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- /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- * list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- #include <Kernel/FileSystem/FileDescription.h>
- #include <Kernel/FileSystem/VirtualFileSystem.h>
- #include <Kernel/KSyms.h>
- #include <Kernel/Module.h>
- #include <Kernel/Process.h>
- #include <LibELF/Loader.h>
- namespace Kernel {
- extern HashMap<String, OwnPtr<Module>>* g_modules;
- int Process::sys$module_load(Userspace<const char*> user_path, size_t path_length)
- {
- if (!is_superuser())
- return -EPERM;
- REQUIRE_NO_PROMISES;
- auto path = get_syscall_path_argument(user_path, path_length);
- if (path.is_error())
- return path.error();
- auto description_or_error = VFS::the().open(path.value(), O_RDONLY, 0, current_directory());
- if (description_or_error.is_error())
- return description_or_error.error();
- auto& description = description_or_error.value();
- auto payload_or_error = description->read_entire_file();
- if (payload_or_error.is_error())
- return payload_or_error.error();
- auto payload = payload_or_error.value();
- auto storage = KBuffer::create_with_size(payload.size());
- memcpy(storage.data(), payload.data(), payload.size());
- auto elf_image = make<ELF::Image>(storage.data(), storage.size());
- if (!elf_image->parse())
- return -ENOEXEC;
- HashMap<String, u8*> section_storage_by_name;
- auto module = make<Module>();
- elf_image->for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
- if (!section.size())
- return IterationDecision::Continue;
- auto section_storage = KBuffer::copy(section.raw_data(), section.size(), Region::Access::Read | Region::Access::Write | Region::Access::Execute);
- section_storage_by_name.set(section.name(), section_storage.data());
- module->sections.append(move(section_storage));
- return IterationDecision::Continue;
- });
- bool missing_symbols = false;
- elf_image->for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
- if (!section.size())
- return IterationDecision::Continue;
- auto* section_storage = section_storage_by_name.get(section.name()).value_or(nullptr);
- ASSERT(section_storage);
- section.relocations().for_each_relocation([&](const ELF::Image::Relocation& relocation) {
- auto& patch_ptr = *reinterpret_cast<ptrdiff_t*>(section_storage + relocation.offset());
- switch (relocation.type()) {
- case R_386_PC32: {
- // PC-relative relocation
- dbg() << "PC-relative relocation: " << relocation.symbol().name();
- u32 symbol_address = address_for_kernel_symbol(relocation.symbol().name());
- if (symbol_address == 0)
- missing_symbols = true;
- dbg() << " Symbol address: " << (void*)symbol_address;
- ptrdiff_t relative_offset = (char*)symbol_address - ((char*)&patch_ptr + 4);
- patch_ptr = relative_offset;
- break;
- }
- case R_386_32: // Absolute relocation
- dbg() << "Absolute relocation: '" << relocation.symbol().name() << "' value:" << relocation.symbol().value() << ", index:" << relocation.symbol_index();
- if (relocation.symbol().bind() == STB_LOCAL) {
- auto* section_storage_containing_symbol = section_storage_by_name.get(relocation.symbol().section().name()).value_or(nullptr);
- ASSERT(section_storage_containing_symbol);
- u32 symbol_address = (ptrdiff_t)(section_storage_containing_symbol + relocation.symbol().value());
- if (symbol_address == 0)
- missing_symbols = true;
- dbg() << " Symbol address: " << (void*)symbol_address;
- patch_ptr += symbol_address;
- } else if (relocation.symbol().bind() == STB_GLOBAL) {
- u32 symbol_address = address_for_kernel_symbol(relocation.symbol().name());
- if (symbol_address == 0)
- missing_symbols = true;
- dbg() << " Symbol address: " << (void*)symbol_address;
- patch_ptr += symbol_address;
- } else {
- ASSERT_NOT_REACHED();
- }
- break;
- }
- return IterationDecision::Continue;
- });
- return IterationDecision::Continue;
- });
- if (missing_symbols)
- return -EINVAL;
- auto* text_base = section_storage_by_name.get(".text").value_or(nullptr);
- if (!text_base) {
- dbg() << "No .text section found in module!";
- return -EINVAL;
- }
- elf_image->for_each_symbol([&](const ELF::Image::Symbol& symbol) {
- dbg() << " - " << symbol.type() << " '" << symbol.name() << "' @ " << (void*)symbol.value() << ", size=" << symbol.size();
- if (symbol.name() == "module_init") {
- module->module_init = (ModuleInitPtr)(text_base + symbol.value());
- } else if (symbol.name() == "module_fini") {
- module->module_fini = (ModuleFiniPtr)(text_base + symbol.value());
- } else if (symbol.name() == "module_name") {
- const u8* storage = section_storage_by_name.get(symbol.section().name()).value_or(nullptr);
- if (storage)
- module->name = String((const char*)(storage + symbol.value()));
- }
- return IterationDecision::Continue;
- });
- if (!module->module_init)
- return -EINVAL;
- if (g_modules->contains(module->name)) {
- dbg() << "a module with the name " << module->name << " is already loaded; please unload it first";
- return -EEXIST;
- }
- module->module_init();
- auto name = module->name;
- g_modules->set(name, move(module));
- return 0;
- }
- int Process::sys$module_unload(Userspace<const char*> user_name, size_t name_length)
- {
- if (!is_superuser())
- return -EPERM;
- REQUIRE_NO_PROMISES;
- auto module_name = validate_and_copy_string_from_user(user_name, name_length);
- if (module_name.is_null())
- return -EFAULT;
- auto it = g_modules->find(module_name);
- if (it == g_modules->end())
- return -ENOENT;
- if (it->value->module_fini)
- it->value->module_fini();
- g_modules->remove(it);
- return 0;
- }
- }
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