rpc

RPC是远程过程调用（Remote Procedure Call）的缩写形式。SAP系统RPC调用的原理其实很简单，有一些类似于三层构架的C/S系统，第三方的客户程序通过接口调用SAP内部的标准或自定义函数，获得函数返回的数据进行处理后显示或打印

Since the idea of RPC goes back to 1976 and the first business use was by Xerox in 1981, I’m not exactly sure what qualifies as a really old tutorial.

Here are a few resources you might find helpful.

• Power Programming with RPC (1992)
• Remote Procedure Calls | Linux Journal (Oct 01, 1997)
• Remote Procedure Calls (RPC) (1999)
• Remote Procedure Call Programming Guide (PDF link)
• rpc(3) - Linux man page

rpcgen

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$rpcgen --version
rpcgen (Ubuntu GLIBC 2.27-3ubuntu1) 2.27

rpcinfo

report RPC information

Q&A

Cannot register service: RPC: Unable to receive; errno = Connection refused

portmap是为RPC程序服务的。每一个RPC server程序启动的时候要向portmap程序注册。这样portmap程序就知道这些RPC server监听在哪个端口。 而RPC client在发起连接向portmap发起查询，知道了想要查询的RPC server的监听端口后再去连接server

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sudo apt install portmap rpcbind
sudo systemctl status portmap.service

示例

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$find /usr/include/ -name "*.x"
/usr/include/rpcsvc/key_prot.x
/usr/include/rpcsvc/bootparam_prot.x
/usr/include/rpcsvc/sm_inter.x
/usr/include/rpcsvc/klm_prot.x
...

结构体

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program YPPASSWDPROG {
        version YPPASSWDVERS {
                /*
                 * Update my passwd entry
                 */
                int
                YPPASSWDPROC_UPDATE(yppasswd) = 1;
        } = 1;
} = 100009;


struct passwd {
        string pw_name<>;       /* username */
        string pw_passwd<>;     /* encrypted password */
        int pw_uid;             /* user id */
        int pw_gid;             /* group id */
        string pw_gecos<>;      /* in real life name */
        string pw_dir<>;        /* home directory */
        string pw_shell<>;      /* default shell */
};

struct yppasswd {
        string oldpass<>;       /* unencrypted old password */
        passwd newpw;           /* new passwd entry */
};

https://unix.stackexchange.com/questions/344015/what-are-the-x-files-in-usr-include

函数指针

參考

• Remote Procedure Calls
• C/C++ RPC Tutorial for Linux [closed]
• Linux下C语言RPC（远程过程调用）编程实例
• rpcgen Programming Guide
• Writing Remote Procedural Calls (RPCs) in C
• Passing character pointers from client to server in RPCGen
• Writing RPC Applications with the rpcgen Protocol Compiler