1 #-------------------------------------------------------------------------------
2 # elftools example: elf_low_high_api.py
4 # A simple example that shows some usage of the low-level API pyelftools
5 # provides versus the high-level API while inspecting an ELF file's symbol
8 # Eli Bendersky (eliben@gmail.com)
9 # This code is in the public domain
10 #-------------------------------------------------------------------------------
11 from __future__
import print_function
14 # If pyelftools is not installed, the example can also run from the root or
15 # examples/ dir of the source distribution.
16 sys
.path
[0:0] = ['.', '..']
18 from elftools
.elf
.elffile
import ELFFile
19 from elftools
.elf
.sections
import SymbolTableSection
22 def process_file(filename
):
23 print('Processing file:', filename
)
24 with
open(filename
, 'rb') as f
:
25 section_info_lowlevel(f
)
27 section_info_highlevel(f
)
30 def section_info_lowlevel(stream
):
31 print('Low level API...')
32 # We'll still be using the ELFFile context object. It's just too
33 # convenient to give up, even in the low-level API demonstation :-)
34 elffile
= ELFFile(stream
)
36 # The e_shnum ELF header field says how many sections there are in a file
37 print(' %s sections' % elffile
['e_shnum'])
39 # Try to find the symbol table
40 for i
in range(elffile
['e_shnum']):
41 section_offset
= elffile
['e_shoff'] + i
* elffile
['e_shentsize']
42 # Parse the section header using structs.Elf_Shdr
43 stream
.seek(section_offset
)
44 section_header
= elffile
.structs
.Elf_Shdr
.parse_stream(stream
)
45 if section_header
['sh_type'] == 'SHT_SYMTAB':
46 # Some details about the section. Note that the section name is a
47 # pointer to the object's string table, so it's only a number
48 # here. To get to the actual name one would need to parse the string
49 # table section and extract the name from there (or use the
51 print(' Section name: %s, type: %s' % (
52 section_header
['sh_name'], section_header
['sh_type']))
55 print(' No symbol table found. Perhaps this ELF has been stripped?')
58 def section_info_highlevel(stream
):
59 print('High level API...')
60 elffile
= ELFFile(stream
)
62 # Just use the public methods of ELFFile to get what we need
63 # Note that section names are strings.
64 print(' %s sections' % elffile
.num_sections())
65 section
= elffile
.get_section_by_name('.symtab')
68 print(' No symbol table found. Perhaps this ELF has been stripped?')
71 # A section type is in its header, but the name was decoded and placed in
73 print(' Section name: %s, type: %s' %(
74 section
.name
, section
['sh_type']))
76 # But there's more... If this section is a symbol table section (which is
77 # the case in the sample ELF file that comes with the examples), we can
78 # get some more information about it.
79 if isinstance(section
, SymbolTableSection
):
80 num_symbols
= section
.num_symbols()
81 print(" It's a symbol section with %s symbols" % num_symbols
)
82 print(" The name of the last symbol in the section is: %s" % (
83 section
.get_symbol(num_symbols
- 1).name
))
86 if __name__
== '__main__':
87 if sys
.argv
[1] == '--test':
88 for filename
in sys
.argv
[2:]:
89 process_file(filename
)