aadsm created this revision. aadsm added reviewers: clayborg, xiaobai. Herald added subscribers: lldb-commits, mgorny. Herald added a project: LLDB. aadsm added a parent revision: D62499: Create a generic handler for Xfer packets. aadsm added a child revision: D62501: Implement GetSharedLibraryInfoAddress.
This is the second patch to improve module loading in a series that started here (where I explain the motivation and solution): https://reviews.llvm.org/D62499 I need to read the aux vector to know where the r_debug map with the loaded libraries are. We already have a AuxVector class beloging to the POSIX-DYLD plugin but I didn't want to link that lib in. That class also depends on a Process instance which I don't have. I created a new ELFAuxVector that receives a DataExtractor so the data could be really coming from anywhere. I'm not sure if this is the best way to do this, but I do think that a class that only depends on a DataExtractor makes sense. I can get rid of the AuxVector class and use the ELFAuxVector in the POSIX-DYLD (it's really only used in one place) but that also means that we'll have plugins depending on each other and I'm not sure if that's ok. That's the reason why I haven't done this yet. Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D62500 Files: lldb/include/lldb/Host/common/NativeProcessProtocol.h lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp lldb/source/Plugins/Process/Linux/NativeProcessLinux.h lldb/source/Plugins/Process/Utility/CMakeLists.txt lldb/source/Plugins/Process/Utility/ELFAuxVector.cpp lldb/source/Plugins/Process/Utility/ELFAuxVector.h
Index: lldb/source/Plugins/Process/Utility/ELFAuxVector.h =================================================================== --- /dev/null +++ lldb/source/Plugins/Process/Utility/ELFAuxVector.h @@ -0,0 +1,70 @@ +//===-- ELFAuxVector.h ------------------------------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef lldb_ELFAuxVector_h_ +#define lldb_ELFAuxVector_h_ + +#include "lldb/Utility/DataExtractor.h" +#include <unordered_map> + +class ELFAuxVector { + +public: + ELFAuxVector(lldb_private::DataExtractor &data); + + /// Constants describing the type of entry. + /// On Linux, running "LD_SHOW_AUXV=1 ./executable" will spew AUX + /// information. Added AUXV prefix to avoid potential conflicts with system- + /// defined macros + enum EntryType { + AUXV_AT_NULL = 0, ///< End of auxv. + AUXV_AT_IGNORE = 1, ///< Ignore entry. + AUXV_AT_EXECFD = 2, ///< File descriptor of program. + AUXV_AT_PHDR = 3, ///< Program headers. + AUXV_AT_PHENT = 4, ///< Size of program header. + AUXV_AT_PHNUM = 5, ///< Number of program headers. + AUXV_AT_PAGESZ = 6, ///< Page size. + AUXV_AT_BASE = 7, ///< Interpreter base address. + AUXV_AT_FLAGS = 8, ///< Flags. + AUXV_AT_ENTRY = 9, ///< Program entry point. + AUXV_AT_NOTELF = 10, ///< Set if program is not an ELF. + AUXV_AT_UID = 11, ///< UID. + AUXV_AT_EUID = 12, ///< Effective UID. + AUXV_AT_GID = 13, ///< GID. + AUXV_AT_EGID = 14, ///< Effective GID. + AUXV_AT_CLKTCK = 17, ///< Clock frequency (e.g. times(2)). + AUXV_AT_PLATFORM = 15, ///< String identifying platform. + AUXV_AT_HWCAP = + 16, ///< Machine dependent hints about processor capabilities. + AUXV_AT_FPUCW = 18, ///< Used FPU control word. + AUXV_AT_DCACHEBSIZE = 19, ///< Data cache block size. + AUXV_AT_ICACHEBSIZE = 20, ///< Instruction cache block size. + AUXV_AT_UCACHEBSIZE = 21, ///< Unified cache block size. + AUXV_AT_IGNOREPPC = 22, ///< Entry should be ignored. + AUXV_AT_SECURE = 23, ///< Boolean, was exec setuid-like? + AUXV_AT_BASE_PLATFORM = 24, ///< String identifying real platforms. + AUXV_AT_RANDOM = 25, ///< Address of 16 random bytes. + AUXV_AT_EXECFN = 31, ///< Filename of executable. + AUXV_AT_SYSINFO = 32, ///< Pointer to the global system page used for system + /// calls and other nice things. + AUXV_AT_SYSINFO_EHDR = 33, + AUXV_AT_L1I_CACHESHAPE = 34, ///< Shapes of the caches. + AUXV_AT_L1D_CACHESHAPE = 35, + AUXV_AT_L2_CACHESHAPE = 36, + AUXV_AT_L3_CACHESHAPE = 37, + }; + + uint64_t GetAuxValue(enum EntryType entry_type) const; + +private: + void ParseAuxv(lldb_private::DataExtractor &data); + + std::unordered_map<uint64_t, uint64_t> m_auxv_entries; +}; + +#endif Index: lldb/source/Plugins/Process/Utility/ELFAuxVector.cpp =================================================================== --- /dev/null +++ lldb/source/Plugins/Process/Utility/ELFAuxVector.cpp @@ -0,0 +1,43 @@ +//===-- ELFAuxVector.cpp ----------------------------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "ELFAuxVector.h" + +ELFAuxVector::ELFAuxVector(lldb_private::DataExtractor &data) { + ParseAuxv(data); +} + +static bool ReadUInt(lldb_private::DataExtractor &data, + lldb::offset_t *offset_ptr, uint64_t *value) { + lldb::offset_t saved_offset = *offset_ptr; + *value = data.GetMaxU64(offset_ptr, data.GetAddressByteSize()); + return *offset_ptr != saved_offset; +} + +void ELFAuxVector::ParseAuxv(lldb_private::DataExtractor &data) { + lldb::offset_t offset = 0; + while (true) { + uint64_t type = 0; + uint64_t value = 0; + if (!ReadUInt(data, &offset, &type) || !ReadUInt(data, &offset, &value)) + break; + if (type == AUXV_AT_NULL) + break; + if (type == AUXV_AT_IGNORE) + continue; + + m_auxv_entries[type] = value; + } +} + +uint64_t ELFAuxVector::GetAuxValue(enum EntryType entry_type) const { + auto it = m_auxv_entries.find(static_cast<uint64_t>(entry_type)); + if (it != m_auxv_entries.end()) + return it->second; + return 0; +} Index: lldb/source/Plugins/Process/Utility/CMakeLists.txt =================================================================== --- lldb/source/Plugins/Process/Utility/CMakeLists.txt +++ lldb/source/Plugins/Process/Utility/CMakeLists.txt @@ -1,5 +1,6 @@ add_lldb_library(lldbPluginProcessUtility PLUGIN DynamicRegisterInfo.cpp + ELFAuxVector.cpp FreeBSDSignals.cpp GDBRemoteSignals.cpp HistoryThread.cpp Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.h =================================================================== --- lldb/source/Plugins/Process/Linux/NativeProcessLinux.h +++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.h @@ -12,6 +12,7 @@ #include <csignal> #include <unordered_set> +#include "Plugins/Process/Utility/ELFAuxVector.h" #include "lldb/Host/Debug.h" #include "lldb/Host/HostThread.h" #include "lldb/Host/linux/Support.h" @@ -101,6 +102,7 @@ GetAuxvData() const override { return getProcFile(GetID(), "auxv"); } + uint64_t GetAuxValue(enum ELFAuxVector::EntryType type); lldb::user_id_t StartTrace(const TraceOptions &config, Status &error) override; @@ -132,6 +134,7 @@ private: MainLoop::SignalHandleUP m_sigchld_handle; ArchSpec m_arch; + std::unique_ptr<ELFAuxVector> m_aux_vector; LazyBool m_supports_mem_region = eLazyBoolCalculate; std::vector<std::pair<MemoryRegionInfo, FileSpec>> m_mem_region_cache; Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp =================================================================== --- lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp +++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp @@ -2082,3 +2082,17 @@ return error; } + +uint64_t NativeProcessLinux::GetAuxValue(enum ELFAuxVector::EntryType type) { + if (m_aux_vector == nullptr) { + auto buffer_or_error = GetAuxvData(); + if (!buffer_or_error) + return 0; + DataExtractor auxv_data(buffer_or_error.get()->getBufferStart(), + buffer_or_error.get()->getBufferSize(), + GetByteOrder(), GetAddressByteSize()); + m_aux_vector = llvm::make_unique<ELFAuxVector>(auxv_data); + } + + return m_aux_vector->GetAuxValue(type); +} Index: lldb/include/lldb/Host/common/NativeProcessProtocol.h =================================================================== --- lldb/include/lldb/Host/common/NativeProcessProtocol.h +++ lldb/include/lldb/Host/common/NativeProcessProtocol.h @@ -133,6 +133,10 @@ return GetArchitecture().GetByteOrder(); } + uint32_t GetAddressByteSize() const { + return GetArchitecture().GetAddressByteSize(); + } + virtual llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> GetAuxvData() const = 0;
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