Add wrappers for pipe

[lttng-tools.git] / src / common / pipe.h

diff --git a/src/common/pipe.h b/src/common/pipe.h
new file mode 100644 (file)
index 0000000..11f41cf
--- /dev/null
+++ b/src/common/pipe.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * 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., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef LTTNG_PIPE_H
+#define LTTNG_PIPE_H
+
+#include <pthread.h>
+
+enum lttng_pipe_state {
+       LTTNG_PIPE_STATE_OPENED = 1,
+       LTTNG_PIPE_STATE_CLOSED = 2,
+};
+
+struct lttng_pipe {
+       /* Read: 0, Write: 1. */
+       int fd[2];
+       /*
+        * Flags of the pipe once opened. pipe(2) specifies either O_NONBLOCK or
+        * O_CLOEXEC can be used. Flags are set using fcntl(2) call.
+        */
+       int flags;
+
+       /*
+        * These states are protected by the operation mutex below.
+        */
+       enum lttng_pipe_state r_state;
+       enum lttng_pipe_state w_state;
+
+       /* Held for each read(2) operation. */
+       pthread_mutex_t read_mutex;
+       /* Held for each write(2) operation. */
+       pthread_mutex_t write_mutex;
+};
+
+/*
+ * Return 1 if read side is open else 0.
+ */
+static inline int lttng_pipe_is_read_open(struct lttng_pipe *pipe)
+{
+       return pipe->r_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
+}
+
+/*
+ * Return 1 if write side is open else 0.
+ */
+static inline int lttng_pipe_is_write_open(struct lttng_pipe *pipe)
+{
+       return pipe->w_state == LTTNG_PIPE_STATE_OPENED ? 1 : 0;
+}
+
+static inline int lttng_pipe_get_readfd(struct lttng_pipe *pipe)
+{
+       return pipe->fd[0];
+}
+
+static inline int lttng_pipe_get_writefd(struct lttng_pipe *pipe)
+{
+       return pipe->fd[1];
+}
+
+struct lttng_pipe *lttng_pipe_open(int flags);
+int lttng_pipe_write_close(struct lttng_pipe *pipe);
+int lttng_pipe_read_close(struct lttng_pipe *pipe);
+/* Close both side of pipe. */
+int lttng_pipe_close(struct lttng_pipe *pipe);
+void lttng_pipe_destroy(struct lttng_pipe *pipe);
+
+ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count);
+ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf,
+               size_t count);
+
+#endif /* LTTNG_PIPE_H */