From 726a0206326ca4cf22aa7c59e174a83a0da9727f Mon Sep 17 00:00:00 2001 From: Ethan Yonker Date: Tue, 16 Dec 2014 20:01:38 -0600 Subject: MTP add/remove storage instead of disabling MTP Implement a pipe between TWRP and MTP to allow TWRP to tell MTP to remove storage partitions as they become unavailable (e.g. during a wipe, unmount, etc) instead of disabling MTP completely. This includes some fixes and improvements in destructors to properly remove / delete various items. This also means that we will not be toggling adb off and on quite as often. I do not like that we had to add another thread, but we were unable to use select() on the mtp_usb character device because this device does not support polling. Select always returned indicating that the mtp file descriptor was ready to be read and the resulting read would block. The read block prevented us from being able to include reading of the pipe between TWRP and MTP in the main MTP thread. We might want to add a return pipe letting TWRP know if the removal of the storage device was successful, but I am not sure how we want to implement this. It would invovle timeouts in both TWRP and MTP to ensure that we returned a failure indicator in a timely manner to TWRP and prevent deleting the storage device in the case of a failure. Right now we make no attempt to ensure that an MTP operation is underway like a large file transfer, but we were not doing anything like this in the past. In some respects we have limited control over what happens. If the user installs a zip that unmounts a storage partition, we will not know about the change in storage status anyway. Regular Android does not have these troubles because partitions rarely get unmounted like in recovery. At some point, we have to hold the user accountable for performing actions that may remove a storage partition while they are using MTP anyway. Ideally we do not want to toggle the USB IDs and thus toggle adb off and on during early boot, but I am not sure what the best way to handle that at this time. Change-Id: I9343e5396bf6023d3b994de1bf01ed91d129bc14 --- mtp/MtpMessage.hpp | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 mtp/MtpMessage.hpp (limited to 'mtp/MtpMessage.hpp') diff --git a/mtp/MtpMessage.hpp b/mtp/MtpMessage.hpp new file mode 100644 index 000000000..272da1743 --- /dev/null +++ b/mtp/MtpMessage.hpp @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * Copyright (C) 2014 TeamWin - bigbiff and Dees_Troy mtp database conversion to C++ + */ + +#ifndef _MTPMESSAGE_HPP +#define _MTPMESSAGE_HPP + +#define MTP_MESSAGE_ADD_STORAGE 1 +#define MTP_MESSAGE_REMOVE_STORAGE 2 + +struct mtpmsg { + int message_type; // 1 is add, 2 is remove, see above + unsigned int storage_id; + const char* display; + const char* path; + uint64_t maxFileSize; +}; + +#endif //_MTPMESSAGE_HPP -- cgit v1.2.3