main()
{
int childpid;
if(childpid=fork()<0) exit(0); if(childpid>0)
{
printf("***Parent Process***\n");
printf("My pid=%d\nMy parent pid=%d\n",getpid(),getppid());
while(wait((int *)0)!=childpid);
}
else
{
printf("***Child process***\n");
printf("My pid=%d\nMy parentpid=%d\n",getpid(),getppid());
}
}
Output:
[mtechcs@cse11 007]$ ./a.out
***Child process***
My pid=6543
My parentpid=6542
***Parent process***
My pid=6542
My parentpid=6507
[mtechcs@cse11 007]$
//Pipes (pipes.c)
#define MAX 100
main()
{
int childpid,pipe1[2],pipe2[2],nread,nwrite;
char buff[MAX];
//pipe(pipe1);
//pipe(pipe2);
if((pipe(pipe1)<0||pipe(pipe2)<0)) { printf("ERROR: pipes not created"); exit(0); } if((childpid=fork())<0) { printf("error in process\n"); exit(0); } if(childpid>0)
{
printf("writing to the server\n");
close(pipe1[0]);
close(pipe2[1]);
nread=read(0,buff,MAX);
nwrite=write(pipe1[1],buff,nread);
if(nread!=nwrite)
printf("Write Error");
nread=read(pipe2[0],buff,MAX);
nwrite=write(1,buff,nread);
if(nread!=nwrite)
printf("Standard Output Error\n");
while(wait((int*)0)!=childpid);
close(pipe1[1]);
close(pipe2[0]);
exit(0);
}
else
{
close(pipe1[1]);
close(pipe2[0]);
nread=read(pipe1[0],buff,MAX);
strcat(buff,"from the server");
nread=strlen(buff);
nwrite=write(pipe2[1],buff,nread);
close(pipe1[0]);
close(pipe2[1]);
exit(0);
}
}
Output:
[mtechcs@cse11 007]$ cc pipes.c
[mtechcs@cse11 007]$ ./a.out
Writing to the server
Pipes created
Pipes created
from the server[mtechcs@cse11 007]$
//Related FIFO (relfifo.c)
#include
#define MAX 100
#define FIFO1 "./FIFO1"
#define FIFO2 "./FIFO2"
#define PERMS 0666
main()
{
int childpid,readfd,writefd,nread,nwrite;
char buff[MAX];
if(mknod(FIFO1,S_IFIFO|PERMS,0)<0) printf("FIFO1 created\n"); if(mknod(FIFO2,S_IFIFO|PERMS,0)<0) printf("FIFO2 created\n"); else unlink(FIFO1); if((childpid=fork())<0) { printf("error in process\n"); exit(0); } if(childpid>0)
{
printf("***Parent Process***\nWriting to the server\n");
writefd=open(FIFO1,1);
readfd=open(FIFO2,0);
nread=read(0,buff,MAX);
nwrite=write(writefd,buff,nread);
if(nread!=nwrite)
printf("Write Error!\n");
nread=read(readfd,buff,MAX);
nwrite=write(1,buff,nread);
if(nread!=nwrite)
printf("Standard Output Error\n");
while(wait((int*)0)!=childpid);
close(readfd);
close(writefd);
unlink(FIFO1);
unlink(FIFO2);
exit(0);
}
else
{
readfd=open(FIFO1,0);
writefd=open(FIFO2,1);
nread=read(readfd,buff,MAX);
strcat(buff,"from the server");
nread=strlen(buff);
nwrite=write(writefd,buff,nread);
close(readfd);
close(writefd);
exit(0);
}
}
Output:
[mtechcs@cse11 007]$ cc relfifo.c
[mtechcs@cse11 007]$ ./a.out
FIFO1 created
FIFO2 created
***Parent process***
Writing to the server
M.Tech IT
M.Tech IT
from the server Write error!
[mtechcs@cse11 007]$
// Unrelated FIFO
//Server (servfifo.c)
#include"myfifo.h"
main()
{
int childpid,readfd,writefd,nread,nwrite;
char buff[MAX];
if(mknod(FIFO1,S_IFIFO|PERMS,0)<0) printf("FIFO1 created\n"); if(mknod(FIFO2,S_IFIFO|PERMS,0)<0) printf("FIFO2 created\n"); else unlink(FIFO1); if((childpid=fork())<0) { printf("error in process\n"); exit(0); } if(childpid>0)
{
printf("***Parent Process***\nWriting to the server\n");
readfd=open(FIFO1,1);
writefd=open(FIFO2,0);
nread=read(readfd,buff,MAX);
nwrite=write(writefd,buff,nread);
if(nread!=nwrite)
printf("Write Error\n");
nread=read(readfd,buff,MAX);
nwrite=write(1,buff,nread);
if(nread!=nwrite)
printf("Standard Output Error\n");
while(wait((int*)0)!=childpid);
exit(0);
}
}
//Client (clififo.c)
#include"myfifo.h"
jcjmain()
{
int childpid,readfd,writefd,nread,nwrite;
char buff[MAX];
printf("***Child Process***\n");
writefd=open(FIFO1,1);
readfd=open(FIFO2,0);
nread=read(0,buff,MAX);
strcat(buff,"from the server");
nread=strlen(buff);
nwrite=write(writefd,buff,nread);
close(readfd);
close(writefd);
unlink(FIFO1);
unlink(FIFO2);
exit(0);
}
//Header file (myfifo.h)
#include
#define MAX 100
#define PERMS 0666
#define FIFO1 "/user/tmp/FIFO1"
#define FIFO2 "/user/tmp/FIFO2"
Output:
[mtechcs@cse11 007]$cc –o client clififo.c
[mtechcs@cse11 007]$cc –o server servfifo.c
[mtechcs@cse11 007]$./server&
[mtechcs@cse11 007]$./client
FIFO1 created
FIFO2 created
***Parent Process***
Writing to the server
hello
***Client Process***
hello
from the server
//Message Queues
//Header File (mymsg.h)
#include
#include
#include
#include
#define PERMS 0666
#define MHDRSIZE sizeof(mesg)-MAXDATASIZE;
#define MAXDATASIZE 1024
#define MKEY1 1234L
#define MKEY2 2345L
typedef struct msgbuff{
int mesg_len;
long int mesg_type;
char mesg_data[MAXDATASIZE];
}mesg;
//Client (climsg.c)
#include"mymsg.h"
main()
{
int readqid,writeqid;
writeqid=msgget(MKEY1,0);
readqid=msgget(MKEY2,0);
client(readqid,writeqid);
msgctl(readqid,IPC_RMID,0);
msgctl(writeqid,IPC_RMID,0);
exit(0);
}
client(readqid,writeqid)
{
int len,nread;
mesg message;
nread=read(0,message.mesg_data,MAXDATASIZE);
message.mesg_type=1;
msgsnd(writeqid,(struct type *)message.msgbuff,nread,0);
msgrcv(readqid,message.mesg_data,message.mesg_len,0,0);
write(1,message.mesg_data,MAXDATASIZE);
}
//Server (servmsg.c)
#include"mymsg.h"
mesg message;
int nread;
main()
{
int readqid,writeqid;
readqid=msgget(MKEY1,PERMS|IPC_CREAT);
writeqid=msgget(MKEY2,PERMS|IPC_CREAT);
server(readqid,writeqid);
exit(0);
}
server(readqid,writeqid)
{
msgrcv(readqid,message.mesg_data,MAXDATASIZE,message.mesg_type,0);
msgsnd(writeqid,(struct type *)msgbuff,nread,0);
}
//Shared memory
//Header File (myshm.h)
#include
#include
#include
#define PERMS 0666
#define MHDRSIZE sizeof(mesg)-MAXDATASIZE;
#define MAXDATASIZE 100
#define SHMKEY 1234L
typedef struct msgbuff{
int mesg_len;
long int mesg_type;
char mesg_data[MAXDATASIZE];
}mesg;
//Server (servshm.c)
#include"myshm.h"
mesg *msgptr;
main()
{
int shmid;
shmid=shmget(SHMKEY,sizeof(mesg),PERMS|IPC_CREAT);
msgptr=(mesg *)shmat(shmid,0,0);
strcat(msgptr->mesg_data,"FROM SERVER");
mshptr->mesg_type=2L;
msgptr->mesg_len=strlen(msgptr->mesg_data);
}
//Client (clishm.c)
#include"myshm.h"
Mesg *msgptr;
main()
{
int shmid;
shmid=shmget(SHMKEY,sizeof(mesg),0);
msgptr=(mesg *)shmat(shmid,0,0);
nread=read(0,msgptr->mesg_data,MAXDATASIZE);
msgptr->mesg_len=nread;
msgptr->mesg_type=1L;
write(1,msgptr->mesg_data,msgptr->mesg_len);
shmdt(msgptr);
shmctl(shmid,IPC_RMID,0);
}
//Semaphores
//Header File (mysem.h)
#include
#include
#include
#define PERMS 0666
#define MHDRSIZE sizeof(mesg)-MAXDATASIZE;
#define MAXDATASIZE 1024
#define SHMKEY 4567L
#define SEMKEY1 1234L
#define SEMKEY2 2345L
typedef struct msgbuff{
int mesg_len;
long int mesg_type;
char mesg_data[MAXDATASIZE];
}mesg;
int shmid,semid;
typedef struct sembuff{
short sem_num;
short sem_op;
short sem_flg;
}semp;
static struct sembuff myop_lock[2]= {
0,0,0;
0,1,SEM_UNDO;
};
static struct sembuff myop_unlock[1]={
0,-1,SEM_UNDO;
};
Static struct sembuff op_endcrete[2]={
1,-1,SEM_UNDO;
2,-1,SEM_UNDO;
};
static struct sembuff op_lock[2]= {
0,0,0;
0,1,SEM_UNDO;
};
static struct sembuff op_open[1]= {
1,-1,SEM_UNDO;
};
static struct sembuff op_close[3]={
2, 0, 0,
2, 1, SEM_UNDO,
1, 1, SEM_UNDO
};
Static stuct sembuff op_unlock[1]={
2,-1,SEM_UNDO;
};
//sem_create
int sem_create(int key,int initval)
{
int semid,semval;
semid=semget(key,3,PERMS|IPC_CREAT);
if(initval==0)
semop(semid,&op_lock[0],2);
if((semval=semctl(semid,1,GETVAL,0))==0)
semctl(semid,1,SETVAL,BIGCOUNT)
semctl(semid,0,SETVAL,initval);
semop(semid,&op_endcreate[0],2);
return(semid);
}
//sem_open
int sem_open(int key)
{
int semid;
semid=semget(key,3,0);
if(semid<0) printf(“UNSUCCESSFULL”); semop(id,&op_open[0],1); return(semid); } //sem_close sem_close(int semid) { int semval; semop(id,&op_close[0],3); if((semval=semctl(id,1,GETVAL,0))==BIGCOUNT) sem_rm(semid); else semop(id,&op_unlock[0],1); return(semid); } //sem_wait sem_wait(int semid,value) { op_op[0].val=value semop(semid,&op_op[0],1); } //sem_signal sem_signal(int semid) { op_op[0].val=value; semop(semid,&op_ops[0],1); } //sem_rm Sem_rm(semid) { Semctl(semid,IPC_RMID,0); } //Server #include"mysem.h" main() { mesg msgptr; shmid=shmget(SHMKEY,sizeof(mesg),PERMS|IPC_CREAT); msgptr=(mesg *)shmat(shmid,0,0); clisem=sem_create(SEMKEY2,0); servsem=sem_create(SEMKEY1,1); sem_wait(clisem); server(); shmdt(msgptr); } server() { strcat(msgptr->mesg_data,"from server");
msgptr->mesg_len=strlen();
msgptr->mesg_type=2L;
sem_signal(servsem);
}
//Client
#include"mysem.h"
main()
{
Mesg msgptr;
shmid=shmget(SHMKEY,0,0);
msgptr=(Mesg *)shmat(shmid,0,0);
sem_wait(servsem);
client();
shmdt(msgptr);
shmctl(shmid,IPC_RMID,0);
sem_rm(clisem);
sem_rm(servsem);
client()
{
read(0,msgptr->mesg_data,MAXDATASIZE);
sem_signal(clisem);
sem_wait(servsem);
write(1,msgptr->mesg_data,msgptr->mesg_len);
}
//TCP client server Application
//tcp_echo header (tcp_header.h)
#include
#include
#define SERV_PORT 9999
#define MAXSIZE 1024
#define SERV_ADDR "172.16.5.80"
//readn function
readn(fd,buff,nbytes)
{
int fd,nbytes,nleft,nread;
pbuff=buff;
nleft=nbytes
while(nleft>0)
{
nread=read(fd,pbuff,nleft);
if(nread==0)
break;
if(nread<0) nleft=nleft-nread; buff=pbuff+nread; } return(nbytes-nleft); } //writen function writen(fd,buff,nbytes) { int fd,nbytes,nleft,nwrite; pbuff=buff; nleft=nbytes; while(nleft>0)
{
nwrite=write(fd,pbuff,nleft)
if(nwrite<0) nleft=nleft-nwrite; buff=pbuff+nwrite; } return(nbytes-nleft); } //tcp echo server
#include”tcp_header.h”
main()
{
int listenfd,connfd,clilen,n;
struct sockaddr_in servaddr,cliaddr;
listenfd=socket(AF_INET,SOCK_STREAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDRANY);
servaddr.sin_port=htons(SERV_PORT);
bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));
listen(listenfd,6);
for(;;)
{
clilen=sizeof(cliaddr);
connfd=accept(listenfd,(struct sockaddr *)&cliaddr,&clilen);
n=readn(connfd,buff,MAXBUFF);
writen(connfd,buff,n);
exit(0);
close(connfd);
}
}
//tcp_echo client
#include”tcp_header.h”
main()
{
int sockfd,n;
struct sockaddr_in servaddr;
sockfd=socket(AF_INET,SOCK_STREAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(SERV_PORT);
servaddr.sin_addr.s_addr=htonl(inet_addr(SERV_ADDR);
connect(sockfd,(struct sockaddr *)servaddr,sizeof(servaddr));
n=read(0,buff,BUFFSIZE);
writen(sockfd,buff,n);
n=readn(sockfd,buff,BUFFSIZE);
write(1,buff,n);
close(sockfd);
}
//UDP client server Application
//udp echo server
#include
#include
#include
#define SERV_PORT 9999
#define MAXSIZE 1024
main()
{
int nbytes,sockfd;
char buff[MAXSIZE];
struct sockaddr_in servaddr,cliaddr;
sockfd=socket(AF_INET,SOCK_DGRAM,0);
nbytes=read(0,buff,MAXSIZE);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(SERV_PORT);
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
bind(sockfd,(struct sockaddr *)servaddr,sizeof(servaddr));
for(;;)
{
clilen=sizeof(cliaddr);
recvfrom(sockfd,buff,MAXSIZE,(struct sockaddr *)cliaddr,&clilen);
strcat(buff,”FROM THE SERVER”);
n=strlen(buff);
sendto(sockfd,buff,n,0,(struct sockaddr *)cliaddr,sizeof(cliaddr));
}
//udp echo client
#include
#include
#include
#define SERV_PORT 9999
#define MAXSIZE 1024
main()
{
int nbytes,sockfd;
char buff[MAXSIZE];
struct sockaddr_in servaddr,cliaddr;
sockfd=socket(AF_INET,SOCK_DGRAM,0);
nbytes=read(0,buff,MAXSIZE);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(SERV_PORT);
servaddr.sin_addr.s_addr=htonl(Inetaddr("172.16.5.80"));
sendto(sockfd,buff,nbytes,0,(struct sockaddr *)servaddr,sizeof(servaddr));
n=recvfrom(sockfd,buff,MAXSIZE,(struct sockaddr *)cliaddr,&sizeof(cliaddr));
write(1,buff,n);
}
