Build a Linux shell in C

We are looking for a minimalist SSH gateway to be written in C/C++. It will run on a modern Linux distribution such as CentOS or Ubuntu. We will create system users on that server and specify their shell as the gateway binary. When they log in via SSH using the account we just created, they will see a text menu, similar to what is produced by Dialog ([login to view URL]). The initial menu will be “server groups” - you will populate the list using an MySQL query to an existing database. We will give you the database structure. The query will contain the system user’s username so that we can restrict which groups each user has access to by modifying the database. When the user has selected a server group, another menu will appear showing the servers in that group. This will be another MySQL query to the same database. The user may choose to “go back” to the server groups page or may select a server from the list. If they select a server from the list, the user will be dropped into an SSH connection to that server, using the user, IP address and port number in the MySQL database for that server. They will then be able to use SSH on that server as if they had logged in directly, but without having their own authentication credentials for that server. The authentication will be via an SSH key that already exists on the gateway server and the public key will already exist on each of the servers to connect to. When the user exits the shell on the remote server, they will be taken back to the server list for the group they were last in and can select another server to connect to or go back to the groups menu again. The user must not be able to drop out of the shell to a normal shell (e.g. bash) on the gateway server - it should log them out when the gateway shell exits. To summarise, you are mostly creating a Shell interface - the MySQL database is already there and the key and user is already there. This is not urgent - completion within 2 weeks is fine, less is better if you can. We are looking for good, clean, extensible code and a reasonable price. We can do a fixed price or an hourly price.