1 files changed, 113 insertions, 0 deletions
diff --git a/runtime/transport/relayfs.c b/runtime/transport/relayfs.c
new file mode 100644
index 00000000..181a130e
--- /dev/null
+++ b/runtime/transport/relayfs.c
@@ -0,0 +1,113 @@
+#ifndef _TRANSPORT_RELAYFS_C_ /* -*- linux-c -*- */
+#define _TRANSPORT_RELAYFS_C_
+
+/*
+ * relayfs.c - stp relayfs-related transport functions
+ *
+ * Copyright (C) IBM Corporation, 2005
+ * Copyright (C) Redhat Inc, 2005
+ *
+ * This file is released under the GPL.
+ */
+
+/** @file relayfs.c
+ * @brief Systemtap relayfs-related transport functions
+ */
+
+/** @addtogroup transport Transport Functions
+ * @{
+ */
+
+#include "relayfs.h"
+
+/**
+ *	_stp_subbuf_start - subbuf_start() relayfs callback implementation
+ */
+static int _stp_subbuf_start(struct rchan_buf *buf,
+			     void *subbuf,
+			     unsigned prev_subbuf_idx,
+			     void *prev_subbuf)
+{
+	unsigned padding = buf->padding[prev_subbuf_idx];
+	if (prev_subbuf)
+		*((unsigned *)prev_subbuf) = padding;
+
+	return sizeof(padding); /* reserve space for padding */
+}
+
+/**
+ *	_stp_buf_full - buf_full() relayfs callback implementation
+ */
+static void _stp_buf_full(struct rchan_buf *buf,
+			  unsigned subbuf_idx,
+			  void *subbuf)
+{
+	unsigned padding = buf->padding[subbuf_idx];
+	*((unsigned *)subbuf) = padding;
+}
+
+/* relayfs callback functions */
+static struct rchan_callbacks stp_rchan_callbacks =
+{
+	.subbuf_start = _stp_subbuf_start,
+	.buf_full = _stp_buf_full,
+};
+
+/**
+ *	_stp_relayfs_close - destroys relayfs channel
+ *	@chan: the relayfs channel
+ *	@dir: the directory containing the relayfs files
+ */
+void _stp_relayfs_close(struct rchan *chan, struct dentry *dir)
+{
+	if (!chan)
+		return;
+
+	relay_close(chan);
+	if (dir)
+		relayfs_remove_dir(dir);
+}
+
+/**
+ *	_stp_relayfs_open - create relayfs channel
+ *	@n_subbufs: number of relayfs sub-buffers
+ *	@subbuf_size: size of relayfs sub-buffers
+ *	@pid: daemon pid
+ *	@outdir: receives directory dentry
+ *
+ *	Returns relay channel, NULL on failure
+ *
+ *	Creates relayfs files as /systemtap/pid/cpuX in relayfs root
+ */
+struct rchan *_stp_relayfs_open(unsigned n_subbufs,
+				unsigned subbuf_size,
+				int pid,
+				struct dentry **outdir)
+{
+	char dirname[16];
+	struct rchan *chan;
+	struct dentry* dir = NULL;
+
+	sprintf(dirname, "%d", pid);
+	
+	/* TODO: need to create systemtap dir */
+	dir = relayfs_create_dir(dirname, NULL);
+	if (!dir) {
+		printk("STP: couldn't create relayfs dir %s.\n", dirname);
+		return NULL;
+	}
+
+	chan = relay_open("cpu", dir, subbuf_size,
+			  n_subbufs, 0, &stp_rchan_callbacks);
+	if (!chan) {
+		printk("STP: couldn't create relayfs channel.\n");
+		if (dir)
+			relayfs_remove_dir(dir);
+	}
+
+	*outdir = dir;
+	return chan;
+}
+
+#endif /* _TRANSPORT_RELAYFS_C_ */
+