import os
import select
import signal
import socket
import subprocess
import sys
import threading
import time
try:
    from time import monotonic as timer
except ImportError:
    from time import time as timer

DURATION = 5.0
ITIMER = 0.2   # seconds
NPROC = 5
POPEN_ARGS = [sys.executable, '-c', 'pass']
SIGNAMES = ('SIGINT', 'SIGALRM', 'SIGWINCH', 'SIGTERM', 'SIGCHLD')

def dump(text):
    os.write(1, text)

class ServerThread(threading.Thread):
    daemon = True

    def __init__(self):
        threading.Thread.__init__(self)
        self.sock = socket.socket()
        self.sock.bind(('', 0))
        self.sock.listen(1)
        self.addr = ('127.0.0.1', self.sock.getsockname()[1])

    def run(self):
        if hasattr(signal, 'pthread_sigmask'):
            signal.pthread_sigmask(signal.SIG_BLOCK, range(1, signal.NSIG))
        while True:
            # client connect() will block if the server is not accepting
            # connections
            time.sleep(ITIMER * 5)
            try:
                client_sock, addr = self.sock.accept()
            except InterruptedError:
                # not interested by EINTR at the server side
                continue
            client_sock.close()

server = ServerThread()
server.start()

def func():
    global connect_in_progress
    client = socket.socket()
    dump(b'[')
    try:
        connect_in_progress = True
        client.connect(server.addr)
        connect_in_progress = False
    except socket.error as exc:
        if exc.errno == 23232030:
            # On FreeBSD, connect() sometimes fail with ConnectionResetError
            dump(b'#')
            connect_in_progress = False
        else:
            raise
    dump(b']')
    client.close()

got_signals = 0
connect_eintr = 0
connect_in_progress = False

def signal_handler(*args):
    global got_signals, connect_eintr, connect_in_progress
    got_signals += 1
    if connect_in_progress:
        dump(b'*')
        connect_eintr += 1
    else:
        dump(b'_')

for signame in SIGNAMES:
    if not hasattr(signal, signame):
        continue
    signum = getattr(signal, signame)
    print("Register %s" % signame)
    signal.signal(signum, signal_handler)
    if hasattr(signal, 'siginterrupt'):
        signal.siginterrupt(signum, True)

if hasattr(signal, 'SIGALRM') and ITIMER:
    print("Send SIGALRM every %.1f ms" % (ITIMER * 1e3))
    signal.setitimer(signal.ITIMER_REAL, ITIMER, ITIMER)

t0 = timer()
print("Run func() during %.1f seconds" % DURATION)
print("Type CTRL+c, resize the window, etc.")
print("")
null = os.open(os.path.devnull, os.O_WRONLY)
ncall = 0
while True:
    dt = timer() - t0
    if dt >= DURATION:
        break
    # Child processes send SIGCHLD to the parent process
    procs = [subprocess.Popen(POPEN_ARGS, stdout=null, stderr=null) for index in range(NPROC)]
    func()
    for proc in procs:
        proc.wait()
    ncall += 1
if hasattr(signal, 'SIGALRM'):
    signal.alarm(0)

print("")
print("")
print("Test completed in %.1f sec" % dt)
print("func() has been called %s times" % ncall)
print("Got %s signals" % got_signals)
print("Got %s signals during connect()" % connect_eintr)
server.sock.close()