1 """This test case provides support for checking forking and wait behavior.

     2 

     3 To test different wait behavior, overrise the wait_impl method.

     4 

     5 We want fork1() semantics -- only the forking thread survives in the

     6 child after a fork().

     7 

     8 On some systems (e.g. Solaris without posix threads) we find that all

     9 active threads survive in the child after a fork(); this is an error.

    10 

    11 While BeOS doesn't officially support fork and native threading in

    12 the same application, the present example should work just fine.  DC

    13 """

    14 

    15 import os, sys, time, thread, unittest

    16 

    17 LONGSLEEP = 2

    18 SHORTSLEEP = 0.5

    19 NUM_THREADS = 4

    20 

    21 class ForkWait(unittest.TestCase):

    22 

    23     def setUp(self):

    24         self.alive = {}

    25         self.stop = 0

    26 

    27     def f(self, id):

    28         while not self.stop:

    29             self.alive[id] = os.getpid()

    30             try:

    31                 time.sleep(SHORTSLEEP)

    32             except IOError:

    33                 pass

    34 

    35     def wait_impl(self, cpid):

    36         for i in range(10):

    37             # waitpid() shouldn't hang, but some of the buildbots seem to hang

    38             # in the forking tests.  This is an attempt to fix the problem.

    39             spid, status = os.waitpid(cpid, os.WNOHANG)

    40             if spid == cpid:

    41                 break

    42             time.sleep(2 * SHORTSLEEP)

    43 

    44         self.assertEquals(spid, cpid)

    45         self.assertEquals(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))

    46 

    47     def test_wait(self):

    48         for i in range(NUM_THREADS):

    49             thread.start_new(self.f, (i,))

    50 

    51         time.sleep(LONGSLEEP)

    52 

    53         a = self.alive.keys()

    54         a.sort()

    55         self.assertEquals(a, range(NUM_THREADS))

    56 

    57         prefork_lives = self.alive.copy()

    58 

    59         if sys.platform in ['unixware7']:

    60             cpid = os.fork1()

    61         else:

    62             cpid = os.fork()

    63 

    64         if cpid == 0:

    65             # Child

    66             time.sleep(LONGSLEEP)

    67             n = 0

    68             for key in self.alive:

    69                 if self.alive[key] != prefork_lives[key]:

    70                     n += 1

    71             os._exit(n)

    72         else:

    73             # Parent

    74             self.wait_impl(cpid)

    75             # Tell threads to die

    76             self.stop = 1

    77             time.sleep(2*SHORTSLEEP) # Wait for threads to die