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/*
* YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
*
* Copyright (C) 2002-2018 Aleph One Ltd.
*
* Created by Charles Manning <charles@aleph1.co.uk>
*
* 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.
*/
/*
* This simple implementation of a name-value store assumes a small number of
* values and fits into a small finite buffer.
*
* Each attribute is stored as a record:
* sizeof(size) bytes record size.
* strnlen+1 bytes name null terminated.
* nbytes value.
* ----------
* total size stored in record size
*
* This code has not been tested with unicode yet.
*/
#include "yaffs_nameval.h"
#include "yaffs_guts.h"
#include "yportenv.h"
#include "yaffs_endian.h"
static int nval_find(struct yaffs_dev *dev,
const char *xb, int xb_size, const YCHAR *name,
int *exist_size)
{
int pos = 0;
s32 size;
memcpy(&size, xb, sizeof(size));
yaffs_do_endian_s32(dev, &size);
while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
if (!strncmp((YCHAR *) (xb + pos + sizeof(size)),
name, size)) {
if (exist_size)
*exist_size = size;
return pos;
}
pos += size;
if (pos < (int)(xb_size - sizeof(size))) {
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
} else
size = 0;
}
if (exist_size)
*exist_size = 0;
return -ENODATA;
}
static int nval_used(struct yaffs_dev *dev, const char *xb, int xb_size)
{
int pos = 0;
s32 size;
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
pos += size;
if (pos < (int)(xb_size - sizeof(size))) {
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
} else
size = 0;
}
return pos;
}
int nval_del(struct yaffs_dev *dev, char *xb, int xb_size, const YCHAR *name)
{
int pos = nval_find(dev, xb, xb_size, name, NULL);
s32 size;
if (pos < 0 || pos >= xb_size)
return -ENODATA;
/* Find size, shift rest over this record,
* then zero out the rest of buffer */
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
memset(xb + (xb_size - size), 0, size);
return 0;
}
int nval_set(struct yaffs_dev *dev,
char *xb, int xb_size, const YCHAR *name, const char *buf,
int bsize, int flags)
{
int pos;
int namelen = strnlen(name, xb_size);
int size_exist = 0;
int space;
int start;
s32 reclen;
s32 reclen_endianised;
pos = nval_find(dev, xb, xb_size, name, &size_exist);
if (flags & XATTR_CREATE && pos >= 0)
return -EEXIST;
if (flags & XATTR_REPLACE && pos < 0)
return -ENODATA;
start = nval_used(dev, xb, xb_size);
space = xb_size - start + size_exist;
reclen = (sizeof(reclen) + namelen + 1 + bsize);
if (reclen > space)
return -ENOSPC;
if (pos >= 0) {
/* Exists, so delete it. */
nval_del(dev, xb, xb_size, name);
start = nval_used(dev, xb, xb_size);
}
pos = start;
reclen_endianised = reclen;
yaffs_do_endian_s32(dev, &reclen_endianised);
memcpy(xb + pos, &reclen_endianised, sizeof(reclen_endianised));
pos += sizeof(reclen_endianised);
strncpy((YCHAR *) (xb + pos), name, reclen);
pos += (namelen + 1);
memcpy(xb + pos, buf, bsize);
return 0;
}
int nval_get(struct yaffs_dev *dev,
const char *xb, int xb_size, const YCHAR * name, char *buf,
int bsize)
{
int pos = nval_find(dev, xb, xb_size, name, NULL);
s32 size;
if (pos >= 0 && pos < xb_size) {
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
pos += sizeof(size); /* advance past record length */
size -= sizeof(size);
/* Advance over name string */
while (xb[pos] && size > 0 && pos < xb_size) {
pos++;
size--;
}
/*Advance over NUL */
pos++;
size--;
/* If bsize is zero then this is a size query.
* Return the size, but don't copy.
*/
if (!bsize)
return size;
if (size <= bsize) {
memcpy(buf, xb + pos, size);
return size;
}
}
if (pos >= 0)
return -ERANGE;
return -ENODATA;
}
int nval_list(struct yaffs_dev *dev, const char *xb, int xb_size, char *buf, int bsize)
{
int pos = 0;
s32 size;
int name_len;
int ncopied = 0;
int filled = 0;
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
while (size > (int)(sizeof(size)) &&
size <= xb_size &&
(pos + size) < xb_size &&
!filled) {
pos += sizeof(size);
size -= sizeof(size);
name_len = strnlen((YCHAR *) (xb + pos), size);
if (ncopied + name_len + 1 < bsize) {
memcpy(buf, xb + pos, name_len * sizeof(YCHAR));
buf += name_len;
*buf = '\0';
buf++;
if (sizeof(YCHAR) > 1) {
*buf = '\0';
buf++;
}
ncopied += (name_len + 1);
} else {
filled = 1;
}
pos += size;
if (pos < (int)(xb_size - sizeof(size))) {
memcpy(&size, xb + pos, sizeof(size));
yaffs_do_endian_s32(dev, &size);
}
else
size = 0;
}
return ncopied;
}
int nval_hasvalues(struct yaffs_dev *dev, const char *xb, int xb_size)
{
return nval_used(dev, xb, xb_size) > 0;
}
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