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;
}
Dwarf_CFI *
dwfl_module_eh_cfi (Dwfl_Module *mod, Dwarf_Addr *bias)
{
if (mod == NULL)
return NULL;
if (mod->eh_cfi != NULL)
{
*bias = dwfl_adjusted_address (mod, 0);
return mod->eh_cfi;
}
__libdwfl_getelf (mod);
if (mod->elferr != DWFL_E_NOERROR)
{
__libdwfl_seterrno (mod->elferr);
return NULL;
}
*bias = dwfl_adjusted_address (mod, 0);
return __libdwfl_set_cfi (mod, &mod->eh_cfi,
INTUSE(dwarf_getcfi_elf) (mod->main.elf));
}
Dwfl_Error
internal_function
__libdwfl_relocate_value (Dwfl_Module *mod, Elf *elf, size_t *shstrndx,
Elf32_Word shndx, GElf_Addr *value)
{
assert (mod->e_type == ET_REL);
Elf_Scn *refscn = elf_getscn (elf, shndx);
GElf_Shdr refshdr_mem, *refshdr = gelf_getshdr (refscn, &refshdr_mem);
if (refshdr == NULL)
return DWFL_E_LIBELF;
if (refshdr->sh_addr == 0 && (refshdr->sh_flags & SHF_ALLOC))
{
/* This is a loaded section. Find its actual
address and update the section header. */
if (*shstrndx == SHN_UNDEF
&& unlikely (elf_getshdrstrndx (elf, shstrndx) < 0))
return DWFL_E_LIBELF;
const char *name = elf_strptr (elf, *shstrndx, refshdr->sh_name);
if (unlikely (name == NULL))
return DWFL_E_LIBELF;
if ((*mod->dwfl->callbacks->section_address) (MODCB_ARGS (mod),
name, shndx, refshdr,
&refshdr->sh_addr))
return CBFAIL;
if (refshdr->sh_addr == (Dwarf_Addr) -1l)
/* The callback indicated this section wasn't really loaded but we
don't really care. */
refshdr->sh_addr = 0; /* Make no adjustment below. */
/* Update the in-core file's section header to show the final
load address (or unloadedness). This serves as a cache,
so we won't get here again for the same section. */
if (likely (refshdr->sh_addr != 0)
&& unlikely (! gelf_update_shdr (refscn, refshdr)))
return DWFL_E_LIBELF;
}
if (refshdr->sh_flags & SHF_ALLOC)
/* Apply the adjustment. */
*value += dwfl_adjusted_address (mod, refshdr->sh_addr);
return DWFL_E_NOERROR;
}
Elf *
dwfl_module_getelf (Dwfl_Module *mod, GElf_Addr *loadbase)
{
if (mod == NULL)
return NULL;
__libdwfl_getelf (mod);
if (mod->elferr == DWFL_E_NOERROR)
{
if (mod->e_type == ET_REL && ! mod->main.relocated)
{
/* Before letting them get at the Elf handle,
apply all the relocations we know how to. */
mod->main.relocated = true;
if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
{
(void) __libdwfl_relocate (mod, mod->main.elf, false);
if (mod->debug.elf == mod->main.elf)
mod->debug.relocated = true;
else if (mod->debug.elf != NULL && ! mod->debug.relocated)
{
mod->debug.relocated = true;
(void) __libdwfl_relocate (mod, mod->debug.elf, false);
}
}
}
*loadbase = dwfl_adjusted_address (mod, 0);
return mod->main.elf;
}
__libdwfl_seterrno (mod->elferr);
return NULL;
}
static int
cache_sections (Dwfl_Module *mod)
{
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);
return -1;
}
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 = alloca (sizeof *newref);
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 (mod->reloc_info == NULL)
{
__libdwfl_seterrno (DWFL_E_NOMEM);
return -1;
}
struct secref **sortrefs = alloca (nrefs * sizeof sortrefs[0]);
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;
}
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;
}
}
}
}
return nrefs;
}
