1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/**
18 * `Shell` provides a collection of functions to use with `Subprocess` that make
19 * it easier to safely run processes in a unix shell.
20 *
21 * Note: use this rarely and carefully. By default you should use `Subprocess`
22 * with a vector of arguments.
23 */
24
25#pragma once
26
27#include <string>
28#include <vector>
29
30#include <folly/Conv.h>
31#include <folly/Format.h>
32#include <folly/Range.h>
33
34namespace folly {
35
36/**
37 * Quotes an argument to make it suitable for use as shell command arguments.
38 */
39std::string shellQuote(StringPiece argument);
40
41namespace detail {
42template <typename... Arguments>
43std::vector<std::string> shellify(
44 StringPiece format,
45 Arguments&&... arguments) {
46 auto command = sformat(
47 format,
48 shellQuote(to<std::string>(std::forward<Arguments>(arguments)))...);
49 return {"/bin/sh", "-c", command};
50}
51
52struct ShellCmdFormat {
53 StringPiece format;
54 template <typename... Arguments>
55 std::vector<std::string> operator()(Arguments&&... arguments) const {
56 return ::folly::detail::shellify(
57 format, std::forward<Arguments>(arguments)...);
58 }
59};
60
61} // namespace detail
62
63inline namespace literals {
64inline namespace shell_literals {
65constexpr detail::ShellCmdFormat operator"" _shellify(
66 char const* name,
67 std::size_t length) {
68 return {folly::StringPiece(name, length)};
69}
70} // namespace shell_literals
71} // namespace literals
72
73/**
74 * Create argument array for `Subprocess()` for a process running in a
75 * shell.
76 *
77 * The shell to use is always going to be `/bin/sh`.
78 *
79 * This is deprecated in favour of the user-defined-literal `_shellify`
80 * from namespace `folly::shell_literals` because that requires that the format
81 * string is a compile-time constant which can be inspected during code reviews
82 */
83// clang-format off
84template <typename... Arguments>
85[[deprecated(
86 "Use `\"command {} {} ...\"_shellify(argument1, argument2 ...)` from "
87 "namespace `folly::literals::shell_literals`")]]
88std::vector<std::string> shellify(
89 StringPiece format,
90 Arguments&&... arguments) {
91 return detail::shellify(format, std::forward<Arguments>(arguments)...);
92}
93// clang-format on
94
95} // namespace folly
96