wow, this is a nasty bug...

[model-checker.git] / snapshot.cc

diff --git a/snapshot.cc b/snapshot.cc
index 83d22b4f5939b31ec7689177aed381b057966697..7105d2c6a170905bc3dc4250ea3c3b365381db01 100644 (file)
--- 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;
@@ -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 ){
@@ -139,7 +152,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
        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();