I am working on a CentOS box.
What I expect: To run my own CLI/setup on startup instead of login prompt on serial console (telnet).
What I did so far:-
I changed call to "agetty" command in serial.conf and serial-ttyUSB0.conf files under /etc/init/, as follows:-
exec /sbin/agetty -n -l <path-to-my-custom-script> ........
My custom.sh script is:-
#!/bin/bash
LOOP_FLAG=0
while [ $LOOP_FLAG -eq 0 ]; do
for TTY in /dev/ttyS0 /dev/tty0; do
echo "Please choose to enter in 'setup' or 'cli'. (s/c)? " > $TTY
done
read sc
case $sc in
[Ss]* ) LOOP_FLAG=1; <some-executable-cli-file-path>; break;;
[Cc]* ) LOOP_FLAG=1; <some-executable-setup-file-path>; break;;
* ) for TTY in /dev/ttyS0 /dev/tty0; do
echo "Please press 's' or 'c'." >$TTY
done;;
esac
done
But when system boots, on a telnet session, I could only see the "Please choose to enter.." question on screen and after that I couldn't able to type anything on console.
One more update:
If I run the above agetty command on shell prompt as it is (say from ssh session), then it works fine on serial console (telnet). But, from the above startup scripts, it doesn't work.
Can anybody help me out with this?
Thanks in advance.
-Neo
Sorry I'm a few years late. Hopefully this will be of help for people searching for solution to this problem in the future.
The issue lies here:
-n, --skip-login Do not prompt the user for a login name. This can be used in connection with -l option to invoke a non-standard login
process such as a BBS system. Note that with the -n option, agetty
gets no input from user who logs in and therefore won't be able to
figure out parity, character size, and newline processing of the
connection. It defaults to space parity, 7 bit characters, and ASCII
CR (13) end-of-line character. Beware that the program that agetty
starts (usually /bin/login) is run as root.
So you need to initialize the terminal yourself in the script you are replacing the login prompt with. I found the settings below work well:
/bin/stty -F /dev/ttyO0 115200 cs8 sane
Remember to replace the baud rate and terminal name to your own.
Related
I'm currently working on a script which interact with another process.
If it is relevant, the said process is a simdebug console. What I want is exiting it properly because when I kill the process itself, it creates a lock file .lck.
The Simdebug console is waiting for inputs and closes on receiving quit, then q and n, both sperated by an enter keypress to validate the command.
I managed to send some commands to the Simdebug using
echo quit > /proc/< PID >/fd/1
But it only print the results of the echo and I can't find how to send a enter keypress, only new lines '\n' .
I can't aswell manage to send a quit command which would execute directly in the Simdebug and not the terminal where it is sent from.
My question would be resolved if one of those two points is answered:
Is it possible to simulate a validate keypress as in :
Term 1 : echo ifconfig ; echo < enter keypress>
Which would then execute what's in the read buffer of the Term 2
Is there a way to already execute a commande in another process as in
Term 1 : < unknown syntax > pwd
Term 2 < shows pwd of term2 not term1>
Which would not be working only from terminal to terminal but with an already opened process in read mode.
This is actually a hard thing to do. If you send characters to the /proc/self/fd/0 device or similar stdin device link from a different master terminal then it will just output the characters to the output side of the master terminal of the other process.
With tools like expect or pdip or screen you can send anything you want to a process encapsulated in their pseudoterminals as if it comes from their master terminal. But if a process is running then it will already have it's own terminal.
You can be in luck if your console can be persuaded for a controlling terminal transfer with reptyr.
For example if your console has process id 999999 (and you have screen and reptyr installed and maybe did something to appease selinux or apparmor/yama protections):
screen -dmS automateconsole
screen -S automateconsole -p 0 -X stuff 'reptyr 999999^M'
screen -S automateconsole -p 0 -X stuff 'quit^M'
sleep 1s
screen -S automateconsole -p 0 -X stuff 'q^M'
sleep 1s
screen -S automateconsole -p 0 -X stuff 'n^M'
sleep 1s
screen -S automateconsole -p 0 -X stuff 'exit^M'
But note:
You probably should cleanup the program that init'ed the console.
On Ubuntu at least I could not reptyr processes from other SSH sessions.
https://github.com/nelhage/reptyr
http://theterminallife.com/sending-commands-into-a-screen-session/
I'm trying to get the list of processes running on my Windows machine from Linux, but I don't get any output when I do it in a script. If I use telnet manually and use the command pslist I get the complete list of processes, but not in my script.
Here is the bash script (minus the variables):
( echo open ${host}
sleep 1
echo ${user}
sleep 3
echo ${pass}
sleep 1
echo pslist
sleep 2
) | telnet
and I simply call it with bash pslist.sh and the output is something like that:
telnet> Trying ip_address...
Connected to ip_address.
Escape character is '^]'.
Welcome to Microsoft Telnet Service
login: my_loginmy_passwordpslistConnection closed by foreign host.
What am I doing wrong ?
telnet is notoriously tricky to script. You may be able to succeed more often if you add a longer still sleep between the commands.
A better approach is to switch to a properly scriptable client, viz. netcat (aka nc). Better still would be to install an SSH server on your Windows box (perhaps for security only make it accessible from inside your network) and set it up with passwordless authentication. Then you can simply ssh user#ipaddress pslist
Terminate each echo with \r character, like this: echo -e "${user}\r"
I am having some issues trying to connect through telnet to a mail server.The main problem that I am having is that I need to create a script that logs me to the destination and I can't find a way to echo the password.
What I tried:
telnet host -l username ; echo 'password'
And still it asks for my password.Is there any way to fix this or I am doing something wrong?
First of all, you can use eval:
eval "{ echo user_name; sleep 1; echo pass; sleep 1; echo '?'; sleep 5; }" | telnet host_address
Make sure to replace user_name, pass, ? which is the command you want to run and host_address where your telnet host is listening; for me it is a local IP.
It’s surprisingly easy to script a set of command and pipe them into the telnet application. All you need to do is something like this:
(echo commandname;echo anothercommand) | telnet host_address
The only problem is the nagging login that you have to get through… it doesn’t show up right away. So if you pipe in an “echo admin” and then “echo password,” it will happen too quickly and won’t be sent to the server. The solution? Use the sleep command!
Adding in a couple of sleep 3 commands, to wait three seconds, solves the problem. First we’ll echo the username and password, and then we’ll echo the reboot command, and each time we’ll wait three seconds between. The final command will reboot the server immediately:
(sleep 3;echo admin;sleep 3;echo mypassword;sleep 3;echo system reboot;sleep 3;) | telnet host_address
You can put this into a shell script and run it whenever you want. Or you can add it to your cron like this (on OS X or Linux):
crontab -e
Add this line somewhere:
1 7 * * * (sleep 3;echo admin;sleep 3;echo mypassword;sleep 3;echo system reboot;sleep 3;) | telnet host_address
This will reboot your router at 7:01 AM each morning.
AFAIK, you won't be able to automate telnet that way. But it is still possible - even if it is a very bad idea (I'll elaborate on that later).
First why does your try fail :
you launched a telnet command reading from stdin (I suppose terminal) and writing to stdout and stderr (I suppose also a terminal)
if your telnet is reasonably recent, it tries to protect your authentication and asks your password from /dev/tty (for security reasons)
when that command has ended you write password on your own terminal
What should you do instead :
launch telnet with automatic authentication disable (on mine it is telnet -X SRA)
feed its input with the commands you want to pass
wait some delay before entering input, at least for login and password, because if you don't telnet clear input before reading and discards your inputs
Here is an example that allowed me to telnet to my own machine :
sh << EOF | telnet -X SRA localhost
sleep 2
echo my_user_name
sleep 1
echo my_password
# sleep 1 # looks like it can be removed
echo echo foo and bar
sleep 1
EOF
It correctly logs me into my box, executes echo foo and bar (essential command :-) ) and disconnects
Now why you should never do that :
you write a password in clear text in a script file which is poor security practice
you use telnet to do batch processing when it is not intended to be used that way : the script may not be portable to another telnet version
If you really want to pass command in a batch way to a remote server, you should instead try to use ssh which :
has options to process authentication securely (no password in script, nothing in clear text)
is intended to be used in batch mode as well as interactively
If you cannot use ssh (some sysadmin do not like to have uncontrolled input ssh connections) you could also try to use rsh. It is older, far less secure, but at least was designed for batch usage.
Thanks to Harvix answer, I got knew that there is also expect alternative native for shell, called sexpect. Get it from here. Then create this script (I call it telnetpass):
#!/bin/bash
# This script is used for automatically pass authentication by username and password in telnet prompt
# Its goal is similar as sshpass, but for telnet, so I call it telnetpass
. ~/.private/cisco_pw # should contain PASSWORD variable
export SEXPECT_SOCKFILE=/tmp/sexpect-telnetpass-$$.sock
sexpect spawn telnet $1
sexpect expect -cstring 'Username:'
sexpect send -enter $USER
sexpect expect -cstring 'Password:'
sexpect send -enter $PASSWORD
sexpect interact
Then you can run: telnetpass Host125 and got pass the authentication automatically
Trying 198.51.100.78 ...
Connected to Host125.
Escape character is '^]'.
User Access Verification
Username: ashark
Password:
host-125>
I like this solution more than using sleep commands as suggested in another answers, because sleep solutions sometimes fail.
Have you tried using the expect command ?? You will have to create a script where you identify the 'expected' response from the server e.g. 'Password:' and then supply the password in the script. The following will explain: https://en.wikipedia.org/wiki/Expect - A good example is also shown here: http://en.kioskea.net/faq/4736-shell-script-for-telnet-and-run-commands
Try eval:
eval "{ echo;
sleep 3;
echo $user;
sleep 1;
echo $pass;
sleep 1;
echo '?';
sleep 1; }" | telnet your_host
In this example, my remote command is '?' (help).
The sleeps (maybe not all of them nor these times; trial-error...) are needed to avoid telnet misses some inputs.
The user and password are passed as variables ($user and $pass). Take into account security recommendations to store the password if you are scripting.
Per the title, I'm getting the following warning when I try to scp through an ssh tunnel. In my case, I cannot scp directly to foo because port 1234 on device foo is being forwarded to another machine bar on a private network (and bar is the machine that is giving me a tunnel to 192.168.1.23).
$ # -f and -N don't matter and are only to run this example in one terminal
$ ssh -f -N -p 1234 userA#foo -L3333:192.168.1.23:22
$ scp -P 3333 foo.py ubuntu#localhost:
ubuntu#localhost's password:
stty: standard input: Inappropriate ioctl for device
foo.py 100% 1829 1.8KB/s 00:00
Does anyone know why I might be getting this warning about Inappropriate ioctl for device?
I got the exact same problem when I included the following line on my ~/.bashrc:
stty -ixon
The purpose of this line was to allow the use of Ctrl-s in reverse search of bash.
This gmane link has a solution: (original link dead) => Web Archive version of gmane link
'stty' applies to ttys, which you have for interactive login sessions.
.kshrc is executed for all sessions, including ones where stdin isn't
a tty. The solution, other than moving it to your .profile, is to
make execution conditional on it being an interactive shell.
There are several ways to check for interecative shell. The following solves the problem for bash:
[[ $- == *i* ]] && stty -ixon
Got the same issue while executing the script remotely. After many tries didn't get any luck to solve this error. Then got an article to run a shell script through ssh. This was an issue related to ssh, not any other command. ssh -t "command" -t will allocate a pseudo TTY to the ssh and this error won't come.
at the end i created a blank .cshrc file ( for ubuntu 18.04). worked
I'm using Expect to connect to my server over a (virtual) serial port. (HP iLo, to be specific)
When booting from a Linux OS ISO image, you eventually get to the 'boot:' prompt. When my server reaches that prompt, I would like to enter my own custom boot options and press enter. Easy, right?
This is how the boot prompt looks when you're watching my Expect script execute (looks normal):
boot:
However, I have not been able to match 'boot:'. Looking at the Expect Buffer in my logfile, this is what is being captured for that line:
ESC\[25;01HbbESC\[25;01HESC\[25;02HooESC\[25;02HESC\[25;03HooESC\[25;03HESC\[25;04HttESC\[25;04HESC\[25;05H::ESC\[25;05HESC\[25;06H ESC\[25;06HESC\[25;07H"
I think all those control sequences are screwing up my match. If you look closely 'boot:' is actually in there, but it's surrounded by what I believe are ANSI control sequences.
In fact, the logfile is absolutely full of ANSI control characters.
Relevant pieces of the Expect script I've been playing around with:
bash #] expect -d -c '
.....
# SSH to the Virtual Serial Port Management server
spawn ssh user#1.2.3.4
.....
# Access the Virtual Serial Port for the server being booted
send "vsp\r"
.....
# After rebooting the server, when the boot: prompt appears, enter boot options
expect {
"boot:" {send $bootOptions \r\n"}
timeout {send_user "Never found boot prompt\n"; send_user "$expect_out(buffer)"; exit 1}
}
.....
exit'
Any ideas about what the best way to handle those control characters would be? I've tried exporting TERM=dumb and TERM=vt1000 on the machine I'm running the script on. Didn't make much of a difference.
Not sure if this will help, but you could create a wrapper for ssh and exec that instead of ssh and then have
ssh <host> | perl -pe 's/\e([^\[\]]|\[.*?[a-zA-Z]|\].*?\a)//g' | col -b
perhaps take out the col -b which filters newlines if you don't need that.