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Fix raw efi build image size calculation (#4097)

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fixes #4095

Signed-off-by: Chris Irrgang <chris.irrgang@gmx.de>
This commit is contained in:
Chris Irrgang
2025-01-27 09:26:18 +01:00
committed by GitHub
parent 9398785bec
commit fd6839d0fe
2 changed files with 21 additions and 9 deletions
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28
tools/mkimage-raw-efi/make-efi
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@@ -55,30 +55,42 @@ menuentry 'LinuxKit ISO Image' {
}
EOF
#
# FAT filesystem config
FAT_SIZE=32
SECTOR_SIZE=512
SECTORS_PER_CLUSTER=8
# these always include the Boot Sector and FS Information Sector (sector 0 and 1) among others for FAT32
RESERVED_SECTORS=32
# calculate sizes
KERNEL_FILE_SIZE=$(stat -c %s "$KERNEL")
INITRD_FILE_SIZE=$(stat -c %s "$INITRD")
EFI_FILE_SIZE=$(stat -c %s "$BOOTFILE")
# minimum headroom needed in ESP, in bytes
# 511KiB headroom seems to be enough
ESP_HEADROOM=$(( 1024 * 1024 ))
GRUB_FILE_SIZE=$(stat -c %s EFI/BOOT/grub.cfg)
# this is the minimum size of our EFI System Partition
ESP_FILE_SIZE=$(( $KERNEL_FILE_SIZE + $INITRD_FILE_SIZE + $EFI_FILE_SIZE + $ESP_HEADROOM ))
ESP_DATA_SIZE=$(( $KERNEL_FILE_SIZE + $INITRD_FILE_SIZE + $EFI_FILE_SIZE + $GRUB_FILE_SIZE ))
ESP_DATA_SECTORS=$(( $ESP_DATA_SIZE / $SECTOR_SIZE ))
# File Allocation Table Sectors = (clusters + 2) * bytes per cluster / sector size
FILE_ALLOCATION_TABLE_SECTORS=$(( ( $ESP_DATA_SECTORS / $SECTORS_PER_CLUSTER + 2 ) * ( $FAT_SIZE / 8 ) / $SECTOR_SIZE ))
# there are two file allocation tables hence 2 * $FILE_ALLOCATION_TABLE_SECTORS
FAT_OVERHEAD_SECTORS=$(( $RESERVED_SECTORS + ( 2 * $FILE_ALLOCATION_TABLE_SECTORS ) ))
FAT_OVERHEAD_SIZE=$(( $FAT_OVERHEAD_SECTORS * $SECTOR_SIZE ))
# (x+1024)/1024*1024 rounds up to multiple of 1024KB, or 2048 sectors
# some firmwares get confused if the partitions are not aligned on 2048 blocks
# we will round up to the nearest multiple of 2048 blocks
# since each block is 512 bytes, we want the size to be a multiple of
# 2048 blocks * 512 bytes = 1048576 bytes = 1024KB
ESP_FILE_SIZE_KB=$(( ( ( ($ESP_FILE_SIZE+1024-1) / 1024 ) + 1024-1) / 1024 * 1024 ))
ESP_FILE_SIZE_KB=$(( ( ( ($ESP_DATA_SIZE + $FAT_OVERHEAD_SIZE + 1024 - 1) / 1024 ) + 1024 - 1) / 1024 * 1024 ))
# and for sectors
ESP_FILE_SIZE_SECTORS=$(( $ESP_FILE_SIZE_KB * 2 ))
ESP_FILE_SIZE_SECTORS=$(( $ESP_FILE_SIZE_KB * 1024 / $SECTOR_SIZE ))
# create a raw disk with an EFI boot partition
# Stuff it into a FAT filesystem, making it as small as possible.
mkfs.vfat -v -C $ESP_FILE $(( $ESP_FILE_SIZE_KB )) > /dev/null
mkfs.vfat -v -F $FAT_SIZE -S $SECTOR_SIZE -s $SECTORS_PER_CLUSTER -R $RESERVED_SECTORS -C $ESP_FILE $(( $ESP_FILE_SIZE_KB )) > /dev/null
echo "mtools_skip_check=1" >> /etc/mtools.conf && \
mmd -i $ESP_FILE ::/EFI
mmd -i $ESP_FILE ::/EFI/BOOT