Add boundary checking to prevent incorrect prefix matches

Co-authored-by: JohnAmadis <17320783+JohnAmadis@users.noreply.github.com>

Author: Copilot

src/dmvfs.c

@@ -344,7 +344,16 @@ static mount_point_t* get_mount_point_for_path(const char* path)
         if(g_mount_points[i].mount_point != NULL)
         {
             size_t mount_point_length = strlen(g_mount_points[i].mount_point);
+            // Check if path starts with mount point and either:
+            // - The mount point is the root "/" (special case - matches all paths)
+            // - The mount point is exactly the path (path[mount_point_length] == '\0')
+            // - The next character is a path separator (path[mount_point_length] == '/')
+            // This ensures we match at path boundaries only
+            bool is_root_mount = (mount_point_length == 1 && g_mount_points[i].mount_point[0] == '/');
+            bool is_boundary_match = (path[mount_point_length] == '/' || path[mount_point_length] == '\0');
+            
             if(strncmp(path, g_mount_points[i].mount_point, mount_point_length) == 0 &&
+               (is_root_mount || is_boundary_match) &&
                mount_point_length > best_match_length)
             {
                 best_match = &g_mount_points[i];

tests/test_mount_point_selection.c

@@ -28,7 +28,7 @@ int main(int argc, char *argv[])
     if (argc < 3) {
         printf("Usage: %s <fs1_module.dmf> <fs2_module.dmf>\n", argv[0]);
         printf("This test requires two filesystem modules to test mount point selection.\n");
-        return 1;
+        return -1;
     }
 
     const char* fs1_path = argv[1];