dtrace discuss - Oct 2008 - Why could I get function names from a stripped exec?

Hello, all experts.
When I use pid provider, my Dscript with -F option output the codepath with
flowindent as you know,

e.g. 
 -> main
    -> f1
        -> f2

however I realized that the exec file I used at that time was stripped.
Does anyone know the reason why I could see the function names?

Thanks in advance.
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This message posted from opensolaris.org

I guess it''s from CTF?
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This message posted from opensolaris.org

Yasufumi CHIDA wrote:
> Hello, all experts.
> When I use pid provider, my Dscript with -F option output the codepath with
flowindent as you know,
> 
> e.g. 
>  -> main
>     -> f1
>         -> f2
> 
> however I realized that the exec file I used at that time was stripped.
> Does anyone know the reason why I could see the function names?
Probably the dynamic info, but, are you just asking for curiosity''s
sake, or is
there a problem?

Thanks.

To tell the truth, I''m an instructor, so I have to reply to my
trainees.
Of course I''m curious about the internal working of DTrace.



BTW, you said "dynamic info", what is this on earth?

Yasufumi.
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This message posted from opensolaris.org

Yasufumi CHIDA wrote:
> Hello, all experts.
> When I use pid provider, my Dscript with -F option output the codepath with
flowindent as you know,
> 
> e.g. 
>  -> main
>     -> f1
>         -> f2
> 
> however I realized that the exec file I used at that time was stripped.
> Does anyone know the reason why I could see the function names?
> 
> Thanks in advance.
> --
> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org

Are you using Nevada or OpenSolaris? If so, they''re probably
coming from the .SUNW_ldynsym section. Test for it like this:

	% elfdump -c -N.SUNW_ldynsym /bin/ls

	Section Header[5]:  sh_name: .SUNW_ldynsym
	    sh_addr:      0x80505fc       sh_flags:   [ SHF_ALLOC ]
	    sh_size:      0x250           sh_type:    [ SHT_SUNW_LDYNSYM ]
	    sh_offset:    0x5fc           sh_entsize: 0x10 (37 entries)
	    sh_link:      7               sh_info:    37
	    sh_addralign: 0x4

If so, you can read more about it here:

	http://blogs.sun.com/ali/entry/what_is_sunw_ldynsym

- Ali

Hi,

Yasufumi CHIDA wrote:
> Thanks.
>
> To tell the truth, I''m an instructor, so I have to reply to my
trainees.
> Of course I''m curious about the internal working of DTrace.
>
>
>
> BTW, you said "dynamic info", what is this on earth?
>   
The names are needed for dynamic linking.  They are in the .dynsym 
section of the file.
You might want to look at elfdump output, then 
http://blogs.sun.com/ali/entry/inside_elf_symbol_tables,
where Ali Bahrami has a decent description.  (Or google for .dynsym, 
which is how I found
Ali''s blog).
max
> Yasufumi.
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>