p_tos.cpp

UPX 源代码

/* p_tos.cpp --

   This file is part of the UPX executable compressor.

   Copyright (C) 1996-2007 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1996-2007 Laszlo Molnar
   All Rights Reserved.

   UPX and the UCL library are free software; you can redistribute them
   and/or modify them under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer              Laszlo Molnar
   <[e-mail]>          <[e-mail]>
 */


#include "conf.h"

#include "file.h"
#include "filter.h"
#include "packer.h"
#include "p_tos.h"
#include "linker.h"

static const
#include "stub/m68k-atari.tos.h"

//#define TESTING 1


/*************************************************************************
//
**************************************************************************/

#define FH_SIZE         sizeof(tos_header_t)

PackTos::PackTos(InputFile *f) :
    super(f)
{
    bele = &N_BELE_RTP::be_policy;
    COMPILE_TIME_ASSERT(FH_SIZE == 28);
}


const int *PackTos::getCompressionMethods(int method, int level) const
{
    bool small = ih.fh_text + ih.fh_data <= 256*1024;
    return Packer::getDefaultCompressionMethods_8(method, level, small);
}


const int *PackTos::getFilters() const
{
    return NULL;
}


Linker* PackTos::newLinker() const
{
    return new ElfLinkerM68k;
}


void PackTos::LinkerSymbols::LoopInfo::init(unsigned count_, bool allow_dbra)
{
    count = value = count_;
    if (count == 0)
        mode = LOOP_NONE;
    else if (count <= 65536 && allow_dbra)
    {
        mode = LOOP_DBRA;
        value -= 1;
        value &= 0xffff;
    }
    else if (count <= 65536)
    {
        mode = LOOP_SUBQ_W;
        value &= 0xffff;
    }
    else
        mode = LOOP_SUBQ_L;
}


unsigned PackTos::getDecomprOffset(int method, int small) const
{
    UNUSED(small);
    if (M_IS_NRV2B(method))
        return 2;   // FIXME: do not hardcode this value
    else if (M_IS_NRV2D(method))
        return 2;   // FIXME: do not hardcode this value
    else if (M_IS_NRV2E(method))
        return 2;   // FIXME: do not hardcode this value
    else if (M_IS_LZMA(method))
        return linker->getSectionSize("__mulsi3");
    else
        throwBadLoader();
    return 0;
}


void PackTos::buildLoader(const Filter *ft)
{
    assert(ft->id == 0);

    initLoader(stub_m68k_atari_tos, sizeof(stub_m68k_atari_tos));
    //linker->dumpSymbols();

    //
    // part 1a
    //

    addLoader("entry");

    if (symbols.up21_a6 <= 32767)
        addLoader("set_up21_a6.w");
    else if (symbols.up21_d4 <= 32767)
        addLoader("set_up21_d4.w");
    else
        addLoader("set_up21_d4.l");

    assert(symbols.loop1.count || symbols.loop2.count);
    if (symbols.loop1.count)
    {
        if (symbols.loop1.value <= 127)
            addLoader("loop1_set_count.b");
        else if (symbols.loop1.value <= 65535)
            addLoader("loop1_set_count.w");
        else
            addLoader("loop1_set_count.l");
        addLoader("loop1_label");
        addLoader(opt->small ? "loop1.small" : "loop1.fast");
        if (symbols.loop1.mode == symbols.LOOP_SUBQ_L)
            addLoader("loop1_subql");
        else if (symbols.loop1.mode == symbols.LOOP_SUBQ_W)
            addLoader("loop1_subqw");
        else if (symbols.loop1.mode == symbols.LOOP_DBRA)
            addLoader("loop1_dbra");
        else
            throwBadLoader();
    }
    if (symbols.loop2.count)
    {
        assert(symbols.loop2.mode == symbols.LOOP_DBRA);
        addLoader(opt->small ? "loop2.small" : "loop2.fast");
    }

    addLoader("copy_to_stack");

    if (M_IS_NRV2B(ph.method))
        addLoader("nrv2b.init");
    else if (M_IS_NRV2D(ph.method))
        addLoader("nrv2d.init");
    else if (M_IS_NRV2E(ph.method))
        addLoader("nrv2e.init");
    else if (M_IS_LZMA(ph.method))
        addLoader("lzma.init");
    else
        throwBadLoader();

    symbols.up31_d4 = symbols.up31_base_d4 + getDecomprOffset(ph.method, opt->small);
    symbols.up31_a6 = symbols.up31_base_a6 + getDecomprOffset(ph.method, opt->small);
    if (symbols.up31_a6 <= 32767)
        addLoader("jmp_decompressor_a6.w");
    else if (symbols.up31_d4 <= 32767)
        addLoader("jmp_decompressor_d4.w");
    else if (symbols.up31_a6 <= 65534)
        addLoader("jmp_decompressor_a6.w2");
    else
        addLoader("jmp_decompressor_d4.l");

    //
    // part 1b
    //

    addLoader("code_on_stack");

    addLoader("clear_dirty_bss");
    addLoader("loop3_label");
    addLoader(opt->small ? "loop3.small" : "loop3.fast");
    if (symbols.loop3.mode == symbols.LOOP_SUBQ_L)
        addLoader("loop3_subql");
    else if (symbols.loop3.mode == symbols.LOOP_SUBQ_W)
        addLoader("loop3_subqw");
    else if (symbols.loop3.mode == symbols.LOOP_DBRA)
        addLoader("loop3_dbra");
    else
        throwBadLoader();

    addLoader("flush_cache");
    addLoader("restore_stack");
#if 0
    addLoader("clear_dirty_stack");
#endif
    addLoader("start_program");

    addLoader("IDENTSTR,+40D,UPX1HEAD,CUTPOINT");

    //
    // part 2
    //

    if (M_IS_NRV2B(ph.method)) {
        addLoader(opt->small ? "nrv2b_8.small" : "nrv2b_8.fast");
    } else if (M_IS_NRV2D(ph.method)) {
        addLoader(opt->small ? "nrv2d_8.small" : "nrv2d_8.fast");
    } else if (M_IS_NRV2E(ph.method)) {
        addLoader(opt->small ? "nrv2e_8.small" : "nrv2e_8.fast");
    } else if (M_IS_LZMA(ph.method)) {
        addLoader("__mulsi3");
        addLoader(opt->small ? "lzma.small" : "lzma.fast");
        addLoader("lzma.finish");
    }
    else
        throwBadLoader();

    if (symbols.need_reloc)
        addLoader("reloc");

    assert(symbols.loop3.count);
    if (symbols.loop3.value <= 127)
        addLoader("loop3_set_count.b");
    else if (symbols.loop3.value <= 65535)
        addLoader("loop3_set_count.w");
    else
        addLoader("loop3_set_count.l");

    addLoader("jmp_stack");
}


/*************************************************************************
//
**************************************************************************/

/* flags for curproc->memflags */
/* also used for program headers fh_flag */
#define F_FASTLOAD      0x01        // don't zero heap
#define F_ALTLOAD       0x02        // OK to load in alternate ram
#define F_ALTALLOC      0x04        // OK to malloc from alt. ram
#define F_SMALLTPA      0x08        // used in MagiC: TPA can be allocated
                                    // as specified in the program header
                                    // rather than the biggest free memory
                                    // block
#define F_MEMFLAGS      0xf0        // reserved for future use
#define F_SHTEXT        0x800       // program's text may be shared

#define F_MINALT        0xf0000000  // used to decide which type of RAM to load in

#define F_ALLOCZERO     0x2000      // zero mem, for bugged (GEM...) programs

/* Bit in Mxalloc's arg for "don't auto-free this memory" */
#define F_KEEP          0x4000

#define F_OS_SPECIAL    0x8000      // mark as a special process

/* flags for curproc->memflags (that is, fh_flag) and also Mxalloc mode.  */
/* (Actually, when users call Mxalloc, they add 0x10 to what you see here) */
#define F_PROTMODE      0xf0        // protection mode bits
#define F_PROT_P        0x00        // no read or write
#define F_PROT_G        0x10        // any access OK
#define F_PROT_S        0x20        // any super access OK
#define F_PROT_PR       0x30        // any read OK, no write
#define F_PROT_I        0x40        // invalid page


/*************************************************************************
// util
//   readFileHeader() reads ih and checks for illegal values
//   checkFileHeader() checks ih for legal but unsupported values
**************************************************************************/

int PackTos::readFileHeader()
{
    fi->seek(0,SEEK_SET);
    fi->readx(&ih, FH_SIZE);
    if (ih.fh_magic != 0x601a)
        return 0;
    if (FH_SIZE + ih.fh_text + ih.fh_data + ih.fh_sym > (unsigned) file_size)
        return 0;
    return UPX_F_ATARI_TOS;
}


bool PackTos::checkFileHeader()
{
    const unsigned f = ih.fh_flag;
    //printf("flags: 0x%x, text: %d, data: %d, bss: %d, sym: %d\n", f, (int)ih.fh_text, (int)ih.fh_data, (int)ih.fh_bss, (int)ih.fh_sym);
    if ((ih.fh_text & 1) || (ih.fh_data & 1))
        throwCantPack("odd size values in text/data");
    if (f & F_OS_SPECIAL)
        throwCantPack("I won't pack F_OS_SPECIAL programs");
    if ((f & F_PROTMODE) > F_PROT_I)
        throwCantPack("invalid protection mode");
    if ((f & F_PROTMODE) != F_PROT_P)
    {
        if (opt->force < 1)
            throwCantPack("no private memory protection; use option '-f' to force packing");
    }
    if (f & F_SHTEXT)
    {
        if (opt->force < 1)
            throwCantPack("shared text segment; use option '-f' to force packing");
    }
#if 0
    // fh_reserved seems to be unused
    if (ih.fh_reserved != 0)
    {
        if (opt->force < 1)
            throwCantPack("reserved header field set; use option '-f' to force packing");
    }
#endif
    return true;
}


/*************************************************************************
// relocs
**************************************************************************/

// Check relocation for errors to make sure our loader can handle it.
static int check_relocs(const upx_byte *relocs, unsigned rsize, unsigned isize,
                        unsigned *nrelocs, unsigned *relocsize, unsigned *overlay)
{
    unsigned fixup = get_be32(relocs);
    unsigned last_fixup = fixup;
    unsigned i = 4;

    assert(isize >= 4);
    assert(fixup > 0);

    *nrelocs = 1;
    for (;;)
    {
        if (fixup & 1)              // must be word-aligned
            return -1;
        if (fixup + 4 > isize)      // too far
            return -1;
        if (i >= rsize)             // premature EOF in relocs
            return -1;
        unsigned c = relocs[i++];
        if (c == 0)                 // end marker
            break;
        else if (c == 1)            // increase fixup, no reloc
            fixup += 254;
        else if (c & 1)             // must be word-aligned
            return -1;
        else                        // next reloc is here
        {
            fixup += c;
            if (fixup - last_fixup < 4)     // overlapping relocation
                return -1;
            last_fixup = fixup;
            *nrelocs += 1;
        }
    }

    *relocsize = i;
    *overlay = rsize - i;
    return 0;
}


/*************************************************************************
//
**************************************************************************/

bool PackTos::canPack()
{
    if (!readFileHeader())
        return false;

    unsigned char buf[768];
    fi->readx(buf, sizeof(buf));
    checkAlreadyPacked(buf, sizeof(buf));

    if (!checkFileHeader())
        throwCantPack("unsupported header flags");
    if (file_size < 1024)