1 files changed, 130 insertions, 0 deletions
diff --git a/include/getopt.h b/include/getopt.h
new file mode 100644
index 0000000000..6f5811e64b
--- /dev/null
+++ b/include/getopt.h
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * getopt.h - a simple getopt(3) implementation.
+ *
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ * Copyright (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ */
+
+#ifndef __GETOPT_H
+#define __GETOPT_H
+
+/**
+ * struct getopt_state - Saved state across getopt() calls
+ */
+struct getopt_state {
+	/**
+	 * @index: Index of the next unparsed argument of @argv. If getopt() has
+	 * parsed all of @argv, then @index will equal @argc.
+	 */
+	int index;
+	/* private: */
+	/** @arg_index: Index within the current argument */
+	int arg_index;
+	union {
+		/* public: */
+		/**
+		 * @opt: Option being parsed when an error occurs. @opt is only
+		 * valid when getopt() returns ``?`` or ``:``.
+		 */
+		int opt;
+		/**
+		 * @arg: The argument to an option, NULL if there is none. @arg
+		 * is only valid when getopt() returns an option character.
+		 */
+		char *arg;
+	/* private: */
+	};
+};
+
+/**
+ * getopt_init_state() - Initialize a &struct getopt_state
+ * @gs: The state to initialize
+ *
+ * This must be called before using @gs with getopt().
+ */
+void getopt_init_state(struct getopt_state *gs);
+
+int __getopt(struct getopt_state *gs, int argc, char *const argv[],
+	     const char *optstring, bool silent);
+
+/**
+ * getopt() - Parse short command-line options
+ * @gs: Internal state and out-of-band return arguments. This must be
+ *      initialized with getopt_init_context() beforehand.
+ * @argc: Number of arguments, not including the %NULL terminator
+ * @argv: Argument list, terminated by %NULL
+ * @optstring: Option specification, as described below
+ *
+ * getopt() parses short options. Short options are single characters. They may
+ * be followed by a required argument or an optional argument. Arguments to
+ * options may occur in the same argument as an option (like ``-larg``), or
+ * in the following argument (like ``-l arg``). An argument containing
+ * options begins with a ``-``. If an option expects no arguments, then it may
+ * be immediately followed by another option (like ``ls -alR``).
+ *
+ * @optstring is a list of accepted options. If an option is followed by ``:``
+ * in @optstring, then it expects a mandatory argument. If an option is followed
+ * by ``::`` in @optstring, it expects an optional argument. @gs.arg points
+ * to the argument, if one is parsed.
+ *
+ * getopt() stops parsing options when it encounters the first non-option
+ * argument, when it encounters the argument ``--``, or when it runs out of
+ * arguments. For example, in ``ls -l foo -R``, option parsing will stop when
+ * getopt() encounters ``foo``, if ``l`` does not expect an argument. However,
+ * the whole list of arguments would be parsed if ``l`` expects an argument.
+ *
+ * An example invocation of getopt() might look like::
+ *
+ *     char *argv[] = { "program", "-cbx", "-a", "foo", "bar", 0 };
+ *     int opt, argc = ARRAY_SIZE(argv) - 1;
+ *     struct getopt_state gs;
+ *
+ *     getopt_init_state(&gs);
+ *     while ((opt = getopt(&gs, argc, argv, "a::b:c")) != -1)
+ *         printf("opt = %c, index = %d, arg = \"%s\"\n", opt, gs.index, gs.arg);
+ *     printf("%d argument(s) left\n", argc - gs.index);
+ *
+ * and would produce an output of::
+ *
+ *     opt = c, index = 1, arg = "<NULL>"
+ *     opt = b, index = 2, arg = "x"
+ *     opt = a, index = 4, arg = "foo"
+ *     1 argument(s) left
+ *
+ * For further information, refer to the getopt(3) man page.
+ *
+ * Return:
+ * * An option character if an option is found. @gs.arg is set to the
+ *   argument if there is one, otherwise it is set to ``NULL``.
+ * * ``-1`` if there are no more options, if a non-option argument is
+ *   encountered, or if an ``--`` argument is encountered.
+ * * ``'?'`` if we encounter an option not in @optstring. @gs.opt is set to
+ *   the unknown option.
+ * * ``':'`` if an argument is required, but no argument follows the
+ *   option. @gs.opt is set to the option missing its argument.
+ *
+ * @gs.index is always set to the index of the next unparsed argument in @argv.
+ */
+static inline int getopt(struct getopt_state *gs, int argc,
+			 char *const argv[], const char *optstring)
+{
+	return __getopt(gs, argc, argv, optstring, false);
+}
+
+/**
+ * getopt_silent() - Parse short command-line options silently
+ * @gs: State
+ * @argc: Argument count
+ * @argv: Argument list
+ * @optstring: Option specification
+ *
+ * Same as getopt(), except no error messages are printed.
+ */
+static inline int getopt_silent(struct getopt_state *gs, int argc,
+				char *const argv[], const char *optstring)
+{
+	return __getopt(gs, argc, argv, optstring, true);
+}
+
+#endif /* __GETOPT_H */