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: 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((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((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 * Return: The value as recognized by simple_strtoull() multiplied 150 * by the value as specified by suffix, if any. 151 */ 152 153 unsigned long long memparse(const char *ptr, char **retptr) 154 { 155 char *endptr; /* local pointer to end of parsed string */ 156 unsigned long long ret = simple_strtoull(ptr, &endptr, 0); 157 unsigned int shl = 0; 158 159 /* Consume valid suffix even in case of overflow. */ 160 switch (*endptr) { 161 case 'E': 162 case 'e': 163 shl += 10; 164 fallthrough; 165 case 'P': 166 case 'p': 167 shl += 10; 168 fallthrough; 169 case 'T': 170 case 't': 171 shl += 10; 172 fallthrough; 173 case 'G': 174 case 'g': 175 shl += 10; 176 fallthrough; 177 case 'M': 178 case 'm': 179 shl += 10; 180 fallthrough; 181 case 'K': 182 case 'k': 183 shl += 10; 184 fallthrough; 185 default: 186 break; 187 } 188 189 if (shl && likely(ptr != endptr)) { 190 /* Have valid suffix with preceding number. */ 191 if (unlikely(check_shl_overflow(ret, shl, &ret))) 192 ret = ULLONG_MAX; 193 endptr++; 194 } 195 196 if (retptr) 197 *retptr = endptr; 198 199 return ret; 200 } 201 EXPORT_SYMBOL(memparse); 202 203 /** 204 * parse_option_str - Parse a string and check an option is set or not 205 * @str: String to be parsed 206 * @option: option name 207 * 208 * This function parses a string containing a comma-separated list of 209 * strings like a=b,c. 210 * 211 * Return: True if there's such option in the string or false otherwise. 212 */ 213 bool parse_option_str(const char *str, const char *option) 214 { 215 while (*str) { 216 if (!strncmp(str, option, strlen(option))) { 217 str += strlen(option); 218 if (!*str || *str == ',') 219 return true; 220 } 221 222 while (*str && *str != ',') 223 str++; 224 225 if (*str == ',') 226 str++; 227 } 228 229 return false; 230 } 231 232 /* 233 * Parse a string to get a param value pair. 234 * You can use " around spaces, but can't escape ". 235 * Hyphens and underscores equivalent in parameter names. 236 */ 237 char *next_arg(char *args, char **param, char **val) 238 { 239 unsigned int i, equals = 0; 240 int in_quote = 0, quoted = 0; 241 242 if (*args == '"') { 243 args++; 244 in_quote = 1; 245 quoted = 1; 246 } 247 248 for (i = 0; args[i]; i++) { 249 if (isspace(args[i]) && !in_quote) 250 break; 251 if (equals == 0) { 252 if (args[i] == '=') 253 equals = i; 254 } 255 if (args[i] == '"') 256 in_quote = !in_quote; 257 } 258 259 *param = args; 260 if (!equals) 261 *val = NULL; 262 else { 263 args[equals] = '\0'; 264 *val = args + equals + 1; 265 266 /* Don't include quotes in value. */ 267 if (**val == '"') { 268 (*val)++; 269 if (args[i-1] == '"') 270 args[i-1] = '\0'; 271 } 272 } 273 if (quoted && i > 0 && args[i-1] == '"') 274 args[i-1] = '\0'; 275 276 if (args[i]) { 277 args[i] = '\0'; 278 args += i + 1; 279 } else 280 args += i; 281 282 /* Chew up trailing spaces. */ 283 return skip_spaces(args); 284 } 285 EXPORT_SYMBOL(next_arg); 286