#include <signal.h>
#include <stdlib.h>
#include <map>
-#include <set>
#include <cstring>
#include <cstdio>
#include "snapshot.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;
+
+#define FAILURE(mesg) { printf("failed in the API: %s with errno relative message: %s\n", mesg, strerror( errno ) ); exit(EXIT_FAILURE); }
+
+#ifdef CONFIG_SSDEBUG
+#define SSDEBUG printf
#else
-struct Snapshot_t * sTheRecord = NULL;
-#endif
-void BeginOperation( struct timeval * theStartTime ){
-#if 1
- gettimeofday( theStartTime, NULL );
+#define SSDEBUG(...) do { } while (0)
#endif
-}
-#if SSDEBUG
-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;
+
+/* extern declaration definition */
+#if USE_MPROTECT_SNAPSHOT
+struct SnapShot * snapshotrecord = NULL;
+#else
+struct Snapshot * sTheRecord = NULL;
#endif
-}
-#if !USE_CHECKPOINTING
+
+#if !USE_MPROTECT_SNAPSHOT
static ucontext_t savedSnapshotContext;
static ucontext_t savedUserSnapshotContext;
-static int snapshotid = 0;
+static snapshot_id snapshotid = 0;
#endif
-/* Initialize snapshot data structure */
-#if USE_CHECKPOINTING
+
+/** PageAlignedAdressUpdate return a page aligned address for the
+ * address being added as a side effect the numBytes are also changed.
+ */
+static void * PageAlignAddressUpward(void * addr) {
+ return (void *)((((uintptr_t)addr)+PAGESIZE-1)&~(PAGESIZE-1));
+}
+
+#if USE_MPROTECT_SNAPSHOT
+
+/** ReturnPageAlignedAddress returns a page aligned address for the
+ * address being added as a side effect the numBytes are also changed.
+ */
+static void * ReturnPageAlignedAddress(void * addr) {
+ return (void *)(((uintptr_t)addr)&~(PAGESIZE-1));
+}
+
+/** The initSnapShotRecord method initialized the snapshotting data
+ * structures for the mprotect based snapshot.
+ */
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->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;
}
#endif //nothing to initialize for the fork based snapshotting.
+/** HandlePF is the page fault handler for mprotect based snapshotting
+ * algorithm.
+ */
+
void HandlePF( int sig, siginfo_t *si, void * unused){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
if( si->si_code == SEGV_MAPERR ){
- printf("Real Fault at %llx\n", ( long long )si->si_addr);
- exit( EXIT_FAILURE );
+ printf("Real Fault at %p\n", 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 );
+ printf("Out of backing pages at %p\n", si->si_addr);
+ exit( EXIT_FAILURE );
}
//copy page
#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;
+void createSharedLibrary(){
+#if !USE_MPROTECT_SNAPSHOT
+ //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 * )memMapBase;
+ sTheRecord->mSharedMemoryBase = memMapBase + sizeof( struct Snapshot );
+ sTheRecord->mStackBase = ( char * )memMapBase + ( size_t )SHARED_MEMORY_DEFAULT;
+ sTheRecord->mStackSize = STACK_SIZE_DEFAULT;
+ sTheRecord->mIDToRollback = -1;
+ sTheRecord->currSnapShotID = 0;
+ sTheRecord->mbFinalize = false;
#endif
- }
-#ifdef __cplusplus
}
-#endif
-void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions, unsigned int numheappages, MyFuncPtr entryPoint){
-#if USE_CHECKPOINTING
+
+/** The initSnapShotLibrary function initializes the Snapshot library.
+ * @param entryPoint the function that should run the program.
+ */
+void initSnapShotLibrary(unsigned int numbackingpages,
+ unsigned int numsnapshots, unsigned int nummemoryregions,
+ unsigned int numheappages, VoidFuncPtr entryPoint) {
+#if USE_MPROTECT_SNAPSHOT
+ /* 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;
+#ifdef MAC
+ if( sigaction( SIGBUS, &sa, NULL ) == -1 ){
+ printf("SIGACTION CANNOT BE INSTALLED\n");
+ exit(EXIT_FAILURE);
+ }
+#endif
if( sigaction( SIGSEGV, &sa, NULL ) == -1 ){
printf("SIGACTION CANNOT BE INSTALLED\n");
- exit(-1);
+ exit(EXIT_FAILURE);
}
+
initSnapShotRecord(numbackingpages, numsnapshots, nummemoryregions);
- mySpace = create_mspace( numheappages*PAGESIZE, 1 );
- addMemoryRegionToSnapShot(mySpace, numheappages);
+
+ // EVIL HACK: We need to make sure that calls into the HandlePF method don't cause dynamic links
+ // The problem is that we end up protecting state in the dynamic linker...
+ // Solution is to call our signal handler before we start protecting stuff...
+
+ siginfo_t si;
+ memset(&si, 0, sizeof(si));
+ si.si_addr=ss.ss_sp;
+ HandlePF(SIGSEGV, &si, NULL);
+ snapshotrecord->lastBackingPage--; //remove the fake page we copied
+
+ 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);
- }
+
+ basemySpace=system_malloc((numheappages+1)*PAGESIZE);
+ void * pagealignedbase=PageAlignAddressUpward(basemySpace);
+ mySpace = create_mspace_with_base(pagealignedbase, numheappages*PAGESIZE, 1 );
createSharedLibrary();
-#if SSDEBUG
- starttime = &(sTheRecord->startTimeGlobal);
- gettimeofday( starttime, NULL );
-#endif
+
//step 2 setup the stack context.
-
+
int alreadySwapped = 0;
getcontext( &savedSnapshotContext );
if( !alreadySwapped ){
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;
while( !sTheRecord->mbFinalize ){
sTheRecord->currSnapShotID=snapshotid+1;
forkedID = fork();
- if( 0 == forkedID ){
+ if( 0 == forkedID ){
ucontext_t currentContext;
#if 0
int dbg = 0;
if( swapContext )
swapcontext( ¤tContext, &( sTheRecord->mContextToRollback ) );
else{
- swapcontext( ¤tContext, &savedUserSnapshotContext );
+ swapcontext( ¤tContext, &savedUserSnapshotContext );
}
} 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 );
-#endif
- do {
+
+ SSDEBUG("The process id of child is %d and the process id of this process is %d and snapshot id is %d",
+ forkedID, getpid(), snapshotid );
+
+ do {
retVal=waitpid( forkedID, &status, 0 );
} while( -1 == retVal && errno == EINTR );
if( sTheRecord->mIDToRollback != snapshotid )
- exit(0);
+ exit(EXIT_SUCCESS);
else{
swapContext = true;
}
}
}
-
+
#endif
}
-/* This function assumes that addr is page aligned */
+
+/** The addMemoryRegionToSnapShot function assumes that addr is page aligned.
+ */
void addMemoryRegionToSnapShot( void * addr, unsigned int numPages) {
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
unsigned int memoryregion=snapshotrecord->lastRegion++;
if (memoryregion==snapshotrecord->maxRegions) {
printf("Exceeded supported number of memory regions!\n");
- exit(-1);
+ exit(EXIT_FAILURE);
}
-
+
snapshotrecord->regionsToSnapShot[ memoryregion ].basePtr=addr;
snapshotrecord->regionsToSnapShot[ memoryregion ].sizeInPages=numPages;
#endif //NOT REQUIRED IN THE CASE OF FORK BASED SNAPSHOTS.
}
-//take snapshot
+
+/** The takeSnapshot function takes a snapshot.
+ * @return The snapshot identifier.
+ */
+
snapshot_id takeSnapshot( ){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
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);
- }
+ exit(EXIT_FAILURE);
+ }
}
unsigned int snapshot=snapshotrecord->lastSnapShot++;
if (snapshot==snapshotrecord->maxSnapShots) {
printf("Out of snapshots\n");
- exit(-1);
+ exit(EXIT_FAILURE);
}
snapshotrecord->snapShots[snapshot].firstBackingPage=snapshotrecord->lastBackingPage;
-
+
return snapshot;
#else
swapcontext( &savedUserSnapshotContext, &savedSnapshotContext );
return snapshotid;
#endif
}
+
+/** The rollBack function rollback to the given snapshot identifier.
+ * @param theID is the snapshot identifier to rollback to.
+ */
+
void rollBack( snapshot_id theID ){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
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);
- }
+ exit(EXIT_FAILURE);
+ }
}
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));
getcontext( &sTheRecord->mContextToRollback );
if( !sTemp ){
sTemp = 1;
-#if SSDEBUG
- DumpIntoLog( "ModelSnapshot", "Invoked rollback" );
-#endif
- exit( 0 );
+ SSDEBUG("Invoked rollback");
+ exit(EXIT_SUCCESS);
}
#endif
}
+/** The finalize method shuts down the snapshotting system. */
+//Subramanian -- remove this function from the external interface and
+//have us call it internally
+
void finalize(){
-#if !USE_CHECKPOINTING
+#if !USE_MPROTECT_SNAPSHOT
sTheRecord->mbFinalize = true;
#endif
}
projects / c11tester.git / blobdiff