external/bsd/file/dist/python/magic.py

   1 #!/usr/bin/env python
   2 '''
   3 Python bindings for libmagic
   4 '''
   5
   6 import ctypes
   7
   8 from ctypes import *
   9 from ctypes.util import find_library
  10
  11
  12 def _init():
  13     """
  14     Loads the shared library through ctypes and returns a library
  15     L{ctypes.CDLL} instance
  16     """
  17     return ctypes.cdll.LoadLibrary(find_library('magic'))
  18
  19 _libraries = {}
  20 _libraries['magic'] = _init()
  21
  22 # Flag constants for open and setflags
  23 MAGIC_NONE = NONE = 0
  24 MAGIC_DEBUG = DEBUG = 1
  25 MAGIC_SYMLINK = SYMLINK = 2
  26 MAGIC_COMPRESS = COMPRESS = 4
  27 MAGIC_DEVICES = DEVICES = 8
  28 MAGIC_MIME_TYPE = MIME_TYPE = 16
  29 MAGIC_CONTINUE = CONTINUE = 32
  30 MAGIC_CHECK = CHECK = 64
  31 MAGIC_PRESERVE_ATIME = PRESERVE_ATIME = 128
  32 MAGIC_RAW = RAW = 256
  33 MAGIC_ERROR = ERROR = 512
  34 MAGIC_MIME_ENCODING = MIME_ENCODING = 1024
  35 MAGIC_MIME = MIME = 1040
  36 MAGIC_APPLE = APPLE = 2048
  37
  38 MAGIC_NO_CHECK_COMPRESS = NO_CHECK_COMPRESS = 4096
  39 MAGIC_NO_CHECK_TAR = NO_CHECK_TAR = 8192
  40 MAGIC_NO_CHECK_SOFT = NO_CHECK_SOFT = 16384
  41 MAGIC_NO_CHECK_APPTYPE = NO_CHECK_APPTYPE = 32768
  42 MAGIC_NO_CHECK_ELF = NO_CHECK_ELF = 65536
  43 MAGIC_NO_CHECK_TEXT = NO_CHECK_TEXT = 131072
  44 MAGIC_NO_CHECK_CDF = NO_CHECK_CDF = 262144
  45 MAGIC_NO_CHECK_TOKENS = NO_CHECK_TOKENS = 1048576
  46 MAGIC_NO_CHECK_ENCODING = NO_CHECK_ENCODING = 2097152
  47
  48 MAGIC_NO_CHECK_BUILTIN = NO_CHECK_BUILTIN = 4173824
  49
  50
  51 class magic_set(Structure):
  52     pass
  53 magic_set._fields_ = []
  54 magic_t = POINTER(magic_set)
  55
  56 _open = _libraries['magic'].magic_open
  57 _open.restype = magic_t
  58 _open.argtypes = [c_int]
  59
  60 _close = _libraries['magic'].magic_close
  61 _close.restype = None
  62 _close.argtypes = [magic_t]
  63
  64 _file = _libraries['magic'].magic_file
  65 _file.restype = c_char_p
  66 _file.argtypes = [magic_t, c_char_p]
  67
  68 _descriptor = _libraries['magic'].magic_descriptor
  69 _descriptor.restype = c_char_p
  70 _descriptor.argtypes = [magic_t, c_int]
  71
  72 _buffer = _libraries['magic'].magic_buffer
  73 _buffer.restype = c_char_p
  74 _buffer.argtypes = [magic_t, c_void_p, c_size_t]
  75
  76 _error = _libraries['magic'].magic_error
  77 _error.restype = c_char_p
  78 _error.argtypes = [magic_t]
  79
  80 _setflags = _libraries['magic'].magic_setflags
  81 _setflags.restype = c_int
  82 _setflags.argtypes = [magic_t, c_int]
  83
  84 _load = _libraries['magic'].magic_load
  85 _load.restype = c_int
  86 _load.argtypes = [magic_t, c_char_p]
  87
  88 _compile = _libraries['magic'].magic_compile
  89 _compile.restype = c_int
  90 _compile.argtypes = [magic_t, c_char_p]
  91
  92 _check = _libraries['magic'].magic_check
  93 _check.restype = c_int
  94 _check.argtypes = [magic_t, c_char_p]
  95
  96 _list = _libraries['magic'].magic_list
  97 _list.restype = c_int
  98 _list.argtypes = [magic_t, c_char_p]
  99
 100 _errno = _libraries['magic'].magic_errno
 101 _errno.restype = c_int
 102 _errno.argtypes = [magic_t]
 103
 104
 105 class Magic(object):
 106     def __init__(self, ms):
 107         self._magic_t = ms
 108
 109     def close(self):
 110         """
 111         Closes the magic database and deallocates any resources used.
 112         """
 113         _close(self._magic_t)
 114
 115     def file(self, filename):
 116         """
 117         Returns a textual description of the contents of the argument passed
 118         as a filename or None if an error occurred and the MAGIC_ERROR flag
 119         is set.  A call to errno() will return the numeric error code.
 120         """
 121         try:  # attempt python3 approach first
 122             if isinstance(filename, bytes):
 123                 bi = filename
 124             else:
 125                 bi = bytes(filename, 'utf-8')
 126             return str(_file(self._magic_t, bi), 'utf-8')
 127         except:
 128             return _file(self._magic_t, filename.encode('utf-8'))
 129
 130     def descriptor(self, fd):
 131         """
 132         Like the file method, but the argument is a file descriptor.
 133         """
 134         return _descriptor(self._magic_t, fd)
 135
 136     def buffer(self, buf):
 137         """
 138         Returns a textual description of the contents of the argument passed
 139         as a buffer or None if an error occurred and the MAGIC_ERROR flag
 140         is set. A call to errno() will return the numeric error code.
 141         """
 142         try:  # attempt python3 approach first
 143             return str(_buffer(self._magic_t, buf, len(buf)), 'utf-8')
 144         except:
 145             return _buffer(self._magic_t, buf, len(buf))
 146
 147     def error(self):
 148         """
 149         Returns a textual explanation of the last error or None
 150         if there was no error.
 151         """
 152         try:  # attempt python3 approach first
 153             return str(_error(self._magic_t), 'utf-8')
 154         except:
 155             return _error(self._magic_t)
 156
 157     def setflags(self, flags):
 158         """
 159         Set flags on the magic object which determine how magic checking
 160         behaves; a bitwise OR of the flags described in libmagic(3), but
 161         without the MAGIC_ prefix.
 162
 163         Returns -1 on systems that don't support utime(2) or utimes(2)
 164         when PRESERVE_ATIME is set.
 165         """
 166         return _setflags(self._magic_t, flags)
 167
 168     def load(self, filename=None):
 169         """
 170         Must be called to load entries in the colon separated list of database
 171         files passed as argument or the default database file if no argument
 172         before any magic queries can be performed.
 173
 174         Returns 0 on success and -1 on failure.
 175         """
 176         return _load(self._magic_t, filename)
 177
 178     def compile(self, dbs):
 179         """
 180         Compile entries in the colon separated list of database files
 181         passed as argument or the default database file if no argument.
 182         Returns 0 on success and -1 on failure.
 183         The compiled files created are named from the basename(1) of each file
 184         argument with ".mgc" appended to it.
 185         """
 186         return _compile(self._magic_t, dbs)
 187
 188     def check(self, dbs):
 189         """
 190         Check the validity of entries in the colon separated list of
 191         database files passed as argument or the default database file
 192         if no argument.
 193         Returns 0 on success and -1 on failure.
 194         """
 195         return _check(self._magic_t, dbs)
 196
 197     def list(self, dbs):
 198         """
 199         Check the validity of entries in the colon separated list of
 200         database files passed as argument or the default database file
 201         if no argument.
 202         Returns 0 on success and -1 on failure.
 203         """
 204         return _list(self._magic_t, dbs)
 205
 206     def errno(self):
 207         """
 208         Returns a numeric error code. If return value is 0, an internal
 209         magic error occurred. If return value is non-zero, the value is
 210         an OS error code. Use the errno module or os.strerror() can be used
 211         to provide detailed error information.
 212         """
 213         return _errno(self._magic_t)
 214
 215
 216 def open(flags):
 217     """
 218     Returns a magic object on success and None on failure.
 219     Flags argument as for setflags.
 220     """
 221     return Magic(_open(flags))