Get meta information of images

author_utils.py

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+import ctypes as ctypes
+from ctypes import wintypes as wintypes
+import os
+import sys
+
+
+kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)
+advapi32 = ctypes.WinDLL('advapi32', use_last_error=True)
+
+ERROR_INVALID_FUNCTION  = 0x0001
+ERROR_FILE_NOT_FOUND    = 0x0002
+ERROR_PATH_NOT_FOUND    = 0x0003
+ERROR_ACCESS_DENIED     = 0x0005
+ERROR_SHARING_VIOLATION = 0x0020
+
+SE_FILE_OBJECT = 1
+OWNER_SECURITY_INFORMATION = 0x00000001
+GROUP_SECURITY_INFORMATION = 0x00000002
+DACL_SECURITY_INFORMATION  = 0x00000004
+SACL_SECURITY_INFORMATION  = 0x00000008
+LABEL_SECURITY_INFORMATION = 0x00000010
+
+_DEFAULT_SECURITY_INFORMATION = (OWNER_SECURITY_INFORMATION |
+    GROUP_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION |
+    LABEL_SECURITY_INFORMATION)
+
+LPDWORD = ctypes.POINTER(wintypes.DWORD)
+SE_OBJECT_TYPE = wintypes.DWORD
+SECURITY_INFORMATION = wintypes.DWORD
+
+class SID_NAME_USE(wintypes.DWORD):
+    _sid_types = dict(enumerate('''
+        User Group Domain Alias WellKnownGroup DeletedAccount
+        Invalid Unknown Computer Label'''.split(), 1))
+
+    def __init__(self, value=None):
+        if value is not None:
+            if value not in self.sid_types:
+                raise ValueError('invalid SID type')
+            wintypes.DWORD.__init__(value)
+
+    def __str__(self):
+        if self.value not in self._sid_types:
+            raise ValueError('invalid SID type')
+        return self._sid_types[self.value]
+
+    def __repr__(self):
+        return 'SID_NAME_USE(%s)' % self.value
+
+PSID_NAME_USE = ctypes.POINTER(SID_NAME_USE)
+
+class PLOCAL(wintypes.LPVOID):
+    _needs_free = False
+    def __init__(self, value=None, needs_free=False):
+        super(PLOCAL, self).__init__(value)
+        self._needs_free = needs_free
+
+    def __del__(self):
+        if self and self._needs_free:
+            kernel32.LocalFree(self)
+            self._needs_free = False
+
+PACL = PLOCAL
+
+class PSID(PLOCAL):
+    def __init__(self, value=None, needs_free=False):
+        super(PSID, self).__init__(value, needs_free)
+
+    def __str__(self):
+        if not self:
+            raise ValueError('NULL pointer access')
+        sid = wintypes.LPWSTR()
+        advapi32.ConvertSidToStringSidW(self, ctypes.byref(sid))
+        try:
+            return sid.value
+        finally:
+            if sid:
+                kernel32.LocalFree(sid)
+
+class PSECURITY_DESCRIPTOR(PLOCAL):
+    def __init__(self, value=None, needs_free=False):
+        super(PSECURITY_DESCRIPTOR, self).__init__(value, needs_free)
+        self.pOwner = PSID()
+        self.pGroup = PSID()
+        self.pDacl = PACL()
+        self.pSacl = PACL()
+        # back references to keep this object alive
+        self.pOwner._SD = self
+        self.pGroup._SD = self
+        self.pDacl._SD = self
+        self.pSacl._SD = self
+
+    def get_owner(self, system_name=None):
+        if not self or not self.pOwner:
+            raise ValueError('NULL pointer access')
+        return look_up_account_sid(self.pOwner, system_name)
+
+    def get_group(self, system_name=None):
+        if not self or not self.pGroup:
+            raise ValueError('NULL pointer access')
+        return look_up_account_sid(self.pGroup, system_name)
+
+def _check_bool(result, func, args):
+    if not result:
+        raise ctypes.WinError(ctypes.get_last_error())
+    return args
+
+# msdn.microsoft.com/en-us/library/aa376399
+advapi32.ConvertSidToStringSidW.errcheck = _check_bool
+advapi32.ConvertSidToStringSidW.argtypes = (
+    PSID, # _In_   Sid
+    ctypes.POINTER(wintypes.LPWSTR)) # _Out_ StringSid
+
+# msdn.microsoft.com/en-us/library/aa379166
+advapi32.LookupAccountSidW.errcheck = _check_bool
+advapi32.LookupAccountSidW.argtypes = (
+    wintypes.LPCWSTR, # _In_opt_  lpSystemName
+    PSID,             # _In_      lpSid
+    wintypes.LPCWSTR, # _Out_opt_ lpName
+    LPDWORD,          # _Inout_   cchName
+    wintypes.LPCWSTR, # _Out_opt_ lpReferencedDomainName
+    LPDWORD,          # _Inout_   cchReferencedDomainName
+    PSID_NAME_USE)    # _Out_     peUse
+
+# msdn.microsoft.com/en-us/library/aa446645
+advapi32.GetNamedSecurityInfoW.restype = wintypes.DWORD
+advapi32.GetNamedSecurityInfoW.argtypes = (
+    wintypes.LPWSTR,       # _In_      pObjectName
+    SE_OBJECT_TYPE,        # _In_      ObjectType
+    SECURITY_INFORMATION,  # _In_      SecurityInfo
+    ctypes.POINTER(PSID),  # _Out_opt_ ppsidOwner
+    ctypes.POINTER(PSID),  # _Out_opt_ ppsidGroup
+    ctypes.POINTER(PACL),  # _Out_opt_ ppDacl
+    ctypes.POINTER(PACL),  # _Out_opt_ ppSacl
+    ctypes.POINTER(PSECURITY_DESCRIPTOR)) # _Out_opt_ ppSecurityDescriptor  
+
+def look_up_account_sid(sid, system_name=None):
+    SIZE = 256
+    name = ctypes.create_unicode_buffer(SIZE)
+    domain = ctypes.create_unicode_buffer(SIZE)
+    cch_name = wintypes.DWORD(SIZE)
+    cch_domain = wintypes.DWORD(SIZE)
+    sid_type = SID_NAME_USE()
+    advapi32.LookupAccountSidW(system_name, sid, name, ctypes.byref(cch_name),
+        domain, ctypes.byref(cch_domain), ctypes.byref(sid_type))
+    return name.value, domain.value, sid_type
+
+def get_file_security(filename, request=_DEFAULT_SECURITY_INFORMATION):
+    # N.B. This query may fail with ERROR_INVALID_FUNCTION
+    # for some filesystems.
+    pSD = PSECURITY_DESCRIPTOR(needs_free=True)
+    error = advapi32.GetNamedSecurityInfoW(filename, SE_FILE_OBJECT, request,
+                ctypes.byref(pSD.pOwner), ctypes.byref(pSD.pGroup),
+                ctypes.byref(pSD.pDacl), ctypes.byref(pSD.pSacl),
+                ctypes.byref(pSD))
+    if error != 0:
+        raise ctypes.WinError(error)
+    return pSD
+
+def get_author(filename):
+    if isinstance(filename, bytes):
+        if hasattr(os, 'fsdecode'):
+            filename = os.fsdecode(filename)
+        else:
+            filename = filename.decode(sys.getfilesystemencoding())
+
+    pSD = get_file_security(filename)
+    owner_name, owner_domain, owner_sid_type = pSD.get_owner()
+    if owner_domain:
+        owner_name = '{}\\{}'.format(owner_domain, owner_name)
+    return owner_name