diff --git a/include/qb/qbrb.h b/include/qb/qbrb.h
index 88dc8c6..7bb57c1 100644
--- a/include/qb/qbrb.h
+++ b/include/qb/qbrb.h
@@ -114,7 +114,8 @@ typedef struct qb_ringbuffer_s qb_ringbuffer_t;
  * @return a new ring buffer or NULL if there was a problem.
  * @see QB_RB_FLAG_CREATE, QB_RB_FLAG_OVERWRITE, QB_RB_FLAG_SHARED_THREAD, QB_RB_FLAG_SHARED_PROCESS
  */
-qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags);
+qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags,
+			    size_t shared_user_data_size);
 
 /**
  * Dereference the ringbuffer and if we are the last user destroy it.
@@ -133,6 +134,9 @@ void qb_rb_close(qb_ringbuffer_t * rb, int32_t force_it);
  */
 char *qb_rb_name_get(qb_ringbuffer_t * rb);
 
+
+void *qb_rb_shared_user_data_get(qb_ringbuffer_t * rb);
+
 /**
  * Write a chunk to the ring buffer.
  *
diff --git a/lib/ringbuffer.c b/lib/ringbuffer.c
index 319d6df..65e8c57 100644
--- a/lib/ringbuffer.c
+++ b/lib/ringbuffer.c
@@ -82,7 +82,8 @@ static size_t _qb_rb_space_used_locked_(qb_ringbuffer_t * rb);
 static void _qb_rb_chunk_check_locked_(qb_ringbuffer_t * rb, uint32_t pointer);
 static void _qb_rb_chunk_reclaim_locked_(qb_ringbuffer_t * rb);
 
-qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags)
+qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags,
+			    size_t shared_user_data_size)
 {
 	struct qb_ringbuffer_s *rb = malloc(sizeof(struct qb_ringbuffer_s));
 	size_t real_size = QB_ROUNDUP(size, sysconf(_SC_PAGESIZE));
@@ -90,6 +91,8 @@ qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags)
 	int32_t fd_hdr;
 	int32_t fd_data;
 	uint32_t file_flags = O_RDWR;
+	size_t shared_size = sizeof(struct qb_ringbuffer_shared_s);
+	shared_size += shared_user_data_size;
 
 	if (flags & QB_RB_FLAG_CREATE) {
 		file_flags |= O_CREAT | O_TRUNC;
@@ -98,7 +101,7 @@ qb_ringbuffer_t *qb_rb_open(const char *name, size_t size, uint32_t flags)
 	 * Create a shared_hdr memory segment for the header.
 	 */
 	fd_hdr = qb_util_mmap_file_open(path, name,
-					sizeof(struct qb_ringbuffer_shared_s),
+					shared_size,
 					file_flags);
 	if (fd_hdr < 0) {
 		qb_util_log(LOG_ERR, "couldn't create file for mmap");
@@ -230,6 +233,11 @@ char *qb_rb_name_get(qb_ringbuffer_t * rb)
 	return rb->shared_hdr->hdr_path;
 }
 
+void *qb_rb_shared_user_data_get(qb_ringbuffer_t * rb)
+{
+	return rb->shared_hdr->user_data;
+}
+
 static size_t _qb_rb_space_free_locked_(qb_ringbuffer_t * rb)
 {
 	uint32_t write_size;
diff --git a/lib/ringbuffer_int.h b/lib/ringbuffer_int.h
index 917d41c..af94f8c 100644
--- a/lib/ringbuffer_int.h
+++ b/lib/ringbuffer_int.h
@@ -56,6 +56,7 @@ struct qb_ringbuffer_shared_s {
 	int32_t ref_count;
 	sem_t posix_sem;
 	pthread_spinlock_t spinlock;
+	char user_data[1];
 };
 
 struct qb_ringbuffer_s {
diff --git a/tests/check_rb.c b/tests/check_rb.c
index 11c2097..39d70ab 100644
--- a/tests/check_rb.c
+++ b/tests/check_rb.c
@@ -43,7 +43,7 @@ START_TEST(test_ring_buffer1)
 	ssize_t actual;
 	ssize_t avail;
 
-	rb = qb_rb_open("test1", 200, QB_RB_FLAG_CREATE);
+	rb = qb_rb_open("test1", 200, QB_RB_FLAG_CREATE, 0);
 	fail_if(rb == NULL);
 
 	for (b = 0; b < 3; b++) {
@@ -97,7 +97,7 @@ START_TEST(test_ring_buffer2)
 	int64_t *new_data;
 	ssize_t l;
 
-	t = qb_rb_open("test2", 200 * sizeof(int64_t), QB_RB_FLAG_CREATE);
+	t = qb_rb_open("test2", 200 * sizeof(int64_t), QB_RB_FLAG_CREATE, 0);
 	fail_if(t == NULL);
 	for (i = 0; i < 200; i++) {
 		l = qb_rb_chunk_write(t, &v, sizeof(v));
@@ -143,7 +143,7 @@ START_TEST(test_ring_buffer3)
 	ssize_t l;
 	size_t len = strlen(v) + 1;
 
-	t = qb_rb_open("test3", 10, QB_RB_FLAG_CREATE | QB_RB_FLAG_OVERWRITE);
+	t = qb_rb_open("test3", 10, QB_RB_FLAG_CREATE | QB_RB_FLAG_OVERWRITE, 0);
 	fail_if(t == NULL);
 	for (i = 0; i < 9000; i++) {
 		l = qb_rb_chunk_write(t, v, len);
@@ -170,7 +170,7 @@ START_TEST(test_ring_buffer4)
 	char *new_data;
 	ssize_t l;
 
-	t = qb_rb_open("test4", 10, QB_RB_FLAG_CREATE | QB_RB_FLAG_OVERWRITE);
+	t = qb_rb_open("test4", 10, QB_RB_FLAG_CREATE | QB_RB_FLAG_OVERWRITE, 0);
 	fail_if(t == NULL);
 	for (i = 0; i < 2000; i++) {
 		l = qb_rb_chunk_write(t, data, strlen(data));
diff --git a/tests/rbreader.c b/tests/rbreader.c
index a9a5696..816cc3c 100644
--- a/tests/rbreader.c
+++ b/tests/rbreader.c
@@ -37,7 +37,7 @@ int32_t main(int32_t argc, char *argv[])
 	qb_util_set_log_function(libqb_log_writer);
 
 	rb = qb_rb_open("tester", BUFFER_CHUNK_SIZE * 3,
-			QB_RB_FLAG_SHARED_PROCESS | QB_RB_FLAG_CREATE);
+			QB_RB_FLAG_SHARED_PROCESS | QB_RB_FLAG_CREATE, 0);
 
 	if (rb == NULL) {
 		printf("reader: failed to create ringbuffer\n");
diff --git a/tests/rbwriter.c b/tests/rbwriter.c
index 6b69031..56eab1c 100644
--- a/tests/rbwriter.c
+++ b/tests/rbwriter.c
@@ -92,7 +92,7 @@ static void bm_finish(const char *operation, int32_t size)
 static void bmc_connect(void)
 {
 	rb = qb_rb_open("tester", BUFFER_CHUNK_SIZE * 3,
-			QB_RB_FLAG_SHARED_PROCESS);
+			QB_RB_FLAG_SHARED_PROCESS, 0);
 
 	if (rb == NULL) {
 		printf("writer: failed to create ringbuffer\n");