static int symb_synthesize_plt_symbols(struct symb_arr *arr, Elf *elf) {
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
uint64_t plt_offset;
GElf_Shdr shdr_plt;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
Elf_Data *reldata, *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
int nr = 0, symidx, err = 0;
if (gelf_getehdr(elf, &ehdr) == NULL)
goto out_elf_end;
scn_dynsym
= elf_section_by_name(elf, &ehdr, &shdr_dynsym, ".dynsym", &dynsym_idx);
if (scn_dynsym == NULL)
goto out_elf_end;
scn_plt_rel
= elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rela.plt", NULL);
if (scn_plt_rel == NULL) {
scn_plt_rel
= elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rel.plt", NULL);
if (scn_plt_rel == NULL)
goto out_elf_end;
}
err = -1;
if (shdr_rel_plt.sh_link != dynsym_idx)
goto out_elf_end;
if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
goto out_elf_end;
/*
* Fetch the relocation section to find the idxes to the GOT
* and the symbols in the .dynsym they refer to.
*/
reldata = elf_getdata(scn_plt_rel, NULL);
if (reldata == NULL)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
if (syms == NULL)
goto out_elf_end;
scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
if (scn_symstrs == NULL)
goto out_elf_end;
symstrs = elf_getdata(scn_symstrs, NULL);
if (symstrs == NULL)
goto out_elf_end;
nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
if (shdr_rel_plt.sh_type == SHT_RELA) {
GElf_Rela pos_mem, *pos;
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_sym__name(&sym, symstrs));
struct symb *s = symb_new();
s->hex = plt_offset;
s->name = strdup(sympltname);
symb_insert(s, arr);
++nr;
}
/*
* We need to check if we have a .dynsym, so that we can handle the
* .plt, synthesizing its symbols, that aren't on the symtabs (be it
* .dynsym or .symtab).
* And always look at the original dso, not at debuginfo packages, that
* have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
*/
int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
symbol_filter_t filter)
{
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
u64 plt_offset;
GElf_Shdr shdr_plt;
struct symbol *f;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
Elf_Data *reldata, *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
Elf *elf;
int nr = 0, symidx, err = 0;
if (!ss->dynsym)
return 0;
elf = ss->elf;
ehdr = ss->ehdr;
scn_dynsym = ss->dynsym;
shdr_dynsym = ss->dynshdr;
dynsym_idx = ss->dynsym_idx;
if (scn_dynsym == NULL)
goto out_elf_end;
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rela.plt", NULL);
if (scn_plt_rel == NULL) {
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rel.plt", NULL);
if (scn_plt_rel == NULL)
goto out_elf_end;
}
err = -1;
if (shdr_rel_plt.sh_link != dynsym_idx)
goto out_elf_end;
if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
goto out_elf_end;
/*
* Fetch the relocation section to find the idxes to the GOT
* and the symbols in the .dynsym they refer to.
*/
reldata = elf_getdata(scn_plt_rel, NULL);
if (reldata == NULL)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
if (syms == NULL)
goto out_elf_end;
scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
if (scn_symstrs == NULL)
goto out_elf_end;
symstrs = elf_getdata(scn_symstrs, NULL);
if (symstrs == NULL)
goto out_elf_end;
if (symstrs->d_size == 0)
goto out_elf_end;
nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
if (shdr_rel_plt.sh_type == SHT_RELA) {
GElf_Rela pos_mem, *pos;
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_sym__name(&sym, symstrs));
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
STB_GLOBAL, sympltname);
if (!f)
goto out_elf_end;
if (filter && filter(map, f))
symbol__delete(f);
else {
symbols__insert(&dso->symbols[map->type], f);
++nr;
}
}
/*
* We need to check if we have a .dynsym, so that we can handle the
* .plt, synthesizing its symbols, that aren't on the symtabs (be it
* .dynsym or .symtab).
* And always look at the original dso, not at debuginfo packages, that
* have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
*/
static int dso__synthesize_plt_symbols(struct dso *self, int verbose)
{
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
u64 plt_offset;
GElf_Shdr shdr_plt;
struct symbol *f;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
Elf_Data *reldata, *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
Elf *elf;
int nr = 0, symidx, fd, err = 0;
fd = open(self->name, O_RDONLY);
if (fd < 0)
goto out;
elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
if (elf == NULL)
goto out_close;
if (gelf_getehdr(elf, &ehdr) == NULL)
goto out_elf_end;
scn_dynsym = elf_section_by_name(elf, &ehdr, &shdr_dynsym,
".dynsym", &dynsym_idx);
if (scn_dynsym == NULL)
goto out_elf_end;
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rela.plt", NULL);
if (scn_plt_rel == NULL) {
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rel.plt", NULL);
if (scn_plt_rel == NULL)
goto out_elf_end;
}
err = -1;
if (shdr_rel_plt.sh_link != dynsym_idx)
goto out_elf_end;
if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
goto out_elf_end;
/*
* Fetch the relocation section to find the indexes to the GOT
* and the symbols in the .dynsym they refer to.
*/
reldata = elf_getdata(scn_plt_rel, NULL);
if (reldata == NULL)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
if (syms == NULL)
goto out_elf_end;
scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
if (scn_symstrs == NULL)
goto out_elf_end;
symstrs = elf_getdata(scn_symstrs, NULL);
if (symstrs == NULL)
goto out_elf_end;
nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
if (shdr_rel_plt.sh_type == SHT_RELA) {
GElf_Rela pos_mem, *pos;
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_sym__name(&sym, symstrs));
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
sympltname, self->sym_priv_size, 0, verbose);
if (!f)
goto out_elf_end;
dso__insert_symbol(self, f);
++nr;
}
