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 #include <lttng/ust-ctl.h>
  24
  25 #include <common/hashtable/hashtable.h>
  26 #include <common/compat/uuid.h>
  27
  28 #define CTF_SPEC_MAJOR  1
  29 #define CTF_SPEC_MINOR  8
  30
  31 struct ust_app;
  32
  33 struct ust_registry_session {
  34         /*
  35          * With multiple writers and readers, use this lock to access
  36          * the registry. Use defined macros above to lock it.
  37          * Can nest within the ust app session lock.
  38          */
  39         pthread_mutex_t lock;
  40         /* Next channel ID available for a newly registered channel. */
  41         uint32_t next_channel_id;
  42         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
  43         uint32_t used_channel_id;
  44         /* Universal unique identifier used by the tracer. */
  45         unsigned char uuid[UUID_LEN];
  46
  47         /* session ABI description */
  48
  49         /* Size of long, in bits */
  50         unsigned int bits_per_long;
  51         /* Alignment, in bits */
  52         unsigned int uint8_t_alignment,
  53                 uint16_t_alignment,
  54                 uint32_t_alignment,
  55                 uint64_t_alignment,
  56                 long_alignment;
  57         /* endianness */
  58         int byte_order; /* BIG_ENDIAN or LITTLE_ENDIAN */
  59
  60         /* Generated metadata. */
  61         char *metadata;         /* NOT null-terminated ! Use memcpy. */
  62         size_t metadata_len, metadata_alloc_len;
  63         /* Length of bytes sent to the consumer. */
  64         size_t metadata_len_sent;
  65 };
  66
  67 struct ust_registry_channel {
  68         /* Id set when replying to a register channel. */
  69         uint32_t chan_id;
  70         enum ustctl_channel_header header_type;
  71
  72         /*
  73          * Hash table containing events sent by the UST tracer. MUST be accessed
  74          * with a RCU read side lock acquired.
  75          */
  76         struct lttng_ht *ht;
  77         /* Next event ID available for a newly registered event. */
  78         uint32_t next_event_id;
  79         /* Once this value reaches UINT32_MAX, no more id can be allocated. */
  80         uint32_t used_event_id;
  81         /*
  82          * Context fields of the registry. Context are per channel. Allocated by a
  83          * register channel notification from the UST tracer.
  84          */
  85         size_t nr_ctx_fields;
  86         struct ustctl_field *ctx_fields;
  87 };
  88
  89 /*
  90  * Event registered from a UST tracer sent to the session daemon. This is
  91  * indexed and matched by <event_name/signature>.
  92  */
  93 struct ust_registry_event {
  94         int id;
  95         /* Both objd are set by the tracer. */
  96         int session_objd;
  97         int channel_objd;
  98         /* Name of the event returned by the tracer. */
  99         char name[LTTNG_UST_SYM_NAME_LEN];
 100         char *signature;
 101         int loglevel;
 102         size_t nr_fields;
 103         struct ustctl_field *fields;
 104         char *model_emf_uri;
 105         /*
 106          * Node in the ust-registry hash table. The event name is used to
 107          * initialize the node and the event_name/signature for the match function.
 108          */
 109         struct lttng_ht_node_str node;
 110 };
 111
 112 /*
 113  * Validate that the id has reached the maximum allowed or not.
 114  *
 115  * Return 0 if NOT else 1.
 116  */
 117 static inline int ust_registry_is_max_id(uint32_t id)
 118 {
 119         return (id == UINT32_MAX) ? 1 : 0;
 120 }
 121
 122 /*
 123  * Return next available event id and increment the used counter. The
 124  * ust_registry_is_max_id function MUST be called before in order to validate
 125  * if the maximum number of IDs have been reached. If not, it is safe to call
 126  * this function.
 127  *
 128  * Return a unique channel ID. If max is reached, the used_event_id counter is
 129  * returned.
 130  */
 131 static inline uint32_t ust_registry_get_next_event_id(
 132                 struct ust_registry_channel *r)
 133 {
 134         if (ust_registry_is_max_id(r->used_event_id)) {
 135                 return r->used_event_id;
 136         }
 137
 138         r->used_event_id++;
 139         return r->next_event_id++;
 140 }
 141
 142 /*
 143  * Return next available channel id and increment the used counter. The
 144  * ust_registry_is_max_id function MUST be called before in order to validate
 145  * if the maximum number of IDs have been reached. If not, it is safe to call
 146  * this function.
 147  *
 148  * Return a unique channel ID. If max is reached, the used_channel_id counter
 149  * is returned.
 150  */
 151 static inline uint32_t ust_registry_get_next_chan_id(
 152                 struct ust_registry_session *r)
 153 {
 154         if (ust_registry_is_max_id(r->used_channel_id)) {
 155                 return r->used_channel_id;
 156         }
 157
 158         r->used_channel_id++;
 159         return r->next_channel_id++;
 160 }
 161
 162 /*
 163  * Return registry event count. This is read atomically.
 164  */
 165 static inline uint32_t ust_registry_get_event_count(
 166                 struct ust_registry_channel *r)
 167 {
 168         return (uint32_t) uatomic_read(&r->used_event_id);
 169 }
 170
 171 void ust_registry_channel_init(struct ust_registry_session *session,
 172                 struct ust_registry_channel *chan);
 173 void ust_registry_channel_destroy(struct ust_registry_session *session,
 174                 struct ust_registry_channel *chan);
 175
 176 int ust_registry_session_init(struct ust_registry_session *session,
 177                 struct ust_app *app,
 178                 uint32_t bits_per_long,
 179                 uint32_t uint8_t_alignment,
 180                 uint32_t uint16_t_alignment,
 181                 uint32_t uint32_t_alignment,
 182                 uint32_t uint64_t_alignment,
 183                 uint32_t long_alignment,
 184                 int byte_order);
 185
 186 void ust_registry_session_destroy(struct ust_registry_session *session);
 187
 188 int ust_registry_create_event(struct ust_registry_session *session,
 189                 struct ust_registry_channel *channel,
 190                 int session_objd, int channel_objd, char *name, char *sig,
 191                 size_t nr_fields, struct ustctl_field *fields, int loglevel,
 192                 char *model_emf_uri, uint32_t *event_id);
 193 struct ust_registry_event *ust_registry_find_event(
 194                 struct ust_registry_channel *chan, char *name, char *sig);
 195 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 196                 struct ust_registry_event *event);
 197
 198 /* app can be NULL for registry shared across applications. */
 199 int ust_metadata_session_statedump(struct ust_registry_session *session,
 200                 struct ust_app *app);
 201 int ust_metadata_channel_statedump(struct ust_registry_session *session,
 202                 struct ust_registry_channel *chan);
 203 int ust_metadata_event_statedump(struct ust_registry_session *session,
 204                 struct ust_registry_channel *chan,
 205                 struct ust_registry_event *event);
 206
 207 #endif /* LTTNG_UST_REGISTRY_H */