aboutsummaryrefslogtreecommitdiff
path: root/src/lundump.js
blob: 5ea459e151227109af97f33d3318ac9c6dbec58f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
/*jshint esversion: 6 */
"use strict";

const assert  = require('assert');

const defs     = require('./defs.js');
const ldo      = require('./ldo.js');
const lfunc    = require('./lfunc.js');
const lobject  = require('./lobject.js');
const lopcodes = require('./lopcodes.js');
const lstring  = require('./lstring.js');
const llex     = require('./llex.js');

let LUAC_DATA = [0x19, 0x93, defs.char["\r"], defs.char["\n"], 0x1a, defs.char["\n"]];

class BytecodeParser {

    constructor(L, buffer, name) {
        this.intSize = 4;
        this.size_tSize = 8;
        this.instructionSize = 4;
        this.integerSize = 4;
        this.numberSize = 8;

        assert(buffer instanceof llex.MBuffer, "BytecodeParser only operates on a MBuffer");
        assert(Array.isArray(name));

        if (name[0] == defs.char["@"] || name[0] == defs.char["="])
            this.name = name.slice(1);
        else if (name[0] == defs.LUA_SIGNATURE.charCodeAt(0))
            this.name = defs.to_luastring("binary string", true);
        else
            this.name = name;

        this.L = L;
        this.buffer = buffer;

        // Used to do buffer to number conversions
        this.dv = new DataView(
            new ArrayBuffer(
                Math.max(this.intSize, this.size_tSize, this.instructionSize, this.integerSize, this.numberSize)
            )
        );
    }

    read(size) {
        let buffer = this.buffer.read(size);
        assert(Array.isArray(buffer));
        if (buffer.length < size) this.error("truncated");
        return buffer;
    }

    readByte() {
        return this.read(1)[0];
    }

    readInteger() {
        let buffer = this.read(this.integerSize);
        for (let i = 0; i < buffer.length; i++)
            this.dv.setUint8(i, buffer[i]);

        return this.dv.getInt32(0, true);
    }

    readSize_t() {
        return this.readInteger();
    }

    readInt() {
        let buffer = this.read(this.intSize);

        for (let i = 0; i < buffer.length; i++)
            this.dv.setUint8(i, buffer[i]);

        return this.dv.getInt32(0, true);
    }

    readNumber() {
        let buffer = this.read(this.numberSize);

        for (let i = 0; i < buffer.length; i++)
            this.dv.setUint8(i, buffer[i]);

        return this.dv.getFloat64(0, true);
    }

    readString() {
        let size = Math.max(this.readByte() - 1, 0);

        if (size + 1 === 0xFF)
            size = this.readSize_t() - 1;

        if (size === 0) {
            return null;
        }

        return lstring.luaS_new(this.L, this.read(size));
    }

    /* creates a mask with 'n' 1 bits at position 'p' */
    static MASK1(n, p) {
        return ((~((~0)<<(n)))<<(p));
    }

    /* creates a mask with 'n' 0 bits at position 'p' */
    static MASK0(n, p) {
        return (~BytecodeParser.MASK1(n,p));
    }

    readInstruction() {
        let ins = new DataView(new ArrayBuffer(this.instructionSize));
        for (let i = 0; i < this.instructionSize; i++)
            ins.setUint8(i, this.readByte());

        return ins.getUint32(0, true);
    }

    readCode(f) {
        let n = this.readInt();
        let o = lopcodes;
        let p = BytecodeParser;

        for (let i = 0; i < n; i++) {
            let ins = this.readInstruction();
            f.code[i] = {
                code:   ins,
                opcode: (ins >> o.POS_OP) & p.MASK1(o.SIZE_OP, 0),
                A:      (ins >> o.POS_A)  & p.MASK1(o.SIZE_A,  0),
                B:      (ins >> o.POS_B)  & p.MASK1(o.SIZE_B,  0),
                C:      (ins >> o.POS_C)  & p.MASK1(o.SIZE_C,  0),
                Bx:     (ins >> o.POS_Bx) & p.MASK1(o.SIZE_Bx, 0),
                Ax:     (ins >> o.POS_Ax) & p.MASK1(o.SIZE_Ax, 0),
                sBx:    ((ins >> o.POS_Bx) & p.MASK1(o.SIZE_Bx, 0)) - o.MAXARG_sBx
            };
        }
    }

    readUpvalues(f) {
        let n = this.readInt();

        for (let i = 0; i < n; i++) {
            f.upvalues[i] = {
                name:    null,
                instack: this.readByte(),
                idx:     this.readByte()
            };
        }
    }

    readConstants(f) {
        let n = this.readInt();

        for (let i = 0; i < n; i++) {
            let t = this.readByte();

            switch (t) {
            case defs.CT.LUA_TNIL:
                f.k.push(new lobject.TValue(defs.CT.LUA_TNIL, null));
                break;
            case defs.CT.LUA_TBOOLEAN:
                f.k.push(new lobject.TValue(defs.CT.LUA_TBOOLEAN, this.readByte()));
                break;
            case defs.CT.LUA_TNUMFLT:
                f.k.push(new lobject.TValue(defs.CT.LUA_TNUMFLT, this.readNumber()));
                break;
            case defs.CT.LUA_TNUMINT:
                f.k.push(new lobject.TValue(defs.CT.LUA_TNUMINT, this.readInteger()));
                break;
            case defs.CT.LUA_TSHRSTR:
            case defs.CT.LUA_TLNGSTR:
                f.k.push(new lobject.TValue(defs.CT.LUA_TLNGSTR, this.readString()));
                break;
            default:
                this.error(`unrecognized constant '${t}'`);
            }
        }
    }

    readProtos(f) {
        let n = this.readInt();

        for (let i = 0; i < n; i++) {
            f.p[i] = new lfunc.Proto(this.L);
            this.readFunction(f.p[i], f.source);
        }
    }

    readDebug(f) {
        let n = this.readInt();
        for (let i = 0; i < n; i++)
            f.lineinfo[i] = this.readInt();

        n = this.readInt();
        for (let i = 0; i < n; i++) {
            f.locvars[i] = {
                varname: this.readString(),
                startpc: this.readInt(),
                endpc:   this.readInt()
            };
        }

        n = this.readInt();
        for (let i = 0; i < n; i++) {
            f.upvalues[i].name = this.readString();
        }
    }

    readFunction(f, psource) {
        f.source = this.readString();
        if (f.source === null)  /* no source in dump? */
            f.source = psource;  /* reuse parent's source */
        f.linedefined = this.readInt();
        f.lastlinedefined = this.readInt();
        f.numparams = this.readByte();
        f.is_vararg = this.readByte();
        f.maxstacksize = this.readByte();
        this.readCode(f);
        this.readConstants(f);
        this.readUpvalues(f);
        this.readProtos(f);
        this.readDebug(f);
    }

    checkliteral(s, msg) {
        let buff = this.read(s.length);
        if (buff.join() !== s.join())
            this.error(msg);
    }

    checkHeader() {
        this.checkliteral(defs.to_luastring(defs.LUA_SIGNATURE.substring(1)), "not a"); /* 1st char already checked */

        if (this.readByte() !== 0x53)
            this.error("version mismatch in");

        if (this.readByte() !== 0)
            this.error("format mismatch in");

        this.checkliteral(LUAC_DATA, "corrupted");

        this.intSize         = this.readByte();
        this.size_tSize      = this.readByte();
        this.instructionSize = this.readByte();
        this.integerSize     = this.readByte();
        this.numberSize      = this.readByte();

        this.checksize(this.intSize, 4, "int");
        this.checksize(this.size_tSize, 8, "size_t");
        this.checksize(this.instructionSize, 4, "instruction");
        this.checksize(this.integerSize, 4, "integer");
        this.checksize(this.numberSize, 8, "number");

        if (this.readInteger() !== 0x5678)
            this.error("endianness mismatch in");

        if (this.readNumber() !== 370.5)
            this.error("float format mismatch in");

    }

    error(why) {
        lobject.luaO_pushfstring(this.L, defs.to_luastring("%s: %s precompiled chunk"), this.name, defs.to_luastring(why));
        ldo.luaD_throw(this.L, defs.thread_status.LUA_ERRSYNTAX);
    }

    checksize(byte, size, tname) {
        if (byte !== size)
            this.error(`${tname} size mismatch in`);
    }
}

const luaU_undump = function(L, buffer, name) {
    let S = new BytecodeParser(L, buffer, name);
    S.checkHeader();
    let cl = lfunc.luaF_newLclosure(L, S.readByte());
    L.stack[L.top++] = new lobject.TValue(defs.CT.LUA_TLCL, cl);
    cl.p = new lfunc.Proto(L);
    S.readFunction(cl.p, null);
    assert(cl.nupvalues === cl.p.upvalues.length);
    /* luai_verifycode */
    return cl;
};

module.exports.luaU_undump = luaU_undump;