lib/libsys/optset.c

   1 /* This file provides functionality to parse strings of comma-separated
   2  * options, each being either a single key name or a key=value pair, where the
   3  * value may be enclosed in quotes. A table of optset entries is provided to
   4  * determine which options are recognized, how to parse their values, and where
   5  * to store those. Unrecognized options are silently ignored; improperly
   6  * formatted options are silently set to reasonably acceptable values.
   7  *
   8  * The entry points into this file are:
   9  *   optset_parse       parse the given options string using the given table
  10  *
  11  * Created:
  12  *   May 2009 (D.C. van Moolenbroek)
  13  */
  14
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <minix/config.h>
  18 #include <minix/const.h>
  19 #include <minix/optset.h>
  20
  21 static void optset_parse_entry(struct optset *entry, char *ptr, int len);
  22
  23 /*===========================================================================*
  24  *                              optset_parse_entry                           *
  25  *===========================================================================*/
  26 static void optset_parse_entry(struct optset *entry, char *ptr, int len)
  27 {
  28 /* Parse and store the value of a single option.
  29  */
  30   char *dst;
  31   int val;
  32
  33   switch (entry->os_type) {
  34   case OPT_BOOL:
  35         *((int *) entry->os_ptr) = entry->os_val;
  36
  37         break;
  38
  39   case OPT_STRING:
  40         if (len >= entry->os_val)
  41                 len = entry->os_val - 1;
  42
  43         dst = (char *) entry->os_ptr;
  44
  45         if (len > 0)
  46                 memcpy(dst, ptr, len);
  47         dst[len] = 0;
  48
  49         break;
  50
  51   case OPT_INT:
  52         if (len > 0)
  53                 val = (int) strtoul(ptr, NULL, entry->os_val);
  54         else
  55                 val = 0;
  56
  57         *((int *) entry->os_ptr) = val;
  58
  59         break;
  60   }
  61 }
  62
  63 /*===========================================================================*
  64  *                              optset_parse                                 *
  65  *===========================================================================*/
  66 void optset_parse(struct optset *table, char *string)
  67 {
  68 /* Parse a string of options, using the provided table of optset entries.
  69  */
  70   char *p, *kptr, *vptr;
  71   int i, klen, vlen;
  72
  73   for (p = string; *p; ) {
  74         /* Get the key name for the field. */
  75         for (kptr = p, klen = 0; *p && *p != '=' && *p != ','; p++, klen++);
  76
  77         if (*p == '=') {
  78                 /* The field has an associated value. */
  79                 vptr = ++p;
  80
  81                 /* If the first character after the '=' is a quote character,
  82                  * find a matching quote character followed by either a comma
  83                  * or the terminating null character, and use the string in
  84                  * between. Otherwise, use the string up to the next comma or
  85                  * the terminating null character.
  86                  */
  87                 if (*p == '\'' || *p == '"') {
  88                         p++;
  89
  90                         for (vlen = 0; *p && (*p != *vptr ||
  91                                 (p[1] && p[1] != ',')); p++, vlen++);
  92
  93                         if (*p) p++;
  94                         vptr++;
  95                 }
  96                 else
  97                         for (vlen = 0; *p && *p != ','; p++, vlen++);
  98         }
  99         else {
 100                 vptr = NULL;
 101                 vlen = 0;
 102         }
 103
 104         if (*p == ',') p++;
 105
 106         /* Find a matching entry for this key in the given table. If found,
 107          * call optset_parse_entry() on it. Silently ignore the option
 108          * otherwise.
 109          */
 110         for (i = 0; table[i].os_name != NULL; i++) {
 111                 if ((int) strlen(table[i].os_name) == klen &&
 112                         !strncasecmp(table[i].os_name, kptr, klen)) {
 113
 114                         optset_parse_entry(&table[i], vptr, vlen);
 115
 116                         break;
 117                 }
 118         }
 119   }
 120 }