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Exe File Format


A hex value of 0x14C (332 in decimal) is the code for an Intel 80386. Here is the DOS header presented as a C data structure: struct DOS_Header { // short is 2 bytes, long is 4 bytes char signature[2] = "MZ"; short lastsize; short nblocks; DWORD SizeOfUninitializedData The size of the sections that the loader commits space for in the virtual address space, but that don't take up any space in the disk file. TimeDateStamp 32 bit time at which this header was generated: is used in the process of "Binding", see below.

This includes gathering requirements, purchasing equipment and software, distributing it to where it is to be used, configuring it, maintaining it with enhancement and service updates, setting up problem-handling processes, and With every Win32-based program you start up, you get an MS-DOS-based program loaded for free! In the COFF debug format, however, the line number information is stored separately from the symbolic name/type information. In this article, I'll give a tour of the Portable Executable (PE) file format that Microsoft has designed for use by all their Win32®-based systems: Windows NT®, Win32s™, and Windows® 95.

Exe File On Mac

The one exception to this rule is for trusted services and these EXEs must have a valid checksum. In an EXE, it holds the actual size of the code or data. cmd.exe - The shell program used by Windows 2000 and later, replacing the COMMAND.COM shell. Some sections contain code or data that your program declared and uses directly, while other data sections are created for you by the linker and librarian, and contain information vital to

So, the import address can be precomputed and stored in the FirstThunk array before runtime, allowing the loader to skip resolving the imports - the imports are "bound" to a particular Instead, I'll present the concepts embedded in the PE file format and relate them to things you encounter everyday. Since many of you are coming from a background in 16-bit Windows, I'll correlate the constructs of the Win32 PE file format back to their 16-bit NE file format equivalents. Exe File Format Specification Unlike an NE file segment table, though, a PE section table doesn't store a selector value for each code or data chunk.

The fields of the IMAGE_FILE_HEADER are shown in Table 2. Exe Virus Hot Network Questions Have we attempted to experimentally confirm gravitational time dilation? EXTENSION:EXE,OVR,OVL OCCURENCES:PC PROGRAMS:MS-DOS REFERENCE:Ralf Brown's Interrupt List SEE ALSO:COM,EXE,NE EXE This information is from and is used with permission. Older programs that were linked assuming a base address of 0x10000 will take longer to load under Windows 95 because the loader needs to apply the base relocations.

The upshot of this is that companies producing OBJs or LIBs for use with multiple compilers will need to go back to distributing separate versions of their products for different compilers Exe Means Virus The first array (the one pointed at by the Characteristics field) is left alone, and never modified. If you specified a DESCRIPTION entry in your program's DEF file, the specified description string appears in the .rdata section. It's important to note that the JMP and CALL instructions that the compiler generates use offsets relative to the instruction, rather than actual offsets in the 32-bit flat segment.

Exe Virus

SizeOfCode The size of the code section, in bytes, or the sum of all such sections if there are multiple code sections. The most interesting entries in DataDirectory are as follows, Export Directory, Import Directory, Resource Directory, and the Bound Import directory. Exe File On Mac DLL's are mapped in a similar method to .exe's, with relocations occuring and their dependent DLL's being loaded. .exe File Opener For Win32, all the memory used by the module for code, data, resources, import tables, export tables, and other required module data structures is in one contiguous block of memory.

MSDN Magazine. The NE file format allows you to specify with the PRELOAD attribute which segments should be loaded at module load time. CloudAVO on my desktop won't delete! This is not possible when the location of the module in memory is not known at compile time. Exe Meaning

The "Name" value is an RVA to a zero terminated ASCII string, the name of this library name, or module. Data Management ( Find Out More About This Site ) predictive modeling Predictive modeling is a process that uses data mining and probability to forecast outcomes. Please tell us where you read or heard it (including the quote, if possible). weblink The PE file's .idata section contains the information necessary for the loader to determine the addresses of the target functions and patch them into the executable image.

Copy (Virtual address 0x10464)-(base address 0x10000) = RVA 0x00464 To convert an RVA into a usable pointer, simply add the RVA to the base address of the module. An In-depth Look Into The Win32 Portable Executable File Format However, Microsoft changed its meaning and never bothered to update WINNT.H. Also missing from the PE format is the notion of page tables.

Two 16-bit registers determine the actual address used for a memory access, a “segment” register specifying a 64K byte window into the 1M+64K byte space (in 16-byte increments) and an “offset”

Of the two formats, the LX method may allow more flexibility, but the PE style is significantly simpler and easier to work with. Instead, we will use the term "File ID Tag", or simply, File ID. Interestingly, the .idata section also has this attribute set. Pe Header Format Here is a structure that can be used to represent the EXE header and relocation entries, assuming a 16-bit LSB machine: struct EXE { unsigned short signature; /* == 0x5a4D */

As mentioned earlier, the Microsoft compilers for Win32 produce COFF-format OBJ files. For example, the notion of thread local variables, as in Copy declspec(thread) int i; drove me crazy until I saw how it was implemented with elegant simplicity in the executable file. The loader uses the memory-mapped file mechanism to map the appropriate pieces of the file into the virtual address space. Or some sort of intermediate statement that's recognized by windows which turns it into assembly for a specific processor?

MIME type: application/octet-stream, application/x-msdownload, application/exe, application/x-exe, application/dos-exe, vms/exe, application/x-winexe, application/msdos-windows, application/x-msdos-program Learn more about EXE files: Search for answers to EXE-related questions at IT Knowledge Exchange. This is a rare occurrence, however. They're just really memory ranges in a process's virtual address space. In the NE format, the location of almost everything is stored as a sector value.