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: (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 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 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 */ 124 125 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 fallthrough; 136 case 'P': 137 case 'p': 138 ret <<= 10; 139 fallthrough; 140 case 'T': 141 case 't': 142 ret <<= 10; 143 fallthrough; 144 case 'G': 145 case 'g': 146 ret <<= 10; 147 fallthrough; 148 case 'M': 149 case 'm': 150 ret <<= 10; 151 fallthrough; 152 case 'K': 153 case 'k': 154 ret <<= 10; 155 endptr++; 156 fallthrough; 157 default: 158 break; 159 } 160 161 if (retptr) 162 *retptr = endptr; 163 164 return ret; 165 } 166 EXPORT_SYMBOL(memparse); 167 168 /** 169 * parse_option_str - Parse a string and check an option is set or not 170 * @str: String to be parsed 171 * @option: option name 172 * 173 * This function parses a string containing a comma-separated list of 174 * strings like a=b,c. 175 * 176 * Return true if there's such option in the string, or return false. 177 */ 178 bool parse_option_str(const char *str, const char *option) 179 { 180 while (*str) { 181 if (!strncmp(str, option, strlen(option))) { 182 str += strlen(option); 183 if (!*str || *str == ',') 184 return true; 185 } 186 187 while (*str && *str != ',') 188 str++; 189 190 if (*str == ',') 191 str++; 192 } 193 194 return false; 195 } 196 197 /* 198 * Parse a string to get a param value pair. 199 * You can use " around spaces, but can't escape ". 200 * Hyphens and underscores equivalent in parameter names. 201 */ 202 char *next_arg(char *args, char **param, char **val) 203 { 204 unsigned int i, equals = 0; 205 int in_quote = 0, quoted = 0; 206 char *next; 207 208 if (*args == '"') { 209 args++; 210 in_quote = 1; 211 quoted = 1; 212 } 213 214 for (i = 0; args[i]; i++) { 215 if (isspace(args[i]) && !in_quote) 216 break; 217 if (equals == 0) { 218 if (args[i] == '=') 219 equals = i; 220 } 221 if (args[i] == '"') 222 in_quote = !in_quote; 223 } 224 225 *param = args; 226 if (!equals) 227 *val = NULL; 228 else { 229 args[equals] = '\0'; 230 *val = args + equals + 1; 231 232 /* Don't include quotes in value. */ 233 if (**val == '"') { 234 (*val)++; 235 if (args[i-1] == '"') 236 args[i-1] = '\0'; 237 } 238 } 239 if (quoted && args[i-1] == '"') 240 args[i-1] = '\0'; 241 242 if (args[i]) { 243 args[i] = '\0'; 244 next = args + i + 1; 245 } else 246 next = args + i; 247 248 /* Chew up trailing spaces. */ 249 return skip_spaces(next); 250 } 251