Day 3 Part 1 (Linux Kernel Module)

day3/aoc2023d3p1.c

@@ -0,0 +1,135 @@
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+
+#define MODULE_NAME "aoc2023d3p1"
+MODULE_AUTHOR("logan2611");
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_DESCRIPTION("Advent of Code 2023 Day 3 Part 1 (The Linux Kernel Module)");
+MODULE_VERSION("0.1");
+
+const int length = 140; // Number of lines
+//const int length = 10; // Number of lines
+const int width = length + 1; // Width of lines (including newline, carriage return or null terminator)
+
+// Parameter that specifies the input file
+static char *path = "/tmp/input";
+module_param(path, charp, S_IRUGO);
+MODULE_PARM_DESC(path, "The path to the data input.");
+
+static ssize_t read_input(struct file *file, loff_t pos, size_t n, char *buffer) {
+    ssize_t bytes_read;
+
+    bytes_read = kernel_read(file, buffer, n, &pos);
+    if (bytes_read < 0) {
+        pr_err("%s: Error reading file: %zd\n", MODULE_NAME, bytes_read);
+    }
+
+    return bytes_read;
+}
+
+static int find_numbers(char *top, char *middle, char *bottom) {
+    int beginning = -1;
+    int end = -1;
+    int sum = 0;
+
+    for(int i = 0; i < width; i++) {
+        if(i < end+1) continue;
+        if(middle[i] >= 48 && middle[i] <= 57) {
+            beginning = i-1;
+            end = i-1;
+            //pr_info("%s: %d\n", MODULE_NAME, i);
+
+            if(beginning < 0) {
+                beginning = 0;
+            }
+
+            for(int j = 0; j <= 4; j++) {
+                if(middle[i+j] < 48 || middle[i+j] > 57) {
+                    end = i+j;
+
+                    char numstr[8] = {0};
+                    memcpy(numstr, middle + i, j);
+
+                    int ret = 0;
+                    int err = 0;
+                    err = kstrtoint(numstr, 10, &ret);
+                    if (ret < 0) {
+                        pr_err("%s: Failed to convert string to number: \"%d\"\n", MODULE_NAME, err);
+                        return 0;
+                    }
+
+                    //pr_info("%s: %d %d %d\n", MODULE_NAME, ret, i, end);
+                    for(int k = 0; k <= end - beginning; k++) {
+                        //pr_info("%s: Checking position %d\n", MODULE_NAME, beginning+k);
+
+                        char topcheck = top[beginning+k];
+                        char middlecheck = middle[beginning+k];
+                        char bottomcheck = bottom[beginning+k];
+
+                        if( (((topcheck >= 33 && topcheck <= 47) || (topcheck >= 58 && topcheck <= 64)) && topcheck != '.') ||
+                            (((middlecheck >= 33 && middlecheck <= 47) || (middlecheck >= 58 && middlecheck <= 64)) && middlecheck != '.') ||
+                            (((bottomcheck >= 33 && bottomcheck <= 47) || (bottomcheck >= 58 && bottomcheck <= 64)) && bottomcheck != '.'))
+                        {
+                            pr_info("%s: ADJACENT %d\n", MODULE_NAME, ret);
+                            sum += ret;
+                            break;
+                        } else {
+                            //pr_info("%s: %d, %d and %d are not symbols\n", MODULE_NAME, topcheck, middlecheck, bottomcheck);
+                        };
+                    } // End Check for symbols loop
+                    break;
+                } // End Check for numbers loop
+            } // End find tail of number
+        } // End If number is found
+    } // End Find numbers loop
+    return sum;
+}
+
+
+
+static int __init test_init(void) {
+    struct file *f;
+
+    pr_info("%s: Module loaded\n", MODULE_NAME);
+
+    f = filp_open(path, O_RDONLY, 0);
+    if(IS_ERR(f)) {
+        pr_err("%s: Failed to open %s\n", MODULE_NAME, path);
+        return PTR_ERR(f);
+    }
+
+    char buf[3][width+1];
+    memset(buf, 0, sizeof(buf));
+
+    read_input(f, 0, width, buf[2]);
+
+    int sum = 0;
+
+    for(int line = 1; line <= length; line++) {
+        pr_info("%s: %s", MODULE_NAME, buf[2]);
+
+        memcpy(buf[0], buf[1], sizeof(buf[0]));
+        memcpy(buf[1], buf[2], sizeof(buf[1]));
+
+        if(length - line > 0) {
+            read_input(f, line*width, length, buf[2]);
+        } else {
+            memset(buf[2], 0, sizeof(buf[2]));
+        }
+
+        sum += find_numbers(buf[0], buf[1], buf[2]);
+    }
+
+    filp_close(f, NULL);
+
+    pr_info("%s: %d\n", MODULE_NAME, sum);
+    return 0;
+}
+
+static void __exit test_exit(void) {
+    pr_info("%s: Module unloaded\n", MODULE_NAME);
+}
+
+module_init(test_init);
+module_exit(test_exit);