diff options
Diffstat (limited to 'Kernel/Syscalls/module.cpp')
| -rw-r--r-- | Kernel/Syscalls/module.cpp | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/Kernel/Syscalls/module.cpp b/Kernel/Syscalls/module.cpp new file mode 100644 index 0000000000..85d0ef49b8 --- /dev/null +++ b/Kernel/Syscalls/module.cpp @@ -0,0 +1,188 @@ +/* + * 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(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()); + payload.clear(); + + 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(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; +} + +} |