry_channel *chan)
 301 {}
 302 static inline
 303 struct ust_registry_channel *ust_registry_channel_find(
 304                 struct ust_registry_session *session, uint64_t key)
 305 {
 306         return NULL;
 307 }
 308 static inline
 309 int ust_registry_channel_add(struct ust_registry_session *session,
 310                 uint64_t key)
 311 {
 312         return 0;
 313 }
 314 static inline
 315 void ust_registry_channel_del_free(struct ust_registry_session *session,
 316                 uint64_t key)
 317 {}
 318 static inline
 319 int ust_registry_session_init(struct ust_registry_session **sessionp,
 320                 struct ust_app *app,
 321                 uint32_t bits_per_long,
 322                 uint32_t uint8_t_alignment,
 323                 uint32_t uint16_t_alignment,
 324                 uint32_t uint32_t_alignment,
 325                 uint32_t uint64_t_alignment,
 326                 uint32_t long_alignment,
 327                 int byte_order)
 328 {
 329         return 0;
 330 }
 331 static inline
 332 void ust_registry_session_destroy(struct ust_registry_session *session)
 333 {}
 334 static inline
 335 int ust_registry_create_event(struct ust_registry_session *session,
 336                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 337                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 338                 int loglevel_value, char *model_emf_uri, int buffer_type,
 339                 uint32_t *event_id_p)
 340 {
 341         return 0;
 342 }
 343 static inline
 344 struct ust_registry_event *ust_registry_find_event(
 345                 struct ust_registry_channel *chan, char *name, char *sig)
 346 {
 347         return NULL;
 348 }
 349 static inline
 350 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 351                 struct ust_registry_event *event)
 352 {}
 353
 354 /* The app object can be NULL for registry shared across applications. */
 355 static inline
 356 int ust_metadata_session_statedump(struct ust_registry_session *session,
 357                 struct ust_app *app)
 358 {
 359         return 0;
 360 }
 361 static inline
 362 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 363                 struct ust_registry_channel *chan)
 364 {
 365         return 0;
 366 }
 367 static inline
 368 int ust_metadata_event_statedump(struct ust_registry_session *session,
 369                 struct ust_registry_channel *chan,
 370                 struct ust_registry_event *event)
 371 {
 372         return 0;
 373 }
 374 static inline
 375 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 376                 int session_objd, char *name,
 377                 struct ustctl_enum_entry *entries, size_t nr_entries,
 378                 uint64_t *enum_id)
 379 {
 380         return 0;
 381 }
 382 static inline
 383 struct ust_registry_enum *
 384         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 385                 const char *name, uint64_t id)
 386 {
 387         return NULL;
 388 }
 389
 390 #endif /* HAVE_LIBLTTNG_UST_CTL */
 391
 392 #endif /* LTTNG_UST_REGISTRY_H */