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// This source code is released into the public domain.
export module nihil.posix:open_in_path;
import nihil.std;
import nihil.error;
import :fd;
import :getenv;
import :open;
import :paths;
namespace nihil {
// Find an executable in the given path, which should be a colon-separated list of directories, and
// open it with O_EXEC. If the file can't be found or can't be opened, returns an appropriate error.
export [[nodiscard]] auto
open_in_path(std::filesystem::path const &file, std::string_view path) -> std::expected<fd, error>
{
// Absolute pathname skips the search.
if (file.is_absolute())
return open(file, open_exec);
// Default to ENOENT as the error.
auto err = error(std::errc::no_such_file_or_directory);
for (auto &&dir : path | std::views::split(':')) {
// An empty $PATH element means cwd.
auto sdir = dir.empty() ? std::filesystem::path(".")
: std::filesystem::path(std::string_view(dir));
if (auto ret = open(sdir / file, open_exec); ret)
return ret;
// If we get an error other than ENOENT, cache it to return to the caller.
// This means we can propagate open() errors.
else if (ret.error().root_cause() != std::errc::no_such_file_or_directory)
err = std::move(ret.error());
}
return std::unexpected(std::move(err));
}
// Find an executable in $PATH and open it. If $PATH is not set, uses _PATH_DEFPATH.
// If the file can't be found or can't be opened, returns an appropriate error.
export [[nodiscard]] auto
open_in_path(std::filesystem::path const &file) -> std::expected<fd, error>
{
auto const path = getenv("PATH").value_or(std::string(paths::defpath)); // NOLINT
return open_in_path(file, path);
}
} // namespace nihil
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