Re: [PATCH v1 4/7] ld.texi: Add ASCII to info file

[Jan Beulich <jbeulich@suse.com>]

On 08.07.2024 12:57, Ulf Samuelsson wrote:
> 
> Den 2024-07-08 kl. 08:18, skrev Jan Beulich:
>> On 05.07.2024 17:38, Ulf Samuelsson wrote:
>>> Den 2024-07-02 kl. 10:12, skrev Jan Beulich:
>>>> First: Please don't drop the mailing list from Cc. Second: Please don't
>>>> top-post.
>>>>
>>>> On 02.07.2024 00:21, Ulf Samuelsson wrote:
>>>>> I submitted the code in this patch series more than a year ago, and it got accepted.
>>>>> Then a lot was reverted since I had not assigned the copyright to FSF.
>>>>> For unknown reasons, my ASCIZ patches remained, but the ASCII stuff was reverted.
>>>>> The reason for the naming is to be similar to how I remember naming in some assemblers where ASCIZ is zero terminated and ASCII is not zero terminated.
>>>>>
>>>>> If the string is too long, so it does not fit, it is really an error.
>>>>> Adding a zero when truncating is a little less intrusive and may reduce runtime errors.
>>>>> ASCII tells people what it is meant to be doing. ASCIIZ will make a lot of people wonder what the difference is between ASCIZ and ASCIIZ. It will also be misleading, because it does not add a zero if the string fits.
>>>> Then did I read the code wrong? I was left with the impression that you'll
>>>> truncate at size-1, to ensure zero termination. Plus as you say in this
>>>> doc, size being 0 results in ASCIZ behavior, i.e. zero-terminates too.
>>>                "          111111"
>>>                "0123456789012345"
>>>
>>>     ASCII (16) "This is a string"
>>>
>>>     results in 'size' == 16. Since the string is 16 characters, 'len'
>>> will be 16 as well.
>> And hence
>>
>>    else if (len >= size)
>>      {
>>        len = size - 1;
>>
>> would reduce len down to 15 afaics, such that ...
>>
> Given *ASCII 16, "This is 16 bytes*"  size == 16 and strlen("This is 16 
> bytes") == 16,
> the linker should add a 16 byte area without a terminating NUL,
> 
> If the string is shorter, then the linker should pad with NUL.
> 
> If the string is longer, then the linker should truncate the string 
> adding a NUL
> at the end, still fitting in the area. A warning should be issued.

What I'm still actually missing a reason for is why in this case you
want to insert a nul while in the len == size case you want to keep
the string as is. To me this is inconsistent and hence yielding
surprising behavior. Yet with that harmonized (whichever direction)
it'll then become clear whether the directive wants to be ASCII or
ASCIZ (or alike).

Jan