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go/misc/wasm/wasm_exec.js
Richard Musiol ecba83520d syscall: on wasm, do not panic if "process" global is not defined
When running wasm in the browser, the "process" global is not defined.
This causes functions like os.Getpid() to panic, which is unusual.
For example on Windows os.Getpid() returns -1 and does not panic.

This change adds a dummy polyfill for "process" which returns -1 or an
error. It also extends the polyfill for "fs".

Fixes #34627
Replaces CL 199357

Change-Id: Ifeb12fe7e152c517848933a9ab5f6f749896dcef
Reviewed-on: https://go-review.googlesource.com/c/go/+/199698
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-10-08 02:42:57 +00:00

571 lines
16 KiB
JavaScript

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
(() => {
// Map multiple JavaScript environments to a single common API,
// preferring web standards over Node.js API.
//
// Environments considered:
// - Browsers
// - Node.js
// - Electron
// - Parcel
if (typeof global !== "undefined") {
// global already exists
} else if (typeof window !== "undefined") {
window.global = window;
} else if (typeof self !== "undefined") {
self.global = self;
} else {
throw new Error("cannot export Go (neither global, window nor self is defined)");
}
if (!global.require && typeof require !== "undefined") {
global.require = require;
}
if (!global.fs && global.require) {
global.fs = require("fs");
}
const enosys = () => {
const err = new Error("not implemented");
err.code = "ENOSYS";
return err;
};
if (!global.fs) {
let outputBuf = "";
global.fs = {
constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused
writeSync(fd, buf) {
outputBuf += decoder.decode(buf);
const nl = outputBuf.lastIndexOf("\n");
if (nl != -1) {
console.log(outputBuf.substr(0, nl));
outputBuf = outputBuf.substr(nl + 1);
}
return buf.length;
},
write(fd, buf, offset, length, position, callback) {
if (offset !== 0 || length !== buf.length || position !== null) {
callback(enosys());
return;
}
const n = this.writeSync(fd, buf);
callback(null, n);
},
chmod(path, mode, callback) { callback(enosys()); },
chown(path, uid, gid, callback) { callback(enosys()); },
close(fd, callback) { callback(enosys()); },
fchmod(fd, mode, callback) { callback(enosys()); },
fchown(fd, uid, gid, callback) { callback(enosys()); },
fstat(fd, callback) { callback(enosys()); },
fsync(fd, callback) { callback(null); },
ftruncate(fd, length, callback) { callback(enosys()); },
lchown(path, uid, gid, callback) { callback(enosys()); },
link(path, link, callback) { callback(enosys()); },
lstat(path, callback) { callback(enosys()); },
mkdir(path, perm, callback) { callback(enosys()); },
open(path, flags, mode, callback) { callback(enosys()); },
read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
readdir(path, callback) { callback(enosys()); },
readlink(path, callback) { callback(enosys()); },
rename(from, to, callback) { callback(enosys()); },
rmdir(path, callback) { callback(enosys()); },
stat(path, callback) { callback(enosys()); },
symlink(path, link, callback) { callback(enosys()); },
truncate(path, length, callback) { callback(enosys()); },
unlink(path, callback) { callback(enosys()); },
utimes(path, atime, mtime, callback) { callback(enosys()); },
};
}
if (!global.process) {
global.process = {
getuid() { return -1; },
getgid() { return -1; },
geteuid() { return -1; },
getegid() { return -1; },
getgroups() { throw enosys(); },
pid: -1,
ppid: -1,
umask() { throw enosys(); },
cwd() { throw enosys(); },
chdir() { throw enosys(); },
}
}
if (!global.crypto) {
const nodeCrypto = require("crypto");
global.crypto = {
getRandomValues(b) {
nodeCrypto.randomFillSync(b);
},
};
}
if (!global.performance) {
global.performance = {
now() {
const [sec, nsec] = process.hrtime();
return sec * 1000 + nsec / 1000000;
},
};
}
if (!global.TextEncoder) {
global.TextEncoder = require("util").TextEncoder;
}
if (!global.TextDecoder) {
global.TextDecoder = require("util").TextDecoder;
}
// End of polyfills for common API.
const encoder = new TextEncoder("utf-8");
const decoder = new TextDecoder("utf-8");
global.Go = class {
constructor() {
this.argv = ["js"];
this.env = {};
this.exit = (code) => {
if (code !== 0) {
console.warn("exit code:", code);
}
};
this._exitPromise = new Promise((resolve) => {
this._resolveExitPromise = resolve;
});
this._pendingEvent = null;
this._scheduledTimeouts = new Map();
this._nextCallbackTimeoutID = 1;
const setInt64 = (addr, v) => {
this.mem.setUint32(addr + 0, v, true);
this.mem.setUint32(addr + 4, Math.floor(v / 4294967296), true);
}
const getInt64 = (addr) => {
const low = this.mem.getUint32(addr + 0, true);
const high = this.mem.getInt32(addr + 4, true);
return low + high * 4294967296;
}
const loadValue = (addr) => {
const f = this.mem.getFloat64(addr, true);
if (f === 0) {
return undefined;
}
if (!isNaN(f)) {
return f;
}
const id = this.mem.getUint32(addr, true);
return this._values[id];
}
const storeValue = (addr, v) => {
const nanHead = 0x7FF80000;
if (typeof v === "number") {
if (isNaN(v)) {
this.mem.setUint32(addr + 4, nanHead, true);
this.mem.setUint32(addr, 0, true);
return;
}
if (v === 0) {
this.mem.setUint32(addr + 4, nanHead, true);
this.mem.setUint32(addr, 1, true);
return;
}
this.mem.setFloat64(addr, v, true);
return;
}
switch (v) {
case undefined:
this.mem.setFloat64(addr, 0, true);
return;
case null:
this.mem.setUint32(addr + 4, nanHead, true);
this.mem.setUint32(addr, 2, true);
return;
case true:
this.mem.setUint32(addr + 4, nanHead, true);
this.mem.setUint32(addr, 3, true);
return;
case false:
this.mem.setUint32(addr + 4, nanHead, true);
this.mem.setUint32(addr, 4, true);
return;
}
let ref = this._refs.get(v);
if (ref === undefined) {
ref = this._values.length;
this._values.push(v);
this._refs.set(v, ref);
}
let typeFlag = 0;
switch (typeof v) {
case "string":
typeFlag = 1;
break;
case "symbol":
typeFlag = 2;
break;
case "function":
typeFlag = 3;
break;
}
this.mem.setUint32(addr + 4, nanHead | typeFlag, true);
this.mem.setUint32(addr, ref, true);
}
const loadSlice = (addr) => {
const array = getInt64(addr + 0);
const len = getInt64(addr + 8);
return new Uint8Array(this._inst.exports.mem.buffer, array, len);
}
const loadSliceOfValues = (addr) => {
const array = getInt64(addr + 0);
const len = getInt64(addr + 8);
const a = new Array(len);
for (let i = 0; i < len; i++) {
a[i] = loadValue(array + i * 8);
}
return a;
}
const loadString = (addr) => {
const saddr = getInt64(addr + 0);
const len = getInt64(addr + 8);
return decoder.decode(new DataView(this._inst.exports.mem.buffer, saddr, len));
}
const timeOrigin = Date.now() - performance.now();
this.importObject = {
go: {
// Go's SP does not change as long as no Go code is running. Some operations (e.g. calls, getters and setters)
// may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported
// function. A goroutine can switch to a new stack if the current stack is too small (see morestack function).
// This changes the SP, thus we have to update the SP used by the imported function.
// func wasmExit(code int32)
"runtime.wasmExit": (sp) => {
const code = this.mem.getInt32(sp + 8, true);
this.exited = true;
delete this._inst;
delete this._values;
delete this._refs;
this.exit(code);
},
// func wasmWrite(fd uintptr, p unsafe.Pointer, n int32)
"runtime.wasmWrite": (sp) => {
const fd = getInt64(sp + 8);
const p = getInt64(sp + 16);
const n = this.mem.getInt32(sp + 24, true);
fs.writeSync(fd, new Uint8Array(this._inst.exports.mem.buffer, p, n));
},
// func resetMemoryDataView()
"runtime.resetMemoryDataView": (sp) => {
this.mem = new DataView(this._inst.exports.mem.buffer);
},
// func nanotime1() int64
"runtime.nanotime1": (sp) => {
setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000);
},
// func walltime1() (sec int64, nsec int32)
"runtime.walltime1": (sp) => {
const msec = (new Date).getTime();
setInt64(sp + 8, msec / 1000);
this.mem.setInt32(sp + 16, (msec % 1000) * 1000000, true);
},
// func scheduleTimeoutEvent(delay int64) int32
"runtime.scheduleTimeoutEvent": (sp) => {
const id = this._nextCallbackTimeoutID;
this._nextCallbackTimeoutID++;
this._scheduledTimeouts.set(id, setTimeout(
() => {
this._resume();
while (this._scheduledTimeouts.has(id)) {
// for some reason Go failed to register the timeout event, log and try again
// (temporary workaround for https://github.com/golang/go/issues/28975)
console.warn("scheduleTimeoutEvent: missed timeout event");
this._resume();
}
},
getInt64(sp + 8) + 1, // setTimeout has been seen to fire up to 1 millisecond early
));
this.mem.setInt32(sp + 16, id, true);
},
// func clearTimeoutEvent(id int32)
"runtime.clearTimeoutEvent": (sp) => {
const id = this.mem.getInt32(sp + 8, true);
clearTimeout(this._scheduledTimeouts.get(id));
this._scheduledTimeouts.delete(id);
},
// func getRandomData(r []byte)
"runtime.getRandomData": (sp) => {
crypto.getRandomValues(loadSlice(sp + 8));
},
// func stringVal(value string) ref
"syscall/js.stringVal": (sp) => {
storeValue(sp + 24, loadString(sp + 8));
},
// func valueGet(v ref, p string) ref
"syscall/js.valueGet": (sp) => {
const result = Reflect.get(loadValue(sp + 8), loadString(sp + 16));
sp = this._inst.exports.getsp(); // see comment above
storeValue(sp + 32, result);
},
// func valueSet(v ref, p string, x ref)
"syscall/js.valueSet": (sp) => {
Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32));
},
// func valueDelete(v ref, p string)
"syscall/js.valueDelete": (sp) => {
Reflect.deleteProperty(loadValue(sp + 8), loadString(sp + 16));
},
// func valueIndex(v ref, i int) ref
"syscall/js.valueIndex": (sp) => {
storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16)));
},
// valueSetIndex(v ref, i int, x ref)
"syscall/js.valueSetIndex": (sp) => {
Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24));
},
// func valueCall(v ref, m string, args []ref) (ref, bool)
"syscall/js.valueCall": (sp) => {
try {
const v = loadValue(sp + 8);
const m = Reflect.get(v, loadString(sp + 16));
const args = loadSliceOfValues(sp + 32);
const result = Reflect.apply(m, v, args);
sp = this._inst.exports.getsp(); // see comment above
storeValue(sp + 56, result);
this.mem.setUint8(sp + 64, 1);
} catch (err) {
storeValue(sp + 56, err);
this.mem.setUint8(sp + 64, 0);
}
},
// func valueInvoke(v ref, args []ref) (ref, bool)
"syscall/js.valueInvoke": (sp) => {
try {
const v = loadValue(sp + 8);
const args = loadSliceOfValues(sp + 16);
const result = Reflect.apply(v, undefined, args);
sp = this._inst.exports.getsp(); // see comment above
storeValue(sp + 40, result);
this.mem.setUint8(sp + 48, 1);
} catch (err) {
storeValue(sp + 40, err);
this.mem.setUint8(sp + 48, 0);
}
},
// func valueNew(v ref, args []ref) (ref, bool)
"syscall/js.valueNew": (sp) => {
try {
const v = loadValue(sp + 8);
const args = loadSliceOfValues(sp + 16);
const result = Reflect.construct(v, args);
sp = this._inst.exports.getsp(); // see comment above
storeValue(sp + 40, result);
this.mem.setUint8(sp + 48, 1);
} catch (err) {
storeValue(sp + 40, err);
this.mem.setUint8(sp + 48, 0);
}
},
// func valueLength(v ref) int
"syscall/js.valueLength": (sp) => {
setInt64(sp + 16, parseInt(loadValue(sp + 8).length));
},
// valuePrepareString(v ref) (ref, int)
"syscall/js.valuePrepareString": (sp) => {
const str = encoder.encode(String(loadValue(sp + 8)));
storeValue(sp + 16, str);
setInt64(sp + 24, str.length);
},
// valueLoadString(v ref, b []byte)
"syscall/js.valueLoadString": (sp) => {
const str = loadValue(sp + 8);
loadSlice(sp + 16).set(str);
},
// func valueInstanceOf(v ref, t ref) bool
"syscall/js.valueInstanceOf": (sp) => {
this.mem.setUint8(sp + 24, loadValue(sp + 8) instanceof loadValue(sp + 16));
},
// func copyBytesToGo(dst []byte, src ref) (int, bool)
"syscall/js.copyBytesToGo": (sp) => {
const dst = loadSlice(sp + 8);
const src = loadValue(sp + 32);
if (!(src instanceof Uint8Array)) {
this.mem.setUint8(sp + 48, 0);
return;
}
const toCopy = src.subarray(0, dst.length);
dst.set(toCopy);
setInt64(sp + 40, toCopy.length);
this.mem.setUint8(sp + 48, 1);
},
// func copyBytesToJS(dst ref, src []byte) (int, bool)
"syscall/js.copyBytesToJS": (sp) => {
const dst = loadValue(sp + 8);
const src = loadSlice(sp + 16);
if (!(dst instanceof Uint8Array)) {
this.mem.setUint8(sp + 48, 0);
return;
}
const toCopy = src.subarray(0, dst.length);
dst.set(toCopy);
setInt64(sp + 40, toCopy.length);
this.mem.setUint8(sp + 48, 1);
},
"debug": (value) => {
console.log(value);
},
}
};
}
async run(instance) {
this._inst = instance;
this.mem = new DataView(this._inst.exports.mem.buffer);
this._values = [ // TODO: garbage collection
NaN,
0,
null,
true,
false,
global,
this,
];
this._refs = new Map();
this.exited = false;
// Pass command line arguments and environment variables to WebAssembly by writing them to the linear memory.
let offset = 4096;
const strPtr = (str) => {
const ptr = offset;
const bytes = encoder.encode(str + "\0");
new Uint8Array(this.mem.buffer, offset, bytes.length).set(bytes);
offset += bytes.length;
if (offset % 8 !== 0) {
offset += 8 - (offset % 8);
}
return ptr;
};
const argc = this.argv.length;
const argvPtrs = [];
this.argv.forEach((arg) => {
argvPtrs.push(strPtr(arg));
});
argvPtrs.push(0);
const keys = Object.keys(this.env).sort();
keys.forEach((key) => {
argvPtrs.push(strPtr(`${key}=${this.env[key]}`));
});
argvPtrs.push(0);
const argv = offset;
argvPtrs.forEach((ptr) => {
this.mem.setUint32(offset, ptr, true);
this.mem.setUint32(offset + 4, 0, true);
offset += 8;
});
this._inst.exports.run(argc, argv);
if (this.exited) {
this._resolveExitPromise();
}
await this._exitPromise;
}
_resume() {
if (this.exited) {
throw new Error("Go program has already exited");
}
this._inst.exports.resume();
if (this.exited) {
this._resolveExitPromise();
}
}
_makeFuncWrapper(id) {
const go = this;
return function () {
const event = { id: id, this: this, args: arguments };
go._pendingEvent = event;
go._resume();
return event.result;
};
}
}
if (
global.require &&
global.require.main === module &&
global.process &&
global.process.versions &&
!global.process.versions.electron
) {
if (process.argv.length < 3) {
console.error("usage: go_js_wasm_exec [wasm binary] [arguments]");
process.exit(1);
}
const go = new Go();
go.argv = process.argv.slice(2);
go.env = Object.assign({ TMPDIR: require("os").tmpdir() }, process.env);
go.exit = process.exit;
WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
process.on("exit", (code) => { // Node.js exits if no event handler is pending
if (code === 0 && !go.exited) {
// deadlock, make Go print error and stack traces
go._pendingEvent = { id: 0 };
go._resume();
}
});
return go.run(result.instance);
}).catch((err) => {
console.error(err);
process.exit(1);
});
}
})();