#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <pthread.h>#include "server.h"#include "link.h"typedef struct threadargs{  int sock;  LList *list;}threadargs;int getuser(char *buf,char *username,LList *userlist);char iscmd(const char * message);int useratlist(LList *userlist,char *username);int findclientsock(LList *userlist,char *username);char *getsecond(char *message);char *getthird(char *message);void domessage(char *dest,char * userfrom,char *message);void accept_cli(threadargs *newargs);int main(int argc, char *argv[]){  int sctcp;  char hostname[80] = "";  struct sockaddr_in SC_link = { 0 };  int server_port=8000;  int childPid=0;  static LList userlist;  InitList(&userlist);  pthread_t id;  int ret;  printf("Server is starting\n");  sctcp=tcpSocket();	//client-server comunicate with tcp  Setsockopt(sctcp);		//set SO_REUSEADDR,SO_LINGER opt  GetHostName(hostname, sizeof(hostname));  CreateSockAddr(hostname,&SC_link,server_port);  Bind(sctcp, (struct sockaddr *) &SC_link,sizeof(SC_link));  Listen(sctcp);  printf("Server started successfully and it is ready now\n");  printf("Now entered listening mode\n");  for (;;)  {    struct sockaddr_in client_sockaddr = { 0 };    int cli_socket, cli_sock2,clientLength = sizeof(client_sockaddr);    (void) memset(&client_sockaddr, 0, sizeof(client_sockaddr));    cli_socket = Accept(sctcp,(struct sockaddr *) &client_sockaddr, &clientLength);    if (-1 == cli_socket)    {      perror("accept()");    }    threadargs newargs;    newargs.sock=cli_socket;    newargs.list=&userlist;    //      accept_cli(&newargs);    ret=pthread_create(&id,NULL,(void *)accept_cli,&newargs);    if(ret!=0)      perror("thread create error");  }  return EXIT_SUCCESS;}void accept_cli(threadargs *newargs){  LList *userlist=newargs->list;  int cli_socket=newargs->sock;  int cli_sock2;  int recvn;	//num of recv bytes  char buf[bufsize+1]="";  char buf2[bufsize+1]="";  char cmd;  client newcli;  client lastuser;	//the user which client talk to last time  bzero(&newcli,sizeof(client));  bzero(&lastuser,sizeof(client));  if(-1==Recv(cli_socket,buf))    pthread_exit(NULL);  printf("%s",buf);  if(-1==Send(cli_socket,"Server OCP v0.0.1\n"))    pthread_exit(NULL);  bzero(buf,bufsize);  if(-1==Recv(cli_socket,buf))    pthread_exit(NULL);  Rtrim(buf);  while(useratlist(userlist,buf)==0) //username has been used  {    if(-1==Send(cli_socket,":x"))      pthread_exit(NULL);    bzero(buf,bufsize);    if(-1==Recv(cli_socket,buf))      pthread_exit(NULL);    Rtrim(buf);  }  Send (cli_socket,"Longin Successfully\n");  strncpy(newcli.nick,buf,strlen(buf));  newcli.sock=cli_socket;  ListInsert(userlist,newcli);  while(1)  {    LNode *node=userlist->head->next; //use in :a    bzero(buf,bufsize);    if(Recv(cli_socket,buf)==-1)	//client offline    {      ListDelete(userlist,cli_socket);      pthread_exit(NULL);    }    if((cmd=iscmd(buf))==0)	//if message body contains only message(not have a command)    {      if(useratlist(userlist,lastuser.nick)==0)      {        cli_sock2=lastuser.sock;        domessage(buf2,newcli.nick,buf);        if(-1==Send(cli_sock2,buf2))          pthread_exit(NULL);      }      else      {        if(-1==Send(cli_socket,"The user you want to talk isn't online\n"))          pthread_exit(NULL);      }      continue;    }    switch(cmd)    {    case 'l':      bzero(buf,bufsize);      LNode *user=userlist->head->next;      while(user!=NULL)      {        strcat(buf,user->e.nick);        strcat(buf,"\n");        user=user->next;      }      if(-1==Send(cli_socket,buf))        pthread_exit(NULL);      break;    case 'u':	//client change user which will talk to      if(getuser(buf,lastuser.nick,userlist)!=-1)	//buf client's message //buf2 username      {cli_sock2=findclientsock(userlist,lastuser.nick);        lastuser.sock=cli_sock2;        if(getthird(buf)!=NULL)        {          domessage(buf2,newcli.nick,getthird(buf));          if(-1==Send(cli_sock2,buf2))            pthread_exit(NULL);        }      }      else      {        if(-1==Send(cli_socket,"You doesn't specify a user,or the user you want to talk to isn't online\n"))          pthread_exit(NULL);      }      break;    case 'q':	//client quit      if(-1==Send(cli_socket,buf))        pthread_exit(NULL);      ListDelete(userlist,cli_socket);      close(cli_socket);      pthread_exit(NULL);      break;    case 'a':	//client talk to all user      while(node!=NULL)      {        client user=node->e;        cli_sock2=user.sock;        if (cli_sock2!=cli_socket)	//don't send the message to your          {   if(getsecond(buf)!=NULL)	//if the message body only contains the :a string            domessage(buf2,newcli.nick,getsecond(buf));          if(-1==Send(cli_sock2,buf2))            pthread_exit(NULL);        }        node=node->next;      }      break;    default :      if(-1==Send(cli_socket,"Sever can't recognize your command\n"))        pthread_exit(NULL);    }  }}int getuser(char *buf,char *username,LList *userlist)	//if the user is online(int the userlist),set the username string,return 0,else return -1{  const char delimiters[] = " ";  char *token, *cp;  cp = strdup(buf);  token = strtok (cp, delimiters);  token = strtok (NULL, delimiters);	//token=username  if(token==NULL) return -1;  strncpy(username,token,namesize);  if(username[strlen(username)-1]='\n')    username[strlen(username)-1]=0;  return useratlist(userlist,username);}char iscmd(const char * message)	//get command{  char cmd;  if((cmd=message[0])!=':')    return 0;  return message[1];}int useratlist(LList *userlist,char *username){  LNode *node=userlist->head->next;  client user;  while(node!=NULL)  {    user=node->e;    if(strncmp(user.nick,username,strlen(username))==0)      return 0;    else node=node->next;  }  return -1;}int findclientsock(LList *userlist,char *username){  LNode *node=userlist->head->next;  client user;  while(node!=NULL)  {    user=node->e;    if(strncmp(user.nick,username,strlen(username))==0)      return user.sock;    else node=node->next;  }  return -1;}char *getsecond(char *message){  const char delimiters[] = " ";  char *token, *cp;  cp = strdup(message);  token = strtok (cp, delimiters);  token = strtok (NULL, delimiters);  return token;}char *getthird(char *message){  const char delimiters[] = " ";  char *token, *cp;  cp = strdup(message);  token = strtok (cp, delimiters);  token = strtok (NULL, delimiters);  token = strtok (NULL, delimiters);  return token;}void domessage(char *dest,char * userfrom,char *message){  strcpy(dest,"From ");  strcat(dest,userfrom);  strcat(dest,": ");  strcat(dest,message);}