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102 lines
2.4 KiB
C++
102 lines
2.4 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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fs/zero.cpp
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Bit bucket special device.
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*******************************************************************************/
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#include <sys/types.h>
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#include <stdint.h>
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#include <string.h>
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#include <sortix/stat.h>
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#include <sortix/kernel/inode.h>
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#include <sortix/kernel/ioctx.h>
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#include "zero.h"
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namespace Sortix {
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Zero::Zero(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode)
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{
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inode_type = INODE_TYPE_STREAM;
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if ( !dev )
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dev = (dev_t) this;
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if ( !ino )
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ino = (ino_t) this;
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this->type = S_IFCHR;
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this->stat_uid = owner;
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this->stat_gid = group;
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this->stat_mode = (mode & S_SETABLE) | this->type;
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this->stat_size = 0;
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this->stat_blksize = 1;
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this->dev = dev;
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this->ino = ino;
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}
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Zero::~Zero()
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{
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}
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int Zero::truncate(ioctx_t* /*ctx*/, off_t /*length*/)
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{
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return 0;
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}
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off_t Zero::lseek(ioctx_t* /*ctx*/, off_t offset, int /*whence*/)
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{
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return offset;
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}
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ssize_t Zero::read(ioctx_t* ctx, uint8_t* buf, size_t count)
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{
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const size_t ZERO_MEM_SIZE = 128;
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uint8_t zero_mem[ZERO_MEM_SIZE];
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memset(zero_mem, 0, ZERO_MEM_SIZE);
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size_t sofar = 0;
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while ( sofar < count )
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{
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size_t left = count - sofar;
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size_t amount = left < ZERO_MEM_SIZE ? left : ZERO_MEM_SIZE;
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ctx->copy_to_dest(buf + sofar, zero_mem, amount);
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sofar += amount;
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}
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return (ssize_t) sofar;
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}
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ssize_t Zero::pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t /*off*/)
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{
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return read(ctx, buf, count);
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}
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ssize_t Zero::write(ioctx_t* /*ctx*/, const uint8_t* /*buf*/, size_t count)
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{
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return count;
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}
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ssize_t Zero::pwrite(ioctx_t* /*ctx*/, const uint8_t* /*buf*/, size_t count,
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off_t /*off*/)
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{
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return count;
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}
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} // namespace Sortix
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