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
53#include <fdt.h>
54#include <libfdt.h>
55
56#include "libfdt_internal.h"
57
58/*
59 * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
60 * that the given buffer contains what appears to be a flattened
61 * device tree with sane information in its header.
62 */
63int fdt_ro_probe_(const void *fdt)
64{
65 if (fdt_magic(fdt) == FDT_MAGIC) {
66 /* Complete tree */
67 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
68 return -FDT_ERR_BADVERSION;
69 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
70 return -FDT_ERR_BADVERSION;
71 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
72 /* Unfinished sequential-write blob */
73 if (fdt_size_dt_struct(fdt) == 0)
74 return -FDT_ERR_BADSTATE;
75 } else {
76 return -FDT_ERR_BADMAGIC;
77 }
78
79 return 0;
80}
81
82static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
83{
84 return (off >= hdrsize) && (off <= totalsize);
85}
86
87static int check_block_(uint32_t hdrsize, uint32_t totalsize,
88 uint32_t base, uint32_t size)
89{
90 if (!check_off_(hdrsize, totalsize, base))
91 return 0; /* block start out of bounds */
92 if ((base + size) < base)
93 return 0; /* overflow */
94 if (!check_off_(hdrsize, totalsize, base + size))
95 return 0; /* block end out of bounds */
96 return 1;
97}
98
99size_t fdt_header_size_(uint32_t version)
100{
101 if (version <= 1)
102 return FDT_V1_SIZE;
103 else if (version <= 2)
104 return FDT_V2_SIZE;
105 else if (version <= 3)
106 return FDT_V3_SIZE;
107 else if (version <= 16)
108 return FDT_V16_SIZE;
109 else
110 return FDT_V17_SIZE;
111}
112
113int fdt_check_header(const void *fdt)
114{
115 size_t hdrsize;
116
117 if (fdt_magic(fdt) != FDT_MAGIC)
118 return -FDT_ERR_BADMAGIC;
119 hdrsize = fdt_header_size(fdt);
120 if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
121 || (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION))
122 return -FDT_ERR_BADVERSION;
123 if (fdt_version(fdt) < fdt_last_comp_version(fdt))
124 return -FDT_ERR_BADVERSION;
125
126 if ((fdt_totalsize(fdt) < hdrsize)
127 || (fdt_totalsize(fdt) > INT_MAX))
128 return -FDT_ERR_TRUNCATED;
129
130 /* Bounds check memrsv block */
131 if (!check_off_(hdrsize, fdt_totalsize(fdt), fdt_off_mem_rsvmap(fdt)))
132 return -FDT_ERR_TRUNCATED;
133
134 /* Bounds check structure block */
135 if (fdt_version(fdt) < 17) {
136 if (!check_off_(hdrsize, fdt_totalsize(fdt),
137 fdt_off_dt_struct(fdt)))
138 return -FDT_ERR_TRUNCATED;
139 } else {
140 if (!check_block_(hdrsize, fdt_totalsize(fdt),
141 fdt_off_dt_struct(fdt),
142 fdt_size_dt_struct(fdt)))
143 return -FDT_ERR_TRUNCATED;
144 }
145
146 /* Bounds check strings block */
147 if (!check_block_(hdrsize, fdt_totalsize(fdt),
148 fdt_off_dt_strings(fdt), fdt_size_dt_strings(fdt)))
149 return -FDT_ERR_TRUNCATED;
150
151 return 0;
152}
153
154const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
155{
156 unsigned absoffset = offset + fdt_off_dt_struct(fdt);
157
158 if ((absoffset < offset)
159 || ((absoffset + len) < absoffset)
160 || (absoffset + len) > fdt_totalsize(fdt))
161 return NULL;
162
163 if (fdt_version(fdt) >= 0x11)
164 if (((offset + len) < offset)
165 || ((offset + len) > fdt_size_dt_struct(fdt)))
166 return NULL;
167
168 return fdt_offset_ptr_(fdt, offset);
169}
170
171uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
172{
173 const fdt32_t *tagp, *lenp;
174 uint32_t tag;
175 int offset = startoffset;
176 const char *p;
177
178 *nextoffset = -FDT_ERR_TRUNCATED;
179 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
180 if (!tagp)
181 return FDT_END; /* premature end */
182 tag = fdt32_to_cpu(*tagp);
183 offset += FDT_TAGSIZE;
184
185 *nextoffset = -FDT_ERR_BADSTRUCTURE;
186 switch (tag) {
187 case FDT_BEGIN_NODE:
188 /* skip name */
189 do {
190 p = fdt_offset_ptr(fdt, offset++, 1);
191 } while (p && (*p != '\0'));
192 if (!p)
193 return FDT_END; /* premature end */
194 break;
195
196 case FDT_PROP:
197 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
198 if (!lenp)
199 return FDT_END; /* premature end */
200 /* skip-name offset, length and value */
201 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
202 + fdt32_to_cpu(*lenp);
203 if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
204 ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
205 offset += 4;
206 break;
207
208 case FDT_END:
209 case FDT_END_NODE:
210 case FDT_NOP:
211 break;
212
213 default:
214 return FDT_END;
215 }
216
217 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
218 return FDT_END; /* premature end */
219
220 *nextoffset = FDT_TAGALIGN(offset);
221 return tag;
222}
223
224int fdt_check_node_offset_(const void *fdt, int offset)
225{
226 if ((offset < 0) || (offset % FDT_TAGSIZE)
227 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
228 return -FDT_ERR_BADOFFSET;
229
230 return offset;
231}
232
233int fdt_check_prop_offset_(const void *fdt, int offset)
234{
235 if ((offset < 0) || (offset % FDT_TAGSIZE)
236 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
237 return -FDT_ERR_BADOFFSET;
238
239 return offset;
240}
241
242int fdt_next_node(const void *fdt, int offset, int *depth)
243{
244 int nextoffset = 0;
245 uint32_t tag;
246
247 if (offset >= 0)
248 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
249 return nextoffset;
250
251 do {
252 offset = nextoffset;
253 tag = fdt_next_tag(fdt, offset, &nextoffset);
254
255 switch (tag) {
256 case FDT_PROP:
257 case FDT_NOP:
258 break;
259
260 case FDT_BEGIN_NODE:
261 if (depth)
262 (*depth)++;
263 break;
264
265 case FDT_END_NODE:
266 if (depth && ((--(*depth)) < 0))
267 return nextoffset;
268 break;
269
270 case FDT_END:
271 if ((nextoffset >= 0)
272 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
273 return -FDT_ERR_NOTFOUND;
274 else
275 return nextoffset;
276 }
277 } while (tag != FDT_BEGIN_NODE);
278
279 return offset;
280}
281
282int fdt_first_subnode(const void *fdt, int offset)
283{
284 int depth = 0;
285
286 offset = fdt_next_node(fdt, offset, &depth);
287 if (offset < 0 || depth != 1)
288 return -FDT_ERR_NOTFOUND;
289
290 return offset;
291}
292
293int fdt_next_subnode(const void *fdt, int offset)
294{
295 int depth = 1;
296
297 /*
298 * With respect to the parent, the depth of the next subnode will be
299 * the same as the last.
300 */
301 do {
302 offset = fdt_next_node(fdt, offset, &depth);
303 if (offset < 0 || depth < 1)
304 return -FDT_ERR_NOTFOUND;
305 } while (depth > 1);
306
307 return offset;
308}
309
310const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
311{
312 int len = strlen(s) + 1;
313 const char *last = strtab + tabsize - len;
314 const char *p;
315
316 for (p = strtab; p <= last; p++)
317 if (memcmp(p, s, len) == 0)
318 return p;
319 return NULL;
320}
321
322int fdt_move(const void *fdt, void *buf, int bufsize)
323{
324 FDT_RO_PROBE(fdt);
325
326 if (fdt_totalsize(fdt) > bufsize)
327 return -FDT_ERR_NOSPACE;
328
329 memmove(buf, fdt, fdt_totalsize(fdt));
330 return 0;
331}
332