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/* vi: set sw=4 ts=4: */
/*
* inode_io.c --- This is allows an inode in an ext2 filesystem image
* to be accessed via the I/O manager interface.
*
* Copyright (C) 2002 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <time.h>
#include "ext2_fs.h"
#include "ext2fs.h"
/*
* For checking structure magic numbers...
*/
#define EXT2_CHECK_MAGIC(struct, code) \
if ((struct)->magic != (code)) return (code)
struct inode_private_data {
int magic;
char name[32];
ext2_file_t file;
ext2_filsys fs;
ext2_ino_t ino;
struct ext2_inode inode;
int flags;
struct inode_private_data *next;
};
#define CHANNEL_HAS_INODE 0x8000
static struct inode_private_data *top_intern;
static int ino_unique = 0;
static errcode_t inode_open(const char *name, int flags, io_channel *channel);
static errcode_t inode_close(io_channel channel);
static errcode_t inode_set_blksize(io_channel channel, int blksize);
static errcode_t inode_read_blk(io_channel channel, unsigned long block,
int count, void *data);
static errcode_t inode_write_blk(io_channel channel, unsigned long block,
int count, const void *data);
static errcode_t inode_flush(io_channel channel);
static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
int size, const void *data);
static struct struct_io_manager struct_inode_manager = {
EXT2_ET_MAGIC_IO_MANAGER,
"Inode I/O Manager",
inode_open,
inode_close,
inode_set_blksize,
inode_read_blk,
inode_write_blk,
inode_flush,
inode_write_byte
};
io_manager inode_io_manager = &struct_inode_manager;
errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode,
char **name)
{
struct inode_private_data *data;
errcode_t retval;
if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
&data)))
return retval;
data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
sprintf(data->name, "%u:%d", ino, ino_unique++);
data->file = 0;
data->fs = fs;
data->ino = ino;
data->flags = 0;
if (inode) {
memcpy(&data->inode, inode, sizeof(struct ext2_inode));
data->flags |= CHANNEL_HAS_INODE;
}
data->next = top_intern;
top_intern = data;
*name = data->name;
return 0;
}
errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
char **name)
{
return ext2fs_inode_io_intern2(fs, ino, NULL, name);
}
static errcode_t inode_open(const char *name, int flags, io_channel *channel)
{
io_channel io = NULL;
struct inode_private_data *prev, *data = NULL;
errcode_t retval;
int open_flags;
if (name == 0)
return EXT2_ET_BAD_DEVICE_NAME;
for (data = top_intern, prev = NULL; data;
prev = data, data = data->next)
if (strcmp(name, data->name) == 0)
break;
if (!data)
return ENOENT;
if (prev)
prev->next = data->next;
else
top_intern = data->next;
retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
if (retval)
goto cleanup;
memset(io, 0, sizeof(struct struct_io_channel));
io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
io->manager = inode_io_manager;
retval = ext2fs_get_mem(strlen(name)+1, &io->name);
if (retval)
goto cleanup;
strcpy(io->name, name);
io->private_data = data;
io->block_size = 1024;
io->read_error = 0;
io->write_error = 0;
io->refcount = 1;
open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
retval = ext2fs_file_open2(data->fs, data->ino,
(data->flags & CHANNEL_HAS_INODE) ?
&data->inode : 0, open_flags,
&data->file);
if (retval)
goto cleanup;
*channel = io;
return 0;
cleanup:
if (data) {
ext2fs_free_mem(&data);
}
if (io)
ext2fs_free_mem(&io);
return retval;
}
static errcode_t inode_close(io_channel channel)
{
struct inode_private_data *data;
errcode_t retval = 0;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if (--channel->refcount > 0)
return 0;
retval = ext2fs_file_close(data->file);
ext2fs_free_mem(&channel->private_data);
if (channel->name)
ext2fs_free_mem(&channel->name);
ext2fs_free_mem(&channel);
return retval;
}
static errcode_t inode_set_blksize(io_channel channel, int blksize)
{
struct inode_private_data *data;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
channel->block_size = blksize;
return 0;
}
static errcode_t inode_read_blk(io_channel channel, unsigned long block,
int count, void *buf)
{
struct inode_private_data *data;
errcode_t retval;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if ((retval = ext2fs_file_lseek(data->file,
block * channel->block_size,
EXT2_SEEK_SET, 0)))
return retval;
count = (count < 0) ? -count : (count * channel->block_size);
return ext2fs_file_read(data->file, buf, count, 0);
}
static errcode_t inode_write_blk(io_channel channel, unsigned long block,
int count, const void *buf)
{
struct inode_private_data *data;
errcode_t retval;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if ((retval = ext2fs_file_lseek(data->file,
block * channel->block_size,
EXT2_SEEK_SET, 0)))
return retval;
count = (count < 0) ? -count : (count * channel->block_size);
return ext2fs_file_write(data->file, buf, count, 0);
}
static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
int size, const void *buf)
{
struct inode_private_data *data;
errcode_t retval = 0;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
if ((retval = ext2fs_file_lseek(data->file, offset,
EXT2_SEEK_SET, 0)))
return retval;
return ext2fs_file_write(data->file, buf, size, 0);
}
/*
* Flush data buffers to disk.
*/
static errcode_t inode_flush(io_channel channel)
{
struct inode_private_data *data;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct inode_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
return ext2fs_file_flush(data->file);
}
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