#include "hashtable.h"
#include "snapshot.h"
-#include "snapshotimp.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); }
-#ifdef CONFIG_SSDEBUG
-#define SSDEBUG model_print
-#else
-#define SSDEBUG(...) do { } while (0)
-#endif
-
-/* extern declaration definition */
-struct SnapShot *snapshotrecord = NULL;
-
/** PageAlignedAdressUpdate return a page aligned address for the
* address being added as a side effect the numBytes are also changed.
*/
return (void *)((((uintptr_t)addr) + PAGESIZE - 1) & ~(PAGESIZE - 1));
}
-#if !USE_MPROTECT_SNAPSHOT
-/** @statics
-* These variables are necessary because the stack is shared region and
-* there exists a race between all processes executing the same function.
-* To avoid the problem above, we require variables allocated in 'safe' regions.
-* The bug was actually observed with the forkID, these variables below are
-* used to indicate the various contexts to which to switch to.
-*
-* @savedSnapshotContext: contains the point to which takesnapshot() call should switch to.
-* @savedUserSnapshotContext: contains the point to which the process whose snapshotid is equal to the rollbackid should switch to
-* @snapshotid: it is a running counter for the various forked processes snapshotid. it is incremented and set in a persistently shared record
-*/
-static ucontext_t savedSnapshotContext;
-static ucontext_t savedUserSnapshotContext;
-static snapshot_id snapshotid = 0;
+#if USE_MPROTECT_SNAPSHOT
-#else /* USE_MPROTECT_SNAPSHOT */
+/* Each snapshotrecord lists the firstbackingpage that must be written to
+ * revert to that snapshot */
+struct SnapShotRecord {
+ unsigned int firstBackingPage;
+};
+
+/** @brief Backing store page */
+typedef unsigned char snapshot_page_t[PAGESIZE];
+
+/* List the base address of the corresponding page in the backing store so we
+ * know where to copy it to */
+struct BackingPageRecord {
+ void *basePtrOfPage;
+};
+
+/* Struct for each memory region */
+struct MemoryRegion {
+ void *basePtr; // base of memory region
+ int sizeInPages; // size of memory region in pages
+};
+
+/* Primary struct for snapshotting system */
+struct SnapShot {
+ 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
+ struct BackingPageRecord *backingRecords; //This pointer references an array of backingpagerecord's (same number of elements as backingstore
+ struct SnapShotRecord *snapShots; //This pointer references the snapshot array
+
+ unsigned int lastSnapShot; //Stores the next snapshot record we should use
+ unsigned int lastBackingPage; //Stores the next backingpage we should use
+ unsigned int lastRegion; //Stores the next memory region to be used
+
+ 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
+};
+
+static struct SnapShot *snapshotrecord = NULL;
/** ReturnPageAlignedAddress returns a page aligned address for the
* address being added as a side effect the numBytes are also changed.
// Handle error by quitting?
}
}
-#endif /* USE_MPROTECT_SNAPSHOT */
-
-#if !USE_MPROTECT_SNAPSHOT
-void createSharedMemory()
-{
- //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");
-
- //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)
entryPoint();
}
-#else
+
+/** The addMemoryRegionToSnapShot function assumes that addr is page aligned. */
+void addMemoryRegionToSnapShot(void *addr, unsigned int numPages)
+{
+ unsigned int memoryregion = snapshotrecord->lastRegion++;
+ if (memoryregion == snapshotrecord->maxRegions) {
+ model_print("Exceeded supported number of memory regions!\n");
+ exit(EXIT_FAILURE);
+ }
+
+ snapshotrecord->regionsToSnapShot[memoryregion].basePtr = addr;
+ snapshotrecord->regionsToSnapShot[memoryregion].sizeInPages = numPages;
+}
+
+/** The takeSnapshot function takes a snapshot.
+ * @return The snapshot identifier.
+ */
+snapshot_id takeSnapshot()
+{
+ 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) {
+ perror("mprotect");
+ model_print("Failed to mprotect inside of takeSnapShot\n");
+ exit(EXIT_FAILURE);
+ }
+ }
+ unsigned int snapshot = snapshotrecord->lastSnapShot++;
+ if (snapshot == snapshotrecord->maxSnapShots) {
+ model_print("Out of snapshots\n");
+ exit(EXIT_FAILURE);
+ }
+ snapshotrecord->snapShots[snapshot].firstBackingPage = snapshotrecord->lastBackingPage;
+
+ return snapshot;
+}
+
+/** 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 == 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));
+ }
+ 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) {
+ 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));
+ }
+ }
+ snapshotrecord->lastSnapShot = theID;
+ snapshotrecord->lastBackingPage = snapshotrecord->snapShots[theID].firstBackingPage;
+ takeSnapshot(); //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 {
+ void *mSharedMemoryBase;
+ void *mStackBase;
+ size_t mStackSize;
+ volatile snapshot_id mIDToRollback;
+ ucontext_t mContextToRollback;
+ snapshot_id currSnapShotID;
+};
+
+static struct SnapShot *snapshotrecord = NULL;
+
+/** @statics
+* These variables are necessary because the stack is shared region and
+* there exists a race between all processes executing the same function.
+* To avoid the problem above, we require variables allocated in 'safe' regions.
+* The bug was actually observed with the forkID, these variables below are
+* used to indicate the various contexts to which to switch to.
+*
+* @savedSnapshotContext: contains the point to which takesnapshot() call should switch to.
+* @savedUserSnapshotContext: contains the point to which the process whose snapshotid is equal to the rollbackid should switch to
+* @snapshotid: it is a running counter for the various forked processes snapshotid. it is incremented and set in a persistently shared record
+*/
+static ucontext_t savedSnapshotContext;
+static ucontext_t savedUserSnapshotContext;
+static snapshot_id snapshotid = 0;
+
+static void createSharedMemory()
+{
+ //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");
+
+ //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;
+}
+
+/**
+ * Create a new mspace pointer for the non-snapshotting (i.e., inter-process
+ * shared) memory region. Only for fork-based snapshotting.
+ *
+ * @return The shared memory mspace
+ */
+mspace create_shared_mspace()
+{
+ if (!snapshotrecord)
+ createSharedMemory();
+ return create_mspace_with_base((void *)(snapshotrecord->mSharedMemoryBase), SHARED_MEMORY_DEFAULT - sizeof(struct SnapShot), 1);
+}
+
void initSnapshotLibrary(unsigned int numbackingpages,
unsigned int numsnapshots, unsigned int nummemoryregions,
unsigned int numheappages, VoidFuncPtr entryPoint)
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\n",
+ 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 {
}
}
}
-#endif
-/** 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) {
- model_print("Exceeded supported number of memory regions!\n");
- exit(EXIT_FAILURE);
- }
-
- snapshotrecord->regionsToSnapShot[memoryregion].basePtr = addr;
- snapshotrecord->regionsToSnapShot[memoryregion].sizeInPages = numPages;
-#endif //NOT REQUIRED IN THE CASE OF FORK BASED SNAPSHOTS.
+ /* not needed for fork-based snapshotting */
}
-/** The takeSnapshot function takes a snapshot.
- * @return The snapshot identifier.
- */
snapshot_id takeSnapshot()
{
-#if USE_MPROTECT_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) {
- perror("mprotect");
- model_print("Failed to mprotect inside of takeSnapShot\n");
- exit(EXIT_FAILURE);
- }
- }
- unsigned int snapshot = snapshotrecord->lastSnapShot++;
- if (snapshot == snapshotrecord->maxSnapShots) {
- model_print("Out of snapshots\n");
- exit(EXIT_FAILURE);
- }
- snapshotrecord->snapShots[snapshot].firstBackingPage = snapshotrecord->lastBackingPage;
-
- return snapshot;
-#else
swapcontext(&savedUserSnapshotContext, &savedSnapshotContext);
- SSDEBUG("TAKESNAPSHOT RETURN\n");
+ DEBUG("TAKESNAPSHOT RETURN\n");
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 == 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));
- }
- return;
- }
-#endif
-
-#if USE_MPROTECT_SNAPSHOT
- 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) {
- 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));
- }
- }
- snapshotrecord->lastSnapShot = theID;
- snapshotrecord->lastBackingPage = snapshotrecord->snapShots[theID].firstBackingPage;
- takeSnapshot(); //Make sure current snapshot is still good...All later ones are cleared
-#else
snapshotrecord->mIDToRollback = theID;
volatile int sTemp = 0;
getcontext(&snapshotrecord->mContextToRollback);
*/
if (!sTemp) {
sTemp = 1;
- SSDEBUG("Invoked rollback\n");
+ DEBUG("Invoked rollback\n");
exit(EXIT_SUCCESS);
}
/*
* This fix obviates the need for a finalize call. hence less dependences for model-checker....
*/
snapshotrecord->mIDToRollback = -1;
-#endif
}
+
+#endif /* !USE_MPROTECT_SNAPSHOT */
projects / model-checker.git / blobdiff