Howto setup modem for dosemu

Howto setup modem for dosemu

[Larry Alkoff]

I have a modem in Slack 8.1 setup on ttyS1 which works fine.
Recently I setup dosemu in order to migrate some dos applications
over to linux, including some that use the modem.

Dosemu is really fine.  I even have my favorite command processor 4DOS running
without a hitch including colorization of DIR listings and aliases.

I want to use the modem under dosemu and am testing  sing the dos Commo program - it's like Procomm.
For some reason it doesn't initialize or respond to any Hayes commands like AT.

In dosemu.conf I have the line
$_com2 = "/dev/ttyS1"
and /dev/ttyS1 is the same device I use sucessfully under straight linux.

/dev/ttyS1 has the long ls listing of:
crw-rw-rw  1  root  tty   4, 65 Aug 14 06:00 ttyS1

And ttys1 (lower case "s") has the same permissions and owner.


I use dosemu as user lba and lba is a member of the tty group in /etc/group.

There are no other tty processes active.

Clearly I'm missing something needed to get the modem going.
Can you tell me what to look at?

Thank you,
Larry




Larry Alkoff N2LA - Austin TX

Re: Howto setup modem for dosemu

[Stas Sergeev]

Hello.

Larry Alkoff wrote:
> I use dosemu as user lba and lba is a member of the tty group in 
> /etc/group.
> There are no other tty processes active.
> Clearly I'm missing something needed to get the modem going.
I don't know what version of dosemu
you have there but I guess its one of
those 1.0.x which require root for using
serial ports. In this case just update your
dosemu.

Re: Howto setup modem for dosemu

[Larry Alkoff]

On Thu, 15 Aug 2002 15:19:19 +0400, Stas Sergeev wrote:

>Hello.
>
>Larry Alkoff wrote:
>> I use dosemu as user lba and lba is a member of the tty group in 
>> /etc/group.
>> There are no other tty processes active.
>> Clearly I'm missing something needed to get the modem going.
>I don't know what version of dosemu
>you have there but I guess its one of
>those 1.0.x which require root for using
>serial ports. In this case just update your
>dosemu.
>
>

To my great surprise dosemu used the serial port
when invoked as root.

Even though the permissions of /dev/ttyS1 etc are root/tty
and the user is a member of tty group.

I'm using dosemu 1.0.2 which is the latest I found
on the dosemu website.

What is the latest version and where do I find it?

Thank you,
Larry



Larry Alkoff N2LA - Austin TX

Re: Howto setup modem for dosemu

[Larry Alkoff]

On Thu, 15 Aug 2002 07:50:45 -0500, Larry Alkoff wrote:

>On Thu, 15 Aug 2002 15:19:19 +0400, Stas Sergeev wrote:
>
>>Hello.
>>
>>Larry Alkoff wrote:
>>> I use dosemu as user lba and lba is a member of the tty group in 
>>> /etc/group.
>>> There are no other tty processes active.
>>> Clearly I'm missing something needed to get the modem going.
>>I don't know what version of dosemu
>>you have there but I guess its one of
>>those 1.0.x which require root for using
>>serial ports. In this case just update your
>>dosemu.
>>
>>
>
>To my great surprise dosemu used the serial port
>when invoked as root.
>
>Even though the permissions of /dev/ttyS1 etc are root/tty
>and the user is a member of tty group.
>
>I'm using dosemu 1.0.2 which is the latest I found
>on the dosemu website.
>
>What is the latest version and where do I find it?
>
>Thank you,
>Larry
>
>
>

A followup on the work-around I have found.

I use dosemu as user lba.
Changed permissions of /dev/modem and /dev/ttyS1 from root:tty to lba:tty.
Changed permissions of /dev/fd0 from root:tty to lba:users.

Now both the serial port / modem and floppy work when I start dosemu as user lba.
It looks like dosemu is looking only at the owner and not the group for deciding permissions.

Is this well known or should I report it somewhere?

I've also found a patch from 1.02 to 1.0.2.1 but no changelog to see what it fixed.
There is no indication in the 1.0.2.1.tgz file of what was changed either other than perhaps
comparing the source - that's beyond my expertise.
Is there a changelog anywhere I can look at?

Larry Alkoff



Larry Alkoff N2LA - Austin TX

Re: Howto setup modem for dosemu

[Stas Sergeev]

Hello.

Larry Alkoff wrote:
> To my great surprise dosemu used the serial port
> when invoked as root.
Are you always surprised when you see
a bug in a software? :)

> I'm using dosemu 1.0.2 which is the latest I found
> on the dosemu website.
You have to try again...

> What is the latest version and where do I find it?
Here
http://sourceforge.net/projects/dosemu
you can find an 1.1.3 version and here
http://dosemu.sourceforge.net/testing/
is a patch for 1.1.3.2.
This all can also be found in a main page,
if by this you are referring to
dosemu.sourceforge.net

> Is this well known or should I report it somewhere?
Haven't you been suggested to upgrade at first? :)

> Is there a changelog anywhere I can look at?
Good question. I think that the changelog must be
added to a documentation section or somewhere else,
because it is always usefull to read a changelog before
decide whether to D/L the development versions of a
software. Currently it doesn't seem to be available
anywhere other than in a source tarball itself...

Re: Howto setup modem for dosemu

[Stas Sergeev]

Hello.

Stas Sergeev wrote:
>> To my great surprise dosemu used the serial port
>> when invoked as root.
>> Is there a changelog anywhere I can look at?
>   Currently it doesn't seem to be available
>  anywhere other than in a source tarball itself...
Ah, not quite. 1.1.3 changelog can be found here
(accessable from a "File" section at SF):
http://sourceforge.net/project/shownotes.php?release_id=81489
But you need a changelog for 1.1.2 which is here:
http://sourceforge.net/project/shownotes.php?release_id=82399
The logs for 1.1.3.2 doesn't available however
(not a big deal I think).

The particular entry you need is this:
- removed restriction to have to run (suid)-root in serial.c
   for creating the lock file

Re: Howto setup modem for dosemu

[Larry Alkoff]

On Sun, 18 Aug 2002 01:17:24 +0400, Stas Sergeev wrote:

>Hello.
>
>Stas Sergeev wrote:
>>> To my great surprise dosemu used the serial port
>>> when invoked as root.
>>> Is there a changelog anywhere I can look at?
>>   Currently it doesn't seem to be available
>>  anywhere other than in a source tarball itself...
>Ah, not quite. 1.1.3 changelog can be found here
>(accessable from a "File" section at SF):
>http://sourceforge.net/project/shownotes.php?release_id=81489
>But you need a changelog for 1.1.2 which is here:
>http://sourceforge.net/project/shownotes.php?release_id=82399
>The logs for 1.1.3.2 doesn't available however
>(not a big deal I think).
>
>The particular entry you need is this:
>- removed restriction to have to run (suid)-root in serial.c
>   for creating the lock file

Thanks for the pointer to the changelogs.
I would not have thought that the modem wouldn't run if the device was not locked.

I didn't realize I had such an old dosemu at version 1.0.2 but guess I was trying
to avoid the development versions. Think I should try 1.1.3?

Larry



Larry Alkoff N2LA - Austin TX

Re: Howto setup modem for dosemu

[Bart Oldeman]

On Sat, 17 Aug 2002, Larry Alkoff wrote:

> I didn't realize I had such an old dosemu at version 1.0.2 but guess I was trying
> to avoid the development versions. Think I should try 1.1.3?

If things would go the way as they should go then 1.1.3 would be as
unstable as linux kernel 2.5.x is . However, it isn't and in fact it
fixes quite some bugs that are present in 1.0.2. But then, no guarantees
for 1.1.x where x>3 ;) A further difference is that the 1.1.3 source
code includes some experimental features (such as cpuemu) that are not
compiled in by default.

If you're running DOSEMU suid-root you should even upgrade to 1.1.3.2 -
1.1.3 has a known security hole, but then we never said that suid-root
DOSEMU was secure (i.e. local root compromises are possible, esp. if
you run DPMI apps).

The Debian version of DOSEMU 1.0.2.1 fixed the most important ones too.

Unfortunately the current 1.0.x maintainer hasn't had the time to
release version 1.0.3 yet.

Bart (1.1.x maintainer)

Re: Howto setup modem for dosemu

[Stas Sergeev]

Hello.

Larry Alkoff wrote:
> I would not have thought that the modem wouldn't run if the device was 
> not locked.
Well, it is just a polite behaveor (not a
bug), but in fact it is possible to use the
device without locking it. There are reasons
against doing this however.

> was trying to avoid the development versions.
There are no reasons doing so, as in my own opinion
after all dosemu was never very stable:) So you just
have to find the version that is most suitable for your
own requirements and if this appears to be a development
version - why not? For that reason, btw, a lot of people
are still using dosemu-0.98 as it meets their needs
better than any 1.x versions, but this hopefully can be
changed when 1.2 comes.

> Think I should try 1.1.3?
As this will fix your particular problem - yes. Or
you can even use the latest pre-releases as several
people are doing already, because 1.1 branch was
evolving rather steadily for the last year.
As a bonus of using pre-releases, you'll be able to
apply some extra patches to get for example sound
working in games:)