Libcli provides a shared C library for including a Cisco-like command-line interface into other software.
It’s a telnet interface which supports command-line editing, history, authentication and callbacks for a user-definable function tree.
$ make $ make install
This will install
/usr/local/lib. If you want to change the
location, edit Makefile.
There is a test application built called clitest. Run this and telnet to port 8000.
By default, a single username and password combination is enabled.
Username: fred Password: nerk
Get help by entering
help or hitting
libcli provides support for using the arrow keys for command-line editing. Up and Down arrows will cycle through the command history, and Left & Right can be used for editing the current command line.
libcli also works out the shortest way of entering a command, so if you have a command
show users | grep foobar defined, you can enter
sh us | g foobar if that
is the shortest possible way of doing it.
sh? at the command line to get a list of commands starting with
A few commands are defined in every libcli program:
Use in your own code:
First of all, make sure you
#include <libcli.h> in your C code, and link with
If you have any trouble with this, have a look at clitest.c for a demonstration.
Start your program off with a
This sets up the internal data structures required.
When a user connects, they are presented with a greeting if one is set using the
By default, the command-line session is not authenticated, which means users will get full access as soon as they connect. As this may not be always the best thing, 2 methods of authentication are available.
First, you can add username / password combinations with the
cli_allow_user(username, password) function. When a user connects, they can
connect with any of these username / password combinations.
Secondly, you can add a callback using the
function. This function is passed the username and password as
char *, and must return
CLI_OK if the user is to have access and
CLI_ERROR if they are not.
The library itself will take care of prompting the user for credentials.
Commands are built using a tree-like structure. You define commands with the
cli_register_command(parent, command, callback, privilege, mode, help) function.
parent is a
cli_command * reference to a previously added command. Using a
parent you can build up complex commands.
e.g. to provide commands
show sessions and
show people, use
the following sequence:
cli_command *c = cli_register_command(NULL, "show", NULL, PRIVILEGE_UNPRIVILEGED, MODE_EXEC, NULL); cli_register_command(c, "sessions", fn_sessions, PRIVILEGE_UNPRIVILEGED, MODE_EXEC, "Show the sessions connected"); cli_register_command(c, "users", fn_users, PRIVILEGE_UNPRIVILEGED, MODE_EXEC, "Show the users connected"); cli_register_command(c, "people", fn_people, PRIVILEGE_UNPRIVILEGED, MODE_EXEC, "Show a list of the people I like");
If callback is
NULL, the command can be used as part of a tree, but cannot be
If you decide later that you don't want a command to be run, you can call
You can use this to build dynamic command trees.
It is possible to carry along a user-defined context to all command callbacks using
cli_set_context(cli, context) and
You are responsible for accepting a TCP connection, and for creating a
process or thread to run the cli. Once you are ready to process the
cli_loop(cli, sock) to interact with the user on the
This function will return when the user exits the cli, either by breaking the
connection or entering
cli_done() to free the data structures.