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
get_range(char ** str,int * pint,int n)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: (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 * Return values:
44 * 0 - no int in string
45 * 1 - int found, no subsequent comma
46 * 2 - int found including a subsequent comma
47 * 3 - hyphen found to denote a range
48 */
49
get_option(char ** str,int * pint)50 int get_option(char **str, int *pint)
51 {
52 char *cur = *str;
53
54 if (!cur || !(*cur))
55 return 0;
56 *pint = simple_strtol(cur, str, 0);
57 if (cur == *str)
58 return 0;
59 if (**str == ',') {
60 (*str)++;
61 return 2;
62 }
63 if (**str == '-')
64 return 3;
65
66 return 1;
67 }
68 EXPORT_SYMBOL(get_option);
69
70 /**
71 * get_options - Parse a string into a list of integers
72 * @str: String to be parsed
73 * @nints: size of integer array
74 * @ints: integer array
75 *
76 * This function parses a string containing a comma-separated
77 * list of integers, a hyphen-separated range of _positive_ integers,
78 * or a combination of both. The parse halts when the array is
79 * full, or when no more numbers can be retrieved from the
80 * string.
81 *
82 * Return value is the character in the string which caused
83 * the parse to end (typically a null terminator, if @str is
84 * completely parseable).
85 */
86
get_options(const char * str,int nints,int * ints)87 char *get_options(const char *str, int nints, int *ints)
88 {
89 int res, i = 1;
90
91 while (i < nints) {
92 res = get_option((char **)&str, ints + i);
93 if (res == 0)
94 break;
95 if (res == 3) {
96 int range_nums;
97 range_nums = get_range((char **)&str, ints + i, nints - i);
98 if (range_nums < 0)
99 break;
100 /*
101 * Decrement the result by one to leave out the
102 * last number in the range. The next iteration
103 * will handle the upper number in the range
104 */
105 i += (range_nums - 1);
106 }
107 i++;
108 if (res == 1)
109 break;
110 }
111 ints[0] = i - 1;
112 return (char *)str;
113 }
114 EXPORT_SYMBOL(get_options);
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, M, G, T, P, E.
123 */
124
memparse(const char * ptr,char ** retptr)125 unsigned long long memparse(const char *ptr, char **retptr)
126 {
127 char *endptr; /* local pointer to end of parsed string */
128
129 unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
130
131 switch (*endptr) {
132 case 'E':
133 case 'e':
134 ret <<= 10;
135 /* fall through */
136 case 'P':
137 case 'p':
138 ret <<= 10;
139 /* fall through */
140 case 'T':
141 case 't':
142 ret <<= 10;
143 /* fall through */
144 case 'G':
145 case 'g':
146 ret <<= 10;
147 /* fall through */
148 case 'M':
149 case 'm':
150 ret <<= 10;
151 /* fall through */
152 case 'K':
153 case 'k':
154 ret <<= 10;
155 endptr++;
156 default:
157 break;
158 }
159
160 if (retptr)
161 *retptr = endptr;
162
163 return ret;
164 }
165 EXPORT_SYMBOL(memparse);
166
167 /**
168 * parse_option_str - Parse a string and check an option is set or not
169 * @str: String to be parsed
170 * @option: option name
171 *
172 * This function parses a string containing a comma-separated list of
173 * strings like a=b,c.
174 *
175 * Return true if there's such option in the string, or return false.
176 */
parse_option_str(const char * str,const char * option)177 bool parse_option_str(const char *str, const char *option)
178 {
179 while (*str) {
180 if (!strncmp(str, option, strlen(option))) {
181 str += strlen(option);
182 if (!*str || *str == ',')
183 return true;
184 }
185
186 while (*str && *str != ',')
187 str++;
188
189 if (*str == ',')
190 str++;
191 }
192
193 return false;
194 }
195
196 /*
197 * Parse a string to get a param value pair.
198 * You can use " around spaces, but can't escape ".
199 * Hyphens and underscores equivalent in parameter names.
200 */
next_arg(char * args,char ** param,char ** val)201 char *next_arg(char *args, char **param, char **val)
202 {
203 unsigned int i, equals = 0;
204 int in_quote = 0, quoted = 0;
205 char *next;
206
207 if (*args == '"') {
208 args++;
209 in_quote = 1;
210 quoted = 1;
211 }
212
213 for (i = 0; args[i]; i++) {
214 if (isspace(args[i]) && !in_quote)
215 break;
216 if (equals == 0) {
217 if (args[i] == '=')
218 equals = i;
219 }
220 if (args[i] == '"')
221 in_quote = !in_quote;
222 }
223
224 *param = args;
225 if (!equals)
226 *val = NULL;
227 else {
228 args[equals] = '\0';
229 *val = args + equals + 1;
230
231 /* Don't include quotes in value. */
232 if (**val == '"') {
233 (*val)++;
234 if (args[i-1] == '"')
235 args[i-1] = '\0';
236 }
237 }
238 if (quoted && args[i-1] == '"')
239 args[i-1] = '\0';
240
241 if (args[i]) {
242 args[i] = '\0';
243 next = args + i + 1;
244 } else
245 next = args + i;
246
247 /* Chew up trailing spaces. */
248 return skip_spaces(next);
249 }
250