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162 | import pako from "pako";
import { te, concat } from "./util";
export interface SnapshotFile {
/** path inside the archive, without the top-level prefix */
path: string;
mode: number; // 0o644 / 0o755
symlink: boolean;
data: Uint8Array;
}
function safePath(p: string): boolean {
if (!p || p.startsWith("/") || p.includes("\\")) return false;
return p.split("/").every((c) => c !== "" && c !== "." && c !== "..");
}
function safeTarget(t: string): boolean {
if (t.startsWith("/")) return false;
return t.split("/").every((c) => c !== "..");
}
function safeEntry(f: SnapshotFile): boolean {
if (!safePath(f.path)) return false;
if (f.symlink && !safeTarget(new TextDecoder().decode(f.data))) return false;
return true;
}
function octal(n: number, width: number): Uint8Array {
const s = n.toString(8).padStart(width - 1, "0") + "\0";
return te.encode(s);
}
function tarHeader(path: string, mode: number, size: number, mtime: number, typeflag: string, linkname: string): Uint8Array {
const h = new Uint8Array(512);
let name = path;
let prefix = "";
if (te.encode(name).length > 100) {
// ustar prefix split at a slash
const idx = path.slice(0, 155).lastIndexOf("/");
if (idx > 0) {
prefix = path.slice(0, idx);
name = path.slice(idx + 1);
}
}
h.set(te.encode(name).subarray(0, 100), 0);
h.set(octal(mode, 8), 100);
h.set(octal(0, 8), 108); // uid
h.set(octal(0, 8), 116); // gid
h.set(octal(size, 12), 124);
h.set(octal(mtime, 12), 136);
h.set(te.encode(" "), 148); // checksum placeholder = spaces
h.set(te.encode(typeflag), 156);
h.set(te.encode(linkname).subarray(0, 100), 157);
h.set(te.encode("ustar\0" + "00"), 257);
h.set(te.encode("root").subarray(0, 32), 265);
h.set(te.encode("root").subarray(0, 32), 297);
h.set(te.encode(prefix).subarray(0, 155), 345);
let sum = 0;
for (let i = 0; i < 512; i++) sum += h[i];
h.set(te.encode(sum.toString(8).padStart(6, "0") + "\0 "), 148);
return h;
}
export function tarGz(prefix: string, files: SnapshotFile[], mtime: number): Uint8Array {
const parts: Uint8Array[] = [];
for (const f of files) {
if (!safeEntry(f)) continue;
const path = `${prefix}/${f.path}`;
if (f.symlink) {
const target = new TextDecoder().decode(f.data);
parts.push(tarHeader(path, 0o777, 0, mtime, "2", target));
continue;
}
parts.push(tarHeader(path, f.mode, f.data.length, mtime, "0", ""));
parts.push(f.data);
const pad = (512 - (f.data.length % 512)) % 512;
if (pad) parts.push(new Uint8Array(pad));
}
parts.push(new Uint8Array(1024)); // end-of-archive
return pako.gzip(concat(parts));
}
const CRC_TABLE = (() => {
const t = new Uint32Array(256);
for (let n = 0; n < 256; n++) {
let c = n;
for (let k = 0; k < 8; k++) c = c & 1 ? 0xedb88320 ^ (c >>> 1) : c >>> 1;
t[n] = c >>> 0;
}
return t;
})();
function crc32(data: Uint8Array): number {
let c = 0xffffffff;
for (let i = 0; i < data.length; i++) c = CRC_TABLE[(c ^ data[i]) & 0xff] ^ (c >>> 8);
return (c ^ 0xffffffff) >>> 0;
}
function dosDateTime(unixSecs: number): { time: number; date: number } {
const d = new Date(unixSecs * 1000);
const date = (((d.getUTCFullYear() - 1980) & 0x7f) << 9) | ((d.getUTCMonth() + 1) << 5) | d.getUTCDate();
const time = (d.getUTCHours() << 11) | (d.getUTCMinutes() << 5) | (d.getUTCSeconds() >> 1);
return { time, date };
}
export function zip(prefix: string, files: SnapshotFile[], mtime: number): Uint8Array {
const { time, date } = dosDateTime(mtime);
const parts: Uint8Array[] = [];
const central: Uint8Array[] = [];
let offset = 0;
for (const f of files) {
if (!safeEntry(f)) continue;
const name = te.encode(`${prefix}/${f.path}`);
const crc = crc32(f.data);
const compressed = f.data.length ? pako.deflateRaw(f.data) : new Uint8Array(0);
const method = f.data.length ? 8 : 0;
const local = new Uint8Array(30 + name.length);
const lv = new DataView(local.buffer);
lv.setUint32(0, 0x04034b50, true);
lv.setUint16(4, 20, true);
lv.setUint16(8, method, true);
lv.setUint16(10, time, true);
lv.setUint16(12, date, true);
lv.setUint32(14, crc, true);
lv.setUint32(18, compressed.length, true);
lv.setUint32(22, f.data.length, true);
lv.setUint16(26, name.length, true);
local.set(name, 30);
parts.push(local, compressed);
const cd = new Uint8Array(46 + name.length);
const cv = new DataView(cd.buffer);
cv.setUint32(0, 0x02014b50, true);
cv.setUint16(4, (3 << 8) | 20, true); // made by unix
cv.setUint16(6, 20, true);
cv.setUint16(10, method, true);
cv.setUint16(12, time, true);
cv.setUint16(14, date, true);
cv.setUint32(16, crc, true);
cv.setUint32(20, compressed.length, true);
cv.setUint32(24, f.data.length, true);
cv.setUint16(28, name.length, true);
cv.setUint32(38, ((f.symlink ? 0o120000 | 0o777 : 0o100000 | f.mode) << 16) >>> 0, true);
cv.setUint32(42, offset, true);
cd.set(name, 46);
central.push(cd);
offset += local.length + compressed.length;
}
const cdStart = offset;
let cdLen = 0;
for (const c of central) cdLen += c.length;
const eocd = new Uint8Array(22);
const ev = new DataView(eocd.buffer);
ev.setUint32(0, 0x06054b50, true);
ev.setUint16(8, central.length, true);
ev.setUint16(10, central.length, true);
ev.setUint32(12, cdLen, true);
ev.setUint32(16, cdStart, true);
return concat([...parts, ...central, eocd]);
}
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