core: file: Get boot volume

Signed-off-by: Ian M. <ian@aptel.org>

3 files changed, 85 insertions, 0 deletions

diff --git a/core/file.c b/core/file.c
new file mode 100644
index 0000000..717e506
--- /dev/null
+++ b/core/file.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2026, Apollo Telephone Laboratories.
+ * Provided under the BSD-3 clause.
+ */
+
+#include <sboot/file.h>
+#include <sboot/fwi.h>
+
+EFI_STATUS
+FileGetVolume(IN EFI_HANDLE ImageHandle, OUT EFI_FILE_HANDLE *Handle)
+{
+    EFI_LOADED_IMAGE *LoadedImage = NULL;
+    EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *IoVolume;
+    EFI_GUID LipGuid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+    EFI_GUID FsGuid = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+    EFI_FILE_HANDLE Volume;
+    EFI_STATUS Status;
+
+    Status = FwiHandleProtocol(
+        ImageHandle,
+        &LipGuid,
+        (VOID **)&LoadedImage
+    );
+
+    if (EFI_ERROR(Status)) {
+        Print(L"fatal: could not get loaded image\n");
+        return Status;
+    }
+
+    Status = FwiHandleProtocol(
+        LoadedImage->DeviceHandle,
+        &FsGuid,
+        (VOID *)&IoVolume
+    );
+
+    if (EFI_ERROR(Status)) {
+        Print(L"fatal: could not I/O volume\n");
+        return Status;
+    }
+
+    Status = uefi_call_wrapper(
+        IoVolume->OpenVolume,
+        2,
+        IoVolume,
+        &Volume
+    );
+
+    if (EFI_ERROR(Status)) {
+        Print(L"fatal: failed to get volume\n");
+        return Status;
+    }
+
+    *Handle = Volume;
+    return EFI_SUCCESS;
+}
diff --git a/core/sboot.c b/core/sboot.c
index 1a3d7d1..5511ca4 100644
--- a/core/sboot.c
+++ b/core/sboot.c
@@ -8,12 +8,16 @@
 #include <sboot/sboot.h>
 #include <sboot/config.h>
 #include <sboot/fwi.h>
+#include <sboot/file.h>
+
+EFI_FILE_HANDLE gBootVolume;
 
 EFI_STATUS
 EFIAPI
 efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
 {
     BOOT_ENTRY Entry;
+    EFI_STATUS Status;
 
     InitializeLib(ImageHandle, SystemTable);
 
@@ -25,6 +29,11 @@ efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
         NULL
     );
 
+    Status = FileGetVolume(ImageHandle, &gBootVolume);
+    if (EFI_ERROR(Status)) {
+        Hcf();
+    }
+
     Print(
         L"SBOOT %s - %d boot entrie(s)\n",
         SBOOT_VERSION,
diff --git a/head/sboot/file.h b/head/sboot/file.h
new file mode 100644
index 0000000..cdae2bc
--- /dev/null
+++ b/head/sboot/file.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2026, Apollo Telephone Laboratories.
+ * Provided under the BSD-3 clause.
+ */
+
+#ifndef _SBOOT_FILE_H_
+#define _SBOOT_FILE_H_ 1
+
+#include <efi.h>
+#include <efilib.h>
+
+extern EFI_FILE_HANDLE gBootVolume;
+
+/*
+ * Obtain the boot volume
+ *
+ * @ImageHandle:  Image handle
+ */
+EFI_STATUS FileGetVolume(IN EFI_HANDLE ImageHandle, OUT EFI_FILE_HANDLE *Handle);
+
+#endif  /* !_SBOOT_FILE_H_ */