/*
 * Copyright 2003-2017, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Ingo Weinhold, ingo_weinhold@gmx.de
 *              Axel Dörfler, axeld@pinc-software.de
 */

/*! \file ddm_userland_interface.cpp

        \brief Interface for userspace calls.
*/

#include <ddm_userland_interface.h>

#include <stdlib.h>

#include <AutoDeleter.h>
#include <fs/KPath.h>
#include <KDiskDevice.h>
#include <KDiskDeviceManager.h>
#include <KDiskDeviceUtils.h>
#include <KDiskSystem.h>
#include <KFileDiskDevice.h>
#include <syscall_args.h>

#include "UserDataWriter.h"

using namespace BPrivate::DiskDevice;

// debugging
#define ERROR(x)


// TODO: Replace all instances, when it has been decided how to handle
// notifications during jobs.
#define DUMMY_JOB_ID    0


/*! \brief Wrapper around user_strlcpy() that returns a status_t
        indicating appropriate success or failure.

        \param allowTruncation If \c true, does not return an error if
               \a from is longer than \to. If \c false, returns \c B_NAME_TOO_LONG
               if \a from is longer than \to.
*/
static status_t
ddm_strlcpy(char *to, const char *from, size_t size,
        bool allowTruncation = false)
{
        ssize_t fromLen = user_strlcpy(to, from, size);
        if (fromLen < 0)
                return fromLen;
        if ((size_t)fromLen >= size && !allowTruncation)
                return B_NAME_TOO_LONG;
        return B_OK;
}


template<typename Type>
static inline status_t
copy_from_user_value(Type& value, const Type* userValue)
{
        if (userValue == NULL)
                return B_BAD_VALUE;

        if (!IS_USER_ADDRESS(userValue))
                return B_BAD_ADDRESS;

        return user_memcpy(&value, userValue, sizeof(Type));
}


template<typename Type>
static inline status_t
copy_to_user_value(Type* userValue, const Type& value)
{
        if (userValue == NULL)
                return B_BAD_VALUE;

        if (!IS_USER_ADDRESS(userValue))
                return B_BAD_ADDRESS;

        return user_memcpy(userValue, &value, sizeof(Type));
}


template<bool kAllowsNull>
struct UserStringParameter {
        char*   value;

        inline UserStringParameter()
                : value(NULL)
        {
        }

        inline ~UserStringParameter()
        {
                free(value);
        }

        inline status_t Init(const char* userValue, size_t maxSize)
        {
                if (userValue == NULL) {
                        if (!kAllowsNull)
                                return B_BAD_VALUE;

                        return B_OK;
                }

                if (!IS_USER_ADDRESS(userValue))
                        return B_BAD_ADDRESS;

                value = (char*)malloc(maxSize);
                if (value == NULL)
                        return B_NO_MEMORY;

                ssize_t bytesCopied = user_strlcpy(value, userValue, maxSize);
                if (bytesCopied < 0)
                        return bytesCopied;

                if ((size_t)bytesCopied >= maxSize)
                        return B_BUFFER_OVERFLOW;

                return B_OK;
        }

        inline operator const char*()
        {
                return value;
        }

        inline operator char*()
        {
                return value;
        }
};


#if 0
static void
move_descendants(KPartition *partition, off_t moveBy)
{
        if (!partition)
                return;
        partition->SetOffset(partition->Offset() + moveBy);
        // move children
        for (int32 i = 0; KPartition *child = partition->ChildAt(i); i++)
                move_descendants(child, moveBy);
}


static status_t
move_descendants_contents(KPartition *partition)
{
        if (!partition)
                return B_BAD_VALUE;
        // implicit content disk system changes
        KDiskSystem *diskSystem = partition->DiskSystem();
        if (diskSystem || partition->AlgorithmData()) {
                status_t error = diskSystem->ShadowPartitionChanged(partition,
                        NULL, B_PARTITION_MOVE);
                if (error != B_OK)
                        return error;
        }
        // move children's contents
        for (int32 i = 0; KPartition *child = partition->ChildAt(i); i++) {
                status_t error = move_descendants_contents(child);
                if (error != B_OK)
                        return error;
        }
        return B_OK;
}
#endif // 0


partition_id
_user_get_next_disk_device_id(int32 *_cookie, size_t *neededSize)
{
        int32 cookie;
        status_t error = copy_from_user_value(cookie, _cookie);
        if (error != B_OK)
                return error;

        partition_id id = B_ENTRY_NOT_FOUND;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // get the next device
        if (KDiskDevice *device = manager->RegisterNextDevice(&cookie)) {
                PartitionRegistrar _(device, true);
                id = device->ID();
                if (neededSize != NULL) {
                        if (DeviceReadLocker locker = device) {
                                // get the needed size
                                UserDataWriter writer;
                                device->WriteUserData(writer);
                                status_t status = copy_to_user_value(neededSize,
                                        writer.AllocatedSize());
                                if (status != B_OK)
                                        return status;
                        } else
                                id = B_ERROR;
                }
        }

        error = copy_to_user_value(_cookie, cookie);
        if (error != B_OK)
                return error;
        return id;
}


partition_id
_user_find_disk_device(const char *_filename, size_t *neededSize)
{
        UserStringParameter<false> filename;
        status_t error = filename.Init(_filename, B_PATH_NAME_LENGTH);
        if (error != B_OK)
                return error;

        partition_id id = B_ENTRY_NOT_FOUND;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // find the device
        if (KDiskDevice *device = manager->RegisterDevice(filename)) {
                PartitionRegistrar _(device, true);
                id = device->ID();
                if (neededSize != NULL) {
                        if (DeviceReadLocker locker = device) {
                                // get the needed size
                                UserDataWriter writer;
                                device->WriteUserData(writer);
                                error = copy_to_user_value(neededSize, writer.AllocatedSize());
                                if (error != B_OK)
                                        return error;
                        } else
                                return B_ERROR;
                }
        }
        return id;
}


partition_id
_user_find_partition(const char *_filename, size_t *neededSize)
{
        UserStringParameter<false> filename;
        status_t error = filename.Init(_filename, B_PATH_NAME_LENGTH);
        if (error != B_OK)
                return error;

        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // find the partition
        KPartition *partition = manager->RegisterPartition(filename);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;
        PartitionRegistrar _(partition, true);
        partition_id id = partition->ID();
        if (neededSize != NULL) {
                // get and lock the partition's device
                KDiskDevice *device = manager->RegisterDevice(partition->ID(), false);
                if (device == NULL)
                        return B_ENTRY_NOT_FOUND;
                PartitionRegistrar _2(device, true);
                if (DeviceReadLocker locker = device) {
                        // get the needed size
                        UserDataWriter writer;
                        device->WriteUserData(writer);
                        error = copy_to_user_value(neededSize, writer.AllocatedSize());
                        if (error != B_OK)
                                return error;
                } else
                        return B_ERROR;
        }
        return id;
}


partition_id
_user_find_file_disk_device(const char *_filename, size_t *neededSize)
{
        UserStringParameter<false> filename;
        status_t error = filename.Init(_filename, B_PATH_NAME_LENGTH);
        if (error != B_OK)
                return error;

        KPath path(filename, KPath::NORMALIZE);

        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // find the device
        KFileDiskDevice* device = manager->RegisterFileDevice(path.Path());
        if (device == NULL)
                return B_ENTRY_NOT_FOUND;
        PartitionRegistrar _(device, true);
        partition_id id = device->ID();
        if (neededSize != NULL) {
                if (DeviceReadLocker locker = device) {
                        // get the needed size
                        UserDataWriter writer;
                        device->WriteUserData(writer);
                        error = copy_to_user_value(neededSize, writer.AllocatedSize());
                        if (error != B_OK)
                                return error;
                } else
                        return B_ERROR;
        }
        return id;
}


/*!     \brief Writes data describing the disk device identified by ID and all
                   its partitions into the supplied buffer.

        The function passes the buffer size required to hold the data back
        through the \a _neededSize parameter, if the device could be found at
        least and no serious error occured. If fails with \c B_BUFFER_OVERFLOW,
        if the supplied buffer is too small or a \c NULL buffer is supplied
        (and \c bufferSize is 0).

        The device is identified by \a id. If \a deviceOnly is \c true, then
        it must be the ID of a disk device, otherwise the disk device is
        chosen, on which the partition \a id refers to resides.

        \param id The ID of an arbitrary partition on the disk device (including
                   the disk device itself), whose data shall be returned
                   (if \a deviceOnly is \c false), or the ID of the disk device
                   itself (if \a deviceOnly is true).
        \param deviceOnly Specifies whether only IDs of disk devices (\c true),
                   or also IDs of partitions (\c false) are accepted for \a id.
        \param buffer The buffer into which the disk device data shall be written.
                   May be \c NULL.
        \param bufferSize The size of \a buffer.
        \param _neededSize Pointer to a variable into which the actually needed
                   buffer size is written. May be \c NULL.
        \return
        - \c B_OK: Everything went fine. The device was found and, if not \c NULL,
          in \a _neededSize the actually needed buffer size is returned. And
          \a buffer will contain the disk device data.
        - \c B_BAD_VALUE: \c NULL \a buffer, but not 0 \a bufferSize.
        - \c B_BUFFER_OVERFLOW: The supplied buffer was too small. \a _neededSize,
          if not \c NULL, will contain the required buffer size.
        - \c B_NO_MEMORY: Insufficient memory to complete the operation.
        - \c B_ENTRY_NOT_FOUND: \a id is no valid disk device ID (if \a deviceOnly
          is \c true) or not even a valid partition ID (if \a deviceOnly is
          \c false).
        - \c B_ERROR: An unexpected error occured.
        - another error code...
*/
status_t
_user_get_disk_device_data(partition_id id, bool deviceOnly,
        user_disk_device_data *buffer, size_t bufferSize, size_t *_neededSize)
{
        if (buffer == NULL && bufferSize > 0)
                return B_BAD_VALUE;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // get the device
        KDiskDevice *device = manager->RegisterDevice(id, deviceOnly);
        if (device == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar _(device, true);
        if (DeviceReadLocker locker = device) {
                // do a dry run first to get the needed size
                UserDataWriter writer;
                device->WriteUserData(writer);
                size_t neededSize = writer.AllocatedSize();
                if (_neededSize != NULL) {
                        status_t error = copy_ref_var_to_user(neededSize, _neededSize);
                        if (error != B_OK)
                                return error;
                }
                // if no buffer has been supplied or the buffer is too small,
                // then we're done
                if (buffer == NULL || bufferSize < neededSize)
                        return B_BUFFER_OVERFLOW;
                if (!IS_USER_ADDRESS(buffer))
                        return B_BAD_ADDRESS;
                // otherwise allocate a kernel buffer
                user_disk_device_data *kernelBuffer
                        = static_cast<user_disk_device_data*>(malloc(neededSize));
                if (kernelBuffer == NULL)
                        return B_NO_MEMORY;
                MemoryDeleter deleter(kernelBuffer);
                // write the device data into the buffer
                writer.SetTo(kernelBuffer, bufferSize);
                device->WriteUserData(writer);
                // sanity check
                if (writer.AllocatedSize() != neededSize) {
                        ERROR(("Size of written disk device user data changed from "
                                   "%lu to %lu while device was locked!\n"));
                        return B_ERROR;
                }
                // relocate
                status_t error = writer.Relocate(buffer);
                if (error != B_OK)
                        return error;
                // copy out
                return user_memcpy(buffer, kernelBuffer, neededSize);
        } else
                return B_ERROR;
}


partition_id
_user_register_file_device(const char *_filename)
{
        UserStringParameter<false> filename;
        status_t error = filename.Init(_filename, B_PATH_NAME_LENGTH);
        if (error != B_OK)
                return error;

        KPath path(filename, KPath::NORMALIZE);

        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        if (ManagerLocker locker = manager) {
                KFileDiskDevice *device = manager->FindFileDevice(path.Path());
                if (device != NULL)
                        return device->ID();
                return manager->CreateFileDevice(path.Path());
        }
        return B_ERROR;
}


status_t
_user_unregister_file_device(partition_id deviceID, const char *_filename)
{
        if (deviceID < 0 && _filename == NULL)
                return B_BAD_VALUE;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        if (deviceID >= 0)
                return manager->DeleteFileDevice(deviceID);

        UserStringParameter<false> filename;
        status_t error = filename.Init(_filename, B_PATH_NAME_LENGTH);
        if (error != B_OK)
                return error;

        return manager->DeleteFileDevice(filename);
}


status_t
_user_get_file_disk_device_path(partition_id id, char* buffer,
        size_t bufferSize)
{
        if (id < 0 || buffer == NULL || bufferSize == 0)
                return B_BAD_VALUE;
        if (!IS_USER_ADDRESS(buffer))
                return B_BAD_ADDRESS;

        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        KDiskDevice *device = manager->RegisterDevice(id, true);
        if (device != NULL) {
                PartitionRegistrar _(device, true);
                if (DeviceReadLocker locker = device) {
                        KFileDiskDevice* fileDevice
                                = dynamic_cast<KFileDiskDevice*>(device);
                        if (fileDevice == NULL)
                                return B_BAD_VALUE;

                        ssize_t copied = user_strlcpy(buffer, fileDevice->FilePath(),
                                bufferSize);
                        if (copied < 0)
                                return copied;
                        return (size_t)copied < bufferSize ? B_OK : B_BUFFER_OVERFLOW;
                }
        }

        return B_ERROR;
}


status_t
_user_get_disk_system_info(disk_system_id id, user_disk_system_info *_info)
{
        if (_info == NULL)
                return B_BAD_VALUE;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        if (ManagerLocker locker = manager) {
                KDiskSystem *diskSystem = manager->FindDiskSystem(id);
                if (diskSystem != NULL) {
                        user_disk_system_info info;
                        diskSystem->GetInfo(&info);
                        return copy_to_user_value(_info, info);
                }
        }
        return B_ENTRY_NOT_FOUND;
}


status_t
_user_get_next_disk_system_info(int32 *_cookie, user_disk_system_info *_info)
{
        if (_info == NULL)
                return B_BAD_VALUE;
        if (!IS_USER_ADDRESS(_info))
                return B_BAD_ADDRESS;
        int32 cookie;
        status_t result = copy_from_user_value(cookie, _cookie);
        if (result != B_OK)
                return result;
        result = B_ENTRY_NOT_FOUND;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        if (ManagerLocker locker = manager) {
                KDiskSystem *diskSystem = manager->NextDiskSystem(&cookie);
                if (diskSystem != NULL) {
                        user_disk_system_info info;
                        diskSystem->GetInfo(&info);
                        result = copy_to_user_value(_info, info);
                }
        }
        status_t error = copy_to_user_value(_cookie, cookie);
        if (error != B_OK)
                result = error;
        return result;
}


status_t
_user_find_disk_system(const char *_name, user_disk_system_info *_info)
{
        if (_name == NULL || _info == NULL)
                return B_BAD_VALUE;
        if (!IS_USER_ADDRESS(_name) || !IS_USER_ADDRESS(_info))
                return B_BAD_ADDRESS;
        char name[B_DISK_SYSTEM_NAME_LENGTH];
        status_t error = ddm_strlcpy(name, _name, B_DISK_SYSTEM_NAME_LENGTH);
        if (error != B_OK)
                return error;
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        if (ManagerLocker locker = manager) {
                KDiskSystem *diskSystem = manager->FindDiskSystem(name);
                if (diskSystem != NULL) {
                        user_disk_system_info info;
                        diskSystem->GetInfo(&info);
                        return copy_to_user_value(_info, info);
                }
        }
        return B_ENTRY_NOT_FOUND;
}


status_t
_user_defragment_partition(partition_id partitionID, int32* _changeCounter)
{
        // copy parameters in
        int32 changeCounter;

        status_t error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(false))
                return B_BUSY;
        locker.Unlock();

        // defragment
        error = diskSystem->Defragment(partition, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(false);

        if (error != B_OK)
                return error;

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_repair_partition(partition_id partitionID, int32* _changeCounter,
        bool checkOnly)
{
        // copy parameters in
        int32 changeCounter;

        status_t error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(false))
                return B_BUSY;
        locker.Unlock();

        // repair/check
        error = diskSystem->Repair(partition, checkOnly, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(false);

        if (error != B_OK)
                return error;

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_resize_partition(partition_id partitionID, int32* _changeCounter,
        partition_id childID, int32* _childChangeCounter, off_t size,
        off_t contentSize)
{
        // copy parameters in
        int32 changeCounter;
        int32 childChangeCounter;

        status_t error = copy_from_user_value(changeCounter, _changeCounter);
        if (error == B_OK)
                error = copy_from_user_value(childChangeCounter, _childChangeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register child
        KPartition* child = manager->RegisterPartition(childID);
        if (child == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar3(child, true);

        // check change counters
        if (changeCounter != partition->ChangeCounter()
                || childChangeCounter != child->ChangeCounter()) {
                return B_BAD_VALUE;
        }

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // child must indeed be a child of partition
        if (child->Parent() != partition)
                return B_BAD_VALUE;

        // check sizes
        if (size < 0 || contentSize < 0 || size < contentSize
                || size > partition->ContentSize()) {
                return B_BAD_VALUE;
        }

        // mark the partitions busy and unlock
        if (partition->IsBusy() || child->IsBusy())
                return B_BUSY;
        partition->SetBusy(true);
        child->SetBusy(true);
        locker.Unlock();

        // resize contents first, if shrinking
        if (child->DiskSystem() && contentSize < child->ContentSize())
                error = child->DiskSystem()->Resize(child, contentSize, DUMMY_JOB_ID);

        // resize the partition
        if (error == B_OK && size != child->Size())
                error = diskSystem->ResizeChild(child, size, DUMMY_JOB_ID);

        // resize contents last, if growing
        if (error == B_OK && child->DiskSystem()
                && contentSize > child->ContentSize()) {
                error = child->DiskSystem()->Resize(child, contentSize, DUMMY_JOB_ID);
        }

        // re-lock and unmark busy
        locker.Lock();
        partition->SetBusy(false);
        child->SetBusy(false);

        if (error != B_OK)
                return error;

        // return change counters
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (error == B_OK)
                error = copy_to_user_value(_childChangeCounter, child->ChangeCounter());
        return error;
}


status_t
_user_move_partition(partition_id partitionID, int32* changeCounter,
        partition_id childID, int32* childChangeCounter, off_t newOffset,
        partition_id* descendantIDs, int32* descendantChangeCounters,
        int32 descendantCount)
{
#if 0
        KDiskDeviceManager *manager = KDiskDeviceManager::Default();
        // get the partition
        KPartition *partition = manager->WriteLockPartition(partitionID);
        if (!partition)
                return B_ENTRY_NOT_FOUND;
        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);
        // check the new offset
        if (newOffset == partition->Offset())
                return B_OK;
        off_t proposedOffset = newOffset;
        status_t error = validate_move_partition(partition, changeCounter,
                &proposedOffset, true);
        if (error != B_OK)
                return error;
        if (proposedOffset != newOffset)
                return B_BAD_VALUE;
        // new offset is fine -- move the thing
        off_t moveBy = newOffset - partition->Offset();
        move_descendants(partition, moveBy);
        partition->Changed(B_PARTITION_CHANGED_OFFSET);
        // implicit partitioning system changes
        error = partition->Parent()->DiskSystem()->ShadowPartitionChanged(
                partition->Parent(), partition, B_PARTITION_MOVE_CHILD);
        if (error != B_OK)
                return error;
        // implicit descendants' content disk system changes
        return move_descendants_contents(partition);
#endif
return B_BAD_VALUE;
}


status_t
_user_set_partition_name(partition_id partitionID, int32* _changeCounter,
        partition_id childID, int32* _childChangeCounter, const char* _name)
{
        // copy parameters in
        UserStringParameter<false> name;
        int32 changeCounter;
        int32 childChangeCounter;

        status_t error = name.Init(_name, B_DISK_DEVICE_NAME_LENGTH);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error == B_OK)
                error = copy_from_user_value(childChangeCounter, _childChangeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register child
        KPartition* child = manager->RegisterPartition(childID);
        if (child == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar3(child, true);

        // check change counters
        if (changeCounter != partition->ChangeCounter()
                || childChangeCounter != child->ChangeCounter()) {
                return B_BAD_VALUE;
        }

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // child must indeed be a child of partition
        if (child->Parent() != partition)
                return B_BAD_VALUE;

        // mark the partitions busy and unlock
        if (partition->IsBusy() || child->IsBusy())
                return B_BUSY;
        partition->SetBusy(true);
        child->SetBusy(true);
        locker.Unlock();

        // set the child name
        error = diskSystem->SetName(child, name.value, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->SetBusy(false);
        child->SetBusy(false);

        if (error != B_OK)
                return error;

        // return change counters
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (error == B_OK)
                error = copy_to_user_value(_childChangeCounter, child->ChangeCounter());
        return error;
}


status_t
_user_set_partition_content_name(partition_id partitionID,
        int32* _changeCounter, const char* _name)
{
        // copy parameters in
        UserStringParameter<true> name;
        int32 changeCounter;

        status_t error = name.Init(_name, B_DISK_DEVICE_NAME_LENGTH);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(false))
                return B_BUSY;
        locker.Unlock();

        // set content parameters
        error = diskSystem->SetContentName(partition, name.value, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(false);

        if (error != B_OK)
                return error;

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_set_partition_type(partition_id partitionID, int32* _changeCounter,
        partition_id childID, int32* _childChangeCounter, const char* _type)
{
        // copy parameters in
        UserStringParameter<false> type;
        int32 changeCounter;
        int32 childChangeCounter;

        status_t error = type.Init(_type, B_DISK_DEVICE_TYPE_LENGTH);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error == B_OK)
                error = copy_from_user_value(childChangeCounter, _childChangeCounter);
        if (error != B_OK)
                return error;


        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register child
        KPartition* child = manager->RegisterPartition(childID);
        if (child == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar3(child, true);

        // check change counters
        if (changeCounter != partition->ChangeCounter()
                || childChangeCounter != child->ChangeCounter()) {
                return B_BAD_VALUE;
        }

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // child must indeed be a child of partition
        if (child->Parent() != partition)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (partition->IsBusy() || child->IsBusy())
                return B_BUSY;
        partition->SetBusy(true);
        child->SetBusy(true);
        locker.Unlock();

        // set the child type
        error = diskSystem->SetType(child, type.value, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->SetBusy(false);
        child->SetBusy(false);

        if (error != B_OK)
                return error;

        // return change counters
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (error == B_OK)
                error = copy_to_user_value(_childChangeCounter, child->ChangeCounter());
        return error;
}


status_t
_user_set_partition_parameters(partition_id partitionID, int32* _changeCounter,
        partition_id childID, int32* _childChangeCounter, const char* _parameters)
{
        // copy parameters in
        UserStringParameter<true> parameters;
        int32 changeCounter;
        int32 childChangeCounter;

        status_t error
                = parameters.Init(_parameters, B_DISK_DEVICE_MAX_PARAMETER_SIZE);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error == B_OK)
                error = copy_from_user_value(childChangeCounter, _childChangeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register child
        KPartition* child = manager->RegisterPartition(childID);
        if (child == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar3(child, true);

        // check change counters
        if (changeCounter != partition->ChangeCounter()
                || childChangeCounter != child->ChangeCounter()) {
                return B_BAD_VALUE;
        }

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // child must indeed be a child of partition
        if (child->Parent() != partition)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (partition->IsBusy() || child->IsBusy())
                return B_BUSY;
        partition->SetBusy(true);
        child->SetBusy(true);
        locker.Unlock();

        // set the child parameters
        error = diskSystem->SetParameters(child, parameters.value, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->SetBusy(false);
        child->SetBusy(false);

        if (error != B_OK)
                return error;

        // return change counters
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (error == B_OK)
                error = copy_to_user_value(_childChangeCounter, child->ChangeCounter());
        return error;
}


status_t
_user_set_partition_content_parameters(partition_id partitionID,
        int32* _changeCounter, const char* _parameters)
{
        // copy parameters in
        UserStringParameter<true> parameters;
        int32 changeCounter;

        status_t error
                = parameters.Init(_parameters, B_DISK_DEVICE_MAX_PARAMETER_SIZE);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(true))
                return B_BUSY;
        locker.Unlock();

        // set content parameters
        error = diskSystem->SetContentParameters(partition, parameters.value,
                DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(true);

        if (error != B_OK)
                return error;

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_initialize_partition(partition_id partitionID, int32* _changeCounter,
        const char* _diskSystemName, const char* _name, const char* _parameters)
{
        // copy parameters in
        UserStringParameter<false> diskSystemName;
        UserStringParameter<true> name;
        UserStringParameter<true> parameters;
        int32 changeCounter;

        status_t error
                = diskSystemName.Init(_diskSystemName, B_DISK_SYSTEM_NAME_LENGTH);
        if (error == B_OK)
                error = name.Init(_name, B_DISK_DEVICE_NAME_LENGTH);
        if (error == B_OK)
                error = parameters.Init(_parameters, B_DISK_DEVICE_MAX_PARAMETER_SIZE);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be uninitialized
        if (partition->DiskSystem() != NULL)
                return B_BAD_VALUE;

        // load the new disk system
        KDiskSystem *diskSystem = manager->LoadDiskSystem(diskSystemName.value,
                true);
        if (diskSystem == NULL)
                return B_ENTRY_NOT_FOUND;
        DiskSystemLoader loader(diskSystem, true);

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(true))
                return B_BUSY;
        locker.Unlock();

        // let the disk system initialize the partition
        error = diskSystem->Initialize(partition, name.value, parameters.value,
                DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(true);

        if (error != B_OK)
                return error;

        // Set the disk system. Re-check whether a disk system is already set on the
        // partition. Some disk systems just write the on-disk structures and let
        // the DDM rescan the partition, in which case the disk system will already
        // be set. In very unfortunate cases the on-disk structure of the previous
        // disk system has not been destroyed and the previous disk system has a
        // higher priority than the new one. The old disk system will thus prevail.
        // Not setting the new disk system will at least prevent that the partition
        // object gets into an inconsistent state.
        if (partition->DiskSystem() == NULL)
                partition->SetDiskSystem(diskSystem);

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_uninitialize_partition(partition_id partitionID, int32* _changeCounter,
        partition_id parentID, int32* _parentChangeCounter)
{
        // copy parameters in
        int32 changeCounter;
        int32 parentChangeCounter;
        bool haveParent = parentID >= 0;

        status_t error = copy_from_user_value(changeCounter, _changeCounter);
        if (haveParent && error == B_OK)
                error = copy_from_user_value(parentChangeCounter, _parentChangeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register parent
        KPartition* parent = NULL;
        if (haveParent)
                parent = manager->RegisterPartition(parentID);

        PartitionRegistrar registrar3(parent, true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;
        if (haveParent && parentChangeCounter != parent->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        if (partition->DiskSystem() == NULL)
                return B_BAD_VALUE;

        // check busy
        if (!partition->CheckAndMarkBusy(true))
                return B_BUSY;

        if (partition->IsMounted() || partition->IsChildMounted())
                return B_BAD_VALUE;

        KDiskSystem* diskSystem = partition->DiskSystem();

        locker.Unlock();

        // Let the disk system uninitialize the partition. This operation is not
        // mandatory. If implemented, it will destroy the on-disk structures, so
        // that the disk system cannot accidentally identify the partition later on.
        if (diskSystem != NULL)
                diskSystem->Uninitialize(partition, DUMMY_JOB_ID);

        // re-lock and uninitialize the partition object
        locker.Lock();
        error = partition->UninitializeContents(true);

        partition->UnmarkBusy(true);

        if (error != B_OK)
                return error;

        // return change counter
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (haveParent && error == B_OK)
                error = copy_to_user_value(_parentChangeCounter, parent->ChangeCounter());
        return error;
}


status_t
_user_create_child_partition(partition_id partitionID, int32* _changeCounter,
        off_t offset, off_t size, const char* _type, const char* _name,
        const char* _parameters, partition_id* childID, int32* childChangeCounter)
{
        // copy parameters in
        UserStringParameter<false> type;
        UserStringParameter<true> name;
        UserStringParameter<true> parameters;
        int32 changeCounter;

        status_t error = type.Init(_type, B_DISK_DEVICE_TYPE_LENGTH);
        if (error == B_OK)
                error = name.Init(_name, B_DISK_DEVICE_NAME_LENGTH);
        if (error == B_OK)
                error = parameters.Init(_parameters, B_DISK_DEVICE_MAX_PARAMETER_SIZE);
        if (error == B_OK)
                error = copy_from_user_value(changeCounter, _changeCounter);
        if (error != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // check change counter
        if (changeCounter != partition->ChangeCounter())
                return B_BAD_VALUE;

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // mark the partition busy and unlock
        if (!partition->CheckAndMarkBusy(false))
                return B_BUSY;
        locker.Unlock();

        // create the child
        KPartition *child = NULL;
        error = diskSystem->CreateChild(partition, offset, size, type.value,
                name.value, parameters.value, DUMMY_JOB_ID, &child, -1);

        // re-lock and unmark busy
        locker.Lock();
        partition->UnmarkBusy(false);

        if (error != B_OK)
                return error;

        if (child == NULL)
                return B_ERROR;

        child->UnmarkBusy(true);

        // return change counter and child ID
        error = copy_to_user_value(_changeCounter, partition->ChangeCounter());
        if (error == B_OK)
                error = copy_to_user_value(childID, child->ID());
        return error;
}


status_t
_user_delete_child_partition(partition_id partitionID, int32* _changeCounter,
        partition_id childID, int32 childChangeCounter)
{
        // copy parameters in
        int32 changeCounter;

        status_t error;
        if ((error = copy_from_user_value(changeCounter, _changeCounter)) != B_OK)
                return error;

        // get the partition
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        KPartition* partition = manager->WriteLockPartition(partitionID);
        if (partition == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar1(partition, true);
        PartitionRegistrar registrar2(partition->Device(), true);
        DeviceWriteLocker locker(partition->Device(), true);

        // register child
        KPartition* child = manager->RegisterPartition(childID);
        if (child == NULL)
                return B_ENTRY_NOT_FOUND;

        PartitionRegistrar registrar3(child, true);

        // check change counters
        if (changeCounter != partition->ChangeCounter()
                || childChangeCounter != child->ChangeCounter()) {
                return B_BAD_VALUE;
        }

        // the partition must be initialized
        KDiskSystem* diskSystem = partition->DiskSystem();
        if (diskSystem == NULL)
                return B_BAD_VALUE;

        // child must indeed be a child of partition
        if (child->Parent() != partition)
                return B_BAD_VALUE;

        // mark the partition and child busy and unlock
        if (partition->IsBusy() || !child->CheckAndMarkBusy(true))
                return B_BUSY;
        partition->SetBusy(true);
        locker.Unlock();

        // delete the child
        error = diskSystem->DeleteChild(child, DUMMY_JOB_ID);

        // re-lock and unmark busy
        locker.Lock();
        partition->SetBusy(false);
        child->UnmarkBusy(true);

        if (error != B_OK)
                return error;

        // return change counter
        return copy_to_user_value(_changeCounter, partition->ChangeCounter());
}


status_t
_user_start_watching_disks(uint32 eventMask, port_id port, int32 token)
{
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        return manager->Notifications().UpdateUserListener(eventMask, port, token);
}


status_t
_user_stop_watching_disks(port_id port, int32 token)
{
        KDiskDeviceManager* manager = KDiskDeviceManager::Default();
        return manager->Notifications().RemoveUserListeners(port, token);
}