ANDROID: binder: Add BINDER_GET_NODE_DEBUG_INFO ioctl

The BINDER_GET_NODE_DEBUG_INFO ioctl will return debug info on
a node.  Each successive call reusing the previous return value
will return the next node.  The data will be used by
libmemunreachable to mark the pointers with kernel references
as reachable.

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

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 8f2031c..eb8bd8d 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4389,6 +4389,31 @@ out:
 	return ret;
 }
 
+static int binder_ioctl_get_node_debug_info(struct binder_proc *proc,
+				struct binder_node_debug_info *info)
+{
+	struct rb_node *n;
+	binder_uintptr_t ptr = info->ptr;
+
+	memset(info, 0, sizeof(*info));
+
+	binder_inner_proc_lock(proc);
+	for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {
+		struct binder_node *node = rb_entry(n, struct binder_node,
+						    rb_node);
+		if (node->ptr > ptr) {
+			info->ptr = node->ptr;
+			info->cookie = node->cookie;
+			info->has_strong_ref = node->has_strong_ref;
+			info->has_weak_ref = node->has_weak_ref;
+			break;
+		}
+	}
+	binder_inner_proc_unlock(proc);
+
+	return 0;
+}
+
 static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	int ret;
@@ -4458,6 +4483,24 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	}
+	case BINDER_GET_NODE_DEBUG_INFO: {
+		struct binder_node_debug_info info;
+
+		if (copy_from_user(&info, ubuf, sizeof(info))) {
+			ret = -EFAULT;
+			goto err;
+		}
+
+		ret = binder_ioctl_get_node_debug_info(proc, &info);
+		if (ret < 0)
+			goto err;
+
+		if (copy_to_user(ubuf, &info, sizeof(info))) {
+			ret = -EFAULT;
+			goto err;
+		}
+		break;
+	}
 	default:
 		ret = -EINVAL;
 		goto err;