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sortix--sortix/kernel/partition.cpp
2014-03-01 14:37:39 +01:00

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2.6 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
This file is part of Sortix.
Sortix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
Sortix. If not, see <http://www.gnu.org/licenses/>.
partition.cpp
Block device representing a partition of another block device.
*******************************************************************************/
#include <sys/types.h>
#include <errno.h>
#include <sortix/seek.h>
#include <sortix/kernel/inode.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/refcount.h>
#include "partition.h"
namespace Sortix {
Partition::Partition(Ref<Inode> inner_inode, off_t start, off_t length)
{
this->dev = (dev_t) this;
this->ino = (ino_t) this;
this->inode_type = INODE_TYPE_FILE;
this->inner_inode = inner_inode;
this->start = start;
this->length = length;
this->stat_size = length;
}
Partition::~Partition()
{
}
int Partition::sync(ioctx_t* ctx)
{
return inner_inode->sync(ctx);
}
int Partition::truncate(ioctx_t* /*ctx*/, off_t new_length)
{
if ( new_length != length )
return errno = EPERM, -1;
return 0;
}
off_t Partition::lseek(ioctx_t* /*ctx*/, off_t offset, int whence)
{
if ( whence == SEEK_SET )
return offset;
if ( whence == SEEK_END )
// TODO: Avoid underflow and overflow!
return length + offset;
return errno = EINVAL, -1;
}
ssize_t Partition::pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off)
{
// TODO: Avoid underflow and overflow!
off_t end_at = off + count;
if ( length <= end_at )
return 0;
off_t available = length - off;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
return inner_inode->pread(ctx, buf, count, start + off);
}
ssize_t Partition::pwrite(ioctx_t* ctx, const uint8_t* buf, size_t count,
off_t off)
{
// TODO: Avoid underflow and overflow!
off_t end_at = off + count;
if ( length <= end_at )
return 0;
off_t available = length - off;
if ( (uintmax_t) available < (uintmax_t) count )
count = available;
return inner_inode->pwrite(ctx, buf, count, start + off);
}
}