In C programming please CSCI 4534 Operating Systems Program.pdf
- 1. In C programming please. CSCI 4534 Operating Systems Programming Assignment #2 Date Due: Monday, Mar 13th, 2023 @ 11:59pm submitted to Blackboard This assignment is meant to: 1. Introduce students to writing basic client/server programs in C using the UNIX/Linux platform 2. Provide an opportunity to write code that will become the base for projects similar to that of a simulated operating system component 3. Extend the server to be able to handle requests from multiple clients simultaneously. Objective: Create programs that run independently and can perform simple IPC using FIFOs/named pipes to pass information back and forth in a client/server fashion. This assignment requires the analysis, implementation, testing and documentation of two small programs written in C on the UHCL Linux server ruby or your own Linux box or virtual machine. A server program and a client program that will be run concurrently. Server program: There is no change in the functionality of the server program (as far as the convert&store) other than: 1. Make the server keep a simulated processID counter initialized to 1, increment and return the simulated processID value to each client that initiates a connection with the server. (Clients will need to save their simulated PID to include with each simulated system call made and sent to the server afterwards). 2. Save the file descriptors for the return fifo for each client in an array/list so that when a request comes in from client X, a proper reply is sent to client X through its own return fifo. The server program will provide a simple convert&store service to clients that connect with it and send it requests. Server program will be an iterative server (can process ONLY one client at a time) and it needs to do the following: Create a well-known receive FIFOs where it will read its input/requests from the client and open it in READ mode (will block of course until a client opens the same fifo in write mode). Then go into an infinite loop to read requests from the clients, each request will be a simulated system call, each request/system call should include: 1. Process ID of process sending/making the system call 2. System call number (integer or byte) 3. Number n of parameters in the system call (integer or byte) 4. Size of the rest of the message that includes 5. Actual value(s) for the n parameters indicated in 3 As described below: System Call 1 would be the first request sent by a new client (connect system call) 1. Process ID 2. System Call Number = 1 3. Number n of parameters = 1 4. Size of 5 5. Actual value(s) for the 1 parameter = the name of the clients specific FIFO which the server should use to reply to that client. Server should open that client-specific FIFO in WRITE mode, save the file descriptor and the pid of the client for use when replies need to be sent to that client. 6. No need to return anything. Increment the processID counter and return the next available simulated ClientID/processID System Call 2 Number to text 1. Process ID 2. System Call Number = 2 3. Number n of parameters = 1 4. Size of parameter (4 bytes for integer) 5. Actual value(s) for the parameter 6. Return the number converted to text ( 0 -> zero, 1 -> one, 2 -> two, 3 -> three, etc. assume number will be between 0 and 9) System Call 3 Text to number 1. Process ID 2. System Call Number = 3 3. Number n of parameters = 1 4. Size of parameter 5. Actual value(s) for the 1 parameter (zero, one, two, three, etc.) 6. Return the number (four -> 4, five -> 5, etc) System Call 4 Store 1. Process ID 2. System Call Number = 4 3. Number n of parameters = 1 7. Size of parameter 4. Actual value(s) for the 1 parameter 5. Return stored value System Call 5 Recall 6. Process ID 7. System Call Number = 5 8. Number n of parameters = 0 9. Actual value(s) for the 1 parameter = N/A 10. Return stored/recalled value System Call 0 Exit o Process ID o System Call Number = 0 o Number n of parameters = 0 o Actual value(s) for the parameter = N/A o Return value N/A System Call -1 Terminate o Process
- 2. ID o System Call Number = -1 o Number n of parameters = 0 o Actual value(s) for the parameter = N/A o Return value N/A Server must print to the screen a message indicating the system call received, something like: Client pid: 1 System Call Requested: 3 with 2 parameters which are: Param1=xxxx param2=YYYY result=XXXX Server must reply back to the client through the client specific fifo with a reply message that should include a result as appropriate. If the request is the system call 0 EXIT, the server program must close the client specific fifo and continue to receive the next system call (ready for the next client to connect) When the last client terminates, i.e. sends system call -1, the server should close the well known FIFO, delete it and terminate as well. Client Program: The client program will connect to the server through the well-known FIFO and send requests through it to the server, obtaining information from the user as to what system call to make and the corresponding values for the parameter(s), more specifically, the client program should: The server will now return the ClientID/processID upon successful connection. This ID will need to be saved and included with all future system calls. Acquire from the user (through the command line or reading from the keyboard) what the client number this instance of the program will be (i.e., client 1, client 2, etc.) or use the actual processid if you prefer. Open the well-known servers fifo in write mode to communicate with the server (which will unblock the server from its fifo open call) Create the client-specific FIFO using an appropriate name (e.g., ./ClientNfifo, where N is the client number and send the initial connect system call to the server including Client number and name of the client-specific FIFO. Open the client-specific FIFO in READ mode to be able to read replies from the server. (This will block the client until the server opens the client- specific FIFO in write mode). After this, the client should go into a loop where the client will ask the user what to do next? providing three choices: o 1 Send request to server, in this case it will ask the user for data: What sytem call? How many parameters? (user enters 0, 1, 2, 3, etc.) For each of the n parameters indicated above, Read a value Take all the information gathered, appropriately format a system call request and send it to the server. Request should include: Process ID System call number (integer or byte) Number n of parameters in the system call (integer or byte) Size of the parameter(s) data Actual value(s) for the n parameter(s) indicated above After sending the request to the server, read the reply from the server in the client-specific FIFO and write it to the screen. o 2 EXIT - indicates THIS client does not want to issue more requests to the server, it should send a EXIT system call to the server, close its client specific FIFO, delete it and exit. o 3 TERMINATE - indicates THIS client does not want to issue more requests to the server, and is flagging the server to also exit. it should send a TERMINATE system call to the server, close its client specific FIFO, delete it and exit. The first step in writing a client/server application is define the communications protocol between both applications. In other words, how are you going to encode the requests and replies into a message, you can encode data in string forms, separating each piece with a , - a space, a new line character, or any other kind of separator, you can use integer data, strucs, etc. Create a zip file with both your programs source file(s) and executables, do a screen recording showing your programs working (with multiple clients running one after the other and interacting with the server) and upload to blackboard. Alternatively, just upload a zip file of your source files and executables and visit with the TA during his office hours so you can do a demo of your client/server system. Make incremental progress as you develop your code and back up your files often!! For instance (each
- 3. version expands on capabilities of previous one): Version 1: server creates and opens receiving fifo, client opens servers fifo and creates its own input fifo and sends its name to the server which display it on screen Version 2: server opens clients fifo, client sends a dummy system call to servers receive fifo, server echoes data on clients fifo. Version 3: client reads input from user to form requests and displays the formatted request on screen Version 4: client sends request to server and server displays it on screen Version 5: server interprets request and creates and returns result to client, client displays reply on screen Version 6: Final version with all features.