Re: polyorb build ok with gnat-4.9

[Nicolas Boulenguez <nicolas.boulenguez@free.fr>]

On Fri, Feb 21, 2014 at 03:25:26PM +0100, Xavier Grave wrote:

> Although I have this in my gnatmake command line: -Wl,-z,relro I
> still have this lintian warning and get back at [3] with
> hardening-no-relro
> [3] https://lists.debian.org/debian-ada/2012/05/msg00016.html

# /usr/bin/hardening-check -v ELF_OBJECT reports the faulty
functions. I have seen strcpy reported in an object compiled from pure
Ada code, so a deeper explanation is needed, but this is quite rare.

However, the most probable cause is an incorrect advice in [3] :-).
In library project files:
* Library_Options are used when linking the dynamic library object
  after compilation. The value, if any, looks like
  LDFLAGS+LDLIBS=-Wl,-z,relro -Wl,--as-needed -lfoo -lbar.  It is
  ignored during static builds.  Its little brother
  Leading_Library_Options may work around some corner cases.
* Linker.Default_Switches ("Ada") in Linker package are used later
  when linking another object depending on the library. The value, if
  any, generally looks like LDLIBS=-lfoo -lbar.  It is ignored when
  linking the library itself after compilation.

Replace the project file in [3] with:

library project Foo is
  Ldlibs := External_As_List ("LDLIBS", " ");
  type Library_Kind is ("dynamic", "static");
  Kind : Library_Kind := External ("KIND");
  for Library_Name use Project'Name;
  case Kind is
     when "dynamic" =>
        for Library_Version use "lib" & Project'Library_Name & ".so."
          & External ("SOVERSION");
        --  Build-time options use to link the shared library.
        for Library_Options use External_As_List ("LDFLAGS", " ")
                              & Ldlibs;
     when "static" =>
        null;
  end case;
  for Library_Kind use Kind;
  for Library_Dir use "build-lib-" & Kind;
  for Object_Dir use "build-obj-" & Kind;
  package Linker is
     --  This package only exists to pass more options to importing
     --  projects like demo/demo.gpr.
     for Linker_Options use Ldlibs;
  end Linker;
  package Compiler is
     for Default_Switches ("Ada") use External_As_List ("ADAFLAGS", " ");
     for Default_Switches ("C") use External_As_List ("CPPFLAGS", " ")
                                  & External_As_List ("CFLAGS", " ");
  end Compiler;
  --  This is needed so that gnatmake embeds .o files generated from .c sources,
  --  even if it does not know how to compile them on its own.
  for Languages use ("Ada", "C");
  for Source_Dirs use ("src");
end Foo;

Dh_ada_library with then generate the packaged project, copying any -l
option from the Linker_Options of the dynamic build project into the
Linker.Default_Switches of the packaged project.