[PATCH wayland] shm: add getters for the fd and offset

[Giulio Camuffo]

This allows to share the buffer data by mmapping the fd again.
---
 src/wayland-server-core.h |  6 ++++++
 src/wayland-shm.c         | 16 +++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/wayland-server-core.h b/src/wayland-server-core.h
index 7d03789..938cdf7 100644
--- a/src/wayland-server-core.h
+++ b/src/wayland-server-core.h
@@ -396,6 +396,12 @@ wl_shm_buffer_create(struct wl_client *client,
 		     uint32_t id, int32_t width, int32_t height,
 		     int32_t stride, uint32_t format);
 
+int
+wl_shm_buffer_get_offset(struct wl_shm_buffer *buffer);
+
+int
+wl_shm_buffer_get_fd(struct wl_shm_buffer *buffer);
+
 void wl_log_set_handler_server(wl_log_func_t handler);
 
 #ifdef  __cplusplus
diff --git a/src/wayland-shm.c b/src/wayland-shm.c
index b6b31d6..c85e839 100644
--- a/src/wayland-shm.c
+++ b/src/wayland-shm.c
@@ -52,6 +52,7 @@ struct wl_shm_pool {
 	int refcount;
 	char *data;
 	int32_t size;
+	int fd;
 };
 
 struct wl_shm_buffer {
@@ -77,6 +78,7 @@ shm_pool_unref(struct wl_shm_pool *pool)
 		return;
 
 	munmap(pool->data, pool->size);
+	close(pool->fd);
 	free(pool);
 }
 
@@ -250,7 +252,7 @@ shm_create_pool(struct wl_client *client, struct wl_resource *resource,
 				       "failed mmap fd %d", fd);
 		goto err_close;
 	}
-	close(fd);
+	pool->fd = fd;
 
 	pool->resource =
 		wl_resource_create(client, &wl_shm_pool_interface, 1, id);
@@ -409,6 +411,18 @@ wl_shm_buffer_get_height(struct wl_shm_buffer *buffer)
 	return buffer->height;
 }
 
+WL_EXPORT int
+wl_shm_buffer_get_offset(struct wl_shm_buffer *buffer)
+{
+	return buffer->offset;
+}
+
+WL_EXPORT int
+wl_shm_buffer_get_fd(struct wl_shm_buffer *buffer)
+{
+	return buffer->pool->fd;
+}
+
 static void
 reraise_sigbus(void)
 {
-- 
2.4.5