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linux-next/fs/adfs/dir_f.c
Stuart Swales da23ef0549 adfs: add hexadecimal filetype suffix option
ADFS (FileCore) storage complies with the RISC OS filetype specification
(12 bits of file type information is stored in the file load address,
rather than using a file extension).  The existing driver largely ignores
this information and does not present it to the end user.

It is desirable that stored filetypes be made visible to the end user to
facilitate a precise copy of data and metadata from a hard disc (or image
thereof) into a RISC OS emulator (such as RPCEmu) or to a network share
which can be accessed by real Acorn systems.

This patch implements a per-mount filetype suffix option (use -o
ftsuffix=1) to present any filetype as a ,xyz hexadecimal suffix on each
file.  This type suffix is compatible with that used by RISC OS systems
that access network servers using NFS client software and by RPCemu's host
filing system.

Signed-off-by: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:17 -07:00

487 lines
10 KiB
C

/*
* 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/buffer_head.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 ((unsigned char)*ptr >= ' ' && maxlen--) {
if (*ptr == '/')
*buf++ = '.';
else
*buf++ = *ptr;
ptr++;
}
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 adfs_dir *dir, 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;
obj->filetype = -1;
/*
* object is a file and is filetyped and timestamped?
* RISC OS 12-bit filetype is stored in load_address[19:8]
*/
if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
(0xfff00000 == (0xfff00000 & obj->loadaddr))) {
obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);
/* optionally append the ,xyz hex filetype suffix */
if (ADFS_SB(dir->sb)->s_ftsuffix)
obj->name_len +=
append_filetype_suffix(
&obj->name[obj->name_len],
obj->filetype);
}
}
/*
* 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 *sb = dir->sb;
struct adfs_direntry de;
int thissize, buffer, offset;
buffer = pos >> sb->s_blocksize_bits;
if (buffer > dir->nr_buffers)
return -EINVAL;
offset = pos & (sb->s_blocksize - 1);
thissize = sb->s_blocksize - offset;
if (thissize > 26)
thissize = 26;
memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
if (thissize != 26)
memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
26 - thissize);
if (!de.dirobname[0])
return -ENOENT;
adfs_dir2obj(dir, obj, &de);
return 0;
}
static int
__adfs_dir_put(struct adfs_dir *dir, int pos, struct object_info *obj)
{
struct super_block *sb = dir->sb;
struct adfs_direntry de;
int thissize, buffer, offset;
buffer = pos >> sb->s_blocksize_bits;
if (buffer > dir->nr_buffers)
return -EINVAL;
offset = pos & (sb->s_blocksize - 1);
thissize = sb->s_blocksize - offset;
if (thissize > 26)
thissize = 26;
/*
* Get the entry in total
*/
memcpy(&de, dir->bh[buffer]->b_data + offset, thissize);
if (thissize != 26)
memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data,
26 - thissize);
/*
* update it
*/
adfs_obj2dir(&de, obj);
/*
* Put the new entry back
*/
memcpy(dir->bh[buffer]->b_data + offset, &de, thissize);
if (thissize != 26)
memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize,
26 - thissize);
return 0;
}
/*
* the caller is responsible for holding the necessary
* locks.
*/
static int
adfs_dir_find_entry(struct adfs_dir *dir, unsigned long object_id)
{
int pos, ret;
ret = -ENOENT;
for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) {
struct object_info obj;
if (!__adfs_dir_get(dir, pos, &obj))
break;
if (obj.file_id == object_id) {
ret = pos;
break;
}
}
return ret;
}
static int
adfs_f_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
{
int ret;
if (sz != ADFS_NEWDIR_SIZE)
return -EIO;
ret = adfs_dir_read(sb, id, sz, dir);
if (ret)
adfs_error(sb, "unable to read directory");
else
dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);
return ret;
}
static int
adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
{
if (fpos >= ADFS_NUM_DIR_ENTRIES)
return -ENOENT;
dir->pos = 5 + fpos * 26;
return 0;
}
static int
adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj)
{
unsigned int ret;
ret = __adfs_dir_get(dir, dir->pos, obj);
if (ret == 0)
dir->pos += 26;
return ret;
}
static int
adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
{
struct super_block *sb = dir->sb;
int ret, i;
ret = adfs_dir_find_entry(dir, obj->file_id);
if (ret < 0) {
adfs_error(dir->sb, "unable to locate entry to update");
goto out;
}
__adfs_dir_put(dir, ret, obj);
/*
* Increment directory sequence number
*/
dir->bh[0]->b_data[0] += 1;
dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;
ret = adfs_dir_checkbyte(dir);
/*
* Update directory check byte
*/
dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;
#if 1
{
const unsigned int blocksize_bits = sb->s_blocksize_bits;
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;
}
#endif
for (i = dir->nr_buffers - 1; i >= 0; i--)
mark_buffer_dirty(dir->bh[i]);
ret = 0;
out:
return ret;
#if 1
bad_dir:
adfs_error(dir->sb, "whoops! I broke a directory!");
return -EIO;
#endif
}
static int
adfs_f_sync(struct adfs_dir *dir)
{
int err = 0;
int i;
for (i = dir->nr_buffers - 1; i >= 0; i--) {
struct buffer_head *bh = dir->bh[i];
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh))
err = -EIO;
}
return err;
}
static void
adfs_f_free(struct adfs_dir *dir)
{
int i;
for (i = dir->nr_buffers - 1; i >= 0; i--) {
brelse(dir->bh[i]);
dir->bh[i] = NULL;
}
dir->nr_buffers = 0;
dir->sb = NULL;
}
struct adfs_dir_ops adfs_f_dir_ops = {
.read = adfs_f_read,
.setpos = adfs_f_setpos,
.getnext = adfs_f_getnext,
.update = adfs_f_update,
.sync = adfs_f_sync,
.free = adfs_f_free
};