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Avoid NavCache races on multiple copies rebuilding

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If impatient users start multiple copies of FlightGear when a cache
rebuild is required, we can get into a mess. Use an additional
named mutex on Windows to avoid this situation, and block the secondary
copies until the primary instance has completed its cache rebuild.

Sentry-Id: FLIGHTGEAR-8D
Sentry-Id: FLIGHTGEAR-FY
This commit is contained in:
James Turner 2020-11-10 11:42:46 +00:00
parent 2d7e7b3df6
commit 134e06af68
3 changed files with 143 additions and 31 deletions
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38
src/GUI/QtLauncher.cxx
View file

@ -99,16 +99,43 @@ void initNavCache()
const char* baseLabelKey = QT_TRANSLATE_NOOP("initNavCache", "Initialising navigation data, this may take several minutes");
QString baseLabel= qApp->translate("initNavCache", baseLabelKey);
const auto wflags = Qt::Dialog | Qt::CustomizeWindowHint | Qt::WindowTitleHint | Qt::WindowSystemMenuHint | Qt::MSWindowsFixedSizeDialogHint;
if (NavDataCache::isAnotherProcessRebuilding()) {
const char* waitForOtherMsg = QT_TRANSLATE_NOOP("initNavCache", "Another copy of FlightGear is creating the navigation database. Waiting for it to finish.");
QString m = qApp->translate("initNavCache", waitForOtherMsg);
QProgressDialog waitForRebuild(m,
QString() /* cancel text */,
0, 0, Q_NULLPTR,
wflags);
waitForRebuild.setWindowModality(Qt::WindowModal);
waitForRebuild.setMinimumWidth(600);
waitForRebuild.setAutoReset(false);
waitForRebuild.setAutoClose(false);
waitForRebuild.show();
QTimer updateTimer;
updateTimer.setInterval(500);
QObject::connect(&updateTimer, &QTimer::timeout, [&waitForRebuild]() {
if (!NavDataCache::isAnotherProcessRebuilding()) {
waitForRebuild.done(0);
return;
}
});
updateTimer.start(); // timer won't actually run until we process events
waitForRebuild.exec();
updateTimer.stop();
}
NavDataCache* cache = NavDataCache::createInstance();
if (cache->isRebuildRequired()) {
QProgressDialog rebuildProgress(baseLabel,
QString() /* cancel text */,
0, 100, Q_NULLPTR,
Qt::Dialog
| Qt::CustomizeWindowHint
| Qt::WindowTitleHint
| Qt::WindowSystemMenuHint
| Qt::MSWindowsFixedSizeDialogHint);
wflags);
rebuildProgress.setWindowModality(Qt::WindowModal);
rebuildProgress.setMinimumWidth(600);
rebuildProgress.setAutoReset(false);
@ -117,6 +144,7 @@ void initNavCache()
QTimer updateTimer;
updateTimer.setInterval(100);
QObject::connect(&updateTimer, &QTimer::timeout, [&cache, &rebuildProgress, &baseLabel]() {
auto phase = cache->rebuild();
if (phase == NavDataCache::REBUILD_DONE) {

112
src/Navaids/NavDataCache.cxx
View file

@ -46,6 +46,11 @@
#include "fg_sqlite3.h"
#endif
#if defined(SG_WINDOWS)
#define WIN32_LEAN_AND_MEAN // less crap :)
#include <Windows.h>
#endif
// SimGear
#include <simgear/sg_inlines.h>
#include <simgear/structure/exception.hxx>
@ -56,26 +61,26 @@
#include <simgear/misc/strutils.hxx>
#include <simgear/threads/SGThread.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include <Main/options.hxx>
#include "CacheSchema.h"
#include "PositionedOctree.hxx"
#include "fix.hxx"
#include "markerbeacon.hxx"
#include "navrecord.hxx"
#include <Airports/airport.hxx>
#include <Airports/runways.hxx>
#include "poidb.hxx"
#include <ATC/CommStation.hxx>
#include "fix.hxx"
#include <Airports/airport.hxx>
#include <Airports/apt_loader.hxx>
#include <Airports/gnnode.hxx>
#include <Airports/parking.hxx>
#include <Airports/runways.hxx>
#include <GUI/MessageBox.hxx>
#include <Main/fg_props.hxx>
#include <Main/globals.hxx>
#include <Main/options.hxx>
#include <Main/sentryIntegration.hxx>
#include <Navaids/airways.hxx>
#include <Navaids/fixlist.hxx>
#include <Navaids/navdb.hxx>
#include "PositionedOctree.hxx"
#include <Airports/apt_loader.hxx>
#include <Navaids/airways.hxx>
#include "poidb.hxx"
#include <Airports/parking.hxx>
#include <Airports/gnnode.hxx>
#include "CacheSchema.h"
#include <GUI/MessageBox.hxx>
#include <Navaids/airways.hxx>
using std::string;
@ -264,6 +269,10 @@ public:
throw sg_exception("Nav-cache file is not writeable");
}
if (outer->isAnotherProcessRebuilding()) {
SG_LOG(SG_NAVCACHE, SG_ALERT, "NavDataCache: init() while another processing is rebuilding the DB");
}
int openFlags = readOnly ? SQLITE_OPEN_READONLY :
(SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE);
std::string pathUtf8 = path.utf8Str();
@ -463,6 +472,7 @@ public:
{
if (!execSelect(stmt)) {
SG_LOG(SG_NAVCACHE, SG_WARN, "empty SELECT running:\n\t" << sqlite3_sql(stmt));
flightgear::sentryReportException("empty SELECT running:" + std::string{sqlite3_sql(stmt)});
throw sg_exception("no results returned for select", sqlite3_sql(stmt));
}
}
@ -697,6 +707,8 @@ public:
const SGGeod& pos,
PositionedID airport)
{
SG_UNUSED(id);
sqlite3_bind_int64(loadCommStation, 1, rowId);
execSelect1(loadCommStation);
@ -1357,8 +1369,36 @@ bool NavDataCache::isRebuildRequired()
return false;
}
#if defined(SG_WINDOWS)
static HANDLE static_fgNavCacheRebuildMutex = nullptr;
#endif
NavDataCache::RebuildPhase NavDataCache::rebuild()
{
#if defined(SG_WINDOWS)
if (static_fgNavCacheRebuildMutex == nullptr) {
// avoid multiple copies racing on the nav-cache build
static_fgNavCacheRebuildMutex = CreateMutexA(nullptr, FALSE, "org.flightgear.fgfs.rebuild-navcache");
if (static_fgNavCacheRebuildMutex == nullptr) {
flightgear::fatalMessageBoxThenExit("Multiple copies of Flightgear initializing",
"Failed to create mutex for nav-cache rebuild protection:" + std::to_string(GetLastError()));
} else if (GetLastError() == ERROR_ALREADY_EXISTS) {
flightgear::fatalMessageBoxThenExit("Multiple copies of Flightgear initializing",
"Multiple copies of FlightGear are trying to initialise the same navigation database. "
"This means something has gone badly wrong: please report this error.");
}
// accquire the mutex, so that other processes can check the status.
const int result = WaitForSingleObject(static_fgNavCacheRebuildMutex, 100);
if (result != WAIT_OBJECT_0) {
flightgear::fatalMessageBoxThenExit("Multiple copies of Flightgear initializing",
"Failed to lock mutex for nav-cache rebuild protection:" + std::to_string(GetLastError()));
}
}
#endif
if (!d->rebuilder.get()) {
d->rebuilder.reset(new RebuildThread(this));
d->rebuilder->start();
@ -1368,10 +1408,49 @@ NavDataCache::RebuildPhase NavDataCache::rebuild()
RebuildPhase phase = d->rebuilder->currentPhase();
if (phase == REBUILD_DONE) {
d->rebuilder.reset(); // all done!
#if defined(SG_WINDOWS)
ReleaseMutex(static_fgNavCacheRebuildMutex);
#endif
}
return phase;
}
bool NavDataCache::isAnotherProcessRebuilding()
{
#if defined(SG_WINDOWS)
if (!static_fgNavCacheRebuildMutex) {
static_fgNavCacheRebuildMutex = OpenMutexA(SYNCHRONIZE, FALSE, "org.flightgear.fgfs.rebuild-navcache");
if (!static_fgNavCacheRebuildMutex) {
// this is the common case: no other fgfs.exe is doing a rebuild, so
// the mutex does not exist. Simple, we are done
if (GetLastError() == ERROR_FILE_NOT_FOUND) {
return false;
}
flightgear::fatalMessageBoxThenExit("Multiple copies of Flightgear initializing",
"Unable to check if other copies of FlightGear are initializing. "
"Please report this error.");
}
}
// poll the named mutex
auto result = WaitForSingleObject(static_fgNavCacheRebuildMutex, 0);
if (result == WAIT_OBJECT_0) {
// we accquired it, release it and we're done
// (there could be multiple read-only copies in this situation)
ReleaseMutex(static_fgNavCacheRebuildMutex);
CloseHandle(static_fgNavCacheRebuildMutex);
return false;
}
// failed to accquire the mutex, so assume another FGFS.exe is rebuilding,
// the GU should wait.
return true;
#else
return false; // not implemented on macOS / Linux for now
#endif
}
unsigned int NavDataCache::rebuildPhaseCompletionPercentage() const
{
if (!d->rebuilder.get()) {
@ -1692,6 +1771,7 @@ void NavDataCache::commitTransaction()
// it's active, the DB was rolled-back
if (sqlite3_get_autocommit(d->db)) {
SG_LOG(SG_NAVCACHE, SG_ALERT, "commit: was rolled back!" << retries);
flightgear::sentryReportException("DB commit was rolled back");
d->transactionAborted = true;
break;
}
@ -1707,6 +1787,7 @@ void NavDataCache::commitTransaction()
string errMsg;
if (result != SQLITE_DONE) {
errMsg = sqlite3_errmsg(d->db);
flightgear::sentryReportException("DB error:" + errMsg + " running " + std::string{sqlite3_sql(q)});
SG_LOG(SG_NAVCACHE, SG_ALERT, "Sqlite error:" << errMsg << " for " << result
<< " while running:\n\t" << sqlite3_sql(q));
}
@ -1718,6 +1799,7 @@ void NavDataCache::commitTransaction()
void NavDataCache::abortTransaction()
{
SG_LOG(SG_NAVCACHE, SG_WARN, "NavCache: aborting transaction");
flightgear::sentryReportException("DB aborting transactino");
assert(d->transactionLevel > 0);
if (--d->transactionLevel == 0) {

2
src/Navaids/NavDataCache.hxx
View file

@ -109,6 +109,8 @@ public:
*/
bool isRebuildRequired();
static bool isAnotherProcessRebuilding();
enum RebuildPhase
{
REBUILD_UNKNOWN = 0,