Create a library for the kernel consumer

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

diff --git a/liblttkconsumerd/liblttkconsumerd.h b/liblttkconsumerd/liblttkconsumerd.h
new file mode 100644 (file)
index 0000000..8dc6b62
--- /dev/null
+++ b/liblttkconsumerd/liblttkconsumerd.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef _LIBLTTKCONSUMERD_H
+#define _LIBLTTKCONSUMERD_H
+
+#include "lttng-kconsumerd.h"
+#include "liblttsessiondcomm.h"
+
+/*
+ * When the receiving thread dies, we need to have a way to make
+ * the polling thread exit eventually.
+ * If all FDs hang up (normal case when the ltt-sessiond stops),
+ * we can exit cleanly, but if there is a problem and for whatever
+ * reason some FDs remain open, the consumer should still exit eventually.
+ *
+ * If the timeout is reached, it means that during this period
+ * no events occurred on the FDs so we need to force an exit.
+ * This case should not happen but it is a safety to ensure we won't block
+ * the consumer indefinitely.
+ *
+ * The value of 2 seconds is an arbitrary choice.
+ */
+#define KCONSUMERD_POLL_GRACE_PERIOD 2000
+
+struct kconsumerd_fd_list {
+       struct cds_list_head head;
+};
+
+/*
+ * Internal representation of the FDs,
+ * sessiond_fd is used to identify uniquely a fd
+ */
+struct kconsumerd_fd {
+       struct cds_list_head list;
+       int sessiond_fd; /* used to identify uniquely a fd with sessiond */
+       int consumerd_fd; /* fd to consume */
+       int out_fd; /* output file to write the data */
+       off_t out_fd_offset; /* write position in the output file descriptor */
+       char path_name[PATH_MAX]; /* tracefile name */
+       enum kconsumerd_fd_state state;
+       unsigned long max_sb_size; /* the subbuffer size for this channel */
+};
+
+int kconsumerd_create_poll_pipe();
+int kconsumerd_send_error(enum lttcomm_return_code cmd);
+void *kconsumerd_thread_poll_fds(void *data);
+void *kconsumerd_thread_receive_fds(void *data);
+void kconsumerd_cleanup();
+void kconsumerd_set_error_socket(int sock);
+void kconsumerd_set_command_socket_path(char *sock);
+
+#endif /* _LIBLTTKCONSUMERD_H */