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, lib):
  23     '''
  24     List all the (non platform-specific) symbols exported by the library
  25     '''
  26     symbols = []
  27     platform_name = platform.system()
  28     output = subprocess.check_output([nm, '-gP', lib],
  29                                      stderr=open(os.devnull, 'w')).decode("ascii")
  30     for line in output.splitlines():
  31         fields = line.split()
  32         if len(fields) == 2 or fields[1] == 'U':
  33             continue
  34         symbol_name = fields[0]
  35         if platform_name == 'Linux':
  36             if symbol_name in PLATFORM_SYMBOLS:
  37                 continue
  38         elif platform_name == 'Darwin':
  39             assert symbol_name[0] == '_'
  40             symbol_name = symbol_name[1:]
  41         symbols.append(symbol_name)
  42
  43     return symbols
  44
  45
  46 def main():
  47     parser = argparse.ArgumentParser()
  48     parser.add_argument('--symbols-file',
  49                         action='store',
  50                         required=True,
  51                         help='path to file containing symbols')
  52     parser.add_argument('--lib',
  53                         action='store',
  54                         required=True,
  55                         help='path to library')
  56     parser.add_argument('--nm',
  57                         action='store',
  58                         required=True,
  59                         help='path to binary (or name in $PATH)')
  60     args = parser.parse_args()
  61
  62     try:
  63         lib_symbols = get_symbols(args.nm, args.lib)
  64     except:
  65         # We can't run this test, but we haven't technically failed it either
  66         # Return the GNU "skip" error code
  67         exit(77)
  68     mandatory_symbols = []
  69     optional_symbols = []
  70     with open(args.symbols_file) as symbols_file:
  71         qualifier_optional = '(optional)'
  72         for line in symbols_file.readlines():
  73
  74             # Strip comments
  75             line = line.split('#')[0]
  76             line = line.strip()
  77             if not line:
  78                 continue
  79
  80             # Line format:
  81             # [qualifier] symbol
  82             qualifier = None
  83             symbol = None
  84
  85             fields = line.split()
  86             if len(fields) == 1:
  87                 symbol = fields[0]
  88             elif len(fields) == 2:
  89                 qualifier = fields[0]
  90                 symbol = fields[1]
  91             else:
  92                 print(args.symbols_file + ': invalid format: ' + line)
  93                 exit(1)
  94
  95             # The only supported qualifier is 'optional', which means the
  96             # symbol doesn't have to be exported by the library
  97             if qualifier and not qualifier == qualifier_optional:
  98                 print(args.symbols_file + ': invalid qualifier: ' + qualifier)
  99                 exit(1)
 100
 101             if qualifier == qualifier_optional:
 102                 optional_symbols.append(symbol)
 103             else:
 104                 mandatory_symbols.append(symbol)
 105
 106     unknown_symbols = []
 107     for symbol in lib_symbols:
 108         if symbol in mandatory_symbols:
 109             continue
 110         if symbol in optional_symbols:
 111             continue
 112         if symbol[:2] == '_Z':
 113             # Ignore random C++ symbols
 114             #TODO: figure out if there's any way to avoid exporting them in the first place
 115             continue
 116         unknown_symbols.append(symbol)
 117
 118     missing_symbols = [
 119         sym for sym in mandatory_symbols if sym not in lib_symbols
 120     ]
 121
 122     for symbol in unknown_symbols:
 123         print(args.lib + ': unknown symbol exported: ' + symbol)
 124
 125     for symbol in missing_symbols:
 126         print(args.lib + ': missing symbol: ' + symbol)
 127
 128     if unknown_symbols or missing_symbols:
 129         exit(1)
 130     exit(0)
 131
 132
 133 if __name__ == '__main__':
 134     main()