Re: [pve-devel] [PATCH pve-kernel-meta] proxmox-boot: trim /etc/kernel/cmdline before appending

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 10.11.21 15:28, Dominik Csapak wrote:
> comment inline
> 
> On 11/10/21 15:15, Stoiko Ivanov wrote:
>> following the commit of removing the wrong indentation of the linux
>> and initrd lines - this commit strips empty lines (and leading
>> trailing whitespace) in /etc/kernel/cmdline.
>>
>> I managed to reproduce the issue reported in the forum [0] by adding
>> empty lines to /etc/kernel/cmdline) - without this - systemd-boot
>> booted quite happily even with the indentation.
>>
>> quickly tested on a VM.
>>
>> [0]: https://forum.proxmox.com/threads/problem-with-proxmox-boot-tool.99043/
>>
>> Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
>> ---
>>   proxmox-boot/zz-proxmox-boot | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/proxmox-boot/zz-proxmox-boot b/proxmox-boot/zz-proxmox-boot
>> index 52171b2..2356c74 100755
>> --- a/proxmox-boot/zz-proxmox-boot
>> +++ b/proxmox-boot/zz-proxmox-boot
>> @@ -50,7 +50,7 @@ update_esps() {
>>           exit 0
>>       fi
>>       if [ -f /etc/kernel/cmdline ]; then
>> -        CMDLINE="$(cat /etc/kernel/cmdline)"
>> +        CMDLINE="$(sed -re '/^\s*$/d;s/^\s+(\S*)\s+$/\1/g' /etc/kernel/cmdline)"
> 
> while the first  part of the regex looks good (delete all lines that only contain whitespace (or nothing), the second part will often not trigger since there is not *only* non-whitespace in the middle?
> 
> should it not be more like:
> 
> '^\s+(.*?)\s+$/\1/g' ?

or just care for trailing whitespaces, i.e. use `head -n 1 /etc/kernel/cmdline` ?

Or alternatively using read should work too:
read -r CMDLINE < /etc/kernel/cmdline 

Important in general is that we only get a single line to not break tools that expect
that during the boot process.