On 11/28/25 16:26, Alyssa Ross wrote:
Demi Marie Obenour <demiobenour@gmail.com> writes:
On 11/28/25 16:14, Alyssa Ross wrote:
Demi Marie Obenour <demiobenour@gmail.com> writes:
On 11/28/25 08:22, Alyssa Ross wrote:
We want non-minimally-sized partitions to leave space for updates. All such partitions will also be labelled, so we can just add another optional field at the end.
Since we don't parse partition specifications in sh, we can't keep a running total any more, so instead we just go through the table at the end and add up all the sizes, taking advantage of our knowledge that the size will always be the last thing in each line in our tables.
Signed-off-by: Alyssa Ross <hi@alyssa.is> Message-ID: <20251127174054.2056835-2-hi@alyssa.is>
(snip)
# Keep 1MiB free at the start, and 1MiB free at the end. -gptBytes=$((ONE_MiB * 2)) -for partition; do - sizeMiB="$(sizeMiB "${partition%%:*}")" - table="$table${nl}size=${sizeMiB}MiB,$(awk -f "$scriptsDir/sfdisk-field.awk" -v partition="$partition")" - gptBytes="$((gptBytes + sizeMiB * ONE_MiB))" -done +gptMiB=2 +while read -r partition; do + # Here we rely on sfdisk-field.awk always putting size last. + : $((gptMiB += ${partition##*=})) +done <<EOF +$table +EOF
Nit: should ${partition##*=} be in double quotes?
I tried changing it, but it is apparently an "arithmetic syntax error" to use double quotes here.
I'd use a separate variable then.
Doesn't seem to make a difference. As an experiment:
partition="size=2 + 3" size=${partition##*=} printf "%s\n" $(($size))
This prints 5 even though a separate variable is used. It doesn't seem to be possible to get $(( … )) *not* to interpret arithmetic in variables.
In bash, but not busybox ash as used in Nix builds, it is possible to use double quotes like you suggested, but $(("$size")) is /still/ 5.
That's actually required by POSIX. What about: size=${partition##*=} : $((gptMiB += size)) ? -- Sincerely, Demi Marie Obenour (she/her/hers)