Add lttng_waiter utils

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

diff --git a/src/common/pipe.c b/src/common/pipe.c
index c8f00141574c3a6f11ce278a4c4a07d9cad1fa46..52ee08a978e5a3a1f9b8ecd45b697b7106956120 100644 (file)
--- a/src/common/pipe.c
+++ b/src/common/pipe.c
@@ -404,3 +404,69 @@ error:
        unlock_write_side(pipe);
        return ret;
 }
+
+/*
+ * Return and release the read end of the pipe.
+ *
+ * This call transfers the ownership of the read fd of the underlying pipe
+ * to the caller if it is still open.
+ *
+ * Returns the fd of the read end of the pipe, or -1 if it was already closed or
+ * released.
+ */
+LTTNG_HIDDEN
+int lttng_pipe_release_readfd(struct lttng_pipe *pipe)
+{
+       int ret;
+
+       if (!pipe) {
+               ret = -1;
+               goto end;
+       }
+
+       lock_read_side(pipe);
+       if (!lttng_pipe_is_read_open(pipe)) {
+               ret = -1;
+               goto end_unlock;
+       }
+       ret = pipe->fd[0];
+       pipe->fd[0] = -1;
+       pipe->r_state = LTTNG_PIPE_STATE_CLOSED;
+end_unlock:
+       unlock_read_side(pipe);
+end:
+       return ret;
+}
+
+/*
+ * Return and release the write end of the pipe.
+ *
+ * This call transfers the ownership of the write fd of the underlying pipe
+ * to the caller if it is still open.
+ *
+ * Returns the fd of the write end of the pipe, or -1 if it was alwritey closed
+ * or released.
+ */
+LTTNG_HIDDEN
+int lttng_pipe_release_writefd(struct lttng_pipe *pipe)
+{
+       int ret;
+
+       if (!pipe) {
+               ret = -1;
+               goto end;
+       }
+
+       lock_write_side(pipe);
+       if (!lttng_pipe_is_write_open(pipe)) {
+               ret = -1;
+               goto end_unlock;
+       }
+       ret = pipe->fd[1];
+       pipe->fd[1] = -1;
+       pipe->w_state = LTTNG_PIPE_STATE_CLOSED;
+end_unlock:
+       unlock_write_side(pipe);
+end:
+       return ret;
+}