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#include <linux/ctype.h>
19
20/*
21 * If a hyphen was found in get_option, this will handle the
22 * range of numbers, M-N. This will expand the range and insert
23 * the values[M, M+1, ..., N] into the ints array in get_options.
24 */
25
26static int get_range(char **str, int *pint, int n)
27{
28 int x, inc_counter, upper_range;
29
30 (*str)++;
31 upper_range = simple_strtol((*str), NULL, 0);
32 inc_counter = upper_range - *pint;
33 for (x = *pint; n && x < upper_range; x++, n--)
34 *pint++ = x;
35 return inc_counter;
36}
37
38/**
39 * get_option - Parse integer from an option string
40 * @str: option string
41 * @pint: (output) integer value parsed from @str
42 *
43 * Read an int from an option string; if available accept a subsequent
44 * comma as well.
45 *
46 * Return values:
47 * 0 - no int in string
48 * 1 - int found, no subsequent comma
49 * 2 - int found including a subsequent comma
50 * 3 - hyphen found to denote a range
51 */
52
53int get_option(char **str, int *pint)
54{
55 char *cur = *str;
56
57 if (!cur || !(*cur))
58 return 0;
59 *pint = simple_strtol(cur, str, 0);
60 if (cur == *str)
61 return 0;
62 if (**str == ',') {
63 (*str)++;
64 return 2;
65 }
66 if (**str == '-')
67 return 3;
68
69 return 1;
70}
71EXPORT_SYMBOL(get_option);
72
73/**
74 * get_options - Parse a string into a list of integers
75 * @str: String to be parsed
76 * @nints: size of integer array
77 * @ints: integer array
78 *
79 * This function parses a string containing a comma-separated
80 * list of integers, a hyphen-separated range of _positive_ integers,
81 * or a combination of both. The parse halts when the array is
82 * full, or when no more numbers can be retrieved from the
83 * string.
84 *
85 * Return value is the character in the string which caused
86 * the parse to end (typically a null terminator, if @str is
87 * completely parseable).
88 */
89
90char *get_options(const char *str, int nints, int *ints)
91{
92 int res, i = 1;
93
94 while (i < nints) {
95 res = get_option((char **)&str, ints + i);
96 if (res == 0)
97 break;
98 if (res == 3) {
99 int range_nums;
100 range_nums = get_range((char **)&str, ints + i, nints - i);
101 if (range_nums < 0)
102 break;
103 /*
104 * Decrement the result by one to leave out the
105 * last number in the range. The next iteration
106 * will handle the upper number in the range
107 */
108 i += (range_nums - 1);
109 }
110 i++;
111 if (res == 1)
112 break;
113 }
114 ints[0] = i - 1;
115 return (char *)str;
116}
117EXPORT_SYMBOL(get_options);
118
119/**
120 * memparse - parse a string with mem suffixes into a number
121 * @ptr: Where parse begins
122 * @retptr: (output) Optional pointer to next char after parse completes
123 *
124 * Parses a string into a number. The number stored at @ptr is
125 * potentially suffixed with K, M, G, T, P, E.
126 */
127
128unsigned long long memparse(const char *ptr, char **retptr)
129{
130 char *endptr; /* local pointer to end of parsed string */
131
132 unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
133
134 switch (*endptr) {
135 case 'E':
136 case 'e':
137 ret <<= 10;
138 case 'P':
139 case 'p':
140 ret <<= 10;
141 case 'T':
142 case 't':
143 ret <<= 10;
144 case 'G':
145 case 'g':
146 ret <<= 10;
147 case 'M':
148 case 'm':
149 ret <<= 10;
150 case 'K':
151 case 'k':
152 ret <<= 10;
153 endptr++;
154 default:
155 break;
156 }
157
158 if (retptr)
159 *retptr = endptr;
160
161 return ret;
162}
163EXPORT_SYMBOL(memparse);
164
165/**
166 * parse_option_str - Parse a string and check an option is set or not
167 * @str: String to be parsed
168 * @option: option name
169 *
170 * This function parses a string containing a comma-separated list of
171 * strings like a=b,c.
172 *
173 * Return true if there's such option in the string, or return false.
174 */
175bool parse_option_str(const char *str, const char *option)
176{
177 while (*str) {
178 if (!strncmp(str, option, strlen(option))) {
179 str += strlen(option);
180 if (!*str || *str == ',')
181 return true;
182 }
183
184 while (*str && *str != ',')
185 str++;
186
187 if (*str == ',')
188 str++;
189 }
190
191 return false;
192}
193
194/*
195 * Parse a string to get a param value pair.
196 * You can use " around spaces, but can't escape ".
197 * Hyphens and underscores equivalent in parameter names.
198 */
199char *next_arg(char *args, char **param, char **val)
200{
201 unsigned int i, equals = 0;
202 int in_quote = 0, quoted = 0;
203 char *next;
204
205 if (*args == '"') {
206 args++;
207 in_quote = 1;
208 quoted = 1;
209 }
210
211 for (i = 0; args[i]; i++) {
212 if (isspace(args[i]) && !in_quote)
213 break;
214 if (equals == 0) {
215 if (args[i] == '=')
216 equals = i;
217 }
218 if (args[i] == '"')
219 in_quote = !in_quote;
220 }
221
222 *param = args;
223 if (!equals)
224 *val = NULL;
225 else {
226 args[equals] = '\0';
227 *val = args + equals + 1;
228
229 /* Don't include quotes in value. */
230 if (**val == '"') {
231 (*val)++;
232 if (args[i-1] == '"')
233 args[i-1] = '\0';
234 }
235 }
236 if (quoted && args[i-1] == '"')
237 args[i-1] = '\0';
238
239 if (args[i]) {
240 args[i] = '\0';
241 next = args + i + 1;
242 } else
243 next = args + i;
244
245 /* Chew up trailing spaces. */
246 return skip_spaces(next);
247}
248