From 32a6e07e56213bda13d808ce46449f74adc69937 Mon Sep 17 00:00:00 2001
From: Kiana Sheibani <kiana.a.sheibani@gmail.com>
Date: Mon, 6 Oct 2025 23:27:46 -0400
Subject: [PATCH] add: assigment 2

---
 assignment2/default.nix           | 26 +++++++++
 assignment2/part1/consumer.c      | 47 +++++++++++++++++
 assignment2/part1/producer.c      | 44 ++++++++++++++++
 assignment2/part1/test            | 47 +++++++++++++++++
 assignment2/part2/bidirectional.c | 56 ++++++++++++++++++++
 assignment2/part2/test            | 20 +++++++
 assignment2/part3/consumer.c      | 88 +++++++++++++++++++++++++++++++
 assignment2/part3/producer.c      | 63 ++++++++++++++++++++++
 assignment2/part3/test            | 33 ++++++++++++
 assignment2/test.nix              | 12 +++++
 flake.nix                         |  1 +
 11 files changed, 437 insertions(+)
 create mode 100644 assignment2/default.nix
 create mode 100644 assignment2/part1/consumer.c
 create mode 100644 assignment2/part1/producer.c
 create mode 100755 assignment2/part1/test
 create mode 100644 assignment2/part2/bidirectional.c
 create mode 100755 assignment2/part2/test
 create mode 100644 assignment2/part3/consumer.c
 create mode 100644 assignment2/part3/producer.c
 create mode 100755 assignment2/part3/test
 create mode 100644 assignment2/test.nix

diff --git a/assignment2/default.nix b/assignment2/default.nix
new file mode 100644
index 0000000..7f9f5b6
--- /dev/null
+++ b/assignment2/default.nix
@@ -0,0 +1,26 @@
+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";
+}
diff --git a/assignment2/part1/consumer.c b/assignment2/part1/consumer.c
new file mode 100644
index 0000000..8f0bc4b
--- /dev/null
+++ b/assignment2/part1/consumer.c
@@ -0,0 +1,47 @@
+#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;
+}
diff --git a/assignment2/part1/producer.c b/assignment2/part1/producer.c
new file mode 100644
index 0000000..291e39c
--- /dev/null
+++ b/assignment2/part1/producer.c
@@ -0,0 +1,44 @@
+#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;
+}
diff --git a/assignment2/part1/test b/assignment2/part1/test
new file mode 100755
index 0000000..4ed3156
--- /dev/null
+++ b/assignment2/part1/test
@@ -0,0 +1,47 @@
+#!/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" = "$(cat random.txt | head -n 5)"; then
+    echo "SUCCESS"
+fi
+rm random.txt
diff --git a/assignment2/part2/bidirectional.c b/assignment2/part2/bidirectional.c
new file mode 100644
index 0000000..c123f51
--- /dev/null
+++ b/assignment2/part2/bidirectional.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/wait.h>
+
+int main () {
+  int pipe1[2]; // Parent to child
+  int pipe2[2]; // Child to parent
+
+  // Create both pipes
+  if (pipe(pipe1) == -1 || pipe(pipe2) == -1) {
+    fprintf(stderr, "Could not open pipes");
+    return 1;
+  }
+
+  // Fork process
+  pid_t pid = fork();
+
+  if (pid == 0) {
+    // Child process
+
+    // Close unused pipe ends
+    close(pipe1[1]) ; // Close write end of pipe1
+    close(pipe2[0]) ; // Close read end of pipe2
+
+    // Read message, send response
+    char *message = malloc(100);
+    read(pipe1[0], message, 100);
+    printf("%s", message);
+    free(message);
+
+    char response[] = "Response from child to parent\n";
+    write(pipe2[1], response, sizeof(response));
+  } else {
+    // Parent process
+
+    // Close unused pipe ends
+    close(pipe1[0]) ; // Close read end of pipe1
+    close(pipe2[1]) ; // Close write end of pipe2
+
+    // Send message, read response
+    char message[] = "Sending message from parent to child\n";
+    write(pipe1[1], message, sizeof(message));
+
+    char *response = malloc(100);
+    read(pipe2[0], response, 100);
+    printf("%s", response);
+    free(response);
+
+    // Wait for child process to terminate
+    waitpid(pid, NULL, 0);
+  }
+
+  return 0;
+}
diff --git a/assignment2/part2/test b/assignment2/part2/test
new file mode 100755
index 0000000..f036c53
--- /dev/null
+++ b/assignment2/part2/test
@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+echo "Building executable..."
+
+cd "${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
diff --git a/assignment2/part3/consumer.c b/assignment2/part3/consumer.c
new file mode 100644
index 0000000..db66723
--- /dev/null
+++ b/assignment2/part3/consumer.c
@@ -0,0 +1,88 @@
+#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;
+}
diff --git a/assignment2/part3/producer.c b/assignment2/part3/producer.c
new file mode 100644
index 0000000..fb634fc
--- /dev/null
+++ b/assignment2/part3/producer.c
@@ -0,0 +1,63 @@
+#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;
+}
diff --git a/assignment2/part3/test b/assignment2/part3/test
new file mode 100755
index 0000000..d81d0a7
--- /dev/null
+++ b/assignment2/part3/test
@@ -0,0 +1,33 @@
+#!/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 "$(jobs -rp)"
+
+rm large.txt
diff --git a/assignment2/test.nix b/assignment2/test.nix
new file mode 100644
index 0000000..f04cf34
--- /dev/null
+++ b/assignment2/test.nix
@@ -0,0 +1,12 @@
+let
+  bash-test = subdir: { runCommandLocal }:
+    runCommandLocal "${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";
+}
diff --git a/flake.nix b/flake.nix
index 31faf94..03d2962 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,6 +10,7 @@
     let
       subdirs = [
         "assignment1"
+        "assignment2"
       ];
 
       eachSystem = nixpkgs.lib.genAttrs (import systems);