map_s *elf_set_breakpoints(proc_s *proc)
{
elf_info_s *elf = elf_symbols(proc->fd);
map_s *brkp = map_init(32, cmp_addr);
for (size_t i = 0; i < elf->replt_count; ++i) {
void *ret;
GElf_Rel rel;
GElf_Rela rela;
const char *name;
GElf_Sym sym;
GElf_Addr addr;
/* local relocation entries */
if (elf->replt->d_type == ELF_T_REL) {
ret = gelf_getrel(elf->replt, i, &rel);
rela.r_offset = rel.r_offset;
rela.r_info = rel.r_info;
rela.r_addend = 0;
}
/* external relocation entries */
else
ret = gelf_getrela(elf->replt, i, &rela);
gelf_getsym(elf->dynsym, ELF64_R_SYM(rela.r_info), &sym);
name = elf->dynstr + sym.st_name;
addr = elf->plt_addr + (i + 1) * 16;
breakpoint_create(brkp, addr, name, proc->pid);
}
return brkp;
}
static void
_dwarf_elf_apply_reloc(Dwarf_Debug dbg, void *buf, Elf_Data *rel_data,
Elf_Data *symtab_data, int endian)
{
Dwarf_Unsigned type;
GElf_Rela rela;
GElf_Sym sym;
size_t symndx;
uint64_t offset;
int size, j;
j = 0;
while (gelf_getrela(rel_data, j++, &rela) != NULL) {
symndx = GELF_R_SYM(rela.r_info);
type = GELF_R_TYPE(rela.r_info);
if (gelf_getsym(symtab_data, symndx, &sym) == NULL)
continue;
offset = rela.r_offset;
size = _dwarf_get_reloc_size(dbg, type);
if (endian == ELFDATA2MSB)
_dwarf_write_msb(buf, &offset, rela.r_addend, size);
else
_dwarf_write_lsb(buf, &offset, rela.r_addend, size);
}
}
static void
_dwarf_elf_apply_rela_reloc(Dwarf_Debug dbg, void *buf, Elf_Data *rel_data,
Elf_Data *symtab_data, int endian)
{
GElf_Rela rela;
int j;
j = 0;
while (gelf_getrela(rel_data, j++, &rela) != NULL)
_dwarf_elf_write_reloc(dbg, symtab_data, endian, buf,
rela.r_offset, rela.r_info, rela.r_addend, 0);
}
static GHashTable* parse_plt(Elf *e, const char *filename)
{
GElf_Shdr shdr;
Elf_Data *plt_data;
uintptr_t plt_base;
size_t plt_section_index = xelf_section_by_name(e, ".plt", filename, &plt_data, &shdr);
if (plt_section_index == 0)
{
VERB1 log("No .plt section found for %s", filename);
return NULL;
}
plt_base = shdr.sh_addr;
/* Find the relocation section for .plt (typically .rela.plt), together
* with its symbol and string table
*/
Elf_Data *rela_plt_data = NULL;
Elf_Data *plt_symbols = NULL;
size_t stringtable = 0;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL)
{
if (gelf_getshdr(scn, &shdr) != &shdr)
{
VERB1 log_elf_error("gelf_getshdr", filename);
continue;
}
if (shdr.sh_type == SHT_RELA && shdr.sh_info == plt_section_index)
{
rela_plt_data = elf_getdata(scn, NULL);
if (rela_plt_data == NULL)
{
VERB1 log_elf_error("elf_getdata", filename);
break;
}
/* Get symbol section for .rela.plt */
Elf_Scn *symscn = elf_getscn(e, shdr.sh_link);
if (symscn == NULL)
{
VERB1 log_elf_error("elf_getscn", filename);
break;
}
plt_symbols = elf_getdata(symscn, NULL);
if (plt_symbols == NULL)
{
VERB1 log_elf_error("elf_getdata", filename);
break;
}
/* Get string table for the symbol table. */
if (gelf_getshdr(symscn, &shdr) != &shdr)
{
VERB1 log_elf_error("gelf_getshdr", filename);
break;
}
stringtable = shdr.sh_link;
break;
}
}
if (stringtable == 0)
{
VERB1 log("Unable to read symbol table for .plt for file %s", filename);
return NULL;
}
/* Init hash table
* keys are pointers to integers which we allocate with malloc
* values are owned by libelf, so we don't need to free them */
GHashTable *hash = g_hash_table_new_full(g_int64_hash, g_int64_equal, free, NULL);
/* PLT looks like this (see also AMD64 ABI, page 78):
*
* Disassembly of section .plt:
*
* 0000003463e01010 <attr_removef@plt-0x10>:
* 3463e01010: ff 35 2a 2c 20 00 pushq 0x202c2a(%rip) <-- here is plt_base
* 3463e01016: ff 25 2c 2c 20 00 jmpq *0x202c2c(%rip) each "slot" is 16B wide
* 3463e0101c: 0f 1f 40 00 nopl 0x0(%rax) 0-th slot is skipped
*
* 0000003463e01020 <attr_removef@plt>:
* 3463e01020: ff 25 2a 2c 20 00 jmpq *0x202c2a(%rip)
* 3463e01026: 68 00 00 00 00 pushq $0x0 <-- this is the number we want
* 3463e0102b: e9 e0 ff ff ff jmpq 3463e01010 <_init+0x18>
*
* 0000003463e01030 <fgetxattr@plt>:
* 3463e01030: ff 25 22 2c 20 00 jmpq *0x202c22(%rip)
* 3463e01036: 68 01 00 00 00 pushq $0x1
* 3463e0103b: e9 d0 ff ff ff jmpq 3463e01010 <_init+0x18>
*/
unsigned plt_offset;
uint32_t *plt_index;
GElf_Rela rela;
GElf_Sym symb;
for (plt_offset = 16; plt_offset < plt_data->d_size; plt_offset += 16)
{
plt_index = (uint32_t*)(plt_data->d_buf + plt_offset + 7);
if(gelf_getrela(rela_plt_data, *plt_index, &rela) != &rela)
{
VERB1 log_elf_error("gelf_getrela", filename);
continue;
}
if(gelf_getsym(plt_symbols, GELF_R_SYM(rela.r_info), &symb) != &symb)
{
VERB1 log_elf_error("gelf_getsym", filename);
continue;
}
char *symbol = elf_strptr(e, stringtable, symb.st_name);
uintptr_t *addr = addr_alloc((uintptr_t)(plt_base + plt_offset));
VERB3 log("[%02x] %jx: %s", *plt_index, (uintptr_t)(*addr), symbol);
g_hash_table_insert(hash, addr, symbol);
}
return hash;
}
static gboolean
handle_dwarf2_section (DebuginfoData *data, GHashTable *files, GError **error)
{
Elf_Data *e_data;
int i;
debug_section_t *debug_sections;
ptr_size = 0;
if (data->ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
{
do_read_16 = buf_read_ule16;
do_read_32 = buf_read_ule32;
}
else if (data->ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
{
do_read_16 = buf_read_ube16;
do_read_32 = buf_read_ube32;
}
else
{
return flatpak_fail (error, "%s: Wrong ELF data encoding", data->filename);
}
debug_sections = data->debug_sections;
if (debug_sections[DEBUG_INFO].data != NULL)
{
unsigned char *ptr, *endcu, *endsec;
uint32_t value;
struct abbrev_tag *t;
g_autofree REL *relbuf = NULL;
if (debug_sections[DEBUG_INFO].relsec)
{
Elf_Scn *scn;
int ndx, maxndx;
GElf_Rel rel;
GElf_Rela rela;
GElf_Sym sym;
GElf_Addr base = data->shdr[debug_sections[DEBUG_INFO].sec].sh_addr;
Elf_Data *symdata = NULL;
int rtype;
i = debug_sections[DEBUG_INFO].relsec;
scn = data->scns[i];
e_data = elf_getdata (scn, NULL);
g_assert (e_data != NULL && e_data->d_buf != NULL);
g_assert (elf_getdata (scn, e_data) == NULL);
g_assert (e_data->d_off == 0);
g_assert (e_data->d_size == data->shdr[i].sh_size);
maxndx = data->shdr[i].sh_size / data->shdr[i].sh_entsize;
relbuf = g_malloc (maxndx * sizeof (REL));
reltype = data->shdr[i].sh_type;
symdata = elf_getdata (data->scns[data->shdr[i].sh_link], NULL);
g_assert (symdata != NULL && symdata->d_buf != NULL);
g_assert (elf_getdata (data->scns[data->shdr[i].sh_link], symdata) == NULL);
g_assert (symdata->d_off == 0);
g_assert (symdata->d_size == data->shdr[data->shdr[i].sh_link].sh_size);
for (ndx = 0, relend = relbuf; ndx < maxndx; ++ndx)
{
if (data->shdr[i].sh_type == SHT_REL)
{
gelf_getrel (e_data, ndx, &rel);
rela.r_offset = rel.r_offset;
rela.r_info = rel.r_info;
rela.r_addend = 0;
}
else
{
gelf_getrela (e_data, ndx, &rela);
}
gelf_getsym (symdata, ELF64_R_SYM (rela.r_info), &sym);
/* Relocations against section symbols are uninteresting
in REL. */
if (data->shdr[i].sh_type == SHT_REL && sym.st_value == 0)
continue;
/* Only consider relocations against .debug_str, .debug_line
and .debug_abbrev. */
if (sym.st_shndx != debug_sections[DEBUG_STR].sec &&
sym.st_shndx != debug_sections[DEBUG_LINE].sec &&
sym.st_shndx != debug_sections[DEBUG_ABBREV].sec)
continue;
rela.r_addend += sym.st_value;
rtype = ELF64_R_TYPE (rela.r_info);
switch (data->ehdr.e_machine)
{
case EM_SPARC:
case EM_SPARC32PLUS:
case EM_SPARCV9:
if (rtype != R_SPARC_32 && rtype != R_SPARC_UA32)
goto fail;
break;
case EM_386:
if (rtype != R_386_32)
goto fail;
break;
case EM_PPC:
case EM_PPC64:
if (rtype != R_PPC_ADDR32 && rtype != R_PPC_UADDR32)
goto fail;
break;
case EM_S390:
if (rtype != R_390_32)
goto fail;
break;
case EM_IA_64:
if (rtype != R_IA64_SECREL32LSB)
goto fail;
break;
case EM_X86_64:
if (rtype != R_X86_64_32)
goto fail;
break;
case EM_ALPHA:
if (rtype != R_ALPHA_REFLONG)
goto fail;
break;
#if defined(EM_AARCH64) && defined(R_AARCH64_ABS32)
case EM_AARCH64:
if (rtype != R_AARCH64_ABS32)
goto fail;
break;
#endif
case EM_68K:
if (rtype != R_68K_32)
goto fail;
break;
default:
fail:
return flatpak_fail (error, "%s: Unhandled relocation %d in .debug_info section",
data->filename, rtype);
}
relend->ptr = debug_sections[DEBUG_INFO].data
+ (rela.r_offset - base);
relend->addend = rela.r_addend;
++relend;
}
if (relbuf == relend)
{
g_free (relbuf);
relbuf = NULL;
relend = NULL;
}
else
{
qsort (relbuf, relend - relbuf, sizeof (REL), rel_cmp);
}
}
ptr = debug_sections[DEBUG_INFO].data;
relptr = relbuf;
endsec = ptr + debug_sections[DEBUG_INFO].size;
while (ptr != NULL && ptr < endsec)
{
g_autoptr(GHashTable) abbrev = NULL;
if (ptr + 11 > endsec)
return flatpak_fail (error, "%s: .debug_info CU header too small", data->filename);
endcu = ptr + 4;
endcu += read_32 (ptr);
if (endcu == ptr + 0xffffffff)
return flatpak_fail (error, "%s: 64-bit DWARF not supported", data->filename);
if (endcu > endsec)
return flatpak_fail (error, "%s: .debug_info too small", data->filename);
cu_version = read_16 (ptr);
if (cu_version != 2 && cu_version != 3 && cu_version != 4)
return flatpak_fail (error, "%s: DWARF version %d unhandled", data->filename, cu_version);
value = read_32_relocated (ptr);
if (value >= debug_sections[DEBUG_ABBREV].size)
{
if (debug_sections[DEBUG_ABBREV].data == NULL)
return flatpak_fail (error, "%s: .debug_abbrev not present", data->filename);
else
return flatpak_fail (error, "%s: DWARF CU abbrev offset too large", data->filename);
}
if (ptr_size == 0)
{
ptr_size = read_1 (ptr);
if (ptr_size != 4 && ptr_size != 8)
return flatpak_fail (error, "%s: Invalid DWARF pointer size %d", data->filename, ptr_size);
}
else if (read_1 (ptr) != ptr_size)
{
return flatpak_fail (error, "%s: DWARF pointer size differs between CUs", data->filename);
}
abbrev = read_abbrev (data,
debug_sections[DEBUG_ABBREV].data + value);
while (ptr < endcu)
{
guint entry = read_uleb128 (ptr);
if (entry == 0)
continue;
t = g_hash_table_lookup (abbrev, GINT_TO_POINTER (entry));
if (t == NULL)
{
g_warning ("%s: Could not find DWARF abbreviation %d", data->filename, entry);
}
else
{
ptr = handle_attributes (data, ptr, t, files, error);
if (ptr == NULL)
return FALSE;
}
}
}
}
return TRUE;
}
struct sr_elf_plt_entry *
sr_elf_get_procedure_linkage_table(const char *filename,
char **error_message)
{
#ifdef WITH_ELFUTILS
/* Open the input file. */
int fd = open(filename, O_RDONLY);
if (fd < 0)
{
*error_message = sr_asprintf("Failed to open file %s: %s",
filename,
strerror(errno));
return NULL;
}
/* Initialize libelf on the opened file. */
Elf *elf = elf_begin(fd, ELF_C_READ, NULL);
if (!elf)
{
*error_message = sr_asprintf("Failed to run elf_begin on file %s: %s",
filename,
elf_errmsg(-1));
close(fd);
return NULL;
}
/* Find the .plt section. */
GElf_Shdr shdr;
Elf_Data *plt_data;
char *find_section_error_message;
size_t plt_section_index = find_elf_section_by_name(elf,
".plt",
&plt_data,
&shdr,
&find_section_error_message);
if (0 == plt_section_index)
{
*error_message = sr_asprintf("Failed to find .plt section for %s: %s",
filename,
find_section_error_message);
free(find_section_error_message);
elf_end(elf);
close(fd);
return NULL;
}
/* Find the relocation section for .plt (typically .rela.plt), together
* with its symbol and string table
*/
uint64_t plt_base = shdr.sh_addr;
Elf_Data *rela_plt_data = NULL;
Elf_Data *plt_symbols = NULL;
size_t stringtable = 0;
Elf_Scn *section = NULL;
while ((section = elf_nextscn(elf, section)) != NULL)
{
if (gelf_getshdr(section, &shdr) != &shdr)
{
*error_message = sr_asprintf("gelf_getshdr failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
if (shdr.sh_type == SHT_RELA &&
shdr.sh_info == plt_section_index)
{
rela_plt_data = elf_getdata(section, NULL);
if (!rela_plt_data)
{
*error_message = sr_asprintf("elf_getdata failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
/* Get symbol section for .rela.plt */
Elf_Scn *symbol_section = elf_getscn(elf, shdr.sh_link);
if (!symbol_section)
{
*error_message = sr_asprintf("elf_getscn failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
plt_symbols = elf_getdata(symbol_section, NULL);
if (!plt_symbols)
{
*error_message = sr_asprintf("elf_getdata failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
/* Get string table for the symbol table. */
if (gelf_getshdr(symbol_section, &shdr) != &shdr)
{
*error_message = sr_asprintf("gelf_getshdr failed for %s: %s",
filename,
elf_errmsg(-1));
elf_end(elf);
close(fd);
return NULL;
}
stringtable = shdr.sh_link;
break;
}
}
if (0 == stringtable)
{
*error_message = sr_asprintf("Unable to read symbol table for .plt for file %s",
filename);
elf_end(elf);
close(fd);
return NULL;
}
/* PLT looks like this (see also AMD64 ABI, page 78):
*
* Disassembly of section .plt:
*
* 0000003463e01010 <attr_removef@plt-0x10>:
* 3463e01010: ff 35 2a 2c 20 00 pushq 0x202c2a(%rip) <-- here is plt_base
* 3463e01016: ff 25 2c 2c 20 00 jmpq *0x202c2c(%rip) each "slot" is 16B wide
* 3463e0101c: 0f 1f 40 00 nopl 0x0(%rax) 0-th slot is skipped
*
* 0000003463e01020 <attr_removef@plt>:
* 3463e01020: ff 25 2a 2c 20 00 jmpq *0x202c2a(%rip)
* 3463e01026: 68 00 00 00 00 pushq $0x0 <-- this is the number we want
* 3463e0102b: e9 e0 ff ff ff jmpq 3463e01010 <_init+0x18>
*
* 0000003463e01030 <fgetxattr@plt>:
* 3463e01030: ff 25 22 2c 20 00 jmpq *0x202c22(%rip)
* 3463e01036: 68 01 00 00 00 pushq $0x1
* 3463e0103b: e9 d0 ff ff ff jmpq 3463e01010 <_init+0x18>
*/
struct sr_elf_plt_entry *result = NULL, *last = NULL;
for (unsigned plt_offset = 16; plt_offset < plt_data->d_size; plt_offset += 16)
{
uint32_t *plt_index = (uint32_t*)(plt_data->d_buf + plt_offset + 7);
GElf_Rela rela;
if (gelf_getrela(rela_plt_data, *plt_index, &rela) != &rela)
{
*error_message = sr_asprintf("gelf_getrela failed for %s: %s",
filename,
elf_errmsg(-1));
sr_elf_procedure_linkage_table_free(result);
elf_end(elf);
close(fd);
return NULL;
}
GElf_Sym symb;
if (gelf_getsym(plt_symbols, GELF_R_SYM(rela.r_info), &symb) != &symb)
{
*error_message = sr_asprintf("gelf_getsym failed for %s: %s",
filename,
elf_errmsg(-1));
sr_elf_procedure_linkage_table_free(result);
elf_end(elf);
close(fd);
return NULL;
}
struct sr_elf_plt_entry *entry = sr_malloc(sizeof(struct sr_elf_plt_entry));
entry->symbol_name = sr_strdup(elf_strptr(elf, stringtable,
symb.st_name));
entry->address = (uint64_t)(plt_base + plt_offset);
entry->next = NULL;
if (result)
{
last->next = entry;
last = entry;
}
else
result = last = entry;
}
elf_end(elf);
close(fd);
return result;
#else /* WITH_ELFUTILS */
*error_message = sr_asprintf("satyr compiled without elfutils");
return NULL;
#endif /* WITH_ELFUTILS */
}
static Dwfl_Error
relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr,
size_t shstrndx, struct reloc_symtab_cache *reloc_symtab,
Elf_Scn *scn, GElf_Shdr *shdr,
Elf_Scn *tscn, bool debugscn, bool partial)
{
/* First, fetch the name of the section these relocations apply to. */
GElf_Shdr tshdr_mem;
GElf_Shdr *tshdr = gelf_getshdr (tscn, &tshdr_mem);
const char *tname = elf_strptr (relocated, shstrndx, tshdr->sh_name);
if (tname == NULL)
return DWFL_E_LIBELF;
if (unlikely (tshdr->sh_type == SHT_NOBITS) || unlikely (tshdr->sh_size == 0))
/* No contents to relocate. */
return DWFL_E_NOERROR;
if (debugscn && ! ebl_debugscn_p (mod->ebl, tname))
/* This relocation section is not for a debugging section.
Nothing to do here. */
return DWFL_E_NOERROR;
/* Fetch the section data that needs the relocations applied. */
Elf_Data *tdata = elf_rawdata (tscn, NULL);
if (tdata == NULL)
return DWFL_E_LIBELF;
/* Apply one relocation. Returns true for any invalid data. */
Dwfl_Error relocate (GElf_Addr offset, const GElf_Sxword *addend,
int rtype, int symndx)
{
/* First see if this is a reloc we can handle.
If we are skipping it, don't bother resolving the symbol. */
if (unlikely (rtype == 0))
/* In some odd situations, the linker can leave R_*_NONE relocs
behind. This is probably bogus ld -r behavior, but the only
cases it's known to appear in are harmless: DWARF data
referring to addresses in a section that has been discarded.
So we just pretend it's OK without further relocation. */
return DWFL_E_NOERROR;
Elf_Type type = ebl_reloc_simple_type (mod->ebl, rtype);
if (unlikely (type == ELF_T_NUM))
return DWFL_E_BADRELTYPE;
/* First, resolve the symbol to an absolute value. */
GElf_Addr value;
if (symndx == STN_UNDEF)
/* When strip removes a section symbol referring to a
section moved into the debuginfo file, it replaces
that symbol index in relocs with STN_UNDEF. We
don't actually need the symbol, because those relocs
are always references relative to the nonallocated
debugging sections, which start at zero. */
value = 0;
else
{
GElf_Sym sym;
GElf_Word shndx;
Dwfl_Error error = relocate_getsym (mod, relocated, reloc_symtab,
symndx, &sym, &shndx);
if (unlikely (error != DWFL_E_NOERROR))
return error;
if (shndx == SHN_UNDEF || shndx == SHN_COMMON)
{
/* Maybe we can figure it out anyway. */
error = resolve_symbol (mod, reloc_symtab, &sym, shndx);
if (error != DWFL_E_NOERROR
&& !(error == DWFL_E_RELUNDEF && shndx == SHN_COMMON))
return error;
}
value = sym.st_value;
}
/* These are the types we can relocate. */
#define TYPES DO_TYPE (BYTE, Byte); DO_TYPE (HALF, Half); \
DO_TYPE (WORD, Word); DO_TYPE (SWORD, Sword); \
DO_TYPE (XWORD, Xword); DO_TYPE (SXWORD, Sxword)
size_t size;
switch (type)
{
#define DO_TYPE(NAME, Name) \
case ELF_T_##NAME: \
size = sizeof (GElf_##Name); \
break
TYPES;
#undef DO_TYPE
default:
return DWFL_E_BADRELTYPE;
}
if (offset + size > tdata->d_size)
return DWFL_E_BADRELOFF;
#define DO_TYPE(NAME, Name) GElf_##Name Name;
union { TYPES; } tmpbuf;
#undef DO_TYPE
Elf_Data tmpdata =
{
.d_type = type,
.d_buf = &tmpbuf,
.d_size = size,
.d_version = EV_CURRENT,
};
Elf_Data rdata =
{
.d_type = type,
.d_buf = tdata->d_buf + offset,
.d_size = size,
.d_version = EV_CURRENT,
};
/* XXX check for overflow? */
if (addend)
{
/* For the addend form, we have the value already. */
value += *addend;
switch (type)
{
#define DO_TYPE(NAME, Name) \
case ELF_T_##NAME: \
tmpbuf.Name = value; \
break
TYPES;
#undef DO_TYPE
default:
abort ();
}
}
else
{
/* Extract the original value and apply the reloc. */
Elf_Data *d = gelf_xlatetom (relocated, &tmpdata, &rdata,
ehdr->e_ident[EI_DATA]);
if (d == NULL)
return DWFL_E_LIBELF;
assert (d == &tmpdata);
switch (type)
{
#define DO_TYPE(NAME, Name) \
case ELF_T_##NAME: \
tmpbuf.Name += (GElf_##Name) value; \
break
TYPES;
#undef DO_TYPE
default:
abort ();
}
}
/* Now convert the relocated datum back to the target
format. This will write into rdata.d_buf, which
points into the raw section data being relocated. */
Elf_Data *s = gelf_xlatetof (relocated, &rdata, &tmpdata,
ehdr->e_ident[EI_DATA]);
if (s == NULL)
return DWFL_E_LIBELF;
assert (s == &rdata);
/* We have applied this relocation! */
return DWFL_E_NOERROR;
}
/* Fetch the relocation section and apply each reloc in it. */
Elf_Data *reldata = elf_getdata (scn, NULL);
if (reldata == NULL)
return DWFL_E_LIBELF;
Dwfl_Error result = DWFL_E_NOERROR;
bool first_badreltype = true;
inline void check_badreltype (void)
{
if (first_badreltype)
{
first_badreltype = false;
if (ebl_get_elfmachine (mod->ebl) == EM_NONE)
/* This might be because ebl_openbackend failed to find
any libebl_CPU.so library. Diagnose that clearly. */
result = DWFL_E_UNKNOWN_MACHINE;
}
}
size_t nrels = shdr->sh_size / shdr->sh_entsize;
size_t complete = 0;
if (shdr->sh_type == SHT_REL)
for (size_t relidx = 0; !result && relidx < nrels; ++relidx)
{
GElf_Rel rel_mem, *r = gelf_getrel (reldata, relidx, &rel_mem);
if (r == NULL)
return DWFL_E_LIBELF;
result = relocate (r->r_offset, NULL,
GELF_R_TYPE (r->r_info),
GELF_R_SYM (r->r_info));
check_badreltype ();
if (partial)
switch (result)
{
case DWFL_E_NOERROR:
/* We applied the relocation. Elide it. */
memset (&rel_mem, 0, sizeof rel_mem);
gelf_update_rel (reldata, relidx, &rel_mem);
++complete;
break;
case DWFL_E_BADRELTYPE:
case DWFL_E_RELUNDEF:
/* We couldn't handle this relocation. Skip it. */
result = DWFL_E_NOERROR;
break;
default:
break;
}
}
else
for (size_t relidx = 0; !result && relidx < nrels; ++relidx)
{
GElf_Rela rela_mem, *r = gelf_getrela (reldata, relidx,
&rela_mem);
if (r == NULL)
return DWFL_E_LIBELF;
result = relocate (r->r_offset, &r->r_addend,
GELF_R_TYPE (r->r_info),
GELF_R_SYM (r->r_info));
check_badreltype ();
if (partial)
switch (result)
{
case DWFL_E_NOERROR:
/* We applied the relocation. Elide it. */
memset (&rela_mem, 0, sizeof rela_mem);
gelf_update_rela (reldata, relidx, &rela_mem);
++complete;
break;
case DWFL_E_BADRELTYPE:
case DWFL_E_RELUNDEF:
/* We couldn't handle this relocation. Skip it. */
result = DWFL_E_NOERROR;
break;
default:
break;
}
}
if (likely (result == DWFL_E_NOERROR))
{
if (!partial || complete == nrels)
/* Mark this relocation section as being empty now that we have
done its work. This affects unstrip -R, so e.g. it emits an
empty .rela.debug_info along with a .debug_info that has
already been fully relocated. */
nrels = 0;
else if (complete != 0)
{
/* We handled some of the relocations but not all.
We've zeroed out the ones we processed.
Now remove them from the section. */
size_t next = 0;
if (shdr->sh_type == SHT_REL)
for (size_t relidx = 0; relidx < nrels; ++relidx)
{
GElf_Rel rel_mem;
GElf_Rel *r = gelf_getrel (reldata, relidx, &rel_mem);
if (r->r_info != 0 || r->r_offset != 0)
{
if (next != relidx)
gelf_update_rel (reldata, next, r);
++next;
}
}
else
for (size_t relidx = 0; relidx < nrels; ++relidx)
{
GElf_Rela rela_mem;
GElf_Rela *r = gelf_getrela (reldata, relidx, &rela_mem);
if (r->r_info != 0 || r->r_offset != 0 || r->r_addend != 0)
{
if (next != relidx)
gelf_update_rela (reldata, next, r);
++next;
}
}
nrels = next;
}
shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize;
gelf_update_shdr (scn, shdr);
}
return result;
}
Dwfl_Error
internal_function
__libdwfl_relocate (Dwfl_Module *mod, Elf *debugfile, bool debug)
{
assert (mod->e_type == ET_REL);
GElf_Ehdr ehdr_mem;
const GElf_Ehdr *ehdr = gelf_getehdr (debugfile, &ehdr_mem);
if (ehdr == NULL)
return DWFL_E_LIBELF;
size_t d_shstrndx;
if (elf_getshdrstrndx (debugfile, &d_shstrndx) < 0)
return DWFL_E_LIBELF;
RELOC_SYMTAB_CACHE (reloc_symtab);
/* Look at each section in the debuginfo file, and process the
relocation sections for debugging sections. */
Dwfl_Error result = DWFL_E_NOERROR;
Elf_Scn *scn = NULL;
while (result == DWFL_E_NOERROR
&& (scn = elf_nextscn (debugfile, scn)) != NULL)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if ((shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA)
&& shdr->sh_size != 0)
{
/* It's a relocation section. */
Elf_Scn *tscn = elf_getscn (debugfile, shdr->sh_info);
if (unlikely (tscn == NULL))
result = DWFL_E_LIBELF;
else
result = relocate_section (mod, debugfile, ehdr, d_shstrndx,
&reloc_symtab, scn, shdr, tscn,
debug, !debug);
}
}
return result;
}
struct library_symbol *
read_elf(Process *proc) {
struct ltelf lte[MAX_LIBRARIES + 1];
size_t i;
struct opt_x_t *xptr;
struct opt_x_t *opt_x_loc = opt_x;
struct library_symbol **lib_tail = NULL;
int exit_out = 0;
int count = 0;
debug(DEBUG_FUNCTION, "read_elf(file=%s)", proc->filename);
memset(lte, 0, sizeof(lte));
library_symbols = NULL;
library_num = 0;
proc->libdl_hooked = 0;
if (do_init_elf(lte, proc->filename))
return NULL;
memcpy(&main_lte, lte, sizeof(struct ltelf));
if (opt_p && opt_p->pid > 0) {
linkmap_init(proc, lte);
proc->libdl_hooked = 1;
}
proc->e_machine = lte->ehdr.e_machine;
for (i = 0; i < library_num; ++i) {
if (do_init_elf(<e[i + 1], library[i]))
error(EXIT_FAILURE, errno, "Can't open \"%s\"",
library[i]);
}
if (!options.no_plt) {
#ifdef __mips__
// MIPS doesn't use the PLT and the GOT entries get changed
// on startup.
proc->need_to_reinitialize_breakpoints = 1;
for(i=lte->mips_gotsym; i<lte->dynsym_count;i++){
GElf_Sym sym;
const char *name;
GElf_Addr addr = arch_plt_sym_val(lte, i, 0);
if (gelf_getsym(lte->dynsym, i, &sym) == NULL){
error(EXIT_FAILURE, 0,
"Couldn't get relocation from \"%s\"",
proc->filename);
}
name=lte->dynstr+sym.st_name;
if(ELF64_ST_TYPE(sym.st_info) != STT_FUNC){
debug(2,"sym %s not a function",name);
continue;
}
add_library_symbol(addr, name, &library_symbols, 0,
ELF64_ST_BIND(sym.st_info) != 0);
if (!lib_tail)
lib_tail = &(library_symbols->next);
}
#else
for (i = 0; i < lte->relplt_count; ++i) {
GElf_Rel rel;
GElf_Rela rela;
GElf_Sym sym;
GElf_Addr addr;
void *ret;
const char *name;
if (lte->relplt->d_type == ELF_T_REL) {
ret = gelf_getrel(lte->relplt, i, &rel);
rela.r_offset = rel.r_offset;
rela.r_info = rel.r_info;
rela.r_addend = 0;
} else
ret = gelf_getrela(lte->relplt, i, &rela);
if (ret == NULL
|| ELF64_R_SYM(rela.r_info) >= lte->dynsym_count
|| gelf_getsym(lte->dynsym, ELF64_R_SYM(rela.r_info),
&sym) == NULL)
error(EXIT_FAILURE, 0,
"Couldn't get relocation from \"%s\"",
proc->filename);
#ifdef PLT_REINITALISATION_BP
if (!sym.st_value && PLTs_initialized_by_here)
proc->need_to_reinitialize_breakpoints = 1;
#endif
name = lte->dynstr + sym.st_name;
count = library_num ? library_num+1 : 0;
if (in_load_libraries(name, lte, count, NULL)) {
enum toplt pltt;
if (sym.st_value == 0 && lte->plt_stub_vma != 0) {
pltt = LS_TOPLT_EXEC;
addr = lte->plt_stub_vma + PPC_PLT_STUB_SIZE * i;
}
else {
pltt = PLTS_ARE_EXECUTABLE(lte)
? LS_TOPLT_EXEC : LS_TOPLT_POINT;
addr = arch_plt_sym_val(lte, i, &rela);
}
add_library_symbol(addr, name, &library_symbols, pltt,
ELF64_ST_BIND(sym.st_info) == STB_WEAK);
if (!lib_tail)
lib_tail = &(library_symbols->next);
}
}
#endif // !__mips__
#ifdef PLT_REINITALISATION_BP
struct opt_x_t *main_cheat;
if (proc->need_to_reinitialize_breakpoints) {
/* Add "PLTs_initialized_by_here" to opt_x list, if not
already there. */
main_cheat = (struct opt_x_t *)malloc(sizeof(struct opt_x_t));
if (main_cheat == NULL)
error(EXIT_FAILURE, 0, "Couldn't allocate memory");
main_cheat->next = opt_x_loc;
main_cheat->found = 0;
main_cheat->name = PLTs_initialized_by_here;
for (xptr = opt_x_loc; xptr; xptr = xptr->next)
if (strcmp(xptr->name, PLTs_initialized_by_here) == 0
&& main_cheat) {
free(main_cheat);
main_cheat = NULL;
break;
}
if (main_cheat)
opt_x_loc = main_cheat;
}
#endif
} else {
lib_tail = &library_symbols;
}
for (i = 0; i < lte->symtab_count; ++i) {
GElf_Sym sym;
GElf_Addr addr;
const char *name;
if (gelf_getsym(lte->symtab, i, &sym) == NULL)
error(EXIT_FAILURE, 0,
"Couldn't get symbol from \"%s\"",
proc->filename);
name = lte->strtab + sym.st_name;
addr = sym.st_value;
if (!addr)
continue;
for (xptr = opt_x_loc; xptr; xptr = xptr->next)
if (xptr->name && strcmp(xptr->name, name) == 0) {
/* FIXME: Should be able to use &library_symbols as above. But
when you do, none of the real library symbols cause breaks. */
add_library_symbol(opd2addr(lte, addr),
name, lib_tail, LS_TOPLT_NONE, 0);
xptr->found = 1;
break;
}
}
unsigned found_count = 0;
for (xptr = opt_x_loc; xptr; xptr = xptr->next) {
if (xptr->found)
continue;
GElf_Sym sym;
GElf_Addr addr;
if (in_load_libraries(xptr->name, lte, library_num+1, &sym)) {
debug(2, "found symbol %s @ %#" PRIx64 ", adding it.",
xptr->name, sym.st_value);
addr = sym.st_value;
if (ELF32_ST_TYPE (sym.st_info) == STT_FUNC) {
add_library_symbol(addr, xptr->name, lib_tail, LS_TOPLT_NONE, 0);
xptr->found = 1;
found_count++;
}
}
if (found_count == opt_x_cnt){
debug(2, "done, found everything: %d\n", found_count);
break;
}
}
for (xptr = opt_x_loc; xptr; xptr = xptr->next)
if ( ! xptr->found) {
char *badthing = "WARNING";
#ifdef PLT_REINITALISATION_BP
if (strcmp(xptr->name, PLTs_initialized_by_here) == 0) {
if (lte->ehdr.e_entry) {
add_library_symbol (
opd2addr (lte, lte->ehdr.e_entry),
PLTs_initialized_by_here,
lib_tail, 1, 0);
fprintf (stderr, "WARNING: Using e_ent"
"ry from elf header (%p) for "
"address of \"%s\"\n", (void*)
(long) lte->ehdr.e_entry,
PLTs_initialized_by_here);
continue;
}
badthing = "ERROR";
exit_out = 1;
}
#endif
fprintf (stderr,
"%s: Couldn't find symbol \"%s\" in file \"%s\" assuming it will be loaded by libdl!"
"\n", badthing, xptr->name, proc->filename);
}
if (exit_out) {
exit (1);
}
for (i = 0; i < library_num + 1; ++i)
do_close_elf(<e[i]);
return library_symbols;
}
