snapshotrecord->maxBackingPages=numbackingpages;
snapshotrecord->maxSnapShots=numsnapshots;
}
-#endif //nothing to initialize for the fork based snapshotting.
/** HandlePF is the page fault handler for mprotect based snapshotting
* algorithm.
*/
static void HandlePF( int sig, siginfo_t *si, void * unused){
-#if USE_MPROTECT_SNAPSHOT
if( si->si_code == SEGV_MAPERR ){
printf("Real Fault at %p\n", si->si_addr);
exit( EXIT_FAILURE );
perror("mprotect");
// Handle error by quitting?
}
-#endif //nothing to handle for non snapshotting case.
}
+#endif //nothing to handle for non snapshotting case.
void createSharedLibrary(){
#if !USE_MPROTECT_SNAPSHOT
//step 1. create shared memory.
- if( sTheRecord ) return;
+ 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");
+ if ( -1 == fd )
+ FAILURE("shm_open");
+ if ( -1 == ftruncate( fd, SHARED_MEMORY_DEFAULT + STACK_SIZE_DEFAULT ) )
+ FAILURE( "ftruncate" );
+ void * memMapBase = mmap( 0, SHARED_MEMORY_DEFAULT + 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->mSharedMemoryBase = (void *)((uintptr_t)memMapBase + sizeof(struct Snapshot));
+ sTheRecord->mStackBase = (void *)((uintptr_t)memMapBase + SHARED_MEMORY_DEFAULT);
sTheRecord->mStackSize = STACK_SIZE_DEFAULT;
sTheRecord->mIDToRollback = -1;
sTheRecord->currSnapShotID = 0;
createSharedLibrary();
//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 );
- }
+ ucontext_t newContext;
+ getcontext( &newContext );
+ newContext.uc_stack.ss_sp = sTheRecord->mStackBase;
+ newContext.uc_stack.ss_size = STACK_SIZE_DEFAULT;
+ makecontext( &newContext, entryPoint, 0 );
+ /* switch to a new entryPoint context, on a new stack */
+ swapcontext(&savedSnapshotContext, &newContext);
//add the code to take a snapshot here...
//to return to user process, do a second swapcontext...