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 _LTTNG_CONSUMER_H
  21 #define _LTTNG_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 };
  58
  59 /* State of each fd in consumer */
  60 enum lttng_consumer_stream_state {
  61         LTTNG_CONSUMER_ACTIVE_STREAM,
  62         LTTNG_CONSUMER_PAUSE_STREAM,
  63         LTTNG_CONSUMER_DELETE_STREAM,
  64 };
  65
  66 enum lttng_consumer_type {
  67         LTTNG_CONSUMER_UNKNOWN = 0,
  68         LTTNG_CONSUMER_KERNEL,
  69         LTTNG_CONSUMER64_UST,
  70         LTTNG_CONSUMER32_UST,
  71 };
  72
  73 struct lttng_consumer_channel {
  74         struct lttng_ht_node_ulong node;
  75         int key;
  76         uint64_t max_sb_size; /* the subbuffer size for this channel */
  77         int refcount; /* Number of streams referencing this channel */
  78         /* For UST */
  79         int shm_fd;
  80         int wait_fd;
  81         void *mmap_base;
  82         size_t mmap_len;
  83         struct lttng_ust_shm_handle *handle;
  84         int nr_streams;
  85         int wait_fd_is_copy;
  86         int cpucount;
  87 };
  88
  89 /* Forward declaration for UST. */
  90 struct lttng_ust_lib_ring_buffer;
  91
  92 /*
  93  * Internal representation of the streams, sessiond_key is used to identify
  94  * uniquely a stream.
  95  */
  96 struct lttng_consumer_stream {
  97         struct lttng_ht_node_ulong node;
  98         struct lttng_ht_node_ulong waitfd_node;
  99         struct lttng_consumer_channel *chan;    /* associated channel */
 100         /*
 101          * key is the key used by the session daemon to refer to the
 102          * object in the consumer daemon.
 103          */
 104         int key;
 105         int shm_fd;
 106         int wait_fd;
 107         int out_fd; /* output file to write the data */
 108         off_t out_fd_offset; /* write position in the output file descriptor */
 109         char path_name[PATH_MAX]; /* tracefile name */
 110         enum lttng_consumer_stream_state state;
 111         size_t shm_len;
 112         void *mmap_base;
 113         size_t mmap_len;
 114         enum lttng_event_output output; /* splice or mmap */
 115         int shm_fd_is_copy;
 116         int wait_fd_is_copy;
 117         /* For UST */
 118         struct lttng_ust_lib_ring_buffer *buf;
 119         int cpu;
 120         int data_read;
 121         int hangup_flush_done;
 122         /* UID/GID of the user owning the session to which stream belongs */
 123         uid_t uid;
 124         gid_t gid;
 125         /* Network sequence number. Indicating on which relayd socket it goes. */
 126         int net_seq_idx;
 127         /* Identify if the stream is the metadata */
 128         unsigned int metadata_flag;
 129         /* Used when the stream is set for network streaming */
 130         uint64_t relayd_stream_id;
 131 };
 132
 133 /*
 134  * Internal representation of a relayd socket pair.
 135  */
 136 struct consumer_relayd_sock_pair {
 137         /* Network sequence number. */
 138         int net_seq_idx;
 139         /* Number of stream associated with this relayd */
 140         unsigned int refcount;
 141         pthread_mutex_t ctrl_sock_mutex;
 142         /* Sockets information */
 143         struct lttcomm_sock control_sock;
 144         struct lttcomm_sock data_sock;
 145         struct lttng_ht_node_ulong node;
 146 };
 147
 148 /*
 149  * UST consumer local data to the program. One or more instance per
 150  * process.
 151  */
 152 struct lttng_consumer_local_data {
 153         /*
 154          * Function to call when data is available on a buffer.
 155          * Returns the number of bytes read, or negative error value.
 156          */
 157         ssize_t (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 158                         struct lttng_consumer_local_data *ctx);
 159         /*
 160          * function to call when we receive a new channel, it receives a
 161          * newly allocated channel, depending on the return code of this
 162          * function, the new channel will be handled by the application
 163          * or the library.
 164          *
 165          * Returns:
 166          *    > 0 (success, FD is kept by application)
 167          *   == 0 (success, FD is left to library)
 168          *    < 0 (error)
 169          */
 170         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 171         /*
 172          * function to call when we receive a new stream, it receives a
 173          * newly allocated stream, depending on the return code of this
 174          * function, the new stream will be handled by the application
 175          * or the library.
 176          *
 177          * Returns:
 178          *    > 0 (success, FD is kept by application)
 179          *   == 0 (success, FD is left to library)
 180          *    < 0 (error)
 181          */
 182         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 183         /*
 184          * function to call when a stream is getting updated by the session
 185          * daemon, this function receives the sessiond key and the new
 186          * state, depending on the return code of this function the
 187          * update of state for the stream is 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_update_stream)(int sessiond_key, uint32_t state);
 196         /* socket to communicate errors with sessiond */
 197         int consumer_error_socket;
 198         /* socket to exchange commands with sessiond */
 199         char *consumer_command_sock_path;
 200         /* communication with splice */
 201         int consumer_thread_pipe[2];
 202         /* pipe to wake the poll thread when necessary */
 203         int consumer_poll_pipe[2];
 204         /* to let the signal handler wake up the fd receiver thread */
 205         int consumer_should_quit[2];
 206 };
 207
 208 /*
 209  * Library-level data. One instance per process.
 210  */
 211 struct lttng_consumer_global_data {
 212         /*
 213          * At this time, this lock is used to ensure coherence between the count
 214          * and number of element in the hash table. It's also a protection for
 215          * concurrent read/write between threads.
 216          *
 217          * XXX: We need to see if this lock is still needed with the lockless RCU
 218          * hash tables.
 219          */
 220         pthread_mutex_t lock;
 221
 222         /*
 223          * Number of streams in the hash table. Protected by consumer_data.lock.
 224          */
 225         int stream_count;
 226         /*
 227          * Hash tables of streams and channels. Protected by consumer_data.lock.
 228          */
 229         struct lttng_ht *stream_ht;
 230         struct lttng_ht *channel_ht;
 231         /*
 232          * Flag specifying if the local array of FDs needs update in the
 233          * poll function. Protected by consumer_data.lock.
 234          */
 235         unsigned int need_update;
 236         enum lttng_consumer_type type;
 237
 238         /*
 239          * Relayd socket(s) hashtable indexed by network sequence number. Each
 240          * stream has an index which associate the right relayd socket to use.
 241          */
 242         struct lttng_ht *relayd_ht;
 243 };
 244
 245 /*
 246  * Init consumer data structures.
 247  */
 248 extern void lttng_consumer_init(void);
 249
 250 /*
 251  * Set the error socket for communication with a session daemon.
 252  */
 253 extern void lttng_consumer_set_error_sock(
 254                 struct lttng_consumer_local_data *ctx, int sock);
 255
 256 /*
 257  * Set the command socket path for communication with a session daemon.
 258  */
 259 extern void lttng_consumer_set_command_sock_path(
 260                 struct lttng_consumer_local_data *ctx, char *sock);
 261
 262 /*
 263  * Send return code to session daemon.
 264  *
 265  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 266  * on error.
 267  */
 268 extern int lttng_consumer_send_error(
 269                 struct lttng_consumer_local_data *ctx, int cmd);
 270
 271 /*
 272  * Called from signal handler to ensure a clean exit.
 273  */
 274 extern void lttng_consumer_should_exit(
 275                 struct lttng_consumer_local_data *ctx);
 276
 277 /*
 278  * Cleanup the daemon's socket on exit.
 279  */
 280 extern void lttng_consumer_cleanup(void);
 281
 282 /*
 283  * Flush pending writes to trace output disk file.
 284  */
 285 extern void lttng_consumer_sync_trace_file(
 286                 struct lttng_consumer_stream *stream, off_t orig_offset);
 287
 288 /*
 289  * Poll on the should_quit pipe and the command socket return -1 on error and
 290  * should exit, 0 if data is available on the command socket
 291  */
 292 extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 293
 294 extern int consumer_update_poll_array(
 295                 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
 296                 struct lttng_consumer_stream **local_consumer_streams,
 297                 struct lttng_ht *metadata_ht);
 298
 299 extern struct lttng_consumer_stream *consumer_allocate_stream(
 300                 int channel_key, int stream_key,
 301                 int shm_fd, int wait_fd,
 302                 enum lttng_consumer_stream_state state,
 303                 uint64_t mmap_len,
 304                 enum lttng_event_output output,
 305                 const char *path_name,
 306                 uid_t uid,
 307                 gid_t gid,
 308                 int net_index,
 309                 int metadata_flag);
 310 extern int consumer_add_stream(struct lttng_consumer_stream *stream);
 311 extern void consumer_del_stream(struct lttng_consumer_stream *stream);
 312 extern void consumer_change_stream_state(int stream_key,
 313                 enum lttng_consumer_stream_state state);
 314 extern void consumer_del_channel(struct lttng_consumer_channel *channel);
 315 extern struct lttng_consumer_channel *consumer_allocate_channel(
 316                 int channel_key,
 317                 int shm_fd, int wait_fd,
 318                 uint64_t mmap_len,
 319                 uint64_t max_sb_size);
 320 int consumer_add_channel(struct lttng_consumer_channel *channel);
 321
 322 /* lttng-relayd consumer command */
 323 int consumer_add_relayd(struct consumer_relayd_sock_pair *relayd);
 324 struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair(
 325                 int net_seq_idx);
 326 struct consumer_relayd_sock_pair *consumer_find_relayd(int key);
 327 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
 328                 size_t data_size);
 329
 330 extern struct lttng_consumer_local_data *lttng_consumer_create(
 331                 enum lttng_consumer_type type,
 332                 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
 333                         struct lttng_consumer_local_data *ctx),
 334                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 335                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 336                 int (*update_stream)(int sessiond_key, uint32_t state));
 337 extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 338 extern ssize_t lttng_consumer_on_read_subbuffer_mmap(
 339                 struct lttng_consumer_local_data *ctx,
 340                 struct lttng_consumer_stream *stream, unsigned long len);
 341 extern ssize_t lttng_consumer_on_read_subbuffer_splice(
 342                 struct lttng_consumer_local_data *ctx,
 343                 struct lttng_consumer_stream *stream, unsigned long len);
 344 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 345                 struct lttng_consumer_stream *stream);
 346 extern int lttng_consumer_get_produced_snapshot(
 347                 struct lttng_consumer_local_data *ctx,
 348                 struct lttng_consumer_stream *stream,
 349                 unsigned long *pos);
 350 extern void *lttng_consumer_thread_poll_fds(void *data);
 351 extern void *lttng_consumer_thread_receive_fds(void *data);
 352 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 353                 int sock, struct pollfd *consumer_sockpoll);
 354
 355 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 356                 struct lttng_consumer_local_data *ctx);
 357 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 358
 359 #endif /* _LTTNG_CONSUMER_H */