-- (c) Copyright - See License.txt

--

-- Euphoria 4.0

-- Machine Level Programming (386/486/Pentium)

--****

-- === safe.e

--

-- This is a slower DEBUGGING VERSION of machine.e

--

-- How To Use This File:

--

-- 1. If your program doesn't already include machine.e add:

-- include std/machine.e

-- to your main .ex[w][u] file at the top.

--

-- 2. To turn debug version on, issue

--

-- with define SAFE

--

-- in your main program, before the statement including machine.e.

--

-- 3. If necessary, call register_block(address, length, memory_protection) to add additional

-- "external" blocks of memory to the safe_address_list. These are blocks

-- of memory that are safe to use but which you did not acquire

-- through Euphoria's allocate(), allocate_data(), allocate_code() or memory_protect(). Call

-- unregister_block(address) when you want to prevent further access to

-- an external block.

--

-- 4. Run your program. It might be 10x slower than normal but it's

-- worth it to catch a nasty bug.

--

-- 5. If a bug is caught, you will hear some "beep" sounds.

-- Press Enter to clear the screen and see the error message.

-- There will be a "divide by zero" traceback in ex.err

-- so you can find the statement that is making the illegal memory access.

--

-- 6. To switch between normal and debug versions, simply comment in or out the

-- "with define SAFE" directive. In means debugging and out means normal.

-- Alternatively, you can use -D SAFE as a switch on the command line (debug) or not (normal).

--

-- 7. The older method of switching files and renaming them //**no longer works**//. machine.e conditionally includes safe.e.

--

-- This file is equivalent to machine.e, but it overrides the built-in

-- routines:

-- poke, peek, poke4, peek4s, peek4u, call, mem_copy, and mem_set

-- and it provides alternate versions of:

-- allocate, free

--

-- Your program will only be allowed to read/write areas of memory

-- that it allocated (and hasn't freed), as well as areas in low memory

-- that you list below, or add dynamically via register_block().

namespace safe

include std/error.e

include std/win32/sounds.e

end ifdef

public include std/memconst.e

public include std/machine.e as machine

end ifdef

-- Some parameters you may wish to change:

--**

-- Define block checking policy.

--

-- Comments:

--

-- If this integer is 1, (the default), check all blocks for edge corruption after each

-- [[:call]](), [[:c_proc]]() or [[:c_func]]().

-- To save time, your program can turn off this checking by setting check_calls to 0.

--**

-- Determine whether to flag accesses to remote memory areas.

--

-- Comments:

--

-- If this integer is 1 (the default under //WIN32//), only check for references to the

-- leader or trailer areas just outside each registered block, and don't complain about

-- addresses that are far out of bounds (it's probably a legitimate block from another source)

--

-- For a stronger check, set this to 0 if your program will never read/write an

-- unregistered block of memory.

--

-- On //WIN32// people often use unregistered blocks.

-- Constants that tell us what we are about to try to do: read, write or execute memory.

-- They should be distinct from PERM_EXEC, etc...

-- These are not permission constants.

-- Internal types for understanding more than type-checking:

-- internal address

-- addresses used for passing to and getting from low level machine_func calls and to a few

-- local only routines.

end type

-- external address

-- addresses used for passing to and getting from high level functions in machine.e and

-- public functions declared here.

end type

-- Include the starting address and length of any

-- acceptable areas of memory for peek/poke here.

-- Set allocation number to 0.

-- This symbol is *only* available from std/machine.e when SAFE is defined.

with type_check

-- machine_proc(M_SLEEP, 3)

-- biggest address on a 32-bit machine

-- biggest address accessible to 16-bit real mode

end type

end type

-- a 32-bit non-null machine address

end type

-- protected mode far address {seg, offset}

end type

-- a legal low machine address

end type

sequence l

end if

end type

-- Return true if /action/ is not allowed when memory has /protection/

else

end if

end function

-- Return true if /action/ is allowed when memory has /protection/

end function

-- is it ok to read/write all addresses from start to start+len-1?

-- Note: This routine is available from std/machine.e *only* when SAFE

-- is defined.

atom block_start, block_upper, upper

sequence block

end if

-- search the list of safe memory blocks:

-- addresses are considered safe as long as

-- they aren't in any block's border zone and

-- if they are in a block, the action is permitted

-- for that block's protection

end if

-- an allocated block with a border area

start < block_start) or

(start >= block_upper and

start < block_upper + BORDER_SPACE) then

upper <= block_start) or

(upper > block_upper and

upper < block_upper + BORDER_SPACE) then

upper > block_upper + BORDER_SPACE then

end if

end if

(block_start <= upper and upper <= block_upper) )

and

does_not_permit( block[BLOCK_PROT], action )

then

end if

else

-- addresses are considered safe as long as

-- they are inside an allocated or registered block

-- whose protection permits the current action.

-- move block i to the top and move 1..i-1 down

-- common case, subscript is faster than slice:

else

end if

end if

else

end if

end if

end if

end if

else

end if

end function

-- Terminate with a message.

-- makes warning beeps first so you can see what's happening on the screen

sound()

end ifdef

sound(0)

end ifdef

-- show address in decimal and hex

end function

without warning &= (override)

-- safe version of peek

integer len

atom a

else

end if

else

end if

end function

-- safe version of peeks

integer len

atom a

else

end if

else

end if

end function

-- safe version of peek

integer len

atom a

else

end if

else

end if

end function

-- safe version of peek

integer len

atom a

else

end if

else

end if

end function

-- safe version of peek4s

integer len

atom a

else

end if

else

end if

end function

-- safe version of peek4u

integer len

atom a

else

end if

else

end if

end function

-- safe version of peek_string

integer len

else

end if

else

end if

end function

-- safe version of poke

integer len

else

end if

else

end if

-- safe version of poke2

integer len

else

end if

else

end if

-- safe version of poke4

integer len

else

end if

else

end if

-- safe mem_copy

else

end if

-- safe mem_set

else

end if

atom allocation_num

-- display byte at memory location m

integer c

else

else

end if

end if

-- display a corrupted block and die

integer len, id, bad, p

atom start

-- check pre-block

end if

end if

-- show whole block

else

-- first part of block

-- last part of block

end if

-- check post-block

end if

end if

-- Check all allocated blocks for corruption of the leader and trailer areas.

integer n

ext_addr a

sequence block

-- a block that we allocated

eu:peek({a-BORDER_SPACE, BORDER_SPACE})) then

eu:peek({a+n, BORDER_SPACE})) then

end if

end if

-- safe call - machine code must start in block that we own

end if

else

end if

end if

object r

end if

end function

-- register an externally-acquired block of memory as being safe to use

end if

-allocation_num,memory_protection})

-- remove an external block of memory from the safe address list

end if

safe_address_list[i+1..$]

end if

ext_addr eaddr

-- set up an allocated block so we can check it for corruption

end if

end function

-- Internal use of the library only. free() calls this. It works with

-- only atoms and in the unSAFE implementation is different.

-- free address a - make sure it was allocated

int_addr ia

-- check pre and post block areas

end if

end if

ifdef WINDOWS then

if dep_works() then

eu:c_func( VirtualFree_rid, { ia, n, MEM_RELEASE } )

else

eu:machine_proc(M_FREE, ia)

end if

elsedef

eu:machine_proc(M_FREE, ia)

end ifdef

elsedef

"THAT WAS ALLOCATED BY allocate_protect()!")

end if

end ifdef

-- remove it from list

end if

end if

-- Returns 1 if the DEP executing data only memory would cause an exception

return DEP_really_works

elsedef

end ifdef

end function

export atom VirtualFree_rid

integer free_succeeded

sequence block

end if

end if

end if

if dep_works() then

free_succeeded = c_func( VirtualFree_rid,

{ addr-BORDER_SPACE, size*wordsize, MEM_RELEASE } )

return

end if

end ifdef

-- Shawn's custom stuff:

Total memory allocations %10d

Total memory allocated %10dB""",

{ length(safe_address_list), tm } )

end function

end function

end function