shell: remove usage of .spawn

src/shell.js

@@ -8,12 +8,11 @@ const assert = require('assert'),
     util = require('util');
 
 exports = module.exports = {
-    spawn,
-    exec,
     sudo,
 
     promises: {
         exec: util.promisify(exec),
+        execFile: util.promisify(execFile),
         spawn: util.promisify(spawn),
         sudo: util.promisify(sudo)
     }
@@ -21,6 +20,7 @@ exports = module.exports = {
 
 const SUDO = '/usr/bin/sudo';
 
+// default encoding utf8, shell, handles input. full command
 function exec(tag, cmd, options, callback) {
     assert.strictEqual(typeof tag, 'string');
     assert.strictEqual(typeof cmd, 'string');
@@ -29,6 +29,7 @@ function exec(tag, cmd, options, callback) {
 
     debug(`${tag} exec: ${cmd}`);
 
+    // https://github.com/nodejs/node/issues/25231
     const cp = child_process.exec(cmd, options, function (error, stdout, stderr) {
         let e = null;
         if (error) {
@@ -48,6 +49,36 @@ function exec(tag, cmd, options, callback) {
     }
 }
 
+// no shell, utf8 encoding, separate args
+function execFile(tag, file, args, options, callback) {
+    assert.strictEqual(typeof tag, 'string');
+    assert.strictEqual(typeof file, 'string');
+    assert(Array.isArray(args));
+    assert.strictEqual(typeof options, 'object');
+    assert.strictEqual(typeof callback, 'function');
+
+    debug(`${tag} exec: ${file}`);
+
+    // https://github.com/nodejs/node/issues/25231
+    const cp = child_process.execFile(file, args, options, function (error, stdout, stderr) {
+        let e = null;
+        if (error) {
+            e = new BoxError(BoxError.SHELL_ERROR, `${tag} errored with code ${error.code} message ${error.message}`);
+            e.stdout = stdout; // when promisified, this is the way to get stdout
+            e.stderr = stderr; // when promisified, this is the way to get stderr
+
+            debug(`${tag}: ${file} with args ${args.join(' ')} errored`, error);
+        }
+
+        callback(e, stdout);
+    });
+
+    if (options.input) {
+        cp.stdin.write(options.input);
+        cp.stdin.end();
+    }
+}
+
 // use this when you are afraid of how arguments will split up
 function spawn(tag, file, args, options, callback) {
     assert.strictEqual(typeof tag, 'string');