[PATCH v2 1/1] readelf: invalid error message triggered when last tag is an empty string

[Richard Earnshaw (lists)]

On 23/06/2025 10:48, Jan Beulich wrote:
> On 23.06.2025 11:23, Matthieu Longo wrote:
>> On 2025-06-23 06:53, Jan Beulich wrote:
>>> On 20.06.2025 17:13, Matthieu Longo wrote:
>>>> On 2025-06-20 09:40, Jan Beulich wrote:
>>>>> On 19.06.2025 10:43, Matthieu Longo wrote:
>>>>>> +	    print_symbol_name ((int) maxlen, (const char *) p);
>>>>>
>>>>> ... the function will bail early if passed 0.
>>>>>
>>>>> However - is using print_symbol_name() actually correct here? Surely it
>>>>> is bogus to demangle this string, in the (however unlikely) event that it
>>>>> turns out demanglable?
>>>>
>>>> I think that it is correct. It will print "[...]" for a string finishing
>>>> with no null terminator, but you can trigger the printing of the string
>>>> until a maximum of maxlen if you pass -T (--silent-truncation) to readelf.
>>>
>>> You don't touch on the demangling aspect at all?
>>
>> Demangling should not be needed for object attributes, but 
>> print_symbol_name() has been working up until now, I don't have plan to 
>> change it unless there is a good reason.
>>
>> Do you mean by bogus here that a demangling could mistakenly be applied 
>> on a non-mangled string starting with chance with _Z for instance ?
> 
> Yes, that's what I mean. Imo the function should be used only for what
> truly is a symbol name. (It's likely even wrong to call it for e.g.
> section names, for the same reason.)
> 
> Jan

Well looking through readelf there are /many/ places where print_symbol_name is called with something that is obviously not a symbol:

        print_symbol_name (22, sec_name);

        print_symbol_name (-17, printable_section_name (filedata, section));

Are a couple of obvious ones.

ISTM that it's probably the name of this function that is now misleading rather than this use that is especially incorrect and really the name should reflect that it is a general output routine with some formatting assistance (padding or length limiting).

R.