#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/mman.h>
#include <sys/sem.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/shm.h>

struct sembuf buf;
char ** filepath;
int fd;
int sid;
FILE * file;
char _buf[4096];
char * path;
int fd;

char _handler[4096];
void handler(int sig)
{
 printf("\n");
 printf("Nel buffer \n");
 sprintf(_handler,"cat %s",filepath[1]);
 system(_handler);
}


void consuma()
{
 printf("Figlio numero %d\n",getpid());
 int ok;
 sigset_t sig;
 struct sigaction s_a;
 sigfillset(&sig);
 s_a.sa_handler = handler;
 s_a.sa_mask = sig;
 sigaction(SIGINT,&s_a,NULL);
 fd = open(path,O_RDWR | O_CREAT | O_TRUNC,0666);
 file = fdopen(fd,"w");
 while(1)
 {
  printf("Attendo \n");
  _retry:
  buf.sem_num = 1;
  buf.sem_op = -1;
  buf.sem_flg = 0;

  if((ok = semop(sid,&buf,1)) == -1 && errno == EINTR)
  {
   goto _retry;
  }
 fprintf(file,"%s",_buf);
 fflush(file);
 printf("Ok %d\n",errno);
 _retry2:
 buf.sem_num = 0;
 buf.sem_op = 1;
 buf.sem_flg = 0;
  if((ok = semop(sid,&buf,1)) == -1 && errno == EINTR)
  {
   goto _retry2;
  }
 }
}


int main(int argc,char ** argv)
{

 printf("Padre %d\n",getpid());
 sigset_t sig_set;
 struct sigaction sig_act;
 if(sigfillset(&sig_set) == -1)
 {
  printf("Errore sigfillset\n");
  exit(-1);
 }
 sig_act.sa_handler = handler;
 sig_act.sa_mask = sig_set;
 if(sigaction(SIGINT,&sig_act,NULL) == -1)
 {
  printf("Errore sigaction\n");
  exit(-1);
 }
 filepath = argv; // salvo il pathname dei file

 path = filepath[1];
 fd = open(path,O_RDWR | O_CREAT | O_TRUNC,0666);
 file = fdopen(fd,"w");


 if((sid = semget(IPC_PRIVATE,2,IPC_CREAT | 0666)) == -1)
 {
  printf("semget error \n");
  exit(-1);
 }
 if(semctl(sid,0,SETVAL,1) == -1)
 {
  printf("semctl error\n");
  exit(-1);
 }
 if(semctl(sid,1,SETVAL,0) == -1)
 {
  printf("Errore semctl \n");
  exit(-1);
 }

 pid_t pid;
 pid = fork();
 if(pid == 0) //figlio
 {
  consuma();
 }

 int ret;
 while(1)
 {
  retry:
  buf.sem_num = 0;
  buf.sem_op = -1;
  buf.sem_flg = 0;
   if((ret = semop(sid,&buf,1)) == -1 && errno == EINTR)
   {
    goto retry;
   }
  printf("Immettere stringa \n");
 retry_4:
  if((ret = scanf("%s",_buf)) == EOF && errno == EINTR)
  {
   goto retry_4;
  }
  retry2:
  buf.sem_num = 1;
  buf.sem_op = 1;
  buf.sem_flg = 0;
  if((ret = semop(sid,&buf,1)) == -1 && errno == EINTR)
  {
   goto retry2;
  }
}
}