169 lines
6.4 KiB
C++
169 lines
6.4 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "linker.h"
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#include "linker_debug.h"
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#include "linker_relocs.h"
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#include "linker_reloc_iterators.h"
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#include "linker_leb128.h"
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template bool soinfo::relocate<plain_reloc_iterator>(plain_reloc_iterator&& rel_iterator,
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const soinfo_list_t& global_group,
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const soinfo_list_t& local_group);
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template bool soinfo::relocate<packed_reloc_iterator<sleb128_decoder>>(
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packed_reloc_iterator<sleb128_decoder>&& rel_iterator,
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const soinfo_list_t& global_group,
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const soinfo_list_t& local_group);
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template bool soinfo::relocate<packed_reloc_iterator<leb128_decoder>>(
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packed_reloc_iterator<leb128_decoder>&& rel_iterator,
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const soinfo_list_t& global_group,
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const soinfo_list_t& local_group);
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template <typename ElfRelIteratorT>
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bool soinfo::relocate(ElfRelIteratorT&& rel_iterator,
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const soinfo_list_t& global_group,
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const soinfo_list_t& local_group) {
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for (size_t idx = 0; rel_iterator.has_next(); ++idx) {
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const auto rel = rel_iterator.next();
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if (rel == nullptr) {
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return false;
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}
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ElfW(Word) type = ELFW(R_TYPE)(rel->r_info);
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ElfW(Word) sym = ELFW(R_SYM)(rel->r_info);
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ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + load_bias);
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ElfW(Addr) sym_addr = 0;
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const char* sym_name = nullptr;
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DEBUG("Processing '%s' relocation at index %zd", this->name, idx);
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if (type == R_GENERIC_NONE) {
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continue;
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}
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ElfW(Sym)* s = nullptr;
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soinfo* lsi = nullptr;
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if (sym != 0) {
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sym_name = get_string(symtab_[sym].st_name);
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s = soinfo_do_lookup(this, sym_name, &lsi, global_group,local_group);
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if (s == nullptr) {
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// mips does not support relocation with weak-undefined symbols
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DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", sym_name, name);
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return false;
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} else {
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// We got a definition.
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sym_addr = lsi->resolve_symbol_address(s);
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}
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count_relocation(kRelocSymbol);
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}
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switch (type) {
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case R_MIPS_REL32:
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#if defined(__LP64__)
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// MIPS Elf64_Rel entries contain compound relocations
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// We only handle the R_MIPS_NONE|R_MIPS_64|R_MIPS_REL32 case
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if (ELF64_R_TYPE2(rel->r_info) != R_MIPS_64 ||
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ELF64_R_TYPE3(rel->r_info) != R_MIPS_NONE) {
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DL_ERR("Unexpected compound relocation type:%d type2:%d type3:%d @ %p (%zu)",
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type, static_cast<unsigned>(ELF64_R_TYPE2(rel->r_info)),
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static_cast<unsigned>(ELF64_R_TYPE3(rel->r_info)), rel, idx);
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return false;
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}
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#endif
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count_relocation(s == nullptr ? kRelocAbsolute : kRelocRelative);
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MARK(rel->r_offset);
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TRACE_TYPE(RELO, "RELO REL32 %08zx <- %08zx %s", static_cast<size_t>(reloc),
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static_cast<size_t>(sym_addr), sym_name ? sym_name : "*SECTIONHDR*");
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if (s != nullptr) {
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*reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr;
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} else {
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*reinterpret_cast<ElfW(Addr)*>(reloc) += base;
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}
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break;
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default:
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DL_ERR("unknown reloc type %d @ %p (%zu)", type, rel, idx);
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return false;
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}
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}
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return true;
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}
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bool soinfo::mips_relocate_got(const soinfo_list_t& global_group,
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const soinfo_list_t& local_group) {
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ElfW(Addr)** got = plt_got_;
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if (got == nullptr) {
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return true;
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}
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// got[0] is the address of the lazy resolver function.
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// got[1] may be used for a GNU extension.
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// Set it to a recognizable address in case someone calls it (should be _rtld_bind_start).
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// FIXME: maybe this should be in a separate routine?
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if ((flags_ & FLAG_LINKER) == 0) {
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size_t g = 0;
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got[g++] = reinterpret_cast<ElfW(Addr)*>(0xdeadbeef);
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if (reinterpret_cast<intptr_t>(got[g]) < 0) {
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got[g++] = reinterpret_cast<ElfW(Addr)*>(0xdeadfeed);
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}
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// Relocate the local GOT entries.
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for (; g < mips_local_gotno_; g++) {
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got[g] = reinterpret_cast<ElfW(Addr)*>(reinterpret_cast<uintptr_t>(got[g]) + load_bias);
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}
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}
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// Now for the global GOT entries...
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ElfW(Sym)* sym = symtab_ + mips_gotsym_;
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got = plt_got_ + mips_local_gotno_;
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for (size_t g = mips_gotsym_; g < mips_symtabno_; g++, sym++, got++) {
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// This is an undefined reference... try to locate it.
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const char* sym_name = get_string(sym->st_name);
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soinfo* lsi = nullptr;
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ElfW(Sym)* s = soinfo_do_lookup(this, sym_name, &lsi, global_group, local_group);
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if (s == nullptr) {
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// We only allow an undefined symbol if this is a weak reference.
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s = &symtab_[g];
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if (ELF_ST_BIND(s->st_info) != STB_WEAK) {
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DL_ERR("cannot locate \"%s\"...", sym_name);
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return false;
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}
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*got = 0;
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} else {
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// FIXME: is this sufficient?
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// For reference see NetBSD link loader
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// http://cvsweb.netbsd.org/bsdweb.cgi/src/libexec/ld.elf_so/arch/mips/mips_reloc.c?rev=1.53&content-type=text/x-cvsweb-markup
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*got = reinterpret_cast<ElfW(Addr)*>(lsi->resolve_symbol_address(s));
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}
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}
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return true;
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}
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