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