X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=snapshot.cc;h=99b9d7958753d49b77513e279ff40bd4196ad178;hp=7cea7d6191ca457b5c7b98cd1e45dc2c15596e22;hb=7d2149ffbbc1a3514838d721a71bb0d4c81054b3;hpb=ebebe8c4d739b4facc4d4c294dfb90367eb43cc8 diff --git a/snapshot.cc b/snapshot.cc index 7cea7d61..99b9d795 100644 --- a/snapshot.cc +++ b/snapshot.cc @@ -17,33 +17,46 @@ #include #include -//extern declaration definition -#define FAILURE(mesg) { printf("failed in the API: %s with errno relative message: %s\n", mesg, strerror( errno ) ); exit( -1 ); } +#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 +#define SSDEBUG(...) do { } while (0) +#endif + +/* extern declaration definition */ #if USE_MPROTECT_SNAPSHOT struct SnapShot * snapshotrecord = NULL; -struct Snapshot_t * sTheRecord = NULL; #else -struct Snapshot_t * sTheRecord = NULL; +struct Snapshot * sTheRecord = 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+" ); - fprintf( myFile, "the message %s: the process id %d\n", message, thePID ); - fflush( myFile ); - fclose( myFile ); - myFile = NULL; -#endif -} + #if !USE_MPROTECT_SNAPSHOT static ucontext_t savedSnapshotContext; static ucontext_t savedUserSnapshotContext; static snapshot_id snapshotid = 0; #endif -/* Initialize snapshot data structure */ + +/** 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); @@ -61,6 +74,10 @@ void initSnapShotRecord(unsigned int numbackingpages, unsigned int numsnapshots, } #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_MPROTECT_SNAPSHOT if( si->si_code == SEGV_MAPERR ){ @@ -68,6 +85,7 @@ void HandlePF( int sig, siginfo_t *si, void * unused){ 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 %p\n", si->si_addr); @@ -86,40 +104,28 @@ void HandlePF( int sig, siginfo_t *si, void * unused){ #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)); -} - -//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 - void createSharedLibrary(){ +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_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; + //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 + +/** 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) { @@ -135,27 +141,39 @@ void initSnapShotLibrary(unsigned int numbackingpages, 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); + // 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(); //step 2 setup the stack context. @@ -195,17 +213,16 @@ void initSnapShotLibrary(unsigned int numbackingpages, } 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 + + 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; } @@ -214,33 +231,39 @@ void initSnapShotLibrary(unsigned int numbackingpages, #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_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_MPROTECT_SNAPSHOT for(unsigned int region=0; regionlastRegion;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; @@ -250,6 +273,11 @@ snapshot_id takeSnapshot( ){ 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_MPROTECT_SNAPSHOT std::map< void *, bool, std::less< void * >, MyAlloc< std::pair< const void *, bool > > > duplicateMap; @@ -257,7 +285,7 @@ void rollBack( snapshot_id theID ){ 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; pagelastBackingPage; page++) { @@ -281,14 +309,16 @@ void rollBack( snapshot_id theID ){ 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_MPROTECT_SNAPSHOT sTheRecord->mbFinalize = true;