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/*
* linux/fs/adfs/dir_f.c
*
* Copyright (C) 1997-1999 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* E and F format directory handling
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/adfs_fs.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/spinlock.h>
#include <linux/buffer_head.h>
#include <linux/string.h>
#include "adfs.h"
#include "dir_f.h"
static void adfs_f_free(struct adfs_dir *dir);
/*
* Read an (unaligned) value of length 1..4 bytes
*/
static inline unsigned int adfs_readval(unsigned char *p, int len)
{
unsigned int val = 0;
switch (len) {
case 4: val |= p[3] << 24;
case 3: val |= p[2] << 16;
case 2: val |= p[1] << 8;
default: val |= p[0];
}
return val;
}
static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
{
switch (len) {
case 4: p[3] = val >> 24;
case 3: p[2] = val >> 16;
case 2: p[1] = val >> 8;
default: p[0] = val;
}
}
static inline int adfs_readname(char *buf, char *ptr, int maxlen)
{
char *old_buf = buf;
while (*ptr >= ' ' && maxlen--) {
if (*ptr == '/')
*buf++ = '.';
else
*buf++ = *ptr;
ptr++;
}
*buf = '\0';
return buf - old_buf;
}
#define ror13(v) ((v >> 13) | (v << 19))
#define dir_u8(idx) \
({ int _buf = idx >> blocksize_bits; \
int _off = idx - (_buf << blocksize_bits);\
*(u8 *)(bh[_buf]->b_data + _off); \
})
#define dir_u32(idx) \
({ int _buf = idx >> blocksize_bits; \
int _off = idx - (_buf << blocksize_bits);\
*(__le32 *)(bh[_buf]->b_data + _off); \
})
#define bufoff(_bh,_idx) \
({ int _buf = _idx >> blocksize_bits; \
int _off = _idx - (_buf << blocksize_bits);\
(u8 *)(_bh[_buf]->b_data + _off); \
})
/*
* There are some algorithms that are nice in
* assembler, but a bitch in C... This is one
* of them.
*/
static u8
adfs_dir_checkbyte(const struct adfs_dir *dir)
{
struct buffer_head * const *bh = dir->bh;
const int blocksize_bits = dir->sb->s_blocksize_bits;
union { __le32 *ptr32; u8 *ptr8; } ptr, end;
u32 dircheck = 0;
int last = 5 - 26;
int i = 0;
/*
* Accumulate each word up to the last whole
* word of the last directory entry. This
* can spread across several buffer heads.
*/
do {
last += 26;
do {
dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);
i += sizeof(u32);
} while (i < (last & ~3));
} while (dir_u8(last) != 0);
/*
* Accumulate the last few bytes. These
* bytes will be within the same bh.
*/
if (i != last) {
ptr.ptr8 = bufoff(bh, i);
end.ptr8 = ptr.ptr8 + last - i;
do
dircheck = *ptr.ptr8++ ^ ror13(dircheck);
while (ptr.ptr8 < end.ptr8);
}
/*
* The directory tail is in the final bh
* Note that contary to the RISC OS PRMs,
* the first few bytes are NOT included
* in the check. All bytes are in the
* same bh.
*/
ptr.ptr8 = bufoff(bh, 2008);
end.ptr8 = ptr.ptr8 + 36;
do {
__le32 v = *ptr.ptr32++;
dircheck = le32_to_cpu(v) ^ ror13(dircheck);
} while (ptr.ptr32 < end.ptr32);
return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
}
/*
* Read and check that a directory is valid
*/
static int
adfs_dir_read(struct super_block *sb, unsigned long object_id,
unsigned int size, struct adfs_dir *dir)
{
const unsigned int blocksize_bits = sb->s_blocksize_bits;
int blk = 0;
/*
* Directories which are not a multiple of 2048 bytes
* are considered bad v2 [3.6]
*/
if (size & 2047)
goto bad_dir;
size >>= blocksize_bits;
dir->nr_buffers = 0;
dir->sb = sb;
for (blk = 0; blk < size; blk++) {
int phys;
phys = __adfs_block_map(sb, object_id, blk);
if (!phys) {
adfs_error(sb, "dir object %lX has a hole at offset %d",
object_id, blk);
goto release_buffers;
}
dir->bh[blk] = sb_bread(sb, phys);
if (!dir->bh[blk])
goto release_buffers;
}
memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
goto bad_dir;
if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
memcmp(&dir->dirhead.startname, "Hugo", 4))
goto bad_dir;
if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
goto bad_dir;
dir->nr_buffers = blk;
return 0;
bad_dir:
adfs_error(sb, "corrupted directory fragment %lX",
object_id);
release_buffers:
for (blk -= 1; blk >= 0; blk -= 1)
brelse(dir->bh[blk]);
dir->sb = NULL;
return -EIO;
}
/*
* convert a disk-based directory entry to a Linux ADFS directory entry
*/
static inline void
adfs_dir2obj(struct object_info *obj, struct adfs_direntry *de)
{
obj->name_len = adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN);
obj->file_id = adfs_readval(de->dirinddiscadd, 3);
obj->loadaddr = adfs_readval(de->dirload, 4);
obj->execaddr = adfs_readval(de->direxec, 4);
obj->size = adfs_readval(de->dirlen, 4);
obj->attr = de->newdiratts;
}
/*
* convert a Linux ADFS directory entry to a disk-based directory entry
*/
static inline void
adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj)
{
adfs_writeval(de->dirinddiscadd, 3, obj->file_id);
adfs_writeval(de->dirload, 4, obj->loadaddr);
adfs_writeval(de->direxec, 4, obj->execaddr);
adfs_writeval(de->dirlen, 4, obj->size);
de->newdiratts = obj->attr;
}
/*
* get a directory entry. Note that the caller is responsible
* for holding the relevant locks.
*/
static int
__adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj)
{
struct super_block
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