130 lines
3.4 KiB
C++
130 lines
3.4 KiB
C++
/*
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* Copyright (c) 2013, 2015, 2017 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* partition.cpp
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* Block device representing a partition of another block device.
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*/
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <sortix/seek.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 <sortix/kernel/kernel.h>
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#include <sortix/kernel/refcount.h>
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#include "partition.h"
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namespace Sortix {
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Partition::Partition(Ref<Inode> inner_inode, off_t start, off_t length)
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{
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assert(0 <= start);
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assert(0 <= length);
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assert(length <= OFF_MAX - start);
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assert(!(inner_inode->type & S_IFNEVERWRAP));
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assert(S_ISBLK(inner_inode->type) || S_ISREG(inner_inode->type));
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this->dev = (dev_t) this;
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this->ino = (ino_t) this;
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this->type = inner_inode->type;
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this->inode_type = INODE_TYPE_FILE;
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this->inner_inode = inner_inode;
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this->start = start;
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this->length = length;
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}
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Partition::~Partition()
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{
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}
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int Partition::sync(ioctx_t* ctx)
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{
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return inner_inode->sync(ctx);
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}
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int Partition::truncate(ioctx_t* /*ctx*/, off_t new_length)
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{
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if ( new_length != length )
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return errno = EPERM, -1;
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return 0;
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}
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off_t Partition::lseek(ioctx_t* /*ctx*/, off_t offset, int whence)
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{
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if ( whence == SEEK_END && offset == 0 )
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return length;
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return errno = EINVAL, -1;
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}
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ssize_t Partition::pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off)
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{
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if ( off < 0 )
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return errno = EINVAL, -1;
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if ( length <= off )
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return 0;
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off_t available = length - off;
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if ( (uintmax_t) available < (uintmax_t) count )
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count = available;
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if ( count == 0 )
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return 0;
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off_t final_offset;
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if ( __builtin_add_overflow(start, off, &final_offset) )
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return errno = EOVERFLOW, -1;
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assert(start <= final_offset);
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assert(final_offset < start + length);
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return inner_inode->pread(ctx, buf, count, final_offset);
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}
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ssize_t Partition::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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if ( off < 0 )
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return errno = EINVAL, -1;
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if ( length <= off )
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return count ? (errno = EFBIG, -1) : 0;
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off_t available = length - off;
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if ( (uintmax_t) available < (uintmax_t) count )
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count = available;
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if ( count == 0 )
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return 0;
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off_t final_offset;
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if ( __builtin_add_overflow(start, off, &final_offset) )
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return errno = EOVERFLOW, -1;
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assert(start <= final_offset);
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assert(final_offset < start + length);
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return inner_inode->pwrite(ctx, buf, count, final_offset);
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}
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int Partition::stat(ioctx_t* ctx, struct stat* st)
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{
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if ( inner_inode->stat(ctx, st) < 0 )
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return -1;
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struct stat myst;
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if ( !ctx->copy_from_src(&myst, st, sizeof(myst)) )
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return -1;
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myst.st_size = length;
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myst.st_blocks = length / 512;
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if ( !ctx->copy_to_dest(st, &myst, sizeof(myst)) )
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return -1;
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return 0;
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}
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}
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