Always create object path that depend upon external ids validating the strings. Fixes #86.

Signed-off-by: Federico Di Pierro <nierro92@gmail.com>

Author: FedeDP

src/modules/backlight2.c

@@ -1,5 +1,6 @@
 #include <polkit.h>
 #include <udev.h>
+#include <bus_utils.h>
 #include <math.h>
 #include <module/map.h>
 #include <linux/fb.h>
@@ -153,7 +154,7 @@ MODULE("BACKLIGHT2");
                             d->sn = strdup(id);
                             d->max = VALREC_MAX_VAL(valrec);
                             d->cookie = curr_cookie;
-                            snprintf(d->obj_path, sizeof(d->obj_path) - 1, "%s/%s", object_path, d->sn);
+                            make_valid_obj_path(d->obj_path, sizeof(d->obj_path), object_path, d->sn);
                             int r = sd_bus_add_object_vtable(bus, &d->slot, d->obj_path, bus_interface, vtable, d);
                             if (r < 0) {
                                 m_log("Failed to add object vtable on path '%s': %d\n", d->obj_path, r);
@@ -365,7 +366,7 @@ static int store_internal_device(struct udev_device *dev, void *userdata) {
         d->sn = strdup(id);
         // Unused. But receive() callback expects brightness value to be cached
         udev_device_get_sysattr_value(dev, "brightness");
-        snprintf(d->obj_path, sizeof(d->obj_path) - 1, "%s/%s", object_path, d->sn);
+        make_valid_obj_path(d->obj_path, sizeof(d->obj_path), object_path, d->sn);
         ret = sd_bus_add_object_vtable(bus, &d->slot, d->obj_path, bus_interface, vtable, d);
         if (ret < 0) {
             m_log("Failed to add object vtable on path '%s': %d\n", d->obj_path, ret);

src/modules/keyboard.c

@@ -1,6 +1,7 @@
 #include <polkit.h>
 #include <udev.h>
 #include <math.h>
+#include <bus_utils.h>
 #include <module/map.h>
 
 #define KBD_SUBSYSTEM           "leds"
@@ -155,15 +156,7 @@ static int kbd_new(struct udev_device *dev, void *userdata) {
     k->max = atoi(udev_device_get_sysattr_value(dev, "max_brightness"));
     k->sysname = strdup(udev_device_get_sysname(dev));
 
-    /*
-     * Substitute wrong chars, eg: dell::kbd_backlight -> dell__kbd_backlight
-     * See spec: https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-marshaling-object-path
-     */
-    snprintf(k->obj_path, sizeof(k->obj_path) - 1, "%s/%s", object_path, k->sysname);
-    char *ptr = NULL;
-    while ((ptr = strchr(k->obj_path, ':'))) {
-        *ptr = '_';
-    }
+    make_valid_obj_path(k->obj_path, sizeof(k->obj_path), object_path, k->sysname);
 
     int r = sd_bus_add_object_vtable(bus, &k->slot, k->obj_path, bus_interface, vtable, k);
     if (r < 0) {

src/utils/bus_utils.c

@@ -43,3 +43,24 @@ const char *bus_sender_xauth(void) {
     }
     return NULL;
 }
+
+void make_valid_obj_path(char *storage, size_t size, const char *root, const char *basename) {
+    /*
+     * Substitute wrong chars, eg: dell::kbd_backlight -> dell__kbd_backlight
+     * See spec: https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-marshaling-object-path
+     */
+    const char *valid_chars = "ABCDEFGHIJKLMNOPQRSTUWXYZabcdefghijklmnopqrstuvwxyz0123456789_";
+    
+    snprintf(storage, size, "%s/%s", root, basename);
+    
+    char *path = storage + strlen(root) + 1;
+    const int full_len = strlen(path);
+    
+    while (true) {
+        int len = strspn(path, valid_chars);
+        if (len == full_len) {
+            break;
+        }
+        path[len] = '_';
+    }
+}

src/utils/bus_utils.h

@@ -3,3 +3,5 @@
 int bus_sender_fill_creds(sd_bus_message *m);
 const char *bus_sender_runtime_dir(void);
 const char *bus_sender_xauth(void);
+
+void make_valid_obj_path(char *storage, size_t size, const char *root, const char *basename);