lib/parser.c

   1 /*
   2  * lib/parser.c - simple parser for mount, etc. options.
   3  *
   4  * This source code is licensed under the GNU General Public License,
   5  * Version 2.  See the file COPYING for more details.
   6  */
   7
   8 #include <linux/ctype.h>
   9 #include <linux/module.h>
  10 #include <linux/parser.h>
  11 #include <linux/slab.h>
  12 #include <linux/string.h>
  13
  14 static int match_one(char *s, char *p, substring_t args[])
  15 {
  16         char *meta;
  17         int argc = 0;
  18
  19         if (!p)
  20                 return 1;
  21
  22         while(1) {
  23                 int len = -1;
  24                 meta = strchr(p, '%');
  25                 if (!meta)
  26                         return strcmp(p, s) == 0;
  27
  28                 if (strncmp(p, s, meta-p))
  29                         return 0;
  30
  31                 s += meta - p;
  32                 p = meta + 1;
  33
  34                 if (isdigit(*p))
  35                         len = simple_strtoul(p, &p, 10);
  36                 else if (*p == '%') {
  37                         if (*s++ != '%')
  38                                 return 0;
  39                         continue;
  40                 }
  41
  42                 if (argc >= MAX_OPT_ARGS)
  43                         return 0;
  44
  45                 args[argc].from = s;
  46                 switch (*p++) {
  47                 case 's':
  48                         if (len == -1 || len > strlen(s))
  49                                 len = strlen(s);
  50                         args[argc].to = s + len;
  51                         break;
  52                 case 'd':
  53                         simple_strtol(s, &args[argc].to, 0);
  54                         goto num;
  55                 case 'u':
  56                         simple_strtoul(s, &args[argc].to, 0);
  57                         goto num;
  58                 case 'o':
  59                         simple_strtoul(s, &args[argc].to, 8);
  60                         goto num;
  61                 case 'x':
  62                         simple_strtoul(s, &args[argc].to, 16);
  63                 num:
  64                         if (args[argc].to == args[argc].from)
  65                                 return 0;
  66                         break;
  67                 default:
  68                         return 0;
  69                 }
  70                 s = args[argc].to;
  71                 argc++;
  72         }
  73 }
  74
  75 int match_token(char *s, match_table_t table, substring_t args[])
  76 {
  77         struct match_token *p;
  78
  79         for (p = table; !match_one(s, p->pattern, args) ; p++)
  80                 ;
  81
  82         return p->token;
  83 }
  84
  85 static int match_number(substring_t *s, int *result, int base)
  86 {
  87         char *endp;
  88         char *buf;
  89         int ret;
  90
  91         buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
  92         if (!buf)
  93                 return -ENOMEM;
  94         memcpy(buf, s->from, s->to - s->from);
  95         buf[s->to - s->from] = '\0';
  96         *result = simple_strtol(buf, &endp, base);
  97         ret = 0;
  98         if (endp == buf)
  99                 ret = -EINVAL;
 100         kfree(buf);
 101         return ret;
 102 }
 103
 104 int match_int(substring_t *s, int *result)
 105 {
 106         return match_number(s, result, 0);
 107 }
 108
 109 int match_octal(substring_t *s, int *result)
 110 {
 111         return match_number(s, result, 8);
 112 }
 113
 114 int match_hex(substring_t *s, int *result)
 115 {
 116         return match_number(s, result, 16);
 117 }
 118
 119 void match_strcpy(char *to, substring_t *s)
 120 {
 121         memcpy(to, s->from, s->to - s->from);
 122         to[s->to - s->from] = '\0';
 123 }
 124
 125 char *match_strdup(substring_t *s)
 126 {
 127         char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL);
 128         if (p)
 129                 match_strcpy(p, s);
 130         return p;
 131 }
 132
 133 EXPORT_SYMBOL(match_token);
 134 EXPORT_SYMBOL(match_int);
 135 EXPORT_SYMBOL(match_octal);
 136 EXPORT_SYMBOL(match_hex);
 137 EXPORT_SYMBOL(match_strcpy);
 138 EXPORT_SYMBOL(match_strdup);