int shmdt(const void *shmaddr){
pte_t *pte;
uint numOfPages;
pte = walkpgdir(proc->pgdir, (char*)shmaddr, 0);
acquire(&shmtable.lock);
int shmid = find_key(shmaddr);
shmtable.shmarray[shmid].linkcounter--;
numOfPages = shmtable.shmarray[shmid].pages_amount;
void *shmaddr2 = (void*)shmaddr;
for(; shmaddr2 < shmaddr + numOfPages*PGSIZE; shmaddr2 += PGSIZE)
{
pte = walkpgdir(proc->pgdir, (char*)shmaddr2, 0);
if(!pte)
shmaddr2 += (NPTENTRIES - 1) * PGSIZE;
*pte = 0;
}
if(!shmtable.shmarray[shmid].linkcounter){
shmtable.shmarray[shmid].shmstate = UNLINKED;
cprintf("freeing all the memory\n");
shmdel(shmid);
}
release(&shmtable.lock);
return 0;
}
void sig_term ( int sno )
{
printf ( "Removing Public Shared memory\n" ) ;
semdel ( p_semid ) ;
shmdel ( p_shmid ) ;
delc__semshm ( ) ;
exit ( errno ) ;
}
void delc__semshm( )
{
Position Pos, TmpPos ;
Pos = L_Client->Next ;
while ( Pos != NULL ) {
semdel ( Pos->Element->c_semid ) ;
shmdel ( Pos->Element->c_shmid ) ;
Pos = Pos->Next ;
}
DeleteList ( L_Client ) ;
}
main ( int argc, char **argv)
{
struct sockaddr_in sa;
struct sockaddr_in caller;
int ssd, csd, length, flag = 1 ;
char cnt_name[ 20 ] ;
int i, n, key, savesig ;
pid_t pid, loop_pid ;
struct client_ds *c_data ;
struct sigaction usr2act ;
sigset_t usr2mask, savemask, zeromask ;
if ( argc != 2 )
err_quit ( "Usage: %s <port>", argv[0] ) ;
if ( signal ( SIGUSR1, SIG_IGN ) == SIG_ERR )
err_sys ( "signal error" ) ;
if ( signal ( SIGINT, sig_term ) == SIG_ERR )
err_sys ( "signal error" ) ;
usr2act.sa_handler = sigusr2 ;
usr2act.sa_flags = SA_NOMASK ;
if ( sigaction ( SIGUSR2, &usr2act, NULL ) == -1 )
err_sys ( "sigaction error" ) ;
sigemptyset ( &zeromask ) ;
sigemptyset ( &usr2mask ) ;
sigaddset ( &usr2mask, SIGUSR2 ) ;
atexit ( end_func ) ;
key = p_key = atoi(argv[1]) ;
sa.sin_family= AF_INET;
sa.sin_addr.s_addr = INADDR_ANY;
sa.sin_port= htons((u_short)atoi(argv[1])) ;
if ((ssd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
err_sys ("socket error");
if (bind(ssd, (struct sockaddr *)&sa, sizeof sa) < 0)
err_sys ("bind error");
if ( ( p_semid = semget ( p_key, 1, IPC_CREAT | 0700 ) ) == -1 )
err_sys ( "semget error" ) ;
init ( p_semid, 0 ) ;
if ( ( p_shmid = shmget ( p_key, 8192, IPC_CREAT | 0700 ) ) == -1 )
err_sys ( "shmget" ) ;
write_shm ( p_semid, p_shmid, "No Data" ) ;
if ( listen (ssd, MAXCLIENT) )
err_quit ( "listen error" ) ;
length = sizeof(sa);
L_Client = MakeEmpty ( L_Client ) ;
i = 0 ;
while ( flag ) {
sigsetjmp ( s_env, savesig ) ;
printf ( "Waiting for Connection...\n" ) ;
if ((csd = accept(ssd, (struct sockaddr *)&caller, &length)) < 0)
err_sys ( "acccept" ) ;
if ( sigprocmask ( SIG_BLOCK, &usr2mask, &savemask ) < 0 )
err_quit ( "sigprocmask error" ) ;
if ( c_count == MAXCLIENT ) {
send ( csd, "server is too busy!!!\n", 23, MSG_DONTWAIT ) ;
if ( sigprocmask ( SIG_SETMASK, &savemask, NULL ) < 0 )
err_quit ( "sigprocmask error" ) ;
close( csd ) ;
siglongjmp ( s_env, 0 ) ;
}
c_data = malloc ( sizeof ( struct client_ds ) ) ;
if ( ( n = recv ( csd, cnt_name, sizeof(cnt_name), 0 ) ) < 0 )
err_sys ( "read error" ) ;
if ( cnt_name[ n-1 ] == '\n' )
cnt_name[ n-1 ] = 0 ;
cnt_name[ n ] = 0 ;
strcpy ( c_data->c_name, cnt_name ) ;
if ( ( c_data->c_semid = semget ( ++key, 1, IPC_CREAT | 0700 ) ) == -1 )
err_sys ( "semget error" ) ;
init ( c_data->c_semid, 0 ) ;
if ( ( c_data->c_shmid = shmget ( key, 8192, IPC_CREAT | 0700 ) ) == -1 )
err_sys ( "shmget" ) ;
write_shm ( c_data->c_semid, c_data->c_shmid, "No Data" ) ;
c_data->c_fd = csd ;
c_data->c_pid = 0 ;
printf ( "Client is connected %d\n", csd ) ;
if ( ( pid = fork ( ) ) == -1 )
err_sys ( "fork error" ) ;
else if ( pid == 0 ) {
close( ssd ) ;
if ( handle_client ( c_data ) != 0 )
err_sys ( "error handling client" ) ;
printf ( "Exiting\n" ) ;
exit ( 0 ) ;
}
c_data->c_pid = pid ;
if ( waitpid ( pid, NULL, WNOHANG ) == -1 )
err_sys ( "waitpid error" );
Insert ( c_data, L_Client, L_Client ) ;
c_count++ ;
if ( sigprocmask ( SIG_SETMASK, &savemask, NULL ) < 0 )
err_quit ( "sigprocmask error" ) ;
}
close(ssd);
printf ( "Removing Public Shared memory\n" ) ;
semdel ( p_semid ) ;
shmdel ( p_shmid ) ;
exit(0);
}
void send_private( int sno )
{
int i ;
Position Pos, TmpPos;
char touser[ NAMSIZ ], Buf[ MAXBUF ], Tmp[ MAXBUF ] ;
Pos = L_Client->Next ;
while ( Pos != NULL ) {
if (sempid(Pos->Element->c_semid, 0)==Pos->Element->c_pid) {
read_shm ( Pos->Element->c_semid, Pos->Element->c_shmid, Buf ) ;
printf ( "Message Got :%s:\n", Buf ) ;
if ( strcmp ( Buf, "Quit" ) == 0 ) {
write_shm ( Pos->Element->c_semid, Pos->Element->c_shmid, "Finished" ) ;
if ( waitpid ( Pos->Element->c_pid, NULL, 0 ) == -1 )
err_sys ( "waitpid error" ) ;
semdel ( Pos->Element->c_semid ) ;
shmdel ( Pos->Element->c_shmid ) ;
close ( Pos->Element->c_fd ) ;
printf ( "Removing the user from List >>%s<<\n", Pos->Element->c_name ) ;
Delete ( Pos->Element->c_name, L_Client ) ;
c_count-- ;
printf ( "Client Process Removed\n" ) ;
return ;
} else if ( strcmp ( Buf, "list" ) == 0 ) {
printf ( "Got Message from %s To List Users\n", Pos->Element->c_name ) ;
TmpPos = L_Client->Next ;
while ( TmpPos != NULL ) {
sprintf ( Tmp, "%s\n", TmpPos->Element->c_name ) ;
send ( Pos->Element->c_fd, Tmp, strlen ( Tmp ), MSG_DONTWAIT ) ;
TmpPos = TmpPos->Next ;
}
send( Pos->Element->c_fd, prompt[0], strlen(prompt[0]), MSG_DONTWAIT);
write_shm ( Pos->Element->c_semid, Pos->Element->c_shmid, "No Data" ) ;
return ;
} else {
touser[ 0 ] = '\0' ;
for ( i = 1; Buf[ i ] != '>'; i++ )
touser[ i-1 ] = Buf[ i ];
touser[ i-1 ] = '\0' ;
printf ( "Searching For User %s\n", touser ) ;
TmpPos = Find ( touser, L_Client ) ;
if ( TmpPos == NULL ) {
printf ( "%s: User Not Available\n", touser ) ;
sprintf ( Tmp, "%s: User Not Available\n>>", touser ) ;
send ( Pos->Element->c_fd, Tmp, strlen ( Tmp ), MSG_DONTWAIT ) ;
write_shm ( Pos->Element->c_semid, Pos->Element->c_shmid, "No Data" ) ;
return ;
}
printf ( "%s: User Available\n", touser ) ;
sprintf ( Tmp, "PRIVATE Message From %s: %s\n>>", Pos->Element->c_name, &Buf[ i+1 ] ) ;
printf ( "PRIVATE Message From %s: %s\n", Pos->Element->c_name, &Buf[ i+1 ] ) ;
send ( TmpPos->Element->c_fd, Tmp, strlen ( Tmp ), MSG_DONTWAIT ) ;
sprintf ( Tmp, "Message Has been recevied by %s\n>>", touser ) ;
printf ( "Message Has been recevied by %s\n", touser ) ;
send ( Pos->Element->c_fd, Tmp, strlen ( Tmp ), MSG_DONTWAIT ) ;
write_shm ( Pos->Element->c_semid, Pos->Element->c_shmid, "No Data" ) ;
}
}
Pos = Pos->Next ;
}
}
