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/export.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
get_range(char ** str,int * pint,int n)25 static int get_range(char **str, int *pint, int n)
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; n && x < upper_range; x++, n--)
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
get_option(char ** str,int * pint)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 EXPORT_SYMBOL(get_option);
71
72 /**
73 * get_options - Parse a string into a list of integers
74 * @str: String to be parsed
75 * @nints: size of integer array
76 * @ints: integer array
77 *
78 * This function parses a string containing a comma-separated
79 * list of integers, a hyphen-separated range of _positive_ integers,
80 * or a combination of both. The parse halts when the array is
81 * full, or when no more numbers can be retrieved from the
82 * string.
83 *
84 * Return value is the character in the string which caused
85 * the parse to end (typically a null terminator, if @str is
86 * completely parseable).
87 */
88
get_options(const char * str,int nints,int * ints)89 char *get_options(const char *str, int nints, int *ints)
90 {
91 int res, i = 1;
92
93 while (i < nints) {
94 res = get_option((char **)&str, ints + i);
95 if (res == 0)
96 break;
97 if (res == 3) {
98 int range_nums;
99 range_nums = get_range((char **)&str, ints + i, nints - i);
100 if (range_nums < 0)
101 break;
102 /*
103 * Decrement the result by one to leave out the
104 * last number in the range. The next iteration
105 * will handle the upper number in the range
106 */
107 i += (range_nums - 1);
108 }
109 i++;
110 if (res == 1)
111 break;
112 }
113 ints[0] = i - 1;
114 return (char *)str;
115 }
116 EXPORT_SYMBOL(get_options);
117
118 /**
119 * memparse - parse a string with mem suffixes into a number
120 * @ptr: Where parse begins
121 * @retptr: (output) Optional pointer to next char after parse completes
122 *
123 * Parses a string into a number. The number stored at @ptr is
124 * potentially suffixed with K, M, G, T, P, E.
125 */
126
memparse(const char * ptr,char ** retptr)127 unsigned long long memparse(const char *ptr, char **retptr)
128 {
129 char *endptr; /* local pointer to end of parsed string */
130
131 unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
132
133 switch (*endptr) {
134 case 'E':
135 case 'e':
136 ret <<= 10;
137 case 'P':
138 case 'p':
139 ret <<= 10;
140 case 'T':
141 case 't':
142 ret <<= 10;
143 case 'G':
144 case 'g':
145 ret <<= 10;
146 case 'M':
147 case 'm':
148 ret <<= 10;
149 case 'K':
150 case 'k':
151 ret <<= 10;
152 endptr++;
153 default:
154 break;
155 }
156
157 if (retptr)
158 *retptr = endptr;
159
160 return ret;
161 }
162 EXPORT_SYMBOL(memparse);
163
164 /**
165 * parse_option_str - Parse a string and check an option is set or not
166 * @str: String to be parsed
167 * @option: option name
168 *
169 * This function parses a string containing a comma-separated list of
170 * strings like a=b,c.
171 *
172 * Return true if there's such option in the string, or return false.
173 */
parse_option_str(const char * str,const char * option)174 bool parse_option_str(const char *str, const char *option)
175 {
176 while (*str) {
177 if (!strncmp(str, option, strlen(option))) {
178 str += strlen(option);
179 if (!*str || *str == ',')
180 return true;
181 }
182
183 while (*str && *str != ',')
184 str++;
185
186 if (*str == ',')
187 str++;
188 }
189
190 return false;
191 }
192