1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
// This source code is released into the public domain.
module;
#include <unistd.h> // execv()
#include "nihil.hh"
extern char **environ; // NOLINT
export module nihil.posix:execv;
import nihil.std;
import nihil.core;
import :argv;
import :executor;
import :fd;
namespace nihil {
// execv: use a filename and an argument vector to call ::execv().
export struct execv final
{
using tag = exec_tag;
// Construct an execv from a filename.
execv(std::filesystem::path path, argv &&args) noexcept
: m_executable(std::move(path))
, m_args(std::move(args))
{
}
// Construct an execv from a file descriptor
execv(fd &&executable, argv &&argv) noexcept
: m_executable(std::move(executable))
, m_args(std::move(argv))
{
}
~execv() = default;
// Movable
execv(execv &&) noexcept = default;
auto operator=(execv &&) noexcept -> execv & = default;
// Not copyable (because m_args isn't copyable).
execv(execv const &) = delete;
auto operator=(this execv &, execv const &) -> execv & = delete;
// Perform the execv(). This only returns on failure.
[[nodiscard]] auto exec(this execv &self) -> std::expected<void, error>
{
auto guard = save_errno();
// clang-format off
return self.m_executable | match {
[&](std::filesystem::path const &path) {
::execv(path.string().c_str(), self.m_args.data());
return std::unexpected(error("execve failed", error(sys_error())));
},
[&](fd const &file) {
#if NIHIL_HAVE_FEXECVE == 1
::fexecve(file.get(), self.m_args.data(), environ);
return std::unexpected(error("execve failed", error(sys_error())));
#else
std::ignore = file;
return std::unexpected(error(std::errc::function_not_supported));
#endif
}
};
// clang-format on
}
private:
// The thing we will execute.
std::variant<std::filesystem::path, fd> m_executable;
// Arguments to pass to the thing.
argv m_args;
};
} // namespace nihil
|
