[gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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I have the following situation:
- a package (valgrind) that can be compiled with PIE and uses PIE
  for some purpose or other if it is supported
- tests (make check) that cannot be compiled with PIE

In the upstream release CFLAGS is reset to "-Wno-long-long", but I would
prefer to allow customised CFLAGS. I already asked the developers why
they reset the CFLAGS, but I haven't received an answer.
I made a small modification to configure to enable the use of make.conf's 
CFLAGS, but now some problems occur. The first problem is a problem even
without this modification.

If compiled with the hardened gcc profile, -fno-pie has to be specified
when compiling the tests or it will fail. Specifying -fno-pie always
will force me to disable any PIE support through configure as well.

I tried to adapt the makefiles to disable pie themselves for the tests
only, but then I have another problem:

What if the user specifies -fpie in make.conf? 
The compilation of the tests will fail because -fpie (from the environment) 
will end up in CFLAGS after -fno-pie (from the makefile).
If I use flag-o-matic to filter out -fpie, it will add -fno-pie everywhere
and disable PIE altogether.

I'm looking for a solution that preferably:
- uses (some of) make.conf's CFLAGS
- compiles with all gcc profiles and all CFLAGS (filtering some is ok)
- does not disable PIE altogether

Is there such a solution?

Maurice.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Daniel Ostrow]

On Tue, 2005-04-12 at 17:59 +0200, Maurice van der Pot wrote:
*snip*
> If compiled with the hardened gcc profile, -fno-pie has to be specified
> when compiling the tests or it will fail. Specifying -fno-pie always
> will force me to disable any PIE support through configure as well.
> 
> I tried to adapt the makefiles to disable pie themselves for the tests
> only, but then I have another problem:
*snip*

Take a look at dev-libs/glib/files/glib-2.6.3-testglib-ssp.patch to see
how solar and I dealt with a similar issue with tests and ssp. See if
you can adapt it, we just forced -fno-stack-protector after the CFLAGS
pulled in from the system.

--Dan

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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Mike Frysinger]

On Tuesday 12 April 2005 11:59 am, Maurice van der Pot wrote:
> I have the following situation:
> - a package (valgrind) that can be compiled with PIE and uses PIE
>   for some purpose or other if it is supported
> - tests (make check) that cannot be compiled with PIE

allowing user specified tests for `make check` doesnt really make much sense 
and in fact it's probably a better idea to prevent user CFLAGS from being 
used during `make check`
-mike
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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Tue, Apr 12, 2005 at 01:52:05PM -0400, Mike Frysinger wrote:
> On Tuesday 12 April 2005 11:59 am, Maurice van der Pot wrote:
> > I have the following situation:
> > - a package (valgrind) that can be compiled with PIE and uses PIE
> >   for some purpose or other if it is supported
> > - tests (make check) that cannot be compiled with PIE
> 
> allowing user specified tests for `make check` doesnt really make much sense 

'user specified tests'?? The tests are part of valgrind, they just can't
be compiled with PIE.

> and in fact it's probably a better idea to prevent user CFLAGS from being 
> used during `make check`

In theory, you're probably right. But would you really spend time on
disabling user CFLAGS for make check? How many ebuilds are doing this
right now anyway?

Maurice.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Mike Frysinger]

On Tuesday 12 April 2005 02:20 pm, Maurice van der Pot wrote:
> On Tue, Apr 12, 2005 at 01:52:05PM -0400, Mike Frysinger wrote:
> > On Tuesday 12 April 2005 11:59 am, Maurice van der Pot wrote:
> > > I have the following situation:
> > > - a package (valgrind) that can be compiled with PIE and uses PIE
> > >   for some purpose or other if it is supported
> > > - tests (make check) that cannot be compiled with PIE
> >
> > allowing user specified tests for `make check` doesnt really make much
> > sense
>
> 'user specified tests'?? The tests are part of valgrind, they just can't
> be compiled with PIE.

err s/tests/CFLAGS/

> > and in fact it's probably a better idea to prevent user CFLAGS from being
> > used during `make check`
>
> In theory, you're probably right. But would you really spend time on
> disabling user CFLAGS for make check?

why not ?  you've just shown they break things
src_test() { make check CFLAGS="" || die "make check failed" ; }

> How many ebuilds are doing this  right now anyway?

how many ebuilds' src_test are sensitive user CFLAGS ?  very few i'd say
-mike
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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Tue, Apr 12, 2005 at 12:10:25PM -0400, Daniel Ostrow wrote:
> Take a look at dev-libs/glib/files/glib-2.6.3-testglib-ssp.patch to see
> how solar and I dealt with a similar issue with tests and ssp. See if
> you can adapt it, we just forced -fno-stack-protector after the CFLAGS
> pulled in from the system.

Thanks for the tip. It was perfectly applicable.

Maurice.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Tue, Apr 12, 2005 at 12:10:25PM -0400, Daniel Ostrow wrote:
> 
> Take a look at dev-libs/glib/files/glib-2.6.3-testglib-ssp.patch to see
> how solar and I dealt with a similar issue with tests and ssp. See if
> you can adapt it, we just forced -fno-stack-protector after the CFLAGS
> pulled in from the system.
> 

Ok, so I thought it was all well and good, but now a bug report made me
realise that gcc < 3.4 doesn't have -fpie/-fno-pie.

Here's the problem:
1) valgrind has some features that only work with -fpie
2) valgrind's tests fail to build with -fpie
3) because of the hardened gcc profile, valgrind's tests need -fno-pie
4) simply patching some makefiles to add -fno-pie for tests is not
   possible because gcc < 3.4 doesn't support -fno-pie
5) having the valgrind developers modify their configure/makefiles to
   add -fno-pie for tests in case gcc supports it is not enough, because
   user CFLAGS are appended and CFLAGS in make.conf may contain -fpie
6) using filter-flags to get rid of -fpie in user's CFLAGS actually
   adds -fno-pie and disables features referred to in 1)

What do I do now? 

Why is -fno-pie being added by filter-flags anyway? 

Maurice.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Mike Frysinger]

On Friday 15 April 2005 03:27 pm, Maurice van der Pot wrote:
> Ok, so I thought it was all well and good, but now a bug report made me
> realise that gcc < 3.4 doesn't have -fpie/-fno-pie.

uhh, gcc-3.3.x should certainly support -fpie and -fno-pie

works on my 3.3.5.2005xxxx on amd64 ...
-mike
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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Stephen Bennett]

On Fri, 2005-04-15 at 21:27 +0200, Maurice van der Pot wrote:
> What do I do now? 

The obvious course of action would be to test whether the GCC being used
supports -fno-pie and add it if it does. If it doesn't, you'd just have
to assume that PIE isn't being used by default.

> Why is -fno-pie being added by filter-flags anyway? 

Because with hardened gcc profiles PIE is the default behaviour. So, if
something doesn't work with pie (which is usually why one would filter
out -fpie), we need to add -fno-pie.

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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Fri, Apr 15, 2005 at 08:40:55PM +0100, Stephen Bennett wrote:
> > Why is -fno-pie being added by filter-flags anyway? 
> 
> Because with hardened gcc profiles PIE is the default behaviour. So, if
> something doesn't work with pie (which is usually why one would filter
> out -fpie), we need to add -fno-pie.

That's not filtering, that's inverting. In this case I need filtering. 
I can try to get the developers to change their makefiles, but none of
that would help if I can't get -fpie and -fno-pie out of the user's
CFLAGS.

I could of course close any bugs that I would get because of these
CFLAGS as invalid and suggest they use the appropriate gcc profile 
instead.

Would that be reasonable?

Maurice.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Fri, Apr 15, 2005 at 03:38:04PM -0400, Mike Frysinger wrote:
> uhh, gcc-3.3.x should certainly support -fpie and -fno-pie

In that case, take a look at
http://bugs.gentoo.org/show_bug.cgi?id=89179.

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Mike Frysinger]

On Friday 15 April 2005 03:55 pm, Maurice van der Pot wrote:
> On Fri, Apr 15, 2005 at 03:38:04PM -0400, Mike Frysinger wrote:
> > uhh, gcc-3.3.x should certainly support -fpie and -fno-pie
>
> In that case, take a look at
> http://bugs.gentoo.org/show_bug.cgi?id=89179.

it's because he has USE=boundschecking ... in that case, it's Not Your 
Problem :)

mark it a dupe of Bug 86860 where i'm handling this issue and forgot your 
users ever complained !
-mike
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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Vibhav Garg]

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Maurice van der Pot wrote:
> On Tue, Apr 12, 2005 at 12:10:25PM -0400, Daniel Ostrow wrote:
> 
>>Take a look at dev-libs/glib/files/glib-2.6.3-testglib-ssp.patch to see
>>how solar and I dealt with a similar issue with tests and ssp. See if
>>you can adapt it, we just forced -fno-stack-protector after the CFLAGS
>>pulled in from the system.
>>
> 
> 
> Ok, so I thought it was all well and good, but now a bug report made me
> realise that gcc < 3.4 doesn't have -fpie/-fno-pie.
> 
> Here's the problem:
> 1) valgrind has some features that only work with -fpie
> 2) valgrind's tests fail to build with -fpie
> 3) because of the hardened gcc profile, valgrind's tests need -fno-pie
> 4) simply patching some makefiles to add -fno-pie for tests is not
>    possible because gcc < 3.4 doesn't support -fno-pie
> 5) having the valgrind developers modify their configure/makefiles to
>    add -fno-pie for tests in case gcc supports it is not enough, because
>    user CFLAGS are appended and CFLAGS in make.conf may contain -fpie
> 6) using filter-flags to get rid of -fpie in user's CFLAGS actually
>    adds -fno-pie and disables features referred to in 1)
> 
> What do I do now? 
> 
> Why is -fno-pie being added by filter-flags anyway? 
> 
> Maurice.
> 
Sorry for the dumb question but was do -fpie and -fno-pie do?

Vibhav
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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Maurice van der Pot]

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On Fri, Apr 15, 2005 at 04:05:16PM -0400, Mike Frysinger wrote:
> On Friday 15 April 2005 03:55 pm, Maurice van der Pot wrote:
> > On Fri, Apr 15, 2005 at 03:38:04PM -0400, Mike Frysinger wrote:
> > > uhh, gcc-3.3.x should certainly support -fpie and -fno-pie
> >
> > In that case, take a look at
> > http://bugs.gentoo.org/show_bug.cgi?id=89179.
> 
> it's because he has USE=boundschecking ... in that case, it's Not Your 
> Problem :)
> 
> mark it a dupe of Bug 86860 where i'm handling this issue and forgot your 
> users ever complained !
> -mike

Cool, all not masked gcc's support the flags I need. Guess I have Friday
night off after all.

Thanks Mike!

-- 
Maurice van der Pot

Gentoo Linux Developer   griffon26@gentoo.org     http://www.gentoo.org
Creator of BiteMe!       griffon26@kfk4ever.com   http://www.kfk4ever.com


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Re: [gentoo-dev] What to do with things like -fpie in CFLAGS in environment?

[Mike Frysinger]

On Friday 15 April 2005 04:13 pm, Vibhav Garg wrote:
> Sorry for the dumb question but was do -fpie and -fno-pie do?

yeah you should be sorry !

seriously though, PIE stands for Position Independent Executables and -fpie / 
-fno-pie controls whether the toolchain produces PIE (mmm PIE)

for something less vague, try this page:
http://hardened.gentoo.org/pie-ssp.xml
-mike
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