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 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 * Return value is the character in the string which caused 95 * the parse to end (typically a null terminator, if @str is 96 * completely parseable). 97 */ 98 99 char *get_options(const char *str, int nints, int *ints) 100 { 101 int res, i = 1; 102 103 while (i < nints) { 104 res = get_option((char **)&str, ints + i); 105 if (res == 0) 106 break; 107 if (res == 3) { 108 int range_nums; 109 range_nums = get_range((char **)&str, ints + i, nints - i); 110 if (range_nums < 0) 111 break; 112 /* 113 * Decrement the result by one to leave out the 114 * last number in the range. The next iteration 115 * will handle the upper number in the range 116 */ 117 i += (range_nums - 1); 118 } 119 i++; 120 if (res == 1) 121 break; 122 } 123 ints[0] = i - 1; 124 return (char *)str; 125 } 126 EXPORT_SYMBOL(get_options); 127 128 /** 129 * memparse - parse a string with mem suffixes into a number 130 * @ptr: Where parse begins 131 * @retptr: (output) Optional pointer to next char after parse completes 132 * 133 * Parses a string into a number. The number stored at @ptr is 134 * potentially suffixed with K, M, G, T, P, E. 135 */ 136 137 unsigned long long memparse(const char *ptr, char **retptr) 138 { 139 char *endptr; /* local pointer to end of parsed string */ 140 141 unsigned long long ret = simple_strtoull(ptr, &endptr, 0); 142 143 switch (*endptr) { 144 case 'E': 145 case 'e': 146 ret <<= 10; 147 fallthrough; 148 case 'P': 149 case 'p': 150 ret <<= 10; 151 fallthrough; 152 case 'T': 153 case 't': 154 ret <<= 10; 155 fallthrough; 156 case 'G': 157 case 'g': 158 ret <<= 10; 159 fallthrough; 160 case 'M': 161 case 'm': 162 ret <<= 10; 163 fallthrough; 164 case 'K': 165 case 'k': 166 ret <<= 10; 167 endptr++; 168 fallthrough; 169 default: 170 break; 171 } 172 173 if (retptr) 174 *retptr = endptr; 175 176 return ret; 177 } 178 EXPORT_SYMBOL(memparse); 179 180 /** 181 * parse_option_str - Parse a string and check an option is set or not 182 * @str: String to be parsed 183 * @option: option name 184 * 185 * This function parses a string containing a comma-separated list of 186 * strings like a=b,c. 187 * 188 * Return true if there's such option in the string, or return false. 189 */ 190 bool parse_option_str(const char *str, const char *option) 191 { 192 while (*str) { 193 if (!strncmp(str, option, strlen(option))) { 194 str += strlen(option); 195 if (!*str || *str == ',') 196 return true; 197 } 198 199 while (*str && *str != ',') 200 str++; 201 202 if (*str == ',') 203 str++; 204 } 205 206 return false; 207 } 208 209 /* 210 * Parse a string to get a param value pair. 211 * You can use " around spaces, but can't escape ". 212 * Hyphens and underscores equivalent in parameter names. 213 */ 214 char *next_arg(char *args, char **param, char **val) 215 { 216 unsigned int i, equals = 0; 217 int in_quote = 0, quoted = 0; 218 char *next; 219 220 if (*args == '"') { 221 args++; 222 in_quote = 1; 223 quoted = 1; 224 } 225 226 for (i = 0; args[i]; i++) { 227 if (isspace(args[i]) && !in_quote) 228 break; 229 if (equals == 0) { 230 if (args[i] == '=') 231 equals = i; 232 } 233 if (args[i] == '"') 234 in_quote = !in_quote; 235 } 236 237 *param = args; 238 if (!equals) 239 *val = NULL; 240 else { 241 args[equals] = '\0'; 242 *val = args + equals + 1; 243 244 /* Don't include quotes in value. */ 245 if (**val == '"') { 246 (*val)++; 247 if (args[i-1] == '"') 248 args[i-1] = '\0'; 249 } 250 } 251 if (quoted && args[i-1] == '"') 252 args[i-1] = '\0'; 253 254 if (args[i]) { 255 args[i] = '\0'; 256 next = args + i + 1; 257 } else 258 next = args + i; 259 260 /* Chew up trailing spaces. */ 261 return skip_spaces(next); 262 } 263