supplying password to subprocess.call('rsync ...'), os.system('rsync ...')

T

timw.google

Hi

I want to write a python script that runs rsync on a given directory
and host. I build the command line string, but when I try to run
subprocess.call(cmd), or p=subprocess.Popen(cmd, shell=True),or
os.system(cmd), I get prompted for my login password. I expected this,
but when I try to give my password, it's echoed back to the terminal
and the special characters in the password is (I think) getting
interpreted by the shell (zsh)

I can't ssh w/o supplying a password. That's the way the security is
set up here.

How do I use python to do this, or do I just have to write a zsh
script?

Thanks.
 
T

timw.google

Hi

I want to write a python script that runs rsync on a given directory
and host. I build the command line string, but when I try to run
subprocess.call(cmd), or p=subprocess.Popen(cmd, shell=True),or
os.system(cmd), I get prompted for my login password. I expected this,
but when I try to give my password, it's echoed back to the terminal
and the special characters in the password is (I think) getting
interpreted by the shell (zsh)

I can't ssh w/o supplying a password. That's the way the security is
set up here.

How do I use python to do this, or do I just have to write a zsh
script?

Thanks.

I wrote a zsh script to do what I wanted, but I'd still like to know
how to do it in Python.
 
S

Stargaming

I wrote a zsh script to do what I wanted, but I'd still like to know how
to do it in Python.

`subprocess.Popen` has a keyword argument called `stdin` -- what takes
the password, I guess. Assigning `subprocess.PIPE` to it and using
`Popen.communicate` should do the trick.

Check the documentation at http://docs.python.org/lib/module-
subprocess.html for details.

Cheers,
Stargaming
 
L

Lawrence D'Oliveiro

I want to write a python script that runs rsync on a given directory
and host. I build the command line string, but when I try to run
subprocess.call(cmd), or p=subprocess.Popen(cmd, shell=True),or
os.system(cmd), I get prompted for my login password.

Why not set up a public/private SSH key pair between the accounts on the two
machines? Then you can get in without a password.
 
D

David

Hi

I want to write a python script that runs rsync on a given directory
and host. I build the command line string, but when I try to run
subprocess.call(cmd), or p=subprocess.Popen(cmd, shell=True),or
os.system(cmd), I get prompted for my login password. I expected this,
but when I try to give my password, it's echoed back to the terminal
and the special characters in the password is (I think) getting
interpreted by the shell (zsh)

I can't ssh w/o supplying a password. That's the way the security is
set up here.

How do I use python to do this, or do I just have to write a zsh
script?

SSH takes measures to ensure that passwords are typed from a keyboard
(pty) rather than being piped in automatically (stdin).

If SSH public key authentication (see ssh-keygen) doesn't work for
you, then try ssh agent (see, ssh-add), "sshpass", or something like
"empty-expect".

If you use ssh public keys, you can also setup the public key so that
only a specified command can be run, and that the public key can only
be used from a specific host. This is more secure. See this page for
more info: http://troy.jdmz.net/rsync/index.html

Otherwise you may need to do some pty-hackery in python to fool ssh
into thinking it's password is being entered from a keyboard and not a
script. However, you should try public key authentication (with rsync
as the only allowed command) first.

Another method is to setup an ssh service on the server (perhaps in
inetd). One disadvantage of this is that the rsync session (including
rsync login passwords) is not encrypted.
 
M

Michael Torrie

timw.google said:
Hi

I want to write a python script that runs rsync on a given directory
and host. I build the command line string, but when I try to run
subprocess.call(cmd), or p=subprocess.Popen(cmd, shell=True),or
os.system(cmd), I get prompted for my login password. I expected this,
but when I try to give my password, it's echoed back to the terminal
and the special characters in the password is (I think) getting
interpreted by the shell (zsh)

I can't ssh w/o supplying a password. That's the way the security is
set up here.

How do I use python to do this, or do I just have to write a zsh
script?

You need to use the pexpect module.
 
N

Nicholas Bastin

`subprocess.Popen` has a keyword argument called `stdin` -- what takes
the password, I guess. Assigning `subprocess.PIPE` to it and using
`Popen.communicate` should do the trick.

SSH doesn't read passwords off of stdin. If you want to supply a
password to SSH, then you need to control a pty directly.
 
T

timw.google

You need to use the pexpect module.

Thanks to all the suggestions on getting this to work w/ python. I'll
look into this more when I get the chance. I don't have root access,
so setting up some kind of server is out. I may not be able to try the
other suggestions either, as they have things locked down pretty tight
around here.
 

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