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 };
  60
  61 /* State of each fd in consumer */
  62 enum lttng_consumer_stream_state {
  63         LTTNG_CONSUMER_ACTIVE_STREAM,
  64         LTTNG_CONSUMER_PAUSE_STREAM,
  65         LTTNG_CONSUMER_DELETE_STREAM,
  66 };
  67
  68 enum lttng_consumer_type {
  69         LTTNG_CONSUMER_UNKNOWN = 0,
  70         LTTNG_CONSUMER_KERNEL,
  71         LTTNG_CONSUMER64_UST,
  72         LTTNG_CONSUMER32_UST,
  73 };
  74
  75 struct lttng_consumer_channel {
  76         struct lttng_ht_node_ulong node;
  77         int key;
  78         uint64_t max_sb_size; /* the subbuffer size for this channel */
  79         int refcount; /* Number of streams referencing this channel */
  80         /* For UST */
  81         int shm_fd;
  82         int wait_fd;
  83         void *mmap_base;
  84         size_t mmap_len;
  85         struct lttng_ust_shm_handle *handle;
  86         int wait_fd_is_copy;
  87         int cpucount;
  88 };
  89
  90 /* Forward declaration for UST. */
  91 struct lttng_ust_lib_ring_buffer;
  92
  93 /*
  94  * Internal representation of the streams, sessiond_key is used to identify
  95  * uniquely a stream.
  96  */
  97 struct lttng_consumer_stream {
  98         struct lttng_ht_node_ulong node;
  99         struct lttng_ht_node_ulong waitfd_node;
 100         struct lttng_consumer_channel *chan;    /* associated channel */
 101         /*
 102          * key is the key used by the session daemon to refer to the
 103          * object in the consumer daemon.
 104          */
 105         int key;
 106         int shm_fd;
 107         int wait_fd;
 108         int out_fd; /* output file to write the data */
 109         off_t out_fd_offset; /* write position in the output file descriptor */
 110         char path_name[PATH_MAX]; /* tracefile name */
 111         enum lttng_consumer_stream_state state;
 112         size_t shm_len;
 113         void *mmap_base;
 114         size_t mmap_len;
 115         enum lttng_event_output output; /* splice or mmap */
 116         int shm_fd_is_copy;
 117         int wait_fd_is_copy;
 118         /* For UST */
 119         struct lttng_ust_lib_ring_buffer *buf;
 120         int cpu;
 121         int data_read;
 122         int hangup_flush_done;
 123         /* UID/GID of the user owning the session to which stream belongs */
 124         uid_t uid;
 125         gid_t gid;
 126         /* Network sequence number. Indicating on which relayd socket it goes. */
 127         int net_seq_idx;
 128         /* Identify if the stream is the metadata */
 129         unsigned int metadata_flag;
 130         /* Used when the stream is set for network streaming */
 131         uint64_t relayd_stream_id;
 132         /* Next sequence number to use for trace packet */
 133         uint64_t next_net_seq_num;
 134 };
 135
 136 /*
 137  * Internal representation of a relayd socket pair.
 138  */
 139 struct consumer_relayd_sock_pair {
 140         /* Network sequence number. */
 141         int net_seq_idx;
 142         /* Number of stream associated with this relayd */
 143         unsigned int refcount;
 144
 145         /*
 146          * This flag indicates whether or not we should destroy this object. The
 147          * destruction should ONLY occurs when this flag is set and the refcount is
 148          * set to zero.
 149          */
 150         unsigned int destroy_flag;
 151
 152         /*
 153          * Mutex protecting the control socket to avoid out of order packets
 154          * between threads sending data to the relayd. Since metadata data is sent
 155          * over that socket, at least two sendmsg() are needed (header + data)
 156          * creating a race for packets to overlap between threads using it.
 157          */
 158         pthread_mutex_t ctrl_sock_mutex;
 159
 160         /* Control socket. Command and metadata are passed over it */
 161         struct lttcomm_sock control_sock;
 162
 163         /*
 164          * We don't need a mutex at this point since we only splice or write single
 165          * large chunk of data with a header appended at the begining. Moreover,
 166          * this socket is for now only used in a single thread.
 167          */
 168         struct lttcomm_sock data_sock;
 169         struct lttng_ht_node_ulong node;
 170 };
 171
 172 /*
 173  * UST consumer local data to the program. One or more instance per
 174  * process.
 175  */
 176 struct lttng_consumer_local_data {
 177         /*
 178          * Function to call when data is available on a buffer.
 179          * Returns the number of bytes read, or negative error value.
 180          */
 181         ssize_t (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 182                         struct lttng_consumer_local_data *ctx);
 183         /*
 184          * function to call when we receive a new channel, it receives a
 185          * newly allocated channel, depending on the return code of this
 186          * function, the new channel will be handled by the application
 187          * or the library.
 188          *
 189          * Returns:
 190          *    > 0 (success, FD is kept by application)
 191          *   == 0 (success, FD is left to library)
 192          *    < 0 (error)
 193          */
 194         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 195         /*
 196          * function to call when we receive a new stream, it receives a
 197          * newly allocated stream, depending on the return code of this
 198          * function, the new stream will be handled by the application
 199          * or the library.
 200          *
 201          * Returns:
 202          *    > 0 (success, FD is kept by application)
 203          *   == 0 (success, FD is left to library)
 204          *    < 0 (error)
 205          */
 206         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 207         /*
 208          * function to call when a stream is getting updated by the session
 209          * daemon, this function receives the sessiond key and the new
 210          * state, depending on the return code of this function the
 211          * update of state for the stream is handled by the application
 212          * or the library.
 213          *
 214          * Returns:
 215          *    > 0 (success, FD is kept by application)
 216          *   == 0 (success, FD is left to library)
 217          *    < 0 (error)
 218          */
 219         int (*on_update_stream)(int sessiond_key, uint32_t state);
 220         /* socket to communicate errors with sessiond */
 221         int consumer_error_socket;
 222         /* socket to exchange commands with sessiond */
 223         char *consumer_command_sock_path;
 224         /* communication with splice */
 225         int consumer_thread_pipe[2];
 226         int consumer_splice_metadata_pipe[2];
 227         /* pipe to wake the poll thread when necessary */
 228         int consumer_poll_pipe[2];
 229         /* to let the signal handler wake up the fd receiver thread */
 230         int consumer_should_quit[2];
 231         /* Metadata poll thread pipe. Transfer metadata stream to it */
 232         int consumer_metadata_pipe[2];
 233 };
 234
 235 /*
 236  * Library-level data. One instance per process.
 237  */
 238 struct lttng_consumer_global_data {
 239         /*
 240          * At this time, this lock is used to ensure coherence between the count
 241          * and number of element in the hash table. It's also a protection for
 242          * concurrent read/write between threads.
 243          *
 244          * XXX: We need to see if this lock is still needed with the lockless RCU
 245          * hash tables.
 246          */
 247         pthread_mutex_t lock;
 248
 249         /*
 250          * Number of streams in the hash table. Protected by consumer_data.lock.
 251          */
 252         int stream_count;
 253         /*
 254          * Hash tables of streams and channels. Protected by consumer_data.lock.
 255          */
 256         struct lttng_ht *stream_ht;
 257         struct lttng_ht *channel_ht;
 258         /*
 259          * Flag specifying if the local array of FDs needs update in the
 260          * poll function. Protected by consumer_data.lock.
 261          */
 262         unsigned int need_update;
 263         enum lttng_consumer_type type;
 264
 265         /*
 266          * Relayd socket(s) hashtable indexed by network sequence number. Each
 267          * stream has an index which associate the right relayd socket to use.
 268          */
 269         struct lttng_ht *relayd_ht;
 270 };
 271
 272 /*
 273  * Init consumer data structures.
 274  */
 275 extern void lttng_consumer_init(void);
 276
 277 /*
 278  * Set the error socket for communication with a session daemon.
 279  */
 280 extern void lttng_consumer_set_error_sock(
 281                 struct lttng_consumer_local_data *ctx, int sock);
 282
 283 /*
 284  * Set the command socket path for communication with a session daemon.
 285  */
 286 extern void lttng_consumer_set_command_sock_path(
 287                 struct lttng_consumer_local_data *ctx, char *sock);
 288
 289 /*
 290  * Send return code to session daemon.
 291  *
 292  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 293  * on error.
 294  */
 295 extern int lttng_consumer_send_error(
 296                 struct lttng_consumer_local_data *ctx, int cmd);
 297
 298 /*
 299  * Called from signal handler to ensure a clean exit.
 300  */
 301 extern void lttng_consumer_should_exit(
 302                 struct lttng_consumer_local_data *ctx);
 303
 304 /*
 305  * Cleanup the daemon's socket on exit.
 306  */
 307 extern void lttng_consumer_cleanup(void);
 308
 309 /*
 310  * Flush pending writes to trace output disk file.
 311  */
 312 extern void lttng_consumer_sync_trace_file(
 313                 struct lttng_consumer_stream *stream, off_t orig_offset);
 314
 315 /*
 316  * Poll on the should_quit pipe and the command socket return -1 on error and
 317  * should exit, 0 if data is available on the command socket
 318  */
 319 extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 320
 321 extern int consumer_update_poll_array(
 322                 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
 323                 struct lttng_consumer_stream **local_consumer_streams);
 324
 325 extern struct lttng_consumer_stream *consumer_allocate_stream(
 326                 int channel_key, int stream_key,
 327                 int shm_fd, int wait_fd,
 328                 enum lttng_consumer_stream_state state,
 329                 uint64_t mmap_len,
 330                 enum lttng_event_output output,
 331                 const char *path_name,
 332                 uid_t uid,
 333                 gid_t gid,
 334                 int net_index,
 335                 int metadata_flag);
 336 extern int consumer_add_stream(struct lttng_consumer_stream *stream);
 337 extern void consumer_del_stream(struct lttng_consumer_stream *stream);
 338 extern void consumer_change_stream_state(int stream_key,
 339                 enum lttng_consumer_stream_state state);
 340 extern void consumer_del_channel(struct lttng_consumer_channel *channel);
 341 extern struct lttng_consumer_channel *consumer_allocate_channel(
 342                 int channel_key,
 343                 int shm_fd, int wait_fd,
 344                 uint64_t mmap_len,
 345                 uint64_t max_sb_size);
 346 int consumer_add_channel(struct lttng_consumer_channel *channel);
 347
 348 /* lttng-relayd consumer command */
 349 int consumer_add_relayd(struct consumer_relayd_sock_pair *relayd);
 350 struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair(
 351                 int net_seq_idx);
 352 struct consumer_relayd_sock_pair *consumer_find_relayd(int key);
 353 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
 354                 size_t data_size);
 355 void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd);
 356
 357 extern struct lttng_consumer_local_data *lttng_consumer_create(
 358                 enum lttng_consumer_type type,
 359                 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
 360                         struct lttng_consumer_local_data *ctx),
 361                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 362                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 363                 int (*update_stream)(int sessiond_key, uint32_t state));
 364 extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 365 extern ssize_t lttng_consumer_on_read_subbuffer_mmap(
 366                 struct lttng_consumer_local_data *ctx,
 367                 struct lttng_consumer_stream *stream, unsigned long len,
 368                 unsigned long padding);
 369 extern ssize_t lttng_consumer_on_read_subbuffer_splice(
 370                 struct lttng_consumer_local_data *ctx,
 371                 struct lttng_consumer_stream *stream, unsigned long len,
 372                 unsigned long padding);
 373 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 374                 struct lttng_consumer_stream *stream);
 375 extern int lttng_consumer_get_produced_snapshot(
 376                 struct lttng_consumer_local_data *ctx,
 377                 struct lttng_consumer_stream *stream,
 378                 unsigned long *pos);
 379 extern void *lttng_consumer_thread_poll_fds(void *data);
 380 extern void *lttng_consumer_thread_receive_fds(void *data);
 381 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 382                 int sock, struct pollfd *consumer_sockpoll);
 383
 384 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 385                 struct lttng_consumer_local_data *ctx);
 386 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 387 int consumer_add_relayd_socket(int net_seq_idx, int sock_type,
 388                 struct lttng_consumer_local_data *ctx, int sock,
 389                 struct pollfd *consumer_sockpoll, struct lttcomm_sock *relayd_sock);
 390 void consumer_flag_relayd_for_destroy(
 391                 struct consumer_relayd_sock_pair *relayd);
 392
 393 #endif /* LIB_CONSUMER_H */