#include <string.h>
#include <errno.h>
#include <sys/wait.h>
-#include <ucontext.h>
#include "hashtable.h"
#include "snapshot.h"
#include "mymemory.h"
#include "common.h"
-
-#define FAILURE(mesg) { model_print("failed in the API: %s with errno relative message: %s\n", mesg, strerror(errno)); exit(EXIT_FAILURE); }
+#include "context.h"
/** PageAlignedAdressUpdate return a page aligned address for the
* address being added as a side effect the numBytes are also changed.
#if USE_MPROTECT_SNAPSHOT
-/* Each snapshotrecord lists the firstbackingpage that must be written to
+/* Each SnapShotRecord lists the firstbackingpage that must be written to
* revert to that snapshot */
struct SnapShotRecord {
unsigned int firstBackingPage;
int sizeInPages; // size of memory region in pages
};
+/** 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));
+}
+
/* Primary struct for snapshotting system */
-struct SnapShot {
+struct mprot_snapshotter {
+ mprot_snapshotter(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions);
+ ~mprot_snapshotter();
+
struct MemoryRegion *regionsToSnapShot; //This pointer references an array of memory regions to snapshot
snapshot_page_t *backingStore; //This pointer references an array of snapshotpage's that form the backing store
void *backingStoreBasePtr; //This pointer references an array of snapshotpage's that form the backing store
unsigned int maxRegions; //Stores the max number of memory regions we support
unsigned int maxBackingPages; //Stores the total number of backing pages
unsigned int maxSnapShots; //Stores the total number of snapshots we allow
+
+ MEMALLOC
};
-static struct SnapShot *snapshotrecord = NULL;
+static struct mprot_snapshotter *mprot_snap = NULL;
-/** 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)
+mprot_snapshotter::mprot_snapshotter(unsigned int backing_pages, unsigned int snapshots, unsigned int regions) :
+ lastSnapShot(0),
+ lastBackingPage(0),
+ lastRegion(0),
+ maxRegions(regions),
+ maxBackingPages(backing_pages),
+ maxSnapShots(snapshots)
{
- return (void *)(((uintptr_t)addr) & ~(PAGESIZE - 1));
+ regionsToSnapShot = (struct MemoryRegion *)model_malloc(sizeof(struct MemoryRegion) * regions);
+ backingStoreBasePtr = (void *)model_malloc(sizeof(snapshot_page_t) * (backing_pages + 1));
+ //Page align the backingstorepages
+ backingStore = (snapshot_page_t *)PageAlignAddressUpward(backingStoreBasePtr);
+ backingRecords = (struct BackingPageRecord *)model_malloc(sizeof(struct BackingPageRecord) * backing_pages);
+ snapShots = (struct SnapShotRecord *)model_malloc(sizeof(struct SnapShotRecord) * snapshots);
}
-/** The initSnapShotRecord method initialized the snapshotting data
- * structures for the mprotect based snapshot.
- */
-static void initSnapShotRecord(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions)
+mprot_snapshotter::~mprot_snapshotter()
{
- snapshotrecord = (struct SnapShot *)model_malloc(sizeof(struct SnapShot));
- snapshotrecord->regionsToSnapShot = (struct MemoryRegion *)model_malloc(sizeof(struct MemoryRegion) * nummemoryregions);
- snapshotrecord->backingStoreBasePtr = (void *)model_malloc(sizeof(snapshot_page_t) * (numbackingpages + 1));
- //Page align the backingstorepages
- snapshotrecord->backingStore = (snapshot_page_t *)PageAlignAddressUpward(snapshotrecord->backingStoreBasePtr);
- snapshotrecord->backingRecords = (struct BackingPageRecord *)model_malloc(sizeof(struct BackingPageRecord) * numbackingpages);
- snapshotrecord->snapShots = (struct SnapShotRecord *)model_malloc(sizeof(struct SnapShotRecord) * numsnapshots);
- snapshotrecord->lastSnapShot = 0;
- snapshotrecord->lastBackingPage = 0;
- snapshotrecord->lastRegion = 0;
- snapshotrecord->maxRegions = nummemoryregions;
- snapshotrecord->maxBackingPages = numbackingpages;
- snapshotrecord->maxSnapShots = numsnapshots;
+ model_free(regionsToSnapShot);
+ model_free(backingStoreBasePtr);
+ model_free(backingRecords);
+ model_free(snapShots);
}
-/** HandlePF is the page fault handler for mprotect based snapshotting
+/** mprot_handle_pf is the page fault handler for mprotect based snapshotting
* algorithm.
*/
-static void HandlePF(int sig, siginfo_t *si, void *unused)
+static void mprot_handle_pf(int sig, siginfo_t *si, void *unused)
{
if (si->si_code == SEGV_MAPERR) {
model_print("Real Fault at %p\n", si->si_addr);
}
void* addr = ReturnPageAlignedAddress(si->si_addr);
- unsigned int backingpage = snapshotrecord->lastBackingPage++; //Could run out of pages...
- if (backingpage == snapshotrecord->maxBackingPages) {
+ unsigned int backingpage = mprot_snap->lastBackingPage++; //Could run out of pages...
+ if (backingpage == mprot_snap->maxBackingPages) {
model_print("Out of backing pages at %p\n", si->si_addr);
exit(EXIT_FAILURE);
}
//copy page
- memcpy(&(snapshotrecord->backingStore[backingpage]), addr, sizeof(snapshot_page_t));
+ memcpy(&(mprot_snap->backingStore[backingpage]), addr, sizeof(snapshot_page_t));
//remember where to copy page back to
- snapshotrecord->backingRecords[backingpage].basePtrOfPage = addr;
+ mprot_snap->backingRecords[backingpage].basePtrOfPage = addr;
//set protection to read/write
if (mprotect(addr, sizeof(snapshot_page_t), PROT_READ | PROT_WRITE)) {
perror("mprotect");
struct sigaction sa;
sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART | SA_ONSTACK;
sigemptyset(&sa.sa_mask);
- sa.sa_sigaction = HandlePF;
+ sa.sa_sigaction = mprot_handle_pf;
#ifdef MAC
if (sigaction(SIGBUS, &sa, NULL) == -1) {
model_print("SIGACTION CANNOT BE INSTALLED\n");
exit(EXIT_FAILURE);
}
- initSnapShotRecord(numbackingpages, numsnapshots, nummemoryregions);
+ mprot_snap = new mprot_snapshotter(numbackingpages, numsnapshots, nummemoryregions);
- // EVIL HACK: We need to make sure that calls into the HandlePF method don't cause dynamic links
+ // EVIL HACK: We need to make sure that calls into the mprot_handle_pf 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
+ mprot_handle_pf(SIGSEGV, &si, NULL);
+ mprot_snap->lastBackingPage--; //remove the fake page we copied
void *basemySpace = model_malloc((numheappages + 1) * PAGESIZE);
void *pagealignedbase = PageAlignAddressUpward(basemySpace);
user_snapshot_space = create_mspace_with_base(pagealignedbase, numheappages * PAGESIZE, 1);
- addMemoryRegionToSnapShot(pagealignedbase, numheappages);
+ snapshot_add_memory_region(pagealignedbase, numheappages);
void *base_model_snapshot_space = model_malloc((numheappages + 1) * PAGESIZE);
pagealignedbase = PageAlignAddressUpward(base_model_snapshot_space);
model_snapshot_space = create_mspace_with_base(pagealignedbase, numheappages * PAGESIZE, 1);
- addMemoryRegionToSnapShot(pagealignedbase, numheappages);
+ snapshot_add_memory_region(pagealignedbase, numheappages);
entryPoint();
}
static void mprot_add_to_snapshot(void *addr, unsigned int numPages)
{
- unsigned int memoryregion = snapshotrecord->lastRegion++;
- if (memoryregion == snapshotrecord->maxRegions) {
+ unsigned int memoryregion = mprot_snap->lastRegion++;
+ if (memoryregion == mprot_snap->maxRegions) {
model_print("Exceeded supported number of memory regions!\n");
exit(EXIT_FAILURE);
}
- snapshotrecord->regionsToSnapShot[memoryregion].basePtr = addr;
- snapshotrecord->regionsToSnapShot[memoryregion].sizeInPages = numPages;
+ mprot_snap->regionsToSnapShot[memoryregion].basePtr = addr;
+ mprot_snap->regionsToSnapShot[memoryregion].sizeInPages = numPages;
}
static snapshot_id mprot_take_snapshot()
{
- for (unsigned int region = 0; region < snapshotrecord->lastRegion; region++) {
- if (mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages * sizeof(snapshot_page_t), PROT_READ) == -1) {
+ for (unsigned int region = 0; region < mprot_snap->lastRegion; region++) {
+ if (mprotect(mprot_snap->regionsToSnapShot[region].basePtr, mprot_snap->regionsToSnapShot[region].sizeInPages * sizeof(snapshot_page_t), PROT_READ) == -1) {
perror("mprotect");
model_print("Failed to mprotect inside of takeSnapShot\n");
exit(EXIT_FAILURE);
}
}
- unsigned int snapshot = snapshotrecord->lastSnapShot++;
- if (snapshot == snapshotrecord->maxSnapShots) {
+ unsigned int snapshot = mprot_snap->lastSnapShot++;
+ if (snapshot == mprot_snap->maxSnapShots) {
model_print("Out of snapshots\n");
exit(EXIT_FAILURE);
}
- snapshotrecord->snapShots[snapshot].firstBackingPage = snapshotrecord->lastBackingPage;
+ mprot_snap->snapShots[snapshot].firstBackingPage = mprot_snap->lastBackingPage;
return snapshot;
}
static void mprot_roll_back(snapshot_id theID)
{
#if USE_MPROTECT_SNAPSHOT == 2
- if (snapshotrecord->lastSnapShot == (theID + 1)) {
- for (unsigned int page = snapshotrecord->snapShots[theID].firstBackingPage; page < snapshotrecord->lastBackingPage; page++) {
- memcpy(snapshotrecord->backingRecords[page].basePtrOfPage, &snapshotrecord->backingStore[page], sizeof(snapshot_page_t));
+ if (mprot_snap->lastSnapShot == (theID + 1)) {
+ for (unsigned int page = mprot_snap->snapShots[theID].firstBackingPage; page < mprot_snap->lastBackingPage; page++) {
+ memcpy(mprot_snap->backingRecords[page].basePtrOfPage, &mprot_snap->backingStore[page], sizeof(snapshot_page_t));
}
return;
}
#endif
HashTable< void *, bool, uintptr_t, 4, model_malloc, model_calloc, model_free> duplicateMap;
- for (unsigned int region = 0; region < snapshotrecord->lastRegion; region++) {
- if (mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages * sizeof(snapshot_page_t), PROT_READ | PROT_WRITE) == -1) {
+ for (unsigned int region = 0; region < mprot_snap->lastRegion; region++) {
+ if (mprotect(mprot_snap->regionsToSnapShot[region].basePtr, mprot_snap->regionsToSnapShot[region].sizeInPages * sizeof(snapshot_page_t), PROT_READ | PROT_WRITE) == -1) {
perror("mprotect");
model_print("Failed to mprotect inside of takeSnapShot\n");
exit(EXIT_FAILURE);
}
}
- for (unsigned int page = snapshotrecord->snapShots[theID].firstBackingPage; page < snapshotrecord->lastBackingPage; page++) {
- if (!duplicateMap.contains(snapshotrecord->backingRecords[page].basePtrOfPage)) {
- duplicateMap.put(snapshotrecord->backingRecords[page].basePtrOfPage, true);
- memcpy(snapshotrecord->backingRecords[page].basePtrOfPage, &snapshotrecord->backingStore[page], sizeof(snapshot_page_t));
+ for (unsigned int page = mprot_snap->snapShots[theID].firstBackingPage; page < mprot_snap->lastBackingPage; page++) {
+ if (!duplicateMap.contains(mprot_snap->backingRecords[page].basePtrOfPage)) {
+ duplicateMap.put(mprot_snap->backingRecords[page].basePtrOfPage, true);
+ memcpy(mprot_snap->backingRecords[page].basePtrOfPage, &mprot_snap->backingStore[page], sizeof(snapshot_page_t));
}
}
- snapshotrecord->lastSnapShot = theID;
- snapshotrecord->lastBackingPage = snapshotrecord->snapShots[theID].firstBackingPage;
+ mprot_snap->lastSnapShot = theID;
+ mprot_snap->lastBackingPage = mprot_snap->snapShots[theID].firstBackingPage;
mprot_take_snapshot(); //Make sure current snapshot is still good...All later ones are cleared
}
#else /* !USE_MPROTECT_SNAPSHOT */
-#include <ucontext.h>
-
#define SHARED_MEMORY_DEFAULT (100 * ((size_t)1 << 20)) // 100mb for the shared memory
#define STACK_SIZE_DEFAULT (((size_t)1 << 20) * 20) // 20 mb out of the above 100 mb for my stack
-struct SnapShot {
+struct fork_snapshotter {
void *mSharedMemoryBase;
void *mStackBase;
size_t mStackSize;
snapshot_id currSnapShotID;
};
-static struct SnapShot *snapshotrecord = NULL;
+static struct fork_snapshotter *fork_snap = NULL;
/** @statics
* These variables are necessary because the stack is shared region and
{
//step 1. create shared memory.
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");
+ if (memMapBase == MAP_FAILED) {
+ perror("mmap");
+ exit(EXIT_FAILURE);
+ }
//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;
+ fork_snap = (struct fork_snapshotter *)memMapBase;
+ fork_snap->mSharedMemoryBase = (void *)((uintptr_t)memMapBase + sizeof(struct fork_snapshotter));
+ fork_snap->mStackBase = (void *)((uintptr_t)memMapBase + SHARED_MEMORY_DEFAULT);
+ fork_snap->mStackSize = STACK_SIZE_DEFAULT;
+ fork_snap->mIDToRollback = -1;
+ fork_snap->currSnapShotID = 0;
}
/**
*/
mspace create_shared_mspace()
{
- if (!snapshotrecord)
+ if (!fork_snap)
createSharedMemory();
- return create_mspace_with_base((void *)(snapshotrecord->mSharedMemoryBase), SHARED_MEMORY_DEFAULT - sizeof(struct SnapShot), 1);
+ return create_mspace_with_base((void *)(fork_snap->mSharedMemoryBase), SHARED_MEMORY_DEFAULT - sizeof(struct fork_snapshotter), 1);
}
static void fork_snapshot_init(unsigned int numbackingpages,
unsigned int numsnapshots, unsigned int nummemoryregions,
unsigned int numheappages, VoidFuncPtr entryPoint)
{
- if (!snapshotrecord)
+ if (!fork_snap)
createSharedMemory();
void *base_model_snapshot_space = malloc((numheappages + 1) * PAGESIZE);
//step 2 setup the stack context.
ucontext_t newContext;
getcontext(&newContext);
- newContext.uc_stack.ss_sp = snapshotrecord->mStackBase;
+ newContext.uc_stack.ss_sp = fork_snap->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);
+ model_swapcontext(&savedSnapshotContext, &newContext);
/* switch back here when takesnapshot is called */
pid_t forkedID = 0;
- snapshotid = snapshotrecord->currSnapShotID;
+ snapshotid = fork_snap->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) {
- snapshotrecord->currSnapShotID = snapshotid + 1;
+ fork_snap->currSnapShotID = snapshotid + 1;
forkedID = fork();
if (0 == forkedID) {
/* If the rollback bool is set, switch to the context we need to
return to during a rollback. */
if (rollback) {
- setcontext(&(snapshotrecord->mContextToRollback));
+ setcontext(&(fork_snap->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;
-
- DEBUG("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);
+ DEBUG("parent PID: %d, child PID: %d, snapshot ID: %d\n",
+ getpid(), forkedID, snapshotid);
+
+ while (waitpid(forkedID, NULL, 0) < 0) {
+ /* waitpid() may be interrupted */
+ if (errno != EINTR) {
+ perror("waitpid");
+ exit(EXIT_FAILURE);
+ }
+ }
- if (snapshotrecord->mIDToRollback != snapshotid) {
+ if (fork_snap->mIDToRollback != snapshotid)
exit(EXIT_SUCCESS);
- }
rollback = true;
}
}
static snapshot_id fork_take_snapshot()
{
- swapcontext(&savedUserSnapshotContext, &savedSnapshotContext);
+ model_swapcontext(&savedUserSnapshotContext, &savedSnapshotContext);
DEBUG("TAKESNAPSHOT RETURN\n");
return snapshotid;
}
static void fork_roll_back(snapshot_id theID)
{
- snapshotrecord->mIDToRollback = theID;
+ fork_snap->mIDToRollback = theID;
volatile int sTemp = 0;
- getcontext(&snapshotrecord->mContextToRollback);
+ getcontext(&fork_snap->mContextToRollback);
/*
* This is used to quit the process on rollback, so that the process
* which needs to rollback can quit allowing the process whose
/*
* This fix obviates the need for a finalize call. hence less dependences for model-checker....
*/
- snapshotrecord->mIDToRollback = -1;
+ fork_snap->mIDToRollback = -1;
}
#endif /* !USE_MPROTECT_SNAPSHOT */
-/** The initSnapshotLibrary function initializes the snapshot library.
- * @param entryPoint the function that should run the program.
+/**
+ * @brief Initializes the snapshot system
+ * @param entryPoint the function that should run the program.
*/
-void initSnapshotLibrary(unsigned int numbackingpages,
+void snapshot_system_init(unsigned int numbackingpages,
unsigned int numsnapshots, unsigned int nummemoryregions,
unsigned int numheappages, VoidFuncPtr entryPoint)
{
#endif
}
-/** The addMemoryRegionToSnapShot function assumes that addr is page aligned. */
-void addMemoryRegionToSnapShot(void *addr, unsigned int numPages)
+/** Assumes that addr is page aligned. */
+void snapshot_add_memory_region(void *addr, unsigned int numPages)
{
#if USE_MPROTECT_SNAPSHOT
mprot_add_to_snapshot(addr, numPages);
#endif
}
-/** The takeSnapshot function takes a snapshot.
+/** Takes a snapshot of memory.
* @return The snapshot identifier.
*/
-snapshot_id takeSnapshot()
+snapshot_id take_snapshot()
{
#if USE_MPROTECT_SNAPSHOT
return mprot_take_snapshot();
#endif
}
-/** The rollBack function rollback to the given snapshot identifier.
+/** Rolls the memory state back to the given snapshot identifier.
* @param theID is the snapshot identifier to rollback to.
*/
-void rollBack(snapshot_id theID)
+void snapshot_roll_back(snapshot_id theID)
{
#if USE_MPROTECT_SNAPSHOT
mprot_roll_back(theID);
projects / c11tester.git / blobdiff