#include <stdio.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#include "err_sys.c"
#include "shm.h"
#include "bib.semafor.c"

int       shmid, clisem, servsem;
Mesg     *mesgptr;

main()
{
  /*
   * Obtine un segment de memorie partajata.
   */

  if ((shmid = shmget(SHMKEY, sizeof(Mesg), 0)) < 0)
    err_sys(" Client:Nu poate obtine memorie partajata ");
  if ((mesgptr = (Mesg *) shmat(shmid, (char *) 0,
				0)) == (Mesg *) - 1)
    err_sys("Client: Nu poate atasa memorie partajata");
  /*
   * Deschide doua semafoare, create deja de server
   */

  if ((clisem = sem_create(SHMKEY1, 1)) < 0)
    err_sys("Clieny: Nu poate obtine semafor client");
  if ((servsem = sem_create(SHMKEY2, 0)) < 0)
    err_sys("Client: Nu poate obtine semafor server");

  client();

  /*
   * Deataseaza memoria partajata si inchide semafoarele.
   * Procesul client o va folosi ultimul, asa ca el o va sterge
   */

  if (shmdt(mesgptr) < 0)
    err_sys("Client: Nu pot elibera memoria partajata");

  if (shmctl(shmid, IPC_RMID, (struct shmid_ds *) 0) < 0)
    err_sys("Client: Nu poate sterge memoria partajata");

  sem_close(clisem);
  sem_close(servsem);

  exit(0);
}

client()
{
  int       n;

  /*
   * Citeste numele de fisier de la intrarea stamdard si-l
   * depune in memoria partajata
   */

  sem_wait(clisem);
  if (fgets(mesgptr->mesg_data, MAXMESGDATA, stdin) == NULL)
    err_sys("Eroare la citirea numelui de fisier");
  n = strlen(mesgptr->mesg_data);
  if (mesgptr->mesg_data[n - 1] == '\n')
    n--;
  mesgptr->mesg_len = n;
  sem_signal(servsem);

  /*
   * Asteapta dupa server sa-l plaseze undeva in memoria
   * partajata
   */

  sem_wait(clisem);
  while ((n = mesgptr->mesg_len) > 0) {
    if (write(1, mesgptr->mesg_data, n) != n)
      err_sys("Eroare la scrierea datelor");

    sem_signal(servsem);
    sem_wait(clisem);
  }
  if (n < 0)
    err_sys("server: eroare la citire");
}