X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=snapshot.cc;h=0362994daf50354d6a34991ab07294fed4fc19ce;hb=34e232a12096c3fce512ec06d921329edf8fcb3a;hp=83d22b4f5939b31ec7689177aed381b057966697;hpb=d88196987e572dcb561e8b1eabb3409c4491d460;p=model-checker.git

diff --git a/snapshot.cc b/snapshot.cc
index 83d22b4..0362994 100644
--- a/snapshot.cc
+++ b/snapshot.cc
@@ -61,7 +61,7 @@ void initSnapShotRecord(unsigned int numbackingpages, unsigned int numsnapshots,
 	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->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;
@@ -77,13 +77,13 @@ 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 );	
+		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 );	
+		exit( EXIT_FAILURE );
 	}
 
 	//copy page
@@ -103,6 +103,12 @@ void HandlePF( int sig, siginfo_t *si, void * unused){
 void * ReturnPageAlignedAddress(void * addr) {
 	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
@@ -128,8 +134,15 @@ extern "C" {
 #endif
 void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions, unsigned int numheappages, MyFuncPtr entryPoint){
 #if USE_CHECKPOINTING
+  /* Setup a stack for our signal handler....  */
+  stack_t ss;
+  ss.ss_sp = MYMALLOC(SIGSTACKSIZE);
+  ss.ss_size = SIGSTACKSIZE;
+  ss.ss_flags = 0;
+  sigaltstack(&ss, NULL);
+
 	struct sigaction sa;
-	sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART;
+	sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART | SA_ONSTACK;
 	sigemptyset( &sa.sa_mask );
 	sa.sa_sigaction = HandlePF;
 	if( sigaction( SIGSEGV, &sa, NULL ) == -1 ){
@@ -137,9 +150,9 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 		exit(-1);
 	}
 	initSnapShotRecord(numbackingpages, numsnapshots, nummemoryregions);
-	
+
 	basemySpace=MYMALLOC((numheappages+1)*PAGESIZE);
-	void * pagealignedbase=(void *)((((uintptr_t)basemySpace)+PAGESIZE-1)&~(PAGESIZE-1));
+	void * pagealignedbase=PageAlignAddressUpward(basemySpace);
 	mySpace = create_mspace_with_base(pagealignedbase,  numheappages*PAGESIZE, 1 );
 	addMemoryRegionToSnapShot(pagealignedbase, numheappages);
 	entryPoint();
@@ -159,7 +172,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 	gettimeofday( starttime, NULL );
 #endif
 	//step 2 setup the stack context.
- 
+
 	int alreadySwapped = 0;
 	getcontext( &savedSnapshotContext );
 	if( !alreadySwapped ){
@@ -172,7 +185,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 		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;
@@ -181,7 +194,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 	while( !sTheRecord->mbFinalize ){
 		sTheRecord->currSnapShotID=snapshotid+1;
 		forkedID = fork();
-		if( 0 == forkedID ){ 
+		if( 0 == forkedID ){
 			ucontext_t currentContext;
 #if 0
 			int dbg = 0;
@@ -190,7 +203,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 			if( swapContext )
 				swapcontext( &currentContext, &( sTheRecord->mContextToRollback ) );
 			else{
-				swapcontext( &currentContext, &savedUserSnapshotContext );      
+				swapcontext( &currentContext, &savedUserSnapshotContext );
 			}
 		} else {
 			int status;
@@ -200,7 +213,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 			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 );
 
@@ -211,7 +224,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 			}
 		}
 	}
-  
+
 #endif
 }
 /* This function assumes that addr is page aligned */
@@ -222,7 +235,7 @@ void addMemoryRegionToSnapShot( void * addr, unsigned int numPages) {
 		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.
@@ -235,7 +248,7 @@ snapshot_id takeSnapshot( ){
 			perror("mprotect");
 			printf("Failed to mprotect inside of takeSnapShot\n");
 			exit(-1);
-		}		
+		}
 	}
 	unsigned int snapshot=snapshotrecord->lastSnapShot++;
 	if (snapshot==snapshotrecord->maxSnapShots) {
@@ -243,7 +256,7 @@ snapshot_id takeSnapshot( ){
 		exit(-1);
 	}
 	snapshotrecord->snapShots[snapshot].firstBackingPage=snapshotrecord->lastBackingPage;
-  
+
 	return snapshot;
 #else
 	swapcontext( &savedUserSnapshotContext, &savedSnapshotContext );
@@ -258,15 +271,15 @@ void rollBack( snapshot_id theID ){
 			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;          
+			oldVal = true;
 		}
 		else{
-			duplicateMap[ snapshotrecord->backingRecords[page].basePtrOfPage ] = true;    
+			duplicateMap[ snapshotrecord->backingRecords[page].basePtrOfPage ] = true;
 		}
 		if(  !oldVal ){
 			memcpy(snapshotrecord->backingRecords[page].basePtrOfPage, &snapshotrecord->backingStore[page], sizeof(struct SnapShotPage));
@@ -282,7 +295,7 @@ void rollBack( snapshot_id theID ){
 	if( !sTemp ){
 		sTemp = 1;
 #if SSDEBUG
-		DumpIntoLog( "ModelSnapshot", "Invoked rollback" ); 
+		DumpIntoLog( "ModelSnapshot", "Invoked rollback" );
 #endif
 		exit( 0 );
 	}