循序渐进学unix——上机记录（七）,socket

本次的主题是基本网络编程：socket，涉及到的概念比较多，就不详细展开了。从编程角度简单的说，为了在客户端和服务器之间建立一个连接，服务器端需要依次调用这些函数：

1. socket，获得一个socket
2. bind，将获得的socket绑定到指定的地址和端口
3. listen，让此socket进入等待状态，等待客户端的连接
4. accept，当建立起与客户端之间的连接时，此函数返回代表此连接的socket。即类似于文件描述符，我们可以把客户端看作文件，向网络上进行读写操作，从而完成通信过程。

客户端需要调用的函数：

1. socket
2. connect，向指定地址的服务器的指定端口发起连接

服务器和客户端都需用到的通信函数：

1. send
2. recv

详细信息和函数方法等就不赘述了，请参见man 文档。

下面来看几道练习。

1. 从客户端把用户输入的信息发送到服务器，直到用户输入“over”。这是一道基础题，直接上代码了。

server：

#include <arpa/inet.h>#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <string.h>#include <unistd.h>int main(int argc, char *argv[]){int numPort, lenMsg, i;int sockServ, sockClient;struct sockaddr_in adrServ, adrClient;char message[256];char * overMsg = "over";int adrSize = sizeof(adrClient);int yes = 1;if(argc < 2){printf("syntaxe : %s numPort\n", argv[0]);return -1;}//set local addr and portnumPort = atoi(argv[1]);adrServ.sin_addr.s_addr = INADDR_ANY;adrServ.sin_family = AF_INET;adrServ.sin_port = htons(numPort);bzero(&(adrServ.sin_zero), 8) ;//Get a socketif((sockServ = socket(PF_INET, SOCK_STREAM, 0)) == -1) { perror("sockServet"); return -1; }//We can set some param here.// paramètrage de la socket pour réutiliser le N° ce port sans délaiif(setsockopt(sockServ, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) { perror("setsockopt"); return -1; }// bindif(bind(sockServ, (struct sockaddr *)(&adrServ), sizeof(adrServ)) == -1) { perror("bind"); return -1; }// place la socket en écouteif(listen(sockServ, 1) == -1) { perror("listen"); return -1; }// wait for a connection from a clientif((sockClient = accept(sockServ, (struct sockaddr *)(&adrClient), &adrSize)) == -1) { perror("accept"); return -1; }printf("New socket client : %s\n", inet_ntoa(adrClient.sin_addr));do{// Read a msg from clientif((lenMsg = recv(sockClient, message, 256, 0)) == -1){ perror("recv"); return -1; }message[lenMsg] = '\0';printf("New msg received : %s\n", message);//printf("New msg received : %s, %d\n", message, strcmp(message, overMsg));}while(strcmp(message, overMsg) != 0);// fermeture de la connexionclose(sockServ);return 0;}

client：

#include<stdio.h>#include<stdlib.h>#include<netinet/in.h>#include<sys/types.h>#include<unistd.h>#include<sys/socket.h>#include<string.h>void main(int argc, char* argv[]){if(argc < 3){printf("Syntax:%s server_addr <portNum>\n", argv[0]);exit(0);}int fdSock;//get a socketif( (fdSock=socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket"); exit(1);}//config the address of the server to connectstruct sockaddr_in addrServer;addrServer.sin_family = AF_INET;//Address familyinet_pton(AF_INET, argv[1], &(addrServer.sin_addr));//Convert the addr from "presentation" to "numeric"addrServer.sin_port=htons(atoi(argv[2]));//set the port number//Connect to serverif( connect( fdSock, (struct sockaddr *)(&addrServer), sizeof(addrServer))== -1){perror("connect"); exit(1);}char buf[1024];gets(buf);//get a msg from terminalwhile(buf[0] != '\0'){printf("Gets gets : %s\n", buf);//Send the msg to server. See also "sendto" and "sendmsg"if( send(fdSock, buf, strlen(buf), 0) == -1){perror("Send"); exit(1);}if(strcmp(buf, "over") == 0){printf("Exit...\n");close(fdSock);exit(0);}gets(buf);}}

运行结果：

client：

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./client12 127.0.0.1 9999helloGets gets : hellobyebyeGets gets : byebyeoverGets gets : overExit...administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ 

server：administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./server12 9999New socket client : 127.0.0.1New msg received : helloNew msg received : byebyeNew msg received : overadministrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ 

2. 这次结合上exec，从客户端发送命令到服务器，服务器在本地执行命令。

server：

#include <arpa/inet.h>#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <string.h>#include <unistd.h>#define MAX_NUM_ARG 10void exeCmd(char * cmd);int main(int argc, char *argv[]){int numPort, lenMsg, i;int sockServ, sockClient;struct sockaddr_in adrServ, adrClient;char message[256];char * overMsg = "over";int adrSize = sizeof(adrClient);int yes = 1;if(argc < 2){printf("syntaxe : %s numPort\n", argv[0]);return -1;}//set local addr and portnumPort = atoi(argv[1]);adrServ.sin_addr.s_addr = INADDR_ANY;adrServ.sin_family = AF_INET;adrServ.sin_port = htons(numPort);bzero(&(adrServ.sin_zero), 8) ;//Get a socketif((sockServ = socket(PF_INET, SOCK_STREAM, 0)) == -1) { perror("sockServet"); return -1; }//We can set some param here.// paramètrage de la socket pour réutiliser le N° ce port sans délaiif(setsockopt(sockServ, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) { perror("setsockopt"); return -1; }// bindif(bind(sockServ, (struct sockaddr *)(&adrServ), sizeof(adrServ)) == -1) { perror("bind"); return -1; }// place la socket en écouteif(listen(sockServ, 1) == -1) { perror("listen"); return -1; }// wait for a connection from a clientif((sockClient = accept(sockServ, (struct sockaddr *)(&adrClient), &adrSize)) == -1) { perror("accept"); return -1; }printf("New socket client : %s\n", inet_ntoa(adrClient.sin_addr));do{// Read a cmd from clientif((lenMsg = recv(sockClient, message, 256, 0)) == -1){ perror("recv"); return -1; }message[lenMsg] = '\0';printf("\nNew cmd received : %s, result:\n", message);exeCmd(message);//printf("New msg received : %s, %d\n", message, strcmp(message, overMsg));}while(strcmp(message, overMsg) != 0);// fermeture de la connexionclose(sockServ);return 0;}void exeCmd(char * cmd){if(fork()==0){char *argv[MAX_NUM_ARG] = {NULL};int i;char *arg;for(i=0; i<MAX_NUM_ARG; i++){if(i>0) cmd = NULL;arg = strtok(cmd, " ");if(arg != NULL){//put this arg into argv[]argv[i] = calloc( sizeof(char), strlen(arg+1)) ;strcpy(argv[i], arg);}else{//execute this cmdexecvp(argv[0], argv);exit(0);}}exit(0);}}

client：

#include<stdio.h>#include<stdlib.h>#include<netinet/in.h>#include<sys/types.h>#include<unistd.h>#include<sys/socket.h>#include<string.h>void main(int argc, char* argv[]){if(argc < 3){printf("Syntax:%s server_addr <portNum>\n", argv[0]);exit(0);}int fdSock;//get a socketif( (fdSock=socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket"); exit(1);}//config the address of the server to connectstruct sockaddr_in addrServer;addrServer.sin_family = AF_INET;//Address familyinet_pton(AF_INET, argv[1], &(addrServer.sin_addr));//Convert the addr from "presentation" to "numeric"addrServer.sin_port=htons(atoi(argv[2]));//set the port number//Connect to serverif( connect( fdSock, (struct sockaddr *)(&addrServer), sizeof(addrServer))== -1){perror("connect"); exit(1);}char buf[1024];printf("\nexcute_cmd_in_distance$");gets(buf);//get a cmd from terminalwhile(buf[0] != '\0'){//printf("Gets gets : %s\n", buf);//Send the msg to server. See also "sendto" and "sendmsg"if( send(fdSock, buf, strlen(buf), 0) == -1){perror("Send"); exit(1);}if(strcmp(buf, "over") == 0){printf("Exit...\n");close(fdSock);exit(0);}printf("\nexcute_cmd_in_distance$");gets(buf);}}

运行结果：

client：

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./client3 127.0.0.1 9999excute_cmd_in_distance$lsexcute_cmd_in_distance$ls -lexcute_cmd_in_distance$pwdexcute_cmd_in_distance$overExit...administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ 

server：

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./server3 9999New socket client : 127.0.0.1New cmd received : ls, result:12_client.c  3_client.c  client   client12  in.h      server3    td6-1_serveur-modif.c  types.h12_server.c  3_server.c  client1  client3   server12  socket.h    td6.pdfNew cmd received : ls -l, result:total 152-rw-r--r-- 1 administrateur administrateur  1171 déc.  26 12:39 12_client.c-rw-r--r-- 1 administrateur administrateur  1842 déc.  26 12:36 12_server.c-rw-r--r-- 1 administrateur administrateur  1250 déc.  26 13:28 3_client.c-rw-r--r-- 1 administrateur administrateur  2323 déc.  26 13:28 3_server.c-rw-r--r-- 1 administrateur administrateur  7563 déc.   5 15:17 client-rwxrwxr-x 1 administrateur administrateur  7549 déc.  26 11:47 client1-rwxrwxr-x 1 administrateur administrateur  7623 déc.  26 12:31 client12-rwxrwxr-x 1 administrateur administrateur  7622 déc.  26 13:28 client3-rw-r--r-- 1 administrateur administrateur 18637 janv. 22  2011 in.h-rwxrwxr-x 1 administrateur administrateur  7668 déc.  26 12:36 server12-rwxrwxr-x 1 administrateur administrateur  7914 déc.  26 13:28 server3-rw-r--r-- 1 administrateur administrateur  9597 janv. 22  2011 socket.h-rw-r--r-- 1 administrateur administrateur  1953 déc.  26 11:46 td6-1_serveur-modif.c-rw-r--r-- 1 administrateur administrateur 44356 nov.  30 15:39 td6.pdf-rw-r--r-- 1 administrateur administrateur  6838 janv. 22  2011 types.hNew cmd received : pwd, result:/home/administrateur/Bureau/POLYTECH/unix/TD UNIX2012/td6New cmd received : over, result:administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ 

3. 理解”一切皆文件“的概念。将server的标准输入输出重定向到client，即从client读取命令字符串，并将执行结果返回给client输出。到这里不难发现我们所要做的有点像个远程终端。

并无特殊，加上重定向（在执行命令的子进程中）即可。

server：

#include <arpa/inet.h>#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <string.h>#include <unistd.h>#define MAX_NUM_ARG 10void exeCmd(int sockClient, char * cmd){if(fork()==0){//Set redirectiondup2(sockClient, 0);dup2(sockClient, 1);close(sockClient);char *argv[MAX_NUM_ARG] = {NULL};int i;char *arg;for(i=0; i<MAX_NUM_ARG; i++){if(i>0) cmd = NULL;arg = strtok(cmd, " ");if(arg != NULL){//put this arg into argv[]//argv[i] = calloc( sizeof(char), strlen(arg+1)) ;//strcpy(argv[i], arg);argv[i] = arg;//We can also simply do like this.fprintf(stderr, "cmd[%d] = %s\n",i,arg);}else{//execute this cmdexecvp(argv[0], argv);exit(0);}}exit(0);}}int main(int argc, char *argv[]){int numPort, lenMsg, i;int sockServ, sockClient;struct sockaddr_in adrServ, adrClient;char message[256];char * overMsg = "over";int adrSize = sizeof(adrClient);int yes = 1;if(argc < 2){printf("syntaxe : %s numPort\n", argv[0]);return -1;}//set local addr and portnumPort = atoi(argv[1]);adrServ.sin_addr.s_addr = INADDR_ANY;adrServ.sin_family = AF_INET;adrServ.sin_port = htons(numPort);bzero(&(adrServ.sin_zero), 8) ;//Get a socketif((sockServ = socket(PF_INET, SOCK_STREAM, 0)) == -1) { perror("sockServet"); return -1; }//We can set some param here.// paramètrage de la socket pour réutiliser le N° ce port sans délaiif(setsockopt(sockServ, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) { perror("setsockopt"); return -1; }// bindif(bind(sockServ, (struct sockaddr *)(&adrServ), sizeof(adrServ)) == -1) { perror("bind"); return -1; }// place la socket en écouteif(listen(sockServ, 1) == -1) { perror("listen"); return -1; }// wait for a connection from a clientif((sockClient = accept(sockServ, (struct sockaddr *)(&adrClient), &adrSize)) == -1) { perror("accept"); return -1; }printf("New socket client : %s\n", inet_ntoa(adrClient.sin_addr));do{// Read a cmd from client//fgets(stdin, message);//fscanf(sockClient,"%s",message);if((lenMsg = recv(sockClient, message, 256, 0)) == -1){ perror("recv"); return -1; }else if (lenMsg == 0){close(sockClient);return 0;}message[lenMsg] = '\0';printf("New cmd received : %s\n", message);exeCmd(sockClient, message);//fflush(sockClient);//printf("New msg received : %s, %d\n", message, strcmp(message, overMsg));}while(strcmp(message, overMsg) != 0);// fermeture de la connexionclose(sockClient);return 0;}

server运行结果：

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./server4 9999New socket client : 127.0.0.1New cmd received : lscmd[0] = lsNew cmd received : pwdcmd[0] = pwdNew cmd received : datecmd[0] = dateNew cmd received : ls -lcmd[0] = lscmd[1] = -lNew cmd received : overadministrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ cmd[0] = over

client：

#include<stdio.h>#include<stdlib.h>#include<netinet/in.h>#include<sys/types.h>#include<unistd.h>#include<sys/socket.h>#include<string.h>void main(int argc, char* argv[]){if(argc < 3){printf("Syntax:%s server_addr <portNum>\n", argv[0]);exit(0);}int fdSock, res;//get a socketif( (fdSock=socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket"); exit(1);}//config the address of the server to connectstruct sockaddr_in addrServer;addrServer.sin_family = AF_INET;//Address familyinet_pton(AF_INET, argv[1], &(addrServer.sin_addr));//Convert the addr from "presentation" to "numeric"addrServer.sin_port=htons(atoi(argv[2]));//set the port number//Connect to serverif( connect( fdSock, (struct sockaddr *)(&addrServer), sizeof(addrServer))== -1){perror("connect"); exit(1);}char buf[1024];printf("\nexcute_cmd_in_distance$");gets(buf);//get a cmd from terminalwhile(buf[0] != '\0'){//printf("Gets gets : %s\n", buf);//Send the msg to server. See also "sendto" and "sendmsg"if( send(fdSock, buf, strlen(buf), 0) == -1){perror("Send"); exit(1);}if(strcmp(buf, "over") == 0){printf("Exit...\n");close(fdSock);exit(0);}if( (res = recv(fdSock, buf, 1024, 0)) == -1){perror("recv"); exit(1);}else if(res == 0) {close(fdSock); exit(0);}else{buf[res] = '\0';printf("\n%s",buf);}printf("\nexcute_cmd_in_distance$");gets(buf);}}

client运行结果：

/home/administrateur/Bureau/POLYTECH/unix/TD UNIX2012/td6excute_cmd_in_distance$datemercredi 26 décembre 2012, 17:10:46 (UTC+0100)excute_cmd_in_distance$ls -ltotal 88-rw-r--r-- 1 administrateur administrateur  1171 déc.  26 12:39 12_client.c-rw-r--r-- 1 administrateur administrateur  1842 déc.  26 12:36 12_server.c-rw-r--r-- 1 administrateur administrateur  1250 déc.  26 13:28 3_client.c-rw-r--r-- 1 administrateur administrateur  2323 déc.  26 13:28 3_server.c-rw-r--r-- 1 administrateur administrateur  1433 déc.  26 17:10 4_client.c-rw-r--r-- 1 administrateur administrateur  2626 déc.  26 17:06 4_server.c-rwxrwxr-x 1 administrateur administrateur  7658 déc.  26 17:10 client4drwxrwxr-x 2 administrateur administrateur  4096 déc.  26 14:54 doc-rwxrwxr-x 1 administrateur administrateur  7947 déc.  26 17:10 server4-rw-r--r-- 1 administrateur administrateur 44356 nov.  30 15:39 td6.pdfexcute_cmd_in_distance$overExit...administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ 

5. 在第4题的基础上，我们考虑I/O多路复用。试想，当client发送完命令，并且正在等待执行结果的时候，用户又在终端输入了一条命令。由于程序被recv阻塞，用户输入的命令并不会被处理。有没有一种方法可以监听所有的io操作，并在任何一个操作结束阻塞的时候通知我们呢？没错，我们在谈select和poll函数。下面的实现使用了poll函数，请注意看它是如何同时监听所有io并在任何一个io操作准备就绪时返回的。

client：

#include<stdio.h>#include<stdlib.h>#include<netinet/in.h>#include<sys/types.h>#include<unistd.h>#include<sys/socket.h>#include<string.h>#include<poll.h>void main(int argc, char* argv[]){if(argc < 3){printf("Syntax:%s server_addr <portNum>\n", argv[0]);exit(0);}int fdSock, res, nready;//get a socketif( (fdSock=socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket"); exit(1);}//config the address of the server to connectstruct sockaddr_in addrServer;addrServer.sin_family = AF_INET;//Address familyinet_pton(AF_INET, argv[1], &(addrServer.sin_addr));//Convert the addr from "presentation" to "numeric"addrServer.sin_port=htons(atoi(argv[2]));//set the port number//Connect to serverif( connect( fdSock, (struct sockaddr *)(&addrServer), sizeof(addrServer))== -1){perror("connect"); exit(1);}char buf[1024];printf("\nexcute_cmd_in_distance$");//gets(buf);//get a cmd from terminal//POLL added herestruct pollfd pfds[2];bzero(pfds, sizeof(pfds[0]));bzero(pfds+1, sizeof(pfds[0]));pfds[0].fd = 0;pfds[0].events = POLLRDNORM;//The event waited.(Normal read)pfds[1].fd = fdSock;pfds[1].events = POLLRDNORM;while(buf[0] != '\0'){printf("\nexcute_cmd_in_distance$");nready = poll(pfds, 2, -1);//nready is the number of ready fdsif(pfds[0].revents & POLLRDNORM){//deal with user input, send cmd to servergets(buf);if( send(fdSock, buf, strlen(buf), 0) == -1){perror("Send"); exit(1);}if(strcmp(buf, "over") == 0){printf("Exit...\n");close(fdSock);exit(0);}pfds[0].revents = 0;nready --;if(nready == 0)continue;}if(pfds[1].revents & POLLRDNORM ){//deal with socket, display the result of the last cmdpfds[1].revents = 0;if( (res = recv(fdSock, buf, 1024, 0)) == -1){perror("recv"); exit(1);}else if(res == 0) {close(fdSock); exit(0);}else{buf[res] = '\0';printf("\n%s",buf);}}}}

server：代码无太大变化，除了exeCmd函数。现在我们使用”bash“命令来执行其它命令。

#include <arpa/inet.h>#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <string.h>#include <unistd.h>#define MAX_NUM_ARG 10void exeCmd(int sockClient, char * cmd){if(fork()==0){//Set redirectiondup2(sockClient, 0);dup2(sockClient, 1);close(sockClient);execlp("bash", "bash", "-c", cmd, NULL);exit(0);}}int main(int argc, char *argv[]){int numPort, lenMsg, i;int sockServ, sockClient;struct sockaddr_in adrServ, adrClient;char message[256];char * overMsg = "over";int adrSize = sizeof(adrClient);int yes = 1;if(argc < 2){printf("syntaxe : %s numPort\n", argv[0]);return -1;}//set local addr and portnumPort = atoi(argv[1]);adrServ.sin_addr.s_addr = INADDR_ANY;adrServ.sin_family = AF_INET;adrServ.sin_port = htons(numPort);bzero(&(adrServ.sin_zero), 8) ;//Get a socketif((sockServ = socket(PF_INET, SOCK_STREAM, 0)) == -1) { perror("sockServet"); return -1; }//We can set some param here.// paramètrage de la socket pour réutiliser le N° ce port sans délaiif(setsockopt(sockServ, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) { perror("setsockopt"); return -1; }// bindif(bind(sockServ, (struct sockaddr *)(&adrServ), sizeof(adrServ)) == -1) { perror("bind"); return -1; }// place la socket en écouteif(listen(sockServ, 1) == -1) { perror("listen"); return -1; }// wait for a connection from a clientif((sockClient = accept(sockServ, (struct sockaddr *)(&adrClient), &adrSize)) == -1) { perror("accept"); return -1; }printf("New socket client : %s\n", inet_ntoa(adrClient.sin_addr));do{if((lenMsg = recv(sockClient, message, 256, 0)) == -1){ perror("recv"); return -1; }else if (lenMsg == 0){close(sockClient);return 0;}message[lenMsg] = '\0';printf("New cmd received : %s\n", message);exeCmd(sockClient, message);}while(strcmp(message, overMsg) != 0);// fermeture de la connexionclose(sockClient);return 0;}

运行结果：

client：每条命令下显示的结果其实是在server端执行的。你发现什么变化没有？当我们执行find / -name "socket.h" 这条耗时的命令后，server端并不能马上返回结果，而我们仍可以马上执行下一条命令：date，并且我们先得到了date的结果，之后才是find命令的搜索结果。

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./4_client 127.0.0.1 9999lsexcute_cmd_in_distance$12_client.c12_server.c3_client.c3_server.c44_client4_client.c4_poll_client.c4_poll_client.c~4_poll_server.c4_poll_server.c~4_server.c4_server.c~client4clientPolldocserver4td6.pdfsudo find / -name "socket.h"excute_cmd_in_distance$datemercredi 26 décembre 2012, 17:53:30 (UTC+0100)excute_cmd_in_distance$/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/alpha/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/arm/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/avr32/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/blackfin/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/cris/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/frv/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/h8300/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/ia64/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/m32r/include/asm/socket.h/media/DONNEES/Polytech/Tutorial/Linux/linux-2.6.33.20/linux-2.6.33.20/arch/m68k/include/asm/socket.hexcute_cmd_in_distance$

server：

administrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./4syntaxe : ./4 numPortadministrateur@ordicentre:~/Bureau/POLYTECH/unix/TD UNIX2012/td6$ ./4 9999New socket client : 127.0.0.1New cmd received : lsNew cmd received : sudo find / -name "socket.h"[sudo] password for administrateur: New cmd received : date

可以看出server先后收到的所有命令。另外，由于重定向是在子进程中做得，所以要求输入密码的那行并没有发送给客户端而是在本地显示了。