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am 86f594b1: Merge "Encapsulate soinfo_link_image and soinfo_relocate"

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* commit '86f594b19bc51ffe87bfacb6b42687af94c3c648':
  Encapsulate soinfo_link_image and soinfo_relocate
This commit is contained in:
Dmitriy Ivanov 2014-09-02 19:45:29 +00:00 committed by Android Git Automerger
commit a1d14f62f6
2 changed files with 149 additions and 154 deletions
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297
linker/linker.cpp
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@ -79,7 +79,6 @@ static const char* get_base_name(const char* name) {
#define SEARCH_NAME(x) get_base_name(x)
#endif
static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo);
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
static LinkerAllocator<soinfo> g_soinfo_allocator;
@ -509,7 +508,7 @@ static unsigned elfhash(const char* _name) {
return h;
}
static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, soinfo* needed[]) {
static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi) {
unsigned elf_hash = elfhash(name);
ElfW(Sym)* s = nullptr;
@ -604,15 +603,15 @@ static ElfW(Sym)* soinfo_do_lookup(soinfo* si, const char* name, soinfo** lsi, s
}
}
for (int i = 0; needed[i] != nullptr; i++) {
DEBUG("%s: looking up %s in %s",
si->name, name, needed[i]->name);
s = soinfo_elf_lookup(needed[i], elf_hash, name);
si->get_children().visit([&](soinfo* child) {
DEBUG("%s: looking up %s in %s", si->name, name, child->name);
s = soinfo_elf_lookup(child, elf_hash, name);
if (s != nullptr) {
*lsi = needed[i];
goto done;
*lsi = child;
return false;
}
}
return true;
});
done:
if (s != nullptr) {
@ -860,7 +859,7 @@ static soinfo* load_library(const char* name, int dlflags, const android_dlextin
TRACE("[ load_library base=%p size=%zu name='%s' ]",
reinterpret_cast<void*>(si->base), si->size, si->name);
if (!soinfo_link_image(si, extinfo)) {
if (!si->LinkImage(extinfo)) {
soinfo_free(si);
return nullptr;
}
@ -1001,7 +1000,7 @@ void do_dlclose(soinfo* si) {
// ifuncs are only defined for x86
#if defined(__i386__)
static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* needed[]) {
static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count) {
for (size_t idx = 0; idx < count; ++idx, ++rel) {
ElfW(Sym)* s;
soinfo* lsi;
@ -1011,7 +1010,7 @@ static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, so
ElfW(Addr) sym_addr = 0;
const char* sym_name = nullptr;
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
s = soinfo_do_lookup(si, sym_name, &lsi);
if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC && type == R_386_JMP_SLOT) {
TRACE("IFUNC RELOCATION, PASS 2: %p", (void*)(sym_addr));
@ -1024,7 +1023,7 @@ static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, so
#endif
#if defined(__x86_64__)
static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo* needed[]) {
static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count) {
for (size_t idx = 0; idx < count; ++idx, ++rela) {
ElfW(Sym)* s;
soinfo* lsi;
@ -1034,7 +1033,7 @@ static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count,
ElfW(Addr) sym_addr = 0;
const char* sym_name = nullptr;
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
s = soinfo_do_lookup(si, sym_name, &lsi);
if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC && type == R_X86_64_JUMP_SLOT) {
TRACE("IFUNC RELOCATION, PASS 2: %p", (void*)(sym_addr + rela->r_addend));
@ -1047,29 +1046,29 @@ static void soinfo_ifunc_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count,
#endif
#if defined(USE_RELA)
static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo* needed[]) {
int soinfo::Relocate(ElfW(Rela)* rela, unsigned count) {
ElfW(Sym)* s;
soinfo* lsi;
for (size_t idx = 0; idx < count; ++idx, ++rela) {
unsigned type = ELFW(R_TYPE)(rela->r_info);
unsigned sym = ELFW(R_SYM)(rela->r_info);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rela->r_offset + si->load_bias);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rela->r_offset + load_bias);
ElfW(Addr) sym_addr = 0;
const char* sym_name = nullptr;
DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
DEBUG("Processing '%s' relocation at index %zd", name, idx);
if (type == 0) { // R_*_NONE
continue;
}
if (sym != 0) {
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
sym_name = reinterpret_cast<const char*>(strtab + symtab[sym].st_name);
s = soinfo_do_lookup(this, sym_name, &lsi);
if (s == nullptr) {
// We only allow an undefined symbol if this is a weak reference...
s = &si->symtab[sym];
s = &symtab[sym];
if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, si->name);
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, name);
return -1;
}
@ -1227,8 +1226,8 @@ static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo*
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %16llx <- %16llx\n",
reloc, (si->base + rela->r_addend));
*reinterpret_cast<ElfW(Addr)*>(reloc) = (si->base + rela->r_addend);
reloc, (base + rela->r_addend));
*reinterpret_cast<ElfW(Addr)*>(reloc) = (base + rela->r_addend);
break;
case R_AARCH64_COPY:
@ -1241,7 +1240,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo*
* R_AARCH64_COPY may only appear in executable objects where e_type is
* set to ET_EXEC.
*/
DL_ERR("%s R_AARCH64_COPY relocations are not supported", si->name);
DL_ERR("%s R_AARCH64_COPY relocations are not supported", name);
return -1;
case R_AARCH64_TLS_TPREL64:
TRACE_TYPE(RELO, "RELO TLS_TPREL64 *** %16llx <- %16llx - %16llx\n",
@ -1258,7 +1257,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo*
TRACE_TYPE(RELO, "RELO JMP_SLOT %08zx <- %08zx %s", static_cast<size_t>(reloc),
static_cast<size_t>(sym_addr + rela->r_addend), sym_name);
if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) {
si->set_has_ifuncs(true);
set_has_ifuncs(true);
} else {
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr + rela->r_addend;
}
@ -1278,8 +1277,8 @@ static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo*
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %08zx <- +%08zx", static_cast<size_t>(reloc),
static_cast<size_t>(si->base));
*reinterpret_cast<ElfW(Addr)*>(reloc) = si->base + rela->r_addend;
static_cast<size_t>(base));
*reinterpret_cast<ElfW(Addr)*>(reloc) = base + rela->r_addend;
break;
case R_X86_64_32:
count_relocation(kRelocRelative);
@ -1314,8 +1313,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rela)* rela, unsigned count, soinfo*
}
#else // REL, not RELA.
static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* needed[]) {
int soinfo::Relocate(ElfW(Rel)* rel, unsigned count) {
ElfW(Sym)* s;
soinfo* lsi;
@ -1323,22 +1321,22 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
unsigned type = ELFW(R_TYPE)(rel->r_info);
// TODO: don't use unsigned for 'sym'. Use uint32_t or ElfW(Addr) instead.
unsigned sym = ELFW(R_SYM)(rel->r_info);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + si->load_bias);
ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + load_bias);
ElfW(Addr) sym_addr = 0;
const char* sym_name = nullptr;
DEBUG("Processing '%s' relocation at index %zd", si->name, idx);
DEBUG("Processing '%s' relocation at index %zd", name, idx);
if (type == 0) { // R_*_NONE
continue;
}
if (sym != 0) {
sym_name = reinterpret_cast<const char*>(si->strtab + si->symtab[sym].st_name);
s = soinfo_do_lookup(si, sym_name, &lsi, needed);
sym_name = reinterpret_cast<const char*>(strtab + symtab[sym].st_name);
s = soinfo_do_lookup(this, sym_name, &lsi);
if (s == nullptr) {
// We only allow an undefined symbol if this is a weak reference...
s = &si->symtab[sym];
s = &symtab[sym];
if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, si->name);
DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, name);
return -1;
}
@ -1433,7 +1431,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
* R_ARM_COPY may only appear in executable objects where e_type is
* set to ET_EXEC.
*/
DL_ERR("%s R_ARM_COPY relocations are not supported", si->name);
DL_ERR("%s R_ARM_COPY relocations are not supported", name);
return -1;
#elif defined(__i386__)
case R_386_JMP_SLOT:
@ -1441,7 +1439,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
MARK(rel->r_offset);
TRACE_TYPE(RELO, "RELO JMP_SLOT %08x <- %08x %s", reloc, sym_addr, sym_name);
if (ELF_ST_TYPE(s->st_info) == STT_GNU_IFUNC) {
si->set_has_ifuncs(true);
set_has_ifuncs(true);
} else {
*reinterpret_cast<ElfW(Addr)*>(reloc) = sym_addr;
}
@ -1485,7 +1483,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
if (s) {
*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
} else {
*reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
*reinterpret_cast<ElfW(Addr)*>(reloc) += base;
}
break;
#endif
@ -1502,8 +1500,8 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
return -1;
}
TRACE_TYPE(RELO, "RELO RELATIVE %p <- +%p",
reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(si->base));
*reinterpret_cast<ElfW(Addr)*>(reloc) += si->base;
reinterpret_cast<void*>(reloc), reinterpret_cast<void*>(base));
*reinterpret_cast<ElfW(Addr)*>(reloc) += base;
break;
default:
@ -1516,7 +1514,7 @@ static int soinfo_relocate(soinfo* si, ElfW(Rel)* rel, unsigned count, soinfo* n
#endif
#if defined(__mips__)
static bool mips_relocate_got(soinfo* si, soinfo* needed[]) {
static bool mips_relocate_got(soinfo* si) {
ElfW(Addr)** got = si->plt_got;
if (got == nullptr) {
return true;
@ -1549,7 +1547,7 @@ static bool mips_relocate_got(soinfo* si, soinfo* needed[]) {
// This is an undefined reference... try to locate it.
const char* sym_name = si->strtab + sym->st_name;
soinfo* lsi;
ElfW(Sym)* s = soinfo_do_lookup(si, sym_name, &lsi, needed);
ElfW(Sym)* s = soinfo_do_lookup(si, sym_name, &lsi);
if (s == nullptr) {
// We only allow an undefined symbol if this is a weak reference.
s = &symtab[g];
@ -1803,84 +1801,80 @@ static int nullify_closed_stdio() {
return return_value;
}
static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
/* "base" might wrap around UINT32_MAX. */
ElfW(Addr) base = si->load_bias;
const ElfW(Phdr)* phdr = si->phdr;
int phnum = si->phnum;
bool relocating_linker = (si->flags & FLAG_LINKER) != 0;
bool soinfo::LinkImage(const android_dlextinfo* extinfo) {
bool relocating_linker = (flags & FLAG_LINKER) != 0;
/* We can't debug anything until the linker is relocated */
if (!relocating_linker) {
INFO("[ linking %s ]", si->name);
DEBUG("si->base = %p si->flags = 0x%08x", reinterpret_cast<void*>(si->base), si->flags);
INFO("[ linking %s ]", name);
DEBUG("si->base = %p si->flags = 0x%08x", reinterpret_cast<void*>(base), flags);
}
/* Extract dynamic section */
size_t dynamic_count;
ElfW(Word) dynamic_flags;
phdr_table_get_dynamic_section(phdr, phnum, base, &si->dynamic,
phdr_table_get_dynamic_section(phdr, phnum, load_bias, &dynamic,
&dynamic_count, &dynamic_flags);
if (si->dynamic == nullptr) {
if (dynamic == nullptr) {
if (!relocating_linker) {
DL_ERR("missing PT_DYNAMIC in \"%s\"", si->name);
DL_ERR("missing PT_DYNAMIC in \"%s\"", name);
}
return false;
} else {
if (!relocating_linker) {
DEBUG("dynamic = %p", si->dynamic);
DEBUG("dynamic = %p", dynamic);
}
}
#if defined(__arm__)
(void) phdr_table_get_arm_exidx(phdr, phnum, base,
&si->ARM_exidx, &si->ARM_exidx_count);
(void) phdr_table_get_arm_exidx(phdr, phnum, load_bias,
&ARM_exidx, &ARM_exidx_count);
#endif
// Extract useful information from dynamic section.
uint32_t needed_count = 0;
for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
DEBUG("d = %p, d[0](tag) = %p d[1](val) = %p",
d, reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
switch (d->d_tag) {
case DT_HASH:
si->nbucket = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr)[0];
si->nchain = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr)[1];
si->bucket = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr + 8);
si->chain = reinterpret_cast<uint32_t*>(base + d->d_un.d_ptr + 8 + si->nbucket * 4);
nbucket = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr)[0];
nchain = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr)[1];
bucket = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr + 8);
chain = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr + 8 + nbucket * 4);
break;
case DT_STRTAB:
si->strtab = reinterpret_cast<const char*>(base + d->d_un.d_ptr);
strtab = reinterpret_cast<const char*>(load_bias + d->d_un.d_ptr);
break;
case DT_SYMTAB:
si->symtab = reinterpret_cast<ElfW(Sym)*>(base + d->d_un.d_ptr);
symtab = reinterpret_cast<ElfW(Sym)*>(load_bias + d->d_un.d_ptr);
break;
#if !defined(__LP64__)
case DT_PLTREL:
if (d->d_un.d_val != DT_REL) {
DL_ERR("unsupported DT_RELA in \"%s\"", si->name);
DL_ERR("unsupported DT_RELA in \"%s\"", name);
return false;
}
break;
#endif
case DT_JMPREL:
#if defined(USE_RELA)
si->plt_rela = reinterpret_cast<ElfW(Rela)*>(base + d->d_un.d_ptr);
plt_rela = reinterpret_cast<ElfW(Rela)*>(load_bias + d->d_un.d_ptr);
#else
si->plt_rel = reinterpret_cast<ElfW(Rel)*>(base + d->d_un.d_ptr);
plt_rel = reinterpret_cast<ElfW(Rel)*>(load_bias + d->d_un.d_ptr);
#endif
break;
case DT_PLTRELSZ:
#if defined(USE_RELA)
si->plt_rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
plt_rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
#else
si->plt_rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
plt_rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
#endif
break;
#if defined(__mips__)
case DT_PLTGOT:
// Used by mips and mips64.
si->plt_got = reinterpret_cast<ElfW(Addr)**>(base + d->d_un.d_ptr);
plt_got = reinterpret_cast<ElfW(Addr)**>(load_bias + d->d_un.d_ptr);
break;
#endif
case DT_DEBUG:
@ -1898,67 +1892,67 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
#endif
#if defined(USE_RELA)
case DT_RELA:
si->rela = reinterpret_cast<ElfW(Rela)*>(base + d->d_un.d_ptr);
rela = reinterpret_cast<ElfW(Rela)*>(load_bias + d->d_un.d_ptr);
break;
case DT_RELASZ:
si->rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
break;
case DT_REL:
DL_ERR("unsupported DT_REL in \"%s\"", si->name);
DL_ERR("unsupported DT_REL in \"%s\"", name);
return false;
case DT_RELSZ:
DL_ERR("unsupported DT_RELSZ in \"%s\"", si->name);
DL_ERR("unsupported DT_RELSZ in \"%s\"", name);
return false;
#else
case DT_REL:
si->rel = reinterpret_cast<ElfW(Rel)*>(base + d->d_un.d_ptr);
rel = reinterpret_cast<ElfW(Rel)*>(load_bias + d->d_un.d_ptr);
break;
case DT_RELSZ:
si->rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
break;
case DT_RELA:
DL_ERR("unsupported DT_RELA in \"%s\"", si->name);
DL_ERR("unsupported DT_RELA in \"%s\"", name);
return false;
#endif
case DT_INIT:
si->init_func = reinterpret_cast<linker_function_t>(base + d->d_un.d_ptr);
DEBUG("%s constructors (DT_INIT) found at %p", si->name, si->init_func);
init_func = reinterpret_cast<linker_function_t>(load_bias + d->d_un.d_ptr);
DEBUG("%s constructors (DT_INIT) found at %p", name, init_func);
break;
case DT_FINI:
si->fini_func = reinterpret_cast<linker_function_t>(base + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI) found at %p", si->name, si->fini_func);
fini_func = reinterpret_cast<linker_function_t>(load_bias + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI) found at %p", name, fini_func);
break;
case DT_INIT_ARRAY:
si->init_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s constructors (DT_INIT_ARRAY) found at %p", si->name, si->init_array);
init_array = reinterpret_cast<linker_function_t*>(load_bias + d->d_un.d_ptr);
DEBUG("%s constructors (DT_INIT_ARRAY) found at %p", name, init_array);
break;
case DT_INIT_ARRAYSZ:
si->init_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
init_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
break;
case DT_FINI_ARRAY:
si->fini_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI_ARRAY) found at %p", si->name, si->fini_array);
fini_array = reinterpret_cast<linker_function_t*>(load_bias + d->d_un.d_ptr);
DEBUG("%s destructors (DT_FINI_ARRAY) found at %p", name, fini_array);
break;
case DT_FINI_ARRAYSZ:
si->fini_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
fini_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
break;
case DT_PREINIT_ARRAY:
si->preinit_array = reinterpret_cast<linker_function_t*>(base + d->d_un.d_ptr);
DEBUG("%s constructors (DT_PREINIT_ARRAY) found at %p", si->name, si->preinit_array);
preinit_array = reinterpret_cast<linker_function_t*>(load_bias + d->d_un.d_ptr);
DEBUG("%s constructors (DT_PREINIT_ARRAY) found at %p", name, preinit_array);
break;
case DT_PREINIT_ARRAYSZ:
si->preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
preinit_array_count = ((unsigned)d->d_un.d_val) / sizeof(ElfW(Addr));
break;
case DT_TEXTREL:
#if defined(__LP64__)
DL_ERR("text relocations (DT_TEXTREL) found in 64-bit ELF file \"%s\"", si->name);
DL_ERR("text relocations (DT_TEXTREL) found in 64-bit ELF file \"%s\"", name);
return false;
#else
si->has_text_relocations = true;
has_text_relocations = true;
break;
#endif
case DT_SYMBOLIC:
si->has_DT_SYMBOLIC = true;
has_DT_SYMBOLIC = true;
break;
case DT_NEEDED:
++needed_count;
@ -1966,14 +1960,14 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
case DT_FLAGS:
if (d->d_un.d_val & DF_TEXTREL) {
#if defined(__LP64__)
DL_ERR("text relocations (DF_TEXTREL) found in 64-bit ELF file \"%s\"", si->name);
DL_ERR("text relocations (DF_TEXTREL) found in 64-bit ELF file \"%s\"", name);
return false;
#else
si->has_text_relocations = true;
has_text_relocations = true;
#endif
}
if (d->d_un.d_val & DF_SYMBOLIC) {
si->has_DT_SYMBOLIC = true;
has_DT_SYMBOLIC = true;
}
break;
#if defined(__mips__)
@ -1984,7 +1978,7 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
case DT_MIPS_RLD_MAP:
// Set the DT_MIPS_RLD_MAP entry to the address of _r_debug for GDB.
{
r_debug** dp = reinterpret_cast<r_debug**>(base + d->d_un.d_ptr);
r_debug** dp = reinterpret_cast<r_debug**>(load_bias + d->d_un.d_ptr);
*dp = &_r_debug;
}
break;
@ -1995,15 +1989,15 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
break;
case DT_MIPS_SYMTABNO:
si->mips_symtabno = d->d_un.d_val;
mips_symtabno = d->d_un.d_val;
break;
case DT_MIPS_LOCAL_GOTNO:
si->mips_local_gotno = d->d_un.d_val;
mips_local_gotno = d->d_un.d_val;
break;
case DT_MIPS_GOTSYM:
si->mips_gotsym = d->d_un.d_val;
mips_gotsym = d->d_un.d_val;
break;
#endif
@ -2015,28 +2009,28 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
}
DEBUG("si->base = %p, si->strtab = %p, si->symtab = %p",
reinterpret_cast<void*>(si->base), si->strtab, si->symtab);
reinterpret_cast<void*>(base), strtab, symtab);
// Sanity checks.
if (relocating_linker && needed_count != 0) {
DL_ERR("linker cannot have DT_NEEDED dependencies on other libraries");
return false;
}
if (si->nbucket == 0) {
DL_ERR("empty/missing DT_HASH in \"%s\" (built with --hash-style=gnu?)", si->name);
if (nbucket == 0) {
DL_ERR("empty/missing DT_HASH in \"%s\" (built with --hash-style=gnu?)", name);
return false;
}
if (si->strtab == 0) {
DL_ERR("empty/missing DT_STRTAB in \"%s\"", si->name);
if (strtab == 0) {
DL_ERR("empty/missing DT_STRTAB in \"%s\"", name);
return false;
}
if (si->symtab == 0) {
DL_ERR("empty/missing DT_SYMTAB in \"%s\"", si->name);
if (symtab == 0) {
DL_ERR("empty/missing DT_SYMTAB in \"%s\"", name);
return false;
}
// If this is the main executable, then load all of the libraries from LD_PRELOAD now.
if (si->flags & FLAG_EXE) {
if (flags & FLAG_EXE) {
memset(g_ld_preloads, 0, sizeof(g_ld_preloads));
size_t preload_count = 0;
for (size_t i = 0; g_ld_preload_names[i] != nullptr; i++) {
@ -2046,69 +2040,64 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
} else {
// As with glibc, failure to load an LD_PRELOAD library is just a warning.
DL_WARN("could not load library \"%s\" from LD_PRELOAD for \"%s\"; caused by %s",
g_ld_preload_names[i], si->name, linker_get_error_buffer());
g_ld_preload_names[i], name, linker_get_error_buffer());
}
}
}
soinfo** needed = reinterpret_cast<soinfo**>(alloca((1 + needed_count) * sizeof(soinfo*)));
soinfo** pneeded = needed;
for (ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
DEBUG("%s needs %s", si->name, library_name);
const char* library_name = strtab + d->d_un.d_val;
DEBUG("%s needs %s", name, library_name);
soinfo* lsi = find_library(library_name, 0, nullptr);
if (lsi == nullptr) {
strlcpy(tmp_err_buf, linker_get_error_buffer(), sizeof(tmp_err_buf));
DL_ERR("could not load library \"%s\" needed by \"%s\"; caused by %s",
library_name, si->name, tmp_err_buf);
library_name, name, tmp_err_buf);
return false;
}
si->add_child(lsi);
*pneeded++ = lsi;
add_child(lsi);
}
}
*pneeded = nullptr;
#if !defined(__LP64__)
if (si->has_text_relocations) {
if (has_text_relocations) {
// Make segments writable to allow text relocations to work properly. We will later call
// phdr_table_protect_segments() after all of them are applied and all constructors are run.
DL_WARN("%s has text relocations. This is wasting memory and prevents "
"security hardening. Please fix.", si->name);
if (phdr_table_unprotect_segments(si->phdr, si->phnum, si->load_bias) < 0) {
"security hardening. Please fix.", name);
if (phdr_table_unprotect_segments(phdr, phnum, load_bias) < 0) {
DL_ERR("can't unprotect loadable segments for \"%s\": %s",
si->name, strerror(errno));
name, strerror(errno));
return false;
}
}
#endif
#if defined(USE_RELA)
if (si->plt_rela != nullptr) {
DEBUG("[ relocating %s plt ]\n", si->name);
if (soinfo_relocate(si, si->plt_rela, si->plt_rela_count, needed)) {
if (plt_rela != nullptr) {
DEBUG("[ relocating %s plt ]\n", name);
if (Relocate(plt_rela, plt_rela_count)) {
return false;
}
}
if (si->rela != nullptr) {
DEBUG("[ relocating %s ]\n", si->name);
if (soinfo_relocate(si, si->rela, si->rela_count, needed)) {
if (rela != nullptr) {
DEBUG("[ relocating %s ]\n", name);
if (Relocate(rela, rela_count)) {
return false;
}
}
#else
if (si->plt_rel != nullptr) {
DEBUG("[ relocating %s plt ]", si->name);
if (soinfo_relocate(si, si->plt_rel, si->plt_rel_count, needed)) {
if (plt_rel != nullptr) {
DEBUG("[ relocating %s plt ]", name);
if (Relocate(plt_rel, plt_rel_count)) {
return false;
}
}
if (si->rel != nullptr) {
DEBUG("[ relocating %s ]", si->name);
if (soinfo_relocate(si, si->rel, si->rel_count, needed)) {
if (rel != nullptr) {
DEBUG("[ relocating %s ]", name);
if (Relocate(rel, rel_count)) {
return false;
}
}
@ -2118,59 +2107,59 @@ static bool soinfo_link_image(soinfo* si, const android_dlextinfo* extinfo) {
// they cannot be resolved until the rest of the relocations are done
// because we need to call the resolution function which may be waiting
// on relocations.
if(si->get_has_ifuncs()) {
if(get_has_ifuncs()) {
#if defined(__i386__)
soinfo_ifunc_relocate(si, si->plt_rel, si->plt_rel_count, needed);
soinfo_ifunc_relocate(this, plt_rel, plt_rel_count);
#elif defined(__x86_64__)
soinfo_ifunc_relocate(si, si->plt_rela, si->plt_rela_count, needed);
soinfo_ifunc_relocate(this, plt_rela, plt_rela_count);
#endif
}
#if defined(__mips__)
if (!mips_relocate_got(si, needed)) {
if (!mips_relocate_got(this)) {
return false;
}
#endif
si->flags |= FLAG_LINKED;
DEBUG("[ finished linking %s ]", si->name);
flags |= FLAG_LINKED;
DEBUG("[ finished linking %s ]", name);
#if !defined(__LP64__)
if (si->has_text_relocations) {
if (has_text_relocations) {
// All relocations are done, we can protect our segments back to read-only.
if (phdr_table_protect_segments(si->phdr, si->phnum, si->load_bias) < 0) {
if (phdr_table_protect_segments(phdr, phnum, load_bias) < 0) {
DL_ERR("can't protect segments for \"%s\": %s",
si->name, strerror(errno));
name, strerror(errno));
return false;
}
}
#endif
/* We can also turn on GNU RELRO protection */
if (phdr_table_protect_gnu_relro(si->phdr, si->phnum, si->load_bias) < 0) {
if (phdr_table_protect_gnu_relro(phdr, phnum, load_bias) < 0) {
DL_ERR("can't enable GNU RELRO protection for \"%s\": %s",
si->name, strerror(errno));
name, strerror(errno));
return false;
}
/* Handle serializing/sharing the RELRO segment */
if (extinfo && (extinfo->flags & ANDROID_DLEXT_WRITE_RELRO)) {
if (phdr_table_serialize_gnu_relro(si->phdr, si->phnum, si->load_bias,
if (phdr_table_serialize_gnu_relro(phdr, phnum, load_bias,
extinfo->relro_fd) < 0) {
DL_ERR("failed serializing GNU RELRO section for \"%s\": %s",
si->name, strerror(errno));
name, strerror(errno));
return false;
}
} else if (extinfo && (extinfo->flags & ANDROID_DLEXT_USE_RELRO)) {
if (phdr_table_map_gnu_relro(si->phdr, si->phnum, si->load_bias,
if (phdr_table_map_gnu_relro(phdr, phnum, load_bias,
extinfo->relro_fd) < 0) {
DL_ERR("failed mapping GNU RELRO section for \"%s\": %s",
si->name, strerror(errno));
name, strerror(errno));
return false;
}
}
notify_gdb_of_load(si);
notify_gdb_of_load(this);
return true;
}
@ -2194,7 +2183,7 @@ static void add_vdso(KernelArgumentBlock& args __unused) {
si->size = phdr_table_get_load_size(si->phdr, si->phnum);
si->load_bias = get_elf_exec_load_bias(ehdr_vdso);
soinfo_link_image(si, nullptr);
si->LinkImage(nullptr);
#endif
}
@ -2323,7 +2312,7 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
somain = si;
if (!soinfo_link_image(si, nullptr)) {
if (!si->LinkImage(nullptr)) {
__libc_format_fd(2, "CANNOT LINK EXECUTABLE: %s\n", linker_get_error_buffer());
exit(EXIT_FAILURE);
}
@ -2336,7 +2325,7 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
g_ld_preloads[i]->CallConstructors();
}
/* After the link_image, the si->load_bias is initialized.
/* After the LinkImage, the si->load_bias is initialized.
* For so lib, the map->l_addr will be updated in notify_gdb_of_load.
* We need to update this value for so exe here. So Unwind_Backtrace
* for some arch like x86 could work correctly within so exe.
@ -2451,7 +2440,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
linker_so.phnum = elf_hdr->e_phnum;
linker_so.flags |= FLAG_LINKER;
if (!soinfo_link_image(&linker_so, nullptr)) {
if (!linker_so.LinkImage(nullptr)) {
// It would be nice to print an error message, but if the linker
// can't link itself, there's no guarantee that we'll be able to
// call write() (because it involves a GOT reference). We may as

6
linker/linker.h
View File

@ -204,6 +204,7 @@ struct soinfo {
void CallConstructors();
void CallDestructors();
void CallPreInitConstructors();
bool LinkImage(const android_dlextinfo* extinfo);
void add_child(soinfo* child);
void remove_all_links();
@ -224,6 +225,11 @@ struct soinfo {
void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse);
void CallFunction(const char* function_name, linker_function_t function);
void resolve_ifunc_symbols();
#if defined(USE_RELA)
int Relocate(ElfW(Rela)* rela, unsigned count);
#else
int Relocate(ElfW(Rel)* rel, unsigned count);
#endif
private:
// This part of the structure is only available