小甲鱼PE详解之IMAGE_NT_HEADERS结构定义即各个属性的作用（PE详解02）

IMAGE_NT_HEADERS STRUCT

{

+0hDWORDSignature
//

+4h IMAGE_FILE_HEADER FileHeader
//

+18hIMAGE_OPTIONAL_HEADER32
OptionalHeader //

} IMAGE_NT_HEADERS ENDS

Signature 字段：

在一个有效的 PE 文件里，Signature 字段被设置为00004550h, ASCII 码字符是“PE00”。标志这 PE 文件头的开始。

“PE00” 字符串是 PE 文件头的开始，DOS 头部的 e_lfanew 字段正是指向这里。

如下图所示：



IMAGE_FILE_HEADER 结构

typedef 	struct _IMAGE_FILE_HEADER

{

+04h	WORD  		Machine;                              	// 运行平台
+06h  	WORD  		NumberOfSections;		// 文件的区块数目
+08h	DWORD 	TimeDateStamp;			// 文件创建日期和时间
+0Ch  	DWORD 	PointerToSymbolTable;		// 指向符号表(主要用于调试)
+10h 	DWORD 	NumberOfSymbols;		// 符号表中符号个数(同上)
+14h  	WORD  		SizeOfOptionalHeader;		// IMAGE_OPTIONAL_HEADER32 结构大小
+16h  	WORD  		Characteristics;			// 文件属性
} IMAGE_FILE_HEADER,  *PIMAGE_FILE_HEADER;

该结构如下图所示：

下边，小甲鱼童鞋为大家详细解释各个成员的含义和用法：



（1）Machine：可执行文件的目标CPU类型。

Value	Meaning
IMAGE_FILE_MACHINE_I3860x014c	x86
IMAGE_FILE_MACHINE_IA640x0200	Intel Itanium
IMAGE_FILE_MACHINE_AMD640x8664	x64

（2）NumberOfSection: 区块的数目。（注：区块表是紧跟在 IMAGE_NT_HEADERS 后边的）

（3）TimeDataStamp: 表明文件是何时被创建的。

这个值是自1970年1月1日以来用格林威治时间（GMT）计算的秒数，这个值是比文件系统（FILESYSTEM）的日期时间更加精确的指示器。如何将这个值翻译请看：http://bbs.fishc.com/space.php?uid=9&do=blog&id=555

提示：VC的话可以用_ctime 函数或者 gmtime 函数。

（4）PointerToSymbolTable: COFF 符号表的文件偏移位置，现在基本没用了。

（5）NumberOfSymbols: 如果有COFF 符号表，它代表其中的符号数目，COFF符号是一个大小固定的结构，如果想找到COFF 符号表的结束位置，则需要这个变量。

（6）SizeOfOptionalHeader: 紧跟着IMAGE_FILE_HEADER 后边的数据结构（IMAGE_OPTIONAL_HEADER）的大小。(对于32位PE文件，这个值通常是00E0h；对于64位PE32+文件，这个值是00F0h )。

（7）Characteristics: 文件属性，有选择的通过几个值可以运算得到。( 这些标志的有效值是定义于 winnt.h 内的 IMAGE_FILE_** 的值，具体含义见下表。普通的EXE文件这个字段的值一般是 0100h，DLL文件这个字段的值一般是 210Eh。)小甲鱼温馨提示：多种属性可以通过 “或运算” 使得同时拥有！

The characteristics of the image. This member can be one or more of the following values.

Value	Meaning
IMAGE_FILE_RELOCS_STRIPPED 0x0001	Relocation information was stripped from the file. The file must be loaded at its preferred base address. If the base address is not available, the loader reports an error.
IMAGE_FILE_EXECUTABLE_IMAGE0x0002	The file is executable (there are no unresolved external references).
IMAGE_FILE_LINE_NUMS_STRIPPED0x0004	COFF line numbers were stripped from the file.
IMAGE_FILE_LOCAL_SYMS_STRIPPED0x0008	COFF symbol table entries were stripped from file.
IMAGE_FILE_AGGRESIVE_WS_TRIM0x0010	Aggressively trim the working set. This value is obsolete as of Windows 2000.
IMAGE_FILE_LARGE_ADDRESS_AWARE0x0020	The application can handle addresses larger than 2 GB.
IMAGE_FILE_BYTES_REVERSED_LO0x0080	The bytes of the word are reversed. This flag is obsolete.
IMAGE_FILE_32BIT_MACHINE0x0100	The computer supports 32-bit words.
IMAGE_FILE_DEBUG_STRIPPED0x0200	Debugging information was removed and stored separately in another file.
IMAGE_FILE_REMOVABLE_RUN_FROM_SWAP0x0400	If the image is on removable media, copy it to and run it from the swap file.
IMAGE_FILE_NET_RUN_FROM_SWAP0x0800	If the image is on the network, copy it to and run it from the swap file.
IMAGE_FILE_SYSTEM0x1000	The image is a system file.
IMAGE_FILE_DLL0x2000	The image is a DLL file. While it is an executable file, it cannot be run directly.
IMAGE_FILE_UP_SYSTEM_ONLY0x4000	The file should be run only on a uniprocessor computer.
IMAGE_FILE_BYTES_REVERSED_HI0x8000	The bytes of the word are reversed. This flag is obsolete.