solaris DOOR类型文件

    今天在solaris上测试文件类型。 S_ISDIR(), S_ISCHR()等等。用了七个函数判断文件类型。 后来发现并没有发现DOOR这种文件类型。

man ls：

.......

D  the entry is a door.

........

它是door类型。 而且在<sys/stat.h>中可以查到 S_ISDOOR()函数。 

继续跟踪查door，在google的网上论坛上找到了DOORdescription。 

如下：

Well, the manual page for "door" in Solaris 2.5 says:

    DESCRIPTION

         This family of system calls provide a new flavor of
         interprocess communication between client and server
         processes. The doors mechanism is not yet available for public
         consumption because the interface is still evolving and will
         undergo a major rework in a future release of Solaris. In
         Solaris 2.5, doors are used as part of the implementation of
         the name service cache daemon, nscd(1M).

    WARNING

         Please do not attempt to reverse-engineer the interface and
         program to it. If you do, your program will almost certainly
         fail to run on future versions of Solaris, and may even be
         broken by a patch. This document does not constitute an API.
         Doors may not exist or may have a completely different set of
         semantics in a future release.

    NOTES

         This manual page is here solely for the benefit of anyone who
         noticed door_call() in truss(1) output and thought, "Gee, I
         wonder what that does..."

         Processes that appear to be "stuck" waiting in door_call(2)
         are probably waiting for nscd(1M) to reply to a name service
         lookup.

总的来说它提供了一种新的形式的接口，用于客户端和服务器的应用进程之间通信的文件。

具体使用方法，还得待查。