gecko-dev/xpcom/threads/ThreadStackHelper.cpp

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C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ThreadStackHelper.h"
#include "MainThreadUtils.h"
#include "nsJSPrincipals.h"
#include "nsScriptSecurityManager.h"
#include "jsfriendapi.h"
#include "prprf.h"
#ifdef MOZ_THREADSTACKHELPER_NATIVE
#include "shared-libraries.h"
#endif
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/Move.h"
#include "mozilla/Scoped.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/MemoryChecking.h"
#ifdef MOZ_THREADSTACKHELPER_NATIVE
#include "google_breakpad/processor/call_stack.h"
#include "google_breakpad/processor/basic_source_line_resolver.h"
#include "google_breakpad/processor/stack_frame_cpu.h"
#include "processor/basic_code_module.h"
#include "processor/basic_code_modules.h"
#endif
#if defined(MOZ_THREADSTACKHELPER_X86)
#include "processor/stackwalker_x86.h"
#elif defined(MOZ_THREADSTACKHELPER_X64)
#include "processor/stackwalker_amd64.h"
#elif defined(MOZ_THREADSTACKHELPER_ARM)
#include "processor/stackwalker_arm.h"
#endif
#if defined(MOZ_VALGRIND)
# include <valgrind/valgrind.h>
#endif
#include <string.h>
#include <vector>
#include <cstdlib>
#ifdef XP_LINUX
#ifdef ANDROID
// Android NDK doesn't contain ucontext.h; use Breakpad's copy.
# include "common/android/include/sys/ucontext.h"
#else
# include <ucontext.h>
#endif
#include <unistd.h>
#include <sys/syscall.h>
#endif
#if defined(XP_LINUX) || defined(XP_MACOSX)
#include <pthread.h>
#endif
#ifdef ANDROID
#ifndef SYS_gettid
#define SYS_gettid __NR_gettid
#endif
#if defined(__arm__) && !defined(__NR_rt_tgsigqueueinfo)
// Some NDKs don't define this constant even though the kernel supports it.
#define __NR_rt_tgsigqueueinfo (__NR_SYSCALL_BASE+363)
#endif
#ifndef SYS_rt_tgsigqueueinfo
#define SYS_rt_tgsigqueueinfo __NR_rt_tgsigqueueinfo
#endif
#endif
#ifdef MOZ_THREADSTACKHELPER_NATIVE
#if defined(MOZ_THREADSTACKHELPER_X86) || \
defined(MOZ_THREADSTACKHELPER_X64) || \
defined(MOZ_THREADSTACKHELPER_ARM)
// On these architectures, the stack grows downwards (toward lower addresses).
#define MOZ_THREADSTACKHELPER_STACK_GROWS_DOWN
#else
#error "Unsupported architecture"
#endif
#endif // MOZ_THREADSTACKHELPER_NATIVE
namespace mozilla {
void
ThreadStackHelper::Startup()
{
#if defined(XP_LINUX)
MOZ_ASSERT(NS_IsMainThread());
if (!sInitialized) {
// TODO: centralize signal number allocation
sFillStackSignum = SIGRTMIN + 4;
if (sFillStackSignum > SIGRTMAX) {
// Leave uninitialized
MOZ_ASSERT(false);
return;
}
struct sigaction sigact = {};
sigact.sa_sigaction = FillStackHandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = SA_SIGINFO | SA_RESTART;
MOZ_ALWAYS_TRUE(!::sigaction(sFillStackSignum, &sigact, nullptr));
}
sInitialized++;
#endif
}
void
ThreadStackHelper::Shutdown()
{
#if defined(XP_LINUX)
MOZ_ASSERT(NS_IsMainThread());
if (sInitialized == 1) {
struct sigaction sigact = {};
sigact.sa_handler = SIG_DFL;
MOZ_ALWAYS_TRUE(!::sigaction(sFillStackSignum, &sigact, nullptr));
}
sInitialized--;
#endif
}
ThreadStackHelper::ThreadStackHelper()
: mStackToFill(nullptr)
#ifdef MOZ_THREADSTACKHELPER_PSEUDO
, mPseudoStack(mozilla_get_pseudo_stack())
#ifdef MOZ_THREADSTACKHELPER_NATIVE
, mContextToFill(nullptr)
#endif
, mMaxStackSize(Stack::sMaxInlineStorage)
, mMaxBufferSize(0)
#endif
{
#if defined(XP_LINUX)
MOZ_ALWAYS_TRUE(!::sem_init(&mSem, 0, 0));
mThreadID = ::syscall(SYS_gettid);
#elif defined(XP_WIN)
mInitialized = !!::DuplicateHandle(
::GetCurrentProcess(), ::GetCurrentThread(),
::GetCurrentProcess(), &mThreadID,
THREAD_SUSPEND_RESUME
#ifdef MOZ_THREADSTACKHELPER_NATIVE
| THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION
#endif
, FALSE, 0);
MOZ_ASSERT(mInitialized);
#elif defined(XP_MACOSX)
mThreadID = mach_thread_self();
#endif
#ifdef MOZ_THREADSTACKHELPER_NATIVE
GetThreadStackBase();
#endif
}
ThreadStackHelper::~ThreadStackHelper()
{
#if defined(XP_LINUX)
MOZ_ALWAYS_TRUE(!::sem_destroy(&mSem));
#elif defined(XP_WIN)
if (mInitialized) {
MOZ_ALWAYS_TRUE(!!::CloseHandle(mThreadID));
}
#endif
}
#ifdef MOZ_THREADSTACKHELPER_NATIVE
void ThreadStackHelper::GetThreadStackBase()
{
mThreadStackBase = 0;
#if defined(XP_LINUX)
void* stackAddr;
size_t stackSize;
::pthread_t pthr = ::pthread_self();
::pthread_attr_t pthr_attr;
NS_ENSURE_TRUE_VOID(!::pthread_getattr_np(pthr, &pthr_attr));
if (!::pthread_attr_getstack(&pthr_attr, &stackAddr, &stackSize)) {
#ifdef MOZ_THREADSTACKHELPER_STACK_GROWS_DOWN
mThreadStackBase = intptr_t(stackAddr) + stackSize;
#else
mThreadStackBase = intptr_t(stackAddr);
#endif
}
MOZ_ALWAYS_TRUE(!::pthread_attr_destroy(&pthr_attr));
#elif defined(XP_WIN)
::MEMORY_BASIC_INFORMATION meminfo = {};
NS_ENSURE_TRUE_VOID(::VirtualQuery(&meminfo, &meminfo, sizeof(meminfo)));
#ifdef MOZ_THREADSTACKHELPER_STACK_GROWS_DOWN
mThreadStackBase = intptr_t(meminfo.BaseAddress) + meminfo.RegionSize;
#else
mThreadStackBase = intptr_t(meminfo.AllocationBase);
#endif
#elif defined(XP_MACOSX)
::pthread_t pthr = ::pthread_self();
mThreadStackBase = intptr_t(::pthread_get_stackaddr_np(pthr));
#else
#error "Unsupported platform"
#endif // platform
}
#endif // MOZ_THREADSTACKHELPER_NATIVE
namespace {
template<typename T>
class ScopedSetPtr
{
private:
T*& mPtr;
public:
ScopedSetPtr(T*& p, T* val) : mPtr(p) { mPtr = val; }
~ScopedSetPtr() { mPtr = nullptr; }
};
}
void
ThreadStackHelper::GetStack(Stack& aStack)
{
// Always run PrepareStackBuffer first to clear aStack
if (!PrepareStackBuffer(aStack)) {
// Skip and return empty aStack
return;
}
ScopedSetPtr<Stack> stackPtr(mStackToFill, &aStack);
#if defined(XP_LINUX)
if (!sInitialized) {
MOZ_ASSERT(false);
return;
}
siginfo_t uinfo = {};
uinfo.si_signo = sFillStackSignum;
uinfo.si_code = SI_QUEUE;
uinfo.si_pid = getpid();
uinfo.si_uid = getuid();
uinfo.si_value.sival_ptr = this;
if (::syscall(SYS_rt_tgsigqueueinfo, uinfo.si_pid,
mThreadID, sFillStackSignum, &uinfo)) {
// rt_tgsigqueueinfo was added in Linux 2.6.31.
// Could have failed because the syscall did not exist.
return;
}
MOZ_ALWAYS_TRUE(!::sem_wait(&mSem));
#elif defined(XP_WIN)
if (!mInitialized) {
MOZ_ASSERT(false);
return;
}
if (::SuspendThread(mThreadID) == DWORD(-1)) {
MOZ_ASSERT(false);
return;
}
FillStackBuffer();
FillThreadContext();
MOZ_ALWAYS_TRUE(::ResumeThread(mThreadID) != DWORD(-1));
#elif defined(XP_MACOSX)
# if defined(MOZ_VALGRIND) && defined(RUNNING_ON_VALGRIND)
if (RUNNING_ON_VALGRIND) {
/* thread_suspend and thread_resume sometimes hang runs on Valgrind,
for unknown reasons. So, just avoid them. See bug 1100911. */
return;
}
# endif
if (::thread_suspend(mThreadID) != KERN_SUCCESS) {
MOZ_ASSERT(false);
return;
}
FillStackBuffer();
FillThreadContext();
MOZ_ALWAYS_TRUE(::thread_resume(mThreadID) == KERN_SUCCESS);
#endif
}
#ifdef MOZ_THREADSTACKHELPER_NATIVE
class ThreadStackHelper::CodeModulesProvider
: public google_breakpad::CodeModules
{
private:
typedef google_breakpad::CodeModule CodeModule;
typedef google_breakpad::BasicCodeModule BasicCodeModule;
const SharedLibraryInfo mLibs;
mutable ScopedDeletePtr<BasicCodeModule> mModule;
public:
CodeModulesProvider() : mLibs(SharedLibraryInfo::GetInfoForSelf()) {}
virtual ~CodeModulesProvider() {}
virtual unsigned int module_count() const
{
return mLibs.GetSize();
}
virtual const CodeModule* GetModuleForAddress(uint64_t aAddress) const
{
MOZ_CRASH("Not implemented");
}
virtual const CodeModule* GetMainModule() const
{
return nullptr;
}
virtual const CodeModule* GetModuleAtSequence(unsigned int aSequence) const
{
MOZ_CRASH("Not implemented");
}
virtual const CodeModule* GetModuleAtIndex(unsigned int aIndex) const
{
const SharedLibrary& lib = mLibs.GetEntry(aIndex);
mModule = new BasicCodeModule(lib.GetStart(), lib.GetEnd() - lib.GetStart(),
lib.GetName(), lib.GetBreakpadId(),
lib.GetName(), lib.GetBreakpadId(), "");
// Keep mModule valid until the next GetModuleAtIndex call.
return mModule;
}
virtual const CodeModules* Copy() const
{
MOZ_CRASH("Not implemented");
}
};
class ThreadStackHelper::ThreadContext final
: public google_breakpad::MemoryRegion
{
public:
#if defined(MOZ_THREADSTACKHELPER_X86)
typedef MDRawContextX86 Context;
#elif defined(MOZ_THREADSTACKHELPER_X64)
typedef MDRawContextAMD64 Context;
#elif defined(MOZ_THREADSTACKHELPER_ARM)
typedef MDRawContextARM Context;
#endif
// Limit copied stack to 4kB
static const size_t kMaxStackSize = 0x1000;
// Limit unwound stack to 32 frames
static const unsigned int kMaxStackFrames = 32;
// Whether this structure contains valid data
bool mValid;
// Processor context
Context mContext;
// Stack area
UniquePtr<uint8_t[]> mStack;
// Start of stack area
uintptr_t mStackBase;
// Size of stack area
size_t mStackSize;
// End of stack area
const void* mStackEnd;
ThreadContext()
: mValid(false)
, mStackBase(0)
, mStackSize(0)
, mStackEnd(nullptr) {}
virtual ~ThreadContext() {}
virtual uint64_t GetBase() const { return uint64_t(mStackBase); }
virtual uint32_t GetSize() const { return mStackSize; }
virtual bool GetMemoryAtAddress(uint64_t aAddress, uint8_t* aValue) const
{
return GetMemoryAtAddressInternal(aAddress, aValue);
}
virtual bool GetMemoryAtAddress(uint64_t aAddress, uint16_t* aValue) const
{
return GetMemoryAtAddressInternal(aAddress, aValue);
}
virtual bool GetMemoryAtAddress(uint64_t aAddress, uint32_t* aValue) const
{
return GetMemoryAtAddressInternal(aAddress, aValue);
}
virtual bool GetMemoryAtAddress(uint64_t aAddress, uint64_t* aValue) const
{
return GetMemoryAtAddressInternal(aAddress, aValue);
}
private:
template<typename T>
bool GetMemoryAtAddressInternal(uint64_t aAddress, T* aValue) const
{
const intptr_t offset = intptr_t(aAddress) - intptr_t(GetBase());
if (offset < 0 || uintptr_t(offset) > (GetSize() - sizeof(T))) {
return false;
}
*aValue = *reinterpret_cast<const T*>(&mStack[offset]);
return true;
}
};
#endif // MOZ_THREADSTACKHELPER_NATIVE
void
ThreadStackHelper::GetNativeStack(Stack& aStack)
{
#ifdef MOZ_THREADSTACKHELPER_NATIVE
ThreadContext context;
context.mStack = MakeUnique<uint8_t[]>(ThreadContext::kMaxStackSize);
ScopedSetPtr<ThreadContext> contextPtr(mContextToFill, &context);
// Get pseudostack first and fill the thread context.
GetStack(aStack);
NS_ENSURE_TRUE_VOID(context.mValid);
CodeModulesProvider modulesProvider;
google_breakpad::BasicCodeModules modules(&modulesProvider);
google_breakpad::BasicSourceLineResolver resolver;
google_breakpad::StackFrameSymbolizer symbolizer(nullptr, &resolver);
#if defined(MOZ_THREADSTACKHELPER_X86)
google_breakpad::StackwalkerX86 stackWalker(
nullptr, &context.mContext, &context, &modules, &symbolizer);
#elif defined(MOZ_THREADSTACKHELPER_X64)
google_breakpad::StackwalkerAMD64 stackWalker(
nullptr, &context.mContext, &context, &modules, &symbolizer);
#elif defined(MOZ_THREADSTACKHELPER_ARM)
google_breakpad::StackwalkerARM stackWalker(
nullptr, &context.mContext, -1, &context, &modules, &symbolizer);
#else
#error "Unsupported architecture"
#endif
google_breakpad::CallStack callStack;
std::vector<const google_breakpad::CodeModule*> modules_without_symbols;
google_breakpad::Stackwalker::set_max_frames(ThreadContext::kMaxStackFrames);
google_breakpad::Stackwalker::
set_max_frames_scanned(ThreadContext::kMaxStackFrames);
NS_ENSURE_TRUE_VOID(stackWalker.Walk(&callStack, &modules_without_symbols));
const std::vector<google_breakpad::StackFrame*>& frames(*callStack.frames());
for (intptr_t i = frames.size() - 1; i >= 0; i--) {
const google_breakpad::StackFrame& frame = *frames[i];
if (!frame.module) {
continue;
}
const string& module = frame.module->code_file();
#if defined(XP_LINUX) || defined(XP_MACOSX)
const char PATH_SEP = '/';
#elif defined(XP_WIN)
const char PATH_SEP = '\\';
#endif
const char* const module_basename = strrchr(module.c_str(), PATH_SEP);
const char* const module_name = module_basename ?
module_basename + 1 : module.c_str();
char buffer[0x100];
size_t len = 0;
if (!frame.function_name.empty()) {
len = PR_snprintf(buffer, sizeof(buffer), "%s:%s",
module_name, frame.function_name.c_str());
} else {
len = PR_snprintf(buffer, sizeof(buffer), "%s:0x%p",
module_name, (intptr_t)
(frame.instruction - frame.module->base_address()));
}
if (len) {
aStack.AppendViaBuffer(buffer, len);
}
}
#endif // MOZ_THREADSTACKHELPER_NATIVE
}
#ifdef XP_LINUX
int ThreadStackHelper::sInitialized;
int ThreadStackHelper::sFillStackSignum;
void
ThreadStackHelper::FillStackHandler(int aSignal, siginfo_t* aInfo,
void* aContext)
{
ThreadStackHelper* const helper =
reinterpret_cast<ThreadStackHelper*>(aInfo->si_value.sival_ptr);
helper->FillStackBuffer();
helper->FillThreadContext(aContext);
::sem_post(&helper->mSem);
}
#endif // XP_LINUX
bool
ThreadStackHelper::PrepareStackBuffer(Stack& aStack)
{
// Return false to skip getting the stack and return an empty stack
aStack.clear();
#ifdef MOZ_THREADSTACKHELPER_PSEUDO
/* Normally, provided the profiler is enabled, it would be an error if we
don't have a pseudostack here (the thread probably forgot to call
profiler_register_thread). However, on B2G, profiling secondary threads
may be disabled despite profiler being enabled. This is by-design and
is not an error. */
#ifdef MOZ_WIDGET_GONK
if (!mPseudoStack) {
return false;
}
#endif
MOZ_ASSERT(mPseudoStack);
if (!aStack.reserve(mMaxStackSize) ||
!aStack.reserve(aStack.capacity()) || // reserve up to the capacity
!aStack.EnsureBufferCapacity(mMaxBufferSize)) {
return false;
}
return true;
#else
return false;
#endif
}
#ifdef MOZ_THREADSTACKHELPER_PSEUDO
namespace {
bool
IsChromeJSScript(JSScript* aScript)
{
// May be called from another thread or inside a signal handler.
// We assume querying the script is safe but we must not manipulate it.
nsIScriptSecurityManager* const secman =
nsScriptSecurityManager::GetScriptSecurityManager();
NS_ENSURE_TRUE(secman, false);
JSPrincipals* const principals = JS_GetScriptPrincipals(aScript);
return secman->IsSystemPrincipal(nsJSPrincipals::get(principals));
}
// Get the full path after the URI scheme, if the URI matches the scheme.
// For example, GetFullPathForScheme("a://b/c/d/e", "a://") returns "b/c/d/e".
template <size_t LEN>
const char*
GetFullPathForScheme(const char* filename, const char (&scheme)[LEN]) {
// Account for the null terminator included in LEN.
if (!strncmp(filename, scheme, LEN - 1)) {
return filename + LEN - 1;
}
return nullptr;
}
// Get the full path after a URI component, if the URI contains the component.
// For example, GetPathAfterComponent("a://b/c/d/e", "/c/") returns "d/e".
template <size_t LEN>
const char*
GetPathAfterComponent(const char* filename, const char (&component)[LEN]) {
const char* found = nullptr;
const char* next = strstr(filename, component);
while (next) {
// Move 'found' to end of the component, after the separator '/'.
// 'LEN - 1' accounts for the null terminator included in LEN,
found = next + LEN - 1;
// Resume searching before the separator '/'.
next = strstr(found - 1, component);
}
return found;
}
} // namespace
const char*
ThreadStackHelper::AppendJSEntry(const volatile StackEntry* aEntry,
intptr_t& aAvailableBufferSize,
const char* aPrevLabel)
{
// May be called from another thread or inside a signal handler.
// We assume querying the script is safe but we must not manupulate it.
// Also we must not allocate any memory from heap.
MOZ_ASSERT(aEntry->isJs());
MOZ_ASSERT(aEntry->script());
const char* label;
if (IsChromeJSScript(aEntry->script())) {
const char* filename = JS_GetScriptFilename(aEntry->script());
const unsigned lineno = JS_PCToLineNumber(aEntry->script(), aEntry->pc());
MOZ_ASSERT(filename);
char buffer[128]; // Enough to fit longest js file name from the tree
// Some script names are in the form "foo -> bar -> baz".
// Here we find the origin of these redirected scripts.
const char* basename = GetPathAfterComponent(filename, " -> ");
if (basename) {
filename = basename;
}
basename = GetFullPathForScheme(filename, "chrome://");
if (!basename) {
basename = GetFullPathForScheme(filename, "resource://");
}
if (!basename) {
// If the (add-on) script is located under the {profile}/extensions
// directory, extract the path after the /extensions/ part.
basename = GetPathAfterComponent(filename, "/extensions/");
}
if (!basename) {
// Only keep the file base name for paths outside the above formats.
basename = strrchr(filename, '/');
basename = basename ? basename + 1 : filename;
// Look for Windows path separator as well.
filename = strrchr(basename, '\\');
if (filename) {
basename = filename + 1;
}
}
size_t len = PR_snprintf(buffer, sizeof(buffer), "%s:%u", basename, lineno);
if (len < sizeof(buffer)) {
if (mStackToFill->IsSameAsEntry(aPrevLabel, buffer)) {
return aPrevLabel;
}
// Keep track of the required buffer size
aAvailableBufferSize -= (len + 1);
if (aAvailableBufferSize >= 0) {
// Buffer is big enough.
return mStackToFill->InfallibleAppendViaBuffer(buffer, len);
}
// Buffer is not big enough; fall through to using static label below.
}
// snprintf failed or buffer is not big enough.
label = "(chrome script)";
} else {
label = "(content script)";
}
if (mStackToFill->IsSameAsEntry(aPrevLabel, label)) {
return aPrevLabel;
}
mStackToFill->infallibleAppend(label);
return label;
}
#endif // MOZ_THREADSTACKHELPER_PSEUDO
void
ThreadStackHelper::FillStackBuffer()
{
MOZ_ASSERT(mStackToFill->empty());
#ifdef MOZ_THREADSTACKHELPER_PSEUDO
size_t reservedSize = mStackToFill->capacity();
size_t reservedBufferSize = mStackToFill->AvailableBufferSize();
intptr_t availableBufferSize = intptr_t(reservedBufferSize);
// Go from front to back
const volatile StackEntry* entry = mPseudoStack->mStack;
const volatile StackEntry* end = entry + mPseudoStack->stackSize();
// Deduplicate identical, consecutive frames
const char* prevLabel = nullptr;
for (; reservedSize-- && entry != end; entry++) {
/* We only accept non-copy labels, including js::RunScript,
because we only want static labels in the hang stack. */
if (entry->isCopyLabel()) {
continue;
}
if (entry->isJs()) {
prevLabel = AppendJSEntry(entry, availableBufferSize, prevLabel);
continue;
}
#ifdef MOZ_THREADSTACKHELPER_NATIVE
if (mContextToFill) {
mContextToFill->mStackEnd = entry->stackAddress();
}
#endif
const char* const label = entry->label();
if (mStackToFill->IsSameAsEntry(prevLabel, label)) {
// Avoid duplicate labels to save space in the stack.
continue;
}
mStackToFill->infallibleAppend(label);
prevLabel = label;
}
// end != entry if we exited early due to not enough reserved frames.
// Expand the number of reserved frames for next time.
mMaxStackSize = mStackToFill->capacity() + (end - entry);
// availableBufferSize < 0 if we needed a larger buffer than we reserved.
// Calculate a new reserve size for next time.
if (availableBufferSize < 0) {
mMaxBufferSize = reservedBufferSize - availableBufferSize;
}
#endif
}
MOZ_ASAN_BLACKLIST void
ThreadStackHelper::FillThreadContext(void* aContext)
{
#ifdef MOZ_THREADSTACKHELPER_NATIVE
if (!mContextToFill) {
return;
}
#if defined(XP_LINUX)
const ucontext_t& context = *reinterpret_cast<ucontext_t*>(aContext);
#if defined(MOZ_THREADSTACKHELPER_X86)
mContextToFill->mContext.context_flags = MD_CONTEXT_X86_FULL;
mContextToFill->mContext.edi = context.uc_mcontext.gregs[REG_EDI];
mContextToFill->mContext.esi = context.uc_mcontext.gregs[REG_ESI];
mContextToFill->mContext.ebx = context.uc_mcontext.gregs[REG_EBX];
mContextToFill->mContext.edx = context.uc_mcontext.gregs[REG_EDX];
mContextToFill->mContext.ecx = context.uc_mcontext.gregs[REG_ECX];
mContextToFill->mContext.eax = context.uc_mcontext.gregs[REG_EAX];
mContextToFill->mContext.ebp = context.uc_mcontext.gregs[REG_EBP];
mContextToFill->mContext.eip = context.uc_mcontext.gregs[REG_EIP];
mContextToFill->mContext.eflags = context.uc_mcontext.gregs[REG_EFL];
mContextToFill->mContext.esp = context.uc_mcontext.gregs[REG_ESP];
#elif defined(MOZ_THREADSTACKHELPER_X64)
mContextToFill->mContext.context_flags = MD_CONTEXT_AMD64_FULL;
mContextToFill->mContext.eflags = uint32_t(context.uc_mcontext.gregs[REG_EFL]);
mContextToFill->mContext.rax = context.uc_mcontext.gregs[REG_RAX];
mContextToFill->mContext.rcx = context.uc_mcontext.gregs[REG_RCX];
mContextToFill->mContext.rdx = context.uc_mcontext.gregs[REG_RDX];
mContextToFill->mContext.rbx = context.uc_mcontext.gregs[REG_RBX];
mContextToFill->mContext.rsp = context.uc_mcontext.gregs[REG_RSP];
mContextToFill->mContext.rbp = context.uc_mcontext.gregs[REG_RBP];
mContextToFill->mContext.rsi = context.uc_mcontext.gregs[REG_RSI];
mContextToFill->mContext.rdi = context.uc_mcontext.gregs[REG_RDI];
memcpy(&mContextToFill->mContext.r8,
&context.uc_mcontext.gregs[REG_R8], 8 * sizeof(int64_t));
mContextToFill->mContext.rip = context.uc_mcontext.gregs[REG_RIP];
#elif defined(MOZ_THREADSTACKHELPER_ARM)
mContextToFill->mContext.context_flags = MD_CONTEXT_ARM_FULL;
memcpy(&mContextToFill->mContext.iregs[0],
&context.uc_mcontext.arm_r0, 17 * sizeof(int32_t));
#else
#error "Unsupported architecture"
#endif // architecture
#elif defined(XP_WIN)
// Breakpad context struct is based off of the Windows CONTEXT struct,
// so we assume they are the same; do some sanity checks to make sure.
static_assert(sizeof(ThreadContext::Context) == sizeof(::CONTEXT),
"Context struct mismatch");
static_assert(offsetof(ThreadContext::Context, context_flags) ==
offsetof(::CONTEXT, ContextFlags),
"Context struct mismatch");
mContextToFill->mContext.context_flags = CONTEXT_FULL;
NS_ENSURE_TRUE_VOID(::GetThreadContext(mThreadID,
reinterpret_cast<::CONTEXT*>(&mContextToFill->mContext)));
#elif defined(XP_MACOSX)
#if defined(MOZ_THREADSTACKHELPER_X86)
const thread_state_flavor_t flavor = x86_THREAD_STATE32;
x86_thread_state32_t state = {};
mach_msg_type_number_t count = x86_THREAD_STATE32_COUNT;
#elif defined(MOZ_THREADSTACKHELPER_X64)
const thread_state_flavor_t flavor = x86_THREAD_STATE64;
x86_thread_state64_t state = {};
mach_msg_type_number_t count = x86_THREAD_STATE64_COUNT;
#elif defined(MOZ_THREADSTACKHELPER_ARM)
const thread_state_flavor_t flavor = ARM_THREAD_STATE;
arm_thread_state_t state = {};
mach_msg_type_number_t count = ARM_THREAD_STATE_COUNT;
#endif
NS_ENSURE_TRUE_VOID(KERN_SUCCESS == ::thread_get_state(
mThreadID, flavor, reinterpret_cast<thread_state_t>(&state), &count));
#if __DARWIN_UNIX03
#define GET_REGISTER(s, r) ((s).__##r)
#else
#define GET_REGISTER(s, r) ((s).r)
#endif
#if defined(MOZ_THREADSTACKHELPER_X86)
mContextToFill->mContext.context_flags = MD_CONTEXT_X86_FULL;
mContextToFill->mContext.edi = GET_REGISTER(state, edi);
mContextToFill->mContext.esi = GET_REGISTER(state, esi);
mContextToFill->mContext.ebx = GET_REGISTER(state, ebx);
mContextToFill->mContext.edx = GET_REGISTER(state, edx);
mContextToFill->mContext.ecx = GET_REGISTER(state, ecx);
mContextToFill->mContext.eax = GET_REGISTER(state, eax);
mContextToFill->mContext.ebp = GET_REGISTER(state, ebp);
mContextToFill->mContext.eip = GET_REGISTER(state, eip);
mContextToFill->mContext.eflags = GET_REGISTER(state, eflags);
mContextToFill->mContext.esp = GET_REGISTER(state, esp);
#elif defined(MOZ_THREADSTACKHELPER_X64)
mContextToFill->mContext.context_flags = MD_CONTEXT_AMD64_FULL;
mContextToFill->mContext.eflags = uint32_t(GET_REGISTER(state, rflags));
mContextToFill->mContext.rax = GET_REGISTER(state, rax);
mContextToFill->mContext.rcx = GET_REGISTER(state, rcx);
mContextToFill->mContext.rdx = GET_REGISTER(state, rdx);
mContextToFill->mContext.rbx = GET_REGISTER(state, rbx);
mContextToFill->mContext.rsp = GET_REGISTER(state, rsp);
mContextToFill->mContext.rbp = GET_REGISTER(state, rbp);
mContextToFill->mContext.rsi = GET_REGISTER(state, rsi);
mContextToFill->mContext.rdi = GET_REGISTER(state, rdi);
memcpy(&mContextToFill->mContext.r8,
&GET_REGISTER(state, r8), 8 * sizeof(int64_t));
mContextToFill->mContext.rip = GET_REGISTER(state, rip);
#elif defined(MOZ_THREADSTACKHELPER_ARM)
mContextToFill->mContext.context_flags = MD_CONTEXT_ARM_FULL;
memcpy(mContextToFill->mContext.iregs,
GET_REGISTER(state, r), 17 * sizeof(int32_t));
#else
#error "Unsupported architecture"
#endif // architecture
#undef GET_REGISTER
#else
#error "Unsupported platform"
#endif // platform
intptr_t sp = 0;
#if defined(MOZ_THREADSTACKHELPER_X86)
sp = mContextToFill->mContext.esp;
#elif defined(MOZ_THREADSTACKHELPER_X64)
sp = mContextToFill->mContext.rsp;
#elif defined(MOZ_THREADSTACKHELPER_ARM)
sp = mContextToFill->mContext.iregs[13];
#else
#error "Unsupported architecture"
#endif // architecture
NS_ENSURE_TRUE_VOID(sp);
NS_ENSURE_TRUE_VOID(mThreadStackBase);
size_t stackSize = std::min(intptr_t(ThreadContext::kMaxStackSize),
std::abs(sp - mThreadStackBase));
if (mContextToFill->mStackEnd) {
// Limit the start of stack to a certain location if specified.
stackSize = std::min(intptr_t(stackSize),
std::abs(sp - intptr_t(mContextToFill->mStackEnd)));
}
#ifndef MOZ_THREADSTACKHELPER_STACK_GROWS_DOWN
// If if the stack grows upwards, and we need to recalculate our
// stack copy's base address. Subtract sizeof(void*) so that the
// location pointed to by sp is included.
sp -= stackSize - sizeof(void*);
#endif
#ifndef MOZ_ASAN
memcpy(mContextToFill->mStack.get(), reinterpret_cast<void*>(sp), stackSize);
// Valgrind doesn't care about the access outside the stack frame, but
// the presence of uninitialised values on the stack does cause it to
// later report a lot of false errors when Breakpad comes to unwind it.
// So mark the extracted data as defined.
MOZ_MAKE_MEM_DEFINED(mContextToFill->mStack.get(), stackSize);
#else
// ASan will flag memcpy for access outside of stack frames,
// so roll our own memcpy here.
intptr_t* dst = reinterpret_cast<intptr_t*>(&mContextToFill->mStack[0]);
const intptr_t* src = reinterpret_cast<intptr_t*>(sp);
for (intptr_t len = stackSize; len > 0; len -= sizeof(*src)) {
*(dst++) = *(src++);
}
#endif
mContextToFill->mStackBase = uintptr_t(sp);
mContextToFill->mStackSize = stackSize;
mContextToFill->mValid = true;
#endif // MOZ_THREADSTACKHELPER_NATIVE
}
} // namespace mozilla