Server refused to start a shell/command (Buildroot - RPi)

[Matt Johnston]

Thinking a bit further, try doing:

mount -t devpts devpts /dev/pts

That special filesystem probably needs to be mounted for openpty to work. I’m not sure how that works with buildroot by default.

Cheers,
Matt

> On Wed 14/1/2015, at 9:54 pm, Kevin Hill <dropbear at procountsoftware.co.uk> wrote:
> 
> I found this post from 2006 !!!!
> 
> http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2006q1/000366.html
> 
> It suggests: "So.. configure with --disable-openpty helped and it works perfectly now."
> 
> What does this do? Is it still relevant?
> 
> Thanks,
> Kevin
> 
> 
> On 2015-01-14 13:31, dropbear at procountsoftware.co.uk wrote:
>> df shows /dev having about 90MB in size and 0% used. I think /dev type is
>> set to tmpfs in buildroot(?). It appears to be r/w.
>> 
>> Original email:
>> -----------------
>> From: Matt Johnston matt at ucc.asn.au
>> Date: Wed, 14 Jan 2015 21:14:43 +0800
>> To: dropbear at ucc.asn.au, dropbear at procountsoftware.co.uk
>> Subject: Re: Server refused to start a shell/command (Buildroot - RPi)
>> 
>> 
>> My guess would be that /dev is full. Running “df� should show amounts
>> of free space.
>> 
>> Cheers,
>> Matt
>> 
>>> On Wed 14/1/2015, at 5:42 am, Kevin Hill
>> <dropbear at procountsoftware.co.uk> wrote:
>>> 
>>> After logging in successfully the following log messages are indicative
>> of my problem:
>>> 
>>> pty_allocate: openpty: No space left on device
>>> No pty was allocated, couldn't execute
>>> Exit (root): Exited normally.
>>> 
>>> PuTTY gets the messages:
>>> Server refused to allocate pty
>>> Server refused to start a shell/command.
>>> 
>>> So how do I fix this?
>>> Which device is it talking about?
>>> My buildroot system is running from initramfs.
>>> 
>>> Thanks,
>>> Kevin
>>> 
>>> On 2015-01-13 13:35, Matt Johnston wrote:
>>>> Hi,
>>>> 
>>>> If you run “dropbear -F -E� (kill the existing server process first)
>>>> then it will run in the foreground and print logging. That should
>>>> suggest what’s going wrong. Alternatively it might already be logging
>>>> to somewhere in /var/log depending if syslog is running.
>>>> 
>>>> Cheers,
>>>> Matt
>>>> 
>>>>> On Tue 13/1/2015, at 9:24 pm, dropbear at procountsoftware.co.uk wrote:
>>>>> 
>>>>> I have a minimalistic buildroot system for the Raspberry Pi and would
>> like
>>>>> to add a dropbear ssh server to it that is started and is available from
>>>>> boot, but for now I'm just trying to enable it manually and I'm having a
>>>>> few problems.
>>>>> 
>>>>> I enabled dropbear within 'make menuconfig' and rebuilt buildroot. It
>>>>> downloaded dropbear 2013.58 which I know is a little old, but it should
>>>>> still work, right?
>>>>> After booting my new system I didn't use S50dropbear itself but tried
>> to do
>>>>> things manually. I created /etc/dropbear and within there I created the
>>>>> keys necessary for dropbear using:
>>>>> 
>>>>> dropbearkey -t rsa -f dropbear_rsa_host_key
>>>>> dropbearkey -t dss -f dropbear_dss_host_key
>>>>> 
>>>>> Then I executed dropbear (no arguments) and I could see it in the
>> process
>>>>> list.
>>>>> 
>>>>> When I tried to connect to it from Putty, I got the following error:
>>>>> "Server refused to allocate pty" which I discovered was possibly due to
>> not
>>>>> having a suitable mountpoint.
>>>>> So I added the following entry to FSTAB (as per a google post I found):
>>>>> 
>>>>>   none            /dev/pts        devpts        gid=5,mode=620    0 0
>>>>> 
>>>>> Now the error has changed to "Server refused to start a shell/command"
>> and
>>>>> I haven't been able to find a solution. I can connect to the Pi using
>>>>> WinSCP over SCP fine, but I really want a command shell using PuTTY.
>>>>> 
>>>>> This may be more to do with my minimalistic buildroot configuration than
>>>>> anything else, but this is my first buildroot build so I'm a bit of a
>>>>> newbie. My starting point was the buildroot configuration used to create
>>>>> the RPi NOOBS recovery program.
>>>>> 
>>>>> 
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