diff --git a/src/fs/iso/mod.rs b/src/fs/iso/mod.rs
index 94ce10c..a1b47d1 100644
--- a/src/fs/iso/mod.rs
+++ b/src/fs/iso/mod.rs
@@ -6,7 +6,7 @@ use crate::drivers::atapi::{DRIVE};
 use crate::fd::{FD_TABLE, FDt};
 use crate::utils::unserialize;
 
-use iso9660::{IsoPrimVolDesc};
+use iso9660::{IsoPrimVolDesc, IsoDir};
 use fd::IsoFD;
 
 pub async fn get_prim_vol_desc() -> IsoPrimVolDesc {
@@ -20,8 +20,18 @@ pub async fn get_prim_vol_desc() -> IsoPrimVolDesc {
     *unserialize::<IsoPrimVolDesc>(desc_block.as_ptr())
 }
 
-pub async fn open() -> FDt {
+pub async fn open(path: &str, flags: u32) -> Option<FDt> {
+    if flags != crate::syscalls::io::O_RDONLY {
+        return None;
+    }
+
+    let voldesc = get_prim_vol_desc().await;
+
+    if voldesc.std_identifier != "CD001".as_bytes() {
+        return None;
+    }
+
     let fd = IsoFD::new();
     FD_TABLE.lock().await.register_fd(fd.clone());
-    fd
+    Some(fd)
 }
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index a2b8aad..55bb752 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,7 @@ mod task;
 mod fs;
 mod utils;
 mod fd;
+mod syscalls;
 
 //#[macro_use]
 extern crate alloc;
@@ -64,6 +65,6 @@ pub extern "C" fn julios_main(multiboot_info_addr: usize) -> ! {
 
 
 async fn get_file() {
-    let fd = fs::iso::open().await;
+    let fd = fs::iso::open("test", syscalls::io::O_RDONLY).await.unwrap();
     fd.borrow_mut().read(&[], 0).await;
 }
\ No newline at end of file
diff --git a/src/syscalls/io.rs b/src/syscalls/io.rs
new file mode 100644
index 0000000..be60c0f
--- /dev/null
+++ b/src/syscalls/io.rs
@@ -0,0 +1,7 @@
+// open flags
+pub const O_RDONLY: u32 = 0;
+
+// seek flags
+pub const SEEK_SET: u32 = 0;
+pub const SEEK_CUR: u32 = 1;
+pub const SEEK_END: u32 = 2;
\ No newline at end of file
diff --git a/src/syscalls/mod.rs b/src/syscalls/mod.rs
new file mode 100644
index 0000000..678b90e
--- /dev/null
+++ b/src/syscalls/mod.rs
@@ -0,0 +1 @@
+pub mod io;
\ No newline at end of file