diff options
author | Martijn Coenen <maco@android.com> | 2018-09-07 16:38:37 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-14 16:22:48 +0300 |
commit | b7e6a8961b5d6dd3fc535970e65d497d868bb49f (patch) | |
tree | 97e6dda19380e653059e478ba9102963132df713 /drivers/android/binder.c | |
parent | 6b6642dadd685af885367d6e30f18553e2a23b22 (diff) | |
download | linux-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.c | 55 |
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; |