Should elf/tst-dlopen-aout.c fail when compiled as PIE?

  Hi Pail,

You are the author of elf/tst-dlopen-aout.c.  Should it fail
when it is compiled as PIE?  With this patch:


 selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null)

I got

[hjl@gnu-6 build-x86_64-linux]$ ./elf/tst-dlopen-aout
dlopen unexpectedly succeeded
[hjl@gnu-6 build-x86_64-linux]$
  

It's clear from the content of the test that it cannot test what it's
intended to test unless the file it passes to dlopen it an ET_EXEC.  So if
you want to build the test itself as PIE, then you need to change it to
open some file other than itself.
  

On Fri, Mar 6, 2015 at 3:00 PM, Roland McGrath <roland@hack.frob.com> wrote:
> It's clear from the content of the test that it cannot test what it's
> intended to test unless the file it passes to dlopen it an ET_EXEC.  So if
> you want to build the test itself as PIE, then you need to change it to
> open some file other than itself.

Thanks.  I will handle it properly.
  

On Fri, Mar 6, 2015 at 3:05 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Mar 6, 2015 at 3:00 PM, Roland McGrath <roland@hack.frob.com> wrote:
>> It's clear from the content of the test that it cannot test what it's
>> intended to test unless the file it passes to dlopen it an ET_EXEC.  So if
>> you want to build the test itself as PIE, then you need to change it to
>> open some file other than itself.
>
> Thanks.  I will handle it properly.

I think adding

  CFLAGS-tst-dlopen-aout.c += -fno-pie

or some such may be the right fix.

You want to have ET_EXEC, and it's easiest to guarantee ET_EXEC if you
build it yourself, and the test itself will make a good ET_EXEC to
test with -- no reason to build an extra ET_EXEC.
  

On 06 Mar 2015 15:21, Paul Pluzhnikov wrote:
> On Fri, Mar 6, 2015 at 3:05 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > On Fri, Mar 6, 2015 at 3:00 PM, Roland McGrath <roland@hack.frob.com> wrote:
> >> It's clear from the content of the test that it cannot test what it's
> >> intended to test unless the file it passes to dlopen it an ET_EXEC.  So if
> >> you want to build the test itself as PIE, then you need to change it to
> >> open some file other than itself.
> >
> > Thanks.  I will handle it properly.
> 
> I think adding
> 
>   CFLAGS-tst-dlopen-aout.c += -fno-pie
> 
> or some such may be the right fix.

it should be fine to compile as PIE as long as the final link isn't:
	LDFLAGS-tst-dlopen-aout.c = -no-pie
-mike