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authorMartijn Coenen <maco@android.com>2018-09-07 16:38:37 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-14 16:22:48 +0300
commitb7e6a8961b5d6dd3fc535970e65d497d868bb49f (patch)
tree97e6dda19380e653059e478ba9102963132df713 /drivers/android/binder.c
parent6b6642dadd685af885367d6e30f18553e2a23b22 (diff)
downloadlinux-b7e6a8961b5d6dd3fc535970e65d497d868bb49f.tar.xz
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>
Diffstat (limited to 'drivers/android/binder.c')
-rw-r--r--drivers/android/binder.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 46dad7d724ac..1b54bb57a9fb 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4661,6 +4661,42 @@ out:
return ret;
}
+static int binder_ioctl_get_node_info_for_ref(struct binder_proc *proc,
+ struct binder_node_info_for_ref *info)
+{
+ struct binder_node *node;
+ struct binder_context *context = proc->context;
+ __u32 handle = info->handle;
+
+ if (info->strong_count || info->weak_count || info->reserved1 ||
+ info->reserved2 || info->reserved3) {
+ binder_user_error("%d BINDER_GET_NODE_INFO_FOR_REF: only handle may be non-zero.",
+ proc->pid);
+ return -EINVAL;
+ }
+
+ /* This ioctl may only be used by the context manager */
+ mutex_lock(&context->context_mgr_node_lock);
+ if (!context->binder_context_mgr_node ||
+ context->binder_context_mgr_node->proc != proc) {
+ mutex_unlock(&context->context_mgr_node_lock);
+ return -EPERM;
+ }
+ mutex_unlock(&context->context_mgr_node_lock);
+
+ node = binder_get_node_from_ref(proc, handle, true, NULL);
+ if (!node)
+ return -EINVAL;
+
+ info->strong_count = node->local_strong_refs +
+ node->internal_strong_refs;
+ info->weak_count = node->local_weak_refs;
+
+ binder_put_node(node);
+
+ return 0;
+}
+
static int binder_ioctl_get_node_debug_info(struct binder_proc *proc,
struct binder_node_debug_info *info)
{
@@ -4755,6 +4791,25 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}
break;
}
+ case BINDER_GET_NODE_INFO_FOR_REF: {
+ struct binder_node_info_for_ref info;
+
+ if (copy_from_user(&info, ubuf, sizeof(info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ ret = binder_ioctl_get_node_info_for_ref(proc, &info);
+ if (ret < 0)
+ goto err;
+
+ if (copy_to_user(ubuf, &info, sizeof(info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ break;
+ }
case BINDER_GET_NODE_DEBUG_INFO: {
struct binder_node_debug_info info;