//===-- ProcessFreeBSDKernel.cpp ------------------------------------------===//
//
// 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 "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Target/DynamicLoader.h"
#include "Plugins/DynamicLoader/FreeBSD-Kernel/DynamicLoaderFreeBSDKernel.h"
#include "ProcessFreeBSDKernel.h"
#include "ThreadFreeBSDKernel.h"
#if LLDB_ENABLE_FBSDVMCORE
#include <fvc.h>
#endif
#if defined(__FreeBSD__)
#include <kvm.h>
#endif
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(ProcessFreeBSDKernel)
namespace {
#if LLDB_ENABLE_FBSDVMCORE
class ProcessFreeBSDKernelFVC : public ProcessFreeBSDKernel {
public:
ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp, lldb::ListenerSP listener,
fvc_t *fvc, const FileSpec &core_file);
~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, const FileSpec &core_file);
~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,
const FileSpec &core_file)
: PostMortemProcess(target_sp, listener_sp, core_file) {}
lldb::ProcessSP ProcessFreeBSDKernel::CreateInstance(lldb::TargetSP target_sp,
ListenerSP listener_sp,
const FileSpec *crash_file,
bool can_connect) {
ModuleSP executable = target_sp->GetExecutableModule();
if (crash_file && !can_connect && executable) {
#if LLDB_ENABLE_FBSDVMCORE
fvc_t *fvc =
fvc_open(executable->GetFileSpec().GetPath().c_str(),
crash_file->GetPath().c_str(), nullptr, nullptr, nullptr);
if (fvc)
return std::make_shared<ProcessFreeBSDKernelFVC>(target_sp, listener_sp,
fvc, *crash_file);
#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<ProcessFreeBSDKernelKVM>(target_sp, listener_sp,
kvm, *crash_file);
#endif
}
return nullptr;
}
void ProcessFreeBSDKernel::Initialize() {
static llvm::once_flag g_once_flag;
llvm::call_once(g_once_flag, []() {
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(), CreateInstance);
});
}
void ProcessFreeBSDKernel::Terminate() {
PluginManager::UnregisterPlugin(ProcessFreeBSDKernel::CreateInstance);
}
Status ProcessFreeBSDKernel::DoDestroy() { return Status(); }
bool ProcessFreeBSDKernel::CanDebug(lldb::TargetSP target_sp,
bool plugin_specified_by_name) {
return true;
}
void ProcessFreeBSDKernel::RefreshStateAfterStop() {}
bool ProcessFreeBSDKernel::DoUpdateThreadList(ThreadList &old_thread_list,
ThreadList &new_thread_list) {
if (old_thread_list.GetSize(false) == 0) {
// Make up the thread the first time this is called so we can set our one
// and only core thread state up.
// We cannot construct a thread without a register context as that crashes
// LLDB but we can construct a process without threads to provide minimal
// memory reading support.
switch (GetTarget().GetArchitecture().GetMachine()) {
case llvm::Triple::aarch64:
case llvm::Triple::x86:
case llvm::Triple::x86_64:
break;
default:
return false;
}
Status error;
// struct field offsets are written as symbols so that we don't have
// to figure them out ourselves
int32_t offset_p_list = ReadSignedIntegerFromMemory(
FindSymbol("proc_off_p_list"), 4, -1, error);
int32_t offset_p_pid =
ReadSignedIntegerFromMemory(FindSymbol("proc_off_p_pid"), 4, -1, error);
int32_t offset_p_threads = ReadSignedIntegerFromMemory(
FindSymbol("proc_off_p_threads"), 4, -1, error);
int32_t offset_p_comm = ReadSignedIntegerFromMemory(
FindSymbol("proc_off_p_comm"), 4, -1, error);
int32_t offset_td_tid = ReadSignedIntegerFromMemory(
FindSymbol("thread_off_td_tid"), 4, -1, error);
int32_t offset_td_plist = ReadSignedIntegerFromMemory(
FindSymbol("thread_off_td_plist"), 4, -1, error);
int32_t offset_td_pcb = ReadSignedIntegerFromMemory(
FindSymbol("thread_off_td_pcb"), 4, -1, error);
int32_t offset_td_oncpu = ReadSignedIntegerFromMemory(
FindSymbol("thread_off_td_oncpu"), 4, -1, error);
int32_t offset_td_name = ReadSignedIntegerFromMemory(
FindSymbol("thread_off_td_name"), 4, -1, error);
// fail if we were not able to read any of the offsets
if (offset_p_list == -1 || offset_p_pid == -1 || offset_p_threads == -1 ||
offset_p_comm == -1 || offset_td_tid == -1 || offset_td_plist == -1 ||
offset_td_pcb == -1 || offset_td_oncpu == -1 || offset_td_name == -1)
return false;
// dumptid contains the thread-id of the crashing thread
// dumppcb contains its PCB
int32_t dumptid =
ReadSignedIntegerFromMemory(FindSymbol("dumptid"), 4, -1, error);
lldb::addr_t dumppcb = FindSymbol("dumppcb");
// stoppcbs is an array of PCBs on all CPUs
// each element is of size pcb_size
int32_t pcbsize =
ReadSignedIntegerFromMemory(FindSymbol("pcb_size"), 4, -1, error);
lldb::addr_t stoppcbs = FindSymbol("stoppcbs");
// from FreeBSD sys/param.h
constexpr size_t fbsd_maxcomlen = 19;
// iterate through a linked list of all processes
// allproc is a pointer to the first list element, p_list field
// (found at offset_p_list) specifies the next element
for (lldb::addr_t proc =
ReadPointerFromMemory(FindSymbol("allproc"), error);
proc != 0 && proc != LLDB_INVALID_ADDRESS;
proc = ReadPointerFromMemory(proc + offset_p_list, error)) {
int32_t pid =
ReadSignedIntegerFromMemory(proc + offset_p_pid, 4, -1, error);
// process' command-line string
char comm[fbsd_maxcomlen + 1];
ReadCStringFromMemory(proc + offset_p_comm, comm, sizeof(comm), error);
// iterate through a linked list of all process' threads
// the initial thread is found in process' p_threads, subsequent
// elements are linked via td_plist field
for (lldb::addr_t td =
ReadPointerFromMemory(proc + offset_p_threads, error);
td != 0; td = ReadPointerFromMemory(td + offset_td_plist, error)) {
int32_t tid =
ReadSignedIntegerFromMemory(td + offset_td_tid, 4, -1, error);
lldb::addr_t pcb_addr =
ReadPointerFromMemory(td + offset_td_pcb, error);
// whether process was on CPU (-1 if not, otherwise CPU number)
int32_t oncpu =
ReadSignedIntegerFromMemory(td + offset_td_oncpu, 4, -2, error);
// thread name
char thread_name[fbsd_maxcomlen + 1];
ReadCStringFromMemory(td + offset_td_name, thread_name,
sizeof(thread_name), error);
// if we failed to read TID, ignore this thread
if (tid == -1)
continue;
std::string thread_desc = llvm::formatv("(pid {0}) {1}", pid, comm);
if (*thread_name && strcmp(thread_name, comm)) {
thread_desc += '/';
thread_desc += thread_name;
}
// roughly:
// 1. if the thread crashed, its PCB is going to be at "dumppcb"
// 2. if the thread was on CPU, its PCB is going to be on the CPU
// 3. otherwise, its PCB is in the thread struct
if (tid == dumptid) {
// NB: dumppcb can be LLDB_INVALID_ADDRESS if reading it failed
pcb_addr = dumppcb;
thread_desc += " (crashed)";
} else if (oncpu != -1) {
// if we managed to read stoppcbs and pcb_size, use them to find
// the correct PCB
if (stoppcbs != LLDB_INVALID_ADDRESS && pcbsize > 0)
pcb_addr = stoppcbs + oncpu * pcbsize;
else
pcb_addr = LLDB_INVALID_ADDRESS;
thread_desc += llvm::formatv(" (on CPU {0})", oncpu);
}
ThreadSP thread_sp{
new ThreadFreeBSDKernel(*this, tid, pcb_addr, thread_desc)};
new_thread_list.AddThread(thread_sp);
}
}
} else {
const uint32_t num_threads = old_thread_list.GetSize(false);
for (uint32_t i = 0; i < num_threads; ++i)
new_thread_list.AddThread(old_thread_list.GetThreadAtIndex(i, false));
}
return new_thread_list.GetSize(false) > 0;
}
Status ProcessFreeBSDKernel::DoLoadCore() {
// The core is already loaded by CreateInstance().
return Status();
}
DynamicLoader *ProcessFreeBSDKernel::GetDynamicLoader() {
if (m_dyld_up.get() == nullptr)
m_dyld_up.reset(DynamicLoader::FindPlugin(
this, DynamicLoaderFreeBSDKernel::GetPluginNameStatic()));
return m_dyld_up.get();
}
lldb::addr_t ProcessFreeBSDKernel::FindSymbol(const char *name) {
ModuleSP mod_sp = GetTarget().GetExecutableModule();
const Symbol *sym = mod_sp->FindFirstSymbolWithNameAndType(ConstString(name));
return sym ? sym->GetLoadAddress(&GetTarget()) : LLDB_INVALID_ADDRESS;
}
#if LLDB_ENABLE_FBSDVMCORE
ProcessFreeBSDKernelFVC::ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp,
ListenerSP listener_sp,
fvc_t *fvc,
const FileSpec &core_file)
: ProcessFreeBSDKernel(target_sp, listener_sp, crash_file), 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<size_t>(rd) != size) {
error = Status::FromErrorStringWithFormat("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,
const FileSpec &core_file)
: ProcessFreeBSDKernel(target_sp, listener_sp, core_file), 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<size_t>(rd) != size) {
error = Status::FromErrorStringWithFormat("Reading memory failed: %s",
GetError());
return rd > 0 ? rd : 0;
}
return rd;
}
const char *ProcessFreeBSDKernelKVM::GetError() { return kvm_geterr(m_kvm); }
#endif // defined(__FreeBSD__)
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