ruberon/source/ELF.ob07

MODULE ELF;

IMPORT
    BIN,
    WR := WRITER,
    CHL := CHUNKLISTS,
    LISTS,
    PE32,
    UTILS IN "./utils/UTILS.ob07",
    STRINGS IN "./strings/STRINGS.ob07";


CONST

    EI_NIDENT = 16;
    ET_EXEC = 2;
    ET_DYN = 3;

    EM_386 = 3;
    EM_8664 = 3EH;

    ELFCLASS32 = 1;
    ELFCLASS64 = 2;

    ELFDATA2LSB = 1;
    ELFDATA2MSB = 2;

    PF_X = 1;
    PF_W = 2;
    PF_R = 4;


TYPE

    Elf32_Ehdr = RECORD

        e_ident: ARRAY EI_NIDENT OF BYTE;

        e_type,
        e_machine: WCHAR;

        e_version,
        e_entry,
        e_phoff,
        e_shoff,
        e_flags: INTEGER;

        e_ehsize,
        e_phentsize,
        e_phnum,
        e_shentsize,
        e_shnum,
        e_shstrndx: WCHAR

    END;


    Elf32_Phdr = RECORD

        p_type,
        p_offset,
        p_vaddr,
        p_paddr,
        p_filesz,
        p_memsz,
        p_flags,
        p_align: INTEGER

    END;


    Elf32_Dyn = POINTER TO RECORD (LISTS.ITEM)

        d_tag, d_val: INTEGER

    END;


    Elf32_Sym = POINTER TO RECORD (LISTS.ITEM)

        name, value, size: INTEGER;
        info, other: CHAR;
        shndx: WCHAR

    END;


VAR

    dynamic: LISTS.LIST;
    strtab:  CHL.BYTELIST;
    symtab:  LISTS.LIST;

    hashtab, bucket, chain: CHL.INTLIST;


PROCEDURE Write16 (w: WCHAR);
    BEGIN
        WR.Write16LE(ORD(w))
    END Write16;


PROCEDURE WritePH (ph: Elf32_Phdr);
    BEGIN
        WR.Write32LE(ph.p_type);
        WR.Write32LE(ph.p_offset);
        WR.Write32LE(ph.p_vaddr);
        WR.Write32LE(ph.p_paddr);
        WR.Write32LE(ph.p_filesz);
        WR.Write32LE(ph.p_memsz);
        WR.Write32LE(ph.p_flags);
        WR.Write32LE(ph.p_align)
    END WritePH;


PROCEDURE WritePH64 (ph: Elf32_Phdr);
    BEGIN
        WR.Write32LE(ph.p_type);
        WR.Write32LE(ph.p_flags);
        WR.Write64LE(ph.p_offset);
        WR.Write64LE(ph.p_vaddr);
        WR.Write64LE(ph.p_paddr);
        WR.Write64LE(ph.p_filesz);
        WR.Write64LE(ph.p_memsz);
        WR.Write64LE(ph.p_align)
    END WritePH64;


PROCEDURE NewDyn (tag, val: INTEGER);
    VAR
        dyn: Elf32_Dyn;

    BEGIN
        NEW(dyn);
        dyn.d_tag := tag;
        dyn.d_val := val;
        LISTS.push(dynamic, dyn)
    END NewDyn;


PROCEDURE NewSym (name, value, size: INTEGER; info, other: CHAR; shndx: WCHAR);
    VAR
        sym: Elf32_Sym;

    BEGIN
        NEW(sym);
        sym.name := name;
        sym.value := value;
        sym.size := size;
        sym.info := info;
        sym.other := other;
        sym.shndx := shndx;

        LISTS.push(symtab, sym)
    END NewSym;


PROCEDURE MakeHash (bucket, chain: CHL.INTLIST; symCount: INTEGER);
    VAR
        symi, hi, k: INTEGER;

    BEGIN
        FOR symi := 0 TO symCount - 1 DO
            CHL.SetInt(chain, symi, 0);
            hi := CHL.GetInt(hashtab, symi) MOD symCount;
            IF CHL.GetInt(bucket, hi) # 0 THEN
                k := symi;
                WHILE CHL.GetInt(chain, k) # 0 DO
                    k := CHL.GetInt(chain, k)
                END;
                CHL.SetInt(chain, k, CHL.GetInt(bucket, hi))
            END;
            CHL.SetInt(bucket, hi, symi)
        END
    END MakeHash;


PROCEDURE write* (program: BIN.PROGRAM; FileName: ARRAY OF CHAR; fini: INTEGER; so, amd64: BOOLEAN);
    CONST
        interp  =  0;
        dyn     =  1;
        header  =  2;
        text    =  3;
        data    =  4;
        bss     =  5;

        linuxInterpreter64 = "/lib64/ld-linux-x86-64.so.2";
        linuxInterpreter32 = "/lib/ld-linux.so.2";

        exeBaseAddress32 = 8048000H;
        exeBaseAddress64 = 400000H;
        dllBaseAddress = 0;

        DT_NULL = 0;
        DT_NEEDED = 1;
        DT_HASH = 4;
        DT_STRTAB = 5;
        DT_SYMTAB = 6;
        DT_RELA = 7;
        DT_RELASZ = 8;
        DT_RELAENT = 9;
        DT_STRSZ = 10;
        DT_SYMENT = 11;
        DT_INIT = 12;
        DT_FINI = 13;
        DT_SONAME = 14;
        DT_REL = 17;
        DT_RELSZ = 18;
        DT_RELENT = 19;

    VAR
        ehdr: Elf32_Ehdr;
        phdr: ARRAY 16 OF Elf32_Phdr;

        i, BaseAdr, DynAdr, offset, pad, VA, symCount: INTEGER;

        SizeOf: RECORD header, code, data, bss: INTEGER END;

        Offset: RECORD symtab, reltab, hash, strtab: INTEGER END;

        Interpreter: ARRAY 40 OF CHAR; lenInterpreter: INTEGER;

        item: LISTS.ITEM;

        Name: ARRAY 2048 OF CHAR;

        Address: PE32.VIRTUAL_ADDR;

    BEGIN
        dynamic := LISTS.create(NIL);
        symtab  := LISTS.create(NIL);
        strtab  := CHL.CreateByteList();

        IF amd64 THEN
            BaseAdr := exeBaseAddress64;
            Interpreter := linuxInterpreter64
        ELSE
            BaseAdr := exeBaseAddress32;
            Interpreter := linuxInterpreter32
        END;

        IF so THEN
            BaseAdr := dllBaseAddress
        END;

        lenInterpreter := LENGTH(Interpreter) + 1;

        SizeOf.code := CHL.Length(program.code);
        SizeOf.data := CHL.Length(program.data);
        SizeOf.bss  := program.bss;

        ehdr.e_ident[0] := 7FH;
        ehdr.e_ident[1] := ORD("E");
        ehdr.e_ident[2] := ORD("L");
        ehdr.e_ident[3] := ORD("F");
        IF amd64 THEN
            ehdr.e_ident[4] := ELFCLASS64
        ELSE
            ehdr.e_ident[4] := ELFCLASS32
        END;
        ehdr.e_ident[5] := ELFDATA2LSB;
        ehdr.e_ident[6] := 1;
        ehdr.e_ident[7] := 3;
        FOR i := 8 TO EI_NIDENT - 1 DO
            ehdr.e_ident[i] := 0
        END;

        IF so THEN
            ehdr.e_type := WCHR(ET_DYN)
        ELSE
            ehdr.e_type := WCHR(ET_EXEC)
        END;

        ehdr.e_version := 1;
        ehdr.e_shoff := 0;
        ehdr.e_flags := 0;
        ehdr.e_shnum := WCHR(0);
        ehdr.e_shstrndx := WCHR(0);
        ehdr.e_phnum := WCHR(6);

        IF amd64 THEN
            ehdr.e_machine := WCHR(EM_8664);
            ehdr.e_phoff := 40H;
            ehdr.e_ehsize := WCHR(40H);
            ehdr.e_phentsize := WCHR(38H);
            ehdr.e_shentsize := WCHR(40H)
        ELSE
            ehdr.e_machine := WCHR(EM_386);
            ehdr.e_phoff := 34H;
            ehdr.e_ehsize := WCHR(34H);
            ehdr.e_phentsize := WCHR(20H);
            ehdr.e_shentsize := WCHR(28H)
        END;

        SizeOf.header := ORD(ehdr.e_ehsize) + ORD(ehdr.e_phentsize) * ORD(ehdr.e_phnum);

        phdr[interp].p_type := 3;
        phdr[interp].p_offset := SizeOf.header;
        phdr[interp].p_vaddr := BaseAdr + phdr[interp].p_offset;
        phdr[interp].p_paddr := phdr[interp].p_vaddr;
        phdr[interp].p_filesz := lenInterpreter;
        phdr[interp].p_memsz := lenInterpreter;
        phdr[interp].p_flags := PF_R;
        phdr[interp].p_align := 1;

        phdr[dyn].p_type := 2;
        phdr[dyn].p_offset := phdr[interp].p_offset + phdr[interp].p_filesz;
        phdr[dyn].p_vaddr := BaseAdr + phdr[dyn].p_offset;
        phdr[dyn].p_paddr := phdr[dyn].p_vaddr;

        hashtab := CHL.CreateIntList();

        CHL.PushInt(hashtab, STRINGS.HashStr(""));
        NewSym(CHL.PushStr(strtab, ""), 0, 0, 0X, 0X, 0X);
        CHL.PushInt(hashtab, STRINGS.HashStr("dlopen"));
        NewSym(CHL.PushStr(strtab, "dlopen"), 0, 0, 12X, 0X, 0X);
        CHL.PushInt(hashtab, STRINGS.HashStr("dlsym"));
        NewSym(CHL.PushStr(strtab, "dlsym"), 0, 0, 12X, 0X, 0X);

        IF so THEN
            item := program.exp_list.first;
            WHILE item # NIL DO
                ASSERT(CHL.GetStr(program.export, item(BIN.EXPRT).nameoffs, Name));
                CHL.PushInt(hashtab, STRINGS.HashStr(Name));
                NewSym(CHL.PushStr(strtab, Name), item(BIN.EXPRT).label, 0, 12X, 0X, 0X);
                item := item.next
            END;
            ASSERT(CHL.GetStr(program.data, program.modname, Name))
        END;

        symCount := LISTS.count(symtab);

        bucket := CHL.CreateIntList();
        chain  := CHL.CreateIntList();

        FOR i := 1 TO symCount DO
            CHL.PushInt(bucket, 0);
            CHL.PushInt(chain, 0)
        END;

        MakeHash(bucket, chain, symCount);

        NewDyn(DT_NEEDED, CHL.PushStr(strtab, "libdl.so.2"));
        NewDyn(DT_STRTAB, 0);
        NewDyn(DT_STRSZ, CHL.Length(strtab));
        NewDyn(DT_SYMTAB, 0);

        IF amd64 THEN
            NewDyn(DT_SYMENT, 24);
            NewDyn(DT_RELA, 0);
            NewDyn(DT_RELASZ, 48);
            NewDyn(DT_RELAENT, 24)
        ELSE
            NewDyn(DT_SYMENT, 16);
            NewDyn(DT_REL, 0);
            NewDyn(DT_RELSZ, 16);
            NewDyn(DT_RELENT, 8)
        END;

        NewDyn(DT_HASH, 0);

        IF so THEN
            NewDyn(DT_SONAME, CHL.PushStr(strtab, Name));
            NewDyn(DT_INIT, 0);
            NewDyn(DT_FINI, 0)
        END;

        NewDyn(DT_NULL, 0);

        Offset.symtab := LISTS.count(dynamic) * (8 + 8 * ORD(amd64));
        Offset.reltab := Offset.symtab + symCount * (16 + 8 * ORD(amd64));
        Offset.hash   := Offset.reltab + (8 + 16 * ORD(amd64)) * 2;
        Offset.strtab := Offset.hash + (symCount * 2 + 2) * 4;

        DynAdr := phdr[dyn].p_offset + BaseAdr;

        item := LISTS.getidx(dynamic, 1); item(Elf32_Dyn).d_val := Offset.strtab + DynAdr;
        item := LISTS.getidx(dynamic, 3); item(Elf32_Dyn).d_val := Offset.symtab + DynAdr;
        item := LISTS.getidx(dynamic, 5); item(Elf32_Dyn).d_val := Offset.reltab + DynAdr;
        item := LISTS.getidx(dynamic, 8); item(Elf32_Dyn).d_val := Offset.hash   + DynAdr;

        phdr[dyn].p_filesz := Offset.strtab + CHL.Length(strtab) + 8 + 8 * ORD(amd64);
        phdr[dyn].p_memsz  := phdr[dyn].p_filesz;

        phdr[dyn].p_flags := PF_R;
        phdr[dyn].p_align := 1;

        offset := 0;

        phdr[header].p_type := 1;
        phdr[header].p_offset := offset;
        phdr[header].p_vaddr := BaseAdr;
        phdr[header].p_paddr := BaseAdr;
        phdr[header].p_filesz := SizeOf.header + lenInterpreter + phdr[dyn].p_filesz;
        phdr[header].p_memsz  := phdr[header].p_filesz;
        phdr[header].p_flags := PF_R + PF_W;
        phdr[header].p_align := 1000H;

        INC(offset, phdr[header].p_filesz);
        VA := BaseAdr + offset + 1000H;

        phdr[text].p_type := 1;
        phdr[text].p_offset := offset;
        phdr[text].p_vaddr := VA;
        phdr[text].p_paddr := VA;
        phdr[text].p_filesz := SizeOf.code;
        phdr[text].p_memsz := SizeOf.code;
        phdr[text].p_flags := PF_X + PF_R;
        phdr[text].p_align := 1000H;

        ehdr.e_entry := phdr[text].p_vaddr;

        INC(offset, phdr[text].p_filesz);
        VA := BaseAdr + offset + 2000H;
        pad := (16 - VA MOD 16) MOD 16;

        phdr[data].p_type := 1;
        phdr[data].p_offset := offset;
        phdr[data].p_vaddr := VA;
        phdr[data].p_paddr := VA;
        phdr[data].p_filesz := SizeOf.data + pad;
        phdr[data].p_memsz := SizeOf.data + pad;
        phdr[data].p_flags := PF_R + PF_W;
        phdr[data].p_align := 1000H;

        INC(offset, phdr[data].p_filesz);
        VA := BaseAdr + offset + 3000H;

        phdr[bss].p_type := 1;
        phdr[bss].p_offset := offset;
        phdr[bss].p_vaddr := VA;
        phdr[bss].p_paddr := VA;
        phdr[bss].p_filesz := 0;
        phdr[bss].p_memsz := SizeOf.bss + 16;
        phdr[bss].p_flags := PF_R + PF_W;
        phdr[bss].p_align := 1000H;

        Address.Code   := ehdr.e_entry;
        Address.Data   := phdr[data].p_vaddr + pad;
        Address.Bss    := WR.align(phdr[bss].p_vaddr, 16);
        Address.Import := 0;

        PE32.fixup(program, Address, amd64);

        item := symtab.first;
        WHILE item # NIL DO
            IF item(Elf32_Sym).value # 0 THEN
                INC(item(Elf32_Sym).value, ehdr.e_entry)
            END;
            item := item.next
        END;

        IF so THEN
            item := LISTS.getidx(dynamic, 10); item(Elf32_Dyn).d_val := ehdr.e_entry;
            item := LISTS.getidx(dynamic, 11); item(Elf32_Dyn).d_val := BIN.GetLabel(program, fini) + ehdr.e_entry
        END;

        WR.Create(FileName);

        FOR i := 0 TO EI_NIDENT - 1 DO
            WR.WriteByte(ehdr.e_ident[i])
        END;

        Write16(ehdr.e_type);
        Write16(ehdr.e_machine);

        WR.Write32LE(ehdr.e_version);
        IF amd64 THEN
            WR.Write64LE(ehdr.e_entry);
            WR.Write64LE(ehdr.e_phoff);
            WR.Write64LE(ehdr.e_shoff)
        ELSE
            WR.Write32LE(ehdr.e_entry);
            WR.Write32LE(ehdr.e_phoff);
            WR.Write32LE(ehdr.e_shoff)
        END;
        WR.Write32LE(ehdr.e_flags);

        Write16(ehdr.e_ehsize);
        Write16(ehdr.e_phentsize);
        Write16(ehdr.e_phnum);
        Write16(ehdr.e_shentsize);
        Write16(ehdr.e_shnum);
        Write16(ehdr.e_shstrndx);

        IF amd64 THEN
            WritePH64(phdr[interp]);
            WritePH64(phdr[dyn]);
            WritePH64(phdr[header]);
            WritePH64(phdr[text]);
            WritePH64(phdr[data]);
            WritePH64(phdr[bss])
        ELSE
            WritePH(phdr[interp]);
            WritePH(phdr[dyn]);
            WritePH(phdr[header]);
            WritePH(phdr[text]);
            WritePH(phdr[data]);
            WritePH(phdr[bss])
        END;

        FOR i := 0 TO lenInterpreter - 1 DO
            WR.WriteByte(ORD(Interpreter[i]))
        END;

        IF amd64 THEN
            item := dynamic.first;
            WHILE item # NIL DO
                WR.Write64LE(item(Elf32_Dyn).d_tag);
                WR.Write64LE(item(Elf32_Dyn).d_val);
                item := item.next
            END;

            item := symtab.first;
            WHILE item # NIL DO
                WR.Write32LE(item(Elf32_Sym).name);
                WR.WriteByte(ORD(item(Elf32_Sym).info));
                WR.WriteByte(ORD(item(Elf32_Sym).other));
                Write16(item(Elf32_Sym).shndx);
                WR.Write64LE(item(Elf32_Sym).value);
                WR.Write64LE(item(Elf32_Sym).size);
                item := item.next
            END;

            WR.Write64LE(phdr[dyn].p_filesz + DynAdr - 16);
            WR.Write32LE(1);
            WR.Write32LE(1);
            WR.Write64LE(0);
            WR.Write64LE(phdr[dyn].p_filesz + DynAdr - 8);
            WR.Write32LE(1);
            WR.Write32LE(2);
            WR.Write64LE(0)

        ELSE
            item := dynamic.first;
            WHILE item # NIL DO
                WR.Write32LE(item(Elf32_Dyn).d_tag);
                WR.Write32LE(item(Elf32_Dyn).d_val);
                item := item.next
            END;

            item := symtab.first;
            WHILE item # NIL DO
                WR.Write32LE(item(Elf32_Sym).name);
                WR.Write32LE(item(Elf32_Sym).value);
                WR.Write32LE(item(Elf32_Sym).size);
                WR.WriteByte(ORD(item(Elf32_Sym).info));
                WR.WriteByte(ORD(item(Elf32_Sym).other));
                Write16(item(Elf32_Sym).shndx);
                item := item.next
            END;

            WR.Write32LE(phdr[dyn].p_filesz + DynAdr - 8);
            WR.Write32LE(00000101H);
            WR.Write32LE(phdr[dyn].p_filesz + DynAdr - 4);
            WR.Write32LE(00000201H)

        END;

        WR.Write32LE(symCount);
        WR.Write32LE(symCount);

        FOR i := 0 TO symCount - 1 DO
            WR.Write32LE(CHL.GetInt(bucket, i))
        END;

        FOR i := 0 TO symCount - 1 DO
            WR.Write32LE(CHL.GetInt(chain, i))
        END;

        CHL.WriteToFile(strtab);

        IF amd64 THEN
            WR.Write64LE(0);
            WR.Write64LE(0)
        ELSE
            WR.Write32LE(0);
            WR.Write32LE(0)
        END;

        CHL.WriteToFile(program.code);
        WHILE pad > 0 DO
            WR.WriteByte(0);
            DEC(pad)
        END;
        CHL.WriteToFile(program.data);
        WR.Close;
        UTILS.chmod(FileName)
    END write;


END ELF.