p_ps1.cpp

UPX 源代码

        }
        else
        {
            if (M_IS_LZMA(ph.method))
                addLoader(!foundBss ? "cdb.start.lzma" : "bss.cdb.start.lzma", "pad.code",
                          !foundBss ? "cdb.entry.lzma" : "bss.cdb.entry.lzma",
                          method, "cdb.lzma.cpr",
                          ih.tx_ptr & 0xffff ?  "dec.ptr" : "dec.ptr.hi",
                          "lzma.exec", NULL);
            else
            {
                assert(foundBss != true);
                addLoader("cdb.start", "pad.code", "cdb.entry",
                          ih.tx_ptr & 0xffff ?  "cdb.dec.ptr" : "cdb.dec.ptr.hi",
                          method,
                          sa_cnt ? sa_cnt > (0x10000 << 2) ? "memset.long" : "memset.short" : "",
                          "cdb.exit", NULL);
            }
        }
        addLoader("UPX1HEAD", "IDENTSTR", NULL);
    }
}

#define OPTYPE(x)     (((x) >> 13) & 0x7)
#define OPCODE(x)     (((x) >> 10) & 0x7)
#define REG1(x)       (((x) >> 5) & 0x1f)
#define REG2(x)       ((x) & 0x1f)

#define MIPS_IMM(a,b) ((((a) - (((b) & 0x8000) >> 15)) << 16) | (b))

// Type
#define REGIMM  1
#define STORE   5
// Op
#define LUI     7
#define ADDIU   1
#define SW      3

#define IS_LUI(a)     ((OPTYPE(a) == REGIMM && OPCODE(a) == LUI))
#define IS_ADDIU(a)   ((OPTYPE(a) == REGIMM && OPCODE(a) == ADDIU))
#define IS_SW_ZERO(a) ((OPTYPE(a) == STORE && OPCODE(a) == SW) && REG2(a) == 0)

#define BSS_CHK_LIMIT (18)

bool PackPs1::findBssSection()
{
    unsigned char reg;
    LE32 *p1 = (LE32 *)(ibuf + (ih.epc - ih.tx_ptr));

    if ((ih.epc - ih.tx_ptr + (BSS_CHK_LIMIT * 4)) > fdata_size)
        return false;

    // check 18 opcodes for sw zero,0(x)
    for (signed i = BSS_CHK_LIMIT; i >= 0; i--)
    {
        unsigned short op = p1[i] >> 16;
        if (IS_SW_ZERO(op))
        {
            // found! get reg (x) for bss_start
            reg = REG1(op);
            for (; i >= 0; i--)
            {
                bss_nfo *p = (bss_nfo *)&p1[i];
                unsigned short op1 = p->op1, op2 = p->op2;

                // check for la (x),bss_start
                if ((IS_LUI(op1) && REG2(op1) == reg) &&
                    (IS_ADDIU(op2) && REG1(op2) == reg))
                {
                    op1 = p->op3, op2 = p->op4;

                    // check for la (y),bss_end
                    if (IS_LUI(op1) && IS_ADDIU(op2))
                    {
                        // bss section info found!
                        bss_start = MIPS_IMM(p->hi1, p->lo1);
                        bss_end = MIPS_IMM(p->hi2, p->lo2);

                        if (0 < ALIGN_DOWN(bss_end - bss_start, 4u))
                        {
                            unsigned wkmem_sz = M_IS_LZMA(ph.method) ? 32768 : 800;
                            unsigned end_offs = ih.tx_ptr + fdata_size + overlap;
                            if (bss_end > (end_offs + wkmem_sz))
                                return isCon || (!isCon && M_IS_LZMA(ph.method));
                            else
                                return false;
                        }
                    }
                    else
                        return false;
                }
            }
        }
    }
    return false;
}


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

void PackPs1::pack(OutputFile *fo)
{
    ibuf.alloc(fdata_size);
    obuf.allocForCompression(fdata_size);
    const upx_byte *p_scan = ibuf + fdata_size;

    // read file
    fi->seek(PS_HDR_SIZE,SEEK_SET);
    fi->readx(ibuf,fdata_size);

    // scan EOF for 2048 bytes sector alignment
    // the removed space will secure in-place decompression
    while (!(*--p_scan)) { if (sa_cnt++ > (0x10000 << 5) || sa_cnt >= fdata_size - 1024) break; }

    if (sa_cnt > (0x10000 << 2))
        sa_cnt = ALIGN_DOWN(sa_cnt, 32u);
    else
        sa_cnt = ALIGN_DOWN(sa_cnt, 4u);

    // prepare packheader
    ph.u_len = (fdata_size - sa_cnt);
    ph.filter = 0;
    Filter ft(ph.level);

    // compress (max_match = 65535)
    upx_compress_config_t cconf; cconf.reset();
    cconf.conf_ucl.max_match = 65535;
    cconf.conf_lzma.max_num_probs = 1846 + (768 << 4); // ushort: ~28KB stack
    compressWithFilters(&ft, sa_cnt, &cconf);

    if (overlap)
    {
        opt->info_mode += !opt->info_mode ? 1 : 0;
        infoWarning("overlap - relocating load address (+%d bytes)", overlap);
        sa_cnt += overlap;
    }

/*
    if (bss_start && bss_end && !foundBss)
        infoWarning("%s: .bss section too small - use stack", fi->getName());
*/

    unsigned lzma_init = 0;

    if (M_IS_LZMA(ph.method))
    {
        sz_lunc = getLoaderSize();

        lzma_init = 0u - (sz_lunc - linker->getSymbolOffset("lzma.init"));
        defineDecompressorSymbols();
        linker->defineSymbol("entry", ih.epc);
        linker->defineSymbol("SC",
                             sa_cnt > (0x10000 << 2) ? sa_cnt >> 5 : sa_cnt >> 2);
        relocateLoader();

        buildPart2 = true;
        buildLoader(&ft);
    }

    memcpy(&oh, &ih, sizeof(ih));

    unsigned sz_cbh;
    putBkupHeader((const unsigned char *)&ih.epc, (unsigned char *)&bh, &sz_cbh);

    if (ih.is_ptr < (EXE_BS | (PS_RAM_SIZE - PS_STACK_SIZE)))
        oh.is_ptr = (EXE_BS | (PS_RAM_SIZE - 16));

    if (ih.da_ptr != 0 || ih.da_len != 0 ||
        ih.bs_ptr != 0 || ih.bs_len != 0)
        oh.da_ptr = oh.da_len =
        oh.bs_ptr = oh.bs_len = 0;

    const int lsize = getLoaderSize();

    unsigned filelen = ALIGN_UP(ih.tx_len, 4);

    const unsigned decomp_data_start = ih.tx_ptr;
    const unsigned comp_data_start = (decomp_data_start + filelen + overlap) - ph.c_len;

    const int h_len = lsize - getLoaderSectionStart("UPX1HEAD");
    int d_len = 0;
    int e_len = 0;

    if (isCon)
    {
        e_len = lsize - h_len;
        d_len = e_len - getLoaderSectionStart("con.entry");
    }
    else
    {
        const char* entry_lzma = !foundBss ? "cdb.entry.lzma" : "bss.cdb.entry.lzma";

        d_len = (lsize - h_len) - getLoaderSectionStart(M_IS_LZMA(ph.method) ? entry_lzma : "cdb.entry");
        e_len = (lsize - d_len) - h_len;
    }

    linker->defineSymbol("entry", ih.epc);
    linker->defineSymbol("SC", MIPS_LO(sa_cnt > (0x10000 << 2) ?
                                       sa_cnt >> 5 : sa_cnt >> 2));
    linker->defineSymbol("DECO", decomp_data_start);
    linker->defineSymbol("ldr_sz", M_IS_LZMA(ph.method) ? sz_lunc + 16 : (d_len-pad_code));

    if (foundBss)
    {
        if (M_IS_LZMA(ph.method))
            linker->defineSymbol("wrkmem", bss_end - 160 - getDecompressorWrkmemSize()
                                           - (sz_lunc + 16));
        else
            linker->defineSymbol("wrkmem", bss_end - 16 - (d_len - pad_code));
    }


    const unsigned entry = comp_data_start - e_len;
    oh.epc = oh.tx_ptr = entry;
    oh.tx_len = ph.c_len + e_len;

    unsigned pad = 0;

    if (!opt->ps1_exe.no_align || !isCon)
    {
        pad = oh.tx_len;
        oh.tx_len = ALIGN_UP(oh.tx_len, CD_SEC);
        pad = oh.tx_len - pad;
        oh.tx_ptr -= pad;
    }

    ibuf.clear(0,fdata_size);
    upx_bytep paddata = ibuf;

    if (M_IS_LZMA(ph.method))
    {
        linker->defineSymbol("lzma_init_off", lzma_init);
        linker->defineSymbol("gb_e", linker->getSymbolOffset("gb8_e"));
    }
    else
        if (isCon)
            linker->defineSymbol("gb_e", linker->getSymbolOffset(is32Bit ? "gb32_e" : "gb8_e"));

    if (isCon)
    {
        linker->defineSymbol("PAD", pad_code);
        if (M_IS_LZMA(ph.method))
            linker->defineSymbol("DCRT", (entry + getLoaderSectionStart("lzma.exec")));
        else
            linker->defineSymbol("DCRT", (entry + (e_len - d_len)));
    }
    else
    {
        linker->defineSymbol("PSVR", FIX_PSVR);
        linker->defineSymbol("CPDO", comp_data_start);
        if (M_IS_LZMA(ph.method))
        {
            unsigned entry_lzma = getLoaderSectionStart( !foundBss ? "cdb.entry.lzma" :
                                                                     "bss.cdb.entry.lzma");

            linker->defineSymbol("lzma_cpr", getLoaderSectionStart("lzma.exec") - entry_lzma);
        }
    }

    relocateLoader();
    //linker->dumpSymbols();
    MemBuffer loader(lsize);
    assert(lsize == getLoaderSize());
    memcpy(loader, getLoader(), lsize);
    patchPackHeader(loader, lsize);

    if (!isCon && M_IS_LZMA(ph.method) && (HD_CODE_OFS + d_len + h_len) > CD_SEC)
        throwInternalError("lzma --boot-only loader > 2048");

    // ps1_exe_t structure
    fo->write(&oh, sizeof(oh));
    fo->write(&bh, sz_cbh);
    // decompressor
    fo->write(loader + e_len, isCon ? h_len : (d_len + h_len));

    // header size is 2048 bytes + sector alignment
    fo->write(paddata, (pad + PS_HDR_SIZE) - fo->getBytesWritten());
    // entry
    fo->write(loader, e_len);
    // compressed body
    fo->write(obuf, ph.c_len);

    verifyOverlappingDecompression();
    if (!checkFinalCompressionRatio(fo))
        throwNotCompressible();

#if 0
    printf("%-13s: uncompressed  : %8ld bytes\n", getName(), (long) ph.u_len);
    printf("%-13s: compressed    : %8ld bytes\n", getName(), (long) ph.c_len);
    printf("%-13s: decompressor  : %8ld bytes\n", getName(), (long) lsize - h_len - pad_code);
    printf("%-13s: header comp   : %8ld bytes\n", getName(), (long) sz_cbh);
    printf("%-13s: overlap       : %8ld bytes\n", getName(), (long) overlap);
    printf("%-13s: load address  : %08X bytes\n", getName(), (unsigned int) oh.tx_ptr);
    printf("%-13s: code entry    : %08X bytes\n", getName(), (unsigned int) oh.epc);
    printf("%-13s: bbs start     : %08X bytes\n", getName(), (unsigned int) bss_start);
    printf("%-13s: bbs end       : %08X bytes\n", getName(), (unsigned int) bss_end);
    printf("%-13s: eof in mem IF : %08X bytes\n", getName(), (unsigned int) ih.tx_ptr + ih.tx_len);
    printf("%-13s: eof in mem OF : %08X bytes\n", getName(), (unsigned int) oh.tx_ptr + oh.tx_len);
    unsigned char i = 0;
    if (isCon) { if (foundBss) i = 1; }
    else { i = 2; if (M_IS_LZMA(ph.method)) { if (!foundBss) i = 3; else i = 4; } }
    const char *loader_method[] = { "con/stack", "con/bss", "cdb", "cdb/stack", "cdb/bss" };
    char method_name[32+1]; set_method_name(method_name, sizeof(method_name), ph.method, ph.level);
    printf("%-13s: methods       : %s, %s\n", getName(), method_name, loader_method[i]);
#endif
}


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

int PackPs1::canUnpack()
{
    if (!readFileHeader())
        return false;
    if (!readPackHeader(CD_SEC))
        return false;
    // check header as set by packer
    if (!readBkupHeader() || ph.c_len >= fdata_size)
        throwCantUnpack("header damaged");
    // generic check
    if (!checkFileHeader())
        throwCantUnpack("unsupported header flags");
    return true;
}


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

void PackPs1::unpack(OutputFile *fo)
{
    // restore orig exec hdr
    memcpy(&oh, &ih, sizeof(ih));
    memcpy(&oh.epc, &bh, SZ_IH_BKUP);

    // check for removed sector alignment
    assert(oh.tx_len >= ph.u_len);
    const unsigned pad = oh.tx_len - ph.u_len;

    ibuf.alloc(fdata_size > PS_HDR_SIZE ? fdata_size : PS_HDR_SIZE);
    obuf.allocForUncompression(ph.u_len, pad);

    fi->seek(PS_HDR_SIZE, SEEK_SET);
    fi->readx(ibuf, fdata_size);

    // decompress
    decompress(ibuf + (fdata_size - ph.c_len), obuf);

    // write decompressed file
    if (fo)
    {
        // write header
        fo->write(&oh, sizeof(oh));
        // align the ps exe header (mode 2 sector data size)
        ibuf.clear();
        fo->write(ibuf, PS_HDR_SIZE - fo->getBytesWritten());
        // write uncompressed data + pad
        obuf.clear(ph.u_len, pad);
        fo->write(obuf, ph.u_len + pad);
    }
}


/*
vi:ts=4:et:nowrap
*/