Revert "fixing the segfault"

This reverts commit 7f305f5e6af465a60ec930832fbc6ec35bd8c693.

diff --git a/snapshot.cc b/snapshot.cc
index 9ff0ea20b169f16f09977b65a10055d2887fe73e..20980015fe50d9678e67a606f37e2a3b934aa3e6 100644 (file)
--- a/snapshot.cc
+++ b/snapshot.cc
@@ -36,17 +36,17 @@ struct timeval *starttime = NULL;
 #endif
 void DumpIntoLog( const char * filename, const char * message ){
 #if SSDEBUG
-   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;
+       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
 }
 #if !USE_CHECKPOINTING
@@ -57,233 +57,247 @@ 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;
+       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 * )PageAlignAddressUpward(snapshotrecord->backingStoreBasePtr);
+       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 );      
-  }
+       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 );  
+       //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
+       if (mprotect( addr, sizeof(struct SnapShotPage), PROT_READ | PROT_WRITE )) {
+               perror("mprotect");
+               // Handle error by quitting?
+       }
 #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));
+       return (void *)(((uintptr_t)addr)&~(PAGESIZE-1));
+}
+
+//Return a page aligned address for the address being added
+//as a side effect the numBytes are also changed.
+void * PageAlignAddressUpward(void * addr) {
+       return (void *)((((uintptr_t)addr)+PAGESIZE-1)&~(PAGESIZE-1));
 }
 #ifdef __cplusplus
 extern "C" {
 #endif
-void createSharedLibrary(){
+       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;
+               //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, unsigned int numheappages, 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);
-  }
-  mySpace = create_mspace( numheappages*PAGESIZE, 1 );
-  initSnapShotRecord(numbackingpages, numsnapshots, nummemoryregions);
-  addMemoryRegionToSnapShot(mySpace, numheappages);
-  entryPoint();
+       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);
+       
+       basemySpace=MYMALLOC((numheappages+1)*PAGESIZE);
+       void * pagealignedbase=PageAlignAddressUpward(basemySpace);
+       mySpace = create_mspace_with_base(pagealignedbase,  numheappages*PAGESIZE, 1 );
+       addMemoryRegionToSnapShot(pagealignedbase, numheappages);
+       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 SSDEBUG
-  starttime = &(sTheRecord->startTimeGlobal);
-  gettimeofday( starttime, NULL );
+       //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 SSDEBUG
+       starttime = &(sTheRecord->startTimeGlobal);
+       gettimeofday( starttime, NULL );
 #endif
-  //step 2 setup the stack context.
+       //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 = &currentContext;
-    makecontext( &newContext, entryPoint, 0 );
-    swapcontext( &swappedContext, &newContext );
-  }
+       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 = &currentContext;
+               makecontext( &newContext, entryPoint, 0 );
+               swapcontext( &swappedContext, &newContext );
+       }
   
-   //add the code to take a snapshot here...
+       //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;
+       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 );
+                       int dbg = 0;
+                       while( !dbg );
 #endif
-      if( swapContext )
-        swapcontext( &currentContext, &( sTheRecord->mContextToRollback ) );
+                       if( swapContext )
+                               swapcontext( &currentContext, &( sTheRecord->mContextToRollback ) );
                        else{
                                swapcontext( &currentContext, &savedUserSnapshotContext );      
                        }
-    } else {
-      int status;
-      int retVal;
+               } else {
+                       int status;
+                       int retVal;
 #if SSDEBUG
-      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 );
+                       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 { 
+                       do { 
                                retVal=waitpid( forkedID, &status, 0 );
-      } while( -1 == retVal && errno == EINTR );
+                       } while( -1 == retVal && errno == EINTR );
 
-      if( sTheRecord->mIDToRollback != snapshotid )
-                         exit(0);
-      else{
-         swapContext = true;
-      }
-    }
-  }
+                       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);
-  }
+       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;
+       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;
+       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 ){
+                       perror("mprotect");
+                       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;
+       return snapshot;
 #else
-  swapcontext( &savedUserSnapshotContext, &savedSnapshotContext );
-  return snapshotid;
+       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
+       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 ){
+                       perror("mprotect");
+                       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;
+       sTheRecord->mIDToRollback = theID;
+       int sTemp = 0;
+       getcontext( &sTheRecord->mContextToRollback );
+       if( !sTemp ){
+               sTemp = 1;
 #if SSDEBUG
-       DumpIntoLog( "ModelSnapshot", "Invoked rollback" ); 
+               DumpIntoLog( "ModelSnapshot", "Invoked rollback" ); 
 #endif
-       exit( 0 );
-  }
+               exit( 0 );
+       }
 #endif
 }
 
 void finalize(){
 #if !USE_CHECKPOINTING
-  sTheRecord->mbFinalize = true;
+       sTheRecord->mbFinalize = true;
 #endif
 }