1 /*
2 * libfdt - Flat Device Tree manipulation
3 * Copyright (C) 2006 David Gibson, IBM Corporation.
4 *
5 * libfdt is dual licensed: you can use it either under the terms of
6 * the GPL, or the BSD license, at your option.
7 *
8 * a) This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public
19 * License along with this library; if not, write to the Free
20 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
21 * MA 02110-1301 USA
22 *
23 * Alternatively,
24 *
25 * b) Redistribution and use in source and binary forms, with or
26 * without modification, are permitted provided that the following
27 * conditions are met:
28 *
29 * 1. Redistributions of source code must retain the above
30 * copyright notice, this list of conditions and the following
31 * disclaimer.
32 * 2. Redistributions in binary form must reproduce the above
33 * copyright notice, this list of conditions and the following
34 * disclaimer in the documentation and/or other materials
35 * provided with the distribution.
36 *
37 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
38 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
39 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
40 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
41 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
42 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
47 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
48 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
49 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
50 */
51 #include "libfdt_env.h"
52 #include "fdt.h"
53 #include "libfdt.h"
54 #include "libfdt_internal.h"
55
fdt_check_header(const void * fdt)56 int fdt_check_header(const void *fdt)
57 {
58 if (fdt_magic(fdt) == FDT_MAGIC) {
59 /* Complete tree */
60 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
61 return -FDT_ERR_BADVERSION;
62 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
63 return -FDT_ERR_BADVERSION;
64 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
65 /* Unfinished sequential-write blob */
66 if (fdt_size_dt_struct(fdt) == 0)
67 return -FDT_ERR_BADSTATE;
68 } else {
69 return -FDT_ERR_BADMAGIC;
70 }
71
72 return 0;
73 }
74
fdt_offset_ptr(const void * fdt,int offset,unsigned int len)75 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
76 {
77 unsigned absoffset = offset + fdt_off_dt_struct(fdt);
78
79 if ((absoffset < offset)
80 || ((absoffset + len) < absoffset)
81 || (absoffset + len) > fdt_totalsize(fdt))
82 return NULL;
83
84 if (fdt_version(fdt) >= 0x11)
85 if (((offset + len) < offset)
86 || ((offset + len) > fdt_size_dt_struct(fdt)))
87 return NULL;
88
89 return _fdt_offset_ptr(fdt, offset);
90 }
91
fdt_next_tag(const void * fdt,int startoffset,int * nextoffset)92 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
93 {
94 const fdt32_t *tagp, *lenp;
95 uint32_t tag;
96 int offset = startoffset;
97 const char *p;
98
99 *nextoffset = -FDT_ERR_TRUNCATED;
100 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
101 if (!tagp)
102 return FDT_END; /* premature end */
103 tag = fdt32_to_cpu(*tagp);
104 offset += FDT_TAGSIZE;
105
106 *nextoffset = -FDT_ERR_BADSTRUCTURE;
107 switch (tag) {
108 case FDT_BEGIN_NODE:
109 /* skip name */
110 do {
111 p = fdt_offset_ptr(fdt, offset++, 1);
112 } while (p && (*p != '\0'));
113 if (!p)
114 return FDT_END; /* premature end */
115 break;
116
117 case FDT_PROP:
118 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
119 if (!lenp)
120 return FDT_END; /* premature end */
121 /* skip-name offset, length and value */
122 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
123 + fdt32_to_cpu(*lenp);
124 break;
125
126 case FDT_END:
127 case FDT_END_NODE:
128 case FDT_NOP:
129 break;
130
131 default:
132 return FDT_END;
133 }
134
135 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
136 return FDT_END; /* premature end */
137
138 *nextoffset = FDT_TAGALIGN(offset);
139 return tag;
140 }
141
_fdt_check_node_offset(const void * fdt,int offset)142 int _fdt_check_node_offset(const void *fdt, int offset)
143 {
144 if ((offset < 0) || (offset % FDT_TAGSIZE)
145 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
146 return -FDT_ERR_BADOFFSET;
147
148 return offset;
149 }
150
_fdt_check_prop_offset(const void * fdt,int offset)151 int _fdt_check_prop_offset(const void *fdt, int offset)
152 {
153 if ((offset < 0) || (offset % FDT_TAGSIZE)
154 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
155 return -FDT_ERR_BADOFFSET;
156
157 return offset;
158 }
159
fdt_next_node(const void * fdt,int offset,int * depth)160 int fdt_next_node(const void *fdt, int offset, int *depth)
161 {
162 int nextoffset = 0;
163 uint32_t tag;
164
165 if (offset >= 0)
166 if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
167 return nextoffset;
168
169 do {
170 offset = nextoffset;
171 tag = fdt_next_tag(fdt, offset, &nextoffset);
172
173 switch (tag) {
174 case FDT_PROP:
175 case FDT_NOP:
176 break;
177
178 case FDT_BEGIN_NODE:
179 if (depth)
180 (*depth)++;
181 break;
182
183 case FDT_END_NODE:
184 if (depth && ((--(*depth)) < 0))
185 return nextoffset;
186 break;
187
188 case FDT_END:
189 if ((nextoffset >= 0)
190 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
191 return -FDT_ERR_NOTFOUND;
192 else
193 return nextoffset;
194 }
195 } while (tag != FDT_BEGIN_NODE);
196
197 return offset;
198 }
199
fdt_first_subnode(const void * fdt,int offset)200 int fdt_first_subnode(const void *fdt, int offset)
201 {
202 int depth = 0;
203
204 offset = fdt_next_node(fdt, offset, &depth);
205 if (offset < 0 || depth != 1)
206 return -FDT_ERR_NOTFOUND;
207
208 return offset;
209 }
210
fdt_next_subnode(const void * fdt,int offset)211 int fdt_next_subnode(const void *fdt, int offset)
212 {
213 int depth = 1;
214
215 /*
216 * With respect to the parent, the depth of the next subnode will be
217 * the same as the last.
218 */
219 do {
220 offset = fdt_next_node(fdt, offset, &depth);
221 if (offset < 0 || depth < 1)
222 return -FDT_ERR_NOTFOUND;
223 } while (depth > 1);
224
225 return offset;
226 }
227
_fdt_find_string(const char * strtab,int tabsize,const char * s)228 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
229 {
230 int len = strlen(s) + 1;
231 const char *last = strtab + tabsize - len;
232 const char *p;
233
234 for (p = strtab; p <= last; p++)
235 if (memcmp(p, s, len) == 0)
236 return p;
237 return NULL;
238 }
239
fdt_move(const void * fdt,void * buf,int bufsize)240 int fdt_move(const void *fdt, void *buf, int bufsize)
241 {
242 FDT_CHECK_HEADER(fdt);
243
244 if (fdt_totalsize(fdt) > bufsize)
245 return -FDT_ERR_NOSPACE;
246
247 memmove(buf, fdt, fdt_totalsize(fdt));
248 return 0;
249 }
250