1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * getopt.c
 4 */
 5
 6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 7
 8#include <linux/kernel.h>
 9#include <linux/string.h>
10
11#include <asm/errno.h>
12
13#include "getopt.h"
14
15/**
16 *	ncp_getopt - option parser
17 *	@caller: name of the caller, for error messages
18 *	@options: the options string
19 *	@opts: an array of &struct option entries controlling parser operations
20 *	@optopt: output; will contain the current option
21 *	@optarg: output; will contain the value (if one exists)
22 *	@value: output; may be NULL; will be overwritten with the integer value
23 *		of the current argument.
24 *
25 *	Helper to parse options on the format used by mount ("a=b,c=d,e,f").
26 *	Returns opts->val if a matching entry in the 'opts' array is found,
27 *	0 when no more tokens are found, -1 if an error is encountered.
28 */
29int ncp_getopt(const char *caller, char **options, const struct ncp_option *opts,
30	       char **optopt, char **optarg, unsigned long *value)
31{
32	char *token;
33	char *val;
34
35	do {
36		if ((token = strsep(options, ",")) == NULL)
37			return 0;
38	} while (*token == '\0');
39	if (optopt)
40		*optopt = token;
41
42	if ((val = strchr (token, '=')) != NULL) {
43		*val++ = 0;
44	}
45	*optarg = val;
46	for (; opts->name; opts++) {
47		if (!strcmp(opts->name, token)) {
48			if (!val) {
49				if (opts->has_arg & OPT_NOPARAM) {
50					return opts->val;
51				}
52				pr_info("%s: the %s option requires an argument\n",
53					caller, token);
54				return -EINVAL;
55			}
56			if (opts->has_arg & OPT_INT) {
57				int rc = kstrtoul(val, 0, value);
58
59				if (rc) {
60					pr_info("%s: invalid numeric value in %s=%s\n",
61						caller, token, val);
62					return rc;
63				}
64				return opts->val;
65			}
66			if (opts->has_arg & OPT_STRING) {
67				return opts->val;
68			}
69			pr_info("%s: unexpected argument %s to the %s option\n",
70				caller, val, token);
71			return -EINVAL;
72		}
73	}
74	pr_info("%s: Unrecognized mount option %s\n", caller, token);
75	return -EOPNOTSUPP;
76}