binder: Add BINDER_GET_NODE_INFO_FOR_REF ioctl.

This allows the context manager to retrieve information about nodes
that it holds a reference to, such as the current number of
references to those nodes.

Such information can for example be used to determine whether the
servicemanager is the only process holding a reference to a node.
This information can then be passed on to the process holding the
node, which can in turn decide whether it wants to shut down to
reduce resource usage.

Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index bfaec6903b8b..b9ba520f7e4b 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -200,6 +200,15 @@ struct binder_node_debug_info {
         __u32            has_weak_ref;
 };
 
+struct binder_node_info_for_ref {
+        __u32            handle;
+        __u32            strong_count;
+        __u32            weak_count;
+        __u32            reserved1;
+        __u32            reserved2;
+        __u32            reserved3;
+};
+
 #define BINDER_WRITE_READ               _IOWR('b', 1, struct binder_write_read)
 #define BINDER_SET_IDLE_TIMEOUT         _IOW('b', 3, __s64)
 #define BINDER_SET_MAX_THREADS          _IOW('b', 5, __u32)
@@ -208,6 +217,7 @@ struct binder_node_debug_info {
 #define BINDER_THREAD_EXIT              _IOW('b', 8, __s32)
 #define BINDER_VERSION                  _IOWR('b', 9, struct binder_version)
 #define BINDER_GET_NODE_DEBUG_INFO      _IOWR('b', 11, struct binder_node_debug_info)
+#define BINDER_GET_NODE_INFO_FOR_REF    _IOWR('b', 12, struct binder_node_info_for_ref)
 
 /*
  * NOTE: Two special error codes you should check for when calling