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

[Jan Beulich]

On 23.06.2025 12:50, Richard Earnshaw (lists) wrote:
> 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.)
> 
> 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).

Except that then the function would need to have a boolean added indicating whether
to try demangling in the first place.

Jan