balena-cli/lib/utils/which.ts
Paulo Castro eeb2be2912 ssh: Attempt cloud username if 'root' authentication fails
Also refactor several files to avoid code duplication.

Change-type: minor
2022-02-12 02:40:35 +00:00

98 lines
3.0 KiB
TypeScript

/**
* @license
* Copyright 2021 Balena Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { promises as fs, constants } from 'fs';
import * as path from 'path';
export const { F_OK, R_OK, W_OK, X_OK } = constants;
export async function exists(filename: string, mode = F_OK) {
try {
await fs.access(filename, mode);
return true;
} catch {
return false;
}
}
/**
* Replace sequences of untowardly characters like /[<>:"/\\|?*\u0000-\u001F]/g
* and '.' or '..' with an underscore, plus other rules enforced by the filenamify
* package. See https://github.com/sindresorhus/filenamify/
*/
export function sanitizePath(filepath: string) {
const filenamify = require('filenamify') as typeof import('filenamify');
// normalize also converts forward slash to backslash on Windows
return path
.normalize(filepath)
.split(path.sep)
.map((f) => filenamify(f, { replacement: '_' }))
.join(path.sep);
}
/**
* Given a program name like 'mount', search for it in a pre-defined set of
* folders ('/usr/bin', '/bin', '/usr/sbin', '/sbin') and return the full path if found.
*
* For executables, in some scenarios, this can be more secure than allowing
* any folder in the PATH. Only relevant on Linux or macOS.
*/
export async function whichBin(programName: string): Promise<string> {
for (const dir of ['/usr/bin', '/bin', '/usr/sbin', '/sbin']) {
const candidate = path.join(dir, programName);
if (await exists(candidate, X_OK)) {
return candidate;
}
}
return '';
}
/**
* Error handling wrapper around the npm `which` package:
* "Like the unix which utility. Finds the first instance of a specified
* executable in the PATH environment variable. Does not cache the results,
* so hash -r is not needed when the PATH changes."
*
* @param program Basename of a program, for example 'ssh'
* @param rejectOnMissing If the program cannot be found, reject the promise
* with an ExpectedError instead of fulfilling it with an empty string.
* @returns The program's full path, e.g. 'C:\WINDOWS\System32\OpenSSH\ssh.EXE'
*/
export async function which(
program: string,
rejectOnMissing = true,
): Promise<string> {
const whichMod = await import('which');
let programPath: string;
try {
programPath = await whichMod(program);
} catch (err) {
if (err.code === 'ENOENT') {
if (rejectOnMissing) {
const { ExpectedError } = await import('../errors');
throw new ExpectedError(
`'${program}' program not found. Is it installed?`,
);
} else {
return '';
}
}
throw err;
}
return programPath;
}