| // Copyright 2019 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "starboard/elf_loader/program_table.h" |
| |
| #include <sys/mman.h> |
| |
| #include "starboard/common/log.h" |
| #include "starboard/common/string.h" |
| #include "starboard/elf_loader/evergreen_info.h" |
| #include "starboard/elf_loader/log.h" |
| #include "starboard/memory.h" |
| #include "starboard/string.h" |
| |
| #define MAYBE_MAP_FLAG(x, from, to) (((x) & (from)) ? (to) : 0) |
| |
| #define PFLAGS_TO_PROT(x) \ |
| (MAYBE_MAP_FLAG((x), PF_X, PROT_EXEC) | \ |
| MAYBE_MAP_FLAG((x), PF_R, PROT_READ) | \ |
| MAYBE_MAP_FLAG((x), PF_W, PROT_WRITE)) |
| |
| namespace starboard { |
| namespace elf_loader { |
| |
| ProgramTable::ProgramTable( |
| const CobaltExtensionMemoryMappedFileApi* memory_mapped_file_extension) |
| : phdr_num_(0), |
| phdr_mmap_(NULL), |
| phdr_table_(NULL), |
| phdr_size_(0), |
| load_start_(NULL), |
| load_size_(0), |
| base_memory_address_(0), |
| memory_mapped_file_extension_(memory_mapped_file_extension) { |
| #if SB_API_VERSION >= 16 |
| SB_CHECK(kSbCanMapExecutableMemory) |
| << "This module requires executable memory support!"; |
| #else |
| #if !SB_CAN(MAP_EXECUTABLE_MEMORY) |
| SB_CHECK(false) << "This module requires " |
| "executable memory map support!"; |
| #endif |
| #endif |
| } |
| |
| bool ProgramTable::LoadProgramHeader(const Ehdr* elf_header, File* elf_file) { |
| if (!elf_header) { |
| SB_LOG(ERROR) << "Ehdr is required"; |
| return false; |
| } |
| if (!elf_file) { |
| SB_LOG(ERROR) << "File is required"; |
| return false; |
| } |
| phdr_num_ = elf_header->e_phnum; |
| |
| SB_DLOG(INFO) << "Program Header count=" << phdr_num_; |
| // Like the kernel, only accept program header tables smaller than 64 KB. |
| if (phdr_num_ < 1 || phdr_num_ > 65536 / elf_header->e_phentsize) { |
| SB_LOG(ERROR) << "Invalid program header count: " << phdr_num_; |
| return false; |
| } |
| |
| SB_DLOG(INFO) << "elf_header->e_phoff=" << elf_header->e_phoff; |
| SB_DLOG(INFO) << "elf_header->e_phnum=" << elf_header->e_phnum; |
| |
| Addr page_min = PAGE_START(elf_header->e_phoff); |
| Addr page_max = |
| PAGE_END(elf_header->e_phoff + (phdr_num_ * elf_header->e_phentsize)); |
| Addr page_offset = PAGE_OFFSET(elf_header->e_phoff); |
| |
| SB_DLOG(INFO) << "page_min=" << page_min; |
| SB_DLOG(INFO) << "page_max=" << page_max; |
| |
| phdr_size_ = page_max - page_min; |
| |
| SB_DLOG(INFO) << "page_max - page_min=" << page_max - page_min; |
| |
| if (memory_mapped_file_extension_) { |
| SB_LOG(INFO) << "Using memory mapped file for the program header"; |
| phdr_mmap_ = memory_mapped_file_extension_->MemoryMapFile( |
| NULL, elf_file->GetName().c_str(), kSbMemoryMapProtectRead, page_min, |
| phdr_size_); |
| if (!phdr_mmap_) { |
| SB_LOG(ERROR) << "Failed to memory map the program header"; |
| return false; |
| } |
| |
| SB_DLOG(INFO) << "Allocated address=" << phdr_mmap_; |
| } else { |
| phdr_mmap_ = |
| mmap(nullptr, phdr_size_, PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); |
| if (!phdr_mmap_) { |
| SB_LOG(ERROR) << "Failed to allocate memory"; |
| return false; |
| } |
| |
| SB_DLOG(INFO) << "Allocated address=" << phdr_mmap_; |
| if (!elf_file->ReadFromOffset(page_min, reinterpret_cast<char*>(phdr_mmap_), |
| phdr_size_)) { |
| SB_LOG(ERROR) << "Failed to read program header from file offset: " |
| << page_min; |
| return false; |
| } |
| bool mp_result = mprotect(phdr_mmap_, phdr_size_, PROT_READ) == 0; |
| SB_DLOG(INFO) << "mp_result=" << mp_result; |
| if (!mp_result) { |
| SB_LOG(ERROR) << "Failed to protect program header"; |
| return false; |
| } |
| } |
| |
| phdr_table_ = reinterpret_cast<Phdr*>(reinterpret_cast<char*>(phdr_mmap_) + |
| page_offset); |
| SB_DLOG(INFO) << "phdr_table_=" << phdr_table_; |
| return true; |
| } |
| |
| static bool ElfClassBuildIDNoteIdentifier(const void* section, |
| size_t length, |
| std::vector<uint8_t>& identifier) { |
| const void* section_end = reinterpret_cast<const char*>(section) + length; |
| const Nhdr* note_header = reinterpret_cast<const Nhdr*>(section); |
| while (reinterpret_cast<const void*>(note_header) < section_end) { |
| if (note_header->n_type == NT_GNU_BUILD_ID) |
| break; |
| note_header = reinterpret_cast<const Nhdr*>( |
| reinterpret_cast<const char*>(note_header) + sizeof(Nhdr) + |
| NOTE_PADDING(note_header->n_namesz) + |
| NOTE_PADDING(note_header->n_descsz)); |
| } |
| if (reinterpret_cast<const void*>(note_header) >= section_end || |
| note_header->n_descsz == 0) { |
| return false; |
| } |
| |
| const uint8_t* build_id = reinterpret_cast<const uint8_t*>(note_header) + |
| sizeof(Nhdr) + NOTE_PADDING(note_header->n_namesz); |
| identifier.insert(identifier.end(), build_id, |
| build_id + note_header->n_descsz); |
| |
| return true; |
| } |
| |
| bool ProgramTable::LoadSegments(File* elf_file) { |
| for (size_t i = 0; i < phdr_num_; ++i) { |
| const Phdr* phdr = &phdr_table_[i]; |
| |
| if (phdr->p_type == PT_NOTE) { |
| if (!ElfClassBuildIDNoteIdentifier( |
| reinterpret_cast<const void*>(phdr->p_vaddr + |
| base_memory_address_), |
| phdr->p_memsz, build_id_)) { |
| SB_LOG(INFO) << "Could not get build id"; |
| } |
| continue; |
| } |
| if (phdr->p_type != PT_LOAD) { |
| continue; |
| } |
| |
| // Segment byte addresses in memory. |
| Addr seg_start = phdr->p_vaddr + base_memory_address_; |
| Addr seg_end = seg_start + phdr->p_memsz; |
| |
| // Segment page addresses in memory. |
| Addr seg_page_start = PAGE_START(seg_start); |
| Addr seg_page_end = PAGE_END(seg_end); |
| |
| // File offsets. |
| Addr seg_file_end = seg_start + phdr->p_filesz; |
| Addr file_start = phdr->p_offset; |
| Addr file_end = file_start + phdr->p_filesz; |
| |
| SB_DLOG(INFO) << " phdr->p_offset=" << phdr->p_offset |
| << " phdr->p_filesz=" << phdr->p_filesz; |
| |
| Addr file_page_start = PAGE_START(file_start); |
| Addr file_length = file_end - file_page_start; |
| |
| SB_DLOG(INFO) << "Mapping segment: " << " file_page_start=" |
| << file_page_start << " file_length=" << file_length |
| << " seg_page_start=0x" << std::hex << seg_page_start; |
| |
| if (file_length != 0) { |
| const int prot_flags = PFLAGS_TO_PROT(phdr->p_flags); |
| SB_DLOG(INFO) << "segment prot_flags=" << std::hex << prot_flags; |
| |
| void* seg_addr = reinterpret_cast<void*>(seg_page_start); |
| bool mp_ret = false; |
| if (memory_mapped_file_extension_) { |
| SB_DLOG(INFO) << "Using Memory Mapped File for Loading the Segment"; |
| void* p = memory_mapped_file_extension_->MemoryMapFile( |
| seg_addr, elf_file->GetName().c_str(), kSbMemoryMapProtectRead, |
| file_page_start, file_length); |
| if (!p) { |
| SB_LOG(ERROR) << "Failed to memory map file: " << elf_file->GetName(); |
| return false; |
| } |
| } else { |
| SB_DLOG(INFO) << "Not using Memory Mapped Files"; |
| mp_ret = mprotect(seg_addr, file_length, PROT_WRITE) == 0; |
| SB_DLOG(INFO) << "segment vaddress=" << seg_addr; |
| |
| if (!mp_ret) { |
| SB_LOG(ERROR) << "Failed to unprotect segment"; |
| return false; |
| } |
| if (!elf_file->ReadFromOffset(file_page_start, |
| reinterpret_cast<char*>(seg_addr), |
| file_length)) { |
| SB_DLOG(INFO) << "Failed to read segment from file offset: " |
| << file_page_start; |
| return false; |
| } |
| } |
| mp_ret = mprotect(seg_addr, file_length, prot_flags) == 0; |
| SB_DLOG(INFO) << "mp_ret=" << mp_ret; |
| if (!mp_ret) { |
| SB_LOG(ERROR) << "Failed to protect segment"; |
| return false; |
| } |
| if (!seg_addr) { |
| SB_LOG(ERROR) << "Could not map segment " << i; |
| return false; |
| } |
| } |
| |
| // if the segment is writable, and does not end on a page boundary, |
| // zero-fill it until the page limit. |
| if ((phdr->p_flags & PF_W) != 0 && PAGE_OFFSET(seg_file_end) > 0) { |
| memset(reinterpret_cast<void*>(seg_file_end), 0, |
| PAGE_SIZE - PAGE_OFFSET(seg_file_end)); |
| } |
| |
| seg_file_end = PAGE_END(seg_file_end); |
| |
| // seg_file_end is now the first page address after the file |
| // content. If seg_page_end is larger, we need to zero anything |
| // between them. This is done by using a private anonymous |
| // map for all extra pages. |
| if (seg_page_end > seg_file_end) { |
| bool mprotect_fix = |
| mprotect(reinterpret_cast<void*>(seg_file_end), |
| seg_page_end - seg_file_end, PROT_WRITE) == 0; |
| SB_DLOG(INFO) << "mprotect_fix=" << mprotect_fix; |
| if (!mprotect_fix) { |
| SB_LOG(ERROR) << "Failed to unprotect end of segment"; |
| return false; |
| } |
| |
| memset(reinterpret_cast<void*>(seg_file_end), 0, |
| seg_page_end - seg_file_end); |
| mprotect(reinterpret_cast<void*>(seg_file_end), |
| seg_page_end - seg_file_end, PFLAGS_TO_PROT(phdr->p_flags)); |
| SB_DLOG(INFO) << "mprotect_fix=" << mprotect_fix; |
| if (!mprotect_fix) { |
| SB_LOG(ERROR) << "Failed to protect end of segment"; |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| size_t ProgramTable::GetLoadMemorySize() { |
| Addr min_vaddr = ~static_cast<Addr>(0); |
| Addr max_vaddr = 0x00000000U; |
| |
| bool found_pt_load = false; |
| for (size_t i = 0; i < phdr_num_; ++i) { |
| const Phdr* phdr = &phdr_table_[i]; |
| |
| if (phdr->p_type != PT_LOAD) { |
| SB_DLOG(INFO) << "GetLoadMemorySize: ignoring segment with type: " |
| << phdr->p_type; |
| continue; |
| } |
| found_pt_load = true; |
| |
| if (phdr->p_vaddr < min_vaddr) { |
| SB_DLOG(INFO) << "p_vaddr=" << std::hex << phdr->p_vaddr; |
| min_vaddr = phdr->p_vaddr; |
| } |
| |
| if (phdr->p_vaddr + phdr->p_memsz > max_vaddr) { |
| max_vaddr = phdr->p_vaddr + phdr->p_memsz; |
| SB_DLOG(INFO) << "phdr->p_vaddr=" << phdr->p_vaddr |
| << " phdr->p_memsz=" << phdr->p_memsz; |
| SB_DLOG(INFO) << " max_vaddr=0x" << std::hex << max_vaddr; |
| } |
| } |
| if (!found_pt_load) { |
| min_vaddr = 0x00000000U; |
| } |
| |
| min_vaddr = PAGE_START(min_vaddr); |
| max_vaddr = PAGE_END(max_vaddr); |
| |
| return max_vaddr - min_vaddr; |
| } |
| |
| void ProgramTable::GetDynamicSection(Dyn** dynamic, |
| size_t* dynamic_count, |
| Word* dynamic_flags) { |
| const Phdr* phdr = phdr_table_; |
| const Phdr* phdr_limit = phdr + phdr_num_; |
| |
| for (phdr = phdr_table_; phdr < phdr_limit; phdr++) { |
| if (phdr->p_type != PT_DYNAMIC) { |
| SB_DLOG(INFO) << "Ignore section with type: " << phdr->p_type; |
| continue; |
| } |
| |
| SB_DLOG(INFO) << "Reading at vaddr: " << phdr->p_vaddr; |
| *dynamic = reinterpret_cast<Dyn*>(base_memory_address_ + phdr->p_vaddr); |
| if (dynamic_count) { |
| *dynamic_count = static_cast<size_t>((phdr->p_memsz / sizeof(Dyn))); |
| } |
| if (dynamic_flags) { |
| *dynamic_flags = phdr->p_flags; |
| } |
| return; |
| } |
| *dynamic = NULL; |
| if (dynamic_count) { |
| *dynamic_count = 0; |
| } |
| } |
| |
| int ProgramTable::AdjustMemoryProtectionOfReadOnlySegments( |
| int extra_prot_flags) { |
| const Phdr* phdr = phdr_table_; |
| const Phdr* phdr_limit = phdr + phdr_num_; |
| |
| for (; phdr < phdr_limit; phdr++) { |
| if (phdr->p_type != PT_LOAD || (phdr->p_flags & PF_W) != 0) |
| continue; |
| |
| Addr seg_page_start = PAGE_START(phdr->p_vaddr) + base_memory_address_; |
| Addr seg_page_end = |
| PAGE_END(phdr->p_vaddr + phdr->p_memsz) + base_memory_address_; |
| int ret = mprotect(reinterpret_cast<void*>(seg_page_start), |
| seg_page_end - seg_page_start, |
| PFLAGS_TO_PROT(phdr->p_flags) | extra_prot_flags); |
| if (ret < 0) { |
| return -1; |
| } |
| } |
| return 0; |
| } |
| |
| bool ProgramTable::ReserveLoadMemory() { |
| load_size_ = GetLoadMemorySize(); |
| if (load_size_ == 0) { |
| SB_LOG(ERROR) << "No loadable segments"; |
| return false; |
| } |
| |
| SB_DLOG(INFO) << "Load size=" << load_size_; |
| |
| load_start_ = |
| mmap(nullptr, load_size_, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0); |
| if (load_start_ == MAP_FAILED) { |
| SB_LOG(ERROR) << "Could not reserve " << load_size_ |
| << " bytes of address space"; |
| return false; |
| } |
| base_memory_address_ = reinterpret_cast<Addr>(load_start_); |
| SB_LOG(INFO) << "Load start=" << std::hex << load_start_ |
| << " base_memory_address=0x" << base_memory_address_; |
| return true; |
| } |
| |
| void ProgramTable::PublishEvergreenInfo(const char* file_path) { |
| EvergreenInfo evergreen_info; |
| memset(&evergreen_info, 0, sizeof(EvergreenInfo)); |
| starboard::strlcpy(evergreen_info.file_path_buf, file_path, |
| EVERGREEN_FILE_PATH_MAX_SIZE); |
| evergreen_info.base_address = base_memory_address_; |
| evergreen_info.load_size = load_size_; |
| evergreen_info.phdr_table = (uint64_t)phdr_table_; |
| evergreen_info.phdr_table_num = phdr_num_; |
| |
| std::vector<char> tmp(build_id_.begin(), build_id_.end()); |
| tmp.push_back('\0'); |
| starboard::strlcpy(evergreen_info.build_id, tmp.data(), |
| EVERGREEN_BUILD_ID_MAX_SIZE); |
| evergreen_info.build_id_length = build_id_.size(); |
| |
| SetEvergreenInfo(&evergreen_info); |
| } |
| |
| Addr ProgramTable::GetBaseMemoryAddress() { |
| return base_memory_address_; |
| } |
| |
| ProgramTable::~ProgramTable() { |
| SetEvergreenInfo(NULL); |
| if (load_start_) { |
| munmap(load_start_, load_size_); |
| } |
| if (phdr_mmap_) { |
| munmap(phdr_mmap_, phdr_size_); |
| } |
| } |
| |
| } // namespace elf_loader |
| } // namespace starboard |
