Linux進程間通信-基於socket,過渡到網絡編程

寫在前面：小生純業餘選手，開此博僅僅是爲了積累，純當筆記來用。如有看官光臨小生博客，請不要相信我的代碼就是正確的。如果您發現了錯誤也懇請耽誤您一點時間，請您在下面指出來，不勝感激！

如果發現一些筆記的說法完全是錯誤的請建議我刪除！

有基於socket的進程通信方式，這種方式可以讓兩個不在同一臺主機上的進程進行通信

這裏的通信方式與前幾種有點不同，需要好好琢磨這種不同，方便以後學習網絡編程。

<span style="font-size:18px;"><span style="font-family:SimSun;font-size:18px;">#include<sys/socket.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<linux/un.h>
#include<unistd.h>

int main()
{
    char buf[256];
    
    int fd = socket(AF_UNIX,SOCK_DGRAM,0);
    if( fd == -1 )
    {
        printf("socket error:%m\n");
        exit(-1);
    }else
    {
        printf("socket complete\n");
    }
    
    struct sockaddr_un addr = {0};
    addr.sun_family = AF_UNIX;
    memcpy(addr.sun_path,"my.sock",strlen("my.sock"));
    
    int r = bind( fd,reinterpret_cast<struct sockaddr*>(&addr),sizeof(addr) );
    if( r == -1 )
    {
        printf("bind error:%m\n");
        exit(-1);
    }else
    {
        printf("bind complete\n");
    }
    
    while(1)
    {
        bzero(buf,sizeof(buf));
        r = read(fd,buf,sizeof(buf));
        buf[r] = '\0';
        printf("%s\n",buf);
    }
    
    close(fd);
    unlink("my.sock");
    
    return 0;
}
</span></span>

<span style="font-size:18px;"><span style="font-size:18px;">#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<linux/un.h>
#include<string.h>
#include<unistd.h>

int main()
{
    char buf[256];
    
    int fd = socket(AF_UNIX,SOCK_DGRAM,0);
    
    struct sockaddr_un addr = {0};
    addr.sun_family = AF_UNIX;
    memcpy(addr.sun_path,"my.sock",strlen("my.sock"));
    int r = connect(fd,reinterpret_cast<struct sockaddr*>(&addr),sizeof(addr));

    write(fd,"come from socketB!",strlen("come from socketB!"));
    
    close(fd);
    //unlink("my.sock");
    return 0;
}
</span></span>

下面一個程序給上面那個程序發送數據

以下兩段程序綁定的文件時一個網卡，實現不同主機間的進程的相互通信

#include<sys/socket.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>

int main()
{
    char buf[256];
    
    int fd = socket(AF_INET,SOCK_DGRAM,0);
    if(fd == -1 )
    {
        printf("socket error:%m\n");
        exit(-1);
    }else
    {
        printf("socket complete:%m\n");
    }
    
    struct sockaddr_in addr = {0};
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8888);
    addr.sin_addr.s_addr = inet_addr("192.168.64.128");
    
    int r = bind(fd,reinterpret_cast<struct sockaddr*>(&addr),sizeof(addr));
    if(r == -1)
    {
        printf("bind error%m\n");
        exit(-1);
    }else{
        printf("bind complete\n");
    }
    
    while(1)
    {
        bzero(buf,sizeof(buf));
        r = read(fd,buf,sizeof(buf));
        buf[r] = '\0';
        printf("%s\n",buf);
    }
    
    close(fd);
    unlink("my.sock");
    return 0;
}

#include<sys/socket.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>

int main()
{    
    int fd = socket(AF_INET,SOCK_DGRAM,0);
    
    if(fd == -1 )
    {
        printf("socket error:%m\n");
        exit(-1);
    }else{
        printf("socket complete:%m\n");
    }
    
    struct sockaddr_in addr = {0};
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8888);
    addr.sin_addr.s_addr = inet_addr("192.168.64.128");
    
    int r = connect(fd,reinterpret_cast<struct sockaddr*>(&addr),sizeof(addr));
    if(r == -1)
    {
        printf("bind error%m\n");
        exit(-1);
    }else{
        printf("bind complete\n");
    }
    
    write(fd,"come from ipB!",strlen("come from ipB!"));
    close(fd);
    return 0;
}

將以上兩段程序與開始兩段程序對比着看，總的來說編程的步驟是一樣的，主要是結構體struct sockaddr_un{}與struct sockaddr_in{}的無別和socket()中第一個參數的區別。這也說明了基於socket的進程間的通信模型可以很好的推廣到網絡編程。