You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
435 lines
10 KiB
435 lines
10 KiB
/* Recover relocatibility for addresses computed from debug information.
|
|
Copyright (C) 2005-2010, 2013, 2015 Red Hat, Inc.
|
|
This file is part of elfutils.
|
|
|
|
This file is free software; you can redistribute it and/or modify
|
|
it under the terms of either
|
|
|
|
* the GNU Lesser General Public License as published by the Free
|
|
Software Foundation; either version 3 of the License, or (at
|
|
your option) any later version
|
|
|
|
or
|
|
|
|
* the GNU General Public License as published by the Free
|
|
Software Foundation; either version 2 of the License, or (at
|
|
your option) any later version
|
|
|
|
or both in parallel, as here.
|
|
|
|
elfutils 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
|
|
General Public License for more details.
|
|
|
|
You should have received copies of the GNU General Public License and
|
|
the GNU Lesser General Public License along with this program. If
|
|
not, see <http://www.gnu.org/licenses/>. */
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
# include <config.h>
|
|
#endif
|
|
|
|
#include "libdwflP.h"
|
|
|
|
struct dwfl_relocation
|
|
{
|
|
size_t count;
|
|
struct
|
|
{
|
|
Elf_Scn *scn;
|
|
Elf_Scn *relocs;
|
|
const char *name;
|
|
GElf_Addr start, end;
|
|
} refs[0];
|
|
};
|
|
|
|
|
|
struct secref
|
|
{
|
|
struct secref *next;
|
|
Elf_Scn *scn;
|
|
Elf_Scn *relocs;
|
|
const char *name;
|
|
GElf_Addr start, end;
|
|
};
|
|
|
|
static int
|
|
compare_secrefs (const void *a, const void *b)
|
|
{
|
|
struct secref *const *p1 = a;
|
|
struct secref *const *p2 = b;
|
|
|
|
/* No signed difference calculation is correct here, since the
|
|
terms are unsigned and could be more than INT64_MAX apart. */
|
|
if ((*p1)->start < (*p2)->start)
|
|
return -1;
|
|
if ((*p1)->start > (*p2)->start)
|
|
return 1;
|
|
|
|
if ((*p1)->end < (*p2)->end)
|
|
return -1;
|
|
if ((*p1)->end > (*p2)->end)
|
|
return 1;
|
|
|
|
/* Same start/end, then just compare which section came first. */
|
|
return elf_ndxscn ((*p1)->scn) - elf_ndxscn ((*p2)->scn);
|
|
}
|
|
|
|
static int
|
|
cache_sections (Dwfl_Module *mod)
|
|
{
|
|
if (likely (mod->reloc_info != NULL))
|
|
return mod->reloc_info->count;
|
|
|
|
struct secref *refs = NULL;
|
|
size_t nrefs = 0;
|
|
|
|
size_t shstrndx;
|
|
if (unlikely (elf_getshdrstrndx (mod->main.elf, &shstrndx) < 0))
|
|
{
|
|
elf_error:
|
|
__libdwfl_seterrno (DWFL_E_LIBELF);
|
|
nrefs = -1;
|
|
goto free_refs;
|
|
}
|
|
|
|
bool check_reloc_sections = false;
|
|
Elf_Scn *scn = NULL;
|
|
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
|
|
{
|
|
GElf_Shdr shdr_mem;
|
|
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
|
|
if (shdr == NULL)
|
|
goto elf_error;
|
|
|
|
if ((shdr->sh_flags & SHF_ALLOC) && shdr->sh_addr == 0
|
|
&& mod->e_type == ET_REL)
|
|
{
|
|
/* This section might not yet have been looked at. */
|
|
if (__libdwfl_relocate_value (mod, mod->main.elf, &shstrndx,
|
|
elf_ndxscn (scn),
|
|
&shdr->sh_addr) != DWFL_E_NOERROR)
|
|
continue;
|
|
shdr = gelf_getshdr (scn, &shdr_mem);
|
|
if (unlikely (shdr == NULL))
|
|
goto elf_error;
|
|
}
|
|
|
|
if (shdr->sh_flags & SHF_ALLOC)
|
|
{
|
|
const char *name = elf_strptr (mod->main.elf, shstrndx,
|
|
shdr->sh_name);
|
|
if (unlikely (name == NULL))
|
|
goto elf_error;
|
|
|
|
struct secref *newref = malloc (sizeof *newref);
|
|
if (unlikely (newref == NULL))
|
|
{
|
|
nomem:
|
|
__libdwfl_seterrno (DWFL_E_NOMEM);
|
|
nrefs = -1;
|
|
goto free_refs;
|
|
}
|
|
|
|
newref->scn = scn;
|
|
newref->relocs = NULL;
|
|
newref->name = name;
|
|
newref->start = dwfl_adjusted_address (mod, shdr->sh_addr);
|
|
newref->end = newref->start + shdr->sh_size;
|
|
newref->next = refs;
|
|
refs = newref;
|
|
++nrefs;
|
|
}
|
|
|
|
if (mod->e_type == ET_REL
|
|
&& shdr->sh_size != 0
|
|
&& (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA)
|
|
&& mod->dwfl->callbacks->section_address != NULL)
|
|
{
|
|
if (shdr->sh_info < elf_ndxscn (scn))
|
|
{
|
|
/* We've already looked at the section these relocs apply to. */
|
|
Elf_Scn *tscn = elf_getscn (mod->main.elf, shdr->sh_info);
|
|
if (likely (tscn != NULL))
|
|
for (struct secref *sec = refs; sec != NULL; sec = sec->next)
|
|
if (sec->scn == tscn)
|
|
{
|
|
sec->relocs = scn;
|
|
break;
|
|
}
|
|
}
|
|
else
|
|
/* We'll have to do a second pass. */
|
|
check_reloc_sections = true;
|
|
}
|
|
}
|
|
|
|
mod->reloc_info = malloc (offsetof (struct dwfl_relocation, refs[nrefs]));
|
|
if (unlikely (mod->reloc_info == NULL))
|
|
goto nomem;
|
|
|
|
struct secref **sortrefs = malloc (nrefs * sizeof sortrefs[0]);
|
|
if (unlikely (sortrefs == NULL))
|
|
goto nomem;
|
|
|
|
for (size_t i = nrefs; i-- > 0; refs = refs->next)
|
|
sortrefs[i] = refs;
|
|
assert (refs == NULL);
|
|
|
|
qsort (sortrefs, nrefs, sizeof sortrefs[0], &compare_secrefs);
|
|
|
|
mod->reloc_info->count = nrefs;
|
|
for (size_t i = 0; i < nrefs; ++i)
|
|
{
|
|
mod->reloc_info->refs[i].name = sortrefs[i]->name;
|
|
mod->reloc_info->refs[i].scn = sortrefs[i]->scn;
|
|
mod->reloc_info->refs[i].relocs = sortrefs[i]->relocs;
|
|
mod->reloc_info->refs[i].start = sortrefs[i]->start;
|
|
mod->reloc_info->refs[i].end = sortrefs[i]->end;
|
|
free (sortrefs[i]);
|
|
}
|
|
|
|
free (sortrefs);
|
|
|
|
if (unlikely (check_reloc_sections))
|
|
{
|
|
/* There was a reloc section that preceded its target section.
|
|
So we have to scan again now that we have cached all the
|
|
possible target sections we care about. */
|
|
|
|
scn = NULL;
|
|
while ((scn = elf_nextscn (mod->main.elf, scn)) != NULL)
|
|
{
|
|
GElf_Shdr shdr_mem;
|
|
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
|
|
if (shdr == NULL)
|
|
goto elf_error;
|
|
|
|
if (shdr->sh_size != 0
|
|
&& (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA))
|
|
{
|
|
Elf_Scn *tscn = elf_getscn (mod->main.elf, shdr->sh_info);
|
|
if (likely (tscn != NULL))
|
|
for (size_t i = 0; i < nrefs; ++i)
|
|
if (mod->reloc_info->refs[i].scn == tscn)
|
|
{
|
|
mod->reloc_info->refs[i].relocs = scn;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
free_refs:
|
|
while (refs != NULL)
|
|
{
|
|
struct secref *ref = refs;
|
|
refs = ref->next;
|
|
free (ref);
|
|
}
|
|
|
|
return nrefs;
|
|
}
|
|
|
|
|
|
int
|
|
dwfl_module_relocations (Dwfl_Module *mod)
|
|
{
|
|
if (mod == NULL)
|
|
return -1;
|
|
|
|
switch (mod->e_type)
|
|
{
|
|
case ET_REL:
|
|
return cache_sections (mod);
|
|
|
|
case ET_DYN:
|
|
return 1;
|
|
|
|
case ET_EXEC:
|
|
assert (mod->main.vaddr == mod->low_addr);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
const char *
|
|
dwfl_module_relocation_info (Dwfl_Module *mod, unsigned int idx,
|
|
Elf32_Word *shndxp)
|
|
{
|
|
if (mod == NULL)
|
|
return NULL;
|
|
|
|
switch (mod->e_type)
|
|
{
|
|
case ET_REL:
|
|
break;
|
|
|
|
case ET_DYN:
|
|
if (idx != 0)
|
|
return NULL;
|
|
if (shndxp)
|
|
*shndxp = SHN_ABS;
|
|
return "";
|
|
|
|
default:
|
|
return NULL;
|
|
}
|
|
|
|
if (cache_sections (mod) < 0)
|
|
return NULL;
|
|
|
|
struct dwfl_relocation *sections = mod->reloc_info;
|
|
|
|
if (idx >= sections->count)
|
|
return NULL;
|
|
|
|
if (shndxp)
|
|
*shndxp = elf_ndxscn (sections->refs[idx].scn);
|
|
|
|
return sections->refs[idx].name;
|
|
}
|
|
|
|
/* Check that MOD is valid and make sure its relocation has been done. */
|
|
static bool
|
|
check_module (Dwfl_Module *mod)
|
|
{
|
|
if (mod == NULL)
|
|
return true;
|
|
|
|
if (INTUSE(dwfl_module_getsymtab) (mod) < 0)
|
|
{
|
|
Dwfl_Error error = dwfl_errno ();
|
|
if (error != DWFL_E_NO_SYMTAB)
|
|
{
|
|
__libdwfl_seterrno (error);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
if (mod->dw == NULL)
|
|
{
|
|
Dwarf_Addr bias;
|
|
if (INTUSE(dwfl_module_getdwarf) (mod, &bias) == NULL)
|
|
{
|
|
Dwfl_Error error = dwfl_errno ();
|
|
if (error != DWFL_E_NO_DWARF)
|
|
{
|
|
__libdwfl_seterrno (error);
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Find the index in MOD->reloc_info.refs containing *ADDR. */
|
|
static int
|
|
find_section (Dwfl_Module *mod, Dwarf_Addr *addr)
|
|
{
|
|
if (cache_sections (mod) < 0)
|
|
return -1;
|
|
|
|
struct dwfl_relocation *sections = mod->reloc_info;
|
|
|
|
/* The sections are sorted by address, so we can use binary search. */
|
|
size_t l = 0, u = sections->count;
|
|
while (l < u)
|
|
{
|
|
size_t idx = (l + u) / 2;
|
|
if (*addr < sections->refs[idx].start)
|
|
u = idx;
|
|
else if (*addr > sections->refs[idx].end)
|
|
l = idx + 1;
|
|
else
|
|
{
|
|
/* Consider the limit of a section to be inside it, unless it's
|
|
inside the next one. A section limit address can appear in
|
|
line records. */
|
|
if (*addr == sections->refs[idx].end
|
|
&& idx + 1 < sections->count
|
|
&& *addr == sections->refs[idx + 1].start)
|
|
++idx;
|
|
|
|
*addr -= sections->refs[idx].start;
|
|
return idx;
|
|
}
|
|
}
|
|
|
|
__libdwfl_seterrno (DWFL_E (LIBDW, DWARF_E_NO_MATCH));
|
|
return -1;
|
|
}
|
|
|
|
size_t
|
|
internal_function
|
|
__libdwfl_find_section_ndx (Dwfl_Module *mod, Dwarf_Addr *addr)
|
|
{
|
|
int idx = find_section (mod, addr);
|
|
if (unlikely (idx == -1))
|
|
return SHN_UNDEF;
|
|
|
|
return elf_ndxscn (mod->reloc_info->refs[idx].scn);
|
|
}
|
|
|
|
int
|
|
dwfl_module_relocate_address (Dwfl_Module *mod, Dwarf_Addr *addr)
|
|
{
|
|
if (unlikely (check_module (mod)))
|
|
return -1;
|
|
|
|
switch (mod->e_type)
|
|
{
|
|
case ET_REL:
|
|
return find_section (mod, addr);
|
|
|
|
case ET_DYN:
|
|
/* All relative to first and only relocation base: module start. */
|
|
*addr -= mod->low_addr;
|
|
break;
|
|
|
|
default:
|
|
/* Already absolute, dwfl_module_relocations returned zero. We
|
|
shouldn't really have been called, but it's a harmless no-op. */
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
INTDEF (dwfl_module_relocate_address)
|
|
|
|
Elf_Scn *
|
|
dwfl_module_address_section (Dwfl_Module *mod, Dwarf_Addr *address,
|
|
Dwarf_Addr *bias)
|
|
{
|
|
if (check_module (mod))
|
|
return NULL;
|
|
|
|
int idx = find_section (mod, address);
|
|
if (idx < 0)
|
|
return NULL;
|
|
|
|
if (mod->reloc_info->refs[idx].relocs != NULL)
|
|
{
|
|
assert (mod->e_type == ET_REL);
|
|
|
|
Elf_Scn *tscn = mod->reloc_info->refs[idx].scn;
|
|
Elf_Scn *relocscn = mod->reloc_info->refs[idx].relocs;
|
|
Dwfl_Error result = __libdwfl_relocate_section (mod, mod->main.elf,
|
|
relocscn, tscn, true);
|
|
if (likely (result == DWFL_E_NOERROR))
|
|
mod->reloc_info->refs[idx].relocs = NULL;
|
|
else
|
|
{
|
|
__libdwfl_seterrno (result);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
*bias = dwfl_adjusted_address (mod, 0);
|
|
return mod->reloc_info->refs[idx].scn;
|
|
}
|
|
INTDEF (dwfl_module_address_section)
|