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