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