core: file: Get boot volume

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

1 files changed, 55 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;
+}