refactor(MP/daemon): use mutex and atomic operations in application and ipc

src/06-mini-project/daemon/application/app.c

@@ -3,7 +3,9 @@
 
 #include <pthread.h>
 #include <unistd.h>
-#include <stdio.h>
+#include <stdbool.h>
+
+#include <stdatomic.h>
 
 static LED* led;
 
@@ -11,10 +13,11 @@ static LED* led;
 static pthread_t anim_thread_id;
 static pthread_mutex_t anim_lock = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t anim_condition = PTHREAD_COND_INITIALIZER; // SHARED RESOURCES
+static pthread_mutex_t app_lock = PTHREAD_MUTEX_INITIALIZER;
 
 /* The counter of pending animations */
 static int pending_animations = 0; // SHARED RESOURCES
-static int keep_running = 1;
+static atomic_bool keep_running = true;
 
 void btn_set_led(LED* l) {
     if (l != NULL) {
@@ -31,13 +34,19 @@ uint32_t get_period() {
 }
 
 void increase_period() {
+    pthread_mutex_lock(&app_lock);
     uint32_t current_period = sysfs_get_period();
     set_period(current_period + GAP_PERIOD_MS);
+    pthread_mutex_unlock(&app_lock);
 }
 
 void decrease_period() {
+    pthread_mutex_lock(&app_lock);
     uint32_t current_period = sysfs_get_period();
-    set_period(current_period - GAP_PERIOD_MS);
+    if (current_period > GAP_PERIOD_MS) {
+        set_period(current_period - GAP_PERIOD_MS);
+    }
+    pthread_mutex_unlock(&app_lock);
 }
 
 int get_mode() {
@@ -49,8 +58,10 @@ void set_mode(int mode) {
 }
 
 void mode_toggle() {
+    pthread_mutex_lock(&app_lock);
     int current_mode = sysfs_get_mode();
     set_mode(current_mode ^ 1);
+    pthread_mutex_unlock(&app_lock);
 }
 
 float get_temperature() {
@@ -93,9 +104,9 @@ static void* animation_worker(void* arg) {
         /* Perform the visual task */
         if (led != NULL) {
             LED_on(led);
-            usleep(150000);
+            usleep(20000);
             LED_off(led);
-            usleep(100000); /* Small delay between consecutive pulses */
+            usleep(50000); /* Small delay between consecutive pulses */
         }
     }
     return NULL;

src/06-mini-project/daemon/application/sysfs.c

@@ -1,13 +1,16 @@
 #include "sysfs.h"
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>
 
+#include <pthread.h>
 
+static pthread_mutex_t sysfs_lock = PTHREAD_MUTEX_INITIALIZER;
 
 float sysfs_get_temperature() {
+    pthread_mutex_lock(&sysfs_lock);
     FILE *f = fopen(PATH_TEMPERATURE, "r");
     if (f == NULL) {
+        pthread_mutex_unlock(&sysfs_lock);
         return 0.0f; /* Return 0.0 if the kernel module is not loaded */
     }
 
@@ -19,48 +22,70 @@ float sysfs_get_temperature() {
     */
     if (fscanf(f, "%f", &temp) == 1) {
         fclose(f);
+        pthread_mutex_unlock(&sysfs_lock);
         return temp;
     }
 
     fclose(f);
+    pthread_mutex_unlock(&sysfs_lock);
     return 0.0f;
 }
 
 uint32_t sysfs_get_mode() {
+    pthread_mutex_lock(&sysfs_lock);
     FILE *f = fopen(PATH_MODE, "r");
-    if (f == NULL) return 0;
+    if (f == NULL) {
+        pthread_mutex_unlock(&sysfs_lock);
+        return 0;
+    }
 
     uint32_t mode = 0;
     fscanf(f, "%u", &mode);
     fclose(f);
+    pthread_mutex_unlock(&sysfs_lock);
 
     return mode;
 }
 
 void sysfs_set_mode(uint32_t mode) {
+    pthread_mutex_lock(&sysfs_lock);
     FILE *f = fopen(PATH_MODE, "w");
-    if (f == NULL) return;
+    if (f == NULL) {
+        pthread_mutex_unlock(&sysfs_lock);
+        return;
+    }
 
     /* Write the integer as an ASCII string */
     fprintf(f, "%u\n", mode);
     fclose(f);
+    pthread_mutex_unlock(&sysfs_lock);
 }
 
 uint32_t sysfs_get_period() {
+    pthread_mutex_lock(&sysfs_lock);
     FILE *f = fopen(PATH_PERIOD_ST, "r");
-    if (f == NULL) return 0;
+    if (f == NULL) {
+        pthread_mutex_unlock(&sysfs_lock);
+        return 0;
+    }
 
     uint32_t period = 0;
     fscanf(f, "%u", &period);
     fclose(f);
+    pthread_mutex_unlock(&sysfs_lock);
 
     return period;
 }
 
 void sysfs_set_period(uint32_t period) {
+    pthread_mutex_lock(&sysfs_lock);
     FILE *f = fopen(PATH_PERIOD_SET, "w");
-    if (f == NULL) return;
+    if (f == NULL) {
+        pthread_mutex_unlock(&sysfs_lock);
+        return;
+    }
 
     fprintf(f, "%u\n", period);
     fclose(f);
+    pthread_mutex_unlock(&sysfs_lock);
 }

src/06-mini-project/daemon/ipc/ipc_server.c

@@ -7,17 +7,22 @@
 #include <pthread.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <stdbool.h>
+
+#include <stdatomic.h>
 
 /* Global variables for the IPC module */
 static int server_fd = -1;
 static pthread_t ipc_thread;
 static struct ipc_callbacks_t current_cbs = {0};
-static int is_running = 0;
+static pthread_mutex_t cb_mutex = PTHREAD_MUTEX_INITIALIZER;
+static atomic_bool is_running = false;
 
 /**
  * process_message() - Route the received IPC message to the correct callback.
  */
 static void process_message(ipc_msg_t *msg) {
+    pthread_mutex_lock(&cb_mutex);
     switch (msg->command) {
         case CMD_SET_MODE:
             if (current_cbs.on_set_mode) {
@@ -47,6 +52,7 @@ static void process_message(ipc_msg_t *msg) {
             printf("[IPC] Received unknown command: %d\n", msg->command);
             break;
     }
+    pthread_mutex_unlock(&cb_mutex);
 }
 
 /**
@@ -92,9 +98,11 @@ int start_ipc_server(struct ipc_callbacks_t *cbs) {
     }
 
     /* Save the provided callbacks */
+    pthread_mutex_lock(&cb_mutex);
     if (cbs) {
         current_cbs = *cbs;
     }
+    pthread_mutex_unlock(&cb_mutex);
 
     /* Create local socket */
     server_fd = socket(AF_UNIX, SOCK_DGRAM, 0);
@@ -139,7 +147,7 @@ int stop_ipc_server(void) {
     printf("[IPC] Stopping server...\n");
 
     /* Signal thread to stop */
-    is_running = 0;
+    atomic_store(&is_running, false);
 
     /* Unblock the recvfrom() by shutting down the socket */
     if (server_fd != -1) {
@@ -155,7 +163,9 @@ int stop_ipc_server(void) {
     unlink(SOCKET_PATH);
 
     /* Clear callbacks */
+    pthread_mutex_lock(&cb_mutex);
     memset(&current_cbs, 0, sizeof(struct ipc_callbacks_t));
+    pthread_mutex_unlock(&cb_mutex);
 
     return 0;
 }