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-rw-r--r--fs/yaffs2/yaffs_nameval.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/fs/yaffs2/yaffs_nameval.c b/fs/yaffs2/yaffs_nameval.c
new file mode 100644
index 00000000000..daa36f989d3
--- /dev/null
+++ b/fs/yaffs2/yaffs_nameval.c
@@ -0,0 +1,201 @@
1/*
2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3 *
4 * Copyright (C) 2002-2010 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
6 *
7 * Created by Charles Manning <charles@aleph1.co.uk>
8 *
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.
12 */
13
14/*
15 * This simple implementation of a name-value store assumes a small number of values and fits
16 * into a small finite buffer.
17 *
18 * Each attribute is stored as a record:
19 * sizeof(int) bytes record size.
20 * strnlen+1 bytes name null terminated.
21 * nbytes value.
22 * ----------
23 * total size stored in record size
24 *
25 * This code has not been tested with unicode yet.
26 */
27
28#include "yaffs_nameval.h"
29
30#include "yportenv.h"
31
32static int nval_find(const char *xb, int xb_size, const YCHAR * name,
33 int *exist_size)
34{
35 int pos = 0;
36 int size;
37
38 memcpy(&size, xb, sizeof(int));
39 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
40 if (strncmp
41 ((YCHAR *) (xb + pos + sizeof(int)), name, size) == 0) {
42 if (exist_size)
43 *exist_size = size;
44 return pos;
45 }
46 pos += size;
47 if (pos < xb_size - sizeof(int))
48 memcpy(&size, xb + pos, sizeof(int));
49 else
50 size = 0;
51 }
52 if (exist_size)
53 *exist_size = 0;
54 return -1;
55}
56
57static int nval_used(const char *xb, int xb_size)
58{
59 int pos = 0;
60 int size;
61
62 memcpy(&size, xb + pos, sizeof(int));
63 while (size > 0 && (size < xb_size) && (pos + size < xb_size)) {
64 pos += size;
65 if (pos < xb_size - sizeof(int))
66 memcpy(&size, xb + pos, sizeof(int));
67 else
68 size = 0;
69 }
70 return pos;
71}
72
73int nval_del(char *xb, int xb_size, const YCHAR * name)
74{
75 int pos = nval_find(xb, xb_size, name, NULL);
76 int size;
77
78 if (pos >= 0 && pos < xb_size) {
79 /* Find size, shift rest over this record, then zero out the rest of buffer */
80 memcpy(&size, xb + pos, sizeof(int));
81 memcpy(xb + pos, xb + pos + size, xb_size - (pos + size));
82 memset(xb + (xb_size - size), 0, size);
83 return 0;
84 } else {
85 return -ENODATA;
86 }
87}
88
89int nval_set(char *xb, int xb_size, const YCHAR * name, const char *buf,
90 int bsize, int flags)
91{
92 int pos;
93 int namelen = strnlen(name, xb_size);
94 int reclen;
95 int size_exist = 0;
96 int space;
97 int start;
98
99 pos = nval_find(xb, xb_size, name, &size_exist);
100
101 if (flags & XATTR_CREATE && pos >= 0)
102 return -EEXIST;
103 if (flags & XATTR_REPLACE && pos < 0)
104 return -ENODATA;
105
106 start = nval_used(xb, xb_size);
107 space = xb_size - start + size_exist;
108
109 reclen = (sizeof(int) + namelen + 1 + bsize);
110
111 if (reclen > space)
112 return -ENOSPC;
113
114 if (pos >= 0) {
115 nval_del(xb, xb_size, name);
116 start = nval_used(xb, xb_size);
117 }
118
119 pos = start;
120
121 memcpy(xb + pos, &reclen, sizeof(int));
122 pos += sizeof(int);
123 strncpy((YCHAR *) (xb + pos), name, reclen);
124 pos += (namelen + 1);
125 memcpy(xb + pos, buf, bsize);
126 return 0;
127}
128
129int nval_get(const char *xb, int xb_size, const YCHAR * name, char *buf,
130 int bsize)
131{
132 int pos = nval_find(xb, xb_size, name, NULL);
133 int size;
134
135 if (pos >= 0 && pos < xb_size) {
136
137 memcpy(&size, xb + pos, sizeof(int));
138 pos += sizeof(int); /* advance past record length */
139 size -= sizeof(int);
140
141 /* Advance over name string */
142 while (xb[pos] && size > 0 && pos < xb_size) {
143 pos++;
144 size--;
145 }
146 /*Advance over NUL */
147 pos++;
148 size--;
149
150 if (size <= bsize) {
151 memcpy(buf, xb + pos, size);
152 return size;
153 }
154
155 }
156 if (pos >= 0)
157 return -ERANGE;
158 else
159 return -ENODATA;
160}
161
162int nval_list(const char *xb, int xb_size, char *buf, int bsize)
163{
164 int pos = 0;
165 int size;
166 int name_len;
167 int ncopied = 0;
168 int filled = 0;
169
170 memcpy(&size, xb + pos, sizeof(int));
171 while (size > sizeof(int) && size <= xb_size && (pos + size) < xb_size
172 && !filled) {
173 pos += sizeof(int);
174 size -= sizeof(int);
175 name_len = strnlen((YCHAR *) (xb + pos), size);
176 if (ncopied + name_len + 1 < bsize) {
177 memcpy(buf, xb + pos, name_len * sizeof(YCHAR));
178 buf += name_len;
179 *buf = '\0';
180 buf++;
181 if (sizeof(YCHAR) > 1) {
182 *buf = '\0';
183 buf++;
184 }
185 ncopied += (name_len + 1);
186 } else {
187 filled = 1;
188 }
189 pos += size;
190 if (pos < xb_size - sizeof(int))
191 memcpy(&size, xb + pos, sizeof(int));
192 else
193 size = 0;
194 }
195 return ncopied;
196}
197
198int nval_hasvalues(const char *xb, int xb_size)
199{
200 return nval_used(xb, xb_size) > 0;
201}
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