From ecba83520d4c34870e0f5f0997d59d4496957240 Mon Sep 17 00:00:00 2001
From: Richard Musiol <mail@richard-musiol.de>
Date: Tue, 8 Oct 2019 00:58:26 +0200
Subject: 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>
---
 misc/wasm/wasm_exec.js | 60 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 14 deletions(-)

(limited to 'misc')

diff --git a/misc/wasm/wasm_exec.js b/misc/wasm/wasm_exec.js
index 9ffa9201e8..3c2c186867 100644
--- a/misc/wasm/wasm_exec.js
+++ b/misc/wasm/wasm_exec.js
@@ -30,6 +30,12 @@
 		global.fs = require("fs");
 	}
 
+	const enosys = () => {
+		const err = new Error("not implemented");
+		err.code = "ENOSYS";
+		return err;
+	};
+
 	if (!global.fs) {
 		let outputBuf = "";
 		global.fs = {
@@ -45,27 +51,53 @@
 			},
 			write(fd, buf, offset, length, position, callback) {
 				if (offset !== 0 || length !== buf.length || position !== null) {
-					throw new Error("not implemented");
+					callback(enosys());
+					return;
 				}
 				const n = this.writeSync(fd, buf);
 				callback(null, n);
 			},
-			open(path, flags, mode, callback) {
-				const err = new Error("not implemented");
-				err.code = "ENOSYS";
-				callback(err);
-			},
-			read(fd, buffer, offset, length, position, callback) {
-				const err = new Error("not implemented");
-				err.code = "ENOSYS";
-				callback(err);
-			},
-			fsync(fd, callback) {
-				callback(null);
-			},
+			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 = {
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