Backtrace_symbols and .symtab

[Yury Gribov]

On 10/22/2014 06:53 PM, Yury Gribov wrote:
> Hi all,
>
> Current backtrace_symbols(3) tries to read names of functions in call
> stack from .dynsym which is usually very sparse compared to ordinary
> symbol table in .symtab. Even if application is linked with -rdynamic
> (which may be undesirable due to pollution of dynamic namespace, etc.),
> .dynsym won't contain static functions, etc.
>
> Has anyone considered making backtrace_symbols more .symtab-friendly
> e.g. allowing users to prefer .symtab to .dynsym if it's available (*)?
> This would of course be less (probably much less) efficient because
> .symtab search would be linear (compared to hash table available for
> .dynsym) but I can imagine usecases where this would be acceptable e.g.
> printing friendly backtraces on error. AFAIK currently some projects
> link against libunwind and elfutils for the sole purpose of getting
> readable backtraces which should be available with glibc.
>
> -Y
>
> (*) ./elf/sprof.c already does something like this.
>

Cc-ed Andreas (though he has just announced that he won't work on glibc 
anymore...).

-Y