server.c

一个简单的p2p共享文件的程序

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
////////structures and dates declare!////////////////
#define MSGMAX 100 
#define BUFMAX 104 //buffer=head+msg
#define LGIN 1
#define ERROR 2
#define LRES 3 
#define SHRE 4
#define SHOK 5
#define SRCH 6
#define SRES 7
#define QUIT 8
int end=0;
struct Message 
{
      int head;
      unsigned char content[MSGMAX];     
};
/////////functions/////////////////////////////
void sendERROR(int client_sockfd,char * alert)
{
	printf("Enter sendERROR\n");
	struct Message snd;
	unsigned char *buf2; //snd buffer!
	buf2=(unsigned char *)malloc(BUFMAX); //dynamic alloc mem!!!!so fucking!

	snd.head=ERROR;
	strcpy(snd.content,alert);
	printf("pop:%s\n",snd.content);
	memset(buf2,'\0', BUFMAX);
	buf2=(unsigned char *)&snd;
	printf("send %d bytes \n",write(client_sockfd, buf2, BUFMAX)); 
	end=1;
};
void dealwithSRCH(struct Message msg,int client_sockfd)
{
	printf("Enter dealwithSRCH\n");
	struct Message snd;
	unsigned char *buf2; //snd buffer!
	buf2=(unsigned char *)malloc(BUFMAX); //dynamic alloc mem!!!!so fucking!

	char *search;
	search=strtok(msg.content,"\n");
	int i;
	char filebuffer[1000];
	char *result;

	FILE *file;
	if((file=fopen("sharelist.txt","r+"))==NULL){
		printf("can not open file!\n");
		return;
	}
	//build buffer for sharelist.txt  
	memset(filebuffer,'\0',sizeof(filebuffer));
	fseek(file,0L,SEEK_END); //set to the END
	i=ftell(file);
	fseek(file,0L,SEEK_SET); //set to the begin
	i=fread(filebuffer,1,i,file);//read all !so hard way
	fclose(file);
	//filter the empty line!
//	strtok(filebuffer,"\n");
	//searching
	result=strtok(filebuffer,"#");
	while(result!=NULL){
		
		if(strncmp(result,search,strlen(result))==0 || strcmp("txt",search)==0){
			printf("find file\n");
			
			//build snd msg!
			memset(&snd,'\0',BUFMAX);
			memset(buf2,'\0', BUFMAX);
			snd.head=SRES;
			strcpy(snd.content,result);//get filename
			strcat(snd.content,"#");
			result=strtok(NULL,"\n"); //get rest
			strcat(snd.content,result);
			strcat(snd.content,"\n");
			result=strtok(NULL,"#");
		//	printf("1.snd=%s\n",snd.content);
			//send!
			buf2=(unsigned char *)&snd;
		//	printf("2.snd=%s\n",snd.content);
			printf("send %d bytes,content is %s \n",write(client_sockfd, buf2, BUFMAX),snd.content); 
		//	printf("3.snd=%s\n",snd.content);
		}else{
			strtok(NULL,"\n");
			result=strtok(NULL,"#"); //point next
		}//end if
	}//end while
	//snd eof
	memset(&snd,'\0',BUFMAX);
	memset(buf2,'\0', BUFMAX);
	snd.head=SRES;
	strcpy(snd.content,"\n");
	buf2=(unsigned char *)&snd;
	printf("2.snd=%s\n",snd.content);
	printf("send %d bytes\n",write(client_sockfd, buf2, BUFMAX)); 
};
void dealwithSHRE(struct Message msg,int client_sockfd,char * ip,char * user)
{
	printf("Enter dealwithSHRE\n");
	char *eachfile;
	char *port;
	char writetoshare[100];
	char *contentbuffer;
	FILE *file;

	struct Message snd;
	unsigned char *buf2; //snd buffer!
	buf2=(unsigned char *)malloc(BUFMAX); //dynamic alloc mem!!!!so fucking!

	int flag=0;
	
	//varify the format of file
	printf("all is : %s",msg.content);
	//filter the \n of msg.content! shit!
	contentbuffer=strtok(msg.content,"\n");
	port=strtok(contentbuffer,"#");
	eachfile=strtok(NULL,"#");
	while(eachfile!=NULL){
		//printf("file:%s\n",eachfile);
		printf("cmp:%d vs %d\n",strcspn(eachfile,".txt"),strlen(eachfile)-4);
		if(strcspn(eachfile,".txt")!=strlen(eachfile)-4){
			//got error format error!
			sendERROR(client_sockfd,"error format\n");
			return;
		}
		//save the share file 
		if (flag==0){
			strcpy(writetoshare,eachfile);
			flag=1;
		}else
			strcat(writetoshare,eachfile);
		strcat(writetoshare,"#");
		strcat(writetoshare,user);
		strcat(writetoshare,"#");
		strcat(writetoshare,ip);
		strcat(writetoshare,"#");
		strcat(writetoshare,port);
		strcat(writetoshare,"\n");
		//printf("now:%s!!!\n",writetoshare);
		eachfile=strtok(NULL,"#");
	}
	//save the share file information to sharelist.txt
	if((file=fopen("sharelist.txt","a+"))==NULL){
		printf("can not open file:sharelist.txt\n");
		return;
	}
	printf("write=%s",writetoshare);
	fwrite(writetoshare,1,strlen(writetoshare),file);//copy to file
	fclose(file);
	//respone 
	snd.head=SHOK;
	strcpy(snd.content,"\n");
	memset(buf2,'\0', BUFMAX);
	buf2=(unsigned char *)&snd;
	printf("send %d bytes \n",write(client_sockfd, buf2, BUFMAX)); 
};
void dealwithLGIN(struct Message msg,int client_sockfd,char * u)
{
	printf("Enter dealwithLGIN\n");
	char *username;
	username=(char *)malloc(20);
	char *password;//temp
	char realpwd[50];//password had been decode 
	char userlist[1000]; // buffer for userlist
	char usrpwd[50],*splits="#";//temp
	int i;//temp
	char *onematch;//temp	

	struct Message snd;
	unsigned char *buf2; //snd buffer!
	buf2=(unsigned char *)malloc(BUFMAX); //dynamic alloc mem!!!!so fucking!
	
	username=strtok(msg.content,"#"); //get username
	password=strtok(NULL,"\n");//get pwd
	//decrypt password
	printf("u:%s,p:%s\n",username,password);
	for(i=1;i<strlen(password);i++)
		realpwd[i-1]=password[i]+password[0]-'0';
	//check the identity form database(userlist.txt)
	FILE *file;
	if((file=fopen("userlist.txt","r+"))==NULL){
		printf("can not open file!\n");
		return;
	}
	//generate search string
	strcpy(usrpwd,username);		
	strcat(usrpwd,splits);
	strcat(usrpwd,realpwd);
	//build buffer for userlist.txt  
	memset(userlist,'\0',sizeof(userlist));
	fseek(file,0L,SEEK_END); //set to the END
	i=ftell(file);
	fseek(file,0L,SEEK_SET); //set to the begin
	i=fread(userlist,1,i,file);//read all !so hard way
	fclose(file);
	///////test///////////////////////////////////////////////////
	/*printf("userpwd:%s\n",usrpwd); //test
	printf("%s\n",userlist); //test
	printf("%d\n",i); //test*/
	//search and match
	onematch=strtok(userlist,"\n");
	while(onematch!=NULL){
		//printf("onematch:%s;usrpwd:%s\n",onematch,usrpwd);
		if(strncmp(onematch,usrpwd,strlen(onematch))==0){
			printf("find\n");
			snd.head=LRES;
			strcpy(snd.content,"log in succuss\n");
			memset(buf2,'\0', BUFMAX);
			buf2=(unsigned char *)&snd;
			printf("send %d bytes \n",write(client_sockfd, buf2, BUFMAX)); 
			strcpy(u,username);
			printf("in user:%s\n",username);
			return ;	
		}
		onematch=strtok(NULL,"\n");
	}
	//not find send error
	sendERROR(client_sockfd,"invalid log in");	
	return ;
};
int main()
{
	int server_sockfd, client_sockfd;
	struct sockaddr_in server_addr, client_addr;
	socklen_t client_len;//size of client_addr
	unsigned char buf[BUFMAX];//rcv buffer

    	struct Message msg;//the package rcv
	pid_t pid;

	char username[20];//log in sucuss username
	

	client_len = sizeof(client_addr);
	//set the server addr
	bzero((char *)&server_addr, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//get my ip add
	server_addr.sin_port = htons(8092);
	//create socket  SOCK_STREAM for TCP
	if ((server_sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
		perror("create server socket error");
	}
	// bind socket with my ip 
	if (bind(server_sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
		perror("bind server socket error");
	}
	//listen and create connection,at most 5 connections
	if (listen(server_sockfd, 5) < 0) {
		perror("listen server socket error");
	}
	
	printf("<BEGIN>\n");

	for (;;) {
		printf("Waiting for connect...\n");
		//get client sock
		client_len=sizeof(client_addr);
		client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_addr, &client_len);
		////////////////fork////////////////////
		pid=fork();
		if(pid>0){}
		else if(pid==0){
		/////////////end fork//////////////////////
		printf("client ip:%s,sockfd:%d\n",inet_ntoa(client_addr.sin_addr.s_addr),client_sockfd);

		while(1){
			//read & write
        		memset(&msg,'\0', sizeof(&msg));
			memset(buf,'\0', sizeof(buf));
			//so important!!!!! must use the unsigned buffer
			read(client_sockfd, buf, sizeof(buf));
			msg=*(struct Message *)buf;
            		//	printf("recive request %d,%s\n", msg.head,msg.content); //test 
              		if(msg.head==LGIN){
				memset(&username,'\0',20);
				dealwithLGIN(msg,client_sockfd,&username);
				//printf("name:%s\n",username);
				break;
			}
		}//end while
		if(username[0]!='\0'){//log in sucuss
			while(1){
				//read & write
        			memset(&msg,'\0', sizeof(&msg));
				memset(buf,'\0', sizeof(buf));
				//so important!!!!! must use the unsigned buffer
				read(client_sockfd, buf, sizeof(buf));
				msg=*(struct Message *)buf;
				if(msg.head==SHRE){//deal with share file
					//printf("begin share\n");
					dealwithSHRE(msg,client_sockfd,inet_ntoa(client_addr.sin_addr.s_addr),username);

             			}else if (msg.head==SRCH){
					dealwithSRCH(msg,client_sockfd);
				}else if(msg.head==QUIT){
					printf("byebye:%s\n",username);
					break;
				}
			}//end while
		}
		close(client_sockfd); 
		/////////////////////////fork//////////////
		}else{ perror("fork error");}
		//return 0;          
	}
    
    return 0;
}