static void sighandler(int p)
{
if(p == SIGUSR1)
{
signal(SIGUSR1,sighandler);
int cm = *x;
printf("Signalled %d\n",cm);
if(cm==0)
{
if(count>=1)
send_file_descriptor(ucss[cm],sq[(--count)]);
else
flag[cm] = 0;
}
else if(cm==1)
{
if(count>=1)
send_file_descriptor(ucss[cm],sq[(--count)]);
else
flag[cm] = 0;
}
else if(cm==2)
{
if(count>=1)
send_file_descriptor(ucss[cm],sq[(--count)]);
else
flag[cm] = 0;
}
sbuf.sem_op = 1;
semop(sem,&sbuf,1);
}
}
int main() {
int fd[2] = {-1, -1};
int server = -1, client = -1;
FILE *fp = NULL;
FILE *fp2 = NULL;
fp = fopen("a.txt", "w");
if (fp == NULL) {
fprintf(stderr, "fopen(a.txt) failed: %s\n", strerror(errno));
goto ERR_FOPEN;
}
fd[0] = fileno(fp);
printf("a.txt:%d\n", fd[0]);
fp2 = fopen("aa.txt", "w");
if (fp2 == NULL) {
fprintf(stderr, "fopen(aa.txt) failed: %s\n", strerror(errno));
goto ERR_FOPEN;
}
fd[1] = fileno(fp2);
printf("aa.txt:%d\n", fd[1]);
server = create_server();
if (server < 0) {
fprintf(stderr, "create_server failed\n");
goto ERR_CREATE_SERVER;
}
while(1) {
client = accept(server, NULL, NULL);
fprintf(stderr, "client accept %d\n", client);
if (client < 0) {
fprintf(stderr, "accept failed\n");
goto ERR_ACCEPT;
}
if (send_file_descriptor(client, fd) < 0) {
fprintf(stderr, "send_file_descriptor failed: %s\n", strerror(errno));
goto ERR_SEND_FILE_DESCRIPTOR;
}
if (shutdown(client, SHUT_RDWR) < 0) {
fprintf(stderr, "shutdown failed: %s\n", strerror(errno));
goto ERR_SHUTDOWN;
}
}
ERR_SHUTDOWN:
ERR_SEND_FILE_DESCRIPTOR:
close(client);
ERR_ACCEPT:
close(server);
ERR_CREATE_SERVER:
fclose(fp);
fclose(fp2);
ERR_FOPEN:
return 0;
}
static void
do_server(int shmfd)
{
int listenfd;
listenfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (listenfd == -1) {
perror("socket");
exit(EXIT_FAILURE);
}
struct sockaddr_un saddr = {0};
saddr.sun_family = AF_UNIX;
strcpy(saddr.sun_path, UNIX_DOMAIN_PATH);
unlink(saddr.sun_path);
if (bind(listenfd, (struct sockaddr*)&saddr, sizeof(struct sockaddr_un)) == -1) {
perror("bind");
goto error;
}
if (listen(listenfd, 128) == -1) {
perror("listen");
goto error;
}
int sockfd;
sockfd = accept(listenfd, NULL, NULL);
if (sockfd == -1) {
perror("accept");
goto error;
}
setnonblocking(sockfd);
send_file_descriptor(sockfd, shmfd);
close(sockfd);
close(listenfd);
unlink(saddr.sun_path);
return;
error:
close(listenfd);
exit(EXIT_FAILURE);
}
int main()
{
int sfd,sfd1;
struct sockaddr_un serv_addr,client_addr;
struct sockaddr_un serv_addrs;
int len=sizeof(client_addr);
serv_addr.sun_family=AF_UNIX;
strcpy(serv_addr.sun_path,"echo_socket_c");
serv_addrs.sun_family=AF_UNIX;
strcpy(serv_addrs.sun_path,"echo_socket_cs");
sfd1=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd1,"socket error");
error_func(connect(sfd1,(struct sockaddr*)&serv_addrs,sizeof(serv_addrs)),"connect error");
send(sfd1,"From server c to server s",30,0);
sfd=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd,"socket error");
unlink(serv_addr.sun_path);
error_func(bind(sfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)),"bind error");
error_func(listen(sfd,5),"listen error");
char buffer[30];
int nfd=accept(sfd,(struct sockaddr*)&client_addr,&len);
error_func(nfd,"accept error");
recv(nfd,buffer,sizeof(buffer),0);
printf("%s\n",buffer);
int clients_no=0;
while(1)
{
int fd=recv_file_descriptor(nfd);
printf("File descriptor%d\n",fd);
if(clients_no>=max_clients)
{
printf("%s\n","max reached of server c");
send_file_descriptor(sfd1,fd);
}
else
pthread_create(&threads[clients_no++],NULL,func,(void *)(&fd));
}
}
void handler_func()
{
kill(pid,SIGUSR1); //signal backupserver
printf("%s\n","The server is about to shutdown");
int i;
printf("count of no_cients%d\n",clients_no);
for(i=0;i<max_clients;i++)
{
if(cfd[i]==-1) break;
printf("fd %d\n",cfd[i]);
send_file_descriptor(bsfd,cfd[i]);
}
exit(0);
}
int main()
{
int pid=0;
pid=fork();
if(pid==0)
{
sleep(5);
printf("%s\n","child process");
int sfd;
struct sockaddr_un serv_addr;
serv_addr.sun_family=AF_UNIX;
strcpy(serv_addr.sun_path,"echo_socket");
sfd=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd,"socket error");
error_func(connect(sfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)),"connect error");
int fd=recv_file_descriptor(sfd);
printf("fd is child: %d\n",fd);
char buffer[30];
int nbytes;
while(1)
{
scanf("parent bytes?%d",&nbytes);
read(fd,buffer,nbytes);
printf("child :%s\n",buffer);
sleep(3);
}
send(sfd,"From client to server",30,0);
recv(sfd,buffer,sizeof(buffer),0);
printf("%s\n",buffer);
close(sfd);
}
else
{
printf("%s\n","parent process");
const char *filename = "sample.txt";
int fd = open(filename, O_RDWR);
printf("fd parent:%d\n",fd);
int sfd;
struct sockaddr_un serv_addr,client_addr;
int len=sizeof(client_addr);
serv_addr.sun_family=AF_UNIX;
strcpy(serv_addr.sun_path,"echo_socket");
sfd=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd,"socket error");
unlink(serv_addr.sun_path);
error_func(bind(sfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)),"bind error");
error_func(listen(sfd,5),"listen error");
int nfd=accept(sfd,(struct sockaddr*)&client_addr,&len);
error_func(nfd,"accept error");
send_file_descriptor(nfd,fd);
int nbytes;
char buffer1[30];
while(1)
{
scanf("parent bytes?%d",&nbytes);
read(fd,buffer1,nbytes);
printf("parent :%s\n",buffer1);
sleep(3);
}
char buffer[30];
recv(nfd,buffer,sizeof(buffer),0);
printf("%s\n",buffer);
send(nfd,"hello from server",30,0);
wait(NULL);
close(nfd);
close(sfd);
}
}
int main(void)
{
int uss, bsfd[3], thop, len,sfd,sf;
struct sockaddr_un local, remote;
struct sockaddr_in ser_addr,cli_addr;
char str[100];
signal(SIGUSR1,sighandler);
sem = semget(134,1,IPC_CREAT|0666);
semctl(sem,0,SETVAL,1);
xid = shmget(123,4,IPC_CREAT|0666);
x = shmat(xid,NULL,0);
int i=0;
for(i=0; i<3; i++)
{
bsfd[i] = socket(AF_INET,SOCK_STREAM,0); // socket create... AF_INET for IPv4 domain and SOCK_STREAM for connection oriented systems
if(bsfd[i] < 0)
perror("Socket create");
}
memset(&ser_addr,0,sizeof(struct sockaddr_in)); // Initialize to 0
memset(&cli_addr,0,sizeof(struct sockaddr_in));
ser_addr.sin_family = AF_INET;
int portno = 27234;
ser_addr.sin_port = htons(portno); // converts int to 16 bit integer in network byte order
ser_addr.sin_addr.s_addr = INADDR_ANY; // to get IP address of machine on which server is running
for(i=0; i<3; i++)
{
if(bind(bsfd[i],(struct sockaddr*)&ser_addr,sizeof(struct sockaddr_in))<0)
perror("Bind error");
portno++;
ser_addr.sin_port = htons(portno);
}
for(i=0; i<3; i++)
printf("%d\n",bsfd[i] );
for(i=0; i<3; i++)
if(listen(bsfd[i],10)<0) // No. of clients that server can service
perror("Listen error");
/*UNIX SOCKETS*/
if ((uss = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
local.sun_family = AF_UNIX;
strcpy(local.sun_path, SOCK_PATH1);
unlink(local.sun_path);
len = strlen(local.sun_path) + sizeof(local.sun_family);
if (bind(uss, (struct sockaddr *)&local, len) == -1) {
perror("bind");
exit(1);
}
if (listen(uss, 5) == -1) {
perror("listen");
exit(1);
}
// int css[3];
int selfpid = getpid();
for(i=0; i<3; i++)
{
char pid[10] = {'\0'};
while((ucss[i] = accept(uss, (struct sockaddr *)&remote, &thop))<0);
printf(" FD %d\n",ucss[i]);
while(recv(ucss[i],pid,sizeof(pid),0)<=0);//printf("H");
printf("Received %s\n",pid );
pids[i] = atoi(pid);
//itoa(selfpid,pid,10);
snprintf(pid,10,"%d\n",selfpid);
send(ucss[i],pid,sizeof(pid),0);
printf("%d",pids[i]);
}
printf("PIDS EXCHANGED\n");
for(i=0; i<3; i++)
{
printf("%d\n",ucss[i] );
flag[i] = 0;
count = 0;
}
fd_set readfds;
struct timespec tim_dur;
tim_dur.tv_sec = 5; // waiting time of 1 sec for verifying set bits of FDSET
tim_dur.tv_nsec = 0;
while(1)
{
FD_ZERO(&readfds);
FD_SET(bsfd[0],&readfds);
FD_SET(bsfd[1],&readfds);
FD_SET(bsfd[2],&readfds);
int max = bsfd[0];
for(i=0; i<3; i++)
if(max<bsfd[i])
max=bsfd[i];
if(pselect(max+1,&readfds,NULL,NULL,&tim_dur,NULL)>0) // pselect is used as timeleft is not updated after each select call
{
for(i=0; i<3; i++)
{
if(FD_ISSET(bsfd[i],&readfds))
{
printf("Client came have fun mr.server :P\n");
int nsfd = accept(bsfd[i], (struct sockaddr *)&remote, &thop); // Type cast sockaddr_in to sockaddr and pass by reference and pointer of length to be passed
if(nsfd < 0)
perror("Accept error");
int cm = i;
printf("Selected %d\n",cm );
int j=0;
for(j=0; j<3; j++)
printf("%d\n",flag[j] );
printf("\n");
for(j=0; j<3; j++)
if(flag[j]==0)
break;
printf("%d\n",j );
if(j<3)
{
printf("CSS %d nsfd %d\n",ucss[j],nsfd );
printf("%d\n",send_file_descriptor(ucss[j],nsfd));
flag[j]=1;
}
else
{
char sry[10];
strcpy(sry,"Wait!!");
send(nsfd,sry,sizeof(sry),0);
sq[count++] = nsfd;
}
}
}
}
}
return 0;
}
int main()
{
int sfd,sfdcs,sfd1;
struct sockaddr_un serv_addr,client_addr;
struct sockaddr_un serv_addrcs,client_addres; //address of server1
struct sockaddr_un serv_addrs;
int lencs=sizeof(client_addres);
int len=sizeof(client_addr);
serv_addr.sun_family=AF_UNIX;
strcpy(serv_addr.sun_path,"echo_socket_s");
serv_addrs.sun_family=AF_UNIX;
strcpy(serv_addrs.sun_path,"echo_socket_se");
serv_addrcs.sun_family=AF_UNIX;
strcpy(serv_addrcs.sun_path,"echo_socket_cs");
sfdcs=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfdcs,"socket error");
sfd1=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd1,"socket error");
error_func(connect(sfd1,(struct sockaddr*)&serv_addrs,sizeof(serv_addrs)),"connect error");
send(sfd1,"From server s to server e",30,0);
sfd=socket(AF_UNIX,SOCK_STREAM,0);
error_func(sfd,"socket error");
unlink(serv_addr.sun_path);
unlink(serv_addrcs.sun_path);
error_func(bind(sfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr)),"bind error");
error_func(listen(sfd,5),"listen error");
error_func(bind(sfdcs,(struct sockaddr*)&serv_addrcs,sizeof(serv_addrcs)),"bind error");
error_func(listen(sfdcs,5),"listen error");
int nfdcs=accept(sfdcs,(struct sockaddr*)&client_addres,&lencs);
error_func(nfdcs,"accept error");
char buffer[30];
recv(nfdcs,buffer,sizeof(buffer),0);
printf("%s\n",buffer);
int nfd=accept(sfd,(struct sockaddr*)&client_addr,&len);
error_func(nfd,"accept error");
recv(nfd,buffer,sizeof(buffer),0);
printf("%s\n",buffer);
struct pollfd fdp[2];
fdp[0].fd=nfd;
fdp[0].events=POLLRDNORM;
fdp[1].fd=nfdcs;
fdp[1].events=POLLRDNORM;
int clients_no=0;
while(1)
{
error_func(poll(fdp,2,0),"poll error");
if(fdp[0].events & fdp[0].revents)
{
printf("%s\n","0 main selected");
int fd=recv_file_descriptor(nfd);
printf("File descriptor%d\n",fd);
if(clients_no >=max_clients)
{
//send clients to e server
printf("%s\n","max of s reached sending to e server");
send_file_descriptor(sfd1,fd);
perror("send:");
}
else
pthread_create(&threads[clients_no++],NULL,func,(void *)(&fd));
}
else if(fdp[1].events & fdp[1].revents)
{
printf("%s\n","1 s server selected");
int fd=recv_file_descriptor(nfdcs);
printf("File descriptor%d\n",fd);
if(clients_no>=max_clients)
{
//send clients to e server
printf("%s\n","max of s reached sending to e server");
send_file_descriptor(sfd1,fd);
perror("send:");
}
else
pthread_create(&threads[clients_no++],NULL,func,(void *)(&fd));
}
else
continue;
}
}
