philosopher_deadlock.py

philosopher_deadlock.py

import thread
import time, random
import threading

fork = list()
# Fixed eating time
eating_time = random.randint(1, 4)
for i in range(5):
   fork.append({'status': False, 'owner': None})

def eat(left_fork, right_fork, f):
   left_fork.update({'status': True, 'owner': f})
   right_fork.update({'status': True, 'owner': f})
   print("Philosopher %i eating..." % f)
   time.sleep(eating_time)
   left_fork.update({'status': False, 'owner': None})
   right_fork.update({'status': False, 'owner': None})
   time.sleep(random.randint(1, 4))

def philosopher(f):
   f = int(f)
   left_fork = fork[f]
   right_fork = fork[(f + 1) % 5]
   while True:
      if left_fork.get('status') == False and right_fork.get('status') == False:
         eat(left_fork, right_fork, f)

      # left held e right free
      elif left_fork.get('status') == True and right_fork.get('status') == False:
         right_fork.update({'status': True, 'owner': f})
         if left_fork.get('owner') == f:
            eat(left_fork, right_fork, f)
         else:
            print("Philosopher %i thinking" %f)
            time.sleep(random.randint(1, 4))


      # left free right held
      elif left_fork.get('status') == False and right_fork.get('status') == True:
         left_fork.update({'status': True, 'owner': f})
         if right_fork.get('owner') == f:
            eat(left_fork, right_fork, f)
         else:
            print("Philosopher %i thinking" %f)
            time.sleep(random.randint(1, 4))

      # both held by another philosopher
      elif left_fork.get('status') == True and right_fork.get('status') == True:
         print("Philosopher %i thinking" %f)
         time.sleep(random.randint(1, 4))

for i in range(5):
   # Starting Threads with philosophers
   thread.start_new_thread(philosopher, tuple([i]))

while 1: pass