linux/lib/cmdline.c
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   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 *      If a hyphen was found in get_option, this will handle the
  21 *      range of numbers, M-N.  This will expand the range and insert
  22 *      the values[M, M+1, ..., N] into the ints array in get_options.
  23 */
  24
  25static int get_range(char **str, int *pint)
  26{
  27        int x, inc_counter, upper_range;
  28
  29        (*str)++;
  30        upper_range = simple_strtol((*str), NULL, 0);
  31        inc_counter = upper_range - *pint;
  32        for (x = *pint; x < upper_range; x++)
  33                *pint++ = x;
  34        return inc_counter;
  35}
  36
  37/**
  38 *      get_option - Parse integer from an option string
  39 *      @str: option string
  40 *      @pint: (output) integer value parsed from @str
  41 *
  42 *      Read an int from an option string; if available accept a subsequent
  43 *      comma as well.
  44 *
  45 *      Return values:
  46 *      0 - no int in string
  47 *      1 - int found, no subsequent comma
  48 *      2 - int found including a subsequent comma
  49 *      3 - hyphen found to denote a range
  50 */
  51
  52int get_option (char **str, int *pint)
  53{
  54        char *cur = *str;
  55
  56        if (!cur || !(*cur))
  57                return 0;
  58        *pint = simple_strtol (cur, str, 0);
  59        if (cur == *str)
  60                return 0;
  61        if (**str == ',') {
  62                (*str)++;
  63                return 2;
  64        }
  65        if (**str == '-')
  66                return 3;
  67
  68        return 1;
  69}
  70
  71/**
  72 *      get_options - Parse a string into a list of integers
  73 *      @str: String to be parsed
  74 *      @nints: size of integer array
  75 *      @ints: integer array
  76 *
  77 *      This function parses a string containing a comma-separated
  78 *      list of integers, a hyphen-separated range of _positive_ integers,
  79 *      or a combination of both.  The parse halts when the array is
  80 *      full, or when no more numbers can be retrieved from the
  81 *      string.
  82 *
  83 *      Return value is the character in the string which caused
  84 *      the parse to end (typically a null terminator, if @str is
  85 *      completely parseable).
  86 */
  87 
  88char *get_options(const char *str, int nints, int *ints)
  89{
  90        int res, i = 1;
  91
  92        while (i < nints) {
  93                res = get_option ((char **)&str, ints + i);
  94                if (res == 0)
  95                        break;
  96                if (res == 3) {
  97                        int range_nums;
  98                        range_nums = get_range((char **)&str, ints + i);
  99                        if (range_nums < 0)
 100                                break;
 101                        /*
 102                         * Decrement the result by one to leave out the
 103                         * last number in the range.  The next iteration
 104                         * will handle the upper number in the range
 105                         */
 106                        i += (range_nums - 1);
 107                }
 108                i++;
 109                if (res == 1)
 110                        break;
 111        }
 112        ints[0] = i - 1;
 113        return (char *)str;
 114}
 115
 116/**
 117 *      memparse - parse a string with mem suffixes into a number
 118 *      @ptr: Where parse begins
 119 *      @retptr: (output) Optional pointer to next char after parse completes
 120 *
 121 *      Parses a string into a number.  The number stored at @ptr is
 122 *      potentially suffixed with %K (for kilobytes, or 1024 bytes),
 123 *      %M (for megabytes, or 1048576 bytes), or %G (for gigabytes, or
 124 *      1073741824).  If the number is suffixed with K, M, or G, then
 125 *      the return value is the number multiplied by one kilobyte, one
 126 *      megabyte, or one gigabyte, respectively.
 127 */
 128
 129unsigned long long memparse(const char *ptr, char **retptr)
 130{
 131        char *endptr;   /* local pointer to end of parsed string */
 132
 133        unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
 134
 135        switch (*endptr) {
 136        case 'G':
 137        case 'g':
 138                ret <<= 10;
 139        case 'M':
 140        case 'm':
 141                ret <<= 10;
 142        case 'K':
 143        case 'k':
 144                ret <<= 10;
 145                endptr++;
 146        default:
 147                break;
 148        }
 149
 150        if (retptr)
 151                *retptr = endptr;
 152
 153        return ret;
 154}
 155
 156
 157EXPORT_SYMBOL(memparse);
 158EXPORT_SYMBOL(get_option);
 159EXPORT_SYMBOL(get_options);
 160
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