p_wcle.cpp

UPX 源代码

/* p_wcle.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 "lefile.h"
#include "p_wcle.h"
#include "linker.h"

static const
#include "stub/i386-dos32.watcom.le.h"

#define LEOF_READ       (1<<0)
#define LEOF_WRITE      (1<<1)
#define LEOF_EXEC       (1<<2)
#define LEOF_PRELOAD    (1<<6)
#define LEOF_HUGE32     (1<<13)

#define IOT(x,y)        iobject_table[x].y
#define OOT(x,y)        oobject_table[x].y

#define LE_STUB_EDI     (1)

#ifdef TESTING
# define dputc(x,y)     do { if (opt->debug.debug_level) putc(x,y); } while (0)
# define Opt_debug      opt->debug.debug_level
#else
# define dputc(x,y)     ((void)0)
# define Opt_debug      0
#endif

#define my_base_address reserved
#define objects         ih.object_table_entries
#define pages           ih.memory_pages
#define mps             ih.memory_page_size
#define opages          oh.memory_pages


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

const int *PackWcle::getCompressionMethods(int method, int level) const
{
    return Packer::getDefaultCompressionMethods_le32(method, level);
}


const int *PackWcle::getFilters() const
{
    static const int filters[] = {
        0x26, 0x24, 0x49, 0x46, 0x16, 0x13, 0x14, 0x11,
        FT_ULTRA_BRUTE, 0x25, 0x15, 0x12,
    FT_END };
    return filters;
}


Linker* PackWcle::newLinker() const
{
    return new ElfLinkerX86;
}


void PackWcle::buildLoader(const Filter *ft)
{
    // prepare loader
    initLoader(stub_i386_dos32_watcom_le, sizeof(stub_i386_dos32_watcom_le));
    addLoader("IDENTSTR,WCLEMAIN",
              ph.first_offset_found == 1 ? "WCLEMAIN02" : "",
              "WCLEMAIN03,UPX1HEAD,WCLECUTP", NULL);

    // fake alignment for the start of the decompressor
    linker->defineSymbol("WCLECUTP", 0x1000);

    addLoader(getDecompressorSections(), "WCLEMAI2", NULL);
    if (ft->id)
    {
        assert(ft->calls > 0);
        addLoader(ft->addvalue ? "WCCTTPOS" : "WCCTTNUL", NULL);
        addFilter32(ft->id);
    }
#if 1
    // FIXME: if (has_relocation)
    {
        addLoader("WCRELOC1,RELOC320",
                  big_relocs ? "REL32BIG" : "",
                  "RELOC32J",
                  NULL
                 );
    }
#endif
    addLoader(has_extra_code ? "WCRELSEL" : "",
              "WCLEMAI4",
              NULL
             );
}


/*************************************************************************
// util
**************************************************************************/

void PackWcle::handleStub(OutputFile *fo)
{
    if (fo && !opt->watcom_le.le)
        Packer::handleStub(fi,fo,le_offset);
}


bool PackWcle::canPack()
{
    if (!LeFile::readFileHeader())
        return false;
    return true;
}


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

// IDEA: as all the entries go into object #1, I could create bundles with 255
// elements (of course I still have to handle empty bundles)

void PackWcle::encodeEntryTable()
{
    unsigned count,object,n;
    upx_byte *p = ientries;
    n = 0;
    while (*p)
    {
        count = *p;
        n += count;
        if (p[1] == 0) // unused bundle
            p += 2;
        else if (p[1] == 3) // 32-bit bundle
        {
            object = get_le16(p+2)-1;
            set_le16(p+2,1);
            p += 4;
            for (; count; count--, p += 5)
                set_le32(p+1,IOT(object,my_base_address) + get_le32(p+1));
        }
        else
            throwCantPack("unsupported bundle type in entry table");
    }

    //if (Opt_debug) printf("%d entries encoded.\n",n);
    UNUSED(n);

    soentries = ptr_diff(p, ientries) + 1;
    oentries = ientries;
    ientries = NULL;
}


void PackWcle::readObjectTable()
{
    LeFile::readObjectTable();

    // temporary copy of the object descriptors
    iobject_desc.alloc(objects*sizeof(*iobject_table));
    memcpy(iobject_desc,iobject_table,objects*sizeof(*iobject_table));

    unsigned ic,jc,virtual_size;

    for (ic = jc = virtual_size = 0; ic < objects; ic++)
    {
        jc += IOT(ic,npages);
        IOT(ic,my_base_address) = virtual_size;
        virtual_size += (IOT(ic,virtual_size)+mps-1) &~ (mps-1);
    }
    if (pages != jc)
        throwCantPack("bad page number");
}


void PackWcle::encodeObjectTable()
{
    unsigned ic,jc;

    oobject_table = new le_object_table_entry_t[soobject_table = 2];
    memset(oobject_table,0,soobject_table * sizeof(*oobject_table));

    // object #1:
    OOT(0,base_address) = IOT(0,base_address);

    ic = IOT(objects-1,my_base_address)+IOT(objects-1,virtual_size);
    jc = pages*mps+sofixups+1024;
    if (ic < jc)
        ic = jc;

    unsigned csection = (ic + ph.overlap_overhead + mps-1) &~ (mps-1);

    OOT(0,virtual_size) = csection + mps;
    OOT(0,flags) = LEOF_READ|LEOF_EXEC|LEOF_HUGE32|LEOF_PRELOAD;
    OOT(0,pagemap_index) = 1;
    OOT(0,npages) = opages;

    // object #2: stack
    OOT(1,base_address) = (OOT(0,base_address)
                                      +OOT(0,virtual_size)+mps-1) & ~(mps-1);
    OOT(1,virtual_size) = mps + getDecompressorWrkmemSize();
    OOT(1,flags) = LEOF_READ|LEOF_HUGE32|LEOF_WRITE;
    OOT(1,pagemap_index) = 1;

    oh.init_cs_object = 1;
    oh.init_eip_offset = neweip;
    oh.init_ss_object = 2;
    oh.init_esp_offset = OOT(1,virtual_size);
    oh.automatic_data_object = 2;
}


void PackWcle::encodePageMap()
{
    opm_entries = new le_pagemap_entry_t[sopm_entries = opages];
    for (unsigned ic = 0; ic < sopm_entries; ic++)
    {
        opm_entries[ic].l = (unsigned char) (ic+1);
        opm_entries[ic].m = (unsigned char) ((ic+1)>>8);
        opm_entries[ic].h = 0;
        opm_entries[ic].type = 0;
    }
}


void PackWcle::encodeFixupPageTable()
{
    unsigned ic;
    ofpage_table = new unsigned[sofpage_table = 1 + opages];
    for (ofpage_table[0] = ic = 0; ic < opages; ic++)
        set_le32(ofpage_table+ic+1,sofixups-FIXUP_EXTRA);
}


void PackWcle::encodeFixups()
{
    ofixups = new upx_byte[sofixups = 1*7 + FIXUP_EXTRA];
    memset(ofixups,0,sofixups);
    ofixups[0] = 7;
    set_le16(ofixups+2,(LE_STUB_EDI + neweip) & (mps-1));
    ofixups[4] = 1;
}


void PackWcle::preprocessFixups()
{
    big_relocs = 0;

    unsigned ic,jc;

    Array(unsigned, counts, objects+2);
    countFixups(counts);

    for (ic = jc = 0; ic < objects; ic++)
        jc += counts[ic];

    if (jc == 0)
    {
        // FIXME: implement this
        throwCantPack("files without relocations are not supported");
    }

    ByteArray(rl, jc);
    ByteArray(srf, counts[objects+0]+1);
    ByteArray(slf, counts[objects+1]+1);

    upx_byte *selector_fixups = srf;
    upx_byte *selfrel_fixups = slf;
    unsigned rc = 0;

    upx_byte *fix = ifixups;
    for (ic = jc = 0; ic < pages; ic++)
    {
        while ((unsigned)(fix - ifixups) < get_le32(ifpage_table+ic+1))
        {
            const int fixp2 = get_le16_signed(fix+2);
            unsigned value;

            switch (*fix)
            {
                case 2:       // selector fixup
                    if (fixp2 < 0)
                    {
                        // cross page selector fixup
                        dputc('S',stdout);
                        fix += 5;
                        break;
                    }
                    dputc('s',stdout);
                    memcpy(selector_fixups,"\x8C\xCB\x66\x89\x9D",5); // mov bx, cs ; mov [xxx+ebp], bx
                    if (IOT(fix[4]-1,flags) & LEOF_WRITE)
                        selector_fixups[1] = 0xDB; // ds
                    set_le32(selector_fixups+5,jc+fixp2);
                    selector_fixups += 9;
                    fix += 5;
                    break;
                case 5:       // 16-bit offset
                    if ((unsigned)fixp2 < 4096 && IOT(fix[4]-1,my_base_address) == jc)
                        dputc('6',stdout);
                    else
                        throwCantPack("unsupported 16-bit offset relocation");
                    fix += (fix[1] & 0x10) ? 9 : 7;
                    break;
                case 6:       // 16:32 pointer
                    if (fixp2 < 0)
                    {
                        // cross page pointer fixup
                        dputc('P',stdout);
                        fix += (fix[1] & 0x10) ? 9 : 7;
                        break;
                    }
                    dputc('p',stdout);
                    memcpy(iimage+jc+fixp2,fix+5,(fix[1] & 0x10) ? 4 : 2);
                    set_le32(rl+4*rc++,jc+fixp2);
                    set_le32(iimage+jc+fixp2,get_le32(iimage+jc+fixp2)+IOT(fix[4]-1,my_base_address));

                    memcpy(selector_fixups,"\x8C\xCA\x66\x89\x95",5);
                    if (IOT(fix[4]-1,flags) & LEOF_WRITE)
                        selector_fixups[1] = 0xDA; // ds
                    set_le32(selector_fixups+5,jc+fixp2+4);
                    selector_fixups += 9;
                    fix += (fix[1] & 0x10) ? 9 : 7;
                    break;
                case 7:       // 32-bit offset
                    if (fixp2 < 0)
                    {
                        fix += (fix[1] & 0x10) ? 9 : 7;
                        break;
                    }
                    //if (memcmp(iimage+jc+fixp2,fix+5,(fix[1] & 0x10) ? 4 : 2))
                    //    throwCantPack("illegal fixup offset");

                    // work around an pmwunlite bug: remove duplicated fixups
                    // FIXME: fix the other cases too
                    if (rc == 0 || get_le32(rl+4*rc-4) != jc+fixp2)
                    {
                        set_le32(rl+4*rc++,jc+fixp2);
                        set_le32(iimage+jc+fixp2,get_le32(iimage+jc+fixp2)+IOT(fix[4]-1,my_base_address));
                    }
                    fix += (fix[1] & 0x10) ? 9 : 7;
                    break;
                case 8:       // 32-bit self relative fixup
                    if (fixp2 < 0)
                    {
                        // cross page self relative fixup
                        dputc('R',stdout);
                        fix += (fix[1] & 0x10) ? 9 : 7;
                        break;
                    }
                    value = get_le32(fix+5);
                    if (fix[1] == 0)
                        value &= 0xffff;
                    set_le32(iimage+jc+fixp2,(value+IOT(fix[4]-1,my_base_address))-jc-fixp2-4);
                    set_le32(selfrel_fixups,jc+fixp2);
                    selfrel_fixups += 4;
                    dputc('r',stdout);
                    fix += (fix[1] & 0x10) ? 9 : 7;
                    break;
                default:
                    throwCantPack("unsupported fixup record");
            }
        }
        jc += mps;
    }

    // resize ifixups if it's too small
    if (sofixups < 1000)
    {
        delete[] ifixups;
        ifixups = new upx_byte[1000];
    }
    fix = optimizeReloc32 (rl,rc,ifixups,iimage,1,&big_relocs);
    has_extra_code = srf != selector_fixups;
    // FIXME: this could be removed if has_extra_code = false
    // but then we'll need a flag
    *selector_fixups++ = 0xC3; // ret
    memcpy(fix,srf,selector_fixups-srf); // copy selector fixup code
    fix += selector_fixups-srf;

    memcpy(fix,slf,selfrel_fixups-slf); // copy self-relative fixup positions
    fix += selfrel_fixups-slf;
    set_le32(fix,0xFFFFFFFFUL);
    fix += 4;

    sofixups = ptr_diff(fix, ifixups);
}


#define RESERVED 0x1000
void PackWcle::encodeImage(Filter *ft)
{
    // concatenate image & preprocessed fixups
    unsigned isize = soimage + sofixups;
    ibuf.alloc(isize);
    memcpy(ibuf,iimage,soimage);
    memcpy(ibuf+soimage,ifixups,sofixups);

    delete[] ifixups; ifixups = NULL;

    oimage.allocForCompression(isize, RESERVED+512);
    // prepare packheader