[v2] mips: pldd: support DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL

  [v2: remove useless typedef, seperate E(r_debug_offset) into a header.]

MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
instead of DT_DEBUG.

Signed-off-by: Xi Ruoyao <xry111@mengyan1223.wang>
---
 elf/pldd-xx.c                     | 34 +++++++++++++++-----------
 sysdeps/generic/elf-pldd-rdebug.h | 26 ++++++++++++++++++++
 sysdeps/mips/elf-pldd-rdebug.h    | 40 +++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+), 14 deletions(-)
 create mode 100644 sysdeps/generic/elf-pldd-rdebug.h
 create mode 100644 sysdeps/mips/elf-pldd-rdebug.h
  

On Fri, Jan 28, 2022 at 1:17 PM Xi Ruoyao <xry111@mengyan1223.wang> wrote:
>
> [v2: remove useless typedef, seperate E(r_debug_offset) into a header.]
>
> MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
> instead of DT_DEBUG.
>
> Signed-off-by: Xi Ruoyao <xry111@mengyan1223.wang>
> ---
>  elf/pldd-xx.c                     | 34 +++++++++++++++-----------
>  sysdeps/generic/elf-pldd-rdebug.h | 26 ++++++++++++++++++++
>  sysdeps/mips/elf-pldd-rdebug.h    | 40 +++++++++++++++++++++++++++++++
>  3 files changed, 86 insertions(+), 14 deletions(-)
>  create mode 100644 sysdeps/generic/elf-pldd-rdebug.h
>  create mode 100644 sysdeps/mips/elf-pldd-rdebug.h
>
> diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
> index 1cdfb49c53..368528371d 100644
> --- a/elf/pldd-xx.c
> +++ b/elf/pldd-xx.c
> @@ -22,6 +22,8 @@
>  #define EW_(e, w, t) EW__(e, w, _##t)
>  #define EW__(e, w, t) e##w##t
>
> +#include <elf-pldd-rdebug.h>

You should drop pldd in filename and also handle tst-dlmopen4.c
in the same header file.

> +
>  struct E(link_map)
>  {
>    EW(Addr) l_addr;
> @@ -126,21 +128,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
>             != p[i].p_filesz)
>           error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
>
> -       /* Search for the DT_DEBUG entry.  */
> +       /* Search for the r_debug struct.  */
>         for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
> -         if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
> -           {
> -             struct E(r_debug) r;
> -             if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
> -                 != sizeof (r))
> -               error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
> -
> -             if (r.r_map != 0)
> -               {
> -                 list = r.r_map;
> -                 break;
> -               }
> -           }
> +         {
> +           EW(Addr) d_addr = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
> +           EW(Addr) off = E(r_debug_offset)(&dyn[j], memfd, d_addr);
> +           if (off != 0)
> +             {
> +               struct E(r_debug) r;
> +               if (pread (memfd, &r, sizeof (r), off)
> +                   != sizeof (r))
> +                 error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
> +
> +               if (r.r_map != 0)
> +                 {
> +                   list = r.r_map;
> +                   break;
> +                 }
> +             }
> +         }
>
>         free (dyn);
>         break;
> diff --git a/sysdeps/generic/elf-pldd-rdebug.h b/sysdeps/generic/elf-pldd-rdebug.h
> new file mode 100644
> index 0000000000..6df651cd55
> --- /dev/null
> +++ b/sysdeps/generic/elf-pldd-rdebug.h
> @@ -0,0 +1,26 @@
> +/* Function to access r_debug structure for pldd.
> +   Copyright (C) 2020-2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +static EW(Addr)
> +E(r_debug_offset) (EW(Dyn) *d, int, EW(Addr))
> +{
> +  if (d->d_tag == DT_DEBUG)
> +    return (EW(Addr)) d->d_un.d_ptr;
> +
> +  return 0;
> +}
> diff --git a/sysdeps/mips/elf-pldd-rdebug.h b/sysdeps/mips/elf-pldd-rdebug.h
> new file mode 100644
> index 0000000000..89a20c191a
> --- /dev/null
> +++ b/sysdeps/mips/elf-pldd-rdebug.h
> @@ -0,0 +1,40 @@
> +/* Function to access r_debug structure for pldd, MIPS specific version.
> +   Copyright (C) 2020-2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +static EW(Addr)
> +E(r_debug_offset) (EW(Dyn) *d, int memfd, EW(Addr) d_addr)
> +{
> +  EW(Addr) ptr;
> +
> +  switch (d->d_tag)
> +    {
> +    case DT_MIPS_RLD_MAP_REL:
> +      ptr = d_addr + d->d_un.d_val;
> +      break;
> +    case DT_MIPS_RLD_MAP:
> +      ptr = d->d_un.d_ptr;
> +      break;
> +    default:
> +      return 0;
> +    }
> +
> +    if (pread (memfd, &ptr, sizeof (ptr), ptr) != sizeof (ptr))
> +      return 0;
> +
> +    return ptr;
> +}
> --
> 2.35.0
>
>