1 files changed, 76 insertions, 0 deletions
diff --git a/drivers/staging/ncpfs/getopt.c b/drivers/staging/ncpfs/getopt.c
new file mode 100644
index 000000000000..5c941bef14c4
--- /dev/null
+++ b/drivers/staging/ncpfs/getopt.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * getopt.c
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#include <asm/errno.h>
+
+#include "getopt.h"
+
+/**
+ *	ncp_getopt - option parser
+ *	@caller: name of the caller, for error messages
+ *	@options: the options string
+ *	@opts: an array of &struct option entries controlling parser operations
+ *	@optopt: output; will contain the current option
+ *	@optarg: output; will contain the value (if one exists)
+ *	@value: output; may be NULL; will be overwritten with the integer value
+ *		of the current argument.
+ *
+ *	Helper to parse options on the format used by mount ("a=b,c=d,e,f").
+ *	Returns opts->val if a matching entry in the 'opts' array is found,
+ *	0 when no more tokens are found, -1 if an error is encountered.
+ */
+int ncp_getopt(const char *caller, char **options, const struct ncp_option *opts,
+	       char **optopt, char **optarg, unsigned long *value)
+{
+	char *token;
+	char *val;
+
+	do {
+		if ((token = strsep(options, ",")) == NULL)
+			return 0;
+	} while (*token == '\0');
+	if (optopt)
+		*optopt = token;
+
+	if ((val = strchr (token, '=')) != NULL) {
+		*val++ = 0;
+	}
+	*optarg = val;
+	for (; opts->name; opts++) {
+		if (!strcmp(opts->name, token)) {
+			if (!val) {
+				if (opts->has_arg & OPT_NOPARAM) {
+					return opts->val;
+				}
+				pr_info("%s: the %s option requires an argument\n",
+					caller, token);
+				return -EINVAL;
+			}
+			if (opts->has_arg & OPT_INT) {
+				int rc = kstrtoul(val, 0, value);
+
+				if (rc) {
+					pr_info("%s: invalid numeric value in %s=%s\n",
+						caller, token, val);
+					return rc;
+				}
+				return opts->val;
+			}
+			if (opts->has_arg & OPT_STRING) {
+				return opts->val;
+			}
+			pr_info("%s: unexpected argument %s to the %s option\n",
+				caller, val, token);
+			return -EINVAL;
+		}
+	}
+	pr_info("%s: Unrecognized mount option %s\n", caller, token);
+	return -EOPNOTSUPP;
+}