contrib/devtools/symbol-check.py

   1 #!/usr/bin/python2
   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
  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 '_edata', '_end', '_init', '__bss_start', '_fini', '_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 'libgcc_s.so.1', # GCC base support
  58 'libc.so.6', # C library
  59 'libpthread.so.0', # threading
  60 'libanl.so.1', # DNS resolve
  61 'libm.so.6', # math library
  62 'librt.so.1', # real-time (clock)
  63 'ld-linux-x86-64.so.2', # 64-bit dynamic linker
  64 'ld-linux.so.2', # 32-bit dynamic linker
  65 # bitcoin-qt only
  66 'libX11-xcb.so.1', # part of X11
  67 'libX11.so.6', # part of X11
  68 'libxcb.so.1', # part of X11
  69 'libfontconfig.so.1', # font support
  70 'libfreetype.so.6', # font parsing
  71 '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 + '\n')
  85         return self.proc.stdout.readline().rstrip()
  86
  87     def close(self):
  88         self.proc.stdin.close()
  89         self.proc.stdout.close()
  90         self.proc.wait()
  91
  92 def read_symbols(executable, imports=True):
  93     '''
  94     Parse an ELF executable and return a list of (symbol,version) tuples
  95     for dynamic, imported symbols.
  96     '''
  97     p = subprocess.Popen([READELF_CMD, '--dyn-syms', '-W', executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
  98     (stdout, stderr) = p.communicate()
  99     if p.returncode:
 100         raise IOError('Could not read symbols for %s: %s' % (executable, stderr.strip()))
 101     syms = []
 102     for line in stdout.split('\n'):
 103         line = line.split()
 104         if len(line)>7 and re.match('[0-9]+:$', line[0]):
 105             (sym, _, version) = line[7].partition('@')
 106             is_import = line[6] == 'UND'
 107             if version.startswith('@'):
 108                 version = version[1:]
 109             if is_import == imports:
 110                 syms.append((sym, version))
 111     return syms
 112
 113 def check_version(max_versions, version):
 114     if '_' in version:
 115         (lib, _, ver) = version.rpartition('_')
 116     else:
 117         lib = version
 118         ver = '0'
 119     ver = tuple([int(x) for x in ver.split('.')])
 120     if not lib in max_versions:
 121         return False
 122     return ver <= max_versions[lib]
 123
 124 def read_libraries(filename):
 125     p = subprocess.Popen([READELF_CMD, '-d', '-W', filename], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
 126     (stdout, stderr) = p.communicate()
 127     if p.returncode:
 128         raise IOError('Error opening file')
 129     libraries = []
 130     for line in stdout.split('\n'):
 131         tokens = line.split()
 132         if len(tokens)>2 and tokens[1] == '(NEEDED)':
 133             match = re.match('^Shared library: \[(.*)\]$', ' '.join(tokens[2:]))
 134             if match:
 135                 libraries.append(match.group(1))
 136             else:
 137                 raise ValueError('Unparseable (NEEDED) specification')
 138     return libraries
 139
 140 if __name__ == '__main__':
 141     cppfilt = CPPFilt()
 142     retval = 0
 143     for filename in sys.argv[1:]:
 144         # Check imported symbols
 145         for sym,version in read_symbols(filename, True):
 146             if version and not check_version(MAX_VERSIONS, version):
 147                 print('%s: symbol %s from unsupported version %s' % (filename, cppfilt(sym), version))
 148                 retval = 1
 149         # Check exported symbols
 150         for sym,version in read_symbols(filename, False):
 151             if sym in IGNORE_EXPORTS:
 152                 continue
 153             print('%s: export of symbol %s not allowed' % (filename, cppfilt(sym)))
 154             retval = 1
 155         # Check dependency libraries
 156         for library_name in read_libraries(filename):
 157             if library_name not in ALLOWED_LIBRARIES:
 158                 print('%s: NEEDED library %s is not allowed' % (filename, library_name))
 159                 retval = 1
 160
 161     exit(retval)
 162
 163