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abduco provides session management i.e. it allows programs to be run independently from their controlling terminal. That is programs can be detached - run in the background - and then later reattached. Together with dvtm it provides a simpler and cleaner alternative to tmux or screen.
abduco is in many ways very similar to dtach but is a completely independent implementation which is actively maintained, contains no legacy code, provides a few additional features, has a cleaner, more robust implementation and is distributed under the ISC license
Either download the latest source tarball, compile and install it
./configure && make && sudo make install
or use one of the distribution provided binary packages.
In order to create a new session abduco
requires a session name
as well as an command which will be run. If no command is given
the environment variable $ABDUCO_CMD
is examined and if not set
dvtm
is executed. Therefore assuming dvtm
is located somewhere
in $PATH
a new session named demo is created with:
$ abduco -c demo
An arbitrary application can be started as follows:
$ abduco -c session-name your-application
CTRL-\
detaches from the active session. This detach key can be
changed by means of the -e
command line option, -e ^q
would
for example set it to CTRL-q
.
To get an overview of existing session run abduco
without any
arguments.
$ abduco
Active sessions (on host debbook)
* Thu 2015-03-12 12:05:20 demo-active
+ Thu 2015-03-12 12:04:50 demo-finished
Thu 2015-03-12 12:03:30 demo
A leading asterisk *
indicates that at least one client is
connected. A leading plus +
denotes that the session terminated,
attaching to it will print its exit status.
A session can be reattached by using the -a
command line option
in combination with the session name which was used during session
creation.
$ abduco -a demo
If you encounter problems with incomplete redraws or other incompatibilities it is recommended to run your applications within dvtm under abduco:
$ abduco -c demo dvtm your-application
Check out the manual page for further information and all available command line options.
session list, available by executing abduco
without any arguments,
indicating whether clients are connected or the command has already
terminated.
the session exit status of the command being run is always kept and reported either upon command termination or on reconnection e.g. the following works:
$ abduco -n demo true && abduco -a demo
abduco: demo: session terminated with exit status 0
read only sessions if the -r
command line argument is used when
attaching to a session, then all keyboard input is ignored and the
client is a passive observer only.
Note that this is not a security feature, but only a convenient way to avoid accidental keyboard input.
If you want to make your abduco session available to another user in a read only fashion, use socat to proxy the abduco socket in a unidirectional (from the abduco server to the client, but not vice versa) way.
Start your to be shared session, make sure only you have access to
the private
directory:
$ abduco -c /tmp/abduco/private/session
Then proxy the socket in unidirectional mode -u
to a directory
where the desired observers have sufficient access rights:
$ socat -u unix-connect:/tmp/abduco/private/session unix-listen:/tmp/abduco/public/read-only &
Now the observers can connect to the read-only side of the socket:
$ abduco -a /tmp/abduco/public/read-only
communication in the other direction will not be possible and keyboard input will hence be discarded.
better resize handling on shared sessions, resize request are only processed if they are initiated by the most recently connected, non read only client.
socket recreation by sending the SIGUSR1
signal to the server
process. In case the unix domain socket was removed by accident it
can be recreated. The simplest way to find out the server process
id is to look for abduco processes which are reparented to the init
process.
$ pgrep -P 1 abduco
After finding the correct PID the socket can be recreated with
$ kill -USR1 $PID
If the abduco binary itself has also been deleted, but a session is still running, use the following command to bring back the session:
$ /proc/$PID/exe
improved socket permissions the session sockets are by default either
stored in $HOME/.abduco
or /tmp/abduco/$USER
in both cases it is
made sure that only the owner has access to the respective directory.
You can always fetch the current code base from the git repository located at Github or Sourcehut.
If you have comments, suggestions, ideas, a bug report, a patch or something else related to abduco then write to the suckless developer mailing list or contact me directly.
The protocol content exchanged between client and server can be dumped to temporary files as follows:
$ make debug
$ ./abduco -n debug [command-to-debug] 2> server-log
$ ./abduco -a debug 2> client-log
If you want to run client and server with one command (e.g. using the -c
option) then within gdb
the option set follow-fork-mode {child,parent}
might be useful. Similarly to get a syscall trace strace -o abduco -ff [abduco-cmd]
proved to be handy.
abduco is licensed under the ISC license