[Bug,tools/29719] New: eu-readelf -s=section is confusing

Message ID bug-29719-10460@http.sourceware.org/bugzilla/
State Superseded
Headers
Series [Bug,tools/29719] New: eu-readelf -s=section is confusing |

Commit Message

mliska at suse dot cz Oct. 24, 2022, 12:13 p.m. UTC
  https://sourceware.org/bugzilla/show_bug.cgi?id=29719

            Bug ID: 29719
           Summary: eu-readelf -s=section is confusing
           Product: elfutils
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tools
          Assignee: unassigned at sourceware dot org
          Reporter: mliska at suse dot cz
                CC: elfutils-devel at sourceware dot org, mjw at fedoraproject dot org
  Target Milestone: ---

Note there's a difference in between binutils and elfutils where the later on
has an optional argument:

       --symbols [section name]

I have a few comments:

1) it's confusing as one expects that all symbols in "section name" will be
printed, but it's not correct. It's the name of '.symtab' section.

2) readelf -sW xxx does not print anything, while binutils does:

The reason is simple, 'W' section is not found in the binary. I would recommend
printing a warning:

./src/readelf -sW /home/marxin/Programming/linux/arch/x86/kernel/head_64.o
WARNING: cannot find section: 'W'
WARNING: cannot find section: 'W'

You are on the CC list for the bug.
  

Comments

mliska at suse dot cz Oct. 24, 2022, 12:29 p.m. UTC | #1
https://sourceware.org/bugzilla/show_bug.cgi?id=29719

--- Comment #1 from Martin Liska <mliska at suse dot cz> ---
3) we may want to implement the semantic: dump all symbols that live in a given
section "foo". Can be handy for sections like .hot.text and so on.
  
mliska at suse dot cz Oct. 30, 2022, 12:52 a.m. UTC | #2
https://sourceware.org/bugzilla/show_bug.cgi?id=29719

Mark Wielaard <mark at klomp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mark at klomp dot org

--- Comment #2 from Mark Wielaard <mark at klomp dot org> ---
I like the WARNING idea. This would also help with something like:
$ eu-readelf --symbols=.dynsyms /bin/bash
Which currently says nothing, but should warn (it is .dynsym without the s).
  
mliska at suse dot cz Nov. 15, 2022, 4:12 p.m. UTC | #3
https://sourceware.org/bugzilla/show_bug.cgi?id=29719

--- Comment #3 from Martin Liska <mliska at suse dot cz> ---
(In reply to Mark Wielaard from comment #2)
> I like the WARNING idea. This would also help with something like:
> $ eu-readelf --symbols=.dynsyms /bin/bash
> Which currently says nothing, but should warn (it is .dynsym without the s).

Great, can you please take the suggested patch and add a test-case for it?
Thanks.
  
mliska at suse dot cz Nov. 25, 2022, 1:31 p.m. UTC | #4
https://sourceware.org/bugzilla/show_bug.cgi?id=29719

Martin Liska <mliska at suse dot cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at sourceware dot org   |mliska at suse dot cz

--- Comment #4 from Martin Liska <mliska at suse dot cz> ---
I finished the patch:
https://sourceware.org/pipermail/elfutils-devel/2022q4/005607.html
  
mliska at suse dot cz Nov. 28, 2022, 9:59 a.m. UTC | #5
https://sourceware.org/bugzilla/show_bug.cgi?id=29719

Martin Liska <mliska at suse dot cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #5 from Martin Liska <mliska at suse dot cz> ---
Fixed with 2e42dc4328a8944263711ae23b1a34f7f47cb37c.
  

Patch

diff --git a/src/readelf.c b/src/readelf.c
index a206e60e..465526c4 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -2431,6 +2431,7 @@  print_symtab (Ebl *ebl, int type)
   /* Find the symbol table(s).  For this we have to search through the
      section table.  */
   Elf_Scn *scn = NULL;
+  bool symtab_handled = false;

   while ((scn = elf_nextscn (ebl->elf, scn)) != NULL)
     {
@@ -2466,8 +2467,13 @@  print_symtab (Ebl *ebl, int type)
                            elf_ndxscn (scn), elf_errmsg (-1));
            }
          handle_symtab (ebl, scn, shdr);
+         symtab_handled = true;
        }
     }
+
+  if (!symtab_handled && symbol_table_section != NULL)
+    printf ("WARNING: %s: '%s'\n", _("cannot find section"),
+           symbol_table_section);
 }

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