linux-interprocess communication (quad): Domain sockets

1. Domain Sockets:

(1) can only be used for communication between different processes on the same device;

(2) efficiency is higher than network sockets. A domain socket is simply a copy of the data and does not go through the protocol stack;

(3) reliable, full duplex;

2. Domain Socket address structure:

struct Sockaddr_un {    /*af_unix*/    char sun_path[108/*  Pathname*/};

When we bind an address to a domain socket, the system creates a file of type S_ifsock with that pathname, tells the client name, does not open, and cannot communicate.

Do not automatically delete, need to delete the program after completion, if the file already exists, Bind failed;

3. Test the code:

Server.c

1#include <sys/types.h>2#include <sys/socket.h>3#include <sys/un.h>4#include <stdio.h>5#include <stdlib.h>6 7 #defineUn_path "/var/tmp/test_domain_socket"8 9 Ten intMainintargcChar*argv[]) One { A     intSOCKFD =-1; -     structsockaddr_un un; -     intLen =0; the  -     if(SOCKFD = socket (Af_unix, Sock_stream,0)) <0){ -Perror ("Create socket error\n"); -         Goto_error; +     } -  +memset (&un,0,sizeof(un)); Aun.sun_family =Af_unix; at strcpy (Un.sun_path, un_path); -  -Len =sizeof(un.sun_family) +sizeof(Un.sun_path); -  -     if(Bind (SOCKFD, (structSOCKADDR *) &un, Len) <0){ -Perror ("socket bind error\n"); in         Goto_error; -     } to  +     if(Listen (SOCKFD,5) <0){ -Perror ("Socket Listen error\n"); the     } *  $     intconn = Accept (SOCKFD, (structSOCKADDR *) &un, &len);Panax Notoginseng     if(Conn <0){ -Perror ("Accept error\n"); the         Goto_error; +     } A     Charbuf[ -] = {0}; the     intn = Read (conn, buf, the); +printf"recive-msg:%s", buf); - write (conn, buf, N); $ Close (conn); $  - Close (SOCKFD); - unlink (Un_path); the     return 0; - Wuyi _error: the     if(SOCKFD! =-1){ - Close (SOCKFD); Wu     } -  About     return-1; $}

Client.c

1#include <sys/types.h>2#include <sys/socket.h>3#include <sys/un.h>4#include <stdio.h>5#include <stdlib.h>6#include <unistd.h>7 8 #defineUn_path "/var/tmp/test_domain_socket"9 Ten  One intMainintargcChar*argv[]) A { -     intSOCKFD =-1; -     structsockaddr_un un; the     intLen =0; -  -     if(SOCKFD = socket (Af_unix, Sock_stream,0)) <0){ -Perror ("Create socket error\n"); +         Goto_error; -     } +  Amemset (&un,0,sizeof(un)); atun.sun_family =Af_unix; - strcpy (Un.sun_path, un_path); -  -Len =sizeof(un.sun_family) +sizeof(Un.sun_path); -  -     if(Connect (SOCKFD,structSOCKADDR *) &un, Len) <0){ inPerror ("Socket Connect error\n"); -         Goto_error; to     } +  -     Charbuf[ -] = {0}; the     intn = Read (Stdin_fileno, buf, the); * Write (SOCKFD, buf, n); $printf"send-msg:%s", buf);Panax NotoginsengRead (SOCKFD, buf, the); -buf[ -] =' /'; theprintf"recv-msg:%s", buf); +  A Close (SOCKFD); the     return 0; +  - _error: $     if(SOCKFD! =-1){ $ Close (SOCKFD); -     } -  the     return-1; -}

linux-interprocess communication (quad): Domain sockets