diff --git a/src/shared/ringbuf.c b/src/shared/ringbuf.c
new file mode 100644
index 0000000..223ec5f
--- /dev/null
+++ b/src/shared/ringbuf.c
+/*
+ *
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2012 Intel Corporation. All rights reserved.
+ *
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <sys/param.h>
+
+#include "util.h"
+#include "ringbuf.h"
+
+struct ringbuf {
+ void *buffer;
+ size_t size;
+ size_t in;
+ size_t out;
+ ringbuf_tracing_func_t in_tracing;
+ void *in_data;
+};
+
+#define RINGBUF_RESET 0
+
+static inline unsigned int align_power2(unsigned int u)
+{
+ return 1 << ((sizeof(u) * 8) - __builtin_clz(u - 1));
+}
+
+struct ringbuf *ringbuf_new(size_t size)
+{
+ struct ringbuf *ringbuf;
+ size_t real_size;
+
+ if (size < 2 || size > UINT_MAX)
+ return NULL;
+
+ /* Find the next power of two for size */
+ real_size = align_power2(size);
+
+ ringbuf = new0(struct ringbuf, 1);
+ if (!ringbuf)
+ return NULL;
+
+ ringbuf->buffer = malloc(real_size);
+ if (!ringbuf->buffer) {
+ free(ringbuf);
+ return NULL;
+ }
+
+ ringbuf->size = real_size;
+ ringbuf->in = RINGBUF_RESET;
+ ringbuf->out = RINGBUF_RESET;
+
+ return ringbuf;
+}
+
+void ringbuf_free(struct ringbuf *ringbuf)
+{
+ if (!ringbuf)
+ return;
+
+ free(ringbuf->buffer);
+ free(ringbuf);
+}
+
+bool ringbuf_set_input_tracing(struct ringbuf *ringbuf,
+ ringbuf_tracing_func_t callback, void *user_data)
+{
+ if (!ringbuf)
+ return false;
+
+ ringbuf->in_tracing = callback;
+ ringbuf->in_data = user_data;
+
+ return true;
+}
+
+size_t ringbuf_capacity(struct ringbuf *ringbuf)
+{
+ if (!ringbuf)
+ return 0;
+
+ return ringbuf->size;
+}
+
+size_t ringbuf_len(struct ringbuf *ringbuf)
+{
+ if (!ringbuf)
+ return 0;
+
+ return ringbuf->in - ringbuf->out;
+}
+
+size_t ringbuf_drain(struct ringbuf *ringbuf, size_t count)
+{
+ size_t len;
+
+ if (!ringbuf)
+ return 0;
+
+ len = MIN(count, ringbuf->in - ringbuf->out);
+ if (!len)
+ return 0;
+
+ ringbuf->out += len;
+
+ if (ringbuf->out == ringbuf->in) {
+ ringbuf->in = RINGBUF_RESET;
+ ringbuf->out = RINGBUF_RESET;
+ }
+
+ return len;
+}
+
+void *ringbuf_peek(struct ringbuf *ringbuf, size_t offset, size_t *len_nowrap)
+{
+ if (!ringbuf)
+ return NULL;
+
+ offset = (ringbuf->out + offset) & (ringbuf->size - 1);
+
+ if (len_nowrap) {
+ size_t len = ringbuf->in - ringbuf->out;
+ *len_nowrap = MIN(len, ringbuf->size - offset);
+ }
+
+ return ringbuf->buffer + offset;
+}
+
+ssize_t ringbuf_write(struct ringbuf *ringbuf, int fd)
+{
+ size_t len, offset, end;
+ struct iovec iov[2];
+ ssize_t consumed;
+
+ if (!ringbuf || fd < 0)
+ return -1;
+
+ /* Determine how much data is available */
+ len = ringbuf->in - ringbuf->out;
+ if (!len)
+ return 0;
+
+ /* Grab data from buffer starting at offset until the end */
+ offset = ringbuf->out & (ringbuf->size - 1);
+ end = MIN(len, ringbuf->size - offset);
+
+ iov[0].iov_base = ringbuf->buffer + offset;
+ iov[0].iov_len = end;
+
+ /* Use second vector for remainder from the beginning */
+ iov[1].iov_base = ringbuf->buffer;
+ iov[1].iov_len = len - end;
+
+ consumed = writev(fd, iov, 2);
+ if (consumed < 0)
+ return -1;
+
+ ringbuf->out += consumed;
+
+ if (ringbuf->out == ringbuf->in) {
+ ringbuf->in = RINGBUF_RESET;
+ ringbuf->out = RINGBUF_RESET;
+ }
+
+ return consumed;
+}
+
+size_t ringbuf_avail(struct ringbuf *ringbuf)
+{
+ if (!ringbuf)
+ return 0;
+
+ return ringbuf->size - ringbuf->in + ringbuf->out;
+}
+
+int ringbuf_printf(struct ringbuf *ringbuf, const char *format, ...)
+{
+ va_list ap;
+ int len;
+
+ va_start(ap, format);
+ len = ringbuf_vprintf(ringbuf, format, ap);
+ va_end(ap);
+
+ return len;
+}
+
+int ringbuf_vprintf(struct ringbuf *ringbuf, const char *format, va_list ap)
+{
+ size_t avail, offset, end;
+ char *str;
+ int len;
+
+ if (!ringbuf || !format)
+ return -1;
+
+ /* Determine maximum length available for string */
+ avail = ringbuf->size - ringbuf->in + ringbuf->out;
+ if (!avail)
+ return -1;
+
+ len = vasprintf(&str, format, ap);
+ if (len < 0 || (size_t) len > avail)
+ return -1;
+
+ /* Determine possible length of string before wrapping */
+ offset = ringbuf->in & (ringbuf->size - 1);
+ end = MIN((size_t) len, ringbuf->size - offset);
+ memcpy(ringbuf->buffer + offset, str, end);
+
+ if (ringbuf->in_tracing)
+ ringbuf->in_tracing(ringbuf->buffer + offset, end,
+ ringbuf->in_data);
+
+ if (len - end > 0) {
+ /* Put the remainder of string at the beginning */
+ memcpy(ringbuf->buffer, str + end, len - end);
+
+ if (ringbuf->in_tracing)
+ ringbuf->in_tracing(ringbuf->buffer, len - end,
+ ringbuf->in_data);
+ }
+
+ free(str);
+
+ ringbuf->in += len;
+
+ return len;
+}
+
+ssize_t ringbuf_read(struct ringbuf *ringbuf, int fd)
+{
+ size_t avail, offset, end;
+ struct iovec iov[2];
+ ssize_t consumed;
+
+ if (!ringbuf || fd < 0)
+ return -1;
+
+ /* Determine how much can actually be consumed */
+ avail = ringbuf->size - ringbuf->in + ringbuf->out;
+ if (!avail)
+ return -1;
+
+ /* Determine how much to consume before wrapping */
+ offset = ringbuf->in & (ringbuf->size - 1);
+ end = MIN(avail, ringbuf->size - offset);
+
+ iov[0].iov_base = ringbuf->buffer + offset;
+ iov[0].iov_len = end;
+
+ /* Now put the remainder into the second vector */
+ iov[1].iov_base = ringbuf->buffer;
+ iov[1].iov_len = avail - end;
+
+ consumed = readv(fd, iov, 2);
+ if (consumed < 0)
+ return -1;
+
+ if (ringbuf->in_tracing) {
+ size_t len = MIN((size_t) consumed, end);
+ ringbuf->in_tracing(ringbuf->buffer + offset, len,
+ ringbuf->in_data);
+ if (consumed - len > 0)
+ ringbuf->in_tracing(ringbuf->buffer, consumed - len,
+ ringbuf->in_data);
+ }
+
+ ringbuf->in += consumed;
+
+ return consumed;
+}
diff --git a/src/shared/ringbuf.h b/src/shared/ringbuf.h
new file mode 100644
index 0000000..1a508a4
--- /dev/null
+++ b/src/shared/ringbuf.h
+/*
+ *
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2012 Intel Corporation. All rights reserved.
+ *
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdbool.h>
+
+typedef void (*ringbuf_tracing_func_t)(const void *buf, size_t count,
+ void *user_data);
+
+struct ringbuf;
+
+struct ringbuf *ringbuf_new(size_t size);
+void ringbuf_free(struct ringbuf *ringbuf);
+
+bool ringbuf_set_input_tracing(struct ringbuf *ringbuf,
+ ringbuf_tracing_func_t callback, void *user_data);
+
+size_t ringbuf_capacity(struct ringbuf *ringbuf);
+
+size_t ringbuf_len(struct ringbuf *ringbuf);
+size_t ringbuf_drain(struct ringbuf *ringbuf, size_t count);
+void *ringbuf_peek(struct ringbuf *ringbuf, size_t offset, size_t *len_nowrap);
+ssize_t ringbuf_write(struct ringbuf *ringbuf, int fd);
+
+size_t ringbuf_avail(struct ringbuf *ringbuf);
+int ringbuf_printf(struct ringbuf *ringbuf, const char *format, ...)
+ __attribute__((format(printf, 2, 3)));
+int ringbuf_vprintf(struct ringbuf *ringbuf, const char *format, va_list ap);
+ssize_t ringbuf_read(struct ringbuf *ringbuf, int fd);