Root/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 * 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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