[PATCH] gold: Set DF_1_PIE for -pie

[PATCH] gold: Set DF_1_PIE for -pie

[Fangrui Song]

DF_1_PIE originated from Solaris.
GNU ld since 5fe2850dd96483f176858fd75c098313d5b20bc2
sets the flag on non-Solaris platforms.

It can help distinguish PIE from ET_DYN.
eu-classify from elfutils uses this flag to recognize PIE.
glibc uses this flag to reject dlopen'ing a PIE (PR glibc/24323).

	PR gold/26039
	* layout.cc (Layout::finish_dynamic_section): Set DF_1_PIE.

	elfcpp/
	* elfcpp.h (enum DF_1): New enum member DF_1_PIE.
---
 elfcpp/elfcpp.h | 3 ++-
 gold/layout.cc  | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
index 339faadaf3..a1d0090ab6 100644
--- a/elfcpp/elfcpp.h
+++ b/elfcpp/elfcpp.h
@@ -913,7 +913,8 @@ enum DF_1
   DF_1_INTERPOSE = 0x400,
   DF_1_NODEFLIB = 0x800,
   DF_1_NODUMP = 0x1000,
-  DF_1_CONLFAT = 0x2000
+  DF_1_CONLFAT = 0x2000,
+  DF_1_PIE = 0x08000000,
 };
 
 // Version numbers which appear in the vd_version field of a Verdef
diff --git a/gold/layout.cc b/gold/layout.cc
index be437f3900..ee75c50cad 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -5351,6 +5351,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
     flags |= elfcpp::DF_1_NOW;
   if (parameters->options().Bgroup())
     flags |= elfcpp::DF_1_GROUP;
+  if (parameters->options().pie())
+    flags |= elfcpp::DF_1_PIE;
   if (flags != 0)
     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
 }
-- 
2.27.0.rc0.183.gde8f92d652-goog

Re: [PATCH] gold: Set DF_1_PIE for -pie

[Fangrui Song]

Drop incorrect CCes...  Sorry, in my git-send-email command

git send-email --to binutils@sourceware.org --to 'Cary Coutant <hidden>' --cc 'Pedro Alves hidden' --validate 0001-gold-Set-DF_1_PIE-for-pie.patch

I forgot to quote Pedro's address with < >

On 2020-05-30, Fangrui Song wrote:
>DF_1_PIE originated from Solaris.
>GNU ld since 5fe2850dd96483f176858fd75c098313d5b20bc2
>sets the flag on non-Solaris platforms.
>
>It can help distinguish PIE from ET_DYN.
>eu-classify from elfutils uses this flag to recognize PIE.
>glibc uses this flag to reject dlopen'ing a PIE (PR glibc/24323).
>
>	PR gold/26039
>	* layout.cc (Layout::finish_dynamic_section): Set DF_1_PIE.
>
>	elfcpp/
>	* elfcpp.h (enum DF_1): New enum member DF_1_PIE.
>---
> elfcpp/elfcpp.h | 3 ++-
> gold/layout.cc  | 2 ++
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
>diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
>index 339faadaf3..a1d0090ab6 100644
>--- a/elfcpp/elfcpp.h
>+++ b/elfcpp/elfcpp.h
>@@ -913,7 +913,8 @@ enum DF_1
>   DF_1_INTERPOSE = 0x400,
>   DF_1_NODEFLIB = 0x800,
>   DF_1_NODUMP = 0x1000,
>-  DF_1_CONLFAT = 0x2000
>+  DF_1_CONLFAT = 0x2000,
>+  DF_1_PIE = 0x08000000,
> };
>
> // Version numbers which appear in the vd_version field of a Verdef
>diff --git a/gold/layout.cc b/gold/layout.cc
>index be437f3900..ee75c50cad 100644
>--- a/gold/layout.cc
>+++ b/gold/layout.cc
>@@ -5351,6 +5351,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
>     flags |= elfcpp::DF_1_NOW;
>   if (parameters->options().Bgroup())
>     flags |= elfcpp::DF_1_GROUP;
>+  if (parameters->options().pie())
>+    flags |= elfcpp::DF_1_PIE;
>   if (flags != 0)
>     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
> }
>-- 
>2.27.0.rc0.183.gde8f92d652-goog
>

Re: [PATCH] gold: Set DF_1_PIE for -pie

[Cary Coutant]

> >       PR gold/26039
> >       * layout.cc (Layout::finish_dynamic_section): Set DF_1_PIE.
> >
> >       elfcpp/
> >       * elfcpp.h (enum DF_1): New enum member DF_1_PIE.

This is OK. Thanks!


-cary

Re: [PATCH] gold: Set DF_1_PIE for -pie

[Fāng-ruì Sòng]

On Sat, Jun 13, 2020 at 5:30 PM Cary Coutant <ccoutant@gmail.com> wrote:
>
> > >       PR gold/26039
> > >       * layout.cc (Layout::finish_dynamic_section): Set DF_1_PIE.
> > >
> > >       elfcpp/
> > >       * elfcpp.h (enum DF_1): New enum member DF_1_PIE.
>
> This is OK. Thanks!
>
>
> -cary

Great! Can you please commit it on my behalf? I don't have a write access.