1 // SPDX-License-Identifier: (BSD-2-Clause OR GPL-2.0+) 2 /* 3 * libfdt - Flat Device Tree manipulation 4 * Copyright (C) 2006 David Gibson, IBM Corporation. 5 * 6 * libfdt is dual licensed: you can use it either under the terms of 7 * the GPL, or the BSD license, at your option. 8 * 9 * a) This library is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License as 11 * published by the Free Software Foundation; either version 2 of the 12 * License, or (at your option) any later version. 13 * 14 * This library is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public 20 * License along with this library; if not, write to the Free 21 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, 22 * MA 02110-1301 USA 23 * 24 * Alternatively, 25 * 26 * b) Redistribution and use in source and binary forms, with or 27 * without modification, are permitted provided that the following 28 * conditions are met: 29 * 30 * 1. Redistributions of source code must retain the above 31 * copyright notice, this list of conditions and the following 32 * disclaimer. 33 * 2. Redistributions in binary form must reproduce the above 34 * copyright notice, this list of conditions and the following 35 * disclaimer in the documentation and/or other materials 36 * provided with the distribution. 37 * 38 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 39 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 40 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 41 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 42 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 43 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 48 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 49 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 50 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 51 */ 52 #include "libfdt_env.h" 53 54 #include <fdt.h> 55 #include <libfdt.h> 56 57 #include "libfdt_internal.h" 58 59 int fdt_check_header(const void *fdt) 60 { 61 if (fdt_magic(fdt) == FDT_MAGIC) { 62 /* Complete tree */ 63 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION) 64 return -FDT_ERR_BADVERSION; 65 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION) 66 return -FDT_ERR_BADVERSION; 67 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) { 68 /* Unfinished sequential-write blob */ 69 if (fdt_size_dt_struct(fdt) == 0) 70 return -FDT_ERR_BADSTATE; 71 } else { 72 return -FDT_ERR_BADMAGIC; 73 } 74 75 return 0; 76 } 77 78 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len) 79 { 80 unsigned absoffset = offset + fdt_off_dt_struct(fdt); 81 82 if ((absoffset < offset) 83 || ((absoffset + len) < absoffset) 84 || (absoffset + len) > fdt_totalsize(fdt)) 85 return NULL; 86 87 if (fdt_version(fdt) >= 0x11) 88 if (((offset + len) < offset) 89 || ((offset + len) > fdt_size_dt_struct(fdt))) 90 return NULL; 91 92 return fdt_offset_ptr_(fdt, offset); 93 } 94 95 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset) 96 { 97 const fdt32_t *tagp, *lenp; 98 uint32_t tag; 99 int offset = startoffset; 100 const char *p; 101 102 *nextoffset = -FDT_ERR_TRUNCATED; 103 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE); 104 if (!tagp) 105 return FDT_END; /* premature end */ 106 tag = fdt32_to_cpu(*tagp); 107 offset += FDT_TAGSIZE; 108 109 *nextoffset = -FDT_ERR_BADSTRUCTURE; 110 switch (tag) { 111 case FDT_BEGIN_NODE: 112 /* skip name */ 113 do { 114 p = fdt_offset_ptr(fdt, offset++, 1); 115 } while (p && (*p != '\0')); 116 if (!p) 117 return FDT_END; /* premature end */ 118 break; 119 120 case FDT_PROP: 121 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp)); 122 if (!lenp) 123 return FDT_END; /* premature end */ 124 /* skip-name offset, length and value */ 125 offset += sizeof(struct fdt_property) - FDT_TAGSIZE 126 + fdt32_to_cpu(*lenp); 127 if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 && 128 ((offset - fdt32_to_cpu(*lenp)) % 8) != 0) 129 offset += 4; 130 break; 131 132 case FDT_END: 133 case FDT_END_NODE: 134 case FDT_NOP: 135 break; 136 137 default: 138 return FDT_END; 139 } 140 141 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset)) 142 return FDT_END; /* premature end */ 143 144 *nextoffset = FDT_TAGALIGN(offset); 145 return tag; 146 } 147 148 int fdt_check_node_offset_(const void *fdt, int offset) 149 { 150 if ((offset < 0) || (offset % FDT_TAGSIZE) 151 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)) 152 return -FDT_ERR_BADOFFSET; 153 154 return offset; 155 } 156 157 int fdt_check_prop_offset_(const void *fdt, int offset) 158 { 159 if ((offset < 0) || (offset % FDT_TAGSIZE) 160 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)) 161 return -FDT_ERR_BADOFFSET; 162 163 return offset; 164 } 165 166 int fdt_next_node(const void *fdt, int offset, int *depth) 167 { 168 int nextoffset = 0; 169 uint32_t tag; 170 171 if (offset >= 0) 172 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0) 173 return nextoffset; 174 175 do { 176 offset = nextoffset; 177 tag = fdt_next_tag(fdt, offset, &nextoffset); 178 179 switch (tag) { 180 case FDT_PROP: 181 case FDT_NOP: 182 break; 183 184 case FDT_BEGIN_NODE: 185 if (depth) 186 (*depth)++; 187 break; 188 189 case FDT_END_NODE: 190 if (depth && ((--(*depth)) < 0)) 191 return nextoffset; 192 break; 193 194 case FDT_END: 195 if ((nextoffset >= 0) 196 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth)) 197 return -FDT_ERR_NOTFOUND; 198 else 199 return nextoffset; 200 } 201 } while (tag != FDT_BEGIN_NODE); 202 203 return offset; 204 } 205 206 int fdt_first_subnode(const void *fdt, int offset) 207 { 208 int depth = 0; 209 210 offset = fdt_next_node(fdt, offset, &depth); 211 if (offset < 0 || depth != 1) 212 return -FDT_ERR_NOTFOUND; 213 214 return offset; 215 } 216 217 int fdt_next_subnode(const void *fdt, int offset) 218 { 219 int depth = 1; 220 221 /* 222 * With respect to the parent, the depth of the next subnode will be 223 * the same as the last. 224 */ 225 do { 226 offset = fdt_next_node(fdt, offset, &depth); 227 if (offset < 0 || depth < 1) 228 return -FDT_ERR_NOTFOUND; 229 } while (depth > 1); 230 231 return offset; 232 } 233 234 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s) 235 { 236 int len = strlen(s) + 1; 237 const char *last = strtab + tabsize - len; 238 const char *p; 239 240 for (p = strtab; p <= last; p++) 241 if (memcmp(p, s, len) == 0) 242 return p; 243 return NULL; 244 } 245 246 int fdt_move(const void *fdt, void *buf, int bufsize) 247 { 248 FDT_CHECK_HEADER(fdt); 249 250 if (fdt_totalsize(fdt) > bufsize) 251 return -FDT_ERR_NOSPACE; 252 253 memmove(buf, fdt, fdt_totalsize(fdt)); 254 return 0; 255 } 256