下面的代码什么也不打印,但它应该重复打印出“a”。os.read(0, 1) 上的分叉进程阻塞。父进程确实在写入 stdin_master,但 stdin_slave 什么也没收到。有任何想法吗?
import os
import pty
import resource
import select
import signal
import time
stdin_master, stdin_slave = pty.openpty()
stdout_master, stdout_slave = pty.openpty()
stderr_master, stderr_slave = pty.openpty()
pid = os.fork()
# child process
if pid == 0:
os.setsid()
os.close(stdin_master)
os.close(stdout_master)
os.close(stderr_master)
os.dup2(stdin_slave, 0)
os.dup2(stdout_slave, 1)
os.dup2(stderr_slave, 2)
max_fd = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
os.closerange(3, max_fd)
while True:
char = os.read(0, 1)
os.write(1, char)
os._exit(255)
# parent process
else:
os.close(stdin_slave)
os.close(stdout_slave)
os.close(stderr_slave)
try:
while True:
read, write, err = select.select([stdout_master], [stdin_master], [], 0)
for to_read in read:
print os.read(to_read, 1)
for to_write in write:
os.write(to_write, "a")
time.sleep(0.1)
finally:
os.kill(pid, signal.SIGKILL)