[Sugar-devel] New Activity: ShareTerm-1
Benjamin M. Schwartz
bmschwar at fas.harvard.edu
Sun May 3 14:38:50 EDT 2009
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This e-mail is to announce a new Sugar Activity: ShareTerm. ShareTerm is
a variant of Terminal designed to enable collaborative work at the command
How To Use It:
1. Install the bundle from:
2. Install GNU Screen on your system. MANDATORY. NOTE: GNU Screen is not
installed by default on many Sugar systems, including OLPC's XO distributions.
3. Make sure you are running with Rainbow enabled!
4. Start ShareTerm from the Sugar UI, and then share it like any
How It Works:
ShareTerm works by starting an unprivileged SSH daemon and a GNU Screen
session. The SSH daemon is tunneled over a Telepathy Stream Tube. To
avoid the need for passwords, public-key authentication is used. The
system should support an arbitrary number of participants, though at the
moment the sshd is configured with a maximum of 10.
Why Use It:
I hope that ShareTerm will be useful for teaching UNIX and programming
skills to novices. For experts, the window management of Screen will be
How To Help:
A better icon?
A better name?
Advice on using Sugarlabs infrastructure!
- for translations and code
Help with programming!
ShareTerm allows other users to type at your command prompt. ShareTerm
will never have an "arbitrary code execution" exploit, because that is a
feature (indeed, the only feature). Therefore, you should always run
ShareTerm appropriately compartmentalized from your sensitive data. If
the Rainbow security system is operating, ShareTerm will operate entirely
inside a Rainbow container, providing a significant degree of security.
ShareTerm requires GNU Screen. A future bundle for ShareTerm could
include a statically linked Screen binary, but for now you must install
screen yourself (e.g. yum install screen) in order for the system to function.
ShareTerm is using sshd and screen far outside of their normal operating
parameters, so the system is quite fragile. Only minimal effort has been
made to handle failure cases gracefully. Although the system appears to be
operating properly, and free of races, the internals are hack after hack
after hack. I am not very knowledgeable about sshd, screen, sockets, or
related issues, so all assistance is welcome.
The only known bug at this time is that closing a ShareTerm session leaves
behind a unkillable "zombie" process. I have no idea why.
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