1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/lib/cmdline.c |
4 | * Helper functions generally used for parsing kernel command line |
5 | * and module options. |
6 | * |
7 | * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c. |
8 | * |
9 | * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs |
10 | */ |
11 | |
12 | #include <linux/export.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/string.h> |
15 | #include <linux/ctype.h> |
16 | |
17 | /* |
18 | * If a hyphen was found in get_option, this will handle the |
19 | * range of numbers, M-N. This will expand the range and insert |
20 | * the values[M, M+1, ..., N] into the ints array in get_options. |
21 | */ |
22 | |
23 | static int get_range(char **str, int *pint, int n) |
24 | { |
25 | int x, inc_counter, upper_range; |
26 | |
27 | (*str)++; |
28 | upper_range = simple_strtol((*str), NULL, 0); |
29 | inc_counter = upper_range - *pint; |
30 | for (x = *pint; n && x < upper_range; x++, n--) |
31 | *pint++ = x; |
32 | return inc_counter; |
33 | } |
34 | |
35 | /** |
36 | * get_option - Parse integer from an option string |
37 | * @str: option string |
38 | * @pint: (optional output) integer value parsed from @str |
39 | * |
40 | * Read an int from an option string; if available accept a subsequent |
41 | * comma as well. |
42 | * |
43 | * When @pint is NULL the function can be used as a validator of |
44 | * the current option in the string. |
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 | * Leading hyphen without integer is no integer case, but we consume it |
53 | * for the sake of simplification. |
54 | */ |
55 | |
56 | int get_option(char **str, int *pint) |
57 | { |
58 | char *cur = *str; |
59 | int value; |
60 | |
61 | if (!cur || !(*cur)) |
62 | return 0; |
63 | if (*cur == '-') |
64 | value = -simple_strtoull(++cur, str, 0); |
65 | else |
66 | value = simple_strtoull(cur, str, 0); |
67 | if (pint) |
68 | *pint = value; |
69 | if (cur == *str) |
70 | return 0; |
71 | if (**str == ',') { |
72 | (*str)++; |
73 | return 2; |
74 | } |
75 | if (**str == '-') |
76 | return 3; |
77 | |
78 | return 1; |
79 | } |
80 | EXPORT_SYMBOL(get_option); |
81 | |
82 | /** |
83 | * get_options - Parse a string into a list of integers |
84 | * @str: String to be parsed |
85 | * @nints: size of integer array |
86 | * @ints: integer array (must have room for at least one element) |
87 | * |
88 | * This function parses a string containing a comma-separated |
89 | * list of integers, a hyphen-separated range of _positive_ integers, |
90 | * or a combination of both. The parse halts when the array is |
91 | * full, or when no more numbers can be retrieved from the |
92 | * string. |
93 | * |
94 | * When @nints is 0, the function just validates the given @str and |
95 | * returns the amount of parseable integers as described below. |
96 | * |
97 | * Returns: |
98 | * |
99 | * The first element is filled by the number of collected integers |
100 | * in the range. The rest is what was parsed from the @str. |
101 | * |
102 | * Return value is the character in the string which caused |
103 | * the parse to end (typically a null terminator, if @str is |
104 | * completely parseable). |
105 | */ |
106 | |
107 | char *get_options(const char *str, int nints, int *ints) |
108 | { |
109 | bool validate = (nints == 0); |
110 | int res, i = 1; |
111 | |
112 | while (i < nints || validate) { |
113 | int *pint = validate ? ints : ints + i; |
114 | |
115 | res = get_option(str: (char **)&str, pint); |
116 | if (res == 0) |
117 | break; |
118 | if (res == 3) { |
119 | int n = validate ? 0 : nints - i; |
120 | int range_nums; |
121 | |
122 | range_nums = get_range(str: (char **)&str, pint, n); |
123 | if (range_nums < 0) |
124 | break; |
125 | /* |
126 | * Decrement the result by one to leave out the |
127 | * last number in the range. The next iteration |
128 | * will handle the upper number in the range |
129 | */ |
130 | i += (range_nums - 1); |
131 | } |
132 | i++; |
133 | if (res == 1) |
134 | break; |
135 | } |
136 | ints[0] = i - 1; |
137 | return (char *)str; |
138 | } |
139 | EXPORT_SYMBOL(get_options); |
140 | |
141 | /** |
142 | * memparse - parse a string with mem suffixes into a number |
143 | * @ptr: Where parse begins |
144 | * @retptr: (output) Optional pointer to next char after parse completes |
145 | * |
146 | * Parses a string into a number. The number stored at @ptr is |
147 | * potentially suffixed with K, M, G, T, P, E. |
148 | */ |
149 | |
150 | unsigned long long memparse(const char *ptr, char **retptr) |
151 | { |
152 | char *endptr; /* local pointer to end of parsed string */ |
153 | |
154 | unsigned long long ret = simple_strtoull(ptr, &endptr, 0); |
155 | |
156 | switch (*endptr) { |
157 | case 'E': |
158 | case 'e': |
159 | ret <<= 10; |
160 | fallthrough; |
161 | case 'P': |
162 | case 'p': |
163 | ret <<= 10; |
164 | fallthrough; |
165 | case 'T': |
166 | case 't': |
167 | ret <<= 10; |
168 | fallthrough; |
169 | case 'G': |
170 | case 'g': |
171 | ret <<= 10; |
172 | fallthrough; |
173 | case 'M': |
174 | case 'm': |
175 | ret <<= 10; |
176 | fallthrough; |
177 | case 'K': |
178 | case 'k': |
179 | ret <<= 10; |
180 | endptr++; |
181 | fallthrough; |
182 | default: |
183 | break; |
184 | } |
185 | |
186 | if (retptr) |
187 | *retptr = endptr; |
188 | |
189 | return ret; |
190 | } |
191 | EXPORT_SYMBOL(memparse); |
192 | |
193 | /** |
194 | * parse_option_str - Parse a string and check an option is set or not |
195 | * @str: String to be parsed |
196 | * @option: option name |
197 | * |
198 | * This function parses a string containing a comma-separated list of |
199 | * strings like a=b,c. |
200 | * |
201 | * Return true if there's such option in the string, or return false. |
202 | */ |
203 | bool parse_option_str(const char *str, const char *option) |
204 | { |
205 | while (*str) { |
206 | if (!strncmp(str, option, strlen(option))) { |
207 | str += strlen(option); |
208 | if (!*str || *str == ',') |
209 | return true; |
210 | } |
211 | |
212 | while (*str && *str != ',') |
213 | str++; |
214 | |
215 | if (*str == ',') |
216 | str++; |
217 | } |
218 | |
219 | return false; |
220 | } |
221 | |
222 | /* |
223 | * Parse a string to get a param value pair. |
224 | * You can use " around spaces, but can't escape ". |
225 | * Hyphens and underscores equivalent in parameter names. |
226 | */ |
227 | char *next_arg(char *args, char **param, char **val) |
228 | { |
229 | unsigned int i, equals = 0; |
230 | int in_quote = 0, quoted = 0; |
231 | |
232 | if (*args == '"') { |
233 | args++; |
234 | in_quote = 1; |
235 | quoted = 1; |
236 | } |
237 | |
238 | for (i = 0; args[i]; i++) { |
239 | if (isspace(args[i]) && !in_quote) |
240 | break; |
241 | if (equals == 0) { |
242 | if (args[i] == '=') |
243 | equals = i; |
244 | } |
245 | if (args[i] == '"') |
246 | in_quote = !in_quote; |
247 | } |
248 | |
249 | *param = args; |
250 | if (!equals) |
251 | *val = NULL; |
252 | else { |
253 | args[equals] = '\0'; |
254 | *val = args + equals + 1; |
255 | |
256 | /* Don't include quotes in value. */ |
257 | if (**val == '"') { |
258 | (*val)++; |
259 | if (args[i-1] == '"') |
260 | args[i-1] = '\0'; |
261 | } |
262 | } |
263 | if (quoted && i > 0 && args[i-1] == '"') |
264 | args[i-1] = '\0'; |
265 | |
266 | if (args[i]) { |
267 | args[i] = '\0'; |
268 | args += i + 1; |
269 | } else |
270 | args += i; |
271 | |
272 | /* Chew up trailing spaces. */ |
273 | return skip_spaces(args); |
274 | } |
275 | EXPORT_SYMBOL(next_arg); |
276 | |