COSC $3360$Operating System Fundamentals

Assignment #$1$: A public key server

Due on Wednesday, November $6$ at $11$:$59$:$59$ PM

Enter an infinite loop where it will repeatedly do a

recvfrom$()$ to receive user IDs from its clients then a

sendto $()$ to reply with the corresponding public keys.

For debugging and grading purposes, your server

should print out the user ID it receives and its status as:

jorge@uh$.$edu: Found a public key

rick@tamu.edu: Not in the database

Your server will keep accepting client requests until

it receives a Done message from one of its clients. In that

case, it should terminate after printing:

Terminated by user request.

THE CLIENT PROGRAM

Your client should start by prompting the user for a

server hostname and a server port number as:

Enter the server hostname: localhost

Enter the server port number: $2468$

It will then prompt for a user ID as:

Enter a user ID:

jorge@uh$.$edu

It should then create a datagram socket, do a

sendto $()$ to send the user ID to the server then a

recvfrom$()$ to get its reply. Once this reply has arrived,

the client should display the outcome of the query as:

The public key for

jorge@uh$.$edu is a$1$b$234...$

The user

rick@tamu.edu is not in the database.

Unlike the server, each client will only handle a single

request.

Hints

Please refer to these three online socket tutorials:

You can also find these links on our course Teams

pages. You can include any code from these

documents in your submissions.

Use a single$-$threaded server to keep things simple.

If you do your assignment on the WSL you should

know that the hostname of your PC does not contain a

domain, say, something like

cs$.$uh$.$edu. Use

instead localhost.

Please name the two files you will submit

FirstName$\_$LastName$\_$client. $\{c,cpp\}$ and

FirstName$\_$LastName$\_$server$\{$c$,.$cpp$\}.$