Register the consuming function and add a library context

[lttng-tools.git] / liblttkconsumerd / lttkconsumerd.h

diff --git a/liblttkconsumerd/lttkconsumerd.h b/liblttkconsumerd/lttkconsumerd.h
index cbdedd213ba0c614e3336d91378c780ac26af618..10e4a5504e19148ac7fe69d10783342090019bc4 100644 (file)
--- a/liblttkconsumerd/lttkconsumerd.h
+++ b/liblttkconsumerd/lttkconsumerd.h
@@ -57,15 +57,59 @@ struct kconsumerd_fd {
        unsigned long max_sb_size; /* the subbuffer size for this channel */
 };
 
+struct kconsumerd_local_data {
+       /* function to call when data is available on a buffer */
+       int (*on_buffer_ready)(struct kconsumerd_fd *kconsumerd_fd);
+       /* socket to communicate errors with sessiond */
+       int kconsumerd_error_socket;
+       /* socket to exchange commands with sessiond */
+       char *kconsumerd_command_sock_path;
+       /* communication with splice */
+       int kconsumerd_thread_pipe[2];
+       /* pipe to wake the poll thread when necessary */
+       int kconsumerd_poll_pipe[2];
+       /* to let the signal handler wake up the fd receiver thread */
+       int kconsumerd_should_quit[2];
+};
+
 /*
- * kconsumerd_init(void)
+ * kconsumerd_create
  * initialise the necessary environnement :
- * - inform the polling thread to update the polling array
+ * - create a new context
  * - create the poll_pipe
  * - create the should_quit pipe (for signal handler)
- * returns the return code of pipe, 0 on success, -1 on error
+ * - create the thread pipe (for splice)
+ * Takes a function pointer as argument, this function is called when data is
+ * available on a buffer. This function is responsible to do the
+ * kernctl_get_next_subbuf, read the data with mmap or splice depending on the
+ * buffer configuration and then kernctl_put_next_subbuf at the end.
+ * Returns a pointer to the new context or NULL on error.
+ */
+struct kconsumerd_local_data *kconsumerd_create(
+               int (*buffer_ready)(struct kconsumerd_fd *kconsumerd_fd));
+
+/*
+ * kconsumerd_destroy
+ * Close all fds associated with the instance and free the context
+ */
+void kconsumerd_destroy(struct kconsumerd_local_data *ctx);
+
+/*
+ * kconsumerd_on_read_subbuffer_mmap
+ * mmap the ring buffer, read it and write the data to the tracefile.
+ * Returns the number of bytes written
+ */
+int kconsumerd_on_read_subbuffer_mmap(struct kconsumerd_local_data *ctx,
+               struct kconsumerd_fd *kconsumerd_fd, unsigned long len);
+
+/*
+ * kconsumerd_on_read_subbuffer
+ *
+ * Splice the data from the ring buffer to the tracefile.
+ * Returns the number of bytes spliced
  */
-int kconsumerd_init(void);
+int kconsumerd_on_read_subbuffer_splice(struct kconsumerd_local_data *ctx,
+               struct kconsumerd_fd *kconsumerd_fd, unsigned long len);
 
 /*
  * kconsumerd_send_error
@@ -73,7 +117,8 @@ int kconsumerd_init(void);
  * returns the return code of sendmsg : the number of bytes transmitted
  * or -1 on error.
  */
-int kconsumerd_send_error(enum lttcomm_return_code cmd);
+int kconsumerd_send_error(struct kconsumerd_local_data *ctx,
+               enum lttcomm_return_code cmd);
 
 /*
  * kconsumerd_poll_socket
@@ -101,7 +146,7 @@ void *kconsumerd_thread_receive_fds(void *data);
  * kconsumerd_should_exit
  * Called from signal handler to ensure a clean exit
  */
-void kconsumerd_should_exit(void);
+void kconsumerd_should_exit(struct kconsumerd_local_data *ctx);
 
 /*
  *  kconsumerd_cleanup
@@ -113,12 +158,12 @@ void kconsumerd_cleanup(void);
  * kconsumerd_set_error_socket
  * Set the error socket for communication with a session daemon
  */
-void kconsumerd_set_error_socket(int sock);
+void kconsumerd_set_error_socket(struct kconsumerd_local_data *ctx, int sock);
 
 /*
  * kconsumerd_set_command_socket_path
  * Set the command socket path for communication with a session daemon
  */
-void kconsumerd_set_command_socket_path(char *sock);
+void kconsumerd_set_command_socket_path(struct kconsumerd_local_data *ctx, char *sock);
 
 #endif /* _LIBLTTKCONSUMERD_H */