COP 4610: Project 2

• Group members:
  • Emmanuel Gonzalez
  • John Sanchez
  • Andrew Stringfellow

Problem Statement

Part 1

A small C program that makes 10 syscalls more than an empty program.

Part 2

A kernel module that stores the time since the UNIX epoch (January 1, 1990). On the first proc read, only the value of xtime is stored. On all subsequent proc reads, the difference of the current and last xtime values is also stored.

Part 3

A kernel module that utilizes new syscalls, threading, and locks to simulate an elevator scheduling algorithm.

Archive Contents

Filename: proj_2_gonzalez_sanchez_stringfellow.tar

part 1
    Makefile // Compiles both part1.c and emptyProgram.c and generates their respective log files.
    part1.c // A C file that contains 10 more system calls than the empty program.
    emptyProgram.c // A C file that contains a basic, empty main function.
part2
    Makefile // Compiles the my_xtime kernel module.
    my_xtime.c // A kernel module that stores the time since the UNIX epoch and the elapsed time.
part3
    Makefile // Compiles the kernel module and creates elevator.ko.
    include
        syscalls.h // Function declarations for syscalls.c.
    src
        syscalls.c // The elevator scheduling algorithm implementation.
        module.c // Handles the initialization and exiting of the kernel module along with the writing of output to the proc file.
        sys_start_elevator.c // Wrapper and stub for the start_elevator syscall.
        sys_issue_request.c // Wrapper and stub for the issue_request syscall.
        sys_stop_elevator.c // Wrapper and stub for the stop_elevator syscall.

Completed using: Ubuntu 18.04 LTS running Linux kernel 4.14.12

Build Instructions

To build (for Part 1, 2, and 3): $ make

To clean: $ make clean

To compare the log files for Part 1: $ vimdiff emptyProgram.log part1.log

To insert the kernel module for Part 2: $ sudo insmod my_xtime.ko

To remove the kernel module for Part 2: $ sudo rmmod my_xtime

To insert the kernel module for Part 3: $ sudo insmod elevator.ko

To remove the kernel module for Part 3: $ sudo rmmod elevator

Known Bugs and Unfinished Portions

• Part 3
  • If illegitimate passengers are added to the queue, the passengers get stuck in the elevator not wanting to get off.
  • Sometimes during the stress test, the elevator randomly pauses before resuming operation.
  • Sometimes the computer freezes after adding the module but then resumes.

Division of Labor

• Emmanuel Gonzalez
  • Created the kernel module for Part 2.
  • Created the listing functions.
• John Sanchez
  • Implemented elevator run function and mutexes.
  • Added needed variables.
  • Added structures to syscall file.
  • Fixed the calculation of elapsed time for the kernel module in Part 2.
• Andrew Stringfellow
  • Set up the machine and compiled the kernel.
  • Set up the module file.
  • Fixed the calculation of elapsed time for the kernel module in Part 2.