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 
fdt_check_header(const void * fdt)58 int fdt_check_header(const void *fdt)
59 {
60 	if (fdt_magic(fdt) == FDT_MAGIC) {
61 		/* Complete tree */
62 		if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
63 			return -FDT_ERR_BADVERSION;
64 		if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
65 			return -FDT_ERR_BADVERSION;
66 	} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
67 		/* Unfinished sequential-write blob */
68 		if (fdt_size_dt_struct(fdt) == 0)
69 			return -FDT_ERR_BADSTATE;
70 	} else {
71 		return -FDT_ERR_BADMAGIC;
72 	}
73 
74 	return 0;
75 }
76 
fdt_offset_ptr(const void * fdt,int offset,unsigned int len)77 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
78 {
79 	const char *p;
80 
81 	if (fdt_version(fdt) >= 0x11)
82 		if (((offset + len) < offset)
83 		    || ((offset + len) > fdt_size_dt_struct(fdt)))
84 			return NULL;
85 
86 	p = _fdt_offset_ptr(fdt, offset);
87 
88 	if (p + len < p)
89 		return NULL;
90 	return p;
91 }
92 
fdt_next_tag(const void * fdt,int startoffset,int * nextoffset)93 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
94 {
95 	const fdt32_t *tagp, *lenp;
96 	uint32_t tag;
97 	int offset = startoffset;
98 	const char *p;
99 
100 	*nextoffset = -FDT_ERR_TRUNCATED;
101 	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
102 	if (!tagp)
103 		return FDT_END; /* premature end */
104 	tag = fdt32_to_cpu(*tagp);
105 	offset += FDT_TAGSIZE;
106 
107 	*nextoffset = -FDT_ERR_BADSTRUCTURE;
108 	switch (tag) {
109 	case FDT_BEGIN_NODE:
110 		/* skip name */
111 		do {
112 			p = fdt_offset_ptr(fdt, offset++, 1);
113 		} while (p && (*p != '\0'));
114 		if (!p)
115 			return FDT_END; /* premature end */
116 		break;
117 
118 	case FDT_PROP:
119 		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
120 		if (!lenp)
121 			return FDT_END; /* premature end */
122 		/* skip-name offset, length and value */
123 		offset += sizeof(struct fdt_property) - FDT_TAGSIZE
124 			+ fdt32_to_cpu(*lenp);
125 		break;
126 
127 	case FDT_END:
128 	case FDT_END_NODE:
129 	case FDT_NOP:
130 		break;
131 
132 	default:
133 		return FDT_END;
134 	}
135 
136 	if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
137 		return FDT_END; /* premature end */
138 
139 	*nextoffset = FDT_TAGALIGN(offset);
140 	return tag;
141 }
142 
_fdt_check_node_offset(const void * fdt,int offset)143 int _fdt_check_node_offset(const void *fdt, int offset)
144 {
145 	if ((offset < 0) || (offset % FDT_TAGSIZE)
146 	    || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
147 		return -FDT_ERR_BADOFFSET;
148 
149 	return offset;
150 }
151 
_fdt_check_prop_offset(const void * fdt,int offset)152 int _fdt_check_prop_offset(const void *fdt, int offset)
153 {
154 	if ((offset < 0) || (offset % FDT_TAGSIZE)
155 	    || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
156 		return -FDT_ERR_BADOFFSET;
157 
158 	return offset;
159 }
160 
fdt_next_node(const void * fdt,int offset,int * depth)161 int fdt_next_node(const void *fdt, int offset, int *depth)
162 {
163 	int nextoffset = 0;
164 	uint32_t tag;
165 
166 	if (offset >= 0)
167 		if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
168 			return nextoffset;
169 
170 	do {
171 		offset = nextoffset;
172 		tag = fdt_next_tag(fdt, offset, &nextoffset);
173 
174 		switch (tag) {
175 		case FDT_PROP:
176 		case FDT_NOP:
177 			break;
178 
179 		case FDT_BEGIN_NODE:
180 			if (depth)
181 				(*depth)++;
182 			break;
183 
184 		case FDT_END_NODE:
185 			if (depth && ((--(*depth)) < 0))
186 				return nextoffset;
187 			break;
188 
189 		case FDT_END:
190 			if ((nextoffset >= 0)
191 			    || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
192 				return -FDT_ERR_NOTFOUND;
193 			else
194 				return nextoffset;
195 		}
196 	} while (tag != FDT_BEGIN_NODE);
197 
198 	return offset;
199 }
200 
fdt_first_subnode(const void * fdt,int offset)201 int fdt_first_subnode(const void *fdt, int offset)
202 {
203 	int depth = 0;
204 
205 	offset = fdt_next_node(fdt, offset, &depth);
206 	if (offset < 0 || depth != 1)
207 		return -FDT_ERR_NOTFOUND;
208 
209 	return offset;
210 }
211 
fdt_next_subnode(const void * fdt,int offset)212 int fdt_next_subnode(const void *fdt, int offset)
213 {
214 	int depth = 1;
215 
216 	/*
217 	 * With respect to the parent, the depth of the next subnode will be
218 	 * the same as the last.
219 	 */
220 	do {
221 		offset = fdt_next_node(fdt, offset, &depth);
222 		if (offset < 0 || depth < 1)
223 			return -FDT_ERR_NOTFOUND;
224 	} while (depth > 1);
225 
226 	return offset;
227 }
228 
_fdt_find_string(const char * strtab,int tabsize,const char * s)229 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
230 {
231 	int len = strlen(s) + 1;
232 	const char *last = strtab + tabsize - len;
233 	const char *p;
234 
235 	for (p = strtab; p <= last; p++)
236 		if (memcmp(p, s, len) == 0)
237 			return p;
238 	return NULL;
239 }
240 
fdt_move(const void * fdt,void * buf,int bufsize)241 int fdt_move(const void *fdt, void *buf, int bufsize)
242 {
243 	FDT_CHECK_HEADER(fdt);
244 
245 	if (fdt_totalsize(fdt) > bufsize)
246 		return -FDT_ERR_NOSPACE;
247 
248 	memmove(buf, fdt, fdt_totalsize(fdt));
249 	return 0;
250 }
251