include/lttng/lttng-consumer.h

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  * Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; only version 2
   8  * of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifndef _LTTNG_CONSUMER_H
  21 #define _LTTNG_CONSUMER_H
  22
  23 #include <limits.h>
  24 #include <poll.h>
  25 #include <urcu/list.h>
  26 #include <lttng/lttng.h>
  27
  28 /*
  29  * When the receiving thread dies, we need to have a way to make the polling
  30  * thread exit eventually. If all FDs hang up (normal case when the
  31  * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
  32  * for whatever reason some FDs remain open, the consumer should still exit
  33  * eventually.
  34  *
  35  * If the timeout is reached, it means that during this period no events
  36  * occurred on the FDs so we need to force an exit. This case should not happen
  37  * but it is a safety to ensure we won't block the consumer indefinitely.
  38  *
  39  * The value of 2 seconds is an arbitrary choice.
  40  */
  41 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
  42
  43 /* Commands for consumer */
  44 enum lttng_consumer_command {
  45         LTTNG_CONSUMER_ADD_CHANNEL,
  46         LTTNG_CONSUMER_ADD_STREAM,
  47         /* pause, delete, active depending on fd state */
  48         LTTNG_CONSUMER_UPDATE_STREAM,
  49         /* inform the consumer to quit when all fd has hang up */
  50         LTTNG_CONSUMER_STOP,
  51 };
  52
  53 /* State of each fd in consumer */
  54 enum lttng_consumer_stream_state {
  55         LTTNG_CONSUMER_ACTIVE_STREAM,
  56         LTTNG_CONSUMER_PAUSE_STREAM,
  57         LTTNG_CONSUMER_DELETE_STREAM,
  58 };
  59
  60 struct lttng_consumer_channel_list {
  61         struct cds_list_head head;
  62 };
  63
  64 struct lttng_consumer_stream_list {
  65         struct cds_list_head head;
  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 cds_list_head list;
  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 shm_fd_is_copy;
  88         int wait_fd_is_copy;
  89         int cpucount;
  90 };
  91
  92 /* Forward declaration for UST. */
  93 struct lttng_ust_lib_ring_buffer;
  94
  95 /*
  96  * Internal representation of the streams, sessiond_key is used to identify
  97  * uniquely a stream.
  98  */
  99 struct lttng_consumer_stream {
 100         struct cds_list_head list;
 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 hangup_flush_done;
 123 };
 124
 125 /*
 126  * UST consumer local data to the program. One or more instance per
 127  * process.
 128  */
 129 struct lttng_consumer_local_data {
 130         /* function to call when data is available on a buffer */
 131         int (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 132                         struct lttng_consumer_local_data *ctx);
 133         /*
 134          * function to call when we receive a new channel, it receives a
 135          * newly allocated channel, depending on the return code of this
 136          * function, the new channel will be handled by the application
 137          * or the library.
 138          *
 139          * Returns:
 140          *    > 0 (success, FD is kept by application)
 141          *   == 0 (success, FD is left to library)
 142          *    < 0 (error)
 143          */
 144         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 145         /*
 146          * function to call when we receive a new stream, it receives a
 147          * newly allocated stream, depending on the return code of this
 148          * function, the new stream will be handled by the application
 149          * or the library.
 150          *
 151          * Returns:
 152          *    > 0 (success, FD is kept by application)
 153          *   == 0 (success, FD is left to library)
 154          *    < 0 (error)
 155          */
 156         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 157         /*
 158          * function to call when a stream is getting updated by the session
 159          * daemon, this function receives the sessiond key and the new
 160          * state, depending on the return code of this function the
 161          * update of state for the stream is handled by the application
 162          * or the library.
 163          *
 164          * Returns:
 165          *    > 0 (success, FD is kept by application)
 166          *   == 0 (success, FD is left to library)
 167          *    < 0 (error)
 168          */
 169         int (*on_update_stream)(int sessiond_key, uint32_t state);
 170         /* socket to communicate errors with sessiond */
 171         int consumer_error_socket;
 172         /* socket to exchange commands with sessiond */
 173         char *consumer_command_sock_path;
 174         /* communication with splice */
 175         int consumer_thread_pipe[2];
 176         /* pipe to wake the poll thread when necessary */
 177         int consumer_poll_pipe[2];
 178         /* to let the signal handler wake up the fd receiver thread */
 179         int consumer_should_quit[2];
 180 };
 181
 182 /*
 183  * Library-level data. One instance per process.
 184  */
 185 struct lttng_consumer_global_data {
 186         /*
 187          * consumer_data.lock protects consumer_data.fd_list,
 188          * consumer_data.stream_count, and consumer_data.need_update. It
 189          * ensures the count matches the number of items in the fd_list.
 190          * It ensures the list updates *always* trigger an fd_array
 191          * update (therefore need to make list update vs
 192          * consumer_data.need_update flag update atomic, and also flag
 193          * read, fd array and flag clear atomic).
 194          */
 195         pthread_mutex_t lock;
 196         /*
 197          * Number of streams in the list below. Protected by
 198          * consumer_data.lock.
 199          */
 200         int stream_count;
 201         /*
 202          * Lists of streams and channels. Protected by consumer_data.lock.
 203          */
 204         struct lttng_consumer_stream_list stream_list;
 205         struct lttng_consumer_channel_list channel_list;
 206         /*
 207          * Flag specifying if the local array of FDs needs update in the
 208          * poll function. Protected by consumer_data.lock.
 209          */
 210         unsigned int need_update;
 211         enum lttng_consumer_type type;
 212 };
 213
 214 /*
 215  * Set the error socket for communication with a session daemon.
 216  */
 217 extern void lttng_consumer_set_error_sock(
 218                 struct lttng_consumer_local_data *ctx, int sock);
 219
 220 /*
 221  * Set the command socket path for communication with a session daemon.
 222  */
 223 extern void lttng_consumer_set_command_sock_path(
 224                 struct lttng_consumer_local_data *ctx, char *sock);
 225
 226 /*
 227  * Send return code to session daemon.
 228  *
 229  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 230  * on error.
 231  */
 232 extern int lttng_consumer_send_error(
 233                 struct lttng_consumer_local_data *ctx, int cmd);
 234
 235 /*
 236  * Called from signal handler to ensure a clean exit.
 237  */
 238 extern void lttng_consumer_should_exit(
 239                 struct lttng_consumer_local_data *ctx);
 240
 241 /*
 242  * Cleanup the daemon's socket on exit.
 243  */
 244 extern void lttng_consumer_cleanup(void);
 245
 246 /*
 247  * Flush pending writes to trace output disk file.
 248  */
 249 extern void lttng_consumer_sync_trace_file(
 250                 struct lttng_consumer_stream *stream, off_t orig_offset);
 251
 252 /*
 253  * Poll on the should_quit pipe and the command socket return -1 on error and
 254  * should exit, 0 if data is available on the command socket
 255  */
 256 extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 257
 258 extern int consumer_update_poll_array(
 259                 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
 260                 struct lttng_consumer_stream **local_consumer_streams);
 261
 262 extern struct lttng_consumer_stream *consumer_allocate_stream(
 263                 int channel_key, int stream_key,
 264                 int shm_fd, int wait_fd,
 265                 enum lttng_consumer_stream_state state,
 266                 uint64_t mmap_len,
 267                 enum lttng_event_output output,
 268                 const char *path_name);
 269 extern int consumer_add_stream(struct lttng_consumer_stream *stream);
 270 extern void consumer_del_stream(struct lttng_consumer_stream *stream);
 271 extern void consumer_change_stream_state(int stream_key,
 272                 enum lttng_consumer_stream_state state);
 273 extern void consumer_del_channel(struct lttng_consumer_channel *channel);
 274 extern struct lttng_consumer_channel *consumer_allocate_channel(
 275                 int channel_key,
 276                 int shm_fd, int wait_fd,
 277                 uint64_t mmap_len,
 278                 uint64_t max_sb_size);
 279 int consumer_add_channel(struct lttng_consumer_channel *channel);
 280
 281 extern struct lttng_consumer_local_data *lttng_consumer_create(
 282                 enum lttng_consumer_type type,
 283                 int (*buffer_ready)(struct lttng_consumer_stream *stream,
 284                         struct lttng_consumer_local_data *ctx),
 285                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 286                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 287                 int (*update_stream)(int sessiond_key, uint32_t state));
 288 extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 289 extern int lttng_consumer_on_read_subbuffer_mmap(
 290                 struct lttng_consumer_local_data *ctx,
 291                 struct lttng_consumer_stream *stream, unsigned long len);
 292 extern int lttng_consumer_on_read_subbuffer_splice(
 293                 struct lttng_consumer_local_data *ctx,
 294                 struct lttng_consumer_stream *stream, unsigned long len);
 295 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 296                 struct lttng_consumer_stream *stream);
 297 extern int lttng_consumer_get_produced_snapshot(
 298                 struct lttng_consumer_local_data *ctx,
 299                 struct lttng_consumer_stream *stream,
 300                 unsigned long *pos);
 301 extern void *lttng_consumer_thread_poll_fds(void *data);
 302 extern void *lttng_consumer_thread_receive_fds(void *data);
 303 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 304                 int sock, struct pollfd *consumer_sockpoll);
 305
 306 int lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 307                 struct lttng_consumer_local_data *ctx);
 308 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 309
 310 #endif /* _LTTNG_CONSUMER_H */