mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
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198 lines
4.2 KiB
C
198 lines
4.2 KiB
C
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/*
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* YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
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*
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* Copyright (C) 2002-2010 Aleph One Ltd.
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* for Toby Churchill Ltd and Brightstar Engineering
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*
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* Created by Charles Manning <charles@aleph1.co.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/*
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* This simple implementation of a name-value store assumes a small number of values and fits
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* into a small finite buffer.
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*
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* Each attribute is stored as a record:
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* sizeof(int) bytes record size.
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* strnlen+1 bytes name null terminated.
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* nbytes value.
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* ----------
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* total size stored in record size
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*
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* This code has not been tested with unicode yet.
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*/
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#include "yaffs_nameval.h"
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#include "yportenv.h"
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static int nval_find(const char *xb, int xb_size, const YCHAR *name,
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int *exist_size)
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{
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int pos=0;
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int size;
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memcpy(&size,xb,sizeof(int));
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while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
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if(yaffs_strncmp((YCHAR *)(xb+pos+sizeof(int)),name,size) == 0){
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if(exist_size)
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*exist_size = size;
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return pos;
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}
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pos += size;
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if(pos < xb_size -sizeof(int))
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memcpy(&size,xb + pos,sizeof(int));
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else
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size = 0;
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}
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if(exist_size)
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*exist_size = 0;
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return -1;
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}
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static int nval_used(const char *xb, int xb_size)
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{
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int pos=0;
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int size;
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memcpy(&size,xb + pos,sizeof(int));
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while(size > 0 && (size < xb_size) && (pos + size < xb_size)){
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pos += size;
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if(pos < xb_size -sizeof(int))
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memcpy(&size,xb + pos,sizeof(int));
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else
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size = 0;
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}
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return pos;
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}
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int nval_del(char *xb, int xb_size, const YCHAR *name)
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{
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int pos = nval_find(xb, xb_size, name, NULL);
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int size;
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if(pos >= 0 && pos < xb_size){
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/* Find size, shift rest over this record, then zero out the rest of buffer */
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memcpy(&size,xb+pos,sizeof(int));
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memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
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memset(xb + (xb_size - size),0,size);
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return 0;
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} else
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return -ENODATA;
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}
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int nval_set(char *xb, int xb_size, const YCHAR *name, const char *buf, int bsize, int flags)
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{
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int pos;
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int namelen = yaffs_strnlen(name,xb_size);
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int reclen;
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int size_exist = 0;
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int space;
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int start;
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pos = nval_find(xb,xb_size,name, &size_exist);
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if(flags & XATTR_CREATE && pos >= 0)
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return -EEXIST;
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if(flags & XATTR_REPLACE && pos < 0)
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return -ENODATA;
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start = nval_used(xb,xb_size);
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space = xb_size - start + size_exist;
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reclen = (sizeof(int) + namelen + 1 + bsize);
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if(reclen > space)
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return -ENOSPC;
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if(pos >= 0){
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nval_del(xb,xb_size,name);
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start = nval_used(xb, xb_size);
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}
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pos = start;
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memcpy(xb + pos,&reclen,sizeof(int));
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pos +=sizeof(int);
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yaffs_strncpy((YCHAR *)(xb + pos), name, reclen);
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pos+= (namelen+1);
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memcpy(xb + pos,buf,bsize);
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return 0;
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}
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int nval_get(const char *xb, int xb_size, const YCHAR *name, char *buf, int bsize)
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{
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int pos = nval_find(xb,xb_size,name,NULL);
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int size;
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if(pos >= 0 && pos< xb_size){
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memcpy(&size,xb +pos,sizeof(int));
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pos+=sizeof(int); /* advance past record length */
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size -= sizeof(int);
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/* Advance over name string */
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while(xb[pos] && size > 0 && pos < xb_size){
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pos++;
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size--;
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}
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/*Advance over NUL */
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pos++;
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size--;
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if(size <= bsize){
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memcpy(buf,xb + pos,size);
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return size;
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}
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}
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if(pos >= 0)
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return -ERANGE;
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else
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return -ENODATA;
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}
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int nval_list(const char *xb, int xb_size, char *buf, int bsize)
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{
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int pos = 0;
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int size;
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int name_len;
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int ncopied = 0;
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int filled = 0;
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memcpy(&size,xb + pos,sizeof(int));
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while(size > sizeof(int) && size <= xb_size && (pos + size) < xb_size && !filled){
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pos+= sizeof(int);
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size-=sizeof(int);
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name_len = yaffs_strnlen((YCHAR *)(xb + pos), size);
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if(ncopied + name_len + 1 < bsize){
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memcpy(buf,xb+pos,name_len * sizeof(YCHAR));
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buf+= name_len;
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*buf = '\0';
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buf++;
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if(sizeof(YCHAR) > 1){
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*buf = '\0';
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buf++;
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}
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ncopied += (name_len+1);
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} else
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filled = 1;
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pos+=size;
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if(pos < xb_size -sizeof(int))
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memcpy(&size,xb + pos,sizeof(int));
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else
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size = 0;
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}
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return ncopied;
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}
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int nval_hasvalues(const char *xb, int xb_size)
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{
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return nval_used(xb, xb_size) > 0;
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}
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