/scripts/dtc/libfdt/fdt.c

http://github.com/mirrors/linux · C · 316 lines · 243 code · 52 blank · 21 comment · 95 complexity · 48592d1dc50960af78f1f40a25281168 MD5 · raw file

  1. // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
  2. /*
  3. * libfdt - Flat Device Tree manipulation
  4. * Copyright (C) 2006 David Gibson, IBM Corporation.
  5. */
  6. #include "libfdt_env.h"
  7. #include <fdt.h>
  8. #include <libfdt.h>
  9. #include "libfdt_internal.h"
  10. /*
  11. * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
  12. * that the given buffer contains what appears to be a flattened
  13. * device tree with sane information in its header.
  14. */
  15. int32_t fdt_ro_probe_(const void *fdt)
  16. {
  17. uint32_t totalsize = fdt_totalsize(fdt);
  18. if (can_assume(VALID_DTB))
  19. return totalsize;
  20. if (fdt_magic(fdt) == FDT_MAGIC) {
  21. /* Complete tree */
  22. if (!can_assume(LATEST)) {
  23. if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  24. return -FDT_ERR_BADVERSION;
  25. if (fdt_last_comp_version(fdt) >
  26. FDT_LAST_SUPPORTED_VERSION)
  27. return -FDT_ERR_BADVERSION;
  28. }
  29. } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
  30. /* Unfinished sequential-write blob */
  31. if (!can_assume(VALID_INPUT) && fdt_size_dt_struct(fdt) == 0)
  32. return -FDT_ERR_BADSTATE;
  33. } else {
  34. return -FDT_ERR_BADMAGIC;
  35. }
  36. if (totalsize < INT32_MAX)
  37. return totalsize;
  38. else
  39. return -FDT_ERR_TRUNCATED;
  40. }
  41. static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
  42. {
  43. return (off >= hdrsize) && (off <= totalsize);
  44. }
  45. static int check_block_(uint32_t hdrsize, uint32_t totalsize,
  46. uint32_t base, uint32_t size)
  47. {
  48. if (!check_off_(hdrsize, totalsize, base))
  49. return 0; /* block start out of bounds */
  50. if ((base + size) < base)
  51. return 0; /* overflow */
  52. if (!check_off_(hdrsize, totalsize, base + size))
  53. return 0; /* block end out of bounds */
  54. return 1;
  55. }
  56. size_t fdt_header_size_(uint32_t version)
  57. {
  58. if (version <= 1)
  59. return FDT_V1_SIZE;
  60. else if (version <= 2)
  61. return FDT_V2_SIZE;
  62. else if (version <= 3)
  63. return FDT_V3_SIZE;
  64. else if (version <= 16)
  65. return FDT_V16_SIZE;
  66. else
  67. return FDT_V17_SIZE;
  68. }
  69. size_t fdt_header_size(const void *fdt)
  70. {
  71. return can_assume(LATEST) ? FDT_V17_SIZE :
  72. fdt_header_size_(fdt_version(fdt));
  73. }
  74. int fdt_check_header(const void *fdt)
  75. {
  76. size_t hdrsize;
  77. if (fdt_magic(fdt) != FDT_MAGIC)
  78. return -FDT_ERR_BADMAGIC;
  79. if (!can_assume(LATEST)) {
  80. if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  81. || (fdt_last_comp_version(fdt) >
  82. FDT_LAST_SUPPORTED_VERSION))
  83. return -FDT_ERR_BADVERSION;
  84. if (fdt_version(fdt) < fdt_last_comp_version(fdt))
  85. return -FDT_ERR_BADVERSION;
  86. }
  87. hdrsize = fdt_header_size(fdt);
  88. if (!can_assume(VALID_DTB)) {
  89. if ((fdt_totalsize(fdt) < hdrsize)
  90. || (fdt_totalsize(fdt) > INT_MAX))
  91. return -FDT_ERR_TRUNCATED;
  92. /* Bounds check memrsv block */
  93. if (!check_off_(hdrsize, fdt_totalsize(fdt),
  94. fdt_off_mem_rsvmap(fdt)))
  95. return -FDT_ERR_TRUNCATED;
  96. }
  97. if (!can_assume(VALID_DTB)) {
  98. /* Bounds check structure block */
  99. if (!can_assume(LATEST) && fdt_version(fdt) < 17) {
  100. if (!check_off_(hdrsize, fdt_totalsize(fdt),
  101. fdt_off_dt_struct(fdt)))
  102. return -FDT_ERR_TRUNCATED;
  103. } else {
  104. if (!check_block_(hdrsize, fdt_totalsize(fdt),
  105. fdt_off_dt_struct(fdt),
  106. fdt_size_dt_struct(fdt)))
  107. return -FDT_ERR_TRUNCATED;
  108. }
  109. /* Bounds check strings block */
  110. if (!check_block_(hdrsize, fdt_totalsize(fdt),
  111. fdt_off_dt_strings(fdt),
  112. fdt_size_dt_strings(fdt)))
  113. return -FDT_ERR_TRUNCATED;
  114. }
  115. return 0;
  116. }
  117. const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
  118. {
  119. unsigned absoffset = offset + fdt_off_dt_struct(fdt);
  120. if (!can_assume(VALID_INPUT))
  121. if ((absoffset < offset)
  122. || ((absoffset + len) < absoffset)
  123. || (absoffset + len) > fdt_totalsize(fdt))
  124. return NULL;
  125. if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
  126. if (((offset + len) < offset)
  127. || ((offset + len) > fdt_size_dt_struct(fdt)))
  128. return NULL;
  129. return fdt_offset_ptr_(fdt, offset);
  130. }
  131. uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
  132. {
  133. const fdt32_t *tagp, *lenp;
  134. uint32_t tag;
  135. int offset = startoffset;
  136. const char *p;
  137. *nextoffset = -FDT_ERR_TRUNCATED;
  138. tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
  139. if (!can_assume(VALID_DTB) && !tagp)
  140. return FDT_END; /* premature end */
  141. tag = fdt32_to_cpu(*tagp);
  142. offset += FDT_TAGSIZE;
  143. *nextoffset = -FDT_ERR_BADSTRUCTURE;
  144. switch (tag) {
  145. case FDT_BEGIN_NODE:
  146. /* skip name */
  147. do {
  148. p = fdt_offset_ptr(fdt, offset++, 1);
  149. } while (p && (*p != '\0'));
  150. if (!can_assume(VALID_DTB) && !p)
  151. return FDT_END; /* premature end */
  152. break;
  153. case FDT_PROP:
  154. lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
  155. if (!can_assume(VALID_DTB) && !lenp)
  156. return FDT_END; /* premature end */
  157. /* skip-name offset, length and value */
  158. offset += sizeof(struct fdt_property) - FDT_TAGSIZE
  159. + fdt32_to_cpu(*lenp);
  160. if (!can_assume(LATEST) &&
  161. fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
  162. ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
  163. offset += 4;
  164. break;
  165. case FDT_END:
  166. case FDT_END_NODE:
  167. case FDT_NOP:
  168. break;
  169. default:
  170. return FDT_END;
  171. }
  172. if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
  173. return FDT_END; /* premature end */
  174. *nextoffset = FDT_TAGALIGN(offset);
  175. return tag;
  176. }
  177. int fdt_check_node_offset_(const void *fdt, int offset)
  178. {
  179. if (can_assume(VALID_INPUT))
  180. return offset;
  181. if ((offset < 0) || (offset % FDT_TAGSIZE)
  182. || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
  183. return -FDT_ERR_BADOFFSET;
  184. return offset;
  185. }
  186. int fdt_check_prop_offset_(const void *fdt, int offset)
  187. {
  188. if ((offset < 0) || (offset % FDT_TAGSIZE)
  189. || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
  190. return -FDT_ERR_BADOFFSET;
  191. return offset;
  192. }
  193. int fdt_next_node(const void *fdt, int offset, int *depth)
  194. {
  195. int nextoffset = 0;
  196. uint32_t tag;
  197. if (offset >= 0)
  198. if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
  199. return nextoffset;
  200. do {
  201. offset = nextoffset;
  202. tag = fdt_next_tag(fdt, offset, &nextoffset);
  203. switch (tag) {
  204. case FDT_PROP:
  205. case FDT_NOP:
  206. break;
  207. case FDT_BEGIN_NODE:
  208. if (depth)
  209. (*depth)++;
  210. break;
  211. case FDT_END_NODE:
  212. if (depth && ((--(*depth)) < 0))
  213. return nextoffset;
  214. break;
  215. case FDT_END:
  216. if ((nextoffset >= 0)
  217. || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
  218. return -FDT_ERR_NOTFOUND;
  219. else
  220. return nextoffset;
  221. }
  222. } while (tag != FDT_BEGIN_NODE);
  223. return offset;
  224. }
  225. int fdt_first_subnode(const void *fdt, int offset)
  226. {
  227. int depth = 0;
  228. offset = fdt_next_node(fdt, offset, &depth);
  229. if (offset < 0 || depth != 1)
  230. return -FDT_ERR_NOTFOUND;
  231. return offset;
  232. }
  233. int fdt_next_subnode(const void *fdt, int offset)
  234. {
  235. int depth = 1;
  236. /*
  237. * With respect to the parent, the depth of the next subnode will be
  238. * the same as the last.
  239. */
  240. do {
  241. offset = fdt_next_node(fdt, offset, &depth);
  242. if (offset < 0 || depth < 1)
  243. return -FDT_ERR_NOTFOUND;
  244. } while (depth > 1);
  245. return offset;
  246. }
  247. const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
  248. {
  249. int len = strlen(s) + 1;
  250. const char *last = strtab + tabsize - len;
  251. const char *p;
  252. for (p = strtab; p <= last; p++)
  253. if (memcmp(p, s, len) == 0)
  254. return p;
  255. return NULL;
  256. }
  257. int fdt_move(const void *fdt, void *buf, int bufsize)
  258. {
  259. FDT_RO_PROBE(fdt);
  260. if (fdt_totalsize(fdt) > bufsize)
  261. return -FDT_ERR_NOSPACE;
  262. memmove(buf, fdt, fdt_totalsize(fdt));
  263. return 0;
  264. }