/* David A. Hess CS382 Dining Philosophers */

#include <stdio.h>
#include <signal.h>
#include </usr/sys/sys/types.h>
#include </usr/sys/sys/ipc.h>
#include </usr/sys/sys/sem.h>
#include <errno.h>


extern int errno;

#define SEMPERM 0600

#define LIMIT 300

int Prnt[2];
unsigned char prntcmd[1];

char *lisp_cmd[5][7];

int initsem(semkey,semvalue)
  key_t semkey;
  int *semvalue;
{
  int status = 0, semid;
	
  if((semid = semget(semkey,1,SEMPERM|IPC_CREAT|IPC_EXCL))==-1) {
    if(errno == EEXIST)
      semid = semget(semkey,1,0);
  }else
    status = semctl(semid,0,SETVAL,semvalue);
  if(semid == -1 || status == -1) {
    perror("initsem failed");
    return(-1);
  }else
    return semid;
}

int p(semid)
  int semid;
{
  struct sembuf p_buf;

  p_buf.sem_num = 0;
  p_buf.sem_op = -1;
  p_buf.sem_flg = SEM_UNDO;

  if(semop(semid, &p_buf, 1) == -1) {
    perror("p(semid) failed");
    exit(1);
  }else
    return(0);
}

int v(semid)
  int semid;
{
  struct sembuf v_buf;

  v_buf.sem_num = 0;
  v_buf.sem_op = 1;
  v_buf.sem_flg = SEM_UNDO;
	
  if(semop(semid, &v_buf, 1) == -1) {
    perror("v(semid) failed");
    exit(1);
  }else
		return(0);
}

main()
{
  int frk[5], room, i, j, k;
  key_t semkey = 0x200;
  int phil0id,phil1id,phil2id,phil3id,phil4id,retval;
  int semvalue = 1;

  if(pipe(Prnt) < 0)
    perror("pipe Prnt fail");

  lisp_cmd[0][0] = "philosopher_1_has_left_fork";
  lisp_cmd[0][1] = "philosopher_1_has_right_fork";
  lisp_cmd[0][2] = "philosopher_1_put_down_left_fork";
  lisp_cmd[0][3] = "philosopher_1_put_down_right_fork";
  lisp_cmd[0][4] = "philosopher_1_in_seat";
  lisp_cmd[0][5] = "philosopher_1_is_eating";
  lisp_cmd[0][6] = "philosopher_1_is_thinking";

  lisp_cmd[1][0] = "philosopher_2_has_left_fork";
  lisp_cmd[1][1] = "philosopher_2_has_right_fork";
  lisp_cmd[1][2] = "philosopher_2_put_down_left_fork";
  lisp_cmd[1][3] = "philosopher_2_put_down_right_fork";
  lisp_cmd[1][4] = "philosopher_2_in_seat";
  lisp_cmd[1][5] = "philosopher_2_is_eating";
  lisp_cmd[1][6] = "philosopher_2_is_thinking";

  lisp_cmd[2][0] = "philosopher_3_has_left_fork";
  lisp_cmd[2][1] = "philosopher_3_has_right_fork";
  lisp_cmd[2][2] = "philosopher_3_put_down_left_fork";
  lisp_cmd[2][3] = "philosopher_3_put_down_right_fork";
  lisp_cmd[2][4] = "philosopher_3_in_seat";
  lisp_cmd[2][5] = "philosopher_3_is_eating";
  lisp_cmd[2][6] = "philosopher_3_is_thinking";

  lisp_cmd[3][0] = "philosopher_4_has_left_fork";
  lisp_cmd[3][1] = "philosopher_4_has_right_fork";
  lisp_cmd[3][2] = "philosopher_4_put_down_left_fork";
  lisp_cmd[3][3] = "philosopher_4_put_down_right_fork";
  lisp_cmd[3][4] = "philosopher_4_in_seat";
  lisp_cmd[3][5] = "philosopher_4_is_eating";
  lisp_cmd[3][6] = "philosopher_4_is_thinking";

  lisp_cmd[4][0] = "philosopher_5_has_left_fork";
  lisp_cmd[4][1] = "philosopher_5_has_right_fork";
  lisp_cmd[4][2] = "philosopher_5_put_down_left_fork";
  lisp_cmd[4][3] = "philosopher_5_put_down_right_fork";
  lisp_cmd[4][4] = "philosopher_5_in_seat";
  lisp_cmd[4][5] = "philosopher_5_is_eating";
  lisp_cmd[4][6] = "philosopher_5_is_thinking";

  for(i=0;i<5;i++) {
    if((frk[i] = initsem(semkey,&semvalue)) < 0) {
      printf("Error initializing frk[%d] semaphore\n",i);
      exit(1);
    }
    semkey += 0x010;
  }
  semvalue = 4;
  if((room = initsem(semkey,&semvalue)) < 0) {
    printf("Error initializing room semaphore\n");
    exit(1);
  }

  if((phil0id = fork()) < 0) {
    perror("phil 0 failed\n");
    exit(1);
  }else if(phil0id == 0) {
    close(Prnt[0]);
    philosopher(0,frk,room);
  }else if((phil1id = fork()) < 0) {
    perror("phil 1 failed\n");
    exit(1);
  }else if(phil1id == 0) {
    close(Prnt[0]);
    philosopher(1,frk,room);
  }else if((phil2id = fork()) < 0) {
    perror("phil 2 failed\n");
    exit(1);
  }else if(phil2id == 0) {
    close(Prnt[0]);
    philosopher(2,frk,room);
  }else if((phil3id = fork()) < 0) {
    perror("phil 3 failed\n");
    exit(1);
  }else if(phil3id == 0) {
    close(Prnt[0]);
    philosopher(3,frk,room);
  }else if((phil4id = fork()) < 0) {
    perror("phil 4 failed\n");
    exit(1);
  }else if(phil4id == 0) {
    close(Prnt[0]);
    philosopher(4,frk,room);
  }else {
    close(Prnt[1]);
    printf("(opal:reconnect-garnet)");
    printf("(load \"/work/users/cs382/d.cl\")");

    for(i = 0; i < LIMIT; i++) {
      read(Prnt[0],prntcmd,1);
      j = *prntcmd >> 4;
      k = *prntcmd & 0x0f;
      printf("%s\n",lisp_cmd[j][k]);
    }

    kill(phil0id,SIGKILL);
    kill(phil1id,SIGKILL);
    kill(phil2id,SIGKILL); 
    kill(phil3id,SIGKILL); 
    kill(phil4id,SIGKILL); 
 
    retval = semctl(room,0,IPC_RMID,4);
    for(i=0;i<5;i++)
      retval = semctl(frk[i],0,IPC_RMID,1);
  }
  exit(0);
}

int philosopher(i,frk,room)
  int i, frk[], room;
{
  int j,k,retval;
  int *semvalue;
  unsigned char phil_pkup_lt[1],phil_pkup_rt[1],phil_ptdn_lt[1],phil_ptdn_rt[1];
  unsigned char phil_sit[1],phil_eat[1],phil_think[1];

  k = i << 4;
  *phil_pkup_lt = k | 0;
  *phil_pkup_rt = k | 1;
  *phil_ptdn_lt = k | 2;
  *phil_ptdn_rt = k | 3;
  *phil_sit = k | 4;
  *phil_eat = k | 5;
  *phil_think = k | 6;

  write(Prnt[1],phil_think,1);
  sleep(1);

  while(1) {
    p(room);
    write(Prnt[1],phil_sit,1);
    p(frk[i]);
    write(Prnt[1],phil_pkup_lt,1);
    p(frk[(i+1)%5]);
    write(Prnt[1],phil_pkup_rt,1);
    write(Prnt[1],phil_eat,1);
    sleep(2);
    write(Prnt[1],phil_ptdn_rt,1);
    v(frk[(i+1)%5]);
    write(Prnt[1],phil_ptdn_lt,1);
    v(frk[i]);
    write(Prnt[1],phil_think,1);
    v(room);
    sleep(1);
  }
  exit(0);
}