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 #define _MINIX 1
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <minix/config.h>
  19 #include <minix/const.h>
  20 #include <minix/optset.h>
  21
  22 static void optset_parse_entry(struct optset *entry, char *ptr, int
  23         len);
  24
  25 /*===========================================================================*
  26  *                              optset_parse_entry                           *
  27  *===========================================================================*/
  28 static void optset_parse_entry(entry, ptr, len)
  29 struct optset *entry;
  30 char *ptr;
  31 int len;
  32 {
  33 /* Parse and store the value of a single option.
  34  */
  35   char *dst;
  36   int val;
  37
  38   switch (entry->os_type) {
  39   case OPT_BOOL:
  40         *((int *) entry->os_ptr) = entry->os_val;
  41
  42         break;
  43
  44   case OPT_STRING:
  45         if (len >= entry->os_val)
  46                 len = entry->os_val - 1;
  47
  48         dst = (char *) entry->os_ptr;
  49
  50         if (len > 0)
  51                 memcpy(dst, ptr, len);
  52         dst[len] = 0;
  53
  54         break;
  55
  56   case OPT_INT:
  57         if (len > 0)
  58                 val = (int) strtoul(ptr, NULL, entry->os_val);
  59         else
  60                 val = 0;
  61
  62         *((int *) entry->os_ptr) = val;
  63
  64         break;
  65   }
  66 }
  67
  68 /*===========================================================================*
  69  *                              optset_parse                                 *
  70  *===========================================================================*/
  71 void optset_parse(table, string)
  72 struct optset *table;
  73 char *string;
  74 {
  75 /* Parse a string of options, using the provided table of optset entries.
  76  */
  77   char *p, *kptr, *vptr;
  78   int i, klen, vlen;
  79
  80   for (p = string; *p; ) {
  81         /* Get the key name for the field. */
  82         for (kptr = p, klen = 0; *p && *p != '=' && *p != ','; p++, klen++);
  83
  84         if (*p == '=') {
  85                 /* The field has an associated value. */
  86                 vptr = ++p;
  87
  88                 /* If the first character after the '=' is a quote character,
  89                  * find a matching quote character followed by either a comma
  90                  * or the terminating null character, and use the string in
  91                  * between. Otherwise, use the string up to the next comma or
  92                  * the terminating null character.
  93                  */
  94                 if (*p == '\'' || *p == '"') {
  95                         p++;
  96
  97                         for (vlen = 0; *p && (*p != *vptr ||
  98                                 (p[1] && p[1] != ',')); p++, vlen++);
  99
 100                         if (*p) p++;
 101                         vptr++;
 102                 }
 103                 else
 104                         for (vlen = 0; *p && *p != ','; p++, vlen++);
 105         }
 106         else {
 107                 vptr = NULL;
 108                 vlen = 0;
 109         }
 110
 111         if (*p == ',') p++;
 112
 113         /* Find a matching entry for this key in the given table. If found,
 114          * call optset_parse_entry() on it. Silently ignore the option
 115          * otherwise.
 116          */
 117         for (i = 0; table[i].os_name != NULL; i++) {
 118                 if ((int) strlen(table[i].os_name) == klen &&
 119                         !strncasecmp(table[i].os_name, kptr, klen)) {
 120
 121                         optset_parse_entry(&table[i], vptr, vlen);
 122
 123                         break;
 124                 }
 125         }
 126   }
 127 }