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  *      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 
 25 static 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 
 52 int 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  
 88 char *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 
129 unsigned 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 
157 EXPORT_SYMBOL(memparse);
158 EXPORT_SYMBOL(get_option);
159 EXPORT_SYMBOL(get_options);
160
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Linux/lib/cmdline.c
