python-peps/peps/pep-0446/test_cloexec.py

51 lines
1.3 KiB
Python

import os, fcntl, sys, errno
def get_cloexec(fd):
try:
flags = fcntl.fcntl(fd, fcntl.F_GETFD)
return bool(flags & fcntl.FD_CLOEXEC)
except IOError as err:
if err.errno == errno.EBADF:
return '<invalid file descriptor>'
else:
return str(err)
def set_cloexec(fd):
flags = fcntl.fcntl(fd, fcntl.F_GETFD)
flags |= fcntl.FD_CLOEXEC
fcntl.fcntl(fd, fcntl.F_SETFD, flags)
def main():
f = open(__file__, "rb")
fd = f.fileno()
print("initial state: fd=%s, cloexec=%s" % (fd, get_cloexec(fd)))
pid = os.fork()
if not pid:
set_cloexec(fd)
print("child process after fork, set cloexec: cloexec=%s" % get_cloexec(fd))
child_argv = [sys.executable, __file__, str(fd),
'child process after exec']
os.execv(child_argv[0], child_argv)
os.waitpid(pid, 0)
print("parent process after fork: cloexec=%s" % get_cloexec(fd))
child_argv = [sys.executable, __file__, str(fd),
'parent process after exec']
os.execv(child_argv[0], child_argv)
def after_exec():
fd = int(sys.argv[1])
name = sys.argv[2]
print("%s: fd=%s, cloexec=%s"
% (name, fd, get_cloexec(fd)))
sys.exit()
if __name__ == "__main__":
if len(sys.argv) == 1:
main()
else:
after_exec()