fixup.hpp File Reference

Functions that deal with fixup information. More...

Classes
struct	fixup_data_t
struct	fixup_handler_t
	Implements the core behavior of a custom fixup. More...
struct	fixup_info_t
	Collect fixup records for the specified range. More...

Macros
#define	FIXUPF_REL   0x0001
	fixup is relative to the linear address `base'. More...
#define	FIXUPF_EXTDEF   0x0002
	target is a location (otherwise - segment). More...
#define	FIXUPF_UNUSED   0x0004
	fixup is ignored by IDA More...
#define	FIXUPF_CREATED   0x0008
	fixup was not present in the input file
#define	FIXUPF_LOADER_MASK   0xF0000000
	additional flags. More...
#define	FHF_VERIFY   0x0001
	verify that the value fits into WIDTH bits. More...
#define	FHF_CODE   0x0002
	verify that ITEM_EA in std_apply() points to an instruction. More...
#define	FHF_FORCE_CODE   0x0004
	if ITEM_EA in std_apply() points to an unknown item, then convert it to code. More...
#define	FHF_ABS_OPVAL   0x0008
	create absolute refinfo in std_apply() because the operand also has the absolute value (usually for o_near operands)
#define	FHF_SIGNED   0x0010
	the operand value is signed. More...
Fixup standard types
#define	FIXUP_OFF8   13
	8-bit offset
#define	FIXUP_OFF16   1
	16-bit offset
#define	FIXUP_SEG16   2
	16-bit base–logical segment base (selector)
#define	FIXUP_PTR16   3
	32-bit long pointer (16-bit base:16-bit offset)
#define	FIXUP_OFF32   4
	32-bit offset
#define	FIXUP_PTR32   5
	48-bit pointer (16-bit base:32-bit offset)
#define	FIXUP_HI8   6
	high 8 bits of 16bit offset
#define	FIXUP_HI16   7
	high 16 bits of 32bit offset
#define	FIXUP_LOW8   8
	low 8 bits of 16bit offset
#define	FIXUP_LOW16   9
	low 16 bits of 32bit offset
#define	V695_FIXUP_VHIGH   10
	obsolete
#define	V695_FIXUP_VLOW   11
	obsolete
#define	FIXUP_OFF64   12
	64-bit offset
#define	FIXUP_OFF8S   14
	8-bit signed offset
#define	FIXUP_OFF16S   15
	16-bit signed offset
#define	FIXUP_OFF32S   16
	32-bit signed offset
#define	FIXUP_CUSTOM   0x8000
	start of the custom types range

Typedefs
typedef uint16	fixup_type_t
	Fixup information structure. More...
typedef qvector< fixup_info_t >	fixups_t

Functions
THREAD_SAFE bool	is_fixup_custom (fixup_type_t type)
	Is fixup processed by processor module?
idaman bool ida_export	get_fixup (fixup_data_t *fd, ea_t source)
	Get fixup information.
bool	exists_fixup (ea_t source)
	Check that a fixup exists at the given address.
idaman void ida_export	set_fixup (ea_t source, const fixup_data_t &fd)
	Set fixup information. More...
idaman void ida_export	del_fixup (ea_t source)
	Delete fixup information.
idaman const fixup_handler_t *ida_export	get_fixup_handler (fixup_type_t type)
	Get handler of standard or custom fixup.
idaman bool ida_export	apply_fixup (ea_t item_ea, ea_t fixup_ea, int n, bool is_macro)
	Use fixup information for an address. More...
idaman uval_t ida_export	get_fixup_value (ea_t ea, fixup_type_t type)
	Get the operand value. More...
idaman bool ida_export	patch_fixup_value (ea_t ea, const fixup_data_t &fd)
	Patch the fixup bytes. More...
idaman const char *ida_export	get_fixup_desc (qstring *buf, ea_t source, const fixup_data_t &fd)
	Get FIXUP description comment.
idaman int ida_export	calc_fixup_size (fixup_type_t type)
	Calculate size of fixup in bytes (the number of bytes the fixup patches) More...
idaman bool ida_export	get_fixups (fixups_t *out, ea_t ea, asize_t size)
bool	contains_fixups (ea_t ea, asize_t size)
	Does the specified address range contain any fixup information?
idaman void ida_export	gen_fix_fixups (ea_t from, ea_t to, asize_t size)
	Relocate the bytes with fixup information once more (generic function). More...
idaman bool ida_export	handle_fixups_in_macro (refinfo_t *ri, ea_t ea, fixup_type_t other, uint32 macro_reft_and_flags)
	Handle two fixups in a macro. More...
Enumerate addresses with fixup information:
Get the first address with fixup information Returns the first address with fixup information, or BADADDR
idaman ea_t ida_export	get_first_fixup_ea (void)
idaman ea_t ida_export	get_next_fixup_ea (ea_t ea)
	Find next address with fixup information. More...
idaman ea_t ida_export	get_prev_fixup_ea (ea_t ea)
	Find previous address with fixup information. More...
std_get_value()
This internal function takes Tuning options to determine how to get the operand value. It is opposite in meaning to the std_patch_value(). 1) it gets the fixup_handler_t::size bytes at the given address, 2) it shifts the result left by fixup_handler_t::shift bits, 3) it returns the rightmost fixup_handler_t::width bits as a signed value. In details: b) size = 4, width = 28, shift = 2 it gets 4 bytes from the fixup address (the branch insn) then it shifts this dword left by 2 bits (shift=2) then the result is masked with 0xFFFFFFF (width=28) e.g. 0x10000017 the insn 0x4000005C the unshifted value 0x0000005C the masked result
idaman fixup_type_t ida_export	register_custom_fixup (const fixup_handler_t *cfh)
	Register a new custom fixup. More...
idaman bool ida_export	unregister_custom_fixup (fixup_type_t type)
	Unregister a new custom fixup format. More...
idaman fixup_type_t ida_export	find_custom_fixup (const char *name)
	Get id of a custom fixup handler. More...

Detailed Description

Functions that deal with fixup information.

A loader should setup fixup information using set_fixup().

Typedef Documentation

fixup_type_t

typedef uint16 fixup_type_t

Fixup information structure.

see Types of fixups

Function Documentation

set_fixup()

idaman void ida_export set_fixup	(	ea_t	source,
		const fixup_data_t &	fd
	)

Set fixup information.

You should fill fixup_data_t and call this function and the kernel will remember information in the database.

Parameters

source	the fixup source address, i.e. the address modified by the fixup
fd	fixup data

get_next_fixup_ea()

idaman ea_t ida_export get_next_fixup_ea

(

ea_t

ea

)

Find next address with fixup information.

Parameters

ea	current address

Returns

the next address with fixup information, or BADADDR

get_prev_fixup_ea()

idaman ea_t ida_export get_prev_fixup_ea

(

ea_t

ea

)

Find previous address with fixup information.

Parameters

ea	current address

Returns

the previous address with fixup information, or BADADDR

apply_fixup()

idaman bool ida_export apply_fixup	(	ea_t	item_ea,
		ea_t	fixup_ea,
		int	n,
		bool	is_macro
	)

Use fixup information for an address.

This function converts item_ea flags to offsets/segments. For undefined bytes, you may set item_ea == fixup_ea. In this case this function will create an item (byte, word, dword) there.

Parameters

item_ea	start address of item to modify
fixup_ea	address of fixup record
n	0..UA_MAXOP-1 operand number, OPND_ALL one of the operands
is_macro	is the instruction at 'item_ea' a macro? if yes, then partial fixups (HIGH, LOW) won't be applied

Return values

false	no fixup at fixup_ea or it has FIXUPF_UNUSED flag
true	ok, the fixup information was applied

get_fixup_value()

idaman uval_t ida_export get_fixup_value	(	ea_t	ea,
		fixup_type_t	type
	)

Get the operand value.

This function get fixup bytes from data or an instruction at `ea' and convert them to the operand value (maybe partially). It is opposite in meaning to the `patch_fixup_value()`. For example, FIXUP_HI8 read a byte at `ea' and shifts it left by 8 bits, or AArch64's custom fixup BRANCH26 get low 26 bits of the insn at `ea' and shifts it left by 2 bits. This function is mainly used to get a relocation addend.

Parameters

ea	address to get fixup bytes from, the size of the fixup bytes depends on the fixup type.

See also

fixup_handler_t::size

Parameters

type	fixup type

Return values

operand

value

patch_fixup_value()

idaman bool ida_export patch_fixup_value	(	ea_t	ea,
		const fixup_data_t &	fd
	)

Patch the fixup bytes.

This function updates data or an instruction at `ea' to the fixup bytes. For example, FIXUP_HI8 updates a byte at `ea' to the high byte of `fd->off', or AArch64's custom fixup BRANCH26 updates low 26 bits of the insn at `ea' to the value of `fd->off' shifted right by 2.

Parameters

ea	address where data are changed, the size of the changed data depends on the fixup type.

See also

fixup_handler_t::size

Parameters

fd	fixup data

Return values

false

the fixup bytes do not fit (e.g. `fd->off' is greater than 0xFFFFFFC for BRANCH26). The database is changed even in this case.

calc_fixup_size()

idaman int ida_export calc_fixup_size

(

fixup_type_t

type

)

Calculate size of fixup in bytes (the number of bytes the fixup patches)

Return values

-1	means error

register_custom_fixup()

idaman fixup_type_t ida_export register_custom_fixup

(

const fixup_handler_t *

cfh

)

Register a new custom fixup.

This function must be called by a processor module or plugin, but not by a file loader. File loaders should use find_custom_fixup() function to find the handler created by the processor module.

Returns

id of the new custom fixup handler with FIXUP_CUSTOM bit set or 0 (e.g. when the custom fixup handler with the same name was already registered).

unregister_custom_fixup()

idaman bool ida_export unregister_custom_fixup

(

fixup_type_t

type

)

Unregister a new custom fixup format.

Should be called by the processor module before the database gets closed.

find_custom_fixup()

idaman fixup_type_t ida_export find_custom_fixup

(

const char *

name

)

Get id of a custom fixup handler.

Parameters

name	name of the custom fixup handler

Returns

id with FIXUP_CUSTOM bit set or 0

gen_fix_fixups()

idaman void ida_export gen_fix_fixups	(	ea_t	from,
		ea_t	to,
		asize_t	size
	)

Relocate the bytes with fixup information once more (generic function).

This function may be called from loader_t::move_segm() if it suits the goal. If loader_t::move_segm is not defined then this function will be called automatically when moving segments or rebasing the entire program. Special parameter values (from = BADADDR, size = 0, to = delta) are used when the function is called from rebase_program(delta).

handle_fixups_in_macro()

idaman bool ida_export handle_fixups_in_macro	(	refinfo_t *	ri,
		ea_t	ea,
		fixup_type_t	other,
		uint32	macro_reft_and_flags
	)

Handle two fixups in a macro.

We often combine two instruction that load parts of a value into one macro instruction. For example:

ARM:   ADRP  X0, #var@PAGE
       ADD   X0, X0, #var@PAGEOFF  --> ADRL X0, var
MIPS:  lui   $v0, %hi(var)
       addiu $v0, $v0, %lo(var)    --> la   $v0, var

When applying the fixups that fall inside such a macro, we should convert them to one refinfo. This function does exactly that. It should be called from the apply() callback of a custom fixup.

Returns

success ('false' means that RI was not changed)