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elf: Add <dl-r_debug.h> 

Add <dl-r_debug.h> to get the adddress of the r_debug structure after
relocation and its offset before relocation from the PT_DYNAMIC segment
to support DT_DEBUG, DT_MIPS_RLD_MAP_REL and DT_MIPS_RLD_MAP.

Co-developed-by: Xi Ruoyao <xry111@mengyan1223.wang>
This commit is contained in:
H.J. Lu 2022-01-29 10:56:45 -08:00
parent 829ea0caca
commit 3fb18fd80c
4 changed files with 123 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
elf/pldd-xx.c
View File

@ -22,6 +22,8 @@
#define EW_(e, w, t) EW__(e, w, _##t)
#define EW__(e, w, t) e##w##t
#include <dl-r_debug.h>
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 struct r_debug. */
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"));
{
EW(Addr) off = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
off = E(r_debug_offset) (&dyn[j], memfd, off);
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;
}
}
if (r.r_map != 0)
{
list = r.r_map;
break;
}
}
}
free (dyn);
break;

15
elf/tst-dlmopen4.c
View File

@ -25,16 +25,9 @@
#include <support/check.h>
#include <support/test-driver.h>
#ifndef ELF_MACHINE_GET_R_DEBUG
# define ELF_MACHINE_GET_R_DEBUG(d) \
(__extension__ ({ \
struct r_debug_extended *debug; \
if ((d)->d_tag == DT_DEBUG) \
debug = (struct r_debug_extended *) (d)->d_un.d_ptr; \
else \
debug = NULL; \
debug; }))
#endif
#define E(x) x
#define EW(x) ElfW(x)
#include <dl-r_debug.h>
static int
do_test (void)
@ -44,7 +37,7 @@ do_test (void)
for (d = _DYNAMIC; d->d_tag != DT_NULL; ++d)
{
debug = ELF_MACHINE_GET_R_DEBUG (d);
debug = (struct r_debug_extended *) r_debug_address (d);
if (debug != NULL)
break;
}

36
sysdeps/generic/dl-r_debug.h Normal file
View File

@ -0,0 +1,36 @@
/* Function to access r_debug structure. Generic version.
Copyright (C) 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/>. */
/* Return the address of the struct r_debug after relocation. */
static inline EW(Addr)
E(r_debug_address) (EW(Dyn) *d)
{
if (d->d_tag == DT_DEBUG)
return (EW(Addr)) d->d_un.d_ptr;
return 0;
}
/* Return the offset of the struct r_debug before relocation. */
static inline EW(Addr)
E(r_debug_offset) (EW(Dyn) *d, int fd, EW(Addr) offset)
{
return E(r_debug_address) (d);
}

64
sysdeps/mips/dl-r_debug.h Normal file
View File

@ -0,0 +1,64 @@
/* Function to access r_debug structure. MIPS specific version.
Copyright (C) 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/>. */
#ifdef EW_
/* Return the offset of the struct r_debug before relocation. */
static inline EW(Addr)
E(r_debug_offset) (EW(Dyn) *d, int fd, EW(Addr) offset)
{
switch (d->d_tag)
{
case DT_MIPS_RLD_MAP_REL:
offset += d->d_un.d_val;
break;
case DT_MIPS_RLD_MAP:
offset = d->d_un.d_ptr;
break;
default:
return 0;
}
if (pread (fd, &offset, sizeof (offset), offset) != sizeof (offset))
return 0;
return offset;
}
#else
/* Return the address of the struct r_debug after relocation. */
static inline EW(Addr)
E(r_debug_address) (EW(Dyn) *d)
{
EW(Addr) ptr;
switch (d->d_tag)
{
case DT_MIPS_RLD_MAP_REL:
ptr = ((EW(Addr)) d) + d->d_un.d_val;
break;
case DT_MIPS_RLD_MAP:
ptr = d->d_un.d_ptr;
break;
default:
return 0;
}
return *(EW(Addr) *) ptr;
}
#endif