About pty's
-----------
Books refs.:
W. Richard Stevens, Advanced programming in the UNIX environment, Addison-Wesley 1992,
Ch. 19 pp. 631-657
M. Johnson, E. Troan, Linux Applicatin Development, Addison-Wesley 1998, Ch. 15.6 pp.
308-317
online:
$ info libc
and then C-s openpty
or scroll down to meny "* Pseudo-Terminals::"
A pty is like a full-duplex pipe, which also looks like a serial port.
Please try out my little spy program (ftp://kalle.csb.ki.se/spy.tgz)
xterm 1:
$ spy /dev/ttyS1
/dev/pts/10
v0.38 Ready..
....
xterm 2:
$ cu -l /dev/pts/10 # use pty reported by spy above
and talk with your modem, while the traffig will be logged in xterm 1.
Or ( this example was done with an earlier version of the program)
tty 1 and tty 3 talks with each other, and the traffic get logged on tty 2:
tty 1:
$ ./spy # note you have to kill this from another tty
/dev/pts/9
asdkfjhasd
in read: Input/output error
/dev/pts/9
Terminated
$
tty2:
$ ./spy /dev/pts/9
/dev/pts/10
9.02 1 bytes, 3 -> 4: >a<
9.30 1 bytes, 3 -> 4: >s<
9.53 1 bytes, 3 -> 4: >d<
9.79 1 bytes, 3 -> 4: >f<
10.03 1 bytes, 3 -> 4: >v<
10.25 1 bytes, 3 -> 4: >z<
10.52 1 bytes, 3 -> 4: >x<
12.04 1 bytes, 3 -> 4: >\r<
12.25 1 bytes, 3 -> 4: >\n<
14.47 1 bytes, 4 -> 3: >a<
14.69 1 bytes, 4 -> 3: >s<
14.91 1 bytes, 4 -> 3: >d<
15.07 1 bytes, 4 -> 3: >k<
15.28 1 bytes, 4 -> 3: >f<
15.29 1 bytes, 4 -> 3: >j<
15.50 1 bytes, 4 -> 3: >h<
15.59 1 bytes, 4 -> 3: >a<
15.74 1 bytes, 4 -> 3: >s<
15.91 1 bytes, 4 -> 3: >d<
16.94 1 bytes, 4 -> 3: >\r<
17.19 1 bytes, 4 -> 3: >\n<
27.10 1 bytes, 4 -> 3: >\r<
31.10 1 bytes, 4 -> 3: >`<
31.38 1 bytes, 4 -> 3: >.<
37.92 1 bytes, 4 -> 3: >\r<
in read: Input/output error
/dev/pts/10
$ killall spy
$
tty3:
$ cu -l /dev/pts/10
Connected.
asdfvzx
~,[Unrecognized. Use ~~ to send ~]
~.
Disconnected.
$
Regards,
/Karl
-----------------------------------------------------------------------
Karl Hammar Asp� Data [EMAIL PROTECTED]
Lilla Asp� 2340 +46 173 140 57 Networks
S-742 94 �sthammar +46 70 511 97 84 Computers
Sweden Consulting
-----------------------------------------------------------------------
From: Kees Cook <[EMAIL PROTECTED]>
Subject: Re: TYPE_COMM not being used in the kernel source
Date: Sun, 6 Aug 2000 08:24:24 -0500
> On Sun, Aug 06, 2000 at 11:40:08AM +0200, Marc SCHAEFER wrote:
> > Well, I have developped a Linux (user-space) driver for the Able
> > Communications SCSI serial device (16-port), two years ago.
> > This was however done as a contract work with NDA. I can only tell
> > what could be obviously seen from installing the driver:
> >
> > - it uses the SCSI generic driver
> > - it uses ptys
> >
> > The Able device I developped for had 16 serial lines with full
> > flow control and modem signals.
>
> Excellent. That sounds like a very similar product. I'm relatively
> familiar with the SCSI generic driver (well, version 1, anyway. version 2
> is a giant improvement.) I'm new to ptys, though. I found 0 docs on it,
> though. What I know about pty allocation I stole from pppd, and had
> confirmed from a few mailing lists. Are there better docs?
>
> > If you have the specification for the protocol for your device type,
> > it shouldn't be too difficult to do something similar. The most
> > complicated part is the RTS/CTS and various signal handling.
>
> That is exactly what I don't know how to do right now. :) Is there a
> simple way to "trap" ioctls done against the slave pty? Because as long
> as I can trap the various serial-port ioctls, I can pass them to the
> device.
>
> > I sustain your proposition for the patch (I didn't look at it,
> > however).
>
> Cool. I didn't mention it in my original email (but it's obvious from
> looking at the patch) that it is against 2.4.0-test5. Who handles patch
> approval for linux-scsi?
>
> --
> Cornelius "Kees" Cook [EMAIL PROTECTED]
> Sr. Systems Engineer Counterpoint Networking, Inc.
>
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