Userspace: Implement getopt for testing libc getopt()

userspace/CMakeLists.txt

@@ -10,6 +10,7 @@ set(USERSPACE_PROJECTS
 	dd
 	dhcp-client
 	echo
+	getopt
 	id
 	image
 	init

userspace/getopt/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(getopt CXX)
+
+set(SOURCES
+	main.cpp
+)
+
+add_executable(getopt ${SOURCES})
+target_compile_options(getopt PUBLIC -O2 -g)
+target_link_libraries(getopt PUBLIC libc ban)
+
+add_custom_target(getopt-install
+	COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/getopt ${BANAN_BIN}/
+	DEPENDS getopt
+)

userspace/getopt/main.cpp

@@ -0,0 +1,44 @@
+#include <BAN/String.h>
+#include <BAN/Vector.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+	if (argc < 2)
+	{
+		fprintf(stderr, "usage: %s OPTSTRING [PARAMETERS]...", argv[0]);
+		return 1;
+	}
+
+	BAN::Vector<char*> argv_copy(argc - 1);
+	argv_copy[0] = argv[0];
+	for (int i = 2; i < argc; i++)
+		argv_copy[i - 1] = argv[i];
+
+	int opt;
+	BAN::String parsed;
+	while ((opt = getopt(argc - 1, argv_copy.data(), argv[1])) != -1)
+	{
+		if (opt == ':' || opt == '?')
+			continue;
+
+		MUST(parsed.append(" -"));
+		MUST(parsed.push_back(opt));
+
+		if (optarg)
+		{
+			MUST(parsed.push_back(' '));
+			MUST(parsed.append(optarg));
+		}
+
+		optarg = nullptr;
+	}
+
+	printf("%s --", parsed.data());
+	for (; optind < argc - 1; optind++)
+		printf(" %s", argv_copy[optind]);
+	printf("\n");
+
+	return 0;
+}