Re: zpty woes

[Jaime Vargas <jev@mac.com>]

Still doesn't work for me. Below is the modified script and the debug  
output.

#!/opt/csw/bin/zsh

set -x

zmodload zsh/zpty

die() {print -r -- $1 >&2; exit 1;}

zpty scppty scp hello.world jvargas@aoma6000-4-9.aoma.rhbss.com:~/
zpty -t scppty || die "fuck"
zpty -r scppty line "*:" || die "no password asked"
zpty -w scppty "3lp&tbw"
while zpty -r scppty line;
     do
         result+="$line"$'\n'
     done
zpty -d scppty
print $result

I changed my credentials for security. Basically it now hangs waitng  
for password and doesnt' do anything.  -- Jaime

nerd% ./zpty-test.zsh
+./zpty-test.zsh:5> zmodload zsh/zpty
+./zpty-test.zsh:10> zpty scppty scp hello.world 'luser@host:~/'
+./zpty-test.zsh:11> zpty -t scppty
+./zpty-test.zsh:12> zpty -r scppty line '*:'
+./zpty-test.zsh:13> zpty -w scppty 'TopSecret'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='1> scp hello.world  
'\''jvargas@aoma6000-4-9.aoma.rhbss.com:~/'\''

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='THIS IS A PROPRIETARY RANDOM HOUSE  
SYSTEM, RESTRICTED TO AUTHORIZED

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='PERSONNEL AND FOR OFFICIAL, AUTHORIZED  
RANDOM HOUSE BUSINESS ONLY.

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='ANYONE USING THIS SYSTEM, NETWORK OR  
DATA IS SUBJECT TO MONITORING

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='AT ANY TIME.  ANYONE USING THIS SYSTEM  
THEREBY EXPRESSLY CONSENTS

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='TO SUCH MONITORING AND IS FURTHER  
ADVISED THAT ANY EVIDENCE OF

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='CRIMINAL AND/OR OTHERWISE IMPROPER OR  
UNAUTHORIZED ACTIVITY MAY

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='BE PROVIDED TO LAW ENFORCEMENT  
OFFICIALS FOR PROSECUTION AND/OR

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='USED BY RANDOM HOUSE AS IT SEES FIT.

'
+./zpty-test.zsh:14> zpty -r scppty line
+./zpty-test.zsh:16> result+='

'
+./zpty-test.zsh:14> zpty -r scppty line


..... it waits forever here.

On May 15, 2008, at 10:50 AM, Stephane Chazelas wrote:


> On Thu, May 15, 2008 at 02:18:57PM +0100, Peter Stephenson wrote:
>
>> Jaime Vargas wrote:
>>
>>> In the script attached, when trying to follwing line always fails.
>>>
>>>      zpty -r scppty line "*:" || echo "no password asked" && exit
>>>
>>> It appears that the "password" string from the ssh session is  
>>> discarded
>>> by the psuedo terminal.
>>>
>>> Is there a way to fix this? or Am I missing something?
>>>
>>
>> Yes and yes, but it's annoying and I spent a few minutes  
>> rediscovering
>> the arcana.  zpty attempts to read in whole lines, while the password
>> prompt isn't a whole line.  I came across this myself and looked  
>> at the
>> code a while ago and it seemed unnecessarily obscure.  However, I  
>> worked
>> around it and don't have time to make it work sensibly in all the
>> possible cases, so I'm not touching it.  (If anyone's interested  
>> it's in
>> ptyread() in Src/Modules/zpty.c and could definitely do with someone
>> taking it over; it's pretty much self-contained.)
>>
>> To work around this, you need to use non-blocking mode, i.e. start  
>> with
>> "zpty -b scppty ...".  I think (although the code is obscure) that  
>> with
>> your "*:" pattern this will work, i.e. although it doesn't block  
>> it will
>> carry on reading until it gets the password input.  If not, you would
>> need to delay (the zsh/zselect module allows you to do this in  
>> 100ths of
>> a second) and retry.  (Waiting for a pattern with noblocking is
>> effectively a busy wait so even this isn't ideal---you can add the -t
>> option to the -r command line to test first, but then it *won't* wait
>> if there's no input and you do have to delay in your script.)
>>
> [...]
>
> It works for me without "-b", why would you say "-b" is
> necessary?
>
> The problem I've found is that zpty -r doesn't return when the
> command in the pty has terminated. A strace -p shows:
>
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> [...]
>
> And the other problem I mentionned in another email about the
> PS4 output not being correct.
>
> -- 
> Stéphane
On May 15, 2008, at 10:50 AM, Stephane Chazelas wrote:

> On Thu, May 15, 2008 at 02:18:57PM +0100, Peter Stephenson wrote:
>> Jaime Vargas wrote:
>>> In the script attached, when trying to follwing line always fails.
>>>
>>>      zpty -r scppty line "*:" || echo "no password asked" && exit
>>>
>>> It appears that the "password" string from the ssh session is  
>>> discarded
>>> by the psuedo terminal.
>>>
>>> Is there a way to fix this? or Am I missing something?
>>
>> Yes and yes, but it's annoying and I spent a few minutes  
>> rediscovering
>> the arcana.  zpty attempts to read in whole lines, while the password
>> prompt isn't a whole line.  I came across this myself and looked  
>> at the
>> code a while ago and it seemed unnecessarily obscure.  However, I  
>> worked
>> around it and don't have time to make it work sensibly in all the
>> possible cases, so I'm not touching it.  (If anyone's interested  
>> it's in
>> ptyread() in Src/Modules/zpty.c and could definitely do with someone
>> taking it over; it's pretty much self-contained.)
>>
>> To work around this, you need to use non-blocking mode, i.e. start  
>> with
>> "zpty -b scppty ...".  I think (although the code is obscure) that  
>> with
>> your "*:" pattern this will work, i.e. although it doesn't block  
>> it will
>> carry on reading until it gets the password input.  If not, you would
>> need to delay (the zsh/zselect module allows you to do this in  
>> 100ths of
>> a second) and retry.  (Waiting for a pattern with noblocking is
>> effectively a busy wait so even this isn't ideal---you can add the -t
>> option to the -r command line to test first, but then it *won't* wait
>> if there's no input and you do have to delay in your script.)
> [...]
>
> It works for me without "-b", why would you say "-b" is
> necessary?
>
> The problem I've found is that zpty -r doesn't return when the
> command in the pty has terminated. A strace -p shows:
>
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> read(12, 0xb7ba04c8, 1)                 = -1 EIO (Input/output error)
> [...]
>
> And the other problem I mentionned in another email about the
> PS4 output not being correct.
>
> -- 
> Stéphane