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 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 77 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len) 78 { 79 unsigned absoffset = offset + fdt_off_dt_struct(fdt); 80 81 if ((absoffset < offset) 82 || ((absoffset + len) < absoffset) 83 || (absoffset + len) > fdt_totalsize(fdt)) 84 return NULL; 85 86 if (fdt_version(fdt) >= 0x11) 87 if (((offset + len) < offset) 88 || ((offset + len) > fdt_size_dt_struct(fdt))) 89 return NULL; 90 91 return _fdt_offset_ptr(fdt, offset); 92 } 93 94 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset) 95 { 96 const fdt32_t *tagp, *lenp; 97 uint32_t tag; 98 int offset = startoffset; 99 const char *p; 100 101 *nextoffset = -FDT_ERR_TRUNCATED; 102 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE); 103 if (!tagp) 104 return FDT_END; /* premature end */ 105 tag = fdt32_to_cpu(*tagp); 106 offset += FDT_TAGSIZE; 107 108 *nextoffset = -FDT_ERR_BADSTRUCTURE; 109 switch (tag) { 110 case FDT_BEGIN_NODE: 111 /* skip name */ 112 do { 113 p = fdt_offset_ptr(fdt, offset++, 1); 114 } while (p && (*p != '\0')); 115 if (!p) 116 return FDT_END; /* premature end */ 117 break; 118 119 case FDT_PROP: 120 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp)); 121 if (!lenp) 122 return FDT_END; /* premature end */ 123 /* skip-name offset, length and value */ 124 offset += sizeof(struct fdt_property) - FDT_TAGSIZE 125 + fdt32_to_cpu(*lenp); 126 break; 127 128 case FDT_END: 129 case FDT_END_NODE: 130 case FDT_NOP: 131 break; 132 133 default: 134 return FDT_END; 135 } 136 137 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset)) 138 return FDT_END; /* premature end */ 139 140 *nextoffset = FDT_TAGALIGN(offset); 141 return tag; 142 } 143 144 int _fdt_check_node_offset(const void *fdt, int offset) 145 { 146 if ((offset < 0) || (offset % FDT_TAGSIZE) 147 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)) 148 return -FDT_ERR_BADOFFSET; 149 150 return offset; 151 } 152 153 int _fdt_check_prop_offset(const void *fdt, int offset) 154 { 155 if ((offset < 0) || (offset % FDT_TAGSIZE) 156 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)) 157 return -FDT_ERR_BADOFFSET; 158 159 return offset; 160 } 161 162 int fdt_next_node(const void *fdt, int offset, int *depth) 163 { 164 int nextoffset = 0; 165 uint32_t tag; 166 167 if (offset >= 0) 168 if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0) 169 return nextoffset; 170 171 do { 172 offset = nextoffset; 173 tag = fdt_next_tag(fdt, offset, &nextoffset); 174 175 switch (tag) { 176 case FDT_PROP: 177 case FDT_NOP: 178 break; 179 180 case FDT_BEGIN_NODE: 181 if (depth) 182 (*depth)++; 183 break; 184 185 case FDT_END_NODE: 186 if (depth && ((--(*depth)) < 0)) 187 return nextoffset; 188 break; 189 190 case FDT_END: 191 if ((nextoffset >= 0) 192 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth)) 193 return -FDT_ERR_NOTFOUND; 194 else 195 return nextoffset; 196 } 197 } while (tag != FDT_BEGIN_NODE); 198 199 return offset; 200 } 201 202 int fdt_first_subnode(const void *fdt, int offset) 203 { 204 int depth = 0; 205 206 offset = fdt_next_node(fdt, offset, &depth); 207 if (offset < 0 || depth != 1) 208 return -FDT_ERR_NOTFOUND; 209 210 return offset; 211 } 212 213 int fdt_next_subnode(const void *fdt, int offset) 214 { 215 int depth = 1; 216 217 /* 218 * With respect to the parent, the depth of the next subnode will be 219 * the same as the last. 220 */ 221 do { 222 offset = fdt_next_node(fdt, offset, &depth); 223 if (offset < 0 || depth < 1) 224 return -FDT_ERR_NOTFOUND; 225 } while (depth > 1); 226 227 return offset; 228 } 229 230 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s) 231 { 232 int len = strlen(s) + 1; 233 const char *last = strtab + tabsize - len; 234 const char *p; 235 236 for (p = strtab; p <= last; p++) 237 if (memcmp(p, s, len) == 0) 238 return p; 239 return NULL; 240 } 241 242 int fdt_move(const void *fdt, void *buf, int bufsize) 243 { 244 FDT_CHECK_HEADER(fdt); 245 246 if (fdt_totalsize(fdt) > bufsize) 247 return -FDT_ERR_NOSPACE; 248 249 memmove(buf, fdt, fdt_totalsize(fdt)); 250 return 0; 251 } 252