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/* Return build ID information for a module.
Copyright (C) 2007-2010 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/>. */
#include "libdwflP.h"
static int
found_build_id (Dwfl_Module *mod, bool set,
const void *bits, int len, GElf_Addr vaddr)
{
if (!set)
/* When checking bits, we do not compare VADDR because the
address found in a debuginfo file may not match the main
file as modified by prelink. */
return 1 + (mod->build_id_len == len
&& !memcmp (bits, mod->build_id_bits, len));
void *copy = malloc (len);
if (unlikely (copy == NULL))
{
__libdwfl_seterrno (DWFL_E_NOMEM);
return -1;
}
mod->build_id_bits = memcpy (copy, bits, len);
mod->build_id_vaddr = vaddr;
mod->build_id_len = len;
return len;
}
#define NO_VADDR ((GElf_Addr) -1l)
int
internal_function
__libdwfl_find_elf_build_id (Dwfl_Module *mod, Elf *elf,
const void **build_id_bits,
GElf_Addr *build_id_elfaddr, int *build_id_len)
{
GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem);
if (unlikely (ehdr == NULL))
{
__libdwfl_seterrno (DWFL_E_LIBELF);
return -1;
}
// MOD->E_TYPE is zero here.
assert (ehdr->e_type != ET_REL || mod != NULL);
int check_notes (Elf_Data *data, GElf_Addr data_elfaddr)
{
size_t pos = 0;
GElf_Nhdr nhdr;
size_t name_pos;
size_t desc_pos;
while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos, &desc_pos)) > 0)
if (nhdr.n_type == NT_GNU_BUILD_ID
&& nhdr.n_namesz == sizeof "GNU" && !memcmp (data->d_buf + name_pos,
"GNU", sizeof "GNU"))
{
*build_id_bits = data->d_buf + desc_pos;
*build_id_elfaddr = (data_elfaddr == NO_VADDR
? 0 : data_elfaddr + desc_pos);
*build_id_len = nhdr.n_descsz;
return 1;
}
return 0;
}
size_t shstrndx = SHN_UNDEF;
int result = 0;
Elf_Scn *scn = elf_nextscn (elf, NULL);
if (scn == NULL)
{
/* No sections, have to look for phdrs. */
size_t phnum;
if (unlikely (elf_getphdrnum (elf, &phnum) != 0))
{
__libdwfl_seterrno (DWFL_E_LIBELF);
return -1;
}
for (size_t i = 0; result == 0 && i < phnum; ++i)
{
GElf_Phdr phdr_mem;
GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
if (likely (phdr != NULL) && phdr->p_type == PT_NOTE)
result = check_notes (elf_getdata_rawchunk (elf,
phdr->p_offset,
phdr->p_filesz,
ELF_T_NHDR),
phdr->p_vaddr);
}
}
else
do
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE)
{
/* Determine the right sh_addr in this module. */
GElf_Addr vaddr = 0;
if (!(shdr->sh_flags & SHF_ALLOC))
vaddr = NO_VADDR;
else if (mod == NULL || ehdr->e_type != ET_REL)
vaddr = shdr->sh_addr;
else if (__libdwfl_relocate_value (mod, elf, &shstrndx,
elf_ndxscn (scn), &vaddr))
vaddr = NO_VADDR;
result = check_notes (elf_getdata (scn, NULL), vaddr);
}
}
while (result == 0 && (scn = elf_nextscn (elf, scn)) != NULL);
return result;
}
int
internal_function
__libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf)
{
const void *build_id_bits;
GElf_Addr build_id_elfaddr;
int build_id_len;
int result = __libdwfl_find_elf_build_id (mod, elf, &build_id_bits,
&build_id_elfaddr, &build_id_len);
if (result <= 0)
return result;
GElf_Addr build_id_vaddr = build_id_elfaddr + (build_id_elfaddr != 0
? mod->main_bias : 0);
return found_build_id (mod, set, build_id_bits, build_id_len, build_id_vaddr);
}
int
dwfl_module_build_id (Dwfl_Module *mod,
const unsigned char **bits, GElf_Addr *vaddr)
{
if (mod == NULL)
return -1;
if (mod->build_id_len == 0 && mod->main.elf != NULL)
{
/* We have the file, but have not examined it yet. */
int result = __libdwfl_find_build_id (mod, true, mod->main.elf);
if (result <= 0)
{
mod->build_id_len = -1; /* Cache negative result. */
return result;
}
}
if (mod->build_id_len <= 0)
return 0;
*bits = mod->build_id_bits;
*vaddr = mod->build_id_vaddr;
return mod->build_id_len;
}
INTDEF (dwfl_module_build_id)
NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138)
#ifdef SHARED
COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end)
int
_compat_vaddr_at_end_dwfl_module_build_id (Dwfl_Module *mod,
const unsigned char **bits,
GElf_Addr *vaddr)
{
int result = INTUSE(dwfl_module_build_id) (mod, bits, vaddr);
if (result > 0)
*vaddr += (result + 3) & -4;
return result;
}
#endif
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