2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
4 * Copyright (C) 2002-2011 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
7 * Created by Charles Manning <charles@aleph1.co.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 * This simple implementation of a name-value store assumes a small number of
16 * values and fits into a small finite buffer.
18 * Each attribute is stored as a record:
19 * sizeof(size) bytes record size.
20 * strnlen+1 bytes name null terminated.
23 * total size stored in record size
25 * This code has not been tested with unicode yet.
28 #include "yaffs_nameval.h"
29 #include "yaffs_guts.h"
31 #include "yaffs_endian.h"
33 static int nval_find(struct yaffs_dev *dev,
34 const char *xb, int xb_size, const YCHAR *name,
40 memcpy(&size, xb, sizeof(size));
41 yaffs_do_endian_s32(dev, &size);
43 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
44 if (!strncmp((YCHAR *) (xb + pos + sizeof(size)),
51 if (pos < (int)(xb_size - sizeof(size))) {
52 memcpy(&size, xb + pos, sizeof(size));
53 yaffs_do_endian_s32(dev, &size);
63 static int nval_used(struct yaffs_dev *dev, const char *xb, int xb_size)
68 memcpy(&size, xb + pos, sizeof(size));
69 yaffs_do_endian_s32(dev, &size);
71 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
73 if (pos < (int)(xb_size - sizeof(size))) {
74 memcpy(&size, xb + pos, sizeof(size));
75 yaffs_do_endian_s32(dev, &size);
82 int nval_del(struct yaffs_dev *dev, char *xb, int xb_size, const YCHAR *name)
84 int pos = nval_find(dev, xb, xb_size, name, NULL);
87 if (pos < 0 || pos >= xb_size)
90 /* Find size, shift rest over this record,
91 * then zero out the rest of buffer */
92 memcpy(&size, xb + pos, sizeof(size));
93 yaffs_do_endian_s32(dev, &size);
95 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
96 memset(xb + (xb_size - size), 0, size);
100 int nval_set(struct yaffs_dev *dev,
101 char *xb, int xb_size, const YCHAR *name, const char *buf,
102 int bsize, int flags)
105 int namelen = strnlen(name, xb_size);
110 s32 reclen_endianised;
112 pos = nval_find(dev, xb, xb_size, name, &size_exist);
114 if (flags & XATTR_CREATE && pos >= 0)
116 if (flags & XATTR_REPLACE && pos < 0)
119 start = nval_used(dev, xb, xb_size);
120 space = xb_size - start + size_exist;
122 reclen = (sizeof(reclen) + namelen + 1 + bsize);
128 /* Exists, so delete it. */
129 nval_del(dev, xb, xb_size, name);
130 start = nval_used(dev, xb, xb_size);
135 reclen_endianised = reclen;
136 yaffs_do_endian_s32(dev, &reclen_endianised);
137 memcpy(xb + pos, &reclen_endianised, sizeof(reclen_endianised));
138 pos += sizeof(reclen_endianised);
139 strncpy((YCHAR *) (xb + pos), name, reclen);
140 pos += (namelen + 1);
141 memcpy(xb + pos, buf, bsize);
145 int nval_get(struct yaffs_dev *dev,
146 const char *xb, int xb_size, const YCHAR * name, char *buf,
149 int pos = nval_find(dev, xb, xb_size, name, NULL);
152 if (pos >= 0 && pos < xb_size) {
154 memcpy(&size, xb + pos, sizeof(size));
155 yaffs_do_endian_s32(dev, &size);
156 pos += sizeof(size); /* advance past record length */
157 size -= sizeof(size);
159 /* Advance over name string */
160 while (xb[pos] && size > 0 && pos < xb_size) {
164 /*Advance over NUL */
168 /* If bsize is zero then this is a size query.
169 * Return the size, but don't copy.
175 memcpy(buf, xb + pos, size);
185 int nval_list(struct yaffs_dev *dev, const char *xb, int xb_size, char *buf, int bsize)
193 memcpy(&size, xb + pos, sizeof(size));
194 yaffs_do_endian_s32(dev, &size);
196 while (size > (int)(sizeof(size)) &&
198 (pos + size) < xb_size &&
201 size -= sizeof(size);
202 name_len = strnlen((YCHAR *) (xb + pos), size);
203 if (ncopied + name_len + 1 < bsize) {
204 memcpy(buf, xb + pos, name_len * sizeof(YCHAR));
208 if (sizeof(YCHAR) > 1) {
212 ncopied += (name_len + 1);
217 if (pos < (int)(xb_size - sizeof(size))) {
218 memcpy(&size, xb + pos, sizeof(size));
219 yaffs_do_endian_s32(dev, &size);
227 int nval_hasvalues(struct yaffs_dev *dev, const char *xb, int xb_size)
229 return nval_used(dev, xb, xb_size) > 0;