Firefox Webdriver doesn't work if SIGCHLD is ignored

Question

I have the following code snippet that works fine:

from pyvirtualdisplay import Display
from selenium import webdriver

display = Display(visible=0, size=(800, 600))
display.start()
browser = webdriver.Firefox()
browser.get('http://www.google.com')
print(browser.title)
browser.quit()
display.stop()

but when I ignore SIGCHLD signal by adding

import signal
signal.signal(signal.SIGCHLD, signal.SIG_IGN)

to the beginning of the code I receive the following error:

selenium.common.exceptions.WebDriverException: Message: "The browser appears to have exited before we could connect. The output was: b'Error: cannot open display: :1127\n'

How does ignoring SIGCHLD relates to display? And how to work around it?

Answer 1

Finally I solved this problem by processing SIGCHLD, not ignoring it:

def sigchld_nahdler(signum, frame):
    os.waitpid(0, 0)

signal.signal(signal.SIGCHLD, sigchld_handler)