282 lines
7.4 KiB
C++
282 lines
7.4 KiB
C++
//===--- CrashRecoveryContext.cpp - Crash Recovery ------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Support/CrashRecoveryContext.h"
|
|
#include "llvm/ADT/SmallString.h"
|
|
#include "llvm/Config/config.h"
|
|
#include "llvm/Support/Mutex.h"
|
|
#include "llvm/Support/ThreadLocal.h"
|
|
#include <setjmp.h>
|
|
#include <cstdio>
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
struct CrashRecoveryContextImpl;
|
|
|
|
static sys::ThreadLocal<const CrashRecoveryContextImpl> CurrentContext;
|
|
|
|
struct CrashRecoveryContextImpl {
|
|
CrashRecoveryContext *CRC;
|
|
std::string Backtrace;
|
|
::jmp_buf JumpBuffer;
|
|
volatile unsigned Failed : 1;
|
|
|
|
public:
|
|
CrashRecoveryContextImpl(CrashRecoveryContext *CRC) : CRC(CRC),
|
|
Failed(false) {
|
|
CurrentContext.set(this);
|
|
}
|
|
~CrashRecoveryContextImpl() {
|
|
CurrentContext.erase();
|
|
}
|
|
|
|
void HandleCrash() {
|
|
// Eliminate the current context entry, to avoid re-entering in case the
|
|
// cleanup code crashes.
|
|
CurrentContext.erase();
|
|
|
|
assert(!Failed && "Crash recovery context already failed!");
|
|
Failed = true;
|
|
|
|
// FIXME: Stash the backtrace.
|
|
|
|
// Jump back to the RunSafely we were called under.
|
|
longjmp(JumpBuffer, 1);
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
static sys::Mutex gCrashRecoveryContexMutex;
|
|
static bool gCrashRecoveryEnabled = false;
|
|
|
|
static sys::ThreadLocal<const CrashRecoveryContextCleanup>
|
|
tlIsRecoveringFromCrash;
|
|
|
|
CrashRecoveryContextCleanup::~CrashRecoveryContextCleanup() {}
|
|
|
|
CrashRecoveryContext::~CrashRecoveryContext() {
|
|
// Reclaim registered resources.
|
|
CrashRecoveryContextCleanup *i = head;
|
|
tlIsRecoveringFromCrash.set(head);
|
|
while (i) {
|
|
CrashRecoveryContextCleanup *tmp = i;
|
|
i = tmp->next;
|
|
tmp->cleanupFired = true;
|
|
tmp->recoverResources();
|
|
delete tmp;
|
|
}
|
|
tlIsRecoveringFromCrash.erase();
|
|
|
|
CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
|
|
delete CRCI;
|
|
}
|
|
|
|
bool CrashRecoveryContext::isRecoveringFromCrash() {
|
|
return tlIsRecoveringFromCrash.get() != 0;
|
|
}
|
|
|
|
CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
|
|
if (!gCrashRecoveryEnabled)
|
|
return 0;
|
|
|
|
const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
|
|
if (!CRCI)
|
|
return 0;
|
|
|
|
return CRCI->CRC;
|
|
}
|
|
|
|
void CrashRecoveryContext::registerCleanup(CrashRecoveryContextCleanup *cleanup)
|
|
{
|
|
if (!cleanup)
|
|
return;
|
|
if (head)
|
|
head->prev = cleanup;
|
|
cleanup->next = head;
|
|
head = cleanup;
|
|
}
|
|
|
|
void
|
|
CrashRecoveryContext::unregisterCleanup(CrashRecoveryContextCleanup *cleanup) {
|
|
if (!cleanup)
|
|
return;
|
|
if (cleanup == head) {
|
|
head = cleanup->next;
|
|
if (head)
|
|
head->prev = 0;
|
|
}
|
|
else {
|
|
cleanup->prev->next = cleanup->next;
|
|
if (cleanup->next)
|
|
cleanup->next->prev = cleanup->prev;
|
|
}
|
|
delete cleanup;
|
|
}
|
|
|
|
#ifdef LLVM_ON_WIN32
|
|
|
|
// FIXME: No real Win32 implementation currently.
|
|
|
|
void CrashRecoveryContext::Enable() {
|
|
sys::ScopedLock L(gCrashRecoveryContexMutex);
|
|
|
|
if (gCrashRecoveryEnabled)
|
|
return;
|
|
|
|
gCrashRecoveryEnabled = true;
|
|
}
|
|
|
|
void CrashRecoveryContext::Disable() {
|
|
sys::ScopedLock L(gCrashRecoveryContexMutex);
|
|
|
|
if (!gCrashRecoveryEnabled)
|
|
return;
|
|
|
|
gCrashRecoveryEnabled = false;
|
|
}
|
|
|
|
#else
|
|
|
|
// Generic POSIX implementation.
|
|
//
|
|
// This implementation relies on synchronous signals being delivered to the
|
|
// current thread. We use a thread local object to keep track of the active
|
|
// crash recovery context, and install signal handlers to invoke HandleCrash on
|
|
// the active object.
|
|
//
|
|
// This implementation does not to attempt to chain signal handlers in any
|
|
// reliable fashion -- if we get a signal outside of a crash recovery context we
|
|
// simply disable crash recovery and raise the signal again.
|
|
|
|
#include <signal.h>
|
|
|
|
static int Signals[] = { SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGSEGV, SIGTRAP };
|
|
static const unsigned NumSignals = sizeof(Signals) / sizeof(Signals[0]);
|
|
static struct sigaction PrevActions[NumSignals];
|
|
|
|
static void CrashRecoverySignalHandler(int Signal) {
|
|
// Lookup the current thread local recovery object.
|
|
const CrashRecoveryContextImpl *CRCI = CurrentContext.get();
|
|
|
|
if (!CRCI) {
|
|
// We didn't find a crash recovery context -- this means either we got a
|
|
// signal on a thread we didn't expect it on, the application got a signal
|
|
// outside of a crash recovery context, or something else went horribly
|
|
// wrong.
|
|
//
|
|
// Disable crash recovery and raise the signal again. The assumption here is
|
|
// that the enclosing application will terminate soon, and we won't want to
|
|
// attempt crash recovery again.
|
|
//
|
|
// This call of Disable isn't thread safe, but it doesn't actually matter.
|
|
CrashRecoveryContext::Disable();
|
|
raise(Signal);
|
|
|
|
// The signal will be thrown once the signal mask is restored.
|
|
return;
|
|
}
|
|
|
|
// Unblock the signal we received.
|
|
sigset_t SigMask;
|
|
sigemptyset(&SigMask);
|
|
sigaddset(&SigMask, Signal);
|
|
sigprocmask(SIG_UNBLOCK, &SigMask, 0);
|
|
|
|
if (CRCI)
|
|
const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
|
|
}
|
|
|
|
void CrashRecoveryContext::Enable() {
|
|
sys::ScopedLock L(gCrashRecoveryContexMutex);
|
|
|
|
if (gCrashRecoveryEnabled)
|
|
return;
|
|
|
|
gCrashRecoveryEnabled = true;
|
|
|
|
// Setup the signal handler.
|
|
struct sigaction Handler;
|
|
Handler.sa_handler = CrashRecoverySignalHandler;
|
|
Handler.sa_flags = 0;
|
|
sigemptyset(&Handler.sa_mask);
|
|
|
|
for (unsigned i = 0; i != NumSignals; ++i) {
|
|
sigaction(Signals[i], &Handler, &PrevActions[i]);
|
|
}
|
|
}
|
|
|
|
void CrashRecoveryContext::Disable() {
|
|
sys::ScopedLock L(gCrashRecoveryContexMutex);
|
|
|
|
if (!gCrashRecoveryEnabled)
|
|
return;
|
|
|
|
gCrashRecoveryEnabled = false;
|
|
|
|
// Restore the previous signal handlers.
|
|
for (unsigned i = 0; i != NumSignals; ++i)
|
|
sigaction(Signals[i], &PrevActions[i], 0);
|
|
}
|
|
|
|
#endif
|
|
|
|
bool CrashRecoveryContext::RunSafely(void (*Fn)(void*), void *UserData) {
|
|
// If crash recovery is disabled, do nothing.
|
|
if (gCrashRecoveryEnabled) {
|
|
assert(!Impl && "Crash recovery context already initialized!");
|
|
CrashRecoveryContextImpl *CRCI = new CrashRecoveryContextImpl(this);
|
|
Impl = CRCI;
|
|
|
|
if (setjmp(CRCI->JumpBuffer) != 0) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
Fn(UserData);
|
|
return true;
|
|
}
|
|
|
|
void CrashRecoveryContext::HandleCrash() {
|
|
CrashRecoveryContextImpl *CRCI = (CrashRecoveryContextImpl *) Impl;
|
|
assert(CRCI && "Crash recovery context never initialized!");
|
|
CRCI->HandleCrash();
|
|
}
|
|
|
|
const std::string &CrashRecoveryContext::getBacktrace() const {
|
|
CrashRecoveryContextImpl *CRC = (CrashRecoveryContextImpl *) Impl;
|
|
assert(CRC && "Crash recovery context never initialized!");
|
|
assert(CRC->Failed && "No crash was detected!");
|
|
return CRC->Backtrace;
|
|
}
|
|
|
|
//
|
|
|
|
namespace {
|
|
struct RunSafelyOnThreadInfo {
|
|
void (*UserFn)(void*);
|
|
void *UserData;
|
|
CrashRecoveryContext *CRC;
|
|
bool Result;
|
|
};
|
|
}
|
|
|
|
static void RunSafelyOnThread_Dispatch(void *UserData) {
|
|
RunSafelyOnThreadInfo *Info =
|
|
reinterpret_cast<RunSafelyOnThreadInfo*>(UserData);
|
|
Info->Result = Info->CRC->RunSafely(Info->UserFn, Info->UserData);
|
|
}
|
|
bool CrashRecoveryContext::RunSafelyOnThread(void (*Fn)(void*), void *UserData,
|
|
unsigned RequestedStackSize) {
|
|
RunSafelyOnThreadInfo Info = { Fn, UserData, this, false };
|
|
llvm_execute_on_thread(RunSafelyOnThread_Dispatch, &Info, RequestedStackSize);
|
|
return Info.Result;
|
|
}
|