#include "snapshotimp.h"
#include <stdio.h>
#include <dlfcn.h>
+#include <unistd.h>
+#include <cstring>
+#define REQUESTS_BEFORE_ALLOC 1024
+size_t allocatedReqs[ REQUESTS_BEFORE_ALLOC ] = { 0 };
+int nextRequest = 0;
+int howManyFreed = 0;
#if !USE_MPROTECT_SNAPSHOT
static mspace sStaticSpace = NULL;
#endif
+/** Non-snapshotting malloc for our use. */
+
void *MYMALLOC(size_t size) {
#if USE_MPROTECT_SNAPSHOT
static void *(*mallocp)(size_t size);
mallocp = ( void * ( * )( size_t ) )dlsym(RTLD_NEXT, "malloc");
if ((error = dlerror()) != NULL) {
fputs(error, stderr);
- exit(1);
+ exit(EXIT_FAILURE);
}
}
ptr = mallocp(size);
createSharedLibrary();
}
if( NULL == sStaticSpace )
- sStaticSpace = create_mspace_with_base( ( void * )( sTheRecord->mSharedMemoryBase ), SHARED_MEMORY_DEFAULT -sizeof( struct Snapshot_t ), 1 );
+ sStaticSpace = create_mspace_with_base( ( void * )( sTheRecord->mSharedMemoryBase ), SHARED_MEMORY_DEFAULT -sizeof( struct Snapshot ), 1 );
return mspace_malloc( sStaticSpace, size );
#endif
}
mallocp = ( void * ( * )( size_t ) )dlsym(RTLD_NEXT, "malloc");
if ((error = dlerror()) != NULL) {
fputs(error, stderr);
- exit(1);
+ exit(EXIT_FAILURE);
}
}
ptr = mallocp(size);
freep = ( void ( * )( void * ) )dlsym(RTLD_NEXT, "free");
if ((error = dlerror()) != NULL) {
fputs(error, stderr);
- exit(1);
+ exit(EXIT_FAILURE);
}
}
freep(ptr);
}
+
+/** Non-snapshotting free for our use. */
void MYFREE(void *ptr) {
#if USE_MPROTECT_SNAPSHOT
static void (*freep)(void *);
freep = ( void ( * )( void * ) )dlsym(RTLD_NEXT, "free");
if ((error = dlerror()) != NULL) {
fputs(error, stderr);
- exit(1);
+ exit(EXIT_FAILURE);
}
}
freep(ptr);
mspace_free( sStaticSpace, ptr );
#endif
}
+
+
+/** This global references the mspace for the snapshotting heap */
mspace mySpace = NULL;
+
+/** This global references the unaligned memory address that was malloced for the snapshotting heap */
void * basemySpace = NULL;
+/** Adding the fix for not able to allocate through a reimplemented calloc at the beginning before instantiating our allocator
+A bit circumspect about adding an sbrk. linux docs say to avoid using it... */
+
+void * HandleEarlyAllocationRequest( size_t sz ){
+ if( 0 == mySpace ){
+ void * returnAddress = sbrk( sz );
+ if( nextRequest >= REQUESTS_BEFORE_ALLOC ){
+ exit( EXIT_FAILURE );
+ }
+ allocatedReqs[ nextRequest++ ] = ( size_t )returnAddress;
+ return returnAddress;
+ }
+ return NULL;
+}
+
+/** The fact that I am not expecting more than a handful requests is implicit in my not using a binary search here*/
+
+bool DontFree( void * ptr ){
+ if( howManyFreed == nextRequest ) return false; //a minor optimization to reduce the number of instructions executed on each free call....
+ if( NULL == ptr ) return true;
+ for( int i = nextRequest - 1; i >= 0; --i ){
+ if( allocatedReqs[ i ] == ( size_t )ptr ) {
+ ++howManyFreed;
+ return true;
+ }
+ }
+ return false;
+}
+
+/** Snapshotting malloc implementation for user programs. */
+
void *malloc( size_t size ) {
+ void * earlyReq = HandleEarlyAllocationRequest( size );
+ if( earlyReq ) return earlyReq;
return mspace_malloc( mySpace, size );
}
+/** Snapshotting free implementation for user programs. */
+
void free( void * ptr ){
+ if( DontFree( ptr ) ) return;
mspace_free( mySpace, ptr );
}
+/** Snapshotting realloc implementation for user programs. */
+
void *realloc( void *ptr, size_t size ){
return mspace_realloc( mySpace, ptr, size );
}
+/** Snapshotting calloc implementation for user programs. */
+
+void * calloc( size_t num, size_t size ){
+ void * earlyReq = HandleEarlyAllocationRequest( size * num );
+ if( earlyReq ) {
+ std::memset( earlyReq, 0, size * num );
+ return earlyReq;
+ }
+ return mspace_calloc( mySpace, num, size );
+}
+
+/** Snapshotting new operator for user programs. */
+
void * operator new(size_t size) throw(std::bad_alloc) {
return malloc(size);
}
+/** Snapshotting delete operator for user programs. */
+
void operator delete(void *p) throw() {
free(p);
}
+/** Snapshotting new[] operator for user programs. */
+
void * operator new[](size_t size) throw(std::bad_alloc) {
return malloc(size);
}
+/** Snapshotting delete[] operator for user programs. */
+
void operator delete[](void *p, size_t size) {
free(p);
}