startup.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

   PEPFUNC EntryPoint;
   PIMAGE_DOS_HEADER PEDosHeader;
   PVOID ImageBase;
   PPEB Peb;
   PLDR_DATA_TABLE_ENTRY NtModule;  // ntdll
   NLSTABLEINFO NlsTable;
   WCHAR FullNtDllPath[MAX_PATH];
   SYSTEM_BASIC_INFORMATION SystemInformation;
   NTSTATUS Status;

   DPRINT("LdrpInit()\n");
   if (NtCurrentPeb()->Ldr == NULL || NtCurrentPeb()->Ldr->Initialized == FALSE)
     {
       Peb = NtCurrentPeb();
       DPRINT("Peb %p\n", Peb);
       ImageBase = Peb->ImageBaseAddress;
       DPRINT("ImageBase %p\n", ImageBase);
       if (ImageBase <= (PVOID)0x1000)
         {
           DPRINT("ImageBase is null\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INVALID_IMAGE_FORMAT);
         }

       /*  If MZ header exists  */
       PEDosHeader = (PIMAGE_DOS_HEADER) ImageBase;
       DPRINT("PEDosHeader %p\n", PEDosHeader);

       if (PEDosHeader->e_magic != IMAGE_DOS_SIGNATURE ||
           PEDosHeader->e_lfanew == 0L ||
           *(PULONG)((PUCHAR)ImageBase + PEDosHeader->e_lfanew) != IMAGE_NT_SIGNATURE)
         {
           DPRINT1("Image has bad header\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INVALID_IMAGE_FORMAT);
         }

       /* normalize process parameters */
       RtlNormalizeProcessParams (Peb->ProcessParameters);

       /* Initialize NLS data */
       RtlInitNlsTables (Peb->AnsiCodePageData,
                         Peb->OemCodePageData,
                         Peb->UnicodeCaseTableData,
                         &NlsTable);
       RtlResetRtlTranslations (&NlsTable);

       NTHeaders = (PIMAGE_NT_HEADERS)((ULONG_PTR)ImageBase + PEDosHeader->e_lfanew);

       /* Get number of processors */
       DPRINT("Here\n");
       Status = ZwQuerySystemInformation(SystemBasicInformation,
	                                 &SystemInformation,
					 sizeof(SYSTEM_BASIC_INFORMATION),
					 NULL);
        DPRINT("Here2\n");
       if (!NT_SUCCESS(Status))
         {
	   ZwTerminateProcess(NtCurrentProcess(), Status);
	 }

       Peb->NumberOfProcessors = SystemInformation.NumberOfProcessors;

       /* Initialize Critical Section Data */
       RtlpInitDeferedCriticalSection();

       /* create process heap */
       RtlInitializeHeapManager();
       Peb->ProcessHeap = RtlCreateHeap(HEAP_GROWABLE,
                                        NULL,
                                        NTHeaders->OptionalHeader.SizeOfHeapReserve,
                                        NTHeaders->OptionalHeader.SizeOfHeapCommit,
                                        NULL,
                                        NULL);
       if (Peb->ProcessHeap == 0)
         {
           DPRINT1("Failed to create process heap\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INSUFFICIENT_RESOURCES);
         }

       /* initialized vectored exception handling */
       RtlpInitializeVectoredExceptionHandling();

       /* initalize peb lock support */
       RtlInitializeCriticalSection (&PebLock);
       Peb->FastPebLock = &PebLock;
       Peb->FastPebLockRoutine = (PPEBLOCKROUTINE)RtlEnterCriticalSection;
       Peb->FastPebUnlockRoutine = (PPEBLOCKROUTINE)RtlLeaveCriticalSection;

       /* initialize tls bitmap */
       RtlInitializeBitMap (&TlsBitMap,
                            Peb->TlsBitmapBits,
                            TLS_MINIMUM_AVAILABLE);
       Peb->TlsBitmap = &TlsBitMap;
       Peb->TlsExpansionCounter = TLS_MINIMUM_AVAILABLE;

       /* Initialize table of callbacks for the kernel. */
       Peb->KernelCallbackTable =
         RtlAllocateHeap(RtlGetProcessHeap(),
                         0,
                         sizeof(PVOID) * (USER32_CALLBACK_MAXIMUM + 1));
       if (Peb->KernelCallbackTable == NULL)
         {
           DPRINT1("Failed to create callback table\n");
           ZwTerminateProcess(NtCurrentProcess(),STATUS_INSUFFICIENT_RESOURCES);
         }

       /* initalize loader lock */
       RtlInitializeCriticalSection (&LoaderLock);
       Peb->LoaderLock = &LoaderLock;

       /* create loader information */
       Peb->Ldr = (PPEB_LDR_DATA)RtlAllocateHeap (Peb->ProcessHeap,
                                                  0,
                                                  sizeof(PEB_LDR_DATA));
       if (Peb->Ldr == NULL)
         {
           DPRINT1("Failed to create loader data\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INSUFFICIENT_RESOURCES);
         }
       Peb->Ldr->Length = sizeof(PEB_LDR_DATA);
       Peb->Ldr->Initialized = FALSE;
       Peb->Ldr->SsHandle = NULL;
       InitializeListHead(&Peb->Ldr->InLoadOrderModuleList);
       InitializeListHead(&Peb->Ldr->InMemoryOrderModuleList);
       InitializeListHead(&Peb->Ldr->InInitializationOrderModuleList);

       /* Load compatibility settings */
       LoadCompatibilitySettings(Peb);

       /* Load execution options */
       LoadImageFileExecutionOptions(Peb);

       /* Initialize the static teb string */
       NtCurrentTeb()->StaticUnicodeString.Length = 0;
       NtCurrentTeb()->StaticUnicodeString.MaximumLength = sizeof(NtCurrentTeb()->StaticUnicodeBuffer);
       NtCurrentTeb()->StaticUnicodeString.Buffer = NtCurrentTeb()->StaticUnicodeBuffer;

       /* build full ntdll path */
       wcscpy (FullNtDllPath, SharedUserData->NtSystemRoot);
       wcscat (FullNtDllPath, L"\\system32\\ntdll.dll");

       /* add entry for ntdll */
       NtModule = (PLDR_DATA_TABLE_ENTRY)RtlAllocateHeap (Peb->ProcessHeap,
                                                0,
                                                sizeof(LDR_DATA_TABLE_ENTRY));
       if (NtModule == NULL)
         {
           DPRINT1("Failed to create loader module entry (NTDLL)\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INSUFFICIENT_RESOURCES);
	 }
       memset(NtModule, 0, sizeof(LDR_DATA_TABLE_ENTRY));

       NtModule->DllBase = (PVOID)&_image_base__;
       NtModule->EntryPoint = 0; /* no entry point */
       RtlCreateUnicodeString (&NtModule->FullDllName,
                               FullNtDllPath);
       RtlCreateUnicodeString (&NtModule->BaseDllName,
                               L"ntdll.dll");
       NtModule->Flags = LDRP_IMAGE_DLL|LDRP_ENTRY_PROCESSED;

       NtModule->LoadCount = -1; /* don't unload */
       NtModule->TlsIndex = -1;
       NtModule->SectionPointer = NULL;
       NtModule->CheckSum = 0;

       NTHeaders = RtlImageNtHeader (NtModule->DllBase);
       NtModule->SizeOfImage = LdrpGetResidentSize(NTHeaders);
       NtModule->TimeDateStamp = NTHeaders->FileHeader.TimeDateStamp;

       InsertTailList(&Peb->Ldr->InLoadOrderModuleList,
                      &NtModule->InLoadOrderLinks);
       InsertTailList(&Peb->Ldr->InInitializationOrderModuleList,
                      &NtModule->InInitializationOrderModuleList);

#if defined(DBG) || defined(KDBG)

       LdrpLoadUserModuleSymbols(NtModule);

#endif /* DBG || KDBG */

       /* add entry for executable (becomes first list entry) */
       ExeModule = (PLDR_DATA_TABLE_ENTRY)RtlAllocateHeap (Peb->ProcessHeap,
                                                 0,
                                                 sizeof(LDR_DATA_TABLE_ENTRY));
       if (ExeModule == NULL)
         {
           DPRINT1("Failed to create loader module infomation\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INSUFFICIENT_RESOURCES);
         }
       ExeModule->DllBase = Peb->ImageBaseAddress;

       if ((Peb->ProcessParameters == NULL) ||
           (Peb->ProcessParameters->ImagePathName.Length == 0))
         {
           DPRINT1("Failed to access the process parameter block\n");
           ZwTerminateProcess(NtCurrentProcess(),STATUS_UNSUCCESSFUL);
         }

       RtlCreateUnicodeString(&ExeModule->FullDllName,
                              Peb->ProcessParameters->ImagePathName.Buffer);
       RtlCreateUnicodeString(&ExeModule->BaseDllName,
                              wcsrchr(ExeModule->FullDllName.Buffer, L'\\') + 1);

       DPRINT("BaseDllName '%wZ'  FullDllName '%wZ'\n",
              &ExeModule->BaseDllName,
              &ExeModule->FullDllName);

       ExeModule->Flags = LDRP_ENTRY_PROCESSED;
       ExeModule->LoadCount = -1; /* don't unload */
       ExeModule->TlsIndex = -1;
       ExeModule->SectionPointer = NULL;
       ExeModule->CheckSum = 0;

       NTHeaders = RtlImageNtHeader (ExeModule->DllBase);
       ExeModule->SizeOfImage = LdrpGetResidentSize(NTHeaders);
       ExeModule->TimeDateStamp = NTHeaders->FileHeader.TimeDateStamp;

       InsertHeadList(&Peb->Ldr->InLoadOrderModuleList,
                      &ExeModule->InLoadOrderLinks);

       LdrpInitLoader();

#if defined(DBG) || defined(KDBG)

       LdrpLoadUserModuleSymbols(ExeModule);

#endif /* DBG || KDBG */

       EntryPoint = LdrPEStartup((PVOID)ImageBase, NULL, NULL, NULL);
       ExeModule->EntryPoint = EntryPoint;

       /* all required dlls are loaded now */
       Peb->Ldr->Initialized = TRUE;

       /* Check before returning that we can run the image safely. */
       if (EntryPoint == NULL)
         {
           DPRINT1("Failed to initialize image\n");
           ZwTerminateProcess(NtCurrentProcess(), STATUS_INVALID_IMAGE_FORMAT);
         }
     }
   /* attach the thread */
   RtlEnterCriticalSection(NtCurrentPeb()->LoaderLock);
   LdrpAttachThread();
   RtlLeaveCriticalSection(NtCurrentPeb()->LoaderLock);
}

/* EOF */