fix bug...this is another evil one...

[c11tester.git] / snapshot.cc

diff --git a/snapshot.cc b/snapshot.cc
index cdc2528da14a7a1204b5fd9011a3aaf4c07784e7..e8fdadba28839df18728b42ab7194c46ec01989c 100644 (file)
--- a/snapshot.cc
+++ b/snapshot.cc
@@ -4,7 +4,6 @@
 #include <signal.h>
 #include <stdlib.h>
 #include <map>
-#include <set>
 #include <cstring>
 #include <cstdio>
 #include "snapshot.h"
@@ -20,7 +19,7 @@
 
 //extern declaration definition
 #define FAILURE(mesg) { printf("failed in the API: %s with errno relative message: %s\n", mesg, strerror( errno ) ); exit( -1 ); }
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
 struct SnapShot * snapshotrecord = NULL;
 struct Snapshot_t * sTheRecord = NULL;
 #else
@@ -38,13 +37,13 @@ void DumpIntoLog( const char * filename, const char * message ){
        myFile = NULL;
 #endif
 }
-#if !USE_CHECKPOINTING
+#if !USE_MPROTECT_SNAPSHOT
 static ucontext_t savedSnapshotContext;
 static ucontext_t savedUserSnapshotContext;
-static int snapshotid = 0;
+static snapshot_id snapshotid = 0;
 #endif
 /* Initialize snapshot data structure */
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_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);
@@ -63,7 +62,7 @@ void initSnapShotRecord(unsigned int numbackingpages, unsigned int numsnapshots,
 #endif //nothing to initialize for the fork based snapshotting.
 
 void HandlePF( int sig, siginfo_t *si, void * unused){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
        if( si->si_code == SEGV_MAPERR ){
                printf("Real Fault at %p\n", si->si_addr);
                exit( EXIT_FAILURE );
@@ -102,7 +101,7 @@ void * PageAlignAddressUpward(void * addr) {
 extern "C" {
 #endif
        void createSharedLibrary(){
-#if !USE_CHECKPOINTING
+#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.
@@ -121,8 +120,10 @@ extern "C" {
 #ifdef __cplusplus
 }
 #endif
-void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots, unsigned int nummemoryregions, unsigned int numheappages, MyFuncPtr entryPoint){
-#if USE_CHECKPOINTING
+void initSnapShotLibrary(unsigned int numbackingpages,
+               unsigned int numsnapshots, unsigned int nummemoryregions,
+               unsigned int numheappages, VoidFuncPtr entryPoint) {
+#if USE_MPROTECT_SNAPSHOT
        /* Setup a stack for our signal handler....  */
        stack_t ss;
        ss.ss_sp = MYMALLOC(SIGSTACKSIZE);
@@ -140,6 +141,15 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
        }
        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;
+       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 );
@@ -215,7 +225,7 @@ void initSnapShotLibrary(unsigned int numbackingpages, unsigned int numsnapshots
 }
 /* This function assumes that addr is page aligned */
 void addMemoryRegionToSnapShot( void * addr, unsigned int numPages) {
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
        unsigned int memoryregion=snapshotrecord->lastRegion++;
        if (memoryregion==snapshotrecord->maxRegions) {
                printf("Exceeded supported number of memory regions!\n");
@@ -228,7 +238,7 @@ void addMemoryRegionToSnapShot( void * addr, unsigned int numPages) {
 }
 //take snapshot
 snapshot_id takeSnapshot( ){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
        for(unsigned int region=0; region<snapshotrecord->lastRegion;region++) {
                if( mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages*sizeof(struct SnapShotPage), PROT_READ ) == -1 ){
                        perror("mprotect");
@@ -250,7 +260,7 @@ snapshot_id takeSnapshot( ){
 #endif
 }
 void rollBack( snapshot_id theID ){
-#if USE_CHECKPOINTING
+#if USE_MPROTECT_SNAPSHOT
        std::map< void *, bool, std::less< void * >, MyAlloc< std::pair< const void *, bool > > > duplicateMap;
        for(unsigned int region=0; region<snapshotrecord->lastRegion;region++) {
                if( mprotect(snapshotrecord->regionsToSnapShot[region].basePtr, snapshotrecord->regionsToSnapShot[region].sizeInPages*sizeof(struct SnapShotPage), PROT_READ | PROT_WRITE ) == -1 ){
@@ -289,7 +299,7 @@ void rollBack( snapshot_id theID ){
 }
 
 void finalize(){
-#if !USE_CHECKPOINTING
+#if !USE_MPROTECT_SNAPSHOT
        sTheRecord->mbFinalize = true;
 #endif
 }