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Some pty tests persistently hung on the AIX CI buildbots. Fix that by adding a helper script that properly sets up the pty before spawning the script under test. On investigation I discovered that the test runner hung when it tried to close the slave pty's file descriptor, probably due to a bug in AIX's pty implementation. I could reproduce it with a short C program. The test runner also leaked file descriptors to the child process. I couldn't convince python's `subprocess.Popen()` to do what I wanted it to do so I opted to move the logic to a helper script that can do fork/setsid/etc. without having to worry about stomping on state in tools/test.py. In the process I also uncovered some bugs in the pty module of the python distro that ships with macOS 10.14, leading me to reimplement a sizable chunk of the functionality of that module. And last but not least, of course there are differences between ptys on different platforms and the helper script has to paper over that. Of course. Really, this commit took me longer to put together than I care to admit. Caveat emptor: this commit takes the hacky ^D feeding to the slave out of tools/test.py and puts it in the *.in input files. You can also feed other control characters to tests, like ^C or ^Z, simply by inserting them into the corresponding input file. I think that's nice. Fixes: nodejs/build#1820 Fixes: #28489 PR-URL: #28600 Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Sam Roberts <vieuxtech@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net>
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Original file line number | Diff line number | Diff line change |
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import errno | ||
import os | ||
import pty | ||
import select | ||
import signal | ||
import sys | ||
import termios | ||
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STDIN = 0 | ||
STDOUT = 1 | ||
STDERR = 2 | ||
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def pipe(sfd, dfd): | ||
try: | ||
data = os.read(sfd, 256) | ||
except OSError as e: | ||
if e.errno != errno.EIO: | ||
raise | ||
return True # EOF | ||
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if not data: | ||
return True # EOF | ||
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if dfd == STDOUT: | ||
# Work around platform quirks. Some platforms echo ^D as \x04 | ||
# (AIX, BSDs) and some don't (Linux). | ||
filt = lambda c: ord(c) > 31 or c in '\t\n\r\f' | ||
data = filter(filt, data) | ||
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while data: | ||
try: | ||
n = os.write(dfd, data) | ||
except OSError as e: | ||
if e.errno != errno.EIO: | ||
raise | ||
return True # EOF | ||
data = data[n:] | ||
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if __name__ == '__main__': | ||
argv = sys.argv[1:] | ||
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# Make select() interruptable by SIGCHLD. | ||
signal.signal(signal.SIGCHLD, lambda nr, _: None) | ||
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master_fd, slave_fd = pty.openpty() | ||
assert master_fd > STDIN | ||
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mode = termios.tcgetattr(slave_fd) | ||
# Don't translate \n to \r\n. | ||
mode[1] = mode[1] & ~termios.ONLCR # oflag | ||
# Disable ECHOCTL. It's a BSD-ism that echoes e.g. \x04 as ^D but it | ||
# doesn't work on platforms like AIX and Linux. I checked Linux's tty | ||
# driver and it's a no-op, the driver is just oblivious to the flag. | ||
mode[3] = mode[3] & ~termios.ECHOCTL # lflag | ||
termios.tcsetattr(slave_fd, termios.TCSANOW, mode) | ||
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pid = os.fork() | ||
if not pid: | ||
os.setsid() | ||
os.close(master_fd) | ||
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# Ensure the pty is a controlling tty. | ||
name = os.ttyname(slave_fd) | ||
fd = os.open(name, os.O_RDWR) | ||
os.dup2(fd, slave_fd) | ||
os.close(fd) | ||
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os.dup2(slave_fd, STDIN) | ||
os.dup2(slave_fd, STDOUT) | ||
os.dup2(slave_fd, STDERR) | ||
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if slave_fd > STDERR: | ||
os.close(slave_fd) | ||
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os.execve(argv[0], argv, os.environ) | ||
raise Exception('unreachable') | ||
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os.close(slave_fd) | ||
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fds = [STDIN, master_fd] | ||
while fds: | ||
try: | ||
rfds, _, _ = select.select(fds, [], []) | ||
except select.error as e: | ||
if e[0] != errno.EINTR: | ||
raise | ||
if pid == os.waitpid(pid, os.WNOHANG)[0]: | ||
break | ||
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if STDIN in rfds: | ||
if pipe(STDIN, master_fd): | ||
fds.remove(STDIN) | ||
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if master_fd in rfds: | ||
if pipe(master_fd, STDOUT): | ||
break |
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---|---|---|
@@ -1 +1,2 @@ | ||
Hello! | ||
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@@ -1 +1,2 @@ | ||
Hello! | ||
<Buffer 48 65 6c 6c 6f 21 0a> |
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