Programming

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Listen(simpleSocket, 5);

signal(SIGCHLD, sigchld_handler);

/*****************************************************************/
while (1)
{
int tmpSock = 0;
int pid;
char buf[200] = "";
sendPack sp; /*struct traveling btw 3 programs*/
struct sockaddr_in clientName = { 0 };
int clientNameLength = sizeof(clientName);
int valUsr = 0, i = 0, status = 0;

/* wait here */
/*************************************************************/
simpleChildSocket = Accept(simpleSocket,
(struct sockaddr *)&clientName, &clientNameLength);
/*************************************************************/

if((pid = fork()) == 0)
{
/*if I close listen socket here, parent process cannot accept connection next time*/
close(simpleSocket);

returnStatus = Read(simpleChildSocket, &sp,
sizeof(sp));

if(sp.flag == 1)
{
/* printf("here we go: %s\n", sp.usrName); */
login(sp.usrName, simpleChildSocket, usrHead);

}
else if(sp.flag == 2)
{
if((tmpSock = judgeUser(usrHead, sp.usrName)))
{
status = 1;
Write(simpleChildSocket, &status, sizeof(int));
printf("Pass judgeUser.\n");
returnStatus = read(simpleChildSocket, &sp,
sizeof(sp));

if ( returnStatus > 0 ) {
printf("%d: %s", returnStatus, sp.usrName);
} else {
fprintf(stderr, "Return Status = %d \n", returnStatus);
}
while(sp.func != 4)
{
/*judge val of returnStatus inside func.*/
if(returnStatus > 0)
{
printf("Switch start..\n");
switch(sp.func)
{
case 1:
printf("Single send server.\n");
relaySingle(sp, usrHead, simpleChildSocket);
break;
case 2:
relayGroup(sp, usrHead, simpleChildSocket);
break;
case 3:
queryUsr(usrHead, simpleChildSocket);
break;
default :
break;
}

}
memset(&sp, '\0', sizeof(sp));
returnStatus = Read(simpleChildSocket, &sp,
sizeof(sp));
}
/*Delete quitting usrName.*/
sendQuit(usrHead, sp.usrName);
Write(tmpSock, &sp, sizeof(sp));
}
else
{
printf("You have not logged in yet.\n");
Write(simpleChildSocket, &status, sizeof(int));
}
}

/*If I use exit(0) or close child socket here, parent process cannot accept connection next time.*/
close(simpleChildSocket);
exit(0);
}

}

close(simpleSocket);
return 0;

}