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rpcrt4: Change the allocation of delegated stub methods so that we never need to free them.

This commit is contained in:
Alexandre Julliard 2009-06-01 16:40:44 +02:00
parent 3838f4b21a
commit 0357ad0894
1 changed files with 49 additions and 35 deletions
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84
dlls/rpcrt4/cstub.c
View File

@ -113,7 +113,6 @@ typedef struct
{
DWORD ref;
DWORD size;
void **methods;
IUnknownVtbl vtbl;
/* remaining entries in vtbl */
} ref_counted_vtbl;
@ -161,45 +160,67 @@ typedef struct {
} vtbl_method_t;
#include "poppack.h"
static void fill_table(IUnknownVtbl *vtbl, void **methods, DWORD num)
#define BLOCK_SIZE 1024
#define MAX_BLOCKS 64 /* 64k methods should be enough for anybody */
static const vtbl_method_t *method_blocks[MAX_BLOCKS];
static const vtbl_method_t *allocate_block( unsigned int num )
{
vtbl_method_t *method;
void **entry;
DWORD i;
unsigned int i;
vtbl_method_t *prev, *block;
block = VirtualAlloc( NULL, BLOCK_SIZE * sizeof(*block),
MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE );
if (!block) return NULL;
for (i = 0; i < BLOCK_SIZE; i++)
{
block[i].mov1 = 0x0424448b;
block[i].mov2 = 0x408b;
block[i].sixteen = 0x10;
block[i].mov3 = 0x04244489;
block[i].mov4 = 0x008b;
block[i].mov5 = 0x808b;
block[i].offset = (BLOCK_SIZE * num + i + 3) << 2;
block[i].jmp = 0xe0ff;
block[i].pad[0] = 0x8d;
block[i].pad[1] = 0x76;
block[i].pad[2] = 0x00;
}
VirtualProtect( block, BLOCK_SIZE * sizeof(*block), PAGE_EXECUTE_READ, NULL );
prev = InterlockedCompareExchangePointer( (void **)&method_blocks[num], block, NULL );
if (prev) /* someone beat us to it */
{
VirtualFree( block, 0, MEM_RELEASE );
block = prev;
}
return block;
}
static BOOL fill_delegated_stub_table(IUnknownVtbl *vtbl, DWORD num)
{
const void **entry = (const void **)(vtbl + 1);
DWORD i, j;
vtbl->QueryInterface = delegating_QueryInterface;
vtbl->AddRef = delegating_AddRef;
vtbl->Release = delegating_Release;
method = (vtbl_method_t*)methods;
entry = (void**)(vtbl + 1);
for(i = 3; i < num; i++)
for (i = 0; i < (num - 3 + BLOCK_SIZE - 1) / BLOCK_SIZE; i++)
{
*entry = method;
method->mov1 = 0x0424448b;
method->mov2 = 0x408b;
method->sixteen = 0x10;
method->mov3 = 0x04244489;
method->mov4 = 0x008b;
method->mov5 = 0x808b;
method->offset = i << 2;
method->jmp = 0xe0ff;
method->pad[0] = 0x8d;
method->pad[1] = 0x76;
method->pad[2] = 0x00;
method++;
entry++;
const vtbl_method_t *block = method_blocks[i];
if (!block && !(block = allocate_block( i ))) return FALSE;
for (j = 0; j < BLOCK_SIZE && j < num - 3 - i * BLOCK_SIZE; j++) *entry++ = &block[j];
}
return TRUE;
}
#else /* __i386__ */
typedef struct {int dummy;} vtbl_method_t;
static void fill_table(IUnknownVtbl *vtbl, void **methods, DWORD num)
static BOOL fill_delegated_stub_table(IUnknownVtbl *vtbl, DWORD num)
{
ERR("delegated stubs are not supported on this architecture\n");
return FALSE;
}
#endif /* __i386__ */
@ -216,21 +237,15 @@ void create_delegating_vtbl(DWORD num_methods)
EnterCriticalSection(&delegating_vtbl_section);
if(!current_vtbl.table || num_methods > current_vtbl.table->size)
{
DWORD size;
DWORD old_protect;
if(current_vtbl.table && current_vtbl.table->ref == 0)
{
TRACE("freeing old table\n");
VirtualFree(current_vtbl.table->methods, 0, MEM_RELEASE);
HeapFree(GetProcessHeap(), 0, current_vtbl.table);
}
size = (num_methods - 3) * sizeof(vtbl_method_t);
current_vtbl.table = HeapAlloc(GetProcessHeap(), 0, FIELD_OFFSET(ref_counted_vtbl, vtbl) + num_methods * sizeof(void*));
current_vtbl.table->ref = 0;
current_vtbl.table->size = num_methods;
current_vtbl.table->methods = VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
fill_table(&current_vtbl.table->vtbl, current_vtbl.table->methods, num_methods);
VirtualProtect(current_vtbl.table->methods, size, PAGE_EXECUTE_READ, &old_protect);
fill_delegated_stub_table(&current_vtbl.table->vtbl, num_methods);
}
LeaveCriticalSection(&delegating_vtbl_section);
}
@ -256,7 +271,6 @@ static void release_delegating_vtbl(IUnknownVtbl *vtbl)
if(table->ref == 0 && table != current_vtbl.table)
{
TRACE("... and we're not current so free'ing\n");
VirtualFree(current_vtbl.table->methods, 0, MEM_RELEASE);
HeapFree(GetProcessHeap(), 0, table);
}
LeaveCriticalSection(&delegating_vtbl_section);