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/*
* YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
*
* Copyright (C) 2002-2011 Aleph One Ltd.
* for Toby Churchill Ltd and Brightstar Engineering
*
* 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(int) bytes record size.
* yaffs_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 "yportenv.h"
static int nval_find(const char *xb, int xb_size, const YCHAR *name,
int *exist_size)
{
int pos = 0;
int size;
memcpy(&size, xb, sizeof(int));
while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
if (!yaffs_strncmp((YCHAR *) (xb + pos + sizeof(int)),
name, size)) {
if (exist_size)
*exist_size = size;
return pos;
}
pos += size;
if (pos < xb_size - sizeof(int))
memcpy(&size, xb + pos, sizeof(int));
else
size = 0;
}
if (exist_size)
*exist_size = 0;
return -ENODATA;
}
static int nval_used(const char *xb, int xb_size)
{
int pos = 0;
int size;
memcpy(&size, xb + pos, sizeof(int));
while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
pos += size;
if (pos < xb_size - sizeof(int))
memcpy(&size, xb + pos, sizeof(int));
else
size = 0;
}
return pos;
}
int nval_del(char *xb, int xb_size, const YCHAR *name)
{
int pos = nval_find(xb, xb_size, name, NULL);
int 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(int));
memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
memset(xb + (xb_size - size), 0, size);
return 0;
}
int nval_set(char *xb, int xb_size, const YCHAR *name, const char *buf,
int bsize, int flags)
{
int pos;
int namelen = yaffs_strnlen(name, xb_size);
int reclen;
int size_exist = 0;
int space;
int start;
pos = nval_find(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(xb, xb_size);
space = xb_size - start + size_exist;
reclen = (sizeof(int) + namelen + 1 + bsize);
if (reclen > space)
return -ENOSPC;
if (pos >= 0) {
nval_del(xb, xb_size, name);
start = nval_used(xb, xb_size);
}
pos = start;
memcpy(xb + pos, &reclen, sizeof(int));
pos += sizeof(int);
yaffs_strncpy((YCHAR *) (xb + pos), name, reclen);
pos += (namelen + 1);
memcpy(xb + pos, buf, bsize);
return 0;
}
int nval_get(const char *xb, int xb_size, const YCHAR * name, char *buf,
int bsize)
{
int pos = nval_find(xb, xb_size, name, NULL);
int size;
if (pos >= 0 && pos < xb_size) {
memcpy(&size, xb + pos, sizeof(int));
pos += sizeof(int); /* advance past record length */
size -= sizeof(int);
/* 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(const char *xb, int xb_size, char *buf, int bsize)
{
int pos = 0;
int size;
int name_len;
int ncopied = 0;
int filled = 0;
memcpy(&size, xb + pos, sizeof(int));
while (size > sizeof(int) &&
size <= xb_size &&
(pos + size) < xb_size &&
!filled) {
pos += sizeof(int);
size -= sizeof(int);
name_len = yaffs_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 < xb_size - sizeof(int))
memcpy(&size, xb + pos, sizeof(int));
else
size = 0;
}
return ncopied;
}
int nval_hasvalues(const char *xb, int xb_size)
{
return nval_used(xb, xb_size) > 0;
}
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