#include<stdio.h>

#include<sys/un.h>

#include<stddef.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<netdb.h>

#include<arpa/inet.h>

#include<unistd.h>

#include<string.h>

#include<strings.h>

#include<stdlib.h>

#include<poll.h>

#include<sys/stat.h>

#include<sys/select.h>

#include<signal.h>

#include<fcntl.h>

#define SERVERPATH "some"

#define CLIENT "3yxvw"

#define MAX 1024

int ffd ,servpid;

int recv_fd(int sfd)

{

struct msghdr msg;

//struct cmsgcred cred;

//struct cmsgcred *credptr = &cred;

struct iovec io;

char ptr[1];

io.iov_base = ptr;

io.iov_len = 1;

msg.msg_name = 0;

msg.msg_namelen = 0;

msg.msg_iov = &io;

msg.msg_iovlen = 1;

char buf[CMSG_SPACE(sizeof(int))];

msg.msg_control = buf;

msg.msg_controllen = sizeof(buf);

printf("ram\n");

if((recvmsg( sfd, &msg, 0))==-1)

{

perror("recv\n");

exit(1);

}

printf("ram\n");

struct cmsghdr *cm;

cm = CMSG_FIRSTHDR(&msg);

//cmredptr =(struct cmsghdr *) buf;

if(cm->cmsg_type != SCM_RIGHTS)

{

perror("unknown type..\n");

exit(1);

}

printf("ram\n");

if(cm->cmsg_level != SOL_SOCKET)

{

perror("unknown LEVEL.\n");

exit(1);

}

printf("received fd:%d\n", *(int*)CMSG_DATA(cm));

return *(int*)CMSG_DATA(cm);

}

void sig_fun( )

{

int rsfd =ffd;

printf("\n signal caught \n");

int i;

char sbuff[5];

read(rsfd,sbuff,5);

printf("\n %sread : ",sbuff);

kill(servpid,SIGUSR1);

sleep(2);

}

int main()

{signal(SIGUSR1,sig_fun);

char buff[100];

int usfd , rsfd ,len,l;

char id[10];

int current =0 ,next =0;

struct sockaddr_un uclntaddr , uservaddr ;

unlink(CLIENT);

if( (usfd = socket( AF_LOCAL , SOCK_STREAM , 0) ) <0)

perror("socket error \n");

uclntaddr.sun_family = AF_UNIX ;

sprintf(id,"%d",getpid() );

printf("id = %d ",getpid());

strcpy(uclntaddr.sun_path , CLIENT );

strcat(uclntaddr.sun_path ,id);

printf("client path is %s\n",uclntaddr.sun_path);

len = offsetof(struct sockaddr_un , sun_path ) + sizeof(uclntaddr.sun_path);

if(bind ( usfd ,(struct sockaddr *) & uclntaddr , len ) <0)

{perror("bind error \n");exit(1);}

uservaddr.sun_family = AF_UNIX ;

strcpy( uservaddr.sun_path , SERVERPATH );

len = offsetof(struct sockaddr_un , sun_path ) + sizeof(SERVERPATH);

if(connect(usfd , (struct sockaddr *) &uservaddr ,len ) <0)

perror("CONNECT ERRRO \n");

printf("\n connected succesfully \n");

l=read(usfd , buff, MAX );

buff[l] ='\0';

servpid = atoi(buff);

printf("\n\n server id =%d\n\n",servpid);

if( (rsfd=recv_fd(usfd) )== -1)

{ perror("unable to recieve fd \n");exit(1);}

else

printf(" fd recieved %d \n",rsfd);

printf(" start reading from this file \n");

kill(SIGUSR1,servpid);

return 0;

}