2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
4 * Copyright (C) 2002-2018 Aleph One Ltd.
6 * Created by Charles Manning <charles@aleph1.co.uk>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
14 * This simple implementation of a name-value store assumes a small number of
15 * values and fits into a small finite buffer.
17 * Each attribute is stored as a record:
18 * sizeof(size) bytes record size.
19 * strnlen+1 bytes name null terminated.
22 * total size stored in record size
24 * This code has not been tested with unicode yet.
27 #include "yaffs_nameval.h"
28 #include "yaffs_guts.h"
30 #include "yaffs_endian.h"
32 static int nval_find(struct yaffs_dev *dev,
33 const char *xb, int xb_size, const YCHAR *name,
39 memcpy(&size, xb, sizeof(size));
40 yaffs_do_endian_s32(dev, &size);
42 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
43 if (!strncmp((YCHAR *) (xb + pos + sizeof(size)),
50 if (pos < (int)(xb_size - sizeof(size))) {
51 memcpy(&size, xb + pos, sizeof(size));
52 yaffs_do_endian_s32(dev, &size);
62 static int nval_used(struct yaffs_dev *dev, const char *xb, int xb_size)
67 memcpy(&size, xb + pos, sizeof(size));
68 yaffs_do_endian_s32(dev, &size);
70 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
72 if (pos < (int)(xb_size - sizeof(size))) {
73 memcpy(&size, xb + pos, sizeof(size));
74 yaffs_do_endian_s32(dev, &size);
81 int nval_del(struct yaffs_dev *dev, char *xb, int xb_size, const YCHAR *name)
83 int pos = nval_find(dev, xb, xb_size, name, NULL);
86 if (pos < 0 || pos >= xb_size)
89 /* Find size, shift rest over this record,
90 * then zero out the rest of buffer */
91 memcpy(&size, xb + pos, sizeof(size));
92 yaffs_do_endian_s32(dev, &size);
94 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
95 memset(xb + (xb_size - size), 0, size);
99 int nval_set(struct yaffs_dev *dev,
100 char *xb, int xb_size, const YCHAR *name, const char *buf,
101 int bsize, int flags)
104 int namelen = strnlen(name, xb_size);
109 s32 reclen_endianised;
111 pos = nval_find(dev, xb, xb_size, name, &size_exist);
113 if (flags & XATTR_CREATE && pos >= 0)
115 if (flags & XATTR_REPLACE && pos < 0)
118 start = nval_used(dev, xb, xb_size);
119 space = xb_size - start + size_exist;
121 reclen = (sizeof(reclen) + namelen + 1 + bsize);
127 /* Exists, so delete it. */
128 nval_del(dev, xb, xb_size, name);
129 start = nval_used(dev, xb, xb_size);
134 reclen_endianised = reclen;
135 yaffs_do_endian_s32(dev, &reclen_endianised);
136 memcpy(xb + pos, &reclen_endianised, sizeof(reclen_endianised));
137 pos += sizeof(reclen_endianised);
138 strncpy((YCHAR *) (xb + pos), name, reclen);
139 pos += (namelen + 1);
140 memcpy(xb + pos, buf, bsize);
144 int nval_get(struct yaffs_dev *dev,
145 const char *xb, int xb_size, const YCHAR * name, char *buf,
148 int pos = nval_find(dev, xb, xb_size, name, NULL);
151 if (pos >= 0 && pos < xb_size) {
153 memcpy(&size, xb + pos, sizeof(size));
154 yaffs_do_endian_s32(dev, &size);
155 pos += sizeof(size); /* advance past record length */
156 size -= sizeof(size);
158 /* Advance over name string */
159 while (xb[pos] && size > 0 && pos < xb_size) {
163 /*Advance over NUL */
167 /* If bsize is zero then this is a size query.
168 * Return the size, but don't copy.
174 memcpy(buf, xb + pos, size);
184 int nval_list(struct yaffs_dev *dev, const char *xb, int xb_size, char *buf, int bsize)
192 memcpy(&size, xb + pos, sizeof(size));
193 yaffs_do_endian_s32(dev, &size);
195 while (size > (int)(sizeof(size)) &&
197 (pos + size) < xb_size &&
200 size -= sizeof(size);
201 name_len = strnlen((YCHAR *) (xb + pos), size);
202 if (ncopied + name_len + 1 < bsize) {
203 memcpy(buf, xb + pos, name_len * sizeof(YCHAR));
207 if (sizeof(YCHAR) > 1) {
211 ncopied += (name_len + 1);
216 if (pos < (int)(xb_size - sizeof(size))) {
217 memcpy(&size, xb + pos, sizeof(size));
218 yaffs_do_endian_s32(dev, &size);
226 int nval_hasvalues(struct yaffs_dev *dev, const char *xb, int xb_size)
228 return nval_used(dev, xb, xb_size) > 0;