contrib/devtools/symbol-check.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2014 Wladimir J. van der Laan
   3 # Distributed under the MIT software license, see the accompanying
   4 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5 '''
   6 A script to check that the (Linux) executables produced by gitian only contain
   7 allowed gcc, glibc and libstdc++ version symbols.  This makes sure they are
   8 still compatible with the minimum supported Linux distribution versions.
   9
  10 Example usage:
  11
  12     find ../gitian-builder/build -type f -executable | xargs python contrib/devtools/symbol-check.py
  13 '''
  14 from __future__ import division, print_function, unicode_literals
  15 import subprocess
  16 import re
  17 import sys
  18 import os
  19
  20 # Debian 6.0.9 (Squeeze) has:
  21 #
  22 # - g++ version 4.4.5 (https://packages.debian.org/search?suite=default&section=all&arch=any&searchon=names&keywords=g%2B%2B)
  23 # - libc version 2.11.3 (https://packages.debian.org/search?suite=default&section=all&arch=any&searchon=names&keywords=libc6)
  24 # - libstdc++ version 4.4.5 (https://packages.debian.org/search?suite=default&section=all&arch=any&searchon=names&keywords=libstdc%2B%2B6)
  25 #
  26 # Ubuntu 10.04.4 (Lucid Lynx) has:
  27 #
  28 # - g++ version 4.4.3 (http://packages.ubuntu.com/search?keywords=g%2B%2B&searchon=names&suite=lucid&section=all)
  29 # - libc version 2.11.1 (http://packages.ubuntu.com/search?keywords=libc6&searchon=names&suite=lucid&section=all)
  30 # - libstdc++ version 4.4.3 (http://packages.ubuntu.com/search?suite=lucid&section=all&arch=any&keywords=libstdc%2B%2B&searchon=names)
  31 #
  32 # Taking the minimum of these as our target.
  33 #
  34 # According to GNU ABI document (http://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html) this corresponds to:
  35 #   GCC 4.4.0: GCC_4.4.0
  36 #   GCC 4.4.2: GLIBCXX_3.4.13, CXXABI_1.3.3
  37 #   (glibc)    GLIBC_2_11
  38 #
  39 MAX_VERSIONS = {
  40 'GCC':     (4,4,0),
  41 'CXXABI':  (1,3,3),
  42 'GLIBCXX': (3,4,13),
  43 'GLIBC':   (2,11)
  44 }
  45 # See here for a description of _IO_stdin_used:
  46 # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=634261#109
  47
  48 # Ignore symbols that are exported as part of every executable
  49 IGNORE_EXPORTS = {
  50 b'_edata', b'_end', b'_init', b'__bss_start', b'_fini', b'_IO_stdin_used'
  51 }
  52 READELF_CMD = os.getenv('READELF', '/usr/bin/readelf')
  53 CPPFILT_CMD = os.getenv('CPPFILT', '/usr/bin/c++filt')
  54 # Allowed NEEDED libraries
  55 ALLOWED_LIBRARIES = {
  56 # bitcoind and bitcoin-qt
  57 b'libgcc_s.so.1', # GCC base support
  58 b'libc.so.6', # C library
  59 b'libpthread.so.0', # threading
  60 b'libanl.so.1', # DNS resolve
  61 b'libm.so.6', # math library
  62 b'librt.so.1', # real-time (clock)
  63 b'ld-linux-x86-64.so.2', # 64-bit dynamic linker
  64 b'ld-linux.so.2', # 32-bit dynamic linker
  65 # bitcoin-qt only
  66 b'libX11-xcb.so.1', # part of X11
  67 b'libX11.so.6', # part of X11
  68 b'libxcb.so.1', # part of X11
  69 b'libfontconfig.so.1', # font support
  70 b'libfreetype.so.6', # font parsing
  71 b'libdl.so.2' # programming interface to dynamic linker
  72 }
  73
  74 class CPPFilt(object):
  75     '''
  76     Demangle C++ symbol names.
  77
  78     Use a pipe to the 'c++filt' command.
  79     '''
  80     def __init__(self):
  81         self.proc = subprocess.Popen(CPPFILT_CMD, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
  82
  83     def __call__(self, mangled):
  84         self.proc.stdin.write(mangled + b'\n')
  85         self.proc.stdin.flush()
  86         return self.proc.stdout.readline().rstrip()
  87
  88     def close(self):
  89         self.proc.stdin.close()
  90         self.proc.stdout.close()
  91         self.proc.wait()
  92
  93 def read_symbols(executable, imports=True):
  94     '''
  95     Parse an ELF executable and return a list of (symbol,version) tuples
  96     for dynamic, imported symbols.
  97     '''
  98     p = subprocess.Popen([READELF_CMD, '--dyn-syms', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
  99     (stdout, stderr) = p.communicate()
 100     if p.returncode:
 101         raise IOError('Could not read symbols for %s: %s' % (executable, stderr.strip()))
 102     syms = []
 103     for line in stdout.split(b'\n'):
 104         line = line.split()
 105         if len(line)>7 and re.match(b'[0-9]+:$', line[0]):
 106             (sym, _, version) = line[7].partition(b'@')
 107             is_import = line[6] == b'UND'
 108             if version.startswith(b'@'):
 109                 version = version[1:]
 110             if is_import == imports:
 111                 syms.append((sym, version))
 112     return syms
 113
 114 def check_version(max_versions, version):
 115     if b'_' in version:
 116         (lib, _, ver) = version.rpartition(b'_')
 117     else:
 118         lib = version
 119         ver = '0'
 120     ver = tuple([int(x) for x in ver.split(b'.')])
 121     if not lib in max_versions:
 122         return False
 123     return ver <= max_versions[lib]
 124
 125 def read_libraries(filename):
 126     p = subprocess.Popen([READELF_CMD, '-d', '-W', filename], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
 127     (stdout, stderr) = p.communicate()
 128     if p.returncode:
 129         raise IOError('Error opening file')
 130     libraries = []
 131     for line in stdout.split(b'\n'):
 132         tokens = line.split()
 133         if len(tokens)>2 and tokens[1] == b'(NEEDED)':
 134             match = re.match(b'^Shared library: \[(.*)\]$', b' '.join(tokens[2:]))
 135             if match:
 136                 libraries.append(match.group(1))
 137             else:
 138                 raise ValueError('Unparseable (NEEDED) specification')
 139     return libraries
 140
 141 if __name__ == '__main__':
 142     cppfilt = CPPFilt()
 143     retval = 0
 144     for filename in sys.argv[1:]:
 145         # Check imported symbols
 146         for sym,version in read_symbols(filename, True):
 147             if version and not check_version(MAX_VERSIONS, version):
 148                 print('%s: symbol %s from unsupported version %s' % (filename, cppfilt(sym).decode('utf-8'), version.decode('utf-8')))
 149                 retval = 1
 150         # Check exported symbols
 151         for sym,version in read_symbols(filename, False):
 152             if sym in IGNORE_EXPORTS:
 153                 continue
 154             print('%s: export of symbol %s not allowed' % (filename, cppfilt(sym).decode('utf-8')))
 155             retval = 1
 156         # Check dependency libraries
 157         for library_name in read_libraries(filename):
 158             if library_name not in ALLOWED_LIBRARIES:
 159                 print('%s: NEEDED library %s is not allowed' % (filename, library_name.decode('utf-8')))
 160                 retval = 1
 161
 162     sys.exit(retval)
 163
 164