314-follow-symlinks-when-measuring-size-of-efi-files.patch

From bcc8b04f78cf99ffa9662b68675f346904c7aecd Mon Sep 17 00:00:00 2001
From: David Hewitt <davidmhewitt@gmail.com>
Date: Wed, 12 Jul 2023 20:29:04 +0000
Subject: [PATCH] Follow symlinks while copying shim files

The shim EFI file on Ubuntu can be a symlink, as it may be in the alternatives system, so
previously, when calculating the size of the FAT32 partition, we would measure the size of the
symlink instead of the actual file and get "Disk full" errors when trying to copy the files into
the new FAT32 partition.

If we dereference the file on copy, we get the actual file and can calculate the size accurately.

```
lrwxrwxrwx. 1 root root   36 Jul 12 20:04 bootx64.efi -> /etc/alternatives/shimx64.efi.signed
```
---
 binary_grub-efi | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/binary_grub-efi b/binary_grub-efi
index d504569cb..ccac228b8 100755
--- a/binary_grub-efi
+++ b/binary_grub-efi
@@ -185,12 +185,14 @@ gen_efi_boot_img(){
 	#   USB flash drive, while grubx64.efi.signed is for hard drive.
 	#   Therefore here gcdx64.efi.signed is used for amd64 and gcdaa64.efi.signed is
 	#   for arm64.
+	# - Ubuntu's shim binary is in the alternatives system so it could be a symlink,
+	#   so ensure we dereference it and copy the actual file
 	if [ -r ${_CHROOT_DIR}/usr/lib/grub/\$platform-signed/gcd\$efi_name.efi.signed -a \
 			-r ${_CHROOT_DIR}/usr/lib/shim/shim\$efi_name.efi.signed -a \
 			"${LB_UEFI_SECURE_BOOT}" != "disable" ]; then
 		cp -a ${_CHROOT_DIR}/usr/lib/grub/\$platform-signed/gcd\$efi_name.efi.signed \
 			${_CHROOT_DIR}/grub-efi-temp/EFI/boot/grub\$efi_name.efi
-		cp -a ${_CHROOT_DIR}/usr/lib/shim/shim\$efi_name.efi.signed \
+		cp -a --dereference ${_CHROOT_DIR}/usr/lib/shim/shim\$efi_name.efi.signed \
 			${_CHROOT_DIR}/grub-efi-temp/EFI/boot/boot\$efi_name.efi
 	fi
 }
--
GitLab