From fb785877a95d5d51e802df618b22187b624a2b23 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= Date: Sat, 18 Dec 2021 10:09:12 +0100 Subject: [PATCH] [lldb] [Process/FreeBSDKernel] Introduce libkvm support Introduce initial support for using libkvm on FreeBSD. The library can be used as an alternate implementation for processing kernel coredumps but it can also be used to access live kernel memory through specifying "/dev/mem" as the core file, i.e.: lldb --core /dev/mem /boot/kernel/kernel Differential Revision: https://reviews.llvm.org/D116005 --- .../Process/FreeBSDKernel/CMakeLists.txt | 12 +- .../FreeBSDKernel/ProcessFreeBSDKernel.cpp | 146 ++++++++++++++---- .../FreeBSDKernel/ProcessFreeBSDKernel.h | 11 +- .../FreeBSDKernel/TestFreeBSDKernelLive.py | 44 ++++++ 4 files changed, 174 insertions(+), 39 deletions(-) create mode 100644 lldb/test/API/functionalities/postmortem/FreeBSDKernel/TestFreeBSDKernelLive.py diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt b/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt index ad388ee76b07..ca89ab0b6dc9 100644 --- a/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt +++ b/lldb/source/Plugins/Process/FreeBSDKernel/CMakeLists.txt @@ -1,4 +1,12 @@ -if (NOT FBSDVMCore_FOUND) +set(FBSDKERNEL_LIBS) +if(FBSDVMCore_FOUND) + list(APPEND FBSDKERNEL_LIBS fbsdvmcore) +endif() +if(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD") + list(APPEND FBSDKERNEL_LIBS kvm) +endif() + +if (NOT FBSDKERNEL_LIBS) message(STATUS "Skipping FreeBSDKernel plugin due to missing libfbsdvmcore") return() endif() @@ -13,7 +21,7 @@ add_lldb_library(lldbPluginProcessFreeBSDKernel PLUGIN LINK_LIBS lldbCore lldbTarget - fbsdvmcore + ${FBSDKERNEL_LIBS} LINK_COMPONENTS Support ) diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp b/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp index 327e25acd589..339d33d25110 100644 --- a/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp +++ b/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp @@ -10,42 +10,91 @@ #include "lldb/Core/PluginManager.h" #include "lldb/Target/DynamicLoader.h" +#include "Plugins/DynamicLoader/Static/DynamicLoaderStatic.h" #include "ProcessFreeBSDKernel.h" #include "ThreadFreeBSDKernel.h" -#include "Plugins/DynamicLoader/Static/DynamicLoaderStatic.h" +#if LLDB_ENABLE_FBSDVMCORE #include +#endif +#if defined(__FreeBSD__) +#include +#endif using namespace lldb; using namespace lldb_private; LLDB_PLUGIN_DEFINE(ProcessFreeBSDKernel) -ProcessFreeBSDKernel::ProcessFreeBSDKernel(lldb::TargetSP target_sp, - ListenerSP listener_sp, - const FileSpec &core_file, void *fvc) - : PostMortemProcess(target_sp, listener_sp), m_fvc(fvc) {} +namespace { -ProcessFreeBSDKernel::~ProcessFreeBSDKernel() { - if (m_fvc) - fvc_close(static_cast(m_fvc)); -} +#if LLDB_ENABLE_FBSDVMCORE +class ProcessFreeBSDKernelFVC : public ProcessFreeBSDKernel { +public: + ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp, lldb::ListenerSP listener, + fvc_t *fvc); + + ~ProcessFreeBSDKernelFVC(); + + size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size, + lldb_private::Status &error) override; + +private: + fvc_t *m_fvc; + + const char *GetError(); +}; +#endif // LLDB_ENABLE_FBSDVMCORE + +#if defined(__FreeBSD__) +class ProcessFreeBSDKernelKVM : public ProcessFreeBSDKernel { +public: + ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp, lldb::ListenerSP listener, + kvm_t *fvc); + + ~ProcessFreeBSDKernelKVM(); + + size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size, + lldb_private::Status &error) override; + +private: + kvm_t *m_kvm; + + const char *GetError(); +}; +#endif // defined(__FreeBSD__) + +} // namespace + +ProcessFreeBSDKernel::ProcessFreeBSDKernel(lldb::TargetSP target_sp, + ListenerSP listener_sp) + : PostMortemProcess(target_sp, listener_sp) {} lldb::ProcessSP ProcessFreeBSDKernel::CreateInstance(lldb::TargetSP target_sp, ListenerSP listener_sp, const FileSpec *crash_file, bool can_connect) { - lldb::ProcessSP process_sp; ModuleSP executable = target_sp->GetExecutableModule(); if (crash_file && !can_connect && executable) { - fvc_t *fvc = fvc_open( - executable->GetFileSpec().GetPath().c_str(), - crash_file->GetPath().c_str(), nullptr, nullptr, nullptr); +#if LLDB_ENABLE_FBSDVMCORE + fvc_t *fvc = + fvc_open(executable->GetFileSpec().GetPath().c_str(), + crash_file->GetPath().c_str(), nullptr, nullptr, nullptr); if (fvc) - process_sp = std::make_shared( - target_sp, listener_sp, *crash_file, fvc); + return std::make_shared(target_sp, listener_sp, + fvc); +#endif + +#if defined(__FreeBSD__) + kvm_t *kvm = + kvm_open2(executable->GetFileSpec().GetPath().c_str(), + crash_file->GetPath().c_str(), O_RDONLY, nullptr, nullptr); + if (kvm) + return std::make_shared(target_sp, listener_sp, + kvm); +#endif } - return process_sp; + return nullptr; } void ProcessFreeBSDKernel::Initialize() { @@ -107,20 +156,63 @@ Status ProcessFreeBSDKernel::DoLoadCore() { return Status(); } -size_t ProcessFreeBSDKernel::DoReadMemory(lldb::addr_t addr, void *buf, - size_t size, Status &error) { - ssize_t rd = fvc_read(static_cast(m_fvc), addr, buf, size); - if (rd < 0 || static_cast(rd) != size) { - error.SetErrorStringWithFormat("Reading memory failed: %s", - fvc_geterr(static_cast(m_fvc))); - return rd > 0 ? rd : 0; - } - return rd; -} - DynamicLoader *ProcessFreeBSDKernel::GetDynamicLoader() { if (m_dyld_up.get() == nullptr) m_dyld_up.reset(DynamicLoader::FindPlugin( this, DynamicLoaderStatic::GetPluginNameStatic())); return m_dyld_up.get(); } + +#if LLDB_ENABLE_FBSDVMCORE + +ProcessFreeBSDKernelFVC::ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp, + ListenerSP listener_sp, + fvc_t *fvc) + : ProcessFreeBSDKernel(target_sp, listener_sp), m_fvc(fvc) {} + +ProcessFreeBSDKernelFVC::~ProcessFreeBSDKernelFVC() { + if (m_fvc) + fvc_close(m_fvc); +} + +size_t ProcessFreeBSDKernelFVC::DoReadMemory(lldb::addr_t addr, void *buf, + size_t size, Status &error) { + ssize_t rd = 0; + rd = fvc_read(m_fvc, addr, buf, size); + if (rd < 0 || static_cast(rd) != size) { + error.SetErrorStringWithFormat("Reading memory failed: %s", GetError()); + return rd > 0 ? rd : 0; + } + return rd; +} + +const char *ProcessFreeBSDKernelFVC::GetError() { return fvc_geterr(m_fvc); } + +#endif // LLDB_ENABLE_FBSDVMCORE + +#if defined(__FreeBSD__) + +ProcessFreeBSDKernelKVM::ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp, + ListenerSP listener_sp, + kvm_t *fvc) + : ProcessFreeBSDKernel(target_sp, listener_sp), m_kvm(fvc) {} + +ProcessFreeBSDKernelKVM::~ProcessFreeBSDKernelKVM() { + if (m_kvm) + kvm_close(m_kvm); +} + +size_t ProcessFreeBSDKernelKVM::DoReadMemory(lldb::addr_t addr, void *buf, + size_t size, Status &error) { + ssize_t rd = 0; + rd = kvm_read2(m_kvm, addr, buf, size); + if (rd < 0 || static_cast(rd) != size) { + error.SetErrorStringWithFormat("Reading memory failed: %s", GetError()); + return rd > 0 ? rd : 0; + } + return rd; +} + +const char *ProcessFreeBSDKernelKVM::GetError() { return kvm_geterr(m_kvm); } + +#endif // defined(__FreeBSD__) diff --git a/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.h b/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.h index cd10728463b5..558eec5403db 100644 --- a/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.h +++ b/lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.h @@ -13,10 +13,7 @@ class ProcessFreeBSDKernel : public lldb_private::PostMortemProcess { public: - ProcessFreeBSDKernel(lldb::TargetSP target_sp, lldb::ListenerSP listener, - const lldb_private::FileSpec &core_file, void *fvc); - - ~ProcessFreeBSDKernel() override; + ProcessFreeBSDKernel(lldb::TargetSP target_sp, lldb::ListenerSP listener); static lldb::ProcessSP CreateInstance(lldb::TargetSP target_sp, lldb::ListenerSP listener, @@ -44,17 +41,11 @@ public: lldb_private::Status DoLoadCore() override; - size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size, - lldb_private::Status &error) override; - lldb_private::DynamicLoader *GetDynamicLoader() override; protected: bool DoUpdateThreadList(lldb_private::ThreadList &old_thread_list, lldb_private::ThreadList &new_thread_list) override; - -private: - void *m_fvc; }; #endif // LLDB_SOURCE_PLUGINS_PROCESS_FREEBSDKERNEL_PROCESSFREEBSDKERNEL_H diff --git a/lldb/test/API/functionalities/postmortem/FreeBSDKernel/TestFreeBSDKernelLive.py b/lldb/test/API/functionalities/postmortem/FreeBSDKernel/TestFreeBSDKernelLive.py new file mode 100644 index 000000000000..98c87461a608 --- /dev/null +++ b/lldb/test/API/functionalities/postmortem/FreeBSDKernel/TestFreeBSDKernelLive.py @@ -0,0 +1,44 @@ +import os +import struct +import subprocess + +import lldb +from lldbsuite.test.decorators import * +from lldbsuite.test.lldbtest import * +from lldbsuite.test import lldbutil + + +class FreeBSDKernelVMCoreTestCase(TestBase): + NO_DEBUG_INFO_TESTCASE = True + + mydir = TestBase.compute_mydir(__file__) + + def test_mem(self): + kernel_exec = "/boot/kernel/kernel" + mem_device = "/dev/mem" + + if not os.access(kernel_exec, os.R_OK): + self.skipTest("Kernel @ %s is not readable" % (kernel_exec,)) + if not os.access(mem_device, os.R_OK): + self.skipTest("Memory @ %s is not readable" % (mem_device,)) + + target = self.dbg.CreateTarget(kernel_exec) + process = target.LoadCore(mem_device) + hz_value = int(subprocess.check_output(["sysctl", "-n", "kern.hz"])) + + self.assertTrue(process, PROCESS_IS_VALID) + self.assertEqual(process.GetNumThreads(), 1) + self.assertEqual(process.GetProcessID(), 0) + + # test memory reading + self.expect("expr -- *(int *) &hz", + substrs=["(int) $0 = %d" % hz_value]) + + main_mod = target.GetModuleAtIndex(0) + hz_addr = (main_mod.FindSymbols("hz")[0].symbol.addr + .GetLoadAddress(target)) + error = lldb.SBError() + self.assertEqual(process.ReadMemory(hz_addr, 4, error), + struct.pack("