[fm setAttributes:@{NSFilePosixPermissions : [NSNumber numberWithShort:0666]}
ofItemAtPath:[NSString stringWithFormat:@"%@-shm",_path]
error:nil];
[fm setAttributes:@{NSFilePosixPermissions : [NSNumber numberWithShort:0666]}
ofItemAtPath:[NSString stringWithFormat:@"%@-shm",_path]
error:nil];