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 if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 && 127 ((offset - fdt32_to_cpu(*lenp)) % 8) != 0) 128 offset += 4; 129 break; 130 131 case FDT_END: 132 case FDT_END_NODE: 133 case FDT_NOP: 134 break; 135 136 default: 137 return FDT_END; 138 } 139 140 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset)) 141 return FDT_END; /* premature end */ 142 143 *nextoffset = FDT_TAGALIGN(offset); 144 return tag; 145 } 146 147 int fdt_check_node_offset_(const void *fdt, int offset) 148 { 149 if ((offset < 0) || (offset % FDT_TAGSIZE) 150 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)) 151 return -FDT_ERR_BADOFFSET; 152 153 return offset; 154 } 155 156 int fdt_check_prop_offset_(const void *fdt, int offset) 157 { 158 if ((offset < 0) || (offset % FDT_TAGSIZE) 159 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)) 160 return -FDT_ERR_BADOFFSET; 161 162 return offset; 163 } 164 165 int fdt_next_node(const void *fdt, int offset, int *depth) 166 { 167 int nextoffset = 0; 168 uint32_t tag; 169 170 if (offset >= 0) 171 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0) 172 return nextoffset; 173 174 do { 175 offset = nextoffset; 176 tag = fdt_next_tag(fdt, offset, &nextoffset); 177 178 switch (tag) { 179 case FDT_PROP: 180 case FDT_NOP: 181 break; 182 183 case FDT_BEGIN_NODE: 184 if (depth) 185 (*depth)++; 186 break; 187 188 case FDT_END_NODE: 189 if (depth && ((--(*depth)) < 0)) 190 return nextoffset; 191 break; 192 193 case FDT_END: 194 if ((nextoffset >= 0) 195 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth)) 196 return -FDT_ERR_NOTFOUND; 197 else 198 return nextoffset; 199 } 200 } while (tag != FDT_BEGIN_NODE); 201 202 return offset; 203 } 204 205 int fdt_first_subnode(const void *fdt, int offset) 206 { 207 int depth = 0; 208 209 offset = fdt_next_node(fdt, offset, &depth); 210 if (offset < 0 || depth != 1) 211 return -FDT_ERR_NOTFOUND; 212 213 return offset; 214 } 215 216 int fdt_next_subnode(const void *fdt, int offset) 217 { 218 int depth = 1; 219 220 /* 221 * With respect to the parent, the depth of the next subnode will be 222 * the same as the last. 223 */ 224 do { 225 offset = fdt_next_node(fdt, offset, &depth); 226 if (offset < 0 || depth < 1) 227 return -FDT_ERR_NOTFOUND; 228 } while (depth > 1); 229 230 return offset; 231 } 232 233 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s) 234 { 235 int len = strlen(s) + 1; 236 const char *last = strtab + tabsize - len; 237 const char *p; 238 239 for (p = strtab; p <= last; p++) 240 if (memcmp(p, s, len) == 0) 241 return p; 242 return NULL; 243 } 244 245 int fdt_move(const void *fdt, void *buf, int bufsize) 246 { 247 FDT_CHECK_HEADER(fdt); 248 249 if (fdt_totalsize(fdt) > bufsize) 250 return -FDT_ERR_NOSPACE; 251 252 memmove(buf, fdt, fdt_totalsize(fdt)); 253 return 0; 254 } 255