elf_mem_map 14 KB

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  1. #!/usr/bin/env python3
  2. import argparse
  3. import elftools.elf.elffile
  4. import elftools.dwarf.descriptions
  5. from collections import namedtuple
  6. from struct import unpack
  7. SRAM_OFFSET = 0x800000
  8. EEPROM_OFFSET = 0x810000
  9. FILL_BYTE = b'\0'
  10. Entry = namedtuple('Entry', ['name', 'loc', 'size', 'declpos'])
  11. Member = namedtuple('Member', ['name', 'off', 'size'])
  12. def array_inc(loc, dim, idx=0):
  13. if idx == len(dim):
  14. return True
  15. loc[idx] += 1
  16. if loc[idx] == dim[idx]:
  17. loc[idx] = 0
  18. return array_inc(loc, dim, idx+1)
  19. return False
  20. def get_type_size(type_DIE):
  21. while True:
  22. if 'DW_AT_byte_size' in type_DIE.attributes:
  23. return type_DIE, type_DIE.attributes.get('DW_AT_byte_size').value
  24. if 'DW_AT_type' not in type_DIE.attributes:
  25. return None
  26. type_DIE = type_DIE.get_DIE_from_attribute('DW_AT_type')
  27. def get_type_arrsize(type_DIE):
  28. size = get_type_size(type_DIE)
  29. if size is None:
  30. return None
  31. byte_size = size[1]
  32. if size[0].tag != 'DW_TAG_pointer_type':
  33. array_DIE = get_type_def(type_DIE, 'DW_TAG_array_type')
  34. if array_DIE is not None:
  35. for range_DIE in array_DIE.iter_children():
  36. if range_DIE.tag == 'DW_TAG_subrange_type' and \
  37. 'DW_AT_upper_bound' in range_DIE.attributes:
  38. dim = range_DIE.attributes['DW_AT_upper_bound'].value + 1
  39. byte_size *= dim
  40. return byte_size
  41. def get_type_def(type_DIE, type_tag):
  42. while True:
  43. if type_DIE.tag == type_tag:
  44. return type_DIE
  45. if 'DW_AT_type' not in type_DIE.attributes:
  46. return None
  47. type_DIE = type_DIE.get_DIE_from_attribute('DW_AT_type')
  48. def get_FORM_block1(attr):
  49. if attr.form != 'DW_FORM_block1':
  50. return None
  51. if attr.value[0] == 3: # OP_addr
  52. return int.from_bytes(attr.value[1:], 'little')
  53. if attr.value[0] == 35: # OP_plus_uconst (ULEB128)
  54. v = 0
  55. s = 0
  56. for b in attr.value[1:]:
  57. v |= (b & 0x7f) << s
  58. if b & 0x80 == 0:
  59. break
  60. s += 7
  61. return v
  62. return None
  63. def get_array_dims(DIE):
  64. array_DIE = get_type_def(DIE, 'DW_TAG_array_type')
  65. if array_DIE is None:
  66. return []
  67. array_dim = []
  68. for range_DIE in array_DIE.iter_children():
  69. if range_DIE.tag == 'DW_TAG_subrange_type' and \
  70. 'DW_AT_upper_bound' in range_DIE.attributes:
  71. array_dim.append(range_DIE.attributes['DW_AT_upper_bound'].value + 1)
  72. return array_dim
  73. def get_struct_members(DIE, entry, expand_structs, struct_gaps):
  74. struct_DIE = get_type_def(DIE, 'DW_TAG_structure_type')
  75. if struct_DIE is None:
  76. return []
  77. members = []
  78. for member_DIE in struct_DIE.iter_children():
  79. if member_DIE.tag == 'DW_TAG_member' and 'DW_AT_name' in member_DIE.attributes:
  80. m_name = member_DIE.attributes['DW_AT_name'].value.decode('ascii')
  81. m_off = get_FORM_block1(member_DIE.attributes['DW_AT_data_member_location'])
  82. m_byte_size = get_type_size(member_DIE)[1]
  83. # still expand member arrays
  84. m_array_dim = get_array_dims(member_DIE)
  85. if m_byte_size == 1 and len(m_array_dim) > 1:
  86. # likely string, remove one dimension
  87. m_byte_size *= m_array_dim.pop()
  88. if len(m_array_dim) == 0 or (len(m_array_dim) == 1 and m_array_dim[0] == 1):
  89. # plain entry
  90. members.append(Member(m_name, m_off, m_byte_size))
  91. elif len(m_array_dim) == 1 and m_byte_size == 1:
  92. # likely string, avoid expansion
  93. members.append(Member(m_name + '[]', m_off, m_array_dim[0]))
  94. else:
  95. # expand array entries
  96. m_array_pos = m_off
  97. m_array_loc = [0] * len(m_array_dim)
  98. while True:
  99. # location index
  100. sfx = ''
  101. for d in range(len(m_array_dim)):
  102. sfx += '[{}]'.format(str(m_array_loc[d]).rjust(len(str(m_array_dim[d]-1)), '0'))
  103. members.append(Member(m_name + sfx, m_array_pos, m_byte_size))
  104. # advance
  105. if array_inc(m_array_loc, m_array_dim):
  106. break
  107. m_array_pos += m_byte_size
  108. if struct_gaps and len(members):
  109. # fill gaps in the middle
  110. members = list(sorted(members, key=lambda x: x.off))
  111. last_end = 0
  112. for n in range(len(members)):
  113. member = members[n]
  114. if member.off > last_end:
  115. members.append(Member('*UNKNOWN*', last_end, member.off - last_end))
  116. last_end = member.off + member.size
  117. if struct_gaps and len(members):
  118. # fill gap at the end
  119. members = list(sorted(members, key=lambda x: x.off))
  120. last = members[-1]
  121. last_end = last.off + last.size
  122. if entry.size > last_end:
  123. members.append(Member('*UNKNOWN*', last_end, entry.size - last_end))
  124. return members
  125. def get_elf_globals(path, expand_structs, struct_gaps=True):
  126. fd = open(path, "rb")
  127. if fd is None:
  128. return
  129. elffile = elftools.elf.elffile.ELFFile(fd)
  130. if elffile is None or not elffile.has_dwarf_info():
  131. return
  132. # probably not needed, since we're decoding expressions manually
  133. elftools.dwarf.descriptions.set_global_machine_arch(elffile.get_machine_arch())
  134. dwarfinfo = elffile.get_dwarf_info()
  135. grefs = []
  136. for CU in dwarfinfo.iter_CUs():
  137. file_entries = dwarfinfo.line_program_for_CU(CU).header["file_entry"]
  138. for DIE in CU.iter_DIEs():
  139. # handle only variable types
  140. if DIE.tag != 'DW_TAG_variable':
  141. continue
  142. if 'DW_AT_location' not in DIE.attributes:
  143. continue
  144. if 'DW_AT_name' not in DIE.attributes and \
  145. 'DW_AT_abstract_origin' not in DIE.attributes:
  146. continue
  147. # handle locations encoded directly as DW_OP_addr (leaf globals)
  148. loc = get_FORM_block1(DIE.attributes['DW_AT_location'])
  149. if loc is None or loc < SRAM_OFFSET or loc >= EEPROM_OFFSET:
  150. continue
  151. loc -= SRAM_OFFSET
  152. # variable name/type
  153. if 'DW_AT_name' not in DIE.attributes and \
  154. 'DW_AT_abstract_origin' in DIE.attributes:
  155. DIE = DIE.get_DIE_from_attribute('DW_AT_abstract_origin')
  156. if 'DW_AT_location' in DIE.attributes:
  157. # duplicate reference (handled directly), skip
  158. continue
  159. if 'DW_AT_name' not in DIE.attributes:
  160. continue
  161. if 'DW_AT_type' not in DIE.attributes:
  162. continue
  163. name = DIE.attributes['DW_AT_name'].value.decode('ascii')
  164. # get final storage size
  165. size = get_type_size(DIE)
  166. if size is None:
  167. continue
  168. byte_size = size[1]
  169. # location of main definition
  170. declpos = ''
  171. if 'DW_AT_decl_file' in DIE.attributes and \
  172. 'DW_AT_decl_line' in DIE.attributes:
  173. line = DIE.attributes['DW_AT_decl_line'].value
  174. fname = DIE.attributes['DW_AT_decl_file'].value
  175. if fname and fname - 1 < len(file_entries):
  176. fname = file_entries[fname-1].name.decode('ascii')
  177. declpos = '{}:{}'.format(fname, line)
  178. # fetch array dimensions (if known)
  179. array_dim = get_array_dims(DIE)
  180. # fetch structure members (one level only)
  181. entry = Entry(name, loc, byte_size, declpos)
  182. if not expand_structs or size[0].tag == 'DW_TAG_pointer_type':
  183. members = []
  184. else:
  185. members = get_struct_members(DIE, entry, expand_structs, struct_gaps)
  186. def expand_members(entry, members):
  187. if len(members) == 0:
  188. grefs.append(entry)
  189. else:
  190. for member in members:
  191. grefs.append(Entry(entry.name + '.' + member.name,
  192. entry.loc + member.off, member.size,
  193. entry.declpos))
  194. if byte_size == 1 and len(array_dim) > 1:
  195. # likely string, remove one dimension
  196. byte_size *= array_dim.pop()
  197. if len(array_dim) == 0 or (len(array_dim) == 1 and array_dim[0] == 1):
  198. # plain entry
  199. expand_members(entry, members)
  200. elif len(array_dim) == 1 and byte_size == 1:
  201. # likely string, avoid expansion
  202. grefs.append(Entry(entry.name + '[]', entry.loc,
  203. array_dim[0], entry.declpos))
  204. else:
  205. # expand array entries
  206. array_pos = loc
  207. array_loc = [0] * len(array_dim)
  208. while True:
  209. # location index
  210. sfx = ''
  211. for d in range(len(array_dim)):
  212. sfx += '[{}]'.format(str(array_loc[d]).rjust(len(str(array_dim[d]-1)), '0'))
  213. expand_members(Entry(entry.name + sfx, array_pos,
  214. byte_size, entry.declpos), members)
  215. # advance
  216. if array_inc(array_loc, array_dim):
  217. break
  218. array_pos += byte_size
  219. return grefs
  220. def decode_dump(path):
  221. fd = open(path, 'r')
  222. if fd is None:
  223. return None
  224. buf_addr = None # starting address
  225. buf_data = None # data
  226. for line in fd:
  227. tokens = line.split(maxsplit=1)
  228. if len(tokens) == 0 or tokens[0] == 'ok':
  229. break
  230. elif len(tokens) < 2 or tokens[0] == 'D2':
  231. continue
  232. addr = int.from_bytes(bytes.fromhex(tokens[0]), 'big')
  233. data = bytes.fromhex(tokens[1])
  234. if buf_addr is None:
  235. buf_addr = addr
  236. buf_data = data
  237. else:
  238. # grow buffer as needed
  239. if addr < buf_addr:
  240. buf_data = FILL_BYTE * (buf_addr - addr)
  241. buf_addr = addr
  242. addr_end = addr + len(data)
  243. buf_end = buf_addr + len(buf_data)
  244. if addr_end > buf_end:
  245. buf_data += FILL_BYTE * (addr_end - buf_end)
  246. # replace new part
  247. rep_start = addr - buf_addr
  248. rep_end = rep_start + len(data)
  249. buf_data = buf_data[:rep_start] + data + buf_data[rep_end:]
  250. return (buf_addr, buf_data)
  251. def annotate_refs(grefs, addr, data, width, gaps=True, overlaps=True):
  252. last_end = None
  253. for entry in grefs:
  254. if entry.loc < addr:
  255. continue
  256. if entry.loc + entry.size > addr + len(data):
  257. continue
  258. pos = entry.loc-addr
  259. end_pos = pos + entry.size
  260. buf = data[pos:end_pos]
  261. buf_repr = ''
  262. if len(buf) in [1, 2, 4]:
  263. # attempt to decode as integers
  264. buf_repr += ' I:' + str(int.from_bytes(buf, 'little')).rjust(10)
  265. if len(buf) in [4, 8]:
  266. # attempt to decode as floats
  267. typ = 'f' if len(buf) == 4 else 'd'
  268. buf_repr += ' F:' + '{:10.3f}'.format(unpack(typ, buf)[0])
  269. if last_end is not None:
  270. if gaps and last_end < pos:
  271. # decode gaps
  272. gap_size = pos - last_end
  273. gap_buf = data[last_end:pos]
  274. print('{:04x} {} {:4} R:{}'.format(addr+last_end, "*UNKNOWN*".ljust(width),
  275. gap_size, gap_buf.hex()))
  276. if overlaps and last_end > pos + 1:
  277. gap_size = pos - last_end
  278. print('{:04x} {} {:4}'.format(addr+last_end, "*OVERLAP*".ljust(width), gap_size))
  279. print('{:04x} {} {:4}{} R:{}'.format(entry.loc, entry.name.ljust(width),
  280. entry.size, buf_repr, buf.hex()))
  281. last_end = end_pos
  282. def print_map(grefs):
  283. print('OFFSET\tSIZE\tNAME\tDECLPOS')
  284. for entry in grefs:
  285. print('{:x}\t{}\t{}\t{}'.format(entry.loc, entry.size, entry.name, entry.declpos))
  286. def main():
  287. ap = argparse.ArgumentParser(description="""
  288. Generate a symbol table map starting directly from an ELF
  289. firmware with DWARF2 debugging information.
  290. When used along with a memory dump obtained from the D2 g-code,
  291. show the value of each symbol which is within the address range.
  292. """)
  293. ap.add_argument('elf', help='ELF file containing DWARF2 debugging information')
  294. ap.add_argument('--no-gaps', action='store_true',
  295. help='do not dump memory inbetween known symbols')
  296. ap.add_argument('--no-expand-structs', action='store_true',
  297. help='do not decode structure data')
  298. ap.add_argument('--overlaps', action='store_true',
  299. help='annotate overlaps greater than 1 byte')
  300. ap.add_argument('--name-width', type=int, default=50,
  301. help='set name column width')
  302. g = ap.add_mutually_exclusive_group(required=True)
  303. g.add_argument('dump', nargs='?', help='RAM dump obtained from D2 g-code')
  304. g.add_argument('--map', action='store_true', help='dump global memory map')
  305. args = ap.parse_args()
  306. grefs = get_elf_globals(args.elf, expand_structs=not args.no_expand_structs)
  307. grefs = list(sorted(grefs, key=lambda x: x.loc))
  308. if args.dump is None:
  309. print_map(grefs)
  310. else:
  311. addr, data = decode_dump(args.dump)
  312. annotate_refs(grefs, addr, data,
  313. width=args.name_width,
  314. gaps=not args.no_gaps,
  315. overlaps=args.overlaps)
  316. if __name__ == '__main__':
  317. exit(main())