Assembler: finding shared directories problem

[maple23]

For my next project, I am making a program which searches for all of the shared directories on a computer. My idea is if the directory contains the string "share", then it must be shared.

Program Breakdown:

1. change directory to C:\ drive
2. find first directory
3. convert directory name to upper-case
4. compare upper-case directory character-by-character for the string "SHARE"
5. if the string is found, display the directory name (with a message box)
6. if the string is not found, goto step 2
7. if there are no more directories on the C:\ drive, exit

Each one of these functions works on their own (converting to upper-case, looking for "SHARE", enumerating all directories on the C:\ drive). When I put them all together, I get errors. The program executes fine until it finds a shared directory, then it fails.

Any idea what's wrong with my code?

.386
.MODEL FLAT

EXTRN	FindFirstFileA		:PROC
EXTRN	MessageBoxA		:PROC
EXTRN	FindNextFileA		:PROC
EXTRN	FindClose		:PROC
EXTRN	SetCurrentDirectoryA	:PROC
EXTRN	lstrcpyA		:PROC

MAX_PATH			equ	256

WIN32_FIND_DATA STRUC
	dwFileAttributes	dd ?
	ftCreationTime		dq ?
	ftLastAccessTime	dq ?
	ftLastWriteTime		dq ?
	nFileSizeHigh		dd ?
	nFileSizeLow		dd ?
	Reserved0		dd ?
	Reserved1		dd ?
	cFileName		db MAX_PATH dup(?)
	cAlternateFileName	db 14 dup(?)
WIN32_FIND_DATA ENDS

.DATA
	hFind		dd ?
	szMask		db "*.*", 0
	szBackDir	db "..", 0
	szDirectory	db MAX_PATH dup(?)
	win32FindData	WIN32_FIND_DATA <?>
	szDrive		db "C:\", 0

.CODE
MAIN:
	push	offset szDrive
	call	SetCurrentDirectoryA

findFirstFile:
	push	offset win32FindData
	push	offset szMask
	call	FindFirstFileA				; find first file in C:\ drive
	mov	[hFind], eax

checkType:
	cmp	eax, 0					; no files?
	je	downDirectory
	cmp	byte ptr [win32FindData.cFileName], "."
	je	findNextFile
	cmp	[win32FindData.dwFileAttributes], 10h
	je	upDirectory
	cmp	[win32FindData.dwFileAttributes], 30h
	je	upDirectory

findNextFile:
	push	offset win32FindData
	push	[hFind]
	call	FindNextFileA
	jmp	checkType

upDirectory:
	push	offset win32FindData.cFileName
	push	offset szDirectory
	call	lstrcpyA

	mov	eax, offset szDirectory

	cmp	byte ptr [eax], 90				; already uppercase? (90 = Z)
	jle	toUpperCase
	xor	byte ptr [eax], 32				; convert

toUpperCase:
	inc	eax
	cmp	byte ptr [eax], 0				; at end of string?
	je	endOfString
	cmp	byte ptr [eax], 90				; already uppercase?
	jle	toUpperCase
	xor	byte ptr [eax], 32				; convert
	jmp	toUpperCase

endOfString:
	mov	eax, 0
	mov	eax, offset szDirectory

searchShare:
	inc	eax
	cmp	byte ptr [eax], 0				; end of string?
	jne	noShare
	cmp	byte ptr [eax], "S"				; check for S
	jne	searchShare
	cmp	byte ptr [eax + 1], "H"				; check for H
	jne	searchShare
	cmp	byte ptr [eax + 2], "A"				;
	jne	searchShare
	cmp	byte ptr [eax + 3], "R"				;
	jne	searchShare
	cmp	byte ptr [eax + 4], "E"				;
	jne	searchShare

	push	0
	push	offset szDirectory
	push	offset szDirectory
	push	0
	call	MessageBoxA					; display directory

noShare:
	push	offset szDirectory
	call	SetCurrentDirectoryA
	cmp	eax, 0
	je	findNextFile

	push	hFind
	jmp	findFirstFile

downDirectory:
	push	offset szBackDir
	call	SetCurrentDirectoryA
	push	[hFind]
	call	FindClose
	pop	[hFind]
	cmp	[hFind], 0
	jne	findNextFile

theEnd:
	ret
	END	MAIN

I am using TASM 5.0 and TLINK32 to compile.

Thanks in advance!

[v0id]

I'm not a Windows programmer, so I can't help much, but have you tried using a debugger? You can use "debug" which comes with Windows, or use OllyDbg, if you prefer a graphical user interface.

[maple23]

Yes, I have Olly Debug, but I can't seem to get anywhere with it... I'm new with debuggers, and am having trouble setting a breakpoint before the program displays a messagebox.

[Xav]

Does the code compile? If not, it's a typo. If it does, you know it's some sort of runtime error - in that case, debug the code line by line, to check it executes in the way you want it to.

[maple23]

Yes, the code compiles. I will work try to debug the program tomorrow.

[Xav]

Good idea - debuggers really help to make a programmer's job easier, especially when handling errors.