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elfutils.py
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elfutils.py
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#-*-encoding=utf-8-*-
import os
import mmap
import io
import pdb
import dwarf
import struct
from cStringIO import StringIO
"""
去掉baseutils
参考golang, elfutils重新设计接口
提高struct的使用效率
解释清楚ELF标准里每个的用途
完全支持elf标准里的各种计算
支持读取与生成
支持dwarf调试信息的读取与生成
"""
elf = None
#options
ELF_HEADER = 1 << 2
ELF_SYMBOL = 1 << 3
ELF_DYNAMIC = 1 << 4
ELF_RELA = 1 << 5
ELF_PSECTION = 1 << 6
ELF_VERNEED = 1 << 7
DWARF_INFO = 1 << 10
#types
ELF64 = 8
ELF32 = 4
ELF16 = 2
ELF8 = 1
def load_struct(buffer, d, fmt):
fmt_str = "".join([x[1] for x in fmt])
size = struct.calcsize(fmt_str)
raw = buffer.read(size)
if len(raw) != size:
raise Exception("Truncated Stream")
unpacked_raw = struct.unpack(fmt_str, raw)
for i, m in enumerate(fmt):
d[m[0]] = unpacked_raw[i]
elf32_hdr_format = (
("e_type", "H"),
("e_machine", "H"),
("e_version", "I"),
("e_entry", "I"),
("e_phoff", "I"),
("e_shoff", "I"),
("e_flags", "I"),
("e_ehsize", "H"),
("e_phentsize", "H"),
("e_phnum", "H"),
("e_shentsize", "H"),
("e_shnum", "H"),
("e_shstrndx", "H")
)
elf64_hdr_format = (
("e_type", "H"),
("e_machine", "H"),
("e_version", "I"),
("e_entry", "Q"),
("e_phoff", "Q"),
("e_shoff", "Q"),
("e_flags", "I"),
("e_ehsize", "H"),
("e_phentsize", "H"),
("e_phnum", "H"),
("e_shentsize", "H"),
("e_shnum", "H"),
("e_shstrndx", "H")
)
elf32_shdr_format = (
("sh_name", "I"),
("sh_type", "I"),
("sh_flags", "I"),
("sh_addr", "I"),
("sh_offset", "I"),
("sh_size", "I"),
("sh_link", "I"),
("sh_info", "I"),
("sh_addralign", "I"),
("sh_entsize", "I")
)
elf64_shdr_format = (
("sh_name", "I"),
("sh_type", "I"),
("sh_flags", "Q"),
("sh_addr", "Q"),
("sh_offset", "Q"),
("sh_size", "Q"),
("sh_link", "I"),
("sh_info", "I"),
("sh_addralign", "Q"),
("sh_entsize", "Q")
)
elf32_phdr_format = (
("p_type", "I"),
("p_offset", "I"),
("p_vaddr", "I"),
("p_paddr", "I"),
("p_filesz", "I"),
("p_memsz", "I"),
("p_flags", "I"),
("p_align", "I")
)
elf64_phdr_format = (
("p_type", "I"),
("p_flags", "I"),
("p_offset", "Q"),
("p_vaddr", "Q"),
("p_paddr", "Q"),
("p_filesz", "Q"),
("p_memsz", "Q"),
("p_align", "Q")
)
elf32_sym_format = (
("st_name", "I"),
("st_value", "I"),
("st_size", "I"),
("st_info", "B"),
("st_other", "B"),
("st_shndx", "H")
)
elf64_sym_format = (
("st_name", "I"),
("st_info", "B"),
("st_other", "B"),
("st_shndx", "H"),
("st_value", "Q"),
("st_size", "Q")
)
verdef_format = (
("vd_version", "H"),
("vd_flags", "H"),
("vd_ndx", "H"),
("vd_cnt", "H"),
("vd_hash", "I"),
("vd_aux", "I"),
("vd_next", "I")
)
verdaux_format = (
("vda_name", "I"),
("vda_next", "I")
)
verneed_format = (
("vn_version", "H"),
("vn_cnt", "H"),
("vn_file", "I"),
("vn_aux", "I"),
("vn_next", "I")
)
vernaux_format = (
("vna_hash", "I"),
("vna_flags", "H"),
("vna_other", "H"),
("vna_name", "I"),
("vna_next", "I")
)
elf32_rel_format = (
("r_offset", "I"),
("r_info", "I")
)
elf64_rel_format = (
("r_offset", "Q"),
("r_info", "Q")
)
elf32_rela_format = (
("r_offset", "I"),
("r_info", "I"),
("r_addend", "I")
)
elf64_rela_format = (
("r_offset", "Q"),
("r_info", "Q"),
("r_addend", "Q")
)
HIGHBITMASK = 0b1111111
LOWBITSHIFT = 7
ELFSIG = "\x7fELF"
EM_NONE = 0
EM_386 = 3
EM_X86_64 = 62
elf_arch_type = {
0: "EM_NONE",
3: "EM_386",
62: "EM_X86_64"
}
ELFDATANONE = 0
ELFDATA2LSB = 1
ELFDATA2MSB = 2
elf_encoding = {
0: "ELFDATANONE",
1: "ELFDATA2LSB",
2: "ELFDATA2MSB"
}
ELFCLASSNONE = 0
ELFCLASS32 = 1
ELFCLASS64 = 2
elf_class_type = {
0: "ELFCLASSNONE",
1: "ELFCLASS32",
2: "ELFCLASS64"
}
ET_NONE = 0
ET_REL = 1
ET_EXEC = 2
ET_DYN = 3
ET_CORE = 4
elf_type = {
0: "ET_NONE",
1: "ET_REL",
2: "ET_EXEC",
3: "ET_DYN",
4: "ET_CORE"
}
SHT_NULL = 0
SHT_PROGBITS = 1
SHT_SYMTAB = 2
SHT_STRTAB = 3
SHT_RELA = 4
SHT_HASH = 5
SHT_DYNAMIC = 6
SHT_NOTE = 7
SHT_NOBITS = 8
SHT_REL = 9
SHT_SHLIB = 10
SHT_DYNSYM = 11
SHT_INIT_ARRAY = 14
SHT_FINI_ARRAY = 15
SHT_PREINIT_ARRAY = 16
SHT_GROUP = 17
SHT_SYMTAB_SHNDX = 18
SHT_LOOS = 0x60000000
SHT_GNU_INCREMENTAL_INPUTS = 0x6fff4700
SHT_GNU_ATTRIBUTES = 0x6ffffff5
SHT_GNU_HASH = 0x6ffffff6
SHT_GNU_LIBLIST = 0x6ffffff7
SHT_GNU_verdef = 0x6ffffffd
SHT_GNU_verneed = 0x6ffffffe
SHT_GNU_versym = 0x6fffffff
sh_type = {
0: "SHT_NULL",
1: "SHT_PROGBITS",
2: "SHT_SYMTAB",
3: "SHT_STRTAB",
4: "SHT_RELA",
5: "SHT_HASH",
6: "SHT_DYNAMIC",
7: "SHT_NOTE",
8: "SHT_NOBITS",
9: "SHT_REL",
10: "SHT_SHLIB",
11: "SHT_DYNSYM",
14: "SHT_INIT_ARRAY",
15: "SHT_FINI_ARRAY",
16: "SHT_PREINIT_ARRAY",
17: "SHT_GROUP",
18: "SHT_SYMTAB_SHNDX",
0x60000000: "SHT_LOOS",
0x6fff4700: "SHT_GNU_INCREMENTAL_INPUTS",
0x6ffffff5: "SHT_GNU_ATTRIBUTES",
0x6ffffff6: "SHT_GNU_HASH",
0x6ffffff7: "SHT_GNU_LIBLIST",
0x6ffffffd: "SHT_GNU_verdef",
0x6ffffffe: "SHT_GNU_verneed",
0x6fffffff: "SHT_GNU_versym"
}
SHF_NONE = 0
SHF_ALLOC = 1 << 0
SHF_EXECINSTR = 1<< 2
SHF_MERGE = 1 << 4
SHF_STRINGS = 1 << 5
SHF_INFO_LINK = 1 << 6
SHF_LINK_ORDER = 1 << 7
SHF_OS_NONCONFORMING = 1 << 8
SHF_GROUP = 1 << 9
SHF_TLS = 1 << 10
SHF_MASKOS = 0x0ff00000
SHF_MASKPROC = 0xf0000000
SHF_EXCLUDE = 0x80000000
sh_flags = {
0: "SHF_NONE",
1 << 0: "SHF_WRITE",
1 << 1: "SHF_ALLOC",
1 << 2: "SHF_EXECINSTR",
1 << 4: "SHF_MERGE",
1 << 5: "SHF_STRINGS",
1 << 6: "SHF_INFO_LINK",
1 << 7: "SHF_LINK_ORDER",
1 << 8: "SHF_OS_NONCONFORMING",
1 << 9: "SHF_GROUP",
1 << 10: "SHF_TLS",
0x0ff00000: "SHF_MASKOS",
0xf0000000: "SHF_MASKPROC",
0x80000000: "SHF_EXCLUDE"
}
def decide_shflags(flag):
t = []
for key in sh_flags:
if flag & key:
t.append(sh_flags[key])
return "+".join(t)
PT_NULL = 0
PT_LOAD = 1
PT_DYNMAIC = 2
PT_INTERP = 3
PT_NOTE = 4
PT_SHLIB = 5
PT_PHDR = 6
PT_TLS = 7
PT_LOOS = 0x60000000
PT_HIOS = 0x6fffffff
PT_LOPROC = 0x70000000
PT_HIPROC = 0x7fffffff
PT_GNU_EH_FRAME = 0x6474e550
PT_GNU_STACK = 0x6474e551
PT_GNU_RELRO = 0x6474e552
ph_type = {
0: "PT_NULL",
1: "PT_LOAD",
2: "PT_DYNMAIC",
3: "PT_INTERP",
4: "PT_NOTE",
5: "PT_SHLIB",
6: "PT_PHDR",
7: "PT_TLS",
0x60000000: "PT_LOOS",
0x6fffffff: "PT_HIOS",
0x70000000: "PT_LOPROC",
0x7fffffff: "PT_HIPROC",
0x6474e550: "PT_GNU_EH_FRAME",
0x6474e551: "PT_GNU_STACK",
0x6474e552: "PT_GNU_RELRO"
}
ph_flags = {
0: "NULL",
1: "PF_X",
2: "PF_W",
3: "PF_W + PF_X",
4: "PF_R",
5: "PF_R + PF_X",
6: "PF_R + PF_W",
7: "PF_R + PF_W + PF_X"
}
DT_NEEDED = 1
DT_SONAME = 14
DT_RPATH = 15
DT_FLAGS = 30
DT_FLAGS_1 = 0x6ffffffb
dynamic_type = {
0: "DT_NULL",
1: "DT_NEEDED",
2: "DT_PLTRELSZ",
3: "DT_PLTGOT",
4: "DT_HASH",
5: "DT_STRTAB",
6: "DT_SYMTAB",
7: "DT_RELA",
8: "DT_RELASZ",
9: "DT_RELAENT",
10: "DT_STRSZ",
11: "DT_SYMENT",
12: "DT_INIT",
13: "DT_FINI",
14: "DT_SONAME",
15: "DT_RPATH",
16: "DT_SYMBOLIC",
17: "DT_REL",
18: "DT_RELSZ",
19: "DT_RELENT",
20: "DT_PLTREL",
21: "DT_DEBUG",
22: "DT_TEXTREL",
23: "DT_JMPREL",
24: "DT_BIND_NOW",
25: "DT_INIT_ARRAY",
26: "DT_FINI_ARRAY",
27: "DT_INIT_ARRAYSZ",
28: "DT_FINI_ARRAYSZ",
29: "DT_RUNPATH",
30: "DT_FLAGS",
31: "DT_ENCODING",
32: "DT_PREINIT_ARRAY",
33: "DT_PREINIT_ARRAYSZ",
0x6000000d: "DT_LOOS",
0x6ffff000: "DT_HIOS",
0x70000000: "DT_LOPROC",
0x7fffffff: "DT_HIPROC",
0x6ffffd00: "DT_VALRNGLO",
0x6ffffdf5: "DT_GNU_PRELINKED",
0x6ffffdf6: "DT_GNU_CONFLICTSZ",
0x6ffffdf7: "DT_GNU_LIBLISTSZ",
0x6ffffdf8: "DT_CHECKSUM",
0x6ffffdf9: "DT_PLTPADSZ",
0x6ffffdfa: "DT_MOVEENT",
0x6ffffdfb: "DT_MOVESZ",
0x6ffffdfc: "DT_FEATURE",
0x6ffffdfd: "DT_POSFLAG_1",
0x6ffffdfe: "DT_SYMINSZ",
0x6ffffdff: "DT_SYMINENT",
0x6ffffe00: "DT_ADDRRNGLO",
0x6ffffef5: "DT_GNU_HASH",
0x6ffffef6: "DT_TLSDESC_PLT",
0x6ffffef7: "DT_TLSDESC_GOT",
0x6ffffef8: "DT_GNU_CONFLICT",
0x6ffffef9: "DT_GNU_LIBLIST",
0x6ffffefa: "DT_CONFIG",
0x6ffffefb: "DT_DEPAUDIT",
0x6ffffefc: "DT_AUDIT",
0x6ffffefd: "DT_PLTPAD",
0x6ffffefe: "DT_MOVETAB",
0x6ffffeff: "DT_SYMINFO",
0x6ffffff9: "DT_RELACOUNT",
0x6ffffffa: "DT_RELCOUNT",
0x6ffffffb: "DT_FLAGS_1",
0x6ffffffc: "DT_VERDEF",
0x6ffffffd: "DT_VERDEFNUM",
0x6ffffffe: "DT_VERNEED",
0x6fffffff: "DT_VERNEEDNUM",
0x6ffffff0: "DT_VERSYM"
}
DT_FLAGS_type = {
1 << 0: "DF_ORIGIN",
1 << 1: "DF_SYMBOLIC",
1 << 2: "DF_TEXTREL",
1 << 3: "DF_BIND_NOW",
1 << 4: "DF_STATIC_TLS"
}
DT_FLAGS_1_type = {
0x1: "DT_1_NOW",
0x2: "DT_1_GLOBAL",
0x4: "DT_1_GROUP",
0x8: "DT_1_NODELETE",
0x10: "DT_1_LOADFLTR",
0x20: "DT_1_INITFIRST",
0x40: "DT_1_NOOPEN",
0x80: "DT_1_ORIGIN",
0x100: "DT_1_DIRECT",
0x200: "DT_1_TRANS",
0x400: "DT_1_INTERPOSE",
0x800: "DT_1_NODEFLIB",
0x1000: "DT_1_NODUMP",
0x2000: "DT_1_CONLFAT"
}
rel_type = {
0: "R_386_NONE",
1: "R_386_32",
2: "R_386_PC32",
3: "R_386_GOT32",
4: "R_386_PLT32",
5: "R_386_COPY",
6: "R_386_GLOB_DAT",
7: "R_386_JMP_SLOT",
8: "R_386_RELATIVE",
9: "R_386_GOTOFF",
10: "R_386_GOTPC"
}
sym_type = {
0: "STT_NOTYPE",
1: "STT_OBJECT",
2: "STT_FUNC",
3: "STT_SECTION",
4: "STT_FILE",
5: "STT_COMMON",
6: "STT_TLS",
8: "STT_RELC",
9: "STT_SRELC",
10: "STT_LOOS",
12: "STT_HIOS",
13: "STT_LOPROC",
15: "STT_HIPROC"
}
sym_bind_type = {
0: "STB_LOCAL",
1: "STB_GLOBAL",
2: "STB_WEAK",
10: "STB_UNIQUE"
}
sym_spec_index = {
0: "SHN_UNDEF",
0xff00: "SHN_LOPROC",
0xff1f: "SHN_HIPROC",
0xfff1: "SHN_ABS",
0xfff2: "SHN_COMMON",
0xffff: "HIRESERVE"
}
sym_vis_type = {
0: "STV_DEFAULT",
1: "STV_INTERNAL",
2: "STV_HIDDEN",
3: "STV_PROTECTED"
}
def print_mem_usage(position):
Mib = 1024
pagesize = 4
f = open("/proc/%d/statm" % os.getpid(), "r")
mems = f.read().split(" ")
print "in", position
print "VM: %dm PHYM: %dm" % (int(mems[0]) * pagesize / Mib,
int(mems[1]) * pagesize / Mib)
f.close()
def read_header(elf, buffer):
buffer.seek(0)
elf_header = elf['elf_header']
elf_header["file_ident"] = buffer.read(ELF32)
if elf_header["file_ident"] != ELFSIG:
raise ValueError("This is not a ELF object")
file_class = ord(buffer.read(ELF8))
if file_class == ELFCLASS32:
hdr_format = elf32_hdr_format
elif file_class == ELFCLASS64:
hdr_format = elf64_hdr_format
else:
raise ValueError("Unknown ELFCLASS: %d", file_class)
elf_header["file_class"] = file_class
elf_header["file_encoding"] = ord(buffer.read(ELF8))
elf_header["file_version"] = ord(buffer.read(ELF8))
#ignore 9 bytes
buffer.seek(9, io.SEEK_CUR)
load_struct(buffer, elf_header, hdr_format)
def read_section_header(elf, buffer):
elf_header = elf["elf_header"]
sections = elf["sections"]
e_shoff = elf_header["e_shoff"]
buffer.seek(e_shoff)
e_shnum = elf_header["e_shnum"]
if elf_header["file_class"] == ELFCLASS32:
shdr_format = elf32_shdr_format
elif elf_header["file_class"] == ELFCLASS64:
shdr_format = elf64_shdr_format
else:
raise ValueError("Unknown ELFCLASS: %d", file_class)
for num in range(e_shnum):
section = {}
load_struct(buffer, section, shdr_format)
sections.append(section)
def read_program_header(elf, buffer):
elf_header = elf["elf_header"]
programs = elf["programs"]
buffer.seek(elf_header["e_phoff"])
e_phnum = elf_header["e_phnum"]
if elf_header["file_class"] == ELFCLASS32:
phdr_format = elf32_phdr_format
elif elf_header["file_class"] == ELFCLASS64:
phdr_format = elf64_phdr_format
else:
raise ValueError("Unknown ELFCLASS: %d", file_class)
elf_type = elf_header["file_class"]
for num in range(e_phnum):
entry = {}
load_struct(buffer, entry, phdr_format)
#INTERP
if entry['p_type'] == PT_INTERP:
mark = buffer.tell()
buffer.seek(entry['p_offset'])
elf['interpreter'] = buffer.read(entry['p_filesz'])
buffer.seek(mark)
programs.append(entry)
def build_strtab(buffer, section):
buffer.seek(section["sh_offset"])
size = section["sh_size"]
raw = buffer.read(size)
strtab = {}
strend = "\x00"
i = 0
while i < size:
if raw[i] != strend:
i += 1
continue
j = i + 1
end = raw.find(strend, j)
if end == -1:
break
name = raw[j:end]
more = name.find(".", 1)
if more > 0:
strtab[j+more] = name[more:]
strtab[j] = name
i = end
return strtab
def read_strtab(elf, buffer):
elf_header = elf["elf_header"]
sections = elf["sections"]
strtab_sections = []
for section in sections:
if section["sh_type"] == SHT_STRTAB:
strtab_sections.append(section)
shstrtab_section = None
for section in strtab_sections:
buffer.seek(section["sh_offset"])
if ".text" in buffer.read(section["sh_size"]):
shstrtab_section = section
if not shstrtab_section:
print "error: where is .shstrtab?"
return
shstrtab = build_strtab(buffer, shstrtab_section)
for section in sections[1:]:
section["sh_name"] = shstrtab[section["sh_name"]]
for section in strtab_sections:
name = section["sh_name"]
strtab = build_strtab(buffer, section)
elf["strtabs"][name] = strtab
def read_symtab(elf, buffer):
sections = elf["sections"]
symtabs = elf["symtabs"]
elf_header= elf["elf_header"]
symtab_sections = []
for section in sections:
if section["sh_type"] == SHT_SYMTAB:
symtab_sections.append(section)
if section["sh_type"] == SHT_DYNSYM:
symtab_sections.append(section)
sym_read = buffer.read
if elf_header["file_class"] == ELFCLASS32:
sym_format = elf32_sym_format
elif elf_header["file_class"] == ELFCLASS64:
sym_format = elf64_sym_format
else:
raise ValueError("Unknown ELFCLASS: %d", file_class)
try:
strtab = elf["strtabs"][".strtab"]
strtab_keys = sorted(strtab.keys(), reverse=True)
except KeyError:
pass
try:
dynsym = elf["strtabs"][".dynstr"]
dynsym_keys = sorted(dynsym.keys(), reverse=True)
except KeyError:
pass
for section in symtab_sections:
buffer.seek(section["sh_offset"])
total = section["sh_size"] / section["sh_entsize"]
symtab = []
section_name = section["sh_name"]
for entry in range(total):
sym = {}
load_struct(buffer, sym, sym_format)
sym_name = sym["st_name"]
if not sym_name:
sym["st_name"] = "unknown"
elif section_name == ".symtab":
try:
sym["st_name"] = strtab[sym_name]
except KeyError as e:
#slow find
for i in strtab_keys:
if i < sym_name:
sym["st_name"] = strtab[i][sym_name-i:]
break
elif section_name == ".dynsym":
try:
sym["st_name"] = dynsym[sym_name]
except KeyError as e:
#slow find
for i in dynsym_keys:
if i < sym_name:
sym["st_name"] = dynsym[i][sym_name-i:]
break
sym["st_bind"] = sym["st_info"] >> 4
sym["st_type"] = sym["st_info"] & 0xf
symtab.append(sym)
symtabs[section["sh_name"]] = symtab
def read_rel(elf, buffer):
sections = elf["sections"]
rel_list = []
for section in sections:
if section["sh_type"] == SHT_REL:
rel_list.append(section)
elf_type = elf["elf_header"]["file_class"]
symtab = elf["symtabs"][".dynsym"]
elf["rel"] = {}
for rel in rel_list:
r1_list = []
buffer.seek(rel["sh_offset"])
if elf_type == ELFCLASS32:
for i in range(rel["sh_size"] / rel["sh_entsize"]):
entry = {}
load_struct(buffer, entry, elf32_rel_format)
r_info = entry["r_info"]
entry["r_symbol"] = r_info >> 8
entry["r_type"] = r_info & 0xff
r1_list.append(entry)
else:
for i in range(rel["sh_size"] / rel["sh_entsize"]):
entry = {}
load_struct(buffer, entry, elf64_rel_format)
r_info = entry["r_info"]
entry["r_symbol"] = r_info >> 32
entry["r_type"] = r_info & 0xffffffff
r1_list.append(entry)
elf["rel"][rel["sh_name"]] = r1_list
def read_rela(elf, buffer):
sections = elf["sections"]
rela_list = []
for section in sections:
if section["sh_type"] == SHT_RELA:
rela_list.append(section)
elf["rela"] = {}
elf_type = elf["elf_header"]["file_class"]
symtab = elf["symtabs"][".dynsym"]
for rela in rela_list:
r2_list = []
buffer.seek(rela["sh_offset"])
if elf_type == ELFCLASS32:
for i in range(rela["sh_size"] / rela["sh_entsize"]):
entry = {}
load_struct(buffer, entry, elf32_rela_format)
r_info = entry["r_info"]
entry["r_symbol"] = r_info >> 8
entry["r_type"] = r_info & 0xff
r2_list.append(entry)
else:
for i in range(rela["sh_size"] / rela["sh_entsize"]):
entry = {}
load_struct(buffer, entry, elf64_rela_format)
r_info = entry["r_info"]
entry["r_symbol"] = r_info >> 32
entry["r_type"] = r_info & 0xffffffff
r2_list.append(entry)
elf["rela"][rela["sh_name"]] = r2_list
def read_dynamic(elf, buffer):
sections = elf["sections"]
dynamic = None
for section in sections:
if section["sh_type"] == SHT_DYNAMIC:
dynamic = section
dynamic_list = elf["dynamic"]
buffer.seek(dynamic["sh_offset"])
total = dynamic["sh_size"] / dynamic["sh_entsize"]
if elf["elf_header"]["file_class"] == ELFCLASS32:
for entry in range(total):
dtag, value = struct.unpack("II", buffer.read(ELF64))
dynamic_list.append({dtag: value})
if not dtag:
break
else:
for entry in range(total):
dtag, value = struct.unpack("QQ", buffer.read(2*ELF64))
dynamic_list.append({dtag: value})
if not dtag:
break
in_symtab = [DT_NEEDED, DT_SONAME, DT_RPATH]
strtabs = elf["strtabs"]
strtab = {}
dyntab = {}
if ".strtab" in strtabs:
strtab = strtabs[".strtab"]
if ".dynstr" in strtabs:
dyntab = strtabs[".dynstr"]
for entry in dynamic_list:
d_tag = entry.keys()[0]
if d_tag in in_symtab:
if not d_tag:
continue
value = entry[d_tag]
if not value:
continue
if value in strtab:
name = strtab[value]
elif value in dyntab:
name = dyntab[value]
entry[d_tag] = name
def read_versym(elf, buffer):
sections = elf["sections"]
versym = None
for section in sections:
if section["sh_type"] == SHT_GNU_versym:
versym = section
break
if not versym:
elf["versym"] = []
return
#seek and read
buffer.seek(versym["sh_offset"])
total = versym["sh_size"] / versym["sh_entsize"]
verlist = []
for entry in range(total):
verlist.append(struct.unpack("H", buffer.read(2))[0])
elf["versym"] = verlist
def read_verdef(elf, buffer):
sections = elf["sections"]
verdef = None
for section in sections:
if section["sh_type"] == SHT_GNU_verdef:
verdef = section
break
if not verdef:
elf["verdef"] = []
return
buffer.seek(verdef["sh_offset"])
if not verdef["sh_size"]:
#nothing here
return
symtab = elf["strtabs"][sections[verdef["sh_link"]]["sh_name"]]
deflist = []
while True:
entry = {}
load_struct(buffer, entry, verdef_format)
vs = []
if entry["vd_aux"] != 0:
while True:
verdaux = {}
load_struct(buffer, verdaux, verdaux_format)
vs.append(verdaux)
verdaux["vda_name"] = symtab[verdaux["vda_name"]]
if verdaux["vda_next"] == 0:
break
entry["verdaux"] = vs
deflist.append(entry)
if entry["vd_next"] == 0:
break
elf["verdef"] = deflist
def read_verneed(elf, buffer):
sections = elf["sections"]
verneed = None
for section in sections:
if section["sh_type"] == SHT_GNU_verneed:
verneed = section
break
if not verneed:
elf["verneed"] = []
elf["verindex"] = {}
return
buffer.seek(verneed["sh_offset"])
if not verneed["sh_size"]:
#nothing here
return
symtab = elf["strtabs"][sections[verneed["sh_link"]]["sh_name"]]
deflist = []
while True:
entry = {}
load_struct(buffer, entry, verneed_format)
vs = []
if entry["vn_aux"] != 0:
while True:
vernaux = {}
load_struct(buffer, vernaux, vernaux_format)
vs.append(vernaux)
vernaux["vna_name"] = symtab[vernaux["vna_name"]]
if vernaux["vna_next"] == 0:
break
entry["vernaux"] = vs
entry["vn_file"] = symtab[entry["vn_file"]]
deflist.append(entry)
if entry["vn_next"] == 0:
break
elf["verneed"] = deflist
verindex = {}
if "verindex" in elf:
verindex = elf["verindex"]
for i in deflist:
for j in i["vernaux"]:
verindex[j["vna_other"]] = j
elf["verindex"] = verindex
def read_section(buffer, name):
sections = elf["sections"]
target = None
for section in sections:
if section["sh_name"] == name:
target = section
break
if not target:
raise Exception("No section %s" % target)
buffer.seek(target["sh_offset"])
elf["target"] = buffer.read(target["sh_size"])
def has_sections(debug_list, section_names):
ret = True
for d in debug_list:
if d not in section_names:
ret = False
break
return ret
def get_sections(name_list, sections):
ret_list = []
section_names = [x["name"] for x in sections]
for name in name_list:
ret_list.append(sections[section_names.index(name)])
return ret_list
def read_debugabbr(elf, buffer):
sections = elf["sections"]
debug_abbr = ".debug_abbrev"
if debug_abbr not in sections:
raise ValueError("need .debug_abbrev?")
debug_abbr = sections[".debug_abbrev"]
buffer.seek(debug_abbr["offset"])
def readelf(path, flags, *args):
elf = {
"elf_header": {},
"sections": [],
"programs": [],
"interpreter": "",
"strtabs": {},
"symtabs": {},
"dynamic": [],
"compile_units": [],
"target": None
}
flags |= ELF_HEADER
if flags & ELF_RELA:
flags |= ELF_SYMBOL
if flags & ELF_DYNAMIC:
flags |= ELF_SYMBOL
if flags & ELF_SYMBOL:
flags |= ELF_VERNEED
f = open(path, "rb")
buffer = mmap.mmap(f.fileno(), 0, mmap.MAP_PRIVATE, mmap.PROT_READ)
if flags & ELF_HEADER:
read_header(elf, buffer)
read_section_header(elf, buffer)
read_program_header(elf, buffer)
read_strtab(elf, buffer)
if flags & ELF_SYMBOL:
read_symtab(elf, buffer)
if flags & ELF_DYNAMIC:
read_dynamic(elf, buffer)
if flags & ELF_RELA:
read_rel(elf, buffer)
read_rela(elf, buffer)
if flags & DWARF_INFO: