{ > How are you saaving the CFG into the .EXE?? Mind posting some code that wil > save the CFG to the EXE?(When you get all your bugs fixed!) I use these routines in my self-modifying .EXE's. They work pretty good. } Unit WritExec; { ================================================================== Unit: WritExec Author: David Doty Skipjack Software Columbia, Maryland CompuServe User I.D.: 76244,1043 This Unit is based on a previously published Program: Program: AutoInst v2.0 Author: David Dubois Zelkop Software Halifax, Nova Scotia CompuServe User I.D.: 71401,747 Date last revised: 1988.04.24 ================================================================== This source code is released to the public domain. if further changes are made, please include the above credits in the distributed code. This Unit allows a Program to change the value of a Typed Constant in its own .EXE File. When the Program is run again, the data will be initialized to the new value. No external configuration Files are necessary. Uses Examples of the usefulness of this technique would be: o A Program that allows the user to change default display colors. o A Program that keeps track of a passWord that the user can change. HOW IT WORKS You don't have to understand all the details in order to use this technique, but here they are. The data to be changed must be stored in a TurboPascal Typed Constant. In all effect, a Typed Constant is actually a pre- initialized Variable. It is always stored in the Program's Data Segment. The data can be of any Type. First, the Procedure finds the .EXE File by examining the Dos command line, stored With the copy of the Dos environment For the Program. This allows the Program to find itself no matter where is resides on disk and no matter how its name is changed by the user. The unTyped File is opened With a Record size of 1. This allows us to read or Write a String of Bytes using BlockRead and BlockWrite. As documented in the Dos Technical Reference, the size of the .EXE header, in paraGraphs (a paraGraph is 16 Bytes), is stored as a two-Byte Word at position 8 of the File. This is read into the Variable HeaderSize. The next step is to find the position of the Typed Constant in the .EXE File. This requires an understanding of the Turbo Pascal 4.0 memory map, documented on the first and second pages of the Inside Turbo Pascal chapter. (That's chapter 26, pages 335 and 336 in my manual.) First, find the address in memory where the Typed Constant is stored. This can be done in Turbo Pascal by using the Seg and Ofs Functions. Next find the segment of the PSP (Program segment prefix). This should always be the value returned by PrefixSeg. That will mark the beginning of the Program in memory. The position of the Typed Constant in the .EXE image should be the number of Bytes between these two places in memory. But ... But, two corrections must be made. First, the PSP is not stored in the .EXE File. As mentioned on page 335, the PSP is always 256 Bytes. We must subtract that out. Secondly, there is the .EXE File header. The size of this has already been read in and must be added in to our calculations. Once the position has been determined, the data stored in the Typed Constant is written in one fell swoop using a BlockWrite. This replaces the original data, so that the next time the Program is run, the new values will used. LIMITATIONS You cannot use MicroSoft's EXEPACK on the .EXE File, or any other packing method I know of. This may change the position, or even the size of the Typed Constant in the File image. NOTES Since Typed Constants are always stored in the data segment, the Function call to Seg( ObjectToWrite ) can be replaced With DSeg. I prefer using Seg since it is more descriptive. One might think that Cseg can used as an alternative to using PrefixSeg and subtracting 256. This will work only if the code resides in the main Program. If, on the other hand, the code is used in a Unit, PrefixSeg must be used as described here. You might as well use PrefixSeg and save yourself some headaches. if you have any comments or questions we would be glad to hear them. if you're on CompuServe, you can EasyPlex a letter to 76244,1043 or 71401,747. Or leave a message on the Borland Programmer's A Forum (GO BPROGA). Or, you can Write to Skipjack Software P. O. Box 61 Simpsonville Maryland 21150 or Zelkop Software P.O. Box 5177 Armdale, N.S. Canada B3L 4M7 ==================================================================} Interface Function GetExecutableName : String; { This Function returns the full drive, path, and File name of the application Program that is running. This Function is of more general interest than just For writing into the EXE File. NOTE: THIS Function WILL ONLY WORK UNDER Dos 3.X + !!! } Function WriteToExecutable(Var ObjectToWrite; ObjectSize : Word) : Integer; { This Procedure modifies the EXE File on disk to contain changes to Typed Constants. NOTE - the Object MUST be a Typed Constant. It may be found in any part of the Program (i.e., main Program or any Unit). The call is made by unTyped address, to allow any kind of Object to be written. The Function returns the Dos error code from the I/O operation that failed (if any did); if all operations were successful, the Function returns 0. } Implementation Function GetExecutableName : String; Type Environment = Array[0..32766] of Char; Const NullChar : Char = #0; SearchFailed = $FFFF; Var MyEnviron : ^Environment; Loop : Word; TempWord : Word; EnvironPos : Word; FilenamePos : Word; TempString : String; begin { Function GetExecutableName } { Get Pointer to Dos environment } MyEnviron := Ptr(MemW[PrefixSeg : $2C], 0); { Look For end of environment } EnvironPos := SearchFailed; Loop := 0; While Loop <= 32767 DO begin if MyEnviron^[ Loop ] = NullChar then if MyEnviron^[ Loop + 1 ] = NullChar then begin { found two nulls - this is end of environment } EnvironPos := Loop; Loop := 32767 end; { found two nulls } Inc(Loop); end; { While Loop } if EnvironPos = SearchFailed then GetExecutableName := '' else begin { found end of environment - now look For path/File of exec } EnvironPos := EnvironPos + 4; FilenamePos := SearchFailed; TempWord := EnvironPos; Loop := 0; While Loop <= 127 DO begin if MyEnviron^[TempWord] = NullChar then begin { found a null - this is end of path/File of exec } FilenamePos := Loop; Loop := 127 end; { found a null } Inc(Loop); Inc(TempWord); end; { While Loop } if FilenamePos = SearchFailed then GetExecutableName := '' else begin { found executable name - move into return String } TempString[0] := Chr(FilenamePos); Move(MyEnviron^[EnvironPos], TempString[1], FilenamePos); GetExecutableName := TempString; end; { found executable name } end; { found environment end } end; { Function GetExecutableName } Function WriteToExecutable(Var ObjectToWrite; ObjectSize : Word ) : Integer; Const PrefixSize = 256; { number of Bytes in the Program Segment Prefix } Var Executable : File; HeaderSize : Word; ErrorCode : Integer; begin Assign(Executable, GetExecutableName); {$I-} Reset(Executable, 1); ErrorCode := IOResult; if ErrorCode = 0 then begin { seek position of header size in EXE File } Seek(Executable, 8); ErrorCode := IOResult; end; { seek header } if ErrorCode = 0 then begin { read header size in EXE File } BlockRead(Executable, HeaderSize, SizeOf(HeaderSize)); ErrorCode := IOResult; end; { read header } if ErrorCode = 0 then begin { seek position of Object in EXE File } Seek(Executable, LongInt(16) * (HeaderSize + Seg(ObjectToWrite) - PrefixSeg) + Ofs(ObjectToWrite) - PrefixSize); ErrorCode := IOResult; end; { Seek Object position in File } if ErrorCode = 0 then begin { Write new passWord in EXE File } BlockWrite(Executable, ObjectToWrite, ObjectSize); ErrorCode := IOResult; end; { Write new passWord } Close(Executable); WriteToExecutable := ErrorCode; end; { Function WriteToExecutable } end. { Unit WritExec }