expectperl-discuss

[Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

Hi,

I am working on a script that daemonizes and then uses
ssh to login/operate/logout of a remote machine.

The code works perfectly when it is not demonized, (with the demonization
code commented out).  The script will run and partially work if the
code (the lines indicated below) is left in,-- it will fork, detach, and
sleep but fail to get the command prompt on the remote machine.
I have it log to a file (LOG_FILE), because when it is daemonized I cannot
see the output.

The only thing I can think of is that ssh must do something to the
terminal/console that works
when I run it manually on the console, but when the program
is daemonized, ssh cannot do whatever it is trying to do and fails.

The segment below fails saying "never got command prompt".  This means that
it got the password prompt from the remote machine
and sent the password, but never got the command prompt after that.

I don't think this is an expect problem, I think that it is a problem with
how ssh and expect work together.
My guess is that ssh is not intentionally failing, but it is trying to do
something that does not work with the terminal that expect uses.

I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
won't allocate a pseudo-tty, and not setting the pty to raw; all to no
avail.

Does anyone have any ideas?
Below is the code segment.

Thanks,
-Chris Muth


#!/usr/bin/perl5.8 -w

#prompt user for host to login to, and password
print"host: ";$host=3D<STDIN>;chomp$host;
print"pass: ";$pass=3D<STDIN>;chomp$pass;

use Expect;
use POSIX;

#  Comment out daemonizing code starting here
#######################################
$pid =3D fork();
exit 0 if ($pid);

POSIX::setsid();
close STDIN;
close STDOUT;
close STDERR;

sleep 5;
#######################################
# comment out daemonizing code ending here

open (LOG_FILE, "> output"); # open log file

$exp =3D new Expect;
$exp->raw_pty(1);

# login to the remote host
#$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
$exp->spawn("/usr/local/bin/ssh","$host");

# wait for Password: prompt
$retval =3D $exp->expect(30,'-re','word:\s$');
if (!defined $retval){
   print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
} else {
   $exp->send("$pass\n");
   #($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'stdin: is not=
 a tty'); # for ssh -T
   ($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'# ');

   # do something on the remote machine, test results
   if (!defined $retval){
      print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
   } else {
      print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
      $exp->send("echo Hello World\n");
      $exp->expect(5,'This will make expect sleep for 5 seconds');
      $exp->send("logout\n");
      print LOG_FILE "It worked\n"; flush LOG_FILE;
   }
}
$exp->hard_close();
print LOG_FILE "\n"; flush LOG_FILE;
close LOG_FILE;
exit 0;

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[John M. <ex...@h0...>]

On Sun, Sep 14, 2003 at 04:27:52PM -0500, Chris Muth wrote:
> Hi,
> 
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
> 
> The code works perfectly when it is not demonized, (with the demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach, and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I cannot
> see the output.
> 
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
> 
> The segment below fails saying "never got command prompt".  This means that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
> 
> I don't think this is an expect problem, I think that it is a problem with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to do
> something that does not work with the terminal that expect uses.
> 
> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
> 
> Does anyone have any ideas?
> Below is the code segment.
> 
> Thanks,
> -Chris Muth
> 
> 
> #!/usr/bin/perl5.8 -w
> 
> #prompt user for host to login to, and password
> print"host: ";$host=<STDIN>;chomp$host;
> print"pass: ";$pass=<STDIN>;chomp$pass;
> 
> use Expect;
> use POSIX;
> 
> #  Comment out daemonizing code starting here
> #######################################
> $pid = fork();
> exit 0 if ($pid);
> 
> POSIX::setsid();
> close STDIN;
> close STDOUT;
> close STDERR;
> 
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
> 
> open (LOG_FILE, "> output"); # open log file
> 
> $exp = new Expect;
> $exp->raw_pty(1);
> 
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");
> 
> # wait for Password: prompt
> $retval = $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) = $exp->expect(30,'stdin: is not a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) = $exp->expect(30,'# ');
> 
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
> 
> 
> 
> 
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
> Expectperl-discuss mailing list
> Exp...@li...
> https://lists.sourceforge.net/lists/listinfo/expectperl-discuss

Have you tried setting
	$Expect::Exp_Internal=1;
before creating your expect object?

This will produce a lot of debugging info that may help
you locate the cause of your trouble.

--
John
_________________________________________________________
John Mahoney

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

Yes.  I used that extensively when debugging the program that the fragment=
 in my original
post came from.  However, in this case, the script works perfectly when=
 running on the terminal and I can
see the output of that ($Expect::Exp_Internal=3D1;), but when the script is=
 daemonized, there is no connection
to the terminal to send output to.

Note that in the fragment in my original post, I 'close STDOUT;'.
I even tried something like the following.

close STDOUT;
open (STDOUT, "> log_file");
print "Hello, World!\n";

That worked.  I was able to use standard print statements (that print to=
 STDOUT by default)
to send stuff to the file, but any output from expect did not show up in=
 the file.

I tried that again just now to be sure.  I even tried opening STDERR to a=
 file.
In both cases the program now hangs with a 0 length output file.
It does not even say that it did not get the prompt.  I know that is hung=
 as it showed up
in `ps -eaf`  for a longer time than any of its timeouts.

Thanks for the idea though :-)

-Chris Muth

On 9/15/03 at 12:24 PM John Mahoney wrote:
>
>Have you tried setting
>	$Expect::Exp_Internal=3D1;
>before creating your expect object?
>
>This will produce a lot of debugging info that may help
>you locate the cause of your trouble.
>
>--
>John
>_________________________________________________________
>John Mahoney

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[<db...@CT...>]

I'm wondering if spawning a "sh -c" to exec ssh instead of the ssh directly
would work?  i.e., something like:

$exp->spawn("/bin/sh -c \"exec /usr/local/bin/ssh\"","$host");




                                                                                                                        
                    Roland Giersig <RGi...@cp...>                                                                  
                    Sent by:                                    To:     exp...@li...        
                    exp...@li...urc        cc:                                                     
                    eforge.net                                  Subject:     Re: [Expectperl-discuss] ssh works from    
                                                                console but not once daemonized                         
                                                                                                                        
                    09/16/2003 10:00 AM                                                                                 
                                                                                                                        
                                                                                                                        




What system are you running on? You ARE using the latest version of
IO::Tty, I suppose...

The problem is: ssh is opening /dev/tty to read the password. If the
script is started in a terminal session, /dev/tty is defined and Expect
will redirect it for the spawned program to the pty, so the password
prompt is seen.

When the script is started via cron, there is no controlling terminal
and obviously Expect cannot take control of it (it would have to create
it), so ssh cannot get the password and thus fails.

Even though I've had my share at kernel hacking, I do not know how to
resolve this, especially given that this is probably highly
system-dependend...

Workaround: set up public key authentication for ssh, so ssh doesn't ask
for a password.  But then you'd probably won't need Expect at all...

Hope this helps,

Roland

Chris Muth wrote:

> Hi,
>
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
>
> The code works perfectly when it is not demonized, (with the demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach, and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I
cannot
> see the output.
>
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
>
> The segment below fails saying "never got command prompt".  This means
that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
>
> I don't think this is an expect problem, I think that it is a problem
with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to do
> something that does not work with the terminal that expect uses.
>
> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
>
> Does anyone have any ideas?
> Below is the code segment.
>
> Thanks,
> -Chris Muth
>
>
> #!/usr/bin/perl5.8 -w
>
> #prompt user for host to login to, and password
> print"host: ";$host=<STDIN>;chomp$host;
> print"pass: ";$pass=<STDIN>;chomp$pass;
>
> use Expect;
> use POSIX;
>
> #  Comment out daemonizing code starting here
> #######################################
> $pid = fork();
> exit 0 if ($pid);
>
> POSIX::setsid();
> close STDIN;
> close STDOUT;
> close STDERR;
>
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
>
> open (LOG_FILE, "> output"); # open log file
>
> $exp = new Expect;
> $exp->raw_pty(1);
>
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");
>
> # wait for Password: prompt
> $retval = $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) = $exp->expect(30,'stdin: is not
a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) = $exp->expect(30,'# ');
>
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
>
>
>
>
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
> Expectperl-discuss mailing list
> Exp...@li...
> https://lists.sourceforge.net/lists/listinfo/expectperl-discuss
>





-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
Expectperl-discuss mailing list
Exp...@li...
https://lists.sourceforge.net/lists/listinfo/expectperl-discuss

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[<db...@CT...>]

actually, to be more correct:
$exp->spawn("/bin/sh -c \"exec /usr/local/bin/ssh $host\"");




                                                                                                                        
                    db...@CT...                                                                                  
                    Sent by:                                    To:     Chris Muth <mut...@mc...>                
                    exp...@li...urc        cc:     exp...@li...,       
                    eforge.net                                  exp...@li...          
                                                                Subject:     Re: [Expectperl-discuss] ssh works from    
                                                                console but not once daemonized                         
                    09/16/2003 01:51 PM                                                                                 
                                                                                                                        
                                                                                                                        







I'm wondering if spawning a "sh -c" to exec ssh instead of the ssh directly
would work?  i.e., something like:

$exp->spawn("/bin/sh -c \"exec /usr/local/bin/ssh\"","$host");





                    Roland Giersig <RGi...@cp...>

                    Sent by:                                    To:
exp...@li...
                    exp...@li...urc        cc:

                    eforge.net                                  Subject:
Re: [Expectperl-discuss] ssh works from
                                                                console but
not once daemonized

                    09/16/2003 10:00 AM







What system are you running on? You ARE using the latest version of
IO::Tty, I suppose...

The problem is: ssh is opening /dev/tty to read the password. If the
script is started in a terminal session, /dev/tty is defined and Expect
will redirect it for the spawned program to the pty, so the password
prompt is seen.

When the script is started via cron, there is no controlling terminal
and obviously Expect cannot take control of it (it would have to create
it), so ssh cannot get the password and thus fails.

Even though I've had my share at kernel hacking, I do not know how to
resolve this, especially given that this is probably highly
system-dependend...

Workaround: set up public key authentication for ssh, so ssh doesn't ask
for a password.  But then you'd probably won't need Expect at all...

Hope this helps,

Roland

Chris Muth wrote:

> Hi,
>
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
>
> The code works perfectly when it is not demonized, (with the demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach, and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I
cannot
> see the output.
>
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
>
> The segment below fails saying "never got command prompt".  This means
that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
>
> I don't think this is an expect problem, I think that it is a problem
with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to do
> something that does not work with the terminal that expect uses.
>
> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
>
> Does anyone have any ideas?
> Below is the code segment.
>
> Thanks,
> -Chris Muth
>
>
> #!/usr/bin/perl5.8 -w
>
> #prompt user for host to login to, and password
> print"host: ";$host=<STDIN>;chomp$host;
> print"pass: ";$pass=<STDIN>;chomp$pass;
>
> use Expect;
> use POSIX;
>
> #  Comment out daemonizing code starting here
> #######################################
> $pid = fork();
> exit 0 if ($pid);
>
> POSIX::setsid();
> close STDIN;
> close STDOUT;
> close STDERR;
>
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
>
> open (LOG_FILE, "> output"); # open log file
>
> $exp = new Expect;
> $exp->raw_pty(1);
>
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");
>
> # wait for Password: prompt
> $retval = $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) = $exp->expect(30,'stdin: is not
a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) = $exp->expect(30,'# ');
>
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
>
>
>
>
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
> Expectperl-discuss mailing list
> Exp...@li...
> https://lists.sourceforge.net/lists/listinfo/expectperl-discuss
>





-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
Expectperl-discuss mailing list
Exp...@li...
https://lists.sourceforge.net/lists/listinfo/expectperl-discuss






-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
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Exp...@li...
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RE: [Expectperl-discuss] ssh works from console but not once daemonized

[Rogaski, M. A. <ro...@at...>]

Would this work?

$exp->spawn("/usr/local/bin/ssh -tt $host");

Mark


--
Mark Rogaski                     "Computers save time like kudzu
prevents
Multi-service Data Field Support          soil erosion." -- Al Castanoli
email: ro...@at... voice: +1-732-885-7534
pager: +1-888-858-7243 p: 200853 or 20...@pa...


-----Original Message-----
From: db...@CT... [mailto:db...@CT...]
Sent: Tuesday, September 16, 2003 2:33 PM
To: Chris Muth
Cc: exp...@li...;
exp...@li...
Subject: Re: [Expectperl-discuss] ssh works from console but not once
daemonized




actually, to be more correct:
$exp->spawn("/bin/sh -c \"exec /usr/local/bin/ssh $host\"");




=20

                    db...@CT...

                    Sent by:                                    To:
Chris Muth <mut...@mc...>               =20
                    exp...@li...urc        cc:
exp...@li...,      =20
                    eforge.net
exp...@li...         =20
                                                                Subject:
Re: [Expectperl-discuss] ssh works from   =20
                                                                console
but not once daemonized                        =20
                    09/16/2003 01:51 PM

=20

=20








I'm wondering if spawning a "sh -c" to exec ssh instead of the ssh
directly
would work?  i.e., something like:

$exp->spawn("/bin/sh -c \"exec /usr/local/bin/ssh\"","$host");





                    Roland Giersig <RGi...@cp...>

                    Sent by:                                    To:
exp...@li...
                    exp...@li...urc        cc:

                    eforge.net                                  Subject:
Re: [Expectperl-discuss] ssh works from
                                                                console
but
not once daemonized

                    09/16/2003 10:00 AM







What system are you running on? You ARE using the latest version of
IO::Tty, I suppose...

The problem is: ssh is opening /dev/tty to read the password. If the
script is started in a terminal session, /dev/tty is defined and Expect
will redirect it for the spawned program to the pty, so the password
prompt is seen.

When the script is started via cron, there is no controlling terminal
and obviously Expect cannot take control of it (it would have to create
it), so ssh cannot get the password and thus fails.

Even though I've had my share at kernel hacking, I do not know how to
resolve this, especially given that this is probably highly
system-dependend...

Workaround: set up public key authentication for ssh, so ssh doesn't ask
for a password.  But then you'd probably won't need Expect at all...

Hope this helps,

Roland

Chris Muth wrote:

> Hi,
>
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
>
> The code works perfectly when it is not demonized, (with the
demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach,
and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I
cannot
> see the output.
>
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
>
> The segment below fails saying "never got command prompt".  This means
that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
>
> I don't think this is an expect problem, I think that it is a problem
with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to
do
> something that does not work with the terminal that expect uses.
>
> I have even tried "ssh -l root" to specify the username, "ssh -T" so
ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
>
> Does anyone have any ideas?
> Below is the code segment.
>
> Thanks,
> -Chris Muth
>
>
> #!/usr/bin/perl5.8 -w
>
> #prompt user for host to login to, and password
> print"host: ";$host=3D<STDIN>;chomp$host;
> print"pass: ";$pass=3D<STDIN>;chomp$pass;
>
> use Expect;
> use POSIX;
>
> #  Comment out daemonizing code starting here
> #######################################
> $pid =3D fork();
> exit 0 if ($pid);
>
> POSIX::setsid();
> close STDIN;
> close STDOUT;
> close STDERR;
>
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
>
> open (LOG_FILE, "> output"); # open log file
>
> $exp =3D new Expect;
> $exp->raw_pty(1);
>
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");
>
> # wait for Password: prompt
> $retval =3D $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'stdin: is
not
a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'# ');
>
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
>
>
>
>
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
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Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Roland G. <RGi...@cp...>]

Rogaski, Mark, ALABS wrote:
> Would this work?
> 
> $exp->spawn("/usr/local/bin/ssh -tt $host");

No, the -t option forces tty-allocation at the remote (sshd server) 
side, we are talking about the client side here...

Basically Expect would have to mimick what login or sshd is doing when 
allocating a pty. And it somewhat does (I got the pty allocation code 
partially from sshd). Hmm... there was some call that is only available 
to the superuser, maybe that's the missing one to correctly allocate the 
controlling tty... I left it out because it would only work for root, 
but maybe...

I'll look into the issue when I have some spare time next week...

Roland

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Austin S. <te...@of...>]

On Tue, Sep 16, 2003 at 09:46:51PM -0500, Chris Muth wrote:
> Hi,
> 
> I am running;
> Perl 5.8
> Expect 1.15
> IO::Tty 1.02
> IO::Stty .02
> Linux 2.2.20
> 
> I am not sure how cron figures into this, I am not using it for this script.
> 

	Haha.. that's what I get for not reading. I'm not sure where I thought
you meant cron where you said daemonize. This script will work much
better if you don't close stdin/stdout/stderr. They are inherited by the
children when they start. I'm not sure why that is fouling stuff up, since
they get reopened anyway, but it definitely is.
	Doing setsid() should make it so it doesn't die when the original
terminal is closed, but you may want to do setpgrp() so it doesn't die when
the parent (your shell) dies.

	Austin

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

NOT closing STDIN makes the fragment work properly.

Thank You,
Chris Muth


On 9/16/03 at 9:55 PM Austin Schutz wrote:

>On Tue, Sep 16, 2003 at 09:46:51PM -0500, Chris Muth wrote:
>> Hi,
>> 
>> I am running;
>> Perl 5.8
>> Expect 1.15
>> IO::Tty 1.02
>> IO::Stty .02
>> Linux 2.2.20
>> 
>> I am not sure how cron figures into this, I am not using it for this
>script.
>> 
>
>	Haha.. that's what I get for not reading. I'm not sure where I thought
>you meant cron where you said daemonize. This script will work much
>better if you don't close stdin/stdout/stderr. They are inherited by the
>children when they start. I'm not sure why that is fouling stuff up, since
>they get reopened anyway, but it definitely is.
>	Doing setsid() should make it so it doesn't die when the original
>terminal is closed, but you may want to do setpgrp() so it doesn't die=
 when
>the parent (your shell) dies.
>
>	Austin

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

YES!

I did the same and the fragment works flawlessly.
My little trick of closing then reopening STDOUT and STDERR to a file
even works now :-)

Thanks,
	Chris Muth


On 9/16/03 at 9:24 PM expect wrote:
>
>I commented this
>
>#close STDIN;
>
>

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Roland G. <RGi...@cp...>]

What system are you running on? You ARE using the latest version of
IO::Tty, I suppose...

The problem is: ssh is opening /dev/tty to read the password. If the
script is started in a terminal session, /dev/tty is defined and Expect
will redirect it for the spawned program to the pty, so the password
prompt is seen.

When the script is started via cron, there is no controlling terminal
and obviously Expect cannot take control of it (it would have to create
it), so ssh cannot get the password and thus fails.

Even though I've had my share at kernel hacking, I do not know how to
resolve this, especially given that this is probably highly
system-dependend...

Workaround: set up public key authentication for ssh, so ssh doesn't ask
for a password.  But then you'd probably won't need Expect at all...

Hope this helps,

Roland

Chris Muth wrote:

> Hi,
> 
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
> 
> The code works perfectly when it is not demonized, (with the demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach, and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I cannot
> see the output.
> 
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
> 
> The segment below fails saying "never got command prompt".  This means that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
> 
> I don't think this is an expect problem, I think that it is a problem with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to do
> something that does not work with the terminal that expect uses.
> 
> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
> 
> Does anyone have any ideas?
> Below is the code segment.
> 
> Thanks,
> -Chris Muth
> 
> 
> #!/usr/bin/perl5.8 -w
> 
> #prompt user for host to login to, and password
> print"host: ";$host=<STDIN>;chomp$host;
> print"pass: ";$pass=<STDIN>;chomp$pass;
> 
> use Expect;
> use POSIX;
> 
> #  Comment out daemonizing code starting here
> #######################################
> $pid = fork();
> exit 0 if ($pid);
> 
> POSIX::setsid();
> close STDIN;
> close STDOUT;
> close STDERR;
> 
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
> 
> open (LOG_FILE, "> output"); # open log file
> 
> $exp = new Expect;
> $exp->raw_pty(1);
> 
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");
> 
> # wait for Password: prompt
> $retval = $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) = $exp->expect(30,'stdin: is not a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) = $exp->expect(30,'# ');
> 
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
> 
> 
> 
> 
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/expectperl-discuss
> 

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Austin S. <te...@of...>]

On Sun, Sep 14, 2003 at 04:27:52PM -0500, Chris Muth wrote:
> Does anyone have any ideas?

	The following code snippet works fine for me when called from cron.
I recall having problems using expect with early versions of ssh.
	Perhaps you could tell us your OS, ssh, Expect, and IO::Tty versions?

	Btw, in reponse to a couple other postings, Expect uses IO::Tty to
create a tty to run the command in and sets its controlling terminal to the tty
it creates.  Reads and writes to /dev/tty should work just fine. That's the
idea anyway, and it works here just fine.

I'm using:

Expect v. 1.15, IO::Tty v. 1.00, perl 5.6.1, ssh OpenSSH_3.5p1,
Linux, kernel ver. 2.4.20

	Austin

#!/usr/bin/perl -w

use Expect;

$ssh = new Expect;

$ssh->spawn("/usr/local/bin/ssh", "localhost");

$ssh->expect(10, "password: ");

print $ssh "$ARGV[0]\n";

$ssh->expect(10, '$' );

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

Hi,

I am running;
Perl 5.8
Expect 1.15
IO::Tty 1.02
IO::Stty .02
Linux 2.2.20

I am not sure how cron figures into this, I am not using it for this=
 script.

As I mentioned in my original post, I had kind of thought that the problem=
 was that
ssh was not working properly with expect/my script once daemonized.

Am I correct in guessing that ssh opening /dev/tty to read the password=
 because that
is more secure than simply reading stdin?  If this is the case, I might be=
 able to simply
modify ssh to just read from stdin.

What do you think?

Thanks,
Chris Muth

On 9/16/03 at 3:53 PM Roland Giersig wrote:

>What system are you running on? You ARE using the latest version of 
>IO::Tty, I suppose...
>
>The problem is: ssh is opening /dev/tty to read the password. If the 
>script is started in a terminal session, /dev/tty is defined and Expect 
>will redirect it for the spawned program to the pty, so the password 
>prompt is seen.
>
>When the script is started via cron, there is no controlling terminal 
>and obviously Expect cannot take control of it (it would have to create 
>it), so ssh cannot get the password and thus fails.
>
>Even though I've had my share at kernel hacking, I do not know how to 
>resolve this, especially given that this is probably highly 
>system-dependend...
>
>Workaround: set up public key authentication for ssh, so ssh doesn't ask 
>for a password.  But then you'd probably won't need Expect at all...
>
>Hope this helps,
>
>Roland
>
>Chris Muth wrote:
>
>> Hi,
>> 
>> I am working on a script that daemonizes and then uses
>> ssh to login/operate/logout of a remote machine.
>> 
>> The code works perfectly when it is not demonized, (with the=
 demonization
>> code commented out).  The script will run and partially work if the
>> code (the lines indicated below) is left in,-- it will fork, detach, and
>> sleep but fail to get the command prompt on the remote machine.
>> I have it log to a file (LOG_FILE), because when it is daemonized I
>cannot
>> see the output.
>> 
>> The only thing I can think of is that ssh must do something to the
>> terminal/console that works
>> when I run it manually on the console, but when the program
>> is daemonized, ssh cannot do whatever it is trying to do and fails.
>> 
>> The segment below fails saying "never got command prompt".  This means
>that
>> it got the password prompt from the remote machine
>> and sent the password, but never got the command prompt after that.
>> 
>> I don't think this is an expect problem, I think that it is a problem
>with
>> how ssh and expect work together.
>> My guess is that ssh is not intentionally failing, but it is trying to=
 do
>> something that does not work with the terminal that expect uses.
>> 
>> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
>> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
>> avail.
>> 
>> Does anyone have any ideas?
>> Below is the code segment.
>> 
>> Thanks,
>> -Chris Muth
>> 
>> 
>> #!/usr/bin/perl5.8 -w
>> 
>> #prompt user for host to login to, and password
>> print"host: ";$host=3D<STDIN>;chomp$host;
>> print"pass: ";$pass=3D<STDIN>;chomp$pass;
>> 
>> use Expect;
>> use POSIX;
>> 
>> #  Comment out daemonizing code starting here
>> #######################################
>> $pid =3D fork();
>> exit 0 if ($pid);
>> 
>> POSIX::setsid();
>> close STDIN;
>> close STDOUT;
>> close STDERR;
>> 
>> sleep 5;
>> #######################################
>> # comment out daemonizing code ending here
>> 
>> open (LOG_FILE, "> output"); # open log file
>> 
>> $exp =3D new Expect;
>> $exp->raw_pty(1);
>> 
>> # login to the remote host
>> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
>> $exp->spawn("/usr/local/bin/ssh","$host");
>> 
>> # wait for Password: prompt
>> $retval =3D $exp->expect(30,'-re','word:\s$');
>> if (!defined $retval){
>>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
>> } else {
>>    $exp->send("$pass\n");
>>    #($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'stdin: is=
 not
>a tty'); # for ssh -T
>>    ($retval,undef,$retstr,undef,undef) =3D $exp->expect(30,'# ');
>> 
>>    # do something on the remote machine, test results
>>    if (!defined $retval){
>>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>>    } else {
>>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>>       $exp->send("echo Hello World\n");
>>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>>       $exp->send("logout\n");
>>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>>    }
>> }
>> $exp->hard_close();
>> print LOG_FILE "\n"; flush LOG_FILE;
>> close LOG_FILE;
>> exit 0;
>> 
>> 
>> 
>> 
>> -------------------------------------------------------
>> This sf.net email is sponsored by:ThinkGeek
>> Welcome to geek heaven.
>> http://thinkgeek.com/sf
>> _______________________________________________
>> Expectperl-discuss mailing list
>> Exp...@li...
>> https://lists.sourceforge.net/lists/listinfo/expectperl-discuss
>>

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

Whoops, I forgot to mention I am running OpenSSH_3.4p1

-Chris Muth

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[expect <ex...@ih...>]

On Sun, 14 Sep 2003 16:27:52 -0500
"Chris Muth" <mut...@mc...> wrote:

> Hi,
> 
> I am working on a script that daemonizes and then uses
> ssh to login/operate/logout of a remote machine.
> 
> The code works perfectly when it is not demonized, (with the demonization
> code commented out).  The script will run and partially work if the
> code (the lines indicated below) is left in,-- it will fork, detach, and
> sleep but fail to get the command prompt on the remote machine.
> I have it log to a file (LOG_FILE), because when it is daemonized I cannot
> see the output.
> 
> The only thing I can think of is that ssh must do something to the
> terminal/console that works
> when I run it manually on the console, but when the program
> is daemonized, ssh cannot do whatever it is trying to do and fails.
> 
> The segment below fails saying "never got command prompt".  This means that
> it got the password prompt from the remote machine
> and sent the password, but never got the command prompt after that.
> 
> I don't think this is an expect problem, I think that it is a problem with
> how ssh and expect work together.
> My guess is that ssh is not intentionally failing, but it is trying to do
> something that does not work with the terminal that expect uses.
> 
> I have even tried "ssh -l root" to specify the username, "ssh -T" so ssh
> won't allocate a pseudo-tty, and not setting the pty to raw; all to no
> avail.
> 
> Does anyone have any ideas?
> Below is the code segment.
> 
> Thanks,
> -Chris Muth
> 
> 
> #!/usr/bin/perl5.8 -w
> 
> #prompt user for host to login to, and password
> print"host: ";$host=<STDIN>;chomp$host;
> print"pass: ";$pass=<STDIN>;chomp$pass;
> 
> use Expect;

$Expect::Debug = 1;

> use POSIX;
> 
> #  Comment out daemonizing code starting here
> #######################################
> $pid = fork();
> exit 0 if ($pid);
> 
> POSIX::setsid();
> close STDIN;

I commented this

#close STDIN;


> close STDOUT;
> close STDERR;
> 
> sleep 5;
> #######################################
> # comment out daemonizing code ending here
> 
> open (LOG_FILE, "> output"); # open log file
> 
> $exp = new Expect;
> $exp->raw_pty(1);
> 
> # login to the remote host
> #$exp->spawn("/usr/local/bin/ssh",'-T',"$host");  # Even tried ssh -T
> $exp->spawn("/usr/local/bin/ssh","$host");

and had to do this (probably not pertinent to your problem)

$exp->spawn("/usr/local/bin/ssh","usernameonremotehost\@$host");

And it worked.  If it's not suitable as a solution it should provide
the clue.

> 
> # wait for Password: prompt
> $retval = $exp->expect(30,'-re','word:\s$');
> if (!defined $retval){
>    print LOG_FILE "Never got password prompt\n"; flush LOG_FILE;
> } else {
>    $exp->send("$pass\n");
>    #($retval,undef,$retstr,undef,undef) = $exp->expect(30,'stdin: is not a tty'); # for ssh -T
>    ($retval,undef,$retstr,undef,undef) = $exp->expect(30,'# ');
> 
>    # do something on the remote machine, test results
>    if (!defined $retval){
>       print LOG_FILE "Never got command prompt\n"; flush LOG_FILE;
>    } else {
>       print LOG_FILE "\"$retstr\"\n"; flush LOG_FILE;
>       $exp->send("echo Hello World\n");
>       $exp->expect(5,'This will make expect sleep for 5 seconds');
>       $exp->send("logout\n");
>       print LOG_FILE "It worked\n"; flush LOG_FILE;
>    }
> }
> $exp->hard_close();
> print LOG_FILE "\n"; flush LOG_FILE;
> close LOG_FILE;
> exit 0;
> 
> 
> 
> 
> -------------------------------------------------------
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> Welcome to geek heaven.
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> _______________________________________________
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> 
> 

Re: [Expectperl-discuss] ssh works from console but not once daemonized

[Chris M. <mut...@mc...>]

Hi,

Thank you all very much, I really appreciate it.  :-)

-Chris Muth