posix: add tempfile()

1 files changed, 71 insertions, 0 deletions

diff --git a/nihil.posix/posix.exec.cc b/nihil.posix/posix.exec.cc
new file mode 100644
index 0000000..5bdcbf7
--- /dev/null
+++ b/nihil.posix/posix.exec.cc
@@ -0,0 +1,71 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+module;
+
+#include <coroutine>
+#include <expected>
+#include <format>
+#include <string>
+#include <utility>
+
+#include <err.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+extern char **environ;
+
+module nihil.posix;
+
+import nihil.error;
+import nihil.monad;
+
+namespace nihil {
+
+fexecv::fexecv(fd &&execfd, argv &&args) noexcept
+	: m_execfd(std::move(execfd))
+	, m_args(std::move(args))
+{
+}
+
+auto fexecv::exec(this fexecv &self)
+	-> std::expected<void, error>
+{
+	::fexecve(self.m_execfd.get(), self.m_args.data(), environ);
+	return std::unexpected(error("fexecve failed",
+				     error(std::errc(errno))));
+}
+	
+fexecv::fexecv(fexecv &&) noexcept = default;
+auto fexecv::operator=(this fexecv &, fexecv &&) noexcept -> fexecv& = default;
+	
+auto execv(std::string_view path, argv &&argv)
+	-> std::expected<fexecv, error>
+{
+	auto file = co_await open(path, O_EXEC)
+		.transform_error([&] (error cause) {
+			return error(std::format("could not open {}", path),
+				     std::move(cause));
+		});
+
+	co_return fexecv(std::move(file), std::move(argv));
+}
+
+auto execvp(std::string_view file, argv &&argv)
+	-> std::expected<fexecv, error>
+{
+	auto execfd = find_in_path(file);
+	if (!execfd)
+		return std::unexpected(error(
+			std::format("executable not found in path: {}", file)));
+	return fexecv(std::move(*execfd), std::move(argv));
+}
+
+auto shell(std::string_view const &command)
+	-> std::expected<fexecv, error>
+{
+	return execl("/bin/sh", "sh", "-c", command);
+}
+
+} // namespace nihil