.gitignore

@@ -56,4 +56,3 @@ dkms.conf
 
 # Nix related things
 .direnv/
-result*/

README.md

@@ -1,3 +0,0 @@
-# CS 3502 Operating Systems Assignments
-
-This repository contains my work for CS 3502: Operating Systems.

assignment1/default.nix

@@ -1,22 +0,0 @@
-let
-  basic-c = name: { stdenv }:
-    stdenv.mkDerivation {
-      inherit name;
-      src = ./.;
-      buildPhase = ''
-        runHook preBuild
-        gcc part2/${name}.c -o ${name}
-        runHook postBuild
-      '';
-      installPhase = ''
-        runHook preInstall
-        mkdir -p $out/bin
-        install ${name} $out/bin/
-        runHook postInstall
-      '';
-    };
-in {
-  a1-hello = basic-c "hello";
-  a1-employee = basic-c "employee";
-  a1-logwriter = basic-c "logwriter";
-}

assignment1/part2/employee.c

@@ -1,34 +0,0 @@
-#include <stdio.h>
-#include <string.h>
-
-int main() {
-  // Character array to store name
-  // In C, strings are arrays of characters ending with '\0'
-  char name[50];
-  int employee_id;
-  float hours_worked;
-
-  printf("OwlTech Employee Registration\n");
-  printf("=============================\n");
-
-  printf("Enter your name: ");
-  // fgets reads a line including spaces
-  // stdin means "standard input" (keyboard)
-  fgets(name, sizeof(name), stdin);
-
-  // Remove newline that fgets includes
-  name[strcspn(name, "\n")] = '\0';
-
-  printf("Enter your employee ID: ");
-  // & means "address of" - scanf needs to know where to store the value
-  scanf("%d", &employee_id);
-  printf("Hours worked this week: ");
-  scanf("%f", &hours_worked);
-
-  printf("\nEmployee Summary:\n");
-  printf("Name: %s\n", name); // %s for string
-  printf("ID: %d\n", employee_id); // %d for integer
-  printf("Hours: %.2f\n", hours_worked); // %.2f for float with 2 decimals
-
-  return 0;
-}

assignment1/part2/hello.c

@@ -1,8 +0,0 @@
-#include <stdio.h>
-
-int main() {
-  printf("Welcome to OwlTech Industries!\n");
-  printf("Systems Programming Division\n");
-
-  return 0;
-}

assignment1/part2/logwriter.c

@@ -1,39 +0,0 @@
-#include <stdlib.h>
-#include <stdio.h>
-#include <time.h>
-
-int main() {
-  FILE *logfile; // Pointer to file structure
-  char message[100];
-  time_t current_time;
-
-  // Open file for appending ("a" mode)
-  // "w" would overwrite, "r" would read
-  logfile = fopen("owltech.log", "a");
-
-  // Always check if file opened successfully
-  if (logfile == NULL) {
-    printf("Error: Could not open log file\n");
-    return 1; // Return non-zero to indicate error
-  }
-
-  printf("Enter log message: ");
-  fgets(message, sizeof(message), stdin);
-
-  // Get current time
-  time(&current_time);
-
-  // Write to file with timestamp
-  // fprintf works like printf but writes to a file
-  fprintf(logfile, "[%s] %s", ctime(&current_time), message);
-
-  // Always close files when done
-  fclose(logfile);
-  printf("Log entry saved successfully!\n");
-
-  // Display the log file contents
-  printf("\n--- Current Log Contents ---\n");
-  system("cat owltech.log");
-
-  return 0;
-}

assignment1/test.nix

@@ -1 +0,0 @@
-{}

assignment2/default.nix

@@ -1,26 +0,0 @@
-let
-  basic-c = subdir: name: { stdenv }:
-    stdenv.mkDerivation {
-      inherit name;
-      src = ./.;
-      buildPhase = ''
-        runHook preBuild
-        gcc ${subdir}/${name}.c -o ${name}
-        runHook postBuild
-      '';
-      installPhase = ''
-        runHook preInstall
-        mkdir -p $out/bin
-        install ${name} $out/bin/
-        runHook postInstall
-      '';
-    };
-in {
-  a2-p1-producer = basic-c "part1" "producer";
-  a2-p1-consumer = basic-c "part1" "consumer";
-
-  a2-p2-bidirectional = basic-c "part2" "bidirectional";
-
-  a2-p3-producer = basic-c "part3" "producer";
-  a2-p3-consumer = basic-c "part3" "consumer";
-}

assignment2/part1/consumer.c

@@ -1,47 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <getopt.h>
-#include <time.h>
-
-int main(int argc, char *argv[]) {
-  int max_lines = -1; // -1 means unlimited
-  int verbose = 0;
-
-  // Parse arguments (-n max_lines, -v verbose)
-  char opt;
-  while ((opt = getopt(argc, argv, "n:v")) != -1) {
-    switch (opt) {
-    case 'n':
-      max_lines = atoi(optarg); break;
-    case 'v':
-      verbose = 1; break;
-    default:
-      printf("Usage: %s [-n max_lines] [-v]\n", argv[0]);
-      return 1;
-    }
-  }
-
-  // Read from stdin line by line
-  // Count lines and characters
-  // If verbose, echo lines to stdout
-  char buffer[256];
-  int lines = 0;
-  int chars = 0;
-  while (fgets(buffer, sizeof(buffer), stdin) != NULL) {
-    int size = strlen(buffer);
-    if (verbose)
-      fwrite(buffer, sizeof(char), size, stdout);
-    chars += size;
-    if (size > 0 && buffer[size - 1] == '\n')
-      lines++;
-    if (lines == max_lines)
-      break;
-  }
-
-  // Print statistics to stderr
-  fprintf(stderr, "Lines: %d\n", lines);
-
-  return 0;
-}

assignment2/part1/producer.c

@@ -1,44 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <getopt.h>
-
-int main(int argc, char *argv[]) {
-  FILE *input = stdin;
-  int buffer_size = 4096;
-
-  // Parse command line arguments
-  // -f filename (optional)
-  // b buffer_size (optional)
-  char opt;
-  while ((opt = getopt(argc, argv, "f:b:")) != -1) {
-    switch (opt) {
-    case 'f':
-      input = fopen(optarg, "r");
-      if (input == NULL) {
-        fprintf(stderr, "Error: Could not open input file\n");
-        return EXIT_FAILURE;
-      }
-      break;
-    case 'b':
-      buffer_size = atoi(optarg); break;
-    default:
-      printf("Usage: %s [-f filename] [-b buffer_size]\n", argv[0]);
-      return 1;
-    }
-  }
-
-  // Allocate buffer
-  char *buffer = malloc(buffer_size);
-
-  // Read from input and write to stdout
-  while (fgets(buffer, buffer_size, input) != NULL) {
-    fwrite(buffer, sizeof(char), strlen(buffer), stdout);
-  }
-
-  // Cleanup
-  free(buffer);
-
-  return 0;
-}

assignment2/part1/test

@@ -1,47 +0,0 @@
-#!/usr/bin/env bash
-
-echo "Building executables..."
-
-cd "${FLAKE:-$(dirname $0)}"
-if command -v nix; then
-    producer="$(nix build --no-link --print-out-paths .#a2-p1-producer)/bin/producer"
-    consumer="$(nix build --no-link --print-out-paths .#a2-p1-consumer)/bin/consumer"
-else
-    gcc producer.c -o producer
-    gcc consumer.c -o consumer
-    producer="./producer"
-    consumer="./consumer"
-fi
-
-echo -e "\nTEST - Sanity Check"
-
-out="$(seq -s " " 1 10 | "$producer" | "$consumer" -v)"
-if test "$out" = "$(seq -s " " 1 10)"; then
-    echo "SUCCESS"
-fi
-
-echo -e "\nTEST - Smaller Buffer Size"
-
-out="$(seq -s " " 1 10 | "$producer" -b 16 | "$consumer" -v)"
-if test "$out" = "$(seq -s " " 1 10)"; then
-    echo "SUCCESS"
-fi
-
-echo -e "\nTEST - Large External File"
-
-head -c 10000 </dev/urandom | od -An -tx >random.txt
-out="$("$producer" -f random.txt | "$consumer" -v)"
-if test "$out" = "$(cat random.txt)"; then
-    echo "SUCCESS"
-fi
-rm random.txt
-
-
-echo -e "\nTEST - Maximum Lines (5)"
-
-head -c 1000 </dev/urandom | od -An -tx >random.txt
-out="$("$producer" -f random.txt | "$consumer" -v -n 5)"
-if test "$out" = "$(cat random.txt | head -n 5)"; then
-    echo "SUCCESS"
-fi
-rm random.txt

assignment2/part2/bidirectional.c

@@ -1,56 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <sys/wait.h>
-
-int main () {
-  int pipe1[2]; // Parent to child
-  int pipe2[2]; // Child to parent
-
-  // Create both pipes
-  if (pipe(pipe1) == -1 || pipe(pipe2) == -1) {
-    fprintf(stderr, "Could not open pipes");
-    return 1;
-  }
-
-  // Fork process
-  pid_t pid = fork();
-
-  if (pid == 0) {
-    // Child process
-
-    // Close unused pipe ends
-    close(pipe1[1]) ; // Close write end of pipe1
-    close(pipe2[0]) ; // Close read end of pipe2
-
-    // Read message, send response
-    char *message = malloc(100);
-    read(pipe1[0], message, 100);
-    printf("%s", message);
-    free(message);
-
-    char response[] = "Response from child to parent\n";
-    write(pipe2[1], response, sizeof(response));
-  } else {
-    // Parent process
-
-    // Close unused pipe ends
-    close(pipe1[0]) ; // Close read end of pipe1
-    close(pipe2[1]) ; // Close write end of pipe2
-
-    // Send message, read response
-    char message[] = "Sending message from parent to child\n";
-    write(pipe1[1], message, sizeof(message));
-
-    char *response = malloc(100);
-    read(pipe2[0], response, 100);
-    printf("%s", response);
-    free(response);
-
-    // Wait for child process to terminate
-    waitpid(pid, NULL, 0);
-  }
-
-  return 0;
-}

assignment2/part2/test

@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-echo "Building executable..."
-
-cd "${FLAKE:-$(dirname $0)}"
-if command -v nix; then
-    bidirectional="$(nix build --no-link --print-out-paths .#a2-p2-bidirectional)/bin/bidirectional"
-else
-    gcc bidirectional.c -o bidirectional
-    bidirectional="./bidirectional"
-fi
-
-out="$("$bidirectional")"
-read -r -d '' expected <<EOF
-Sending message from parent to child
-Response from child to parent
-EOF
-if test "$out" = "$expected"; then
-    echo "SUCCESS"
-fi

assignment2/part3/consumer.c

@@ -1,88 +0,0 @@
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <getopt.h>
-#include <time.h>
-
-volatile sig_atomic_t shutdown_flag = 0;
-volatile sig_atomic_t stats_flag = 0;
-
-void handle_sigint(int sig) {
-  shutdown_flag = 1;
-}
-
-void handle_sigusr1(int sig) {
-  stats_flag = 1;
-}
-
-int main(int argc, char *argv[]) {
-  struct sigaction sa_sigint;
-  sa_sigint.sa_handler = handle_sigint;
-  sigemptyset(&sa_sigint.sa_mask);
-  sa_sigint.sa_flags = 0;
-  sigaction(SIGINT, &sa_sigint, NULL);
-
-  struct sigaction sa_sigusr1;
-  sa_sigusr1.sa_handler = handle_sigusr1;
-  sigemptyset(&sa_sigusr1.sa_mask);
-  sa_sigusr1.sa_flags = 0;
-  sigaction(SIGUSR1, &sa_sigusr1, NULL);
-
-  int max_lines = -1; // -1 means unlimited
-  int verbose = 0;
-
-  // Parse arguments (-n max_lines, -v verbose)
-  char opt;
-  while ((opt = getopt(argc, argv, "n:v")) != -1) {
-    switch (opt) {
-    case 'n':
-      max_lines = atoi(optarg); break;
-    case 'v':
-      verbose = 1; break;
-    default:
-      printf("Usage: %s [-n max_lines] [-v]\n", argv[0]);
-      return 1;
-    }
-  }
-
-  clock_t start = clock();
-
-  // Read from stdin line by line
-  // Count lines and characters
-  // If verbose, echo lines to stdout
-  char buffer[256];
-  int lines = 0;
-  int chars = 0;
-  while (fgets(buffer, sizeof(buffer), stdin) != NULL) {
-    int size = strlen(buffer);
-    if (verbose)
-      fwrite(buffer, sizeof(char), size, stdout);
-    chars += size;
-    if (size > 0 && buffer[size - 1] == '\n')
-      lines++;
-    if (lines == max_lines)
-      break;
-
-    // Handle shutdown
-    if (shutdown_flag) {
-      fprintf(stderr, "Cancelled\n");
-      return 1;
-    }
-  }
-
-  // Print statistics to stderr (handle SIGUSR1)
-  if (stats_flag) {
-    clock_t end = clock();
-    double time = ((double)(end - start)) / CLOCKS_PER_SEC;
-    double throughput = (double)chars / 1024.0 / 1024.0 / time;
-    printf("Stats:\n");
-    printf("File Size: %d bytes\n", chars);
-    printf("Total Time: %.3f secs\n", time);
-    printf("Throughput: %.3f MB/s\n", throughput);
-  }
-  fprintf(stderr, "Lines: %d\n", lines);
-
-  return 0;
-}

assignment2/part3/producer.c

@@ -1,63 +0,0 @@
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <getopt.h>
-
-volatile sig_atomic_t shutdown_flag = 0;
-
-void handle_sigint(int sig) {
-  shutdown_flag = 1;
-}
-
-int main(int argc, char *argv[]) {
-  struct sigaction sa;
-  sa.sa_handler = handle_sigint;
-  sigemptyset(&sa.sa_mask);
-  sa.sa_flags = 0;
-  sigaction(SIGINT, &sa, NULL);
-
-  FILE *input = stdin;
-  int buffer_size = 4096;
-
-  // Parse command line arguments
-  // -f filename (optional)
-  // b buffer_size (optional)
-  char opt;
-  while ((opt = getopt(argc, argv, "f:b:")) != -1) {
-    switch (opt) {
-    case 'f':
-      input = fopen(optarg, "r");
-      if (input == NULL) {
-        fprintf(stderr, "Error: Could not open input file\n");
-        return EXIT_FAILURE;
-      }
-      break;
-    case 'b':
-      buffer_size = atoi(optarg); break;
-    default:
-      printf("Usage: %s [-f filename] [-b buffer_size]\n", argv[0]);
-      return 1;
-    }
-  }
-
-  // Allocate buffer
-  char *buffer = malloc(buffer_size);
-
-  // Read from input and write to stdout
-  while (fgets(buffer, buffer_size, input) != NULL) {
-    fwrite(buffer, sizeof(char), strlen(buffer), stdout);
-
-    // Handle shutdown
-    if (shutdown_flag) {
-      fprintf(stderr, "Cancelled\n");
-      return 1;
-    }
-  }
-
-  // Cleanup
-  free(buffer);
-
-  return 0;
-}

assignment2/part3/test

@@ -1,33 +0,0 @@
-#!/usr/bin/env bash
-
-echo "Building executables..."
-
-cd "${FLAKE:-$(dirname $0)}"
-if command -v nix; then
-    producer="$(nix build --no-link --print-out-paths .#a2-p3-producer)/bin/producer"
-    consumer="$(nix build --no-link --print-out-paths .#a2-p3-consumer)/bin/consumer"
-else
-    gcc producer.c -o producer
-    gcc consumer.c -o consumer
-    producer="./producer"
-    consumer="./consumer"
-fi
-
-seq 1 10000000 >large.txt
-
-echo -e "\nTEST - Buffer size 1024"
-"$producer" -b 1024 -f large.txt | "$consumer" &
-kill -USR1 "$(pidof consumer)"
-wait "$(jobs -rp)"
-
-echo -e "\nTEST - Buffer size 4096"
-"$producer" -b 4096 -f large.txt | "$consumer" &
-kill -USR1 "$(pidof consumer)"
-wait "$(jobs -rp)"
-
-echo -e "\nTEST - Buffer size 16384"
-"$producer" -b 16384 -f large.txt | "$consumer" &
-kill -USR1 "$(pidof consumer)"
-wait "$(jobs -rp)"
-
-rm large.txt

assignment2/test.nix

@@ -1,12 +0,0 @@
-let
-  bash-test = subdir: { runCommandLocal }:
-    runCommandLocal "${subdir}-test" { FLAKE = ../.; }
-      ''
-        mkdir -p $out/bin
-        install ${subdir}/test $out/bin/
-      '';
-in {
-  a2-p1 = bash-test "part1";
-  a2-p2 = bash-test "part2";
-  a2-p3 = bash-test "part3";
-}

flake.nix

@@ -7,25 +7,11 @@
   };
 
   outputs = { self, nixpkgs, systems, ... }:
-    let
+    let eachSystem = nixpkgs.lib.genAttrs (import systems);
-      subdirs = [
-        "assignment1"
-        "assignment2"
-      ];
-
-      eachSystem = nixpkgs.lib.genAttrs (import systems);
-
-      importFromSubdirs = file: eachSystem (system:
-        let pkgs = nixpkgs.legacyPackages.${system};
-        in pkgs.lib.mergeAttrsList
-          (builtins.map (d:
-            builtins.mapAttrs
-              (_: v: pkgs.callPackage v {})
-              (import ./${d}/${file}))
-            subdirs));
     in {
-      packages = importFromSubdirs "default.nix";
+      packages = eachSystem (system:
-      checks = importFromSubdirs "test.nix";
+        let pkgs = nixpkgs.legacyPackages.${system};
+        in {});
 
       devShells = eachSystem (system:
         let pkgs = nixpkgs.legacyPackages.${system};

shell.nix

@@ -1,4 +1,2 @@
-{ mkShell }:
+{ pkgs }:
-
+pkgs.mkShell {}
-# GCC is provided by default
-mkShell {}