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         /* Universal unique identifier used by the tracer. */
  49         unsigned char uuid[UUID_LEN];
  50
  51         /* session ABI description */
  52
  53         /* Size of long, in bits */
  54         unsigned int bits_per_long;
  55         /* Alignment, in bits */
  56         unsigned int uint8_t_alignment,
  57                 uint16_t_alignment,
  58                 uint32_t_alignment,
  59                 uint64_t_alignment,
  60                 long_alignment;
  61         /* endianness */
  62         int byte_order; /* BIG_ENDIAN or LITTLE_ENDIAN */
  63
  64         /* Generated metadata. */
  65         char *metadata;         /* NOT null-terminated ! Use memcpy. */
  66         size_t metadata_len, metadata_alloc_len;
  67         /* Length of bytes sent to the consumer. */
  68         size_t metadata_len_sent;
  69
  70         char root_shm_path[PATH_MAX];
  71         char shm_path[PATH_MAX];
  72         char metadata_path[PATH_MAX];
  73         int metadata_fd;        /* file-backed metadata FD */
  74
  75         /*
  76          * Hash table containing channels sent by the UST tracer. MUST
  77          * be accessed with a RCU read side lock acquired.
  78          */
  79         struct lttng_ht *channels;
  80         /*
  81          * Unique key to identify the metadata on the consumer side.
  82          */
  83         uint64_t metadata_key;
  84         /*
  85          * Indicates if the metadata is closed on the consumer side. This is to
  86          * avoid double close of metadata when an application unregisters AND
  87          * deletes its sessions.
  88          */
  89         unsigned int metadata_closed;
  90 };
  91
  92 struct ust_registry_channel {
  93         uint64_t key;
  94         /* Id set when replying to a register channel. */
  95         uint32_t chan_id;
  96         enum ustctl_channel_header header_type;
  97
  98         /*
  99          * Flag for this channel if the metadata was dumped once during
 100          * registration. 0 means no, 1 yes.
 101          */
 102         unsigned int metadata_dumped;
 103         /* Indicates if this channel registry has already been registered. */
 104         unsigned int register_done;
 105
 106         /*
 107          * Hash table containing events sent by the UST tracer. MUST be accessed
 108          * with a RCU read side lock acquired.
 109          */
 110         struct lttng_ht *ht;
 111         /* Next event ID available for a newly registered event. */
 112         uint32_t next_event_id;
 113         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
 114         uint32_t used_event_id;
 115         /*
 116          * Context fields of the registry. Context are per channel. Allocated by a
 117          * register channel notification from the UST tracer.
 118          */
 119         size_t nr_ctx_fields;
 120         struct ustctl_field *ctx_fields;
 121         struct lttng_ht_node_u64 node;
 122         /* For delayed reclaim */
 123         struct rcu_head rcu_head;
 124 };
 125
 126 /*
 127  * Event registered from a UST tracer sent to the session daemon. This is
 128  * indexed and matched by <event_name/signature>.
 129  */
 130 struct ust_registry_event {
 131         int id;
 132         /* Both objd are set by the tracer. */
 133         int session_objd;
 134         int channel_objd;
 135         /* Name of the event returned by the tracer. */
 136         char name[LTTNG_UST_SYM_NAME_LEN];
 137         char *signature;
 138         int loglevel;
 139         size_t nr_fields;
 140         struct ustctl_field *fields;
 141         char *model_emf_uri;
 142         /*
 143          * Flag for this channel if the metadata was dumped once during
 144          * registration. 0 means no, 1 yes.
 145          */
 146         unsigned int metadata_dumped;
 147         /*
 148          * Node in the ust-registry hash table. The event name is used to
 149          * initialize the node and the event_name/signature for the match function.
 150          */
 151         struct lttng_ht_node_u64 node;
 152 };
 153
 154 /*
 155  * Validate that the id has reached the maximum allowed or not.
 156  *
 157  * Return 0 if NOT else 1.
 158  */
 159 static inline int ust_registry_is_max_id(uint32_t id)
 160 {
 161         return (id == UINT32_MAX) ? 1 : 0;
 162 }
 163
 164 /*
 165  * Return next available event id and increment the used counter. The
 166  * ust_registry_is_max_id function MUST be called before in order to validate
 167  * if the maximum number of IDs have been reached. If not, it is safe to call
 168  * this function.
 169  *
 170  * Return a unique channel ID. If max is reached, the used_event_id counter is
 171  * returned.
 172  */
 173 static inline uint32_t ust_registry_get_next_event_id(
 174                 struct ust_registry_channel *r)
 175 {
 176         if (ust_registry_is_max_id(r->used_event_id)) {
 177                 return r->used_event_id;
 178         }
 179
 180         r->used_event_id++;
 181         return r->next_event_id++;
 182 }
 183
 184 /*
 185  * Return next available channel id and increment the used counter. The
 186  * ust_registry_is_max_id function MUST be called before in order to validate
 187  * if the maximum number of IDs have been reached. If not, it is safe to call
 188  * this function.
 189  *
 190  * Return a unique channel ID. If max is reached, the used_channel_id counter
 191  * is returned.
 192  */
 193 static inline uint32_t ust_registry_get_next_chan_id(
 194                 struct ust_registry_session *r)
 195 {
 196         if (ust_registry_is_max_id(r->used_channel_id)) {
 197                 return r->used_channel_id;
 198         }
 199
 200         r->used_channel_id++;
 201         return r->next_channel_id++;
 202 }
 203
 204 /*
 205  * Return registry event count. This is read atomically.
 206  */
 207 static inline uint32_t ust_registry_get_event_count(
 208                 struct ust_registry_channel *r)
 209 {
 210         return (uint32_t) uatomic_read(&r->used_event_id);
 211 }
 212
 213 #ifdef HAVE_LIBLTTNG_UST_CTL
 214
 215 void ust_registry_channel_destroy(struct ust_registry_session *session,
 216                 struct ust_registry_channel *chan);
 217 struct ust_registry_channel *ust_registry_channel_find(
 218                 struct ust_registry_session *session, uint64_t key);
 219 int ust_registry_channel_add(struct ust_registry_session *session,
 220                 uint64_t key);
 221 void ust_registry_channel_del_free(struct ust_registry_session *session,
 222                 uint64_t key);
 223
 224 int ust_registry_session_init(struct ust_registry_session **sessionp,
 225                 struct ust_app *app,
 226                 uint32_t bits_per_long,
 227                 uint32_t uint8_t_alignment,
 228                 uint32_t uint16_t_alignment,
 229                 uint32_t uint32_t_alignment,
 230                 uint32_t uint64_t_alignment,
 231                 uint32_t long_alignment,
 232                 int byte_order,
 233                 uint32_t major,
 234                 uint32_t minor,
 235                 const char *root_shm_path,
 236                 const char *shm_path,
 237                 uid_t euid,
 238                 gid_t egid);
 239 void ust_registry_session_destroy(struct ust_registry_session *session);
 240
 241 int ust_registry_create_event(struct ust_registry_session *session,
 242                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 243                 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
 244                 char *model_emf_uri, int buffer_type, uint32_t *event_id_p,
 245                 struct ust_app *app);
 246 struct ust_registry_event *ust_registry_find_event(
 247                 struct ust_registry_channel *chan, char *name, char *sig);
 248 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 249                 struct ust_registry_event *event);
 250
 251 /* app can be NULL for registry shared across applications. */
 252 int ust_metadata_session_statedump(struct ust_registry_session *session,
 253                 struct ust_app *app, uint32_t major, uint32_t minor);
 254 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 255                 struct ust_registry_channel *chan);
 256 int ust_metadata_event_statedump(struct ust_registry_session *session,
 257                 struct ust_registry_channel *chan,
 258                 struct ust_registry_event *event);
 259
 260 #else /* HAVE_LIBLTTNG_UST_CTL */
 261
 262 static inline
 263 void ust_registry_channel_destroy(struct ust_registry_session *session,
 264                 struct ust_registry_channel *chan)
 265 {}
 266 static inline
 267 struct ust_registry_channel *ust_registry_channel_find(
 268                 struct ust_registry_session *session, uint64_t key)
 269 {
 270         return NULL;
 271 }
 272 static inline
 273 int ust_registry_channel_add(struct ust_registry_session *session,
 274                 uint64_t key)
 275 {
 276         return 0;
 277 }
 278 static inline
 279 void ust_registry_channel_del_free(struct ust_registry_session *session,
 280                 uint64_t key)
 281 {}
 282 static inline
 283 int ust_registry_session_init(struct ust_registry_session **sessionp,
 284                 struct ust_app *app,
 285                 uint32_t bits_per_long,
 286                 uint32_t uint8_t_alignment,
 287                 uint32_t uint16_t_alignment,
 288                 uint32_t uint32_t_alignment,
 289                 uint32_t uint64_t_alignment,
 290                 uint32_t long_alignment,
 291                 int byte_order)
 292 {
 293         return 0;
 294 }
 295 static inline
 296 void ust_registry_session_destroy(struct ust_registry_session *session)
 297 {}
 298 static inline
 299 int ust_registry_create_event(struct ust_registry_session *session,
 300                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 301                 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
 302                 char *model_emf_uri, int buffer_type, uint32_t *event_id_p)
 303 {
 304         return 0;
 305 }
 306 static inline
 307 struct ust_registry_event *ust_registry_find_event(
 308                 struct ust_registry_channel *chan, char *name, char *sig)
 309 {
 310         return NULL;
 311 }
 312 static inline
 313 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 314                 struct ust_registry_event *event)
 315 {}
 316
 317 /* The app object can be NULL for registry shared across applications. */
 318 static inline
 319 int ust_metadata_session_statedump(struct ust_registry_session *session,
 320                 struct ust_app *app)
 321 {
 322         return 0;
 323 }
 324 static inline
 325 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 326                 struct ust_registry_channel *chan)
 327 {
 328         return 0;
 329 }
 330 static inline
 331 int ust_metadata_event_statedump(struct ust_registry_session *session,
 332                 struct ust_registry_channel *chan,
 333                 struct ust_registry_event *event)
 334 {
 335         return 0;
 336 }
 337
 338 #endif /* HAVE_LIBLTTNG_UST_CTL */
 339
 340 #endif /* LTTNG_UST_REGISTRY_H */