#endif
/* extern declaration definition */
-#if USE_MPROTECT_SNAPSHOT
struct SnapShot * snapshotrecord = NULL;
-#else
-struct Snapshot * sTheRecord = NULL;
-#endif
#if !USE_MPROTECT_SNAPSHOT
/** @statics
}
#endif //nothing to handle for non snapshotting case.
-void createSharedLibrary(){
#if !USE_MPROTECT_SNAPSHOT
+void createSharedMemory(){
//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, 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 );
+ void * memMapBase = mmap( 0, SHARED_MEMORY_DEFAULT + STACK_SIZE_DEFAULT, PROT_READ | PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0 );
if( MAP_FAILED == memMapBase )
FAILURE("mmap");
- sTheRecord = ( struct Snapshot * )memMapBase;
- 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;
-#endif
+
+ //Setup snapshot record at top of free region
+ snapshotrecord = ( struct SnapShot * )memMapBase;
+ snapshotrecord->mSharedMemoryBase = (void *)((uintptr_t)memMapBase + sizeof(struct SnapShot));
+ snapshotrecord->mStackBase = (void *)((uintptr_t)memMapBase + SHARED_MEMORY_DEFAULT);
+ snapshotrecord->mStackSize = STACK_SIZE_DEFAULT;
+ snapshotrecord->mIDToRollback = -1;
+ snapshotrecord->currSnapShotID = 0;
}
+#endif
+
/** The initSnapShotLibrary function initializes the Snapshot library.
* @param entryPoint the function that should run the program.
*/
+#if USE_MPROTECT_SNAPSHOT
+
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);
mySpace = create_mspace_with_base(pagealignedbase, numheappages*PAGESIZE, 1 );
addMemoryRegionToSnapShot(pagealignedbase, numheappages);
entryPoint();
+}
#else
-
+void initSnapShotLibrary(unsigned int numbackingpages,
+ unsigned int numsnapshots, unsigned int nummemoryregions,
+ unsigned int numheappages, VoidFuncPtr entryPoint) {
basemySpace=system_malloc((numheappages+1)*PAGESIZE);
void * pagealignedbase=PageAlignAddressUpward(basemySpace);
mySpace = create_mspace_with_base(pagealignedbase, numheappages*PAGESIZE, 1 );
- createSharedLibrary();
+ if (!snapshotrecord)
+ createSharedMemory();
//step 2 setup the stack context.
ucontext_t newContext;
getcontext( &newContext );
- newContext.uc_stack.ss_sp = sTheRecord->mStackBase;
+ newContext.uc_stack.ss_sp = snapshotrecord->mStackBase;
newContext.uc_stack.ss_size = STACK_SIZE_DEFAULT;
makecontext( &newContext, entryPoint, 0 );
/* switch to a new entryPoint context, on a new stack */
/* switch back here when takesnapshot is called */
pid_t forkedID = 0;
- snapshotid = sTheRecord->currSnapShotID;
- bool swapContext = false;
+ snapshotid = snapshotrecord->currSnapShotID;
+ /* This bool indicates that the current process's snapshotid is same
+ as the id to which the rollback needs to occur */
+
+ bool rollback = false;
while( true ){
- sTheRecord->currSnapShotID=snapshotid+1;
+ snapshotrecord->currSnapShotID=snapshotid+1;
forkedID = fork();
+
if( 0 == forkedID ){
- ucontext_t currentContext;
- /*If the rollback bool is set{ see below }, switch to the context we need to return to during a rollback*/
- if( swapContext )
- swapcontext( ¤tContext, &( sTheRecord->mContextToRollback ) );
- else{
- /*Child process which is forked as a result of takesnapshot call should switch back to the takesnapshot context*/
- swapcontext( ¤tContext, &savedUserSnapshotContext );
+ /* If the rollback bool is set, switch to the context we need to
+ return to during a rollback. */
+ if( rollback) {
+ setcontext( &( snapshotrecord->mContextToRollback ) );
+ } else {
+ /*Child process which is forked as a result of takesnapshot
+ call should switch back to the takesnapshot context*/
+ setcontext( &savedUserSnapshotContext );
}
} else {
int status;
int retVal;
- SSDEBUG("The process id of child is %d and the process id of this process is %d and snapshot id is %d",
+ SSDEBUG("The process id of child is %d and the process id of this process is %d and snapshot id is %d\n",
forkedID, getpid(), snapshotid );
do {
retVal=waitpid( forkedID, &status, 0 );
} while( -1 == retVal && errno == EINTR );
- if( sTheRecord->mIDToRollback != snapshotid )
+ if( snapshotrecord->mIDToRollback != snapshotid ) {
exit(EXIT_SUCCESS);
- else{
- /*This bool indicates that the current process's snapshotid is same as the id to which the rollback needs to occur*/
- swapContext = true;
}
+ rollback = true;
}
}
-
-#endif
}
+#endif
/** The addMemoryRegionToSnapShot function assumes that addr is page aligned.
*/
return snapshot;
#else
swapcontext( &savedUserSnapshotContext, &savedSnapshotContext );
+ SSDEBUG("TAKESNAPSHOT RETURN\n");
return snapshotid;
#endif
}
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 );
+ snapshotrecord->mIDToRollback = theID;
+ volatile int sTemp = 0;
+ getcontext( &snapshotrecord->mContextToRollback );
/*
- * This is used to quit the process on rollback, so that
- * the process which needs to rollback can quit allowing the process whose snapshotid matches the rollbackid to switch to
- * this context and continue....
- */
+ * This is used to quit the process on rollback, so that the process
+ * which needs to rollback can quit allowing the process whose
+ * snapshotid matches the rollbackid to switch to this context and
+ * continue....
+ */
if( !sTemp ){
sTemp = 1;
- SSDEBUG("Invoked rollback");
+ SSDEBUG("Invoked rollback\n");
exit(EXIT_SUCCESS);
}
- /*
- * This fix obviates the need for a finalize call. hence less dependences for model-checker....
- *
- */
- sTheRecord->mIDToRollback = -1;
+ /*
+ * This fix obviates the need for a finalize call. hence less dependences for model-checker....
+ *
+ */
+ snapshotrecord->mIDToRollback = -1;
#endif
}
projects / model-checker.git / blobdiff