drivers/staging/ncpfs/getopt.c

   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  */
  29 int 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 }