From 3b872b89d18b31ed24830e91f323eeae324af166 Mon Sep 17 00:00:00 2001 From: Liam Date: Sat, 11 Nov 2023 10:41:06 -0500 Subject: [PATCH] gdbstub: read module information from memory layout --- src/core/debugger/gdbstub.cpp | 165 ++++++++++++++++++++++++---------- 1 file changed, 118 insertions(+), 47 deletions(-) diff --git a/src/core/debugger/gdbstub.cpp b/src/core/debugger/gdbstub.cpp index e9bf57895..148dd3e39 100644 --- a/src/core/debugger/gdbstub.cpp +++ b/src/core/debugger/gdbstub.cpp @@ -562,6 +562,120 @@ static std::string PaginateBuffer(std::string_view buffer, std::string_view requ } } +static VAddr GetModuleEnd(Kernel::KProcessPageTable& page_table, VAddr base) { + Kernel::KMemoryInfo mem_info; + Kernel::Svc::MemoryInfo svc_mem_info; + Kernel::Svc::PageInfo page_info; + VAddr cur_addr{base}; + + // Expect: r-x Code (.text) + R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); + svc_mem_info = mem_info.GetSvcMemoryInfo(); + cur_addr = svc_mem_info.base_address + svc_mem_info.size; + if (svc_mem_info.state != Kernel::Svc::MemoryState::Code || + svc_mem_info.permission != Kernel::Svc::MemoryPermission::ReadExecute) { + return cur_addr - 1; + } + + // Expect: r-- Code (.rodata) + R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); + svc_mem_info = mem_info.GetSvcMemoryInfo(); + cur_addr = svc_mem_info.base_address + svc_mem_info.size; + if (svc_mem_info.state != Kernel::Svc::MemoryState::Code || + svc_mem_info.permission != Kernel::Svc::MemoryPermission::Read) { + return cur_addr - 1; + } + + // Expect: rw- CodeData (.data) + R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); + svc_mem_info = mem_info.GetSvcMemoryInfo(); + cur_addr = svc_mem_info.base_address + svc_mem_info.size; + return cur_addr - 1; +} + +static Loader::AppLoader::Modules FindModules(Core::System& system) { + Loader::AppLoader::Modules modules; + + auto& page_table = system.ApplicationProcess()->GetPageTable(); + auto& memory = system.ApplicationMemory(); + VAddr cur_addr = 0; + + // Look for executable sections in Code or AliasCode regions. + while (true) { + Kernel::KMemoryInfo mem_info{}; + Kernel::Svc::PageInfo page_info{}; + R_ASSERT( + page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); + auto svc_mem_info = mem_info.GetSvcMemoryInfo(); + + if (svc_mem_info.permission == Kernel::Svc::MemoryPermission::ReadExecute && + (svc_mem_info.state == Kernel::Svc::MemoryState::Code || + svc_mem_info.state == Kernel::Svc::MemoryState::AliasCode)) { + // Try to read the module name from its path. + constexpr s32 PathLengthMax = 0x200; + struct { + u32 zero; + s32 path_length; + std::array path; + } module_path; + + if (memory.ReadBlock(svc_mem_info.base_address + svc_mem_info.size, &module_path, + sizeof(module_path))) { + if (module_path.zero == 0 && module_path.path_length > 0) { + // Truncate module name. + module_path.path[PathLengthMax - 1] = '\0'; + + // Ignore leading directories. + char* path_pointer = module_path.path.data(); + + for (s32 i = 0; i < std::min(PathLengthMax, module_path.path_length) && + module_path.path[i] != '\0'; + i++) { + if (module_path.path[i] == '/' || module_path.path[i] == '\\') { + path_pointer = module_path.path.data() + i + 1; + } + } + + // Insert output. + modules.emplace(svc_mem_info.base_address, path_pointer); + } + } + } + + // Check if we're done. + const uintptr_t next_address = svc_mem_info.base_address + svc_mem_info.size; + if (next_address <= cur_addr) { + break; + } + + cur_addr = next_address; + } + + return modules; +} + +static VAddr FindMainModuleEntrypoint(Core::System& system) { + Loader::AppLoader::Modules modules; + system.GetAppLoader().ReadNSOModules(modules); + + // Do we have a module named main? + const auto main = std::find_if(modules.begin(), modules.end(), + [](const auto& key) { return key.second == "main"; }); + + if (main != modules.end()) { + return main->first; + } + + // Do we have any loaded executable sections? + modules = FindModules(system); + if (!modules.empty()) { + return modules.begin()->first; + } + + // As a last resort, use the start of the code region. + return GetInteger(system.ApplicationProcess()->GetPageTable().GetCodeRegionStart()); +} + void GDBStub::HandleQuery(std::string_view command) { if (command.starts_with("TStatus")) { // no tracepoint support @@ -573,21 +687,10 @@ void GDBStub::HandleQuery(std::string_view command) { const auto target_xml{arch->GetTargetXML()}; SendReply(PaginateBuffer(target_xml, command.substr(30))); } else if (command.starts_with("Offsets")) { - Loader::AppLoader::Modules modules; - system.GetAppLoader().ReadNSOModules(modules); - - const auto main = std::find_if(modules.begin(), modules.end(), - [](const auto& key) { return key.second == "main"; }); - if (main != modules.end()) { - SendReply(fmt::format("TextSeg={:x}", main->first)); - } else { - SendReply(fmt::format( - "TextSeg={:x}", - GetInteger(system.ApplicationProcess()->GetPageTable().GetCodeRegionStart()))); - } + const auto main_offset = FindMainModuleEntrypoint(system); + SendReply(fmt::format("TextSeg={:x}", main_offset)); } else if (command.starts_with("Xfer:libraries:read::")) { - Loader::AppLoader::Modules modules; - system.GetAppLoader().ReadNSOModules(modules); + auto modules = FindModules(system); std::string buffer; buffer += R"()"; @@ -727,37 +830,6 @@ static constexpr const char* GetMemoryPermissionString(const Kernel::Svc::Memory } } -static VAddr GetModuleEnd(Kernel::KProcessPageTable& page_table, VAddr base) { - Kernel::KMemoryInfo mem_info; - Kernel::Svc::MemoryInfo svc_mem_info; - Kernel::Svc::PageInfo page_info; - VAddr cur_addr{base}; - - // Expect: r-x Code (.text) - R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); - svc_mem_info = mem_info.GetSvcMemoryInfo(); - cur_addr = svc_mem_info.base_address + svc_mem_info.size; - if (svc_mem_info.state != Kernel::Svc::MemoryState::Code || - svc_mem_info.permission != Kernel::Svc::MemoryPermission::ReadExecute) { - return cur_addr - 1; - } - - // Expect: r-- Code (.rodata) - R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); - svc_mem_info = mem_info.GetSvcMemoryInfo(); - cur_addr = svc_mem_info.base_address + svc_mem_info.size; - if (svc_mem_info.state != Kernel::Svc::MemoryState::Code || - svc_mem_info.permission != Kernel::Svc::MemoryPermission::Read) { - return cur_addr - 1; - } - - // Expect: rw- CodeData (.data) - R_ASSERT(page_table.QueryInfo(std::addressof(mem_info), std::addressof(page_info), cur_addr)); - svc_mem_info = mem_info.GetSvcMemoryInfo(); - cur_addr = svc_mem_info.base_address + svc_mem_info.size; - return cur_addr - 1; -} - void GDBStub::HandleRcmd(const std::vector& command) { std::string_view command_str{reinterpret_cast(&command[0]), command.size()}; std::string reply; @@ -784,8 +856,7 @@ void GDBStub::HandleRcmd(const std::vector& command) { reply = "Fastmem is not enabled.\n"; } } else if (command_str == "get info") { - Loader::AppLoader::Modules modules; - system.GetAppLoader().ReadNSOModules(modules); + auto modules = FindModules(system); reply = fmt::format("Process: {:#x} ({})\n" "Program Id: {:#018x}\n",