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 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 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 } 142 143 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 } 151 152 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 } 160 161 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 } 200 201 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 } 211 212 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 } 228 229 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 } 240 241 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