reactos操作系统实现(50)

当运行到内核函数Phase1Initialization里，就是进行内核第一阶段初始化了，这时在这个函数又调用函数Phase1InitializationDiscard进行复杂的处理，在这里有一个重要的步骤，就是打开内核应用程序smss.exe来运行。具体代码如下：

#001 /* Update progress bar */

#002 InbvUpdateProgressBar(90);

#003

#004 /* Launch initial process */

#005 ProcessInfo = &InitBuffer->ProcessInfo;

#006 ExpLoadInitialProcess(InitBuffer,&ProcessParameters,&Environment);

#007

#008 DPRINT1("ExpLoadInitialProcess/n");

#009

#010 /* Update progress bar */

#011 InbvUpdateProgressBar(100);

上面代码就是通过调用函数ExpLoadInitialProcess来初始化一个内核应用程序运行，它的代码如下：

#001 VOID

#002 NTAPI

#003 ExpLoadInitialProcess(IN PINIT_BUFFER InitBuffer,

#004 OUT PRTL_USER_PROCESS_PARAMETERS *ProcessParameters,

#005 OUT PCHAR *ProcessEnvironment)

#006 {

#007 NTSTATUS Status;

#008 ULONG Size;

#009 PWSTR p;

#010 UNICODE_STRING NullString = RTL_CONSTANT_STRING(L"");

#011 UNICODE_STRING SmssName,Environment,SystemDriveString,DebugString;

#012 PVOID EnvironmentPtr = NULL;

#013 PRTL_USER_PROCESS_INFORMATION ProcessInformation;

#014 PRTL_USER_PROCESS_PARAMETERS ProcessParams = NULL;

#015

#016 NullString.Length = sizeof(WCHAR);

#017

获取处理器信息。

#018 /* Use the initial buffer,after the strings */

#019 ProcessInformation = &InitBuffer->ProcessInfo;

#020

给处理器参数分配内存。

#021 /* Allocate memory for the process parameters */

#022 Size = sizeof(*ProcessParams) + ((MAX_PATH * 6) * sizeof(WCHAR));

#023 Status = ZwAllocateVirtualMemory(NtCurrentProcess(),

#024 (PVOID*)&ProcessParams,

#025 0,

#026 &Size,

#027 MEM_COMMIT,

#028 PAGE_READWRITE);

#029 if (!NT_SUCCESS(Status))

#030 {

显示出错信息。

#031 /* Failed,display error */

#032 p = InitBuffer->DebugBuffer;

#033 _snwprintf(p,

#034 256 * sizeof(WCHAR),

#035 L"INIT: Unable to allocate Process Parameters. 0x%lx",

#036 Status);

#037 RtlInitUnicodeString(&DebugString,p);

#038 ZwDisplayString(&DebugString);

#039

#040 /* Bugcheck the system */

#041 KeBugCheckEx(SESSION1_INITIALIZATION_FAILED,Status,0);

#042 }

#043

设置处理器参数。

#044 /* Setup the basic header,and give the process the low 1MB to itself */

#045 ProcessParams->Length = Size;

#046 ProcessParams->MaximumLength = Size;

#047 ProcessParams->Flags = RTL_USER_PROCESS_PARAMETERS_NORMALIZED |

#048 RTL_USER_PROCESS_PARAMETERS_RESERVE_1MB;

#049

分配一页作环境内存使用。

#050 /* Allocate a page for the environment */

#051 Size = PAGE_SIZE;

#052 Status = ZwAllocateVirtualMemory(NtCurrentProcess(),

#053 &EnvironmentPtr,

#054 0,

#055 &Size,

#056 MEM_COMMIT,

#057 PAGE_READWRITE);

#058 if (!NT_SUCCESS(Status))

#059 {

#060 /* Failed,display error */

#061 p = InitBuffer->DebugBuffer;

#062 _snwprintf(p,

#063 256 * sizeof(WCHAR),

#064 L"INIT: Unable to allocate Process Environment. 0x%lx",

#065 Status);

#066 RtlInitUnicodeString(&DebugString,p);

#067 ZwDisplayString(&DebugString);

#068

#069 /* Bugcheck the system */

#070 KeBugCheckEx(SESSION2_INITIALIZATION_FAILED,0);

#071 }

#072

#073 /* Write the pointer */

#074 ProcessParams->Environment = EnvironmentPtr;

#075

#076 /* Make a buffer for the DOS path */

#077 p = (PWSTR)(ProcessParams + 1);

#078 ProcessParams->CurrentDirectory.DosPath.Buffer = p;

#079 ProcessParams->CurrentDirectory.DosPath.MaximumLength = MAX_PATH *

#080 sizeof(WCHAR);

#081

#082 /* Copy the DOS path */

#083 RtlCopyUnicodeString(&ProcessParams->CurrentDirectory.DosPath,

#084 &NtSystemRoot);

#085

#086 /* Make a buffer for the DLL Path */

#087 p = (PWSTR)((PCHAR)ProcessParams->CurrentDirectory.DosPath.Buffer +

#088 ProcessParams->CurrentDirectory.DosPath.MaximumLength);

#089 ProcessParams->DllPath.Buffer = p;

#090 ProcessParams->DllPath.MaximumLength = MAX_PATH * sizeof(WCHAR);

#091

拷贝SYSTEM32的目录。

#092 /* Copy the DLL path and append the system32 directory */

#093 RtlCopyUnicodeString(&ProcessParams->DllPath,

#094 &ProcessParams->CurrentDirectory.DosPath);

#095 RtlAppendUnicodeToString(&ProcessParams->DllPath,L"//System32");

#096

#097 /* Make a buffer for the image name */

#098 p = (PWSTR)((PCHAR)ProcessParams->DllPath.Buffer +

#099 ProcessParams->DllPath.MaximumLength);

#100 ProcessParams->ImagePathName.Buffer = p;

#101 ProcessParams->ImagePathName.MaximumLength = MAX_PATH * sizeof(WCHAR);

#102

#103 /* Make sure the buffer is a valid string which within the given length */

#104 if ((NtInitialUserProcessBufferType != REG_SZ) ||

#105 ((NtInitialUserProcessBufferLength != -1U) &&

#106 ((NtInitialUserProcessBufferLength < sizeof(WCHAR)) ||

#107 (NtInitialUserProcessBufferLength >

#108 sizeof(NtInitialUserProcessBuffer) - sizeof(WCHAR)))))

#109 {

#110 /* Invalid initial process string,bugcheck */

#111 KeBugCheckEx(SESSION2_INITIALIZATION_FAILED,

#112 STATUS_INVALID_PARAMETER,

#113 NtInitialUserProcessBufferType,

#114 NtInitialUserProcessBufferLength,

#115 sizeof(NtInitialUserProcessBuffer));

#116 }

#117

#118 /* Cut out anything after a space */

#119 p = NtInitialUserProcessBuffer;

#120 while ((*p) && (*p != L' ')) p++;

#121

#122 /* Set the image path length */

#123 ProcessParams->ImagePathName.Length =

#124 (USHORT)((PCHAR)p - (PCHAR)NtInitialUserProcessBuffer);

#125

#126 /* Copy the actual buffer */

#127 RtlCopyMemory(ProcessParams->ImagePathName.Buffer,

#128 NtInitialUserProcessBuffer,

#129 ProcessParams->ImagePathName.Length);

#130

#131 /* Null-terminate it */

#132 ProcessParams->ImagePathName.Buffer[ProcessParams->ImagePathName.Length /

#133 sizeof(WCHAR)] = UNICODE_NULL;

#134

#135 /* Make a buffer for the command line */

#136 p = (PWSTR)((PCHAR)ProcessParams->ImagePathName.Buffer +

#137 ProcessParams->ImagePathName.MaximumLength);

#138 ProcessParams->CommandLine.Buffer = p;

#139 ProcessParams->CommandLine.MaximumLength = MAX_PATH * sizeof(WCHAR);

#140

#141 /* Add the image name to the command line */

#142 RtlAppendUnicodeToString(&ProcessParams->CommandLine,

#143 NtInitialUserProcessBuffer);

#144

#145 /* Create the environment string */

#146 RtlInitEmptyUnicodeString(&Environment,

#147 ProcessParams->Environment,

#148 (USHORT)Size);

#149

#150 /* Append the DLL path to it */

#151 RtlAppendUnicodeToString(&Environment,L"Path=" );

#152 RtlAppendUnicodeStringToString(&Environment,&ProcessParams->DllPath);

#153 RtlAppendUnicodeStringToString(&Environment,&NullString);

#154

#155 /* Create the system drive string */

#156 SystemDriveString = NtSystemRoot;

#157 SystemDriveString.Length = 2 * sizeof(WCHAR);

#158

#159 /* Append it to the environment */

#160 RtlAppendUnicodeToString(&Environment,L"SystemDrive=");

#161 RtlAppendUnicodeStringToString(&Environment,&SystemDriveString);

#162 RtlAppendUnicodeStringToString(&Environment,&NullString);

#163

#164 /* Append the system root to the environment */

#165 RtlAppendUnicodeToString(&Environment,L"SystemRoot=");

#166 RtlAppendUnicodeStringToString(&Environment,&NtSystemRoot);

#167 RtlAppendUnicodeStringToString(&Environment,&NullString);

#168

#169 /* Prepare the prefetcher */

#170 //CcPfBeginBootPhase(150);

#171

这里加载smss.exe程序，并创建一个进程运行。当是安装的时候，已经在制作光盘时，把usetup.exe文件改名为smss.exe文件，所以这里运行的就是usetup.exe程序。

#172 /* Create SMSS process */

#173 SmssName = ProcessParams->ImagePathName;

#174 Status = RtlCreateUserProcess(&SmssName,

#175 OBJ_CASE_INSENSITIVE,

#176 RtlDeNormalizeProcessParams(ProcessParams),

#177 NULL,

#178 NULL,

#179 NULL,

#180 FALSE,

#181 NULL,

#182 NULL,

#183 ProcessInformation);

#184 if (!NT_SUCCESS(Status))

#185 {

#186 /* Failed,display error */

#187 p = InitBuffer->DebugBuffer;

#188 _snwprintf(p,

#189 256 * sizeof(WCHAR),

#190 L"INIT: Unable to create Session Manager. 0x%lx",

#191 Status);

#192 RtlInitUnicodeString(&DebugString,p);

#193 ZwDisplayString(&DebugString);

#194

#195 /* Bugcheck the system */

#196 KeBugCheckEx(SESSION3_INITIALIZATION_FAILED,0);

#197 }

#198

#199 /* Resume the thread */

#200 Status = ZwResumeThread(ProcessInformation->ThreadHandle,NULL);

#201 if (!NT_SUCCESS(Status))

#202 {

#203 /* Failed,display error */

#204 p = InitBuffer->DebugBuffer;

#205 _snwprintf(p,

#206 256 * sizeof(WCHAR),

#207 L"INIT: Unable to resume Session Manager. 0x%lx",

#208 Status);

#209 RtlInitUnicodeString(&DebugString,p);

#210 ZwDisplayString(&DebugString);

#211

#212 /* Bugcheck the system */

#213 KeBugCheckEx(SESSION4_INITIALIZATION_FAILED,0);

#214 }

#215

#216 /* Return success */

#217 *ProcessParameters = ProcessParams;

#218 *ProcessEnvironment = EnvironmentPtr;

#219 }

通过上面的过程，就可以把usetup.exe安装程序运行起来了。结果就出现下面的界面：

（编辑：李大同）

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