coperating-systemipc
How to chat with client from a server using FIFO with select system call?
Hi there i am trying to make such a program in which the the two fds stdin and fifo monitor by select() and communicate with each other.
select() will monitor either fifo ready for reading or stdin.
server.c
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/select.h>
int main(int argc,char *argv[]){
int f,fifo_read,fifo_write,status;
fd_set readset;
FD_ZERO(&readset);
char str[512]="start";
if(argc !=2)
if(argc != 2){
printf("\nError: %s required argument [Fifo Name]\n\n",argv[0]);
exit(EXIT_FAILURE);
}
if ((open(argv[1], O_RDWR)) < 0){
f = mkfifo(argv[1],S_IRWXU);
if(f<0){
perror("Error While Creating FIFO ");
exit(EXIT_FAILURE);
}
else
printf("FIFO Created Successfully...\n");
}
while(strcmp(str,"end")!=0){
fifo_write= open(argv[1],O_WRONLY);
FD_SET(fifo_read, &readset);
FD_SET(STDIN_FILENO, &readset);
status = select(fifo_read+1, &readset, NULL, NULL, NULL);
if(status==-1){
perror("Error While Calling select() system call ");
//exit(EXIT_FAILURE);
}
if(FD_ISSET(STDIN_FILENO,&readset)){
if(fifo_write<0)
perror("\nError while writing on pipe ");
else{
printf("\nServer>> ");
scanf("%s",str);
write(fifo_write,str,strlen(str));
close(fifo_write);
}
}
fifo_read=open(argv[1],O_RDONLY);
if(FD_ISSET(fifo_read,&readset)){
if(fifo_read<0)
perror("\nError while reading from pipe ");
else{
read(fifo_read,str,strlen(str));
close(fifo_read);
printf("\nJiya%s",str);
}
}
}
return 0;
}
client.c
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/select.h>
int main(int argc,char *argv[]){
int f,fifo_read,fifo_write,status;
fd_set readset;
FD_ZERO(&readset);
char str[512]="start";
while(strcmp(str,"end")!=0){
fifo_write= open(argv[1],O_WRONLY);
FD_SET(fifo_read, &readset);
FD_SET(STDIN_FILENO, &readset);
status = select(fifo_read+1, &readset, NULL, NULL, NULL);
if(status==-1){
perror("Error While Calling select() system call ");
//exit(EXIT_FAILURE);
}
if(FD_ISSET(fifo_read,&readset)){
if(fifo_read<0)
printf("\nError opening read pipe");
else{
read(fifo_read,str,strlen(str));
close(fifo_read);
printf("\n%s",str);
}
}
fifo_read=open(argv[1],O_RDONLY);
if(FD_ISSET(STDIN_FILENO,&readset)){
if(fifo_write<0)
printf("\nError opening write pipe");
else{
printf("\nClient>> ");
scanf("%s",str);
write(fifo_write,str,strlen(str));
close(fifo_write);
}
}
}
return 0;
}
Solution
Here i Got the Solution :)
server.c
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/select.h>
#include <string.h>
#include <sys/stat.h>
#include <errno.h>
int main(int argc, char *argv[])
{
if(argc != 2){
printf("\nError: %s required argument [Fifo Name]\n\n",argv[0]);
exit(EXIT_FAILURE);
}
int fd,wr,rd,ret;
fd_set readset;
if(mkfifo(argv[1],S_IRWXU)==-1){
if(errno!=EEXIST)
perror("Error unable to create FIFO ");
else
perror("Error unable to create FIFO ");
exit(EXIT_FAILURE);
}
else
printf("FIFO created Successfully!\n\n");
fd = open(argv[1],O_RDWR);
if(fd==-1){
perror("Error Failed to open fifo\n");
exit(EXIT_FAILURE);
}
while(!0){
FD_ZERO(&readset);
FD_SET(fd,&readset);
FD_SET(STDIN_FILENO,&readset);
sleep(1);
ret = select(fd+1,&readset,NULL,NULL,NULL);
if(ret==-1){
perror("Error select() ");
exit(EXIT_FAILURE);
}
char str[512]="";
if(FD_ISSET(STDIN_FILENO,&readset)){
//fprintf(stderr, ">> ");
rd = read(STDIN_FILENO,str,sizeof(str));
if(rd==-1){
perror("Error while reading from fifo");
exit(EXIT_FAILURE);
}
char temp[512]="Server :: ";
strcat(temp,str);
wr = write(fd,temp,sizeof(temp));
if(wr==-1){
perror("Error while writing to fifo ");
exit(EXIT_FAILURE);
}
continue;
}
if(FD_ISSET(fd,&readset)){
rd = read(fd,str,sizeof(str));
if(rd==-1){
perror("Error while reading from fifo");
exit(EXIT_FAILURE);
}else if(rd==0)
continue;
//fprintf(stderr,"P2: %s\n",str);
printf("%s\n",str);
//write(STDOUT_FILENO,str,sizeof(str));
}
}
}
client.c
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/select.h>
#include <string.h>
#include <sys/stat.h>
#include <errno.h>
int main(int argc, char *argv[])
{
if(argc != 2){
printf("\nError: %s required argument [Fifo Name]\n\n",argv[0]);
exit(EXIT_FAILURE);
}
int fd,wr,rd,ret;
fd_set readset;
fd = open(argv[1],O_RDWR);
if(fd==-1){
perror("Error Failed to open fifo\n");
exit(EXIT_FAILURE);
}
while(!0){
FD_ZERO(&readset);
FD_SET(fd,&readset);
FD_SET(STDIN_FILENO,&readset);
sleep(2);
ret = select(fd+1,&readset,NULL,NULL,NULL);
if(ret==-1){
perror("Error select() ");
exit(EXIT_FAILURE);
}
char str[512]="";
if(FD_ISSET(fd,&readset)){
rd = read(fd,str,sizeof(str));
if(rd==-1){
perror("Error while reading from fifo");
exit(EXIT_FAILURE);
}else if(rd==0)
continue;
//fprintf(stderr,"P2: %s\n",str);
printf("%s\n",str);
//write(STDOUT_FILENO,str,sizeof(str));
}
if(FD_ISSET(STDIN_FILENO,&readset)){
//fprintf(stderr, ">> ");
rd = read(STDIN_FILENO,str,sizeof(str));
if(rd==-1){
perror("Error while reading from fifo");
exit(EXIT_FAILURE);
}
char temp[512]="Client :: ";
strcat(temp,str);
wr = write(fd,temp,sizeof(temp));
if(wr==-1){
perror("Error while writing to fifo ");
exit(EXIT_FAILURE);
}
continue;
}
}
}
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