1. Linux 环境下验证下列程序。
/*
1、服务器等候客户连接请求,一旦连接成功则显示客户的地址,接着接收该客户的
名字并显示。然后接收来自该客户的信息(字符串) 。每当收到一个字符串,则显示
该字符串,并将字符串反转,再将反转的字符串发回客户端。之后,继续等待接收
该客户的信息直至该客户关闭连接。服务器具有同时处理多个客户的能力。
2、客户首先与相应服务器连接。接着接收用户输入的客户名字,再将名字发给服务
器。然后接收用户输入的字符串,再将字符串发送给服务器,接收服务器发回的信
息并显示。之后,继续等待用户输入直至用户输入 CTRL+D。当收到用户输入
CTRL+D后,客户关闭连接并退出。
*/
/* client.c */
#include <stdio.h>
#include <unistd.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> /* netbd.h is needed for struct hostent
=) */
#define PORT 1234 /* Open Port on Remote Host */
#define MAXDATASIZE 100 /* Max number of bytes of data */
void process(FILE *fp, int sockfd);
char* getMessage(char* sendline,int len, FILE* fp);
int main(int argc, char *argv[])
{
int fd; /* files descriptors */
struct hostent *he; /* structure that will get information
about remote host */
struct sockaddr_in server; /* server's address information */
if (argc !=2) {
printf("Usage: %s <IP Address>\n",argv[0]);
exit(1);
}
if ((he=gethostbyname(argv[1]))==NULL){ /* calls gethostbyname()
*/
printf("gethostbyname() error\n");
exit(1);
}
if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){ /* calls socket()
*/
printf("socket() error\n");
exit(1);
}
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT); /* htons() is needed again */
server.sin_addr = *((struct in_addr *)he->h_addr);
if(connect(fd, (struct sockaddr *)&server,sizeof(struct
sockaddr))==-1){ /* calls connect() */
printf("connect() error\n");
exit(1);
}
process(stdin,fd);
close(fd); /* close fd */
}
void process(FILE *fp, int sockfd)
{
char sendline[MAXDATASIZE], recvline[MAXDATASIZE];
int numbytes;
printf("Connected to server. \n");
/* send name to server */
printf("Input name : ");
if ( fgets(sendline, MAXDATASIZE, fp) == NULL) {
printf("\nExit.\n");
return;
}
send(sockfd, sendline, strlen(sendline),0);
/* send message to server */
while (getMessage(sendline, MAXDATASIZE, fp) != NULL) {
send(sockfd, sendline, strlen(sendline),0);
if ((numbytes = recv(sockfd, recvline, MAXDATASIZE,0)) == 0) {
printf("Server terminated.\n");
return;
}
recvline[numbytes]='\0';
printf("Server Message: %s\n",recvline); /* it prints server's
welcome message */
}
printf("\nExit.\n");
}
char* getMessage(char* sendline,int len, FILE* fp)
{
printf("Input string to server:");
return(fgets(sendline, MAXDATASIZE, fp));
}
/* server.c */
#include <stdio.h> /* These are the usual header files */
#include <strings.h> /* for bzero() */
#include <unistd.h> /* for close() */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#define PORT 1234 /* Port that will be opened */
#define BACKLOG 5 /* Number of allowed connections */
#define MAXDATASIZE 1000
void process_cli(int connectfd, struct sockaddr_in client);
/* function to be executed by the new thread */
void* start_routine(void* arg);
struct ARG {
int connfd;
struct sockaddr_in client;
};
main()
{
int listenfd, connectfd; /* socket descriptors */
pthread_t thread;
struct ARG *arg;
struct sockaddr_in server; /* server's address information */
struct sockaddr_in client; /* client's address information */
int sin_size;
/* Create TCP socket */
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
/* handle exception */
perror("Creating socket failed.");
exit(1);
}
int opt = SO_REUSEADDR;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt,
sizeof(opt));
bzero(&server,sizeof(server));
server.sin_family=AF_INET;
server.sin_port=htons(PORT);
server.sin_addr.s_addr = htonl (INADDR_ANY);
if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct
sockaddr)) == -1) {
/* handle exception */
perror("Bind error.");
exit(1);
}
if(listen(listenfd,BACKLOG) == -1){ /* calls listen() */
perror("listen() error\n");
exit(1);
}
sin_size=sizeof(struct sockaddr_in);
while(1)
{
/* Accept connection */
if ((connectfd = accept(listenfd,(struct sockaddr
*)&client,&sin_size))==-1) {
perror("accept() error\n");
exit(1);
}
/* Create thread*/
arg = (struct ARG *)malloc(sizeof(struct ARG));
arg->connfd = connectfd;
memcpy((void *)&arg->client, &client, sizeof(client));
if (pthread_create(&thread, NULL, start_routine, (void*)arg))
{
/* handle exception */
perror("Pthread_create() error");
exit(1);
}
}
close(listenfd); /* close listenfd */
}
void process_cli(int connectfd, struct sockaddr_in client)
{
int num,i;
char recvbuf[MAXDATASIZE], sendbuf[MAXDATASIZE],
cli_name[MAXDATASIZE];
printf("You got a connection from %s.
",inet_ntoa(client.sin_addr) );
/* Get client's name from client */
num = recv(connectfd, cli_name, MAXDATASIZE,0);
if (num == 0) {
close(connectfd);
printf("Client disconnected.\n");
return;
}
cli_name[num - 1] = '\0';
printf("Client's name is %s.\n",cli_name);
while (num = recv(connectfd, recvbuf, MAXDATASIZE,0)) {
recvbuf[num] = '\0';
printf("Received client( %s ) message: %s",cli_name, recvbuf);
for (i = 0; i < num - 1; i++) {
sendbuf[i] = recvbuf[num - i -2];
}
sendbuf[num - 1] = '\0';
send(connectfd,sendbuf,strlen(sendbuf),0);
}
close(connectfd); /* close connectfd */
}
void* start_routine(void* arg)
{
struct ARG *info;
info = (struct ARG *)arg;
/* handle client’s requirement */
process_cli(info->connfd, info->client);
free(arg);
pthread_exit(NULL);
}
//运行结果
//修改上述的服务器代码,使得能够完成如下的功能:客户机 A 和客户机B相互之间可以通过服务器传递文本信息,服务器则记录双方通信的日志,通过编译运行。
/* server.c */
#include <stdio.h> /* These are the usual header files */
#include <strings.h> /* for bzero() */
#include <unistd.h> /* for close() */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#define PORT 1234 /* Port that will be opened */
#define BACKLOG 5 /* Number of allowed connections */
#define MAXDATASIZE 1000
static int i=0;
void process_cli(int connectfd, struct sockaddr_in client);
/* function to be executed by the new thread */
void* start_routine(void* arg);
struct ARG {
int connfd;
struct sockaddr_in client;
};
main()
{
int listenfd, connectfd; /* socket descriptors */
pthread_t thread;
struct ARG *arg;
struct sockaddr_in server; /* server's address information */
struct sockaddr_in client; /* client's address information */
int sin_size;
/* Create TCP socket */
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
/* handle exception */
perror("Creating socket failed.");
exit(1);
}
int opt = SO_REUSEADDR;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt,
sizeof(opt));
bzero(&server,sizeof(server));
server.sin_family=AF_INET;
server.sin_port=htons(PORT);
server.sin_addr.s_addr = htonl (INADDR_ANY);
if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct
sockaddr)) == -1) {
/* handle exception */
perror("Bind error.");
exit(1);
}
if(listen(listenfd,BACKLOG) == -1){ /* calls listen() */
perror("listen() error\n");
exit(1);
}
sin_size=sizeof(struct sockaddr_in);
while(1)
{
/* Accept connection */
if ((connectfd = accept(listenfd,(struct sockaddr
*)&client,&sin_size))==-1) {
perror("accept() error\n");
exit(1);
}
/* Create thread*/
arg = (struct ARG *)malloc(sizeof(struct ARG));
arg->connfd = connectfd;
memcpy((void *)&arg->client, &client, sizeof(client));
if (pthread_create(&thread, NULL, start_routine, (void*)arg))
{
/* handle exception */
perror("Pthread_create() error");
exit(1);
}
}
close(listenfd); /* close listenfd */
}
void process_cli(int connectfd, struct sockaddr_in client)
{
FILE *readlog;
FILE *writelog;
int num;
char recvbuf[MAXDATASIZE], sendbuf[MAXDATASIZE],
cli_name[MAXDATASIZE];
printf("You got a connection from %s.",inet_ntoa(client.sin_addr) );
/* Get client's name from client */
num = recv(connectfd, cli_name, MAXDATASIZE,0);
if (num == 0) {
close(connectfd);
printf("Client disconnected.\n");
return;
}
cli_name[num - 1] = '\0';
printf("Client's name is %s.\n",cli_name);
while (num = recv(connectfd, recvbuf, MAXDATASIZE,0)) {
if(i!=0)
{
if((readlog=fopen("log.txt","a+"))==NULL)
{
fclose(readlog);
exit(0);
}
while((fgetc(readlog))!=EOF)
fgets(sendbuf,1024,readlog);
fclose(readlog);
}else
{
sprintf(sendbuf," ");
}
i++;
send(connectfd,sendbuf,strlen(sendbuf),0);
recvbuf[num] = '\0';
printf("Received client( %s ) message: %s",cli_name, recvbuf);
if((writelog=fopen("log.txt","a+"))==NULL)
{
fclose(writelog);
exit(0);
}
fputs(recvbuf,writelog);
fclose(writelog);
}
close(connectfd); /* close connectfd */
}
void* start_routine(void* arg)
{
struct ARG *info;
info = (struct ARG *)arg;
/* handle client’s requirement */
process_cli(info->connfd, info->client);
free(arg);
pthread_exit(NULL);
}
//clent.c
/* client.c */
#include <stdio.h>
#include <unistd.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> /* netbd.h is needed for struct hostent
=) */
#define PORT 1234 /* Open Port on Remote Host */
#define MAXDATASIZE 100 /* Max number of bytes of data */
void process(FILE *fp, int sockfd);
char* getMessage(char* sendline,int len, FILE* fp);
int main(int argc, char *argv[])
{
int fd; /* files descriptors */
struct hostent *he; /* structure that will get information
about remote host */
struct sockaddr_in server; /* server's address information */
if (argc !=2) {
printf("Usage: %s <IP Address>\n",argv[0]);
exit(1);
}
if ((he=gethostbyname(argv[1]))==NULL){ /* calls gethostbyname()
*/
printf("gethostbyname() error\n");
exit(1);
}
if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){ /* calls socket()
*/
printf("socket() error\n");
exit(1);
}
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT); /* htons() is needed again */
server.sin_addr = *((struct in_addr *)he->h_addr);
if(connect(fd, (struct sockaddr *)&server,sizeof(struct
sockaddr))==-1){ /* calls connect() */
printf("connect() error\n");
exit(1);
}
process(stdin,fd);
close(fd); /* close fd */
}
void process(FILE *fp, int sockfd)
{
char sendline[MAXDATASIZE], recvline[MAXDATASIZE];
int numbytes;
printf("Connected to server. \n");
/* send name to server */
printf("Input name : ");
if ( fgets(sendline, MAXDATASIZE, fp) == NULL) {
printf("\nExit.\n");
return;
}
send(sockfd, sendline, strlen(sendline),0);
/* send message to server */
while (getMessage(sendline, MAXDATASIZE, fp) != NULL) {
send(sockfd, sendline, strlen(sendline),0);
if ((numbytes = recv(sockfd, recvline, MAXDATASIZE,0)) == 0) {
printf("Server terminated.\n");
return;
}
recvline[numbytes]='\0';
printf("friend say: %s\n",recvline); /* it prints server's
welcome message */
}
printf("\nExit.\n");
}
char* getMessage(char* sendline,int len, FILE* fp)
{
printf("my say:");
return(fgets(sendline, MAXDATASIZE, fp));
}
//运行结果
