src/common/consumer.h

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *               2012 - David Goulet <dgoulet@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef LIB_CONSUMER_H
  21 #define LIB_CONSUMER_H
  22
  23 #include <limits.h>
  24 #include <poll.h>
  25 #include <unistd.h>
  26
  27 #include <lttng/lttng.h>
  28
  29 #include <common/hashtable/hashtable.h>
  30 #include <common/compat/fcntl.h>
  31 #include <common/sessiond-comm/sessiond-comm.h>
  32
  33 /*
  34  * When the receiving thread dies, we need to have a way to make the polling
  35  * thread exit eventually. If all FDs hang up (normal case when the
  36  * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
  37  * for whatever reason some FDs remain open, the consumer should still exit
  38  * eventually.
  39  *
  40  * If the timeout is reached, it means that during this period no events
  41  * occurred on the FDs so we need to force an exit. This case should not happen
  42  * but it is a safety to ensure we won't block the consumer indefinitely.
  43  *
  44  * The value of 2 seconds is an arbitrary choice.
  45  */
  46 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
  47
  48 /* Commands for consumer */
  49 enum lttng_consumer_command {
  50         LTTNG_CONSUMER_ADD_CHANNEL,
  51         LTTNG_CONSUMER_ADD_STREAM,
  52         /* pause, delete, active depending on fd state */
  53         LTTNG_CONSUMER_UPDATE_STREAM,
  54         /* inform the consumer to quit when all fd has hang up */
  55         LTTNG_CONSUMER_STOP,
  56         LTTNG_CONSUMER_ADD_RELAYD_SOCKET,
  57         /* Inform the consumer to kill a specific relayd connection */
  58         LTTNG_CONSUMER_DESTROY_RELAYD,
  59         /* Return to the sessiond if there is data pending for a session */
  60         LTTNG_CONSUMER_DATA_AVAILABLE,
  61 };
  62
  63 /* State of each fd in consumer */
  64 enum lttng_consumer_stream_state {
  65         LTTNG_CONSUMER_ACTIVE_STREAM,
  66         LTTNG_CONSUMER_PAUSE_STREAM,
  67         LTTNG_CONSUMER_DELETE_STREAM,
  68 };
  69
  70 enum lttng_consumer_type {
  71         LTTNG_CONSUMER_UNKNOWN = 0,
  72         LTTNG_CONSUMER_KERNEL,
  73         LTTNG_CONSUMER64_UST,
  74         LTTNG_CONSUMER32_UST,
  75 };
  76
  77 struct lttng_consumer_channel {
  78         struct lttng_ht_node_ulong node;
  79         int key;
  80         uint64_t max_sb_size; /* the subbuffer size for this channel */
  81         int refcount; /* Number of streams referencing this channel */
  82         /*
  83          * The number of streams to receive initially. Used to guarantee that we do
  84          * not destroy a channel before receiving all its associated streams.
  85          */
  86         unsigned int nb_init_streams;
  87
  88         /* For UST */
  89         int shm_fd;
  90         int wait_fd;
  91         void *mmap_base;
  92         size_t mmap_len;
  93         struct lttng_ust_shm_handle *handle;
  94         int wait_fd_is_copy;
  95         int cpucount;
  96 };
  97
  98 /* Forward declaration for UST. */
  99 struct lttng_ust_lib_ring_buffer;
 100
 101 /*
 102  * Internal representation of the streams, sessiond_key is used to identify
 103  * uniquely a stream.
 104  */
 105 struct lttng_consumer_stream {
 106         /* HT node used by the data_ht and metadata_ht */
 107         struct lttng_ht_node_ulong node;
 108         /* HT node used in consumer_data.stream_list_ht */
 109         struct lttng_ht_node_ulong node_session_id;
 110         struct lttng_consumer_channel *chan;    /* associated channel */
 111         /*
 112          * key is the key used by the session daemon to refer to the
 113          * object in the consumer daemon.
 114          */
 115         int key;
 116         int shm_fd;
 117         int wait_fd;
 118         int out_fd; /* output file to write the data */
 119         off_t out_fd_offset; /* write position in the output file descriptor */
 120         char path_name[PATH_MAX]; /* tracefile name */
 121         enum lttng_consumer_stream_state state;
 122         size_t shm_len;
 123         void *mmap_base;
 124         size_t mmap_len;
 125         enum lttng_event_output output; /* splice or mmap */
 126         int shm_fd_is_copy;
 127         int wait_fd_is_copy;
 128         /* For UST */
 129         struct lttng_ust_lib_ring_buffer *buf;
 130         int cpu;
 131         int data_read;
 132         int hangup_flush_done;
 133         /* UID/GID of the user owning the session to which stream belongs */
 134         uid_t uid;
 135         gid_t gid;
 136         /* Network sequence number. Indicating on which relayd socket it goes. */
 137         int net_seq_idx;
 138         /* Identify if the stream is the metadata */
 139         unsigned int metadata_flag;
 140         /* Used when the stream is set for network streaming */
 141         uint64_t relayd_stream_id;
 142         /* Next sequence number to use for trace packet */
 143         uint64_t next_net_seq_num;
 144         /* Lock to use the stream FDs since they are used between threads. */
 145         pthread_mutex_t lock;
 146         /* Tracing session id */
 147         uint64_t session_id;
 148 };
 149
 150 /*
 151  * Internal representation of a relayd socket pair.
 152  */
 153 struct consumer_relayd_sock_pair {
 154         /* Network sequence number. */
 155         int net_seq_idx;
 156         /* Number of stream associated with this relayd */
 157         unsigned int refcount;
 158
 159         /*
 160          * This flag indicates whether or not we should destroy this object. The
 161          * destruction should ONLY occurs when this flag is set and the refcount is
 162          * set to zero.
 163          */
 164         unsigned int destroy_flag;
 165
 166         /*
 167          * Mutex protecting the control socket to avoid out of order packets
 168          * between threads sending data to the relayd. Since metadata data is sent
 169          * over that socket, at least two sendmsg() are needed (header + data)
 170          * creating a race for packets to overlap between threads using it.
 171          */
 172         pthread_mutex_t ctrl_sock_mutex;
 173
 174         /* Control socket. Command and metadata are passed over it */
 175         struct lttcomm_sock control_sock;
 176
 177         /*
 178          * We don't need a mutex at this point since we only splice or write single
 179          * large chunk of data with a header appended at the begining. Moreover,
 180          * this socket is for now only used in a single thread.
 181          */
 182         struct lttcomm_sock data_sock;
 183         struct lttng_ht_node_ulong node;
 184 };
 185
 186 /*
 187  * UST consumer local data to the program. One or more instance per
 188  * process.
 189  */
 190 struct lttng_consumer_local_data {
 191         /*
 192          * Function to call when data is available on a buffer.
 193          * Returns the number of bytes read, or negative error value.
 194          */
 195         ssize_t (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 196                         struct lttng_consumer_local_data *ctx);
 197         /*
 198          * function to call when we receive a new channel, it receives a
 199          * newly allocated channel, depending on the return code of this
 200          * function, the new channel will be handled by the application
 201          * or the library.
 202          *
 203          * Returns:
 204          *    > 0 (success, FD is kept by application)
 205          *   == 0 (success, FD is left to library)
 206          *    < 0 (error)
 207          */
 208         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 209         /*
 210          * function to call when we receive a new stream, it receives a
 211          * newly allocated stream, depending on the return code of this
 212          * function, the new stream will be handled by the application
 213          * or the library.
 214          *
 215          * Returns:
 216          *    > 0 (success, FD is kept by application)
 217          *   == 0 (success, FD is left to library)
 218          *    < 0 (error)
 219          */
 220         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 221         /*
 222          * function to call when a stream is getting updated by the session
 223          * daemon, this function receives the sessiond key and the new
 224          * state, depending on the return code of this function the
 225          * update of state for the stream is handled by the application
 226          * or the library.
 227          *
 228          * Returns:
 229          *    > 0 (success, FD is kept by application)
 230          *   == 0 (success, FD is left to library)
 231          *    < 0 (error)
 232          */
 233         int (*on_update_stream)(int sessiond_key, uint32_t state);
 234         /* socket to communicate errors with sessiond */
 235         int consumer_error_socket;
 236         /* socket to exchange commands with sessiond */
 237         char *consumer_command_sock_path;
 238         /* communication with splice */
 239         int consumer_thread_pipe[2];
 240         int consumer_splice_metadata_pipe[2];
 241         /* Data stream poll thread pipe. To transfer data stream to the thread */
 242         int consumer_data_pipe[2];
 243         /* to let the signal handler wake up the fd receiver thread */
 244         int consumer_should_quit[2];
 245         /* Metadata poll thread pipe. Transfer metadata stream to it */
 246         int consumer_metadata_pipe[2];
 247 };
 248
 249 /*
 250  * Library-level data. One instance per process.
 251  */
 252 struct lttng_consumer_global_data {
 253         /*
 254          * At this time, this lock is used to ensure coherence between the count
 255          * and number of element in the hash table. It's also a protection for
 256          * concurrent read/write between threads.
 257          *
 258          * XXX: We need to see if this lock is still needed with the lockless RCU
 259          * hash tables.
 260          */
 261         pthread_mutex_t lock;
 262
 263         /*
 264          * Number of streams in the data stream hash table declared outside.
 265          * Protected by consumer_data.lock.
 266          */
 267         int stream_count;
 268
 269         /* Channel hash table protected by consumer_data.lock. */
 270         struct lttng_ht *channel_ht;
 271         /*
 272          * Flag specifying if the local array of FDs needs update in the
 273          * poll function. Protected by consumer_data.lock.
 274          */
 275         unsigned int need_update;
 276         enum lttng_consumer_type type;
 277
 278         /*
 279          * Relayd socket(s) hashtable indexed by network sequence number. Each
 280          * stream has an index which associate the right relayd socket to use.
 281          */
 282         struct lttng_ht *relayd_ht;
 283
 284         /*
 285          * This hash table contains all streams (metadata and data) indexed by
 286          * session id. In other words, the ht is indexed by session id and each
 287          * bucket contains the list of associated streams.
 288          *
 289          * This HT uses the "node_session_id" of the consumer stream.
 290          */
 291         struct lttng_ht *stream_list_ht;
 292 };
 293
 294 /* Defined in consumer.c and coupled with explanations */
 295 extern struct lttng_ht *metadata_ht;
 296 extern struct lttng_ht *data_ht;
 297
 298 /*
 299  * Init consumer data structures.
 300  */
 301 extern void lttng_consumer_init(void);
 302
 303 /*
 304  * Set the error socket for communication with a session daemon.
 305  */
 306 extern void lttng_consumer_set_error_sock(
 307                 struct lttng_consumer_local_data *ctx, int sock);
 308
 309 /*
 310  * Set the command socket path for communication with a session daemon.
 311  */
 312 extern void lttng_consumer_set_command_sock_path(
 313                 struct lttng_consumer_local_data *ctx, char *sock);
 314
 315 /*
 316  * Send return code to session daemon.
 317  *
 318  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 319  * on error.
 320  */
 321 extern int lttng_consumer_send_error(
 322                 struct lttng_consumer_local_data *ctx, int cmd);
 323
 324 /*
 325  * Called from signal handler to ensure a clean exit.
 326  */
 327 extern void lttng_consumer_should_exit(
 328                 struct lttng_consumer_local_data *ctx);
 329
 330 /*
 331  * Cleanup the daemon's socket on exit.
 332  */
 333 extern void lttng_consumer_cleanup(void);
 334
 335 /*
 336  * Flush pending writes to trace output disk file.
 337  */
 338 extern void lttng_consumer_sync_trace_file(
 339                 struct lttng_consumer_stream *stream, off_t orig_offset);
 340
 341 /*
 342  * Poll on the should_quit pipe and the command socket return -1 on error and
 343  * should exit, 0 if data is available on the command socket
 344  */
 345 extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 346
 347 extern struct lttng_consumer_stream *consumer_allocate_stream(
 348                 int channel_key, int stream_key,
 349                 int shm_fd, int wait_fd,
 350                 enum lttng_consumer_stream_state state,
 351                 uint64_t mmap_len,
 352                 enum lttng_event_output output,
 353                 const char *path_name,
 354                 uid_t uid,
 355                 gid_t gid,
 356                 int net_index,
 357                 int metadata_flag,
 358                 uint64_t session_id,
 359                 int *alloc_ret);
 360 extern void consumer_del_stream(struct lttng_consumer_stream *stream,
 361                 struct lttng_ht *ht);
 362 extern void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
 363                 struct lttng_ht *ht);
 364 extern void consumer_del_channel(struct lttng_consumer_channel *channel);
 365 extern struct lttng_consumer_channel *consumer_allocate_channel(
 366                 int channel_key,
 367                 int shm_fd, int wait_fd,
 368                 uint64_t mmap_len,
 369                 uint64_t max_sb_size,
 370                 unsigned int nb_init_streams);
 371 int consumer_add_channel(struct lttng_consumer_channel *channel);
 372
 373 /* lttng-relayd consumer command */
 374 struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair(
 375                 int net_seq_idx);
 376 struct consumer_relayd_sock_pair *consumer_find_relayd(int key);
 377 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
 378                 size_t data_size);
 379 void consumer_steal_stream_key(int key, struct lttng_ht *ht);
 380
 381 extern struct lttng_consumer_local_data *lttng_consumer_create(
 382                 enum lttng_consumer_type type,
 383                 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
 384                         struct lttng_consumer_local_data *ctx),
 385                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 386                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 387                 int (*update_stream)(int sessiond_key, uint32_t state));
 388 extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 389 extern ssize_t lttng_consumer_on_read_subbuffer_mmap(
 390                 struct lttng_consumer_local_data *ctx,
 391                 struct lttng_consumer_stream *stream, unsigned long len,
 392                 unsigned long padding);
 393 extern ssize_t lttng_consumer_on_read_subbuffer_splice(
 394                 struct lttng_consumer_local_data *ctx,
 395                 struct lttng_consumer_stream *stream, unsigned long len,
 396                 unsigned long padding);
 397 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 398                 struct lttng_consumer_stream *stream);
 399 extern int lttng_consumer_get_produced_snapshot(
 400                 struct lttng_consumer_local_data *ctx,
 401                 struct lttng_consumer_stream *stream,
 402                 unsigned long *pos);
 403 extern void *consumer_thread_metadata_poll(void *data);
 404 extern void *consumer_thread_data_poll(void *data);
 405 extern void *consumer_thread_sessiond_poll(void *data);
 406 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 407                 int sock, struct pollfd *consumer_sockpoll);
 408
 409 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 410                 struct lttng_consumer_local_data *ctx);
 411 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 412 int consumer_add_relayd_socket(int net_seq_idx, int sock_type,
 413                 struct lttng_consumer_local_data *ctx, int sock,
 414                 struct pollfd *consumer_sockpoll, struct lttcomm_sock *relayd_sock);
 415 void consumer_flag_relayd_for_destroy(
 416                 struct consumer_relayd_sock_pair *relayd);
 417
 418 #endif /* LIB_CONSUMER_H */