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         /*
  81          * The number of streams to receive initially. Used to guarantee that we do
  82          * not destroy a channel before receiving all its associated streams.
  83          */
  84         unsigned int nb_init_streams;
  85
  86         /* For UST */
  87         int shm_fd;
  88         int wait_fd;
  89         void *mmap_base;
  90         size_t mmap_len;
  91         struct lttng_ust_shm_handle *handle;
  92         int wait_fd_is_copy;
  93         int cpucount;
  94 };
  95
  96 /* Forward declaration for UST. */
  97 struct lttng_ust_lib_ring_buffer;
  98
  99 /*
 100  * Internal representation of the streams, sessiond_key is used to identify
 101  * uniquely a stream.
 102  */
 103 struct lttng_consumer_stream {
 104         struct lttng_ht_node_ulong node;
 105         struct lttng_ht_node_ulong waitfd_node;
 106         struct lttng_consumer_channel *chan;    /* associated channel */
 107         /*
 108          * key is the key used by the session daemon to refer to the
 109          * object in the consumer daemon.
 110          */
 111         int key;
 112         int shm_fd;
 113         int wait_fd;
 114         int out_fd; /* output file to write the data */
 115         off_t out_fd_offset; /* write position in the output file descriptor */
 116         char path_name[PATH_MAX]; /* tracefile name */
 117         enum lttng_consumer_stream_state state;
 118         size_t shm_len;
 119         void *mmap_base;
 120         size_t mmap_len;
 121         enum lttng_event_output output; /* splice or mmap */
 122         int shm_fd_is_copy;
 123         int wait_fd_is_copy;
 124         /* For UST */
 125         struct lttng_ust_lib_ring_buffer *buf;
 126         int cpu;
 127         int data_read;
 128         int hangup_flush_done;
 129         /* UID/GID of the user owning the session to which stream belongs */
 130         uid_t uid;
 131         gid_t gid;
 132         /* Network sequence number. Indicating on which relayd socket it goes. */
 133         int net_seq_idx;
 134         /* Identify if the stream is the metadata */
 135         unsigned int metadata_flag;
 136         /* Used when the stream is set for network streaming */
 137         uint64_t relayd_stream_id;
 138         /* Next sequence number to use for trace packet */
 139         uint64_t next_net_seq_num;
 140 };
 141
 142 /*
 143  * Internal representation of a relayd socket pair.
 144  */
 145 struct consumer_relayd_sock_pair {
 146         /* Network sequence number. */
 147         int net_seq_idx;
 148         /* Number of stream associated with this relayd */
 149         unsigned int refcount;
 150
 151         /*
 152          * This flag indicates whether or not we should destroy this object. The
 153          * destruction should ONLY occurs when this flag is set and the refcount is
 154          * set to zero.
 155          */
 156         unsigned int destroy_flag;
 157
 158         /*
 159          * Mutex protecting the control socket to avoid out of order packets
 160          * between threads sending data to the relayd. Since metadata data is sent
 161          * over that socket, at least two sendmsg() are needed (header + data)
 162          * creating a race for packets to overlap between threads using it.
 163          */
 164         pthread_mutex_t ctrl_sock_mutex;
 165
 166         /* Control socket. Command and metadata are passed over it */
 167         struct lttcomm_sock control_sock;
 168
 169         /*
 170          * We don't need a mutex at this point since we only splice or write single
 171          * large chunk of data with a header appended at the begining. Moreover,
 172          * this socket is for now only used in a single thread.
 173          */
 174         struct lttcomm_sock data_sock;
 175         struct lttng_ht_node_ulong node;
 176 };
 177
 178 /*
 179  * UST consumer local data to the program. One or more instance per
 180  * process.
 181  */
 182 struct lttng_consumer_local_data {
 183         /*
 184          * Function to call when data is available on a buffer.
 185          * Returns the number of bytes read, or negative error value.
 186          */
 187         ssize_t (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 188                         struct lttng_consumer_local_data *ctx);
 189         /*
 190          * function to call when we receive a new channel, it receives a
 191          * newly allocated channel, depending on the return code of this
 192          * function, the new channel will be handled by the application
 193          * or the library.
 194          *
 195          * Returns:
 196          *    > 0 (success, FD is kept by application)
 197          *   == 0 (success, FD is left to library)
 198          *    < 0 (error)
 199          */
 200         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 201         /*
 202          * function to call when we receive a new stream, it receives a
 203          * newly allocated stream, depending on the return code of this
 204          * function, the new stream will be handled by the application
 205          * or the library.
 206          *
 207          * Returns:
 208          *    > 0 (success, FD is kept by application)
 209          *   == 0 (success, FD is left to library)
 210          *    < 0 (error)
 211          */
 212         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 213         /*
 214          * function to call when a stream is getting updated by the session
 215          * daemon, this function receives the sessiond key and the new
 216          * state, depending on the return code of this function the
 217          * update of state for the stream is handled by the application
 218          * or the library.
 219          *
 220          * Returns:
 221          *    > 0 (success, FD is kept by application)
 222          *   == 0 (success, FD is left to library)
 223          *    < 0 (error)
 224          */
 225         int (*on_update_stream)(int sessiond_key, uint32_t state);
 226         /* socket to communicate errors with sessiond */
 227         int consumer_error_socket;
 228         /* socket to exchange commands with sessiond */
 229         char *consumer_command_sock_path;
 230         /* communication with splice */
 231         int consumer_thread_pipe[2];
 232         int consumer_splice_metadata_pipe[2];
 233         /* pipe to wake the poll thread when necessary */
 234         int consumer_poll_pipe[2];
 235         /* to let the signal handler wake up the fd receiver thread */
 236         int consumer_should_quit[2];
 237         /* Metadata poll thread pipe. Transfer metadata stream to it */
 238         int consumer_metadata_pipe[2];
 239 };
 240
 241 /*
 242  * Library-level data. One instance per process.
 243  */
 244 struct lttng_consumer_global_data {
 245         /*
 246          * At this time, this lock is used to ensure coherence between the count
 247          * and number of element in the hash table. It's also a protection for
 248          * concurrent read/write between threads.
 249          *
 250          * XXX: We need to see if this lock is still needed with the lockless RCU
 251          * hash tables.
 252          */
 253         pthread_mutex_t lock;
 254
 255         /*
 256          * Number of streams in the hash table. Protected by consumer_data.lock.
 257          */
 258         int stream_count;
 259         /*
 260          * Hash tables of streams and channels. Protected by consumer_data.lock.
 261          */
 262         struct lttng_ht *stream_ht;
 263         struct lttng_ht *channel_ht;
 264         /*
 265          * Flag specifying if the local array of FDs needs update in the
 266          * poll function. Protected by consumer_data.lock.
 267          */
 268         unsigned int need_update;
 269         enum lttng_consumer_type type;
 270
 271         /*
 272          * Relayd socket(s) hashtable indexed by network sequence number. Each
 273          * stream has an index which associate the right relayd socket to use.
 274          */
 275         struct lttng_ht *relayd_ht;
 276 };
 277
 278 /*
 279  * Init consumer data structures.
 280  */
 281 extern void lttng_consumer_init(void);
 282
 283 /*
 284  * Set the error socket for communication with a session daemon.
 285  */
 286 extern void lttng_consumer_set_error_sock(
 287                 struct lttng_consumer_local_data *ctx, int sock);
 288
 289 /*
 290  * Set the command socket path for communication with a session daemon.
 291  */
 292 extern void lttng_consumer_set_command_sock_path(
 293                 struct lttng_consumer_local_data *ctx, char *sock);
 294
 295 /*
 296  * Send return code to session daemon.
 297  *
 298  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 299  * on error.
 300  */
 301 extern int lttng_consumer_send_error(
 302                 struct lttng_consumer_local_data *ctx, int cmd);
 303
 304 /*
 305  * Called from signal handler to ensure a clean exit.
 306  */
 307 extern void lttng_consumer_should_exit(
 308                 struct lttng_consumer_local_data *ctx);
 309
 310 /*
 311  * Cleanup the daemon's socket on exit.
 312  */
 313 extern void lttng_consumer_cleanup(void);
 314
 315 /*
 316  * Flush pending writes to trace output disk file.
 317  */
 318 extern void lttng_consumer_sync_trace_file(
 319                 struct lttng_consumer_stream *stream, off_t orig_offset);
 320
 321 /*
 322  * Poll on the should_quit pipe and the command socket return -1 on error and
 323  * should exit, 0 if data is available on the command socket
 324  */
 325 extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 326
 327 extern int consumer_update_poll_array(
 328                 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
 329                 struct lttng_consumer_stream **local_consumer_streams);
 330
 331 extern struct lttng_consumer_stream *consumer_allocate_stream(
 332                 int channel_key, int stream_key,
 333                 int shm_fd, int wait_fd,
 334                 enum lttng_consumer_stream_state state,
 335                 uint64_t mmap_len,
 336                 enum lttng_event_output output,
 337                 const char *path_name,
 338                 uid_t uid,
 339                 gid_t gid,
 340                 int net_index,
 341                 int metadata_flag,
 342                 int *alloc_ret);
 343 extern int consumer_add_stream(struct lttng_consumer_stream *stream);
 344 extern void consumer_del_stream(struct lttng_consumer_stream *stream);
 345 extern void consumer_change_stream_state(int stream_key,
 346                 enum lttng_consumer_stream_state state);
 347 extern void consumer_del_channel(struct lttng_consumer_channel *channel);
 348 extern struct lttng_consumer_channel *consumer_allocate_channel(
 349                 int channel_key,
 350                 int shm_fd, int wait_fd,
 351                 uint64_t mmap_len,
 352                 uint64_t max_sb_size,
 353                 unsigned int nb_init_streams);
 354 int consumer_add_channel(struct lttng_consumer_channel *channel);
 355
 356 /* lttng-relayd consumer command */
 357 struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair(
 358                 int net_seq_idx);
 359 struct consumer_relayd_sock_pair *consumer_find_relayd(int key);
 360 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
 361                 size_t data_size);
 362
 363 extern struct lttng_consumer_local_data *lttng_consumer_create(
 364                 enum lttng_consumer_type type,
 365                 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
 366                         struct lttng_consumer_local_data *ctx),
 367                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 368                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 369                 int (*update_stream)(int sessiond_key, uint32_t state));
 370 extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 371 extern ssize_t lttng_consumer_on_read_subbuffer_mmap(
 372                 struct lttng_consumer_local_data *ctx,
 373                 struct lttng_consumer_stream *stream, unsigned long len,
 374                 unsigned long padding);
 375 extern ssize_t lttng_consumer_on_read_subbuffer_splice(
 376                 struct lttng_consumer_local_data *ctx,
 377                 struct lttng_consumer_stream *stream, unsigned long len,
 378                 unsigned long padding);
 379 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 380                 struct lttng_consumer_stream *stream);
 381 extern int lttng_consumer_get_produced_snapshot(
 382                 struct lttng_consumer_local_data *ctx,
 383                 struct lttng_consumer_stream *stream,
 384                 unsigned long *pos);
 385 extern void *lttng_consumer_thread_poll_fds(void *data);
 386 extern void *lttng_consumer_thread_receive_fds(void *data);
 387 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 388                 int sock, struct pollfd *consumer_sockpoll);
 389
 390 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 391                 struct lttng_consumer_local_data *ctx);
 392 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 393 int consumer_add_relayd_socket(int net_seq_idx, int sock_type,
 394                 struct lttng_consumer_local_data *ctx, int sock,
 395                 struct pollfd *consumer_sockpoll, struct lttcomm_sock *relayd_sock);
 396 void consumer_flag_relayd_for_destroy(
 397                 struct consumer_relayd_sock_pair *relayd);
 398
 399 #endif /* LIB_CONSUMER_H */