bin/symbols-check.py

   1 #!/usr/bin/env python
   2
   3 import argparse
   4 import os
   5 import platform
   6 import subprocess
   7
   8 # This list contains symbols that _might_ be exported for some platforms
   9 PLATFORM_SYMBOLS = [
  10     '__bss_end__',
  11     '__bss_start__',
  12     '__bss_start',
  13     '__end__',
  14     '_bss_end__',
  15     '_edata',
  16     '_end',
  17     '_fini',
  18     '_init',
  19 ]
  20
  21
  22 def get_symbols_nm(nm, lib):
  23     '''
  24     List all the (non platform-specific) symbols exported by the library
  25     using `nm`
  26     '''
  27     symbols = []
  28     platform_name = platform.system()
  29     output = subprocess.check_output([nm, '-gP', lib],
  30                                      stderr=open(os.devnull, 'w')).decode("ascii")
  31     for line in output.splitlines():
  32         fields = line.split()
  33         if len(fields) == 2 or fields[1] == 'U':
  34             continue
  35         symbol_name = fields[0]
  36         if platform_name == 'Linux':
  37             if symbol_name in PLATFORM_SYMBOLS:
  38                 continue
  39         elif platform_name == 'Darwin':
  40             assert symbol_name[0] == '_'
  41             symbol_name = symbol_name[1:]
  42         symbols.append(symbol_name)
  43     return symbols
  44
  45
  46 def get_symbols_dumpbin(dumpbin, lib):
  47     '''
  48     List all the (non platform-specific) symbols exported by the library
  49     using `dumpbin`
  50     '''
  51     symbols = []
  52     output = subprocess.check_output([dumpbin, '/exports', lib],
  53                                      stderr=open(os.devnull, 'w')).decode("ascii")
  54     for line in output.splitlines():
  55         fields = line.split()
  56         # The lines with the symbols are made of at least 4 columns; see details below
  57         if len(fields) < 4:
  58             continue
  59         try:
  60             # Making sure the first 3 columns are a dec counter, a hex counter
  61             # and a hex address
  62             _ = int(fields[0], 10)
  63             _ = int(fields[1], 16)
  64             _ = int(fields[2], 16)
  65         except ValueError:
  66             continue
  67         symbol_name = fields[3]
  68         # De-mangle symbols
  69         if symbol_name[0] == '_':
  70             symbol_name = symbol_name[1:].split('@')[0]
  71         symbols.append(symbol_name)
  72     return symbols
  73
  74
  75 def main():
  76     parser = argparse.ArgumentParser()
  77     parser.add_argument('--symbols-file',
  78                         action='store',
  79                         required=True,
  80                         help='path to file containing symbols')
  81     parser.add_argument('--lib',
  82                         action='store',
  83                         required=True,
  84                         help='path to library')
  85     parser.add_argument('--nm',
  86                         action='store',
  87                         help='path to binary (or name in $PATH)')
  88     parser.add_argument('--dumpbin',
  89                         action='store',
  90                         help='path to binary (or name in $PATH)')
  91     args = parser.parse_args()
  92
  93     try:
  94         if platform.system() == 'Windows':
  95             if not args.dumpbin:
  96                 parser.error('--dumpbin is mandatory')
  97             lib_symbols = get_symbols_dumpbin(args.dumpbin, args.lib)
  98         else:
  99             if not args.nm:
 100                 parser.error('--nm is mandatory')
 101             lib_symbols = get_symbols_nm(args.nm, args.lib)
 102     except:
 103         # We can't run this test, but we haven't technically failed it either
 104         # Return the GNU "skip" error code
 105         exit(77)
 106     mandatory_symbols = []
 107     optional_symbols = []
 108     with open(args.symbols_file) as symbols_file:
 109         qualifier_optional = '(optional)'
 110         for line in symbols_file.readlines():
 111
 112             # Strip comments
 113             line = line.split('#')[0]
 114             line = line.strip()
 115             if not line:
 116                 continue
 117
 118             # Line format:
 119             # [qualifier] symbol
 120             qualifier = None
 121             symbol = None
 122
 123             fields = line.split()
 124             if len(fields) == 1:
 125                 symbol = fields[0]
 126             elif len(fields) == 2:
 127                 qualifier = fields[0]
 128                 symbol = fields[1]
 129             else:
 130                 print(args.symbols_file + ': invalid format: ' + line)
 131                 exit(1)
 132
 133             # The only supported qualifier is 'optional', which means the
 134             # symbol doesn't have to be exported by the library
 135             if qualifier and not qualifier == qualifier_optional:
 136                 print(args.symbols_file + ': invalid qualifier: ' + qualifier)
 137                 exit(1)
 138
 139             if qualifier == qualifier_optional:
 140                 optional_symbols.append(symbol)
 141             else:
 142                 mandatory_symbols.append(symbol)
 143
 144     unknown_symbols = []
 145     for symbol in lib_symbols:
 146         if symbol in mandatory_symbols:
 147             continue
 148         if symbol in optional_symbols:
 149             continue
 150         if symbol[:2] == '_Z':
 151             # As ajax found out, the compiler intentionally exports symbols
 152             # that we explicitely asked it not to export, and we can't do
 153             # anything about it:
 154             # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36022#c4
 155             continue
 156         unknown_symbols.append(symbol)
 157
 158     missing_symbols = [
 159         sym for sym in mandatory_symbols if sym not in lib_symbols
 160     ]
 161
 162     for symbol in unknown_symbols:
 163         print(args.lib + ': unknown symbol exported: ' + symbol)
 164
 165     for symbol in missing_symbols:
 166         print(args.lib + ': missing symbol: ' + symbol)
 167
 168     if unknown_symbols or missing_symbols:
 169         exit(1)
 170     exit(0)
 171
 172
 173 if __name__ == '__main__':
 174     main()