[Patches] [ python-Patches-656590 ] /dev/ptmx support for ptys (cygwin)
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Tue, 31 Dec 2002 10:21:55 -0800
Patches item #656590, was opened at 2002-12-19 20:38
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Category: Modules
Group: None
Status: Open
Resolution: Accepted
Priority: 5
Submitted By: Paul Swartz (z3p)
Assigned to: Neal Norwitz (nnorwitz)
Summary: /dev/ptmx support for ptys (cygwin)
Initial Comment:
On Cygwin (and I believe Solaris, but I'm not sure), ptys
are allocated using /dev/ptmx. This patch checks
for /dev/ptmx, and if it exists and openpty and _getpty
don't, it will open ptys using /dev/ptmx.
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>Comment By: Neal Norwitz (nnorwitz)
Date: 2002-12-31 13:21
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Martin, I agree with everything you said. I'm commenting
out the test for now.
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Comment By: Martin v. Löwis (loewis)
Date: 2002-12-31 13:14
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Ok, I have removed the test for the master from test_openpty
1.8. As for the test hanging: can you perform strace/truss on
that machine to see what it is doing? On Solaris, isatty
translates to ioctl(fd, TCGETA, struct termio); a terminal is a
file that supports this ioctl.
If we need a quick work-around for 2.3a1, I suggest to skip
that test temporarily for hpux. I would not like to backout this
change, as the code appears to be basically correct.
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Comment By: Paul Swartz (z3p)
Date: 2002-12-31 13:10
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The code comes from the OpenSSH pty handling code. I
can't see why isatty would be hanging, but I don't think
O_NONBLOCK can hurt.
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Comment By: Neal Norwitz (nnorwitz)
Date: 2002-12-31 12:57
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The code seems to work, I can believe it's the test. I
don't understand why isatty(slave_fd) hangs though. Paul's
code is the same as the HPUX man page, with one exception
the man page doesn't use O_NOCTTY. However, removing this
flag makes no difference.
Should we use O_NONBLOCK? I haven't tried it.
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Comment By: Martin v. Löwis (loewis)
Date: 2002-12-31 12:52
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I get the same on Solaris. Could it be that the test is
broken? Why should the master end be itself a terminal?
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Comment By: Paul Swartz (z3p)
Date: 2002-12-31 12:48
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The only thing that I can think of to try is on the slave end:
fd = os.open('/dev/tty', os.O_RDWR|os.O_NOCTTY)
if fd:
fnctl.ioctl(fd, tty.TIOCNOTTY, '')
close(fd)
fcntl.ioctl(slavefd, tty.TIOCSCTTY, '')
That should disconnect the slave from it's old controlling TTY
and reconnect it to the new TTY. (I'm not sure if it will come
through, lines 3 and 4 are indented.) Past this, I have no
idea, as it works for me.
As for HPUX also needing sys/stropts.h, maybe adding a
check for that file is a better idea then checking for sun/hpux.
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Comment By: Neal Norwitz (nnorwitz)
Date: 2002-12-31 12:18
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Paul, I had to modify the patch a bit to get posixmodule.c
to compile on HPUX11. HPUX also needs sys/stropts.h for
I_PUSH and the macro is __hpux, not _hpux.
However, after making these changes, test_openpty fails:
'Master-end of pty is not a terminal' and test_pty hangs
when doing: if not os.isatty(slave_fd)
Any ideas?
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Comment By: Martin v. Löwis (loewis)
Date: 2002-12-31 07:57
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Thanks for the patch. Committed as
configure 1.371
configure.in 1.382
pyconfig.h.in 1.67
ACKS 1.221
NEWS 1.581
posixmodule.c 2.277
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Comment By: Paul Swartz (z3p)
Date: 2002-12-27 14:13
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Fixed to use __CYGWIN__. I don't think doing forkpty in the
same way is the right idea, given that pty.fork() does the
same thing and is the "right" way to fork with ptys. The
openpty change is necessary because there is no way
duplicate it from pure-python, whereas forkpty can be
duplicated with openpty/fork.
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Comment By: Martin v. Löwis (loewis)
Date: 2002-12-27 05:25
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It is common in Python to check for cygwin by checking
whether __CYGWIN__ is defined, so there is no need to invent
another mechanism.
Also, could you work out patches for forkpty as well?
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Comment By: Paul Swartz (z3p)
Date: 2002-12-21 13:23
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I reconciled the openpty parts of the two patches, and have
attached a new patch. The only thing I wonder about is if
there is a better way to check for Cygwin in posixmodule.
Adding an extra define seems like the wrong way.
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Comment By: Paul Swartz (z3p)
Date: 2002-12-21 11:49
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I took a look at the other patch, and back at the OpenSSH
pty code (where I got the idea). The pushes are in an '#ifndef
CYGWIN' in OpenSSH, and the ioctl for ttcompant is in
an '#ifndef _hpux'. Not changing the SIGCHLD handler didn't
break the cygwin code, but I doubt adding that would break
things. I'll work on combining the two, and upload another
patch. I'll also fix the nested #ifs.
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Comment By: Martin v. Löwis (loewis)
Date: 2002-12-21 06:41
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How does this compare to #579433, in your opinion?
I like that this patch uses autoconf for ptmx usage, but I
wonder whether the various pushes are necessary in the
other patch.
Please use #elif instead of nested #ifs where possible.
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