[Bug dynamic-link/18422] elf/tst-audit tests fail without PLT entries

[Bug dynamic-link/18422] elf/tst-audit tests fail without PLT entries

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18422

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
The error message was

no PLTREL found in object
/export/build/gnu/glibc-test/build-x86_64-linux/elf/ld.so

since ld.so was built with -z now. After

commit 3e058c9d7eab6d6361e7cda5ba1394bc1757c9f6
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri May 22 17:46:42 2015 -0700

    Don't issue an error if DT_PLTRELSZ is missing

    A shared object doesn't need PLT if there are no PLT relocations.  It
    shouldn't be an error if DT_PLTRELSZ is missing.

      [BZ #18410]
      * elf/dl-reloc.c (_dl_relocate_object): Don't issue an error
      for missing DT_PLTRELSZ.

the error message is gone.  But there is still:

FAIL: elf/tst-audit2

elf/tst-audit2.c has

/* This calloc definition will be called by the dynamic linker itself.
   We test that it has initialized our TLS block by the time it does so.  */

void *
calloc (size_t n, size_t m)
{
  if (magic[0] != MAGIC1 || magic[1] != MAGIC2)
    {
      printf ("{%x, %x} != {%x, %x}\n", magic[0], magic[1], MAGIC1, MAGIC2);
      abort ();
    }
  magic[0] = MAGIC2;
  magic[1] = MAGIC1;

Since ld.so is built with -z now, there are no PLT relocations and this calloc
won't be used:

Relocation section '.rela.dyn' at offset 0x8a8 contains 16 entries:
  Offset          Info           Type           Sym. Value    Sym. Name +
Addend
000000221d48  000000000008 R_X86_64_RELATIVE                    10160
000000221d50  000000000008 R_X86_64_RELATIVE                    f070
000000221d58  000000000008 R_X86_64_RELATIVE                    ee30
000000221d60  000000000008 R_X86_64_RELATIVE                    11410
000000221d68  000000000008 R_X86_64_RELATIVE                    9c10
000000221d70  000000000008 R_X86_64_RELATIVE                    129c0
000000221d78  000000000008 R_X86_64_RELATIVE                    12e20
000000221d80  000000000008 R_X86_64_RELATIVE                    14da0
000000221d88  000000000008 R_X86_64_RELATIVE                    12570
000000221d90  000000000008 R_X86_64_RELATIVE                    16e40
000000221f98  000b00000006 R_X86_64_GLOB_DAT 00000000000170d0
__libc_memalign@@GLIBC_2.2.5 + 0
000000221fa0  001700000006 R_X86_64_GLOB_DAT 00000000000171d0
malloc@@GLIBC_2.2.5 + 0
000000221fa8  000e00000006 R_X86_64_GLOB_DAT 00000000000171e0
calloc@@GLIBC_2.2.5 + 0
000000221fb0  000700000006 R_X86_64_GLOB_DAT 0000000000017390
realloc@@GLIBC_2.2.5 + 0
000000221fb8  000900000006 R_X86_64_GLOB_DAT 0000000000223120
_r_debug@@GLIBC_2.2.5 + 0
000000221fc0  000600000006 R_X86_64_GLOB_DAT 0000000000017220 free@@GLIBC_2.2.5
+ 0

Assuming we do want to keep PLT relocations in ld.so so that malloc functions
in ld.so can be overridden, I don't think ld.so should be built with -z now.
There is no reason to build ld.so with -z now since ld.so is the one doing
BIND_NOW.  The only thing we get with -z now on ld.so is

 0x0000000000000018 (BIND_NOW)           
 0x000000006ffffffb (FLAGS_1)            Flags: NOW

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[Bug dynamic-link/18422] elf/tst-audit tests fail without PLT entries

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=18422

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, hjl/pr18422 has been created
        at  df5dc4f32dc00eecd24534275ad82e1a3b49335a (commit)

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=df5dc4f32dc00eecd24534275ad82e1a3b49335a

commit df5dc4f32dc00eecd24534275ad82e1a3b49335a
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sat May 23 06:05:19 2015 -0700

    Don't build ld.so with -Wl,-z,now

    PLT entries aren't required when -z now used.  Linker on master with:

    commit 25070364b0ce33eed46aa5d78ebebbec6accec7e
    Author: H.J. Lu <hjl.tools@gmail.com>
    Date:   Sat May 16 07:00:21 2015 -0700

        Don't generate PLT relocations for now binding

        There is no need for PLT relocations with -z now. We can use GOT
        relocations, which take less space, instead and replace 16-byte .plt
        entres with 8-byte .plt.got entries.

        bfd/

          * elf32-i386.c (elf_i386_check_relocs): Create .plt.got section
          for now binding.
          (elf_i386_allocate_dynrelocs): Use .plt.got section for now
          binding.
          * elf64-x86-64.c (elf_x86_64_check_relocs): Create .plt.got
          section for now binding.
          (elf_x86_64_allocate_dynrelocs): Use .plt.got section for now
          binding.

    won't generate PLT entries with -z now.  elf/tst-audit2.c has

    /* This calloc definition will be called by the dynamic linker itself.
       We test that it has initialized our TLS block by the time it does so.
    */

    void *
    calloc (size_t n, size_t m)
    {
      if (magic[0] != MAGIC1 || magic[1] != MAGIC2)
        {
          printf ("{%x, %x} != {%x, %x}\n", magic[0], magic[1], MAGIC1,
MAGIC2);
          abort ();
        }
      magic[0] = MAGIC2;
      magic[1] = MAGIC1;

    Since ld.so is built with -z now, there are no PLT relocations and this
    calloc won't be used:

    Relocation section '.rela.dyn' at offset 0x66c contains 16 entries:
     Offset     Info    Type            Sym.Value  Sym. Name + Addend
    00222e88  00000008 R_X86_64_RELATIVE            10970
    00222e8c  00000008 R_X86_64_RELATIVE            f8f0
    00222e90  00000008 R_X86_64_RELATIVE            f6c0
    00222e94  00000008 R_X86_64_RELATIVE            11bd0
    00222e98  00000008 R_X86_64_RELATIVE            a1b0
    00222e9c  00000008 R_X86_64_RELATIVE            130c0
    00222ea0  00000008 R_X86_64_RELATIVE            13c50
    00222ea4  00000008 R_X86_64_RELATIVE            15fc0
    00222ea8  00000008 R_X86_64_RELATIVE            12cd0
    00222eac  00000008 R_X86_64_RELATIVE            17f90
    00222fbc  00000a06 R_X86_64_GLOB_DAT 00018230      
__libc_memalign@@GLIBC_2.16 + 0
    00222fc4  00001506 R_X86_64_GLOB_DAT 00018300   malloc@@GLIBC_2.16 + 0
    00222fcc  00000d06 R_X86_64_GLOB_DAT 00018310   calloc@@GLIBC_2.16 + 0
    00222fd4  00000506 R_X86_64_GLOB_DAT 000184a0   realloc@@GLIBC_2.16 + 0
    00222fdc  00000706 R_X86_64_GLOB_DAT 002239a0   _r_debug@@GLIBC_2.16 + 0
    00222fe4  00000406 R_X86_64_GLOB_DAT 00018340   free@@GLIBC_2.16 + 0

    Assuming we do want to keep PLT relocations in ld.so so that malloc
    functions in ld.so can be overridden, ld.so should be built with -z now.
    There is no reason to build ld.so with -z now since ld.so is the one
    doing BIND_NOW.  The only thing we get with -z now on ld.so is DT tag:

     0x0000000000000018 (BIND_NOW)
     0x000000006ffffffb (FLAGS_1)            Flags: NOW

    This patch removes -Wl,-z,now from ld.so build.

        [BZ #18422]
        * elf/Makefile (z-now-yes): Removed.
        ($(objpfx)ld.so): Remove $(z-now-$(bind-now)).

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[Bug dynamic-link/18422] elf/tst-audit tests fail without PLT entries

[cvs-commit at gcc dot gnu.org]

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https://sourceware.org/bugzilla/show_bug.cgi?id=18422

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, master has been updated
       via  58007e9e68913290b1f4f73afc1055f779a8ed5d (commit)
      from  be2e25bbd78f9fdf27bed254d02915d019c5b363 (commit)

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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=58007e9e68913290b1f4f73afc1055f779a8ed5d

commit 58007e9e68913290b1f4f73afc1055f779a8ed5d
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu May 28 05:06:27 2015 -0700

    Make sure that calloc is called at least once

    PLT relocations aren't required when -z now used.  Linker on master with:

    commit 25070364b0ce33eed46aa5d78ebebbec6accec7e
    Author: H.J. Lu <hjl.tools@gmail.com>
    Date:   Sat May 16 07:00:21 2015 -0700

        Don't generate PLT relocations for now binding

        There is no need for PLT relocations with -z now. We can use GOT
        relocations, which take less space, instead and replace 16-byte .plt
        entres with 8-byte .plt.got entries.

        bfd/

          * elf32-i386.c (elf_i386_check_relocs): Create .plt.got section
          for now binding.
          (elf_i386_allocate_dynrelocs): Use .plt.got section for now
          binding.
          * elf64-x86-64.c (elf_x86_64_check_relocs): Create .plt.got
          section for now binding.
          (elf_x86_64_allocate_dynrelocs): Use .plt.got section for now
          binding.

    won't generate PLT relocations with -z now.  elf/tst-audit2.c expect
    certain order of execution in ld.so. �With PLT relocations, the GOTPLT
    entry of calloc is update to calloc defined in tst-audit2:

    (gdb) bt
    � � skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
    � � version=<optimized out>, sym=<optimized out>, map=<optimized out>)
    � � at ../sysdeps/i386/dl-machine.h:329
    out>,
    � � nrelative=<optimized out>, relsize=<optimized out>,
    � � reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
    reloc_mode=reloc_mode@entry=0,
    � � consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
    � � user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
    � � start_argptr=start_argptr@entry=0xffffcfb0,
    � � dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
    ../elf/dl-sysdep.c:249
    � �from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
    (gdb)

    and then calloc is called:

    (gdb) c
    Continuing.

    Breakpoint 4, calloc (n=n@entry=20, m=4) at tst-audit2.c:18
    18 {
    (gdb) bt
    � � reloc_mode=reloc_mode@entry=0, consider_profiling=1,
    � � consider_profiling@entry=0) at dl-reloc.c:272
    � � user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
    � � start_argptr=start_argptr@entry=0xffffcfb0,
    � � dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
    ../elf/dl-sysdep.c:249
    � �from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
    (gdb)

    With GOT relocation, calloc in ld.so is called first:

    (gdb) bt
    � � consider_profiling=1) at dl-reloc.c:272
    � � user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2074
    � � start_argptr=start_argptr@entry=0xffffcfa0,
    � � dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
    ../elf/dl-sysdep.c:249
    � �from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
    (gdb)

    and then the GOT entry of calloc is updated:

    (gdb) bt
    � � skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
    � � version=<optimized out>, sym=<optimized out>, map=<optimized out>)
    � � at ../sysdeps/i386/dl-machine.h:329
    out>,
    � � nrelative=<optimized out>, relsize=<optimized out>,
    � � reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
    reloc_mode=reloc_mode@entry=0,
    � � consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
    � � user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2133
    � � start_argptr=start_argptr@entry=0xffffcfa0,
    � � dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
    ../elf/dl-sysdep.c:249
    � �from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
    (gdb)

    After that, since calloc isn't called from ld.so nor any other modules,
    magic in tst-audit2 isn't updated. �Both orders are correct.  This patch
    makes sure that calloc in tst-audit2.c is called at least once from ld.so.

        [BZ #18422]
        * Makefile ($(objpfx)tst-audit2): Depend on $(libdl).
        ($(objpfx)tst-audit2.out): Also depend on
        $(objpfx)tst-auditmod9b.so.
        * elf/tst-audit2.c: Include <dlfcn.h>.
        (calloc_called): New.
        (calloc): Allow to be called more than once.
        (do_test): dllopen/dlclose $ORIGIN/tst-auditmod9b.so.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog        |   11 +++++++++++
 NEWS             |    2 +-
 elf/Makefile     |    3 ++-
 elf/tst-audit2.c |   26 ++++++++++++++++++++------
 4 files changed, 34 insertions(+), 8 deletions(-)

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Subject: [Bug libc/17841] Build failure if compiler defaults to PIE
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https://sourceware.org/bugzilla/show_bug.cgi?id\x17841

--- Comment #10 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, hjl/pr17841/master has been created
        at  1d998c5c0908184168789d701d68186217a623be (commit)

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h\x1d998c5c0908184168789d701d68186217a623be

commit 1d998c5c0908184168789d701d68186217a623be
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Mar 2 14:53:11 2015 -0800

    Compile archives with -fno-pie

    When compiler defaults to PIE, we compile archives with -fno-pie.   Since
    archives won't be used with PIE, compile them with -fpie isn't necessary.

        [BZ #17841]
        * Makeconfig (no-pie-ccflag): New.  Set to -fno-pie.
        (pic-default): Don't define if $(no-pie-ccflag) is -fno-pie.
        (test-object-suffix): New.
        * Makerules (archive-objects): New.  Set before including
        extra-lib.mk.
        ($(archive-objects)): New. New rule to append $(no-pie-ccflag)
        to CFLAGS.
        * extra-lib.mk (archive-objects): New.
        * crypt/Makefile ($(objpfx)md5test): Replace ".o" with
        $(test-object-suffix).
        ($(objpfx)md5test-giant): Likewise.
        ($(objpfx)sha256test): Likewise.
        ($(objpfx)sha512test): Likewise.
        * math/Makefile (LDFLAGS-atest-exp): New.
        (LDFLAGS-atest-sincos): Likewise.
        (LDFLAGS-atest-exp2): Likewise.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;hÀ3fb5f075b58541f5ae6815e27e552d8c4c4c4c

commit c03fb5f075b58541f5ae6815e27e552d8c4c4c4c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Jan 14 06:29:04 2015 -0800

    Support compilers defaulting to PIE

    If PIE is the default, we need to build programs as PIE.

        [BZ #17841]
        * Makeconfig (no-pie-ldflag): New.
        (+link): Set to $(+link-pie) if default to PIE.
        (+link-tests): Set to $(+link-pie-tests) if default to PIE.
        * config.make.in (build-pie-default): New.
        * configure.ac (libc_cv_pie_default): New.  Set to yes if -fPIE
        is default.  AC_SUBST.
        * configure: Regenerated.
        * elf/Makefile (LDFLAGS-tst-dlopen-aout): New.

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[Bug dynamic-link/18422] elf/tst-audit tests fail without PLT entries

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18422

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |2.22

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed.

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