Updated driver and application

Module/tempMonitor.c

@@ -9,14 +9,18 @@
 #include <linux/stat.h>
 #include <linux/fs.h>
 #include <linux/err.h>
+#include <linux/random.h>
 
 #define DEVICE_NAME "temp_monitor"
 #define IOCTL_GET_TEMP _IOR('t', 1, int)
 #define TEMP_SENSOR_PATH "/sys/class/thermal/thermal_zone0/temp"
+#define BUF_LEN 100
 
 static int major_number;
 static struct class* temp_monitor_class = NULL;
 static struct device* temp_monitor_device = NULL;
+static char temp_unit[BUF_LEN] = "C"; // Default unit is Celsius
+static bool simulate_temp = false;
 
 static int device_open(struct inode *inode, struct file *file) {
     return 0;
@@ -26,33 +30,84 @@ static int device_release(struct inode *inode, struct file *file) {
     return 0;
 }
 
+static ssize_t device_read(struct file *file, char __user *buffer, size_t len, loff_t *offset) {
+    int temp = 0;
+    char temp_str[BUF_LEN];
+    struct file *f;
+    char *buf;
+    loff_t pos = 0;
+
+    if (simulate_temp) {
+        get_random_bytes(&temp, sizeof(temp));
+        temp = (temp % 40) + 10; // Simulate a temperature between 10 and 50 degrees
+    } else {
+        // Check if the temperature file exists
+        f = filp_open(TEMP_SENSOR_PATH, O_RDONLY, 0);
+        if (IS_ERR(f)) {
+            printk(KERN_INFO "temp_monitor: Temperature file not found\n");
+            return -EINVAL;
+        } else {
+            buf = kmalloc(16, GFP_KERNEL);
+            if (!buf) {
+                filp_close(f, NULL);
+                return -ENOMEM;
+            }
+
+            // Read the temperature
+            kernel_read(f, buf, 16, &pos);
+            sscanf(buf, "%d", &temp);
+            temp /= 1000; // Convert to degrees Celsius
+            filp_close(f, NULL);
+            kfree(buf);
+        }
+    }
+
+    // Convert to desired unit
+    if (strcmp(temp_unit, "F") == 0) {
+        temp = temp * 9 / 5 + 32; // Convert to Fahrenheit
+    } else if (strcmp(temp_unit, "K") == 0) {
+        temp += 273; // Convert to Kelvin
+    }
+
+    snprintf(temp_str, BUF_LEN, "%d %s\n", temp, temp_unit);
+
+    // Copy the result to user-space
+    if (copy_to_user(buffer, temp_str, strlen(temp_str) + 1)) {
+        return -EFAULT;
+    }
+
+    return strlen(temp_str) + 1;
+}
+
+static ssize_t device_write(struct file *file, const char __user *buffer, size_t len, loff_t *offset) {
+    char msg[BUF_LEN];
+
+    if (len > BUF_LEN - 1) {
+        return -EINVAL; // Input too long
+    }
+
+    if (copy_from_user(msg, buffer, len)) {
+        return -EFAULT;
+    }
+    msg[len] = '\0'; // Null-terminate the string
+
+    if (strcmp(msg, "simulate") == 0) {
+        simulate_temp = true;
+    } else {
+        simulate_temp = false;
+        strncpy(temp_unit, msg, BUF_LEN - 1);
+    }
+
+    printk(KERN_INFO "temp_monitor: Write operation: %s\n", msg);
+
+    return len;
+}
+
 static long device_ioctl(struct file *file, unsigned int cmd, unsigned long arg) {
     switch (cmd) {
         case IOCTL_GET_TEMP: {
             int temp = 0;
-            struct file *f;
-            char *buf;
-            loff_t pos = 0;
-
-            // Check if the temperature file exists
-            f = filp_open(TEMP_SENSOR_PATH, O_RDONLY, 0);
-            if (IS_ERR(f)) {
-                printk(KERN_INFO "temp_monitor: Temperature file not found\n");
-            } else {
-                buf = kmalloc(16, GFP_KERNEL);
-                if (!buf) {
-                    filp_close(f, NULL);
-                    return -ENOMEM;
-                }
-
-                // Read the temperature
-                kernel_read(f, buf, 16, &pos);
-                sscanf(buf, "%d", &temp);
-                temp /= 1000; // Convert to degrees Celsius
-                filp_close(f, NULL);
-                kfree(buf);
-            }
-
+            // Retrieve the temperature data here
             if (copy_to_user((int *)arg, &temp, sizeof(temp))) {
                 return -EACCES;
             }
@@ -67,6 +122,8 @@ static long device_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 static struct file_operations fops = {
     .open = device_open,
     .release = device_release,
+    .read = device_read,
+    .write = device_write,
     .unlocked_ioctl = device_ioctl,
 };
 

Test/Mohammed_UzairHamed_HW6_main.c

@@ -2,28 +2,54 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
+#include <string.h>
 
 #define IOCTL_GET_TEMP _IOR('t', 1, int)
 
+#define GREEN "\033[1;32m"
+#define RESET "\033[0m"
+
+void read_temp(int fd, const char *unit, int is_simulated) {
+    char buffer[128];
+    ssize_t bytes_read;
+
+    // Writing the desired unit or "simulate" command to the device
+    ssize_t bytes_written = write(fd, unit, strlen(unit));
+    if (bytes_written < 0) {
+        return; // Exit the function if writing fails
+    }
+
+    // Reading the temperature
+    bytes_read = read(fd, buffer, sizeof(buffer));
+    if (bytes_read < 0) {
+        return; // Exit the function if reading fails
+    } else {
+        buffer[bytes_read] = '\0'; // Null-terminate the string
+        if (is_simulated) {
+            printf(GREEN "CPU Temperature\n--- -----------\n" RESET "%s (simulated temperature)\n", buffer);
+        } else {
+            printf(GREEN "CPU Temperature\n--- -----------\n" RESET "%s\n", buffer);
+        }
+    }
+}
+
 int main() {
-    int fd, temp;
+    int fd;
+
     fd = open("/dev/temp_monitor", O_RDWR);
     if (fd < 0) {
         perror("Failed to open the device");
         return -1;
     }
 
-    if (ioctl(fd, IOCTL_GET_TEMP, &temp) == -1) {
-        perror("Failed to get temperature");
-        close(fd);
-        return -1;
-    }
+    // Requesting the temperature in Celsius
+    read_temp(fd, "C", 0);
 
-    if (temp == 0) {
-        printf("\033[32mCPU Temperature\n--- -----------\033[0m\n\033[31mCouldn't determine current temperature. Are you in a virtual machine?\033[0m\n");
-    } else {
-        printf("\033[32mCPU Temperature\n--- -----------\033[0m\n%d°C\n", temp);
-    }
+    // Requesting the temperature in Fahrenheit
+    read_temp(fd, "F", 0);
+
+    // Requesting simulated temperature
+    read_temp(fd, "simulate", 1);
 
     close(fd);
     return 0;