Add builder.rs

src/fat.rs

@@ -15,20 +15,34 @@ pub fn create_fat_image(
     kernel_path: &Path,
 ) -> io::Result<u32> {
     println!("create_fat_image: Starting creation of FAT image.");
+    println!("create_fat_image: fat_img_path: {:?}", fat_img_path);
+    println!("create_fat_image: loader_path: {:?}", loader_path);
+    println!("create_fat_image: kernel_path: {:?}", kernel_path);
 
     // Ensure both files exist
     if !loader_path.exists() {
+        println!(
+            "create_fat_image: Loader file NOT found at {:?}",
+            loader_path
+        );
         return Err(io::Error::new(
             io::ErrorKind::NotFound,
             format!("Loader file not found at {:?}", loader_path),
         ));
     }
+    println!("create_fat_image: Loader file found at {:?}", loader_path);
+
     if !kernel_path.exists() {
+        println!(
+            "create_fat_image: Kernel file NOT found at {:?}",
+            kernel_path
+        );
         return Err(io::Error::new(
             io::ErrorKind::NotFound,
             format!("Kernel file not found at {:?}", kernel_path),
         ));
     }
+    println!("create_fat_image: Kernel file found at {:?}", kernel_path);
 
     // Calculate the minimum image size based on both files
     let loader_size = loader_path.metadata()?.len();

src/iso/boot_catalog.rs

@@ -14,20 +14,24 @@ pub const BOOT_CATALOG_EFI_PLATFORM_ID: u8 = 0xEF;
 pub const ID_FIELD_OFFSET: usize = 4;
 pub const BOOT_CATALOG_CHECKSUM_OFFSET: usize = 28;
 
-/// Writes an El Torito boot catalog for UEFI.
-pub fn write_boot_catalog(
-    iso: &mut File,
-    boot_img_lba: u32,
-    boot_img_sectors: u16,
-) -> io::Result<()> {
+pub struct BootCatalogEntry {
+    pub platform_id: u8,
+    pub boot_image_lba: u32,
+    pub boot_image_sectors: u16,
+    pub bootable: bool,
+}
+
+/// Writes an El Torito boot catalog.
+pub fn write_boot_catalog(iso: &mut File, entries: Vec<BootCatalogEntry>) -> io::Result<()> {
     pad_to_lba(iso, LBA_BOOT_CATALOG)?;
 
     let mut catalog = [0u8; ISO_SECTOR_SIZE];
+    let mut offset = 0;
 
     // Validation Entry (32 bytes)
     let mut val = [0u8; 32];
     val[0] = BOOT_CATALOG_VALIDATION_ENTRY_HEADER_ID;
-    val[1] = BOOT_CATALOG_EFI_PLATFORM_ID;
+    val[1] = BOOT_CATALOG_EFI_PLATFORM_ID; // This is for the primary boot entry, usually UEFI
 
     // ID string "UEFI" + zero padding (24 bytes total)
     val[ID_FIELD_OFFSET..ID_FIELD_OFFSET + 24]
@@ -46,18 +50,26 @@ pub fn write_boot_catalog(
     let checksum = 0u16.wrapping_sub(sum);
     val[BOOT_CATALOG_CHECKSUM_OFFSET..BOOT_CATALOG_CHECKSUM_OFFSET + 2]
         .copy_from_slice(&checksum.to_le_bytes());
-    catalog[0..32].copy_from_slice(&val);
-
-    // Default Boot Entry (32 bytes)
-    let mut entry = [0u8; 32];
-    entry[0] = BOOT_CATALOG_BOOT_ENTRY_HEADER_ID; // Bootable
-    entry[1] = 0x00; // No Emulation
-    entry[2..4].copy_from_slice(&0u16.to_le_bytes()); // Load Segment
-    entry[4] = BOOT_CATALOG_EFI_PLATFORM_ID; // System Type
-    entry[5] = 0x00; // Unused
-    entry[6..8].copy_from_slice(&boot_img_sectors.to_le_bytes()); // Sector count (u16, in 512-byte sectors)
-    entry[8..12].copy_from_slice(&boot_img_lba.to_le_bytes());
-    catalog[32..64].copy_from_slice(&entry);
+    catalog[offset..offset + 32].copy_from_slice(&val);
+    offset += 32;
+
+    // Boot Entries
+    for entry_data in entries {
+        let mut entry = [0u8; 32];
+        entry[0] = if entry_data.bootable {
+            BOOT_CATALOG_BOOT_ENTRY_HEADER_ID
+        } else {
+            0x00
+        }; // Bootable or not
+        entry[1] = 0x00; // No Emulation
+        entry[2..4].copy_from_slice(&0u16.to_le_bytes()); // Load Segment
+        entry[4] = entry_data.platform_id; // System Type
+        entry[5] = 0x00; // Unused
+        entry[6..8].copy_from_slice(&entry_data.boot_image_sectors.to_le_bytes()); // Sector count (u16, in 512-byte sectors)
+        entry[8..12].copy_from_slice(&entry_data.boot_image_lba.to_le_bytes());
+        catalog[offset..offset + 32].copy_from_slice(&entry);
+        offset += 32;
+    }
 
     iso.write_all(&catalog)
 }