ext/libfdt/fdt.c

   1 /*
   2  * libfdt - Flat Device Tree manipulation
   3  * Copyright (C) 2006 David Gibson, IBM Corporation.
   4  *
   5  *     Redistribution and use in source and binary forms, with or
   6  *     without modification, are permitted provided that the following
   7  *     conditions are met:
   8  *
   9  *     1. Redistributions of source code must retain the above
  10  *        copyright notice, this list of conditions and the following
  11  *        disclaimer.
  12  *     2. Redistributions in binary form must reproduce the above
  13  *        copyright notice, this list of conditions and the following
  14  *        disclaimer in the documentation and/or other materials
  15  *        provided with the distribution.
  16  *
  17  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  18  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  19  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  20  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  22  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  28  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  29  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 #include <fdt.h>
  32 #include <libfdt.h>
  33
  34 #include "libfdt_env.h"
  35 #include "libfdt_internal.h"
  36
  37 int fdt_check_header(const void *fdt)
  38 {
  39         if (fdt_magic(fdt) == FDT_MAGIC) {
  40                 /* Complete tree */
  41                 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  42                         return -FDT_ERR_BADVERSION;
  43                 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
  44                         return -FDT_ERR_BADVERSION;
  45         } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
  46                 /* Unfinished sequential-write blob */
  47                 if (fdt_size_dt_struct(fdt) == 0)
  48                         return -FDT_ERR_BADSTATE;
  49         } else {
  50                 return -FDT_ERR_BADMAGIC;
  51         }
  52
  53         return 0;
  54 }
  55
  56 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
  57 {
  58         const char *p;
  59
  60         if (fdt_version(fdt) >= 0x11)
  61                 if (((offset + len) < offset)
  62                     || ((offset + len) > fdt_size_dt_struct(fdt)))
  63                         return NULL;
  64
  65         p = _fdt_offset_ptr(fdt, offset);
  66
  67         if (p + len < p)
  68                 return NULL;
  69         return p;
  70 }
  71
  72 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
  73 {
  74         const fdt32_t *tagp, *lenp;
  75         uint32_t tag;
  76         int offset = startoffset;
  77         const char *p;
  78
  79         *nextoffset = -FDT_ERR_TRUNCATED;
  80         tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
  81         if (!tagp)
  82                 return FDT_END; /* premature end */
  83         tag = fdt32_to_cpu(*tagp);
  84         offset += FDT_TAGSIZE;
  85
  86         *nextoffset = -FDT_ERR_BADSTRUCTURE;
  87         switch (tag) {
  88         case FDT_BEGIN_NODE:
  89                 /* skip name */
  90                 do {
  91                         p = fdt_offset_ptr(fdt, offset++, 1);
  92                 } while (p && (*p != '\0'));
  93                 if (!p)
  94                         return FDT_END; /* premature end */
  95                 break;
  96
  97         case FDT_PROP:
  98                 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
  99                 if (!lenp)
 100                         return FDT_END; /* premature end */
 101                 /* skip-name offset, length and value */
 102                 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
 103                         + fdt32_to_cpu(*lenp);
 104                 break;
 105
 106         case FDT_END:
 107         case FDT_END_NODE:
 108         case FDT_NOP:
 109                 break;
 110
 111         default:
 112                 return FDT_END;
 113         }
 114
 115         if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
 116                 return FDT_END; /* premature end */
 117
 118         *nextoffset = FDT_TAGALIGN(offset);
 119         return tag;
 120 }
 121
 122 int _fdt_check_node_offset(const void *fdt, int offset)
 123 {
 124         if ((offset < 0) || (offset % FDT_TAGSIZE)
 125             || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
 126                 return -FDT_ERR_BADOFFSET;
 127
 128         return offset;
 129 }
 130
 131 int _fdt_check_prop_offset(const void *fdt, int offset)
 132 {
 133         if ((offset < 0) || (offset % FDT_TAGSIZE)
 134             || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
 135                 return -FDT_ERR_BADOFFSET;
 136
 137         return offset;
 138 }
 139
 140 int fdt_next_node(const void *fdt, int offset, int *depth)
 141 {
 142         int nextoffset = 0;
 143         uint32_t tag;
 144
 145         if (offset >= 0)
 146                 if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
 147                         return nextoffset;
 148
 149         do {
 150                 offset = nextoffset;
 151                 tag = fdt_next_tag(fdt, offset, &nextoffset);
 152
 153                 switch (tag) {
 154                 case FDT_PROP:
 155                 case FDT_NOP:
 156                         break;
 157
 158                 case FDT_BEGIN_NODE:
 159                         if (depth)
 160                                 (*depth)++;
 161                         break;
 162
 163                 case FDT_END_NODE:
 164                         if (depth && ((--(*depth)) < 0))
 165                                 return nextoffset;
 166                         break;
 167
 168                 case FDT_END:
 169                         if ((nextoffset >= 0)
 170                             || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
 171                                 return -FDT_ERR_NOTFOUND;
 172                         else
 173                                 return nextoffset;
 174                 }
 175         } while (tag != FDT_BEGIN_NODE);
 176
 177         return offset;
 178 }
 179
 180 const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
 181 {
 182         int len = strlen(s) + 1;
 183         const char *last = strtab + tabsize - len;
 184         const char *p;
 185
 186         for (p = strtab; p <= last; p++)
 187                 if (memcmp(p, s, len) == 0)
 188                         return p;
 189         return NULL;
 190 }
 191
 192 int fdt_move(const void *fdt, void *buf, int bufsize)
 193 {
 194         FDT_CHECK_HEADER(fdt);
 195
 196         if (fdt_totalsize(fdt) > bufsize)
 197                 return -FDT_ERR_NOSPACE;
 198
 199         memmove(buf, fdt, fdt_totalsize(fdt));
 200         return 0;
 201 }