Convince OpenBSD developers to allow an executable get the path to itself (2020)

4 months ago 34

OpenBSD takes the prize for the hackiest implementation of std.fs.selfExePath, a function which is readily available on Linux, Darwin/macOS, FreeBSD, DragonFlyBSD, NetBSD, and Microsoft Windows.

	.openbsd => {
	// OpenBSD doesn't support getting the path of a running process, so try to guess it
	if (os.argv.len == 0)
	return error.FileNotFound;

	const argv0 = mem.span(os.argv[0]);
	if (mem.indexOf(u8, argv0, "/") != null) {
	// argv[0] is a path (relative or absolute): use realpath(3) directly
	var real_path_buf: [MAX_PATH_BYTES]u8 = undefined;
	const real_path = try os.realpathZ(os.argv[0], &real_path_buf);
	if (real_path.len > out_buffer.len)
	return error.NameTooLong;
	mem.copy(u8, out_buffer, real_path);
	return out_buffer[0..real_path.len];
	} else if (argv0.len != 0) {
	// argv[0] is not empty (and not a path): search it inside PATH
	const PATH = std.os.getenvZ("PATH") orelse return error.FileNotFound;
	var path_it = mem.tokenize(PATH, &[_]u8{path.delimiter});
	while (path_it.next()) \|a_path\| {
	var resolved_path_buf: [MAX_PATH_BYTES]u8 = undefined;
	const resolved_path = std.fmt.bufPrintZ(&resolved_path_buf, "{s}/{s}", .{
	a_path,
	os.argv[0],
	}) catch continue;

	var real_path_buf: [MAX_PATH_BYTES]u8 = undefined;
	if (os.realpathZ(&resolved_path_buf, &real_path_buf)) \|real_path\| {
	// found a file, and hope it is the right file
	if (real_path.len > out_buffer.len)
	return error.NameTooLong;
	mem.copy(u8, out_buffer, real_path);
	return out_buffer[0..real_path.len];
	} else \|_\| continue;
	}
	}
	return error.FileNotFound;
	},