Re: how does ld.so call ELF's entry?

On Sun, Apr 07, 2013 at 06:45:58AM +0200, Sofiane Akermoun wrote:
> EntryPoint is set in the ELF Header at assembling/linking time.

  how does the interpreter know this address?

> 
> 2013/4/7 ishare <[email protected]>:
> > On Sat, Apr 06, 2013 at 08:43:16PM -0700, Chris Evans wrote:
> >> With a far jump to entry offset
> >
> >   How does it know the entry point's address?
> >
> >>
> >>
> >> Sent from my iPad
> >>
> >> On Apr 6, 2013, at 8:39 PM, ishare <[email protected]> wrote:
> >>
> >> > On Sun, Apr 07, 2013 at 05:11:28AM +0200, Sofiane Akermoun wrote:
> >> >> Hello,
> >> >>
> >> >>
> >> >> The interpreter is specified during linking process and the program header
> >> >> of your binary is filled with good values.
> >> >> Then when the operating system load your binary, he finds next the
> >> >> interpreter to use.
> >> >> The linker ld sets the good values by default but you can overwrite it or
> >> >> specify other values if you want.
> >> >> The steps are:
> >> >> 1)The operating system loads your binary
> >> >> 2)The program loader system execute the Interpreter specifiy in the binary
> >> >> 3)The interpreter gather all the dynamic libraries needed in memory
> >> >
> >> >
> >> >> 4)The Control is passed to the entry point of your program
> >> >
> >> >  How does  the step 4 been  done ?
> >> >
> >> >  thanks!
> >> >>
> >> >> The entry point is specified in your code source as a "global". And could
> >> >> be find in your object file by the linker.
> >> >> In theory there are some default tag to specify entry point, like "..start"
> >> >> for nasm, but you can also passed it to the linker.
> >> >>
> >> >> regards,
> >> >>
> >> >> Sofiane Akermoun
> >> >> [email protected]
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >> 2013/4/7 ishare <[email protected]>
> >> >>
> >> >>>
> >> >>>  For an ELF ,which needs a interpreter , how is it  been called by the
> >> >>> interpreter ?
> >> >>>
> >> >>>  As I know the interpreter is loaded first and do something essential
> >> >>> ,then call the main routine of ELF .
> >> >>>  How is this procedure implemented ?
> >> >>>
> >> >>>  Thanks!
> >> >>> --
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> >> >>> in
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> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> Sofiane AKERMOUN
> >> >> [email protected]
> >> > --
> >> > To unsubscribe from this list: send the line "unsubscribe linux-assembly" in
> >> > the body of a message to [email protected]
> >> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > --
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> 
> 
> 
> -- 
> Sofiane AKERMOUN
> [email protected]