读取沙盒外的防火墙状态信息 默认是读取该路径下的文件Library/Preferences/com.apple.alf.plist中的globalstate字段的值 ，0–>off, 1–>ON
在沙盒内读取不了

NSDictionary* dictionary = [NSDictionary dictionaryWithContentsOfFile:@"/Library/Preferences/com.apple.alf.plist"];
       int status = [[dictionary valueForKey:@"globalstate"] intValue];
      if (status==0) {
          NSLog(@"close");
      }else{
           NSLog(@"open");
      }