[PATCH] readelf: Report if no GOT section found

[Sam James]

Jan Beulich <jbeulich@suse.com> writes:

> On 02.09.2025 15:22, H.J. Lu wrote:
>> On Mon, Sep 1, 2025 at 11:01 PM Jan Beulich <jbeulich@suse.com> wrote:
>>>
>>> On 01.09.2025 20:00, H.J. Lu wrote:
>>>> @@ -21123,6 +21127,15 @@ process_got_section_contents (Filedata * filedata)
>>>>        }
>>>>
>>>>   out:
>>>> +  if (! found)
>>>> +    {
>>>> +      if (filedata->is_separate)
>>>> +     printf (_("\nThere is no GOT section in linked file '%s'.\n"),
>>>> +             filedata->file_name);
>>>> +      else
>>>> +     printf (_("\nThere is no GOT section in this file.\n"));
>>>> +    }
>>>
>>> I think that no such warning should appear when --got-contents wasn't used,
>>> but was implied from --all.
>>>
>> 
>> It just follows "readelf -a" for other options:
>> 
>> [hjl@gnu-cfl-3 tmp]$ rm x.c
>> [hjl@gnu-cfl-3 tmp]$ touch x.c
>> [hjl@gnu-cfl-3 tmp]$ gcc -c x.c
>> [hjl@gnu-cfl-3 tmp]$ readelf -a x.o
>> ELF Header:
>>   Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
>>   Class:                             ELF64
>>   Data:                              2's complement, little endian
>>   Version:                           1 (current)
>>   OS/ABI:                            UNIX - System V
>>   ABI Version:                       0
>>   Type:                              REL (Relocatable file)
>>   Machine:                           Advanced Micro Devices X86-64
>>   Version:                           0x1
>>   Entry point address:               0x0
>>   Start of program headers:          0 (bytes into file)
>>   Start of section headers:          304 (bytes into file)
>>   Flags:                             0x0
>>   Size of this header:               64 (bytes)
>>   Size of program headers:           0 (bytes)
>>   Number of program headers:         0
>>   Size of section headers:           64 (bytes)
>>   Number of section headers:         10
>>   Section header string table index: 9
>> 
>> Section Headers:
>>   [Nr] Name              Type             Address           Offset
>>        Size              EntSize          Flags  Link  Info  Align
>>   [ 0]                   NULL             0000000000000000  00000000
>>        0000000000000000  0000000000000000           0     0     0
>>   [ 1] .text             PROGBITS         0000000000000000  00000040
>>        0000000000000000  0000000000000000  AX       0     0     1
>>   [ 2] .data             PROGBITS         0000000000000000  00000040
>>        0000000000000000  0000000000000000  WA       0     0     1
>>   [ 3] .bss              NOBITS           0000000000000000  00000040
>>        0000000000000000  0000000000000000  WA       0     0     1
>>   [ 4] .comment          PROGBITS         0000000000000000  00000040
>>        000000000000002f  0000000000000001  MS       0     0     1
>>   [ 5] .note.GNU-stack   PROGBITS         0000000000000000  0000006f
>>        0000000000000000  0000000000000000           0     0     1
>>   [ 6] .note.gnu.pr[...] NOTE             0000000000000000  00000070
>>        0000000000000030  0000000000000000   A       0     0     8
>>   [ 7] .symtab           SYMTAB           0000000000000000  000000a0
>>        0000000000000030  0000000000000018           8     2     8
>>   [ 8] .strtab           STRTAB           0000000000000000  000000d0
>>        0000000000000005  0000000000000000           0     0     1
>>   [ 9] .shstrtab         STRTAB           0000000000000000  000000d5
>>        0000000000000058  0000000000000000           0     0     1
>> Key to Flags:
>>   W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
>>   L (link order), O (extra OS processing required), G (group), T (TLS),
>>   C (compressed), x (unknown), o (OS specific), E (exclude),
>>   D (mbind), l (large), p (processor specific)
>> 
>> There are no section groups in this file.
>> 
>> There are no program headers in this file.
>> 
>> There is no dynamic section in this file.
>> 
>> There are no relocations in this file.
>> No processor specific unwind information to decode
>> 
>> Symbol table '.symtab' contains 2 entries:
>>    Num:    Value          Size Type    Bind   Vis      Ndx Name
>>      0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
>>      1: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS x.c
>> 
>> No version information found in this file.
>
> Hmm, that's not very nice imo, but well - okay then.

I find it annoying but I assumed people were fine with it. We could add
a --verbose to get those 'notes' but I don't know if it's worth it
(testsuite churn).

>
> Jan

sam