
	P A R S E L I B
	---------------

PLB stands for parselib.
It processes OMF object and library files and produces a pattern file.
Command line:

	parselib [-sw or @file] input-file pattern-file

The command line switches may be placed in an indirect file - one switch per line.
The input file is an object file or a library file. If the extension is omitted,
"LIB" extension is assumed.
The output file is a pattern file. Its default extension is "PAT".
A pattern file is a simple text file. Each function is represented by one
line (warning: the lines may be very-very long, tens of kilobytes, so don't
edit pattern files with a text editor). Format of this file is described
in the PAT.TXT file.

Usually plb is launched without switches:

	plb cl1 borland

will take "cl2.lib" as input and produce "borland.pat" file.

You may use the -a switch to append to the output file:

	plb -a cl2 borland

will append patterns of functions from "cl2.lib" to "borland.pat"
The output file must exist if the -a switch is used.

Description of switches
-----------------------

	-a	Append to the output file. The output file must exist and
		its last line must be '---'

	-c...	If the input file contains the "ctype" array, you may use
		this switch to allow parselib to detect the "ctype" array and
		produce a special record in the pattern file for it.
		"Ctype" array requires special handling because it resides
		in data segment and normally would be skipped by parselib.
		You should specify ctype array name:

			-cctype_name

		Use this switch only if you are processing a non-standard C
		library.

	-d	Turn on debugging. Displays lots of debugging information.

	-e	Skip unnamed functions. Experimental switch. I don't recommend
		to use it - it is better to recognize even unnamed functions
		rather than silently skip them.

	-i	The input file is an IBM OMF file.
		By default parselib assumes the input file to be a MS OMF file.

	-l...	This switch is required only for startup object modules.
		It should not be specified for regular libraries.
		This switch contains information how to proceed if the
		startup module is found in the executable file.
		It allows you to specify names of signature files to be
		applied automatically. Signature file names are separated by
		':'. Optional signature files are specified as l=signame
		Also, you may specify the OS type and the application type.
		Format of this switch is signature names and directives
		separated by colons ':', for example:

		      o=type:a=type:l=lib1/lib2/lib3:m=hints:s=off/signame

		o=type
			specifies OS type if the startup module is found.
			Valid values (sigmake -ho displays them):
			  1 MS DOS
			  2 MS Windows
			  4 OS/2
			  8 Netware

		a=type
			specifies application type if the startup module is
			found in the executable file.
			Valid values are combination of the following
			bits (sigmake -ha displays them):
			  0001 console
			  0002 graphics
			  0004 program (EXE)
			  0008 library (DLL)
			  0010 driver  (VxD)
			  0020 Single-threaded
			  0040 Multi-threaded
			  0080 16bit
			  0100 32bit
			When in question, don't specify a bit.

		l=lib1/lib2/lib3...
			Optional signatures. This directive may be omitted.
			An optional signature file is not applied
			automatically, but it will be marked with an asterisk
			in the list of signature files.

		m=hints
			A simple program to find main() function. Format of
			hints is decribed below. This directive may be omitted.

		s=off/signame
			Reference to secondary startup signature. Presence of
			this directive means that IDA can't make decision
			based on the recognition of one startup module.
			IDA needs to make additional checks to select
			proper signature file: these additional checks are
			in the secondary signature file. The secondary
			signature file will be applied to an address referenced
			by an instruction at start+off (off is hexadecimal).
			This directive must be the last item in the -l switch.
			This directive may be omitted.

		S=off/signame
			Almost the same thing as lowercase 's'. The difference
			between these switches is that the uppercase 'S' uses the
			start+off address as it is while
			the lowecase 's' tries to get the address referenced by the
			instruction. The start address mentioned in this switches
			is either the address where the signature was applied to
			(usually the entry point of the program) or the address
			after applying the main() hints (if they were specified
			before)

		M=off/signame
			Similar to 'S', with the difference that, if the second
			startup signature fails to find a match, the last main()
			function detected with the hints is applied.

		i=idcfile
			An IDC file to invoke. The IDC file will be searched
			in the IDC subdirectory of IDA.

		c=comp_id
			Specify compiler. comp_id is a character:
			  v: Visual C++
			  b: Borland C++
			  w: Watcom C++
			  g: GNU C++
			  a: Visual Age C++
			  d: Delphi
			This compiler will be used if the compiler is not known.

	-L	Preserve bytes before first label at the beginning of the pattern.
		By default, the bytes before the first label are removed.
		These bytes are usually filler (CC or NOPs), but they may also
		refer to read-only data used by the function.
		Note: for ARM, thumb function addresses are incremented by one,
		      so this option must not be used.

	-m...	The name of the library module. If this switch is specified,
		parselib will process only the specified module, not the whole
		library. This switch is mainly used for startup modules.

	-n...	The name of the startup function. If this switch is specified,
		parselib will start pattern at the specified function,
		not at the module start. Signatures are applied to
		the entry point of an executable file and therefore
		the patterns should start at entry point too.

	-o...	The offset of the startup entry point (hex). The pattern will start at it.
		This is an alternative way to specify the start of a startup
		pattern. Sometimes the entry point has no name and in this
		case we are forced to use offsets instead of names.

	-p##	Pattern length (default: 32)

	-v	Verbose output

	-w...	This switch has the same meaning as -c switch.
		The only difference is that ctype array has 2-byte elements.

	-z	Loosen input file format checks. Some library modules have
		erroneous structure. This switch allows parselib to handle
		them.


Format of hints used to find main() function
--------------------------------------------

Hints are arranged as a simple program encoded in a text string.
The string is processed from the left to the right. For the ease of explanation, let's
imagine a virtual machine with the following registers:
	PTR	- contains a pointer to hints string.
		  initialized with the start of the hints string.
	ADR	- contains the current linear address.
		  initialized with the executable program entry point address.
	MAIN	- contains a possible main() address. initialized with
		  a bad address (i.e. the main() address in not known)
	MAINNAME- contains a possible main() function name.
	SAFE	- contains a 'safe' address. not initialized.
	FLAG	- contains 1/0. Initialized with 0.

The virtual machine takes a symbol at PTR, interprets it accordingly and
moves PTR to the next symbol. The execution is stopped when one of the
following conditions reached:
	- the end of the string is reached. The address of the main()
          function is in MAIN (unless it still contains the bad address)
	- PTR points to a '/' symbol. It means that the main() function is found at ADR.
	- illegal symbol at PTR is encountered.


Elements of hints string (spaces are inserted for readibility only. they
should not be present in the program string):

  + <off>	ADR <- ADR + off.
  		off is a hexadecimal number

  - <off>	ADR <- ADR - off.
  		off is a hexadecimal number

  !		make instruction at ADR.
  		stop execution if not possible to create instruction (or rollback safe execution)

  #2		make 2-byte data item at ADR
  		stop execution if not possible to create instruction (or rollback safe execution)

  #4		make 4-byte data item at ADR
  		stop execution if not possible to create instruction (or rollback safe execution)

  &		follow data reference (ADR <- dref(ADR))
		For example, if instruction at ADR is

		  ADR:	push	offset somedata

		then ADR <- address of somedata
		if the current instruction at ADR doesn't refer to data,
		then stop execution or rollback safe execution.

  ^		follow code reference (ADR <- cref(ADR))
		For example, if instruction at ADR is

		  ADR:	call	somefunc

		then ADR <- address of somefunc
		if the current instruction at ADR doesn't refer to code,
		then stop execution or rollback safe execution.

  *0c
  *0d
  *1c
  *1d
  		make offset at ADR. general format is
			*<opnum><type>
		where opnum (operand number) is '0' or '1',
		type is 'c' for cs or 'd' for ds.

  / <name>	stop execution - we have found main() function. It is at ADR.
  		Its name follows '/' sign. If the name is not specified,
		its taken as '_main'.

  ? <byte> ... ;
  		Conditional.
		Test a byte at ADR. If it is equal to <byte> (hexadecimal),
		then continue execution. Otherwise skip ... part and jump
		to position after ';'.
		The ellipsis ... represents a sequence of any other symbols
		here. Conditionals can't be included in each other.

  ~<sigfile> / <+off> <funcname> ~ ... ;
  		Apply a signature file at ADR-<off>.
		If the specified <funcname> is found at ADR, then continue
		execution. Otherwise jump to execution position after ';'.

		sigfile - name of signature file to apply.
			  default: first signature file specified in -l switch
			  if sigfile == "-" then no signature file is applied,
			  only the <funcname> is tested.

		off	- offset from ADR. Must be hexadecimal 4-digit number
			  preceded by + sign.
			  default: 0

		funcname - name of function to compare.
			  default: WINMAIN

		For example, the shortest form is:

			~/~ ... ;

		This will apply the first signature to ADR and test a name
		appeared at ADR - it should be equal to WINMAIN.

  [mainname]	MAIN     <- ADR
  		MAINNAME <- mainname
		Remember possible main() function address and name.
		Default main() name is WINMAIN.

  ( ... )	Switch to safe mode of execution. In this mode the execution
		is not stopped if something went wrong (can't convert to
		instruction, for example). In this case we jump to symbol
		after ')' and set FLAG to 0.
		Otherwise (if everything went ok), set FLAG to 1 when PTR is
		at ')'.

  ?? ... ;	Test FLAG. If it is set (equal to 1), then continue execution.
  		Otherwise jump to symbol after ';'.
		Conditionals can't be included in each other.

  @sigfile@     plan to apply a signature file

  $idcfile$     execute an idc file

  Conditional semicolons (';') may be omitted.

IDC scripts
-----------

The 'idcfile' parameter mentioned above can be specified in three different ways:

  - plain file name with or without the .idc extension. If the extension is missing,
    IDA will add it. This method will lead to the execution of the main() function
    in the specified file. The file will be looked up in the IDC subdirectory.

  - filename/funcname[/arg1][/arg2][/argn...]
    This form allows you to specify the function name to be executed along with
    optional extra function arguments (the '[' and ']' characters above are not
    part of the syntax, they are used to show that the arguments are optional).
    The function must be declared the following way:

        static funcname(ADR[, arg1][, arg2][, argn...])
        {
          ....
          return ADR;
        }

    In other words, IDA will pass the current address as the first input argument,
    then the optional extra arguments (as strings), and will expect the function
    to return the modified current address.

  - IDC statements can be used instead of a file name. IDA will detect this
    by the presence of a semicolon in the file name and directly execute
    the statements

For the scripts invoked from startup signatures, IDA temporarily defines some
helper IDC functions. Below is the list:

// Set operating system type (analog of o= from above)
void SetOstype(long ostype);

// Set application type (analog of a= from above)
void SetApptype(long apptype);

// Set compiler id (analog of c= from above)
success SetCompilerId(long apptype);

// Apply secondary startup signature. If there is a match, the startup hints will
// be processed.
success ApplyStartupSig(ea, signame);

// Apply a signature to one address. If there is a match, recognized functions
// will be renamed.
// Returns: one of LIBFUNC_... constants
long ApplySigTo(ea, signame);
#define LIBFUNC_FOUND   0               // ok, library function is found
#define LIBFUNC_NONE    1               // no, this is not a library function
#define LIBFUNC_DELAY   2               // no decision because of lack of infor»

// Set list of optional signatures. Signature names are separated with slashes.
void SetOptionalSigs(string signature_names);

// Set the main function
void SetMainFunc(ea, name)

// Clear list of planned signature files
void ResetPlannedSigs();

// Plan to load a signature. This function is different from ApplySig(): it does
// not immediately plan to load but adds the signature name in an internal list.
// This list can be cleared with ResetPlannedSigs() is necessary.
void AddPlannedSig(string signame);

Examples
--------

	Please note that I give examples of most sophisticated usage of
	-l switch. Usually you don't need it.

-------------------------
plb -a -lo=1:a=84:l=bc31tvd/bc31cls:bc31rtd:m=+EF^/  bcc\1.01\C0C.OBJ exe_bc31

input file:	bcc\1.01\C0C.OBJ
output file:	exe_bc31.pat
		the output file should exist.
		we will append to it.
-l switch:
	OS type is MS DOS		(o=1)
	Application: 16 bit program	(a=84)
	Optional signatures: bc31tvd.sig
			     bc31cls.sig
	Automatically apply: bc31rtd.sig
	main() hints:
		add 0xEF to entry point of executable
		follow code reference (there is 'call' instruction there)
		main() function is here, its name is _main


-------------------------
echo -lo=2:a=84:bh16rwin:l=bh16cls/bh16owl/bh16ocf/bh16dbe>bh.tmp
plb -a @bh.tmp -lm=+AF^[]~/~+16^/ C0WC.OBJ  ne_bh.pat


input file:	C0WC.OBJ
output file:	ne_bh.pat
		the output file should exist.
		we will append to it.
-l switch:
	OS type is MS Windows		(o=2)
	Application: 16 bit program	(a=84)
	Automatically apply: bh16rwin
	Optional signatures: bh16cls
			     bh16owl
			     bh16ocf
			     bh16dbe
	main() hints:
 +AF		add 0xAF to entry point of executable
 ^		follow code reference (there is 'call' instruction there)
 []		remember the current address as possible WINMAIN address
 ~/~		apply bc16rwin.sig to the current address. Test for WINMAIN
 		name. If don't match, then stop - WINMAIN is here (because
		we saved it with [] operator). If name matches, then continue.
		(it is likely that EasyWin program is here)
 +16		add 16 to the current address (ADR)
 ^		follow the code reference (there is a 'call' instruction there)
 /		main() function is here, its name is _main

-------------------------
