Several useful functions in Chrome sandbox

// Determine whether the handle and path are the same // we get a | full_path | of the form /?? /C:/Some/Foo/bar, and the name that/we'll get from | handle | will be/device/harddiskvolume1/Some/Foo/bar. bool sameobject (handle, const wchar_t * full_path) {STD: wstring path (full_path); dcheck (! Path. Empty (); // check if it's a pipe. If (ispipe (PATH) return true; STD: wstring actual_path; If (! Getpathfromhandle (handle, & actual_path) return false; // This may end with a backslash. const wchar_t kbackslash = '//'; If (path [path. length ()-1] = kbackslash) Path = path. substr (0, path. length ()-1); // perfect match (case-insesitive check ). if (0 = _ wcsicmp (actual_path.c_str (), path. c_str () return true; // look for the drive letter. size_t colon_pos = path. find (L': '); If (colon_pos = 0 | Colon_pos = STD: wstring: NPOs) return false; // only one character for the drive. If (colon_pos> 1 & path [colon_pos-2]! = Kbackslash) return false; // we only need 3 chars, but let's alloc a buffer for four. wchar_t drive [4] = {0}; wchar_t vol_name [max_path]; memcpy (drive, & path [colon_pos-1], 2 * sizeof (* drive )); // We'll get a double NULL terminated string. DWORD vol_length =: querydosdevicew (drive, vol_name, max_path); If (vol_length <2 | vol_length = max_path) return false; // ignore the nulls at the end. V Ol_length = static_cast (wcslen (vol_name); // The two paths shocould be the same length. If (vol_length + path. Size ()-(colon_pos + 1 )! = Actual_path.size () return false; // check up to the drive letter. If (0! = _ Wcsnicmp (actual_path.c_str (), vol_name, vol_length) return false; // check the path after the drive letter. If (0! = _ Wcsicmp (& actual_path [vol_length], & path [colon_pos + 1]) return false; return true ;} // convert a short path to a long path // convert a short path (C:/path ~ 1 Or //?? // C:/path ~ 1) to the long version of // the path. if the path is not a valid filesystem path, the function returns // false and the output parameter is not modified. bool converttolongpath (const STD: wstring & short_path, STD: wstring * long_path) {// check if the path is a NT path. bool is_nt_path = false; STD: wstring Path = short_path; If (0 = path. compare (0, kntprefixlen, kntprefix) {Path = path. substr (Knt Prefixlen); is_nt_path = true;} DWORD size = max_path; scoped_array long_path_buf (New wchar_t [size]); DWORD return_value =: getlongpathname (path. c_str (), long_path_buf.get (), size); While (return_value> = size) {size * = 2; long_path_buf.reset (New wchar_t [size]); return_value = :: getlongpathname (path. c_str (), long_path_buf.get (), size);} DWORD last_error =: getlasterror (); If (0 = return_valu E & (error_file_not_found = last_error | error_path_not_found = last_error | error_invalid_name = last_error) {// the file does not exist, but maybe a sub path needs to be expanded. STD: wstring: size_type last_slash = path. rfind (L' // '); If (STD: wstring: NPOs = last_slash) return false; STD: wstring begin = path. substr (0, last_slash); STD: wstring end = path. substr (last_slash); If (! Converttolongpath (begin, & begin) return false; // OK, it worked. let's reset the return value. path = begin + end; return_value = 1;} else if (0! = Return_value) {Path = long_path_buf.get ();} If (return_value! = 0) {If (is_nt_path) {* long_path = kntprefix; * long_path + = path;} else {* long_path = path;} return true;} return false ;} // obtain the path bool getpathfromhandle (handle, STD: wstring * path) {ntqueryobjectfunction ntqueryobject = NULL; callback ("ntqueryobject", & ntqueryobject); object_name_information initial_buffer; object_name_information * name = & initial_buffer; ulong size = Si Zeof (initial_buffer); // query the name information a first time to get the size of the name. ntstatus status = ntqueryobject (handle, objectnameinformation, name, size, & size); scoped_ptr name_ptr; If (size) {name = reinterpret_cast (New byte [size]); name_ptr.reset (name); // query the name information a second time to get the name of the // object referenced by the handle. status = ntqueryobject (H Andle, objectnameinformation, name, size, & size) ;}if (STATUS_SUCCESS! = Status) return false; Path-> assign (name-> objectname. buffer, name-> objectname. length/sizeof (name-> objectname. buffer [0]); Return true;} // converts a Win32 path to native (NT) type of path // http://stackoverflow.com/questions/4445108/how-can-i-convert-a-native-nt-pathname-into-a-win32-path-name//http://pdh11.blogspot.com/2009/05/pathcanonicalize-versus-what-it-says-on.html// resolves a Win32 path to an NT path using getpathfromhandle. the path must // exist. returs true if the translation was succesful. bool getntpathfromwin32path (const STD: wstring & Path, STD: wstring * nt_path) {handle file =: createfilew (path. c_str (), 0, file_cmd_read | file_cmd_write | file_cmd_delete, null, open_existing, empty, null); If (file = invalid_handle_value) return false; bool Rv = getpathfromhandle (file, nt_path);: closehandle (File); Return RV ;}

File Path: D:/project/Chrome/src/sandbox/src/win_utils.cc