-#include <inttypes.h>
-#include <sys/mman.h>
-#include <unistd.h>
-#include <signal.h>
-#include <stdlib.h>
-#include <map>
-#include <set>
-#include <cstring>
-#include <cstdio>
-#include "snapshot.h"
-#include "snapshotimp.h"
-#include "mymemory.h"
-#include <fcntl.h>
-#include <assert.h>
-#include <pthread.h>
-#include <semaphore.h>
-#include <errno.h>
-#include <sys/wait.h>
-#include <ucontext.h>
-#include <sys/time.h>
-//extern declaration definition
-#define FAILURE(mesg) { printf("failed in the API: %s with errno relative message: %s\n", mesg, strerror( errno ) ); exit( -1 ); }
-#if USE_CHECKPOINTING
-struct SnapShot * snapshotrecord = NULL;
-struct Snapshot_t * sTheRecord = NULL;
-#else
-struct Snapshot_t * sTheRecord = NULL;
-#endif
-void BeginOperation( struct timeval * theStartTime ){
-#if 1
- gettimeofday( theStartTime, NULL );
-#endif
-}
-#if DEBUG
-struct timeval *starttime = NULL;
-#endif
-void DumpIntoLog( const char * filename, const char * message ){
-#if DEBUG
- static pid_t thePID = getpid();
- char newFn[ 1024 ] ={ 0 };
- sprintf( newFn,"%s-%d.txt", filename, thePID );
- FILE * myFile = fopen( newFn, "w+" );
- struct timeval theEndTime;
- BeginOperation( &theEndTime );
- double elapsed = ( theEndTime.tv_sec - starttime->tv_sec ) + ( theEndTime.tv_usec - starttime->tv_usec ) / 1000000.0;
- fprintf( myFile, "The timestamp %f:--> the message %s: the process id %d\n", elapsed, message, thePID );
- fflush( myFile );
- fclose( myFile );
- myFile = NULL;
-#endif
-}
-static ucontext_t savedSnapshotContext;
-static ucontext_t savedUserSnapshotContext;
-static int snapshotid = 0;
-/* Initialize snapshot data structure */
-#if USE_CHECKPOINTING
-void initSnapShotRecord(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions) {
- snapshotrecord=( struct SnapShot * )MYMALLOC(sizeof(struct SnapShot));
- snapshotrecord->regionsToSnapShot=( struct MemoryRegion * )MYMALLOC(sizeof(struct MemoryRegion)*nummemoryregions);
- snapshotrecord->backingStoreBasePtr= ( struct SnapShotPage * )MYMALLOC( sizeof( struct SnapShotPage ) * (numbackingpages + 1) );
- //Page align the backingstorepages
- snapshotrecord->backingStore=( struct SnapShotPage * )ReturnPageAlignedAddress((void*) ((uintptr_t)(snapshotrecord->backingStoreBasePtr)+sizeof(struct SnapShotPage)-1));
- snapshotrecord->backingRecords=( struct BackingPageRecord * )MYMALLOC(sizeof(struct BackingPageRecord)*numbackingpages);
- snapshotrecord->snapShots= ( struct SnapShotRecord * )MYMALLOC(sizeof(struct SnapShotRecord)*numsnapshots);
- snapshotrecord->lastSnapShot=0;
- snapshotrecord->lastBackingPage=0;
- snapshotrecord->lastRegion=0;
- snapshotrecord->maxRegions=nummemoryregions;
- snapshotrecord->maxBackingPages=numbackingpages;
- snapshotrecord->maxSnapShots=numsnapshots;
-}
-#endif //nothing to initialize for the fork based snapshotting.
-
-void HandlePF( int sig, siginfo_t *si, void * unused){
-#if USE_CHECKPOINTING
- if( si->si_code == SEGV_MAPERR ){
- printf("Real Fault at %llx\n", ( long long )si->si_addr);
- exit( EXIT_FAILURE );
- }
- void* addr = ReturnPageAlignedAddress(si->si_addr);
- unsigned int backingpage=snapshotrecord->lastBackingPage++; //Could run out of pages...
- if (backingpage==snapshotrecord->maxBackingPages) {
- printf("Out of backing pages at %llx\n", ( long long )si->si_addr);
- exit( EXIT_FAILURE );
- }
-
- //copy page
- memcpy(&(snapshotrecord->backingStore[backingpage]), addr, sizeof(struct SnapShotPage));
- //remember where to copy page back to
- snapshotrecord->backingRecords[backingpage].basePtrOfPage=addr;
- //set protection to read/write
- mprotect( addr, sizeof(struct SnapShotPage), PROT_READ | PROT_WRITE );
-#endif //nothing to handle for non snapshotting case.
-}
-
-//Return a page aligned address for the address being added
-//as a side effect the numBytes are also changed.
-void * ReturnPageAlignedAddress(void * addr) {
- return (void *)(((uintptr_t)addr)&~(PAGESIZE-1));
-}
-#ifdef __cplusplus
-extern "C" {
-#endif
-void createSharedLibrary(){
-#if !USE_CHECKPOINTING
- //step 1. create shared memory.
- if( sTheRecord ) return;
- int fd = shm_open( "/ModelChecker-Snapshotter", O_RDWR | O_CREAT, 0777 ); //universal permissions.
- if( -1 == fd ) FAILURE("shm_open");
- if( -1 == ftruncate( fd, ( size_t )SHARED_MEMORY_DEFAULT + ( size_t )STACK_SIZE_DEFAULT ) ) FAILURE( "ftruncate" );
- char * memMapBase = ( char * ) mmap( 0, ( size_t )SHARED_MEMORY_DEFAULT + ( size_t )STACK_SIZE_DEFAULT, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 );
- if( MAP_FAILED == memMapBase ) FAILURE("mmap");
- sTheRecord = ( struct Snapshot_t * )memMapBase;
- sTheRecord->mSharedMemoryBase = memMapBase + sizeof( struct Snapshot_t );
- sTheRecord->mStackBase = ( char * )memMapBase + ( size_t )SHARED_MEMORY_DEFAULT;
- sTheRecord->mStackSize = STACK_SIZE_DEFAULT;
- sTheRecord->mIDToRollback = -1;
- sTheRecord->currSnapShotID = 0;
-#endif
-}
-#ifdef __cplusplus
-}
-#endif
-void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions , MyFuncPtr entryPoint){
-#if USE_CHECKPOINTING
- struct sigaction sa;
- sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART;
- sigemptyset( &sa.sa_mask );
- sa.sa_sigaction = HandlePF;
- if( sigaction( SIGSEGV, &sa, NULL ) == -1 ){
- printf("SIGACTION CANNOT BE INSTALLED\n");
- exit(-1);
- }
- initSnapShotRecord(numbackingpages, numsnapshots, nummemoryregions);
- entryPoint();
-#else
- //add a signal to indicate that the process is going to terminate.
- struct sigaction sa;
- sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART;
- sigemptyset( &sa.sa_mask );
- sa.sa_sigaction = HandlePF;
- if( sigaction( SIGUSR1, &sa, NULL ) == -1 ){
- printf("SIGACTION CANNOT BE INSTALLED\n");
- exit(-1);
- }
- createSharedLibrary();
- #if DEBUG
- starttime = &(sTheRecord->startTimeGlobal);
- gettimeofday( starttime, NULL );
-#endif
- //step 2 setup the stack context.
-
- int alreadySwapped = 0;
- getcontext( &savedSnapshotContext );
- if( !alreadySwapped ){
- alreadySwapped = 1;
- ucontext_t currentContext, swappedContext, newContext;
- getcontext( &newContext );
- newContext.uc_stack.ss_sp = sTheRecord->mStackBase;
- newContext.uc_stack.ss_size = STACK_SIZE_DEFAULT;
- newContext.uc_link = ¤tContext;
- makecontext( &newContext, entryPoint, 0 );
- swapcontext( &swappedContext, &newContext );
- }
-
- //add the code to take a snapshot here...
- //to return to user process, do a second swapcontext...
- pid_t forkedID = 0;
- snapshotid = sTheRecord->currSnapShotID;
- bool swapContext = false;
- while( !sTheRecord->mbFinalize ){
- sTheRecord->currSnapShotID=snapshotid+1;
- forkedID = fork();
- if( 0 == forkedID ){
- ucontext_t currentContext;
-#if 0
- int dbg = 0;
- while( !dbg );
-#endif
- if( swapContext )
- swapcontext( ¤tContext, &( sTheRecord->mContextToRollback ) );
- else{
- swapcontext( ¤tContext, &savedUserSnapshotContext );
- }
- } else {
- int status;
- int retVal;
-#if DEBUG
- char mesg[ 1024 ] = { 0 };
- sprintf( mesg, "The process id of child is %d and the process id of this process is %d and snapshot id is %d", forkedID, getpid(), snapshotid );
- DumpIntoLog( "ModelSnapshot", mesg );
-#endif
- do {
- retVal=waitpid( forkedID, &status, 0 );
- } while( -1 == retVal && errno == EINTR );
-
- if( sTheRecord->mIDToRollback != snapshotid )
- exit(0);
- else{
- swapContext = true;
- }
- }
- }
-
-#endif
-}
-/* This function assumes that addr is page aligned */
-void addMemoryRegionToSnapShot( void * addr, unsigned int numPages) {
-#if USE_CHECKPOINTING
- unsigned int memoryregion=snapshotrecord->lastRegion++;
- if (memoryregion==snapshotrecord->maxRegions) {
- printf("Exceeded supported number of memory regions!\n");
- exit(-1);
- }
-
- snapshotrecord->regionsToSnapShot[ memoryregion ].basePtr=addr;
- snapshotrecord->regionsToSnapShot[ memoryregion ].sizeInPages=numPages;
-#endif //NOT REQUIRED IN THE CASE OF FORK BASED SNAPSHOTS.
-}
-//take snapshot
-snapshot_id takeSnapshot( ){
-#if USE_CHECKPOINTING
- for(unsigned int region=0; region<snapshotrecord->lastRegion;region++) {
- if( mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages*sizeof(struct SnapShotPage), PROT_READ ) == -1 ){
- printf("Failed to mprotect inside of takeSnapShot\n");
- exit(-1);
- }
- }
- unsigned int snapshot=snapshotrecord->lastSnapShot++;
- if (snapshot==snapshotrecord->maxSnapShots) {
- printf("Out of snapshots\n");
- exit(-1);
- }
- snapshotrecord->snapShots[snapshot].firstBackingPage=snapshotrecord->lastBackingPage;
-
- return snapshot;
-#else
- swapcontext( &savedUserSnapshotContext, &savedSnapshotContext );
- return snapshotid;
-#endif
-}
-void rollBack( snapshot_id theID ){
-#if USE_CHECKPOINTING
- std::map< void *, bool, std::less< void * >, MyAlloc< std::pair< const void *, bool > > > duplicateMap;
- for(unsigned int region=0; region<snapshotrecord->lastRegion;region++) {
- if( mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages*sizeof(struct SnapShotPage), PROT_READ | PROT_WRITE ) == -1 ){
- printf("Failed to mprotect inside of takeSnapShot\n");
- exit(-1);
- }
- }
- for(unsigned int page=snapshotrecord->snapShots[theID].firstBackingPage; page<snapshotrecord->lastBackingPage; page++) {
- bool oldVal = false;
- if( duplicateMap.find( snapshotrecord->backingRecords[page].basePtrOfPage ) != duplicateMap.end() ){
- oldVal = true;
- }
- else{
- duplicateMap[ snapshotrecord->backingRecords[page].basePtrOfPage ] = true;
- }
- if( !oldVal ){
- memcpy(snapshotrecord->backingRecords[page].basePtrOfPage, &snapshotrecord->backingStore[page], sizeof(struct SnapShotPage));
- }
- }
- snapshotrecord->lastSnapShot=theID;
- snapshotrecord->lastBackingPage=snapshotrecord->snapShots[theID].firstBackingPage;
- takeSnapshot(); //Make sure current snapshot is still good...All later ones are cleared
-#else
- sTheRecord->mIDToRollback = theID;
- int sTemp = 0;
- getcontext( &sTheRecord->mContextToRollback );
- if( !sTemp ){
- sTemp = 1;
-#if DEBUG
- DumpIntoLog( "ModelSnapshot", "Invoked rollback" );
-#endif
- exit( 0 );
- }
-#endif
-}
-
-void finalize(){
-#if !USE_CHECKPOINTING
- sTheRecord->mbFinalize = true;
-#endif
-}
-