mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
df561f6688
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
325 lines
7.2 KiB
C
325 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* linux/fs/adfs/dir_f.c
|
|
*
|
|
* Copyright (C) 1997-1999 Russell King
|
|
*
|
|
* E and F format directory handling
|
|
*/
|
|
#include "adfs.h"
|
|
#include "dir_f.h"
|
|
|
|
/*
|
|
* 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;
|
|
fallthrough;
|
|
case 3: val |= p[2] << 16;
|
|
fallthrough;
|
|
case 2: val |= p[1] << 8;
|
|
fallthrough;
|
|
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;
|
|
fallthrough;
|
|
case 3: p[2] = val >> 16;
|
|
fallthrough;
|
|
case 2: p[1] = val >> 8;
|
|
fallthrough;
|
|
default: p[0] = val;
|
|
}
|
|
}
|
|
|
|
#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);\
|
|
(void *)(_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;
|
|
}
|
|
|
|
static int adfs_f_validate(struct adfs_dir *dir)
|
|
{
|
|
struct adfs_dirheader *head = dir->dirhead;
|
|
struct adfs_newdirtail *tail = dir->newtail;
|
|
|
|
if (head->startmasseq != tail->endmasseq ||
|
|
tail->dirlastmask || tail->reserved[0] || tail->reserved[1] ||
|
|
(memcmp(&head->startname, "Nick", 4) &&
|
|
memcmp(&head->startname, "Hugo", 4)) ||
|
|
memcmp(&head->startname, &tail->endname, 4) ||
|
|
adfs_dir_checkbyte(dir) != tail->dircheckbyte)
|
|
return -EIO;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Read and check that a directory is valid */
|
|
static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
|
|
struct adfs_dir *dir)
|
|
{
|
|
const unsigned int blocksize_bits = sb->s_blocksize_bits;
|
|
int ret;
|
|
|
|
if (size && size != ADFS_NEWDIR_SIZE)
|
|
return -EIO;
|
|
|
|
ret = adfs_dir_read_buffers(sb, indaddr, ADFS_NEWDIR_SIZE, dir);
|
|
if (ret)
|
|
return ret;
|
|
|
|
dir->dirhead = bufoff(dir->bh, 0);
|
|
dir->newtail = bufoff(dir->bh, 2007);
|
|
|
|
if (adfs_f_validate(dir))
|
|
goto bad_dir;
|
|
|
|
dir->parent_id = adfs_readval(dir->newtail->dirparent, 3);
|
|
|
|
return 0;
|
|
|
|
bad_dir:
|
|
adfs_error(sb, "dir %06x is corrupted", indaddr);
|
|
adfs_dir_relse(dir);
|
|
|
|
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)
|
|
{
|
|
unsigned int name_len;
|
|
|
|
for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) {
|
|
if (de->dirobname[name_len] < ' ')
|
|
break;
|
|
|
|
obj->name[name_len] = de->dirobname[name_len];
|
|
}
|
|
|
|
obj->name_len = name_len;
|
|
obj->indaddr = 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;
|
|
|
|
adfs_object_fixup(dir, obj);
|
|
}
|
|
|
|
/*
|
|
* 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->indaddr);
|
|
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 adfs_direntry de;
|
|
int ret;
|
|
|
|
ret = adfs_dir_copyfrom(&de, dir, pos, 26);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (!de.dirobname[0])
|
|
return -ENOENT;
|
|
|
|
adfs_dir2obj(dir, obj, &de);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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_iterate(struct adfs_dir *dir, struct dir_context *ctx)
|
|
{
|
|
struct object_info obj;
|
|
int pos = 5 + (ctx->pos - 2) * 26;
|
|
|
|
while (ctx->pos < 2 + ADFS_NUM_DIR_ENTRIES) {
|
|
if (__adfs_dir_get(dir, pos, &obj))
|
|
break;
|
|
if (!dir_emit(ctx, obj.name, obj.name_len,
|
|
obj.indaddr, DT_UNKNOWN))
|
|
break;
|
|
pos += 26;
|
|
ctx->pos++;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
|
|
{
|
|
struct adfs_direntry de;
|
|
int offset, ret;
|
|
|
|
offset = 5 - (int)sizeof(de);
|
|
|
|
do {
|
|
offset += sizeof(de);
|
|
ret = adfs_dir_copyfrom(&de, dir, offset, sizeof(de));
|
|
if (ret) {
|
|
adfs_error(dir->sb, "error reading directory entry");
|
|
return -ENOENT;
|
|
}
|
|
if (!de.dirobname[0]) {
|
|
adfs_error(dir->sb, "unable to locate entry to update");
|
|
return -ENOENT;
|
|
}
|
|
} while (adfs_readval(de.dirinddiscadd, 3) != obj->indaddr);
|
|
|
|
/* Update the directory entry with the new object state */
|
|
adfs_obj2dir(&de, obj);
|
|
|
|
/* Write the directory entry back to the directory */
|
|
return adfs_dir_copyto(dir, offset, &de, 26);
|
|
}
|
|
|
|
static int adfs_f_commit(struct adfs_dir *dir)
|
|
{
|
|
int ret;
|
|
|
|
/* Increment directory sequence number */
|
|
dir->dirhead->startmasseq += 1;
|
|
dir->newtail->endmasseq += 1;
|
|
|
|
/* Update directory check byte */
|
|
dir->newtail->dircheckbyte = adfs_dir_checkbyte(dir);
|
|
|
|
/* Make sure the directory still validates correctly */
|
|
ret = adfs_f_validate(dir);
|
|
if (ret)
|
|
adfs_msg(dir->sb, KERN_ERR, "error: update broke directory");
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct adfs_dir_ops adfs_f_dir_ops = {
|
|
.read = adfs_f_read,
|
|
.iterate = adfs_f_iterate,
|
|
.setpos = adfs_f_setpos,
|
|
.getnext = adfs_f_getnext,
|
|
.update = adfs_f_update,
|
|
.commit = adfs_f_commit,
|
|
};
|