model: build up 'may_read_from' set

[c11tester.git] / snapshot.cc

diff --git a/snapshot.cc b/snapshot.cc
index db597a2a0f7fa5dd8e43aa67129cfa9341cc563a..a50835d1cca27ecd2c28aac29e798791dce3f69c 100644 (file)
--- a/snapshot.cc
+++ b/snapshot.cc
@@ -104,15 +104,19 @@ static void HandlePF( int sig, siginfo_t *si, void * unused){
 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;
@@ -174,19 +178,13 @@ void initSnapShotLibrary(unsigned int numbackingpages,
        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 = &currentContext;
-               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...