/*
   * 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
  ",
  					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
  ",
  						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
  ",

  				caller, val, token);
  			return -EINVAL;
  		}
  	}

  	pr_info("%s: Unrecognized mount option %s
  ", caller, token);

  	return -EOPNOTSUPP;
  }