lib/cmdline.c

   1 /*
   2  * linux/lib/cmdline.c
   3  * Helper functions generally used for parsing kernel command line
   4  * and module options.
   5  *
   6  * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
   7  *
   8  * This source code is licensed under the GNU General Public License,
   9  * Version 2.  See the file COPYING for more details.
  10  *
  11  * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18
  19
  20 /**
  21  *      get_option - Parse integer from an option string
  22  *      @str: option string
  23  *      @pint: (output) integer value parsed from @str
  24  *
  25  *      Read an int from an option string; if available accept a subsequent
  26  *      comma as well.
  27  *
  28  *      Return values:
  29  *      0 : no int in string
  30  *      1 : int found, no subsequent comma
  31  *      2 : int found including a subsequent comma
  32  */
  33
  34 int get_option (char **str, int *pint)
  35 {
  36         char *cur = *str;
  37
  38         if (!cur || !(*cur))
  39                 return 0;
  40         *pint = simple_strtol (cur, str, 0);
  41         if (cur == *str)
  42                 return 0;
  43         if (**str == ',') {
  44                 (*str)++;
  45                 return 2;
  46         }
  47
  48         return 1;
  49 }
  50
  51 /**
  52  *      get_options - Parse a string into a list of integers
  53  *      @str: String to be parsed
  54  *      @nints: size of integer array
  55  *      @ints: integer array
  56  *
  57  *      This function parses a string containing a comma-separated
  58  *      list of integers.  The parse halts when the array is
  59  *      full, or when no more numbers can be retrieved from the
  60  *      string.
  61  *
  62  *      Return value is the character in the string which caused
  63  *      the parse to end (typically a null terminator, if @str is
  64  *      completely parseable).
  65  */
  66
  67 char *get_options(const char *str, int nints, int *ints)
  68 {
  69         int res, i = 1;
  70
  71         while (i < nints) {
  72                 res = get_option ((char **)&str, ints + i);
  73                 if (res == 0)
  74                         break;
  75                 i++;
  76                 if (res == 1)
  77                         break;
  78         }
  79         ints[0] = i - 1;
  80         return (char *)str;
  81 }
  82
  83 /**
  84  *      memparse - parse a string with mem suffixes into a number
  85  *      @ptr: Where parse begins
  86  *      @retptr: (output) Pointer to next char after parse completes
  87  *
  88  *      Parses a string into a number.  The number stored at @ptr is
  89  *      potentially suffixed with %K (for kilobytes, or 1024 bytes),
  90  *      %M (for megabytes, or 1048576 bytes), or %G (for gigabytes, or
  91  *      1073741824).  If the number is suffixed with K, M, or G, then
  92  *      the return value is the number multiplied by one kilobyte, one
  93  *      megabyte, or one gigabyte, respectively.
  94  */
  95
  96 unsigned long long memparse (char *ptr, char **retptr)
  97 {
  98         unsigned long long ret = simple_strtoull (ptr, retptr, 0);
  99
 100         switch (**retptr) {
 101         case 'G':
 102         case 'g':
 103                 ret <<= 10;
 104         case 'M':
 105         case 'm':
 106                 ret <<= 10;
 107         case 'K':
 108         case 'k':
 109                 ret <<= 10;
 110                 (*retptr)++;
 111         default:
 112                 break;
 113         }
 114         return ret;
 115 }
 116
 117
 118 EXPORT_SYMBOL(memparse);
 119 EXPORT_SYMBOL(get_option);
 120 EXPORT_SYMBOL(get_options);