1 /* 2 * linux/lib/cmdline.c 3 * Helper functions generally used for parsing kernel command line 4 * and module options. 5 * 6 * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c. 7 * 8 * This source code is licensed under the GNU General Public License, 9 * Version 2. See the file COPYING for more details. 10 * 11 * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs 12 * 13 */ 14 15 #include <linux/export.h> 16 #include <linux/kernel.h> 17 #include <linux/string.h> 18 #include <linux/ctype.h> 19 20 /* 21 * If a hyphen was found in get_option, this will handle the 22 * range of numbers, M-N. This will expand the range and insert 23 * the values[M, M+1, ..., N] into the ints array in get_options. 24 */ 25 26 static int get_range(char **str, int *pint, int n) 27 { 28 int x, inc_counter, upper_range; 29 30 (*str)++; 31 upper_range = simple_strtol((*str), NULL, 0); 32 inc_counter = upper_range - *pint; 33 for (x = *pint; n && x < upper_range; x++, n--) 34 *pint++ = x; 35 return inc_counter; 36 } 37 38 /** 39 * get_option - Parse integer from an option string 40 * @str: option string 41 * @pint: (output) integer value parsed from @str 42 * 43 * Read an int from an option string; if available accept a subsequent 44 * comma as well. 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 53 int get_option(char **str, int *pint) 54 { 55 char *cur = *str; 56 57 if (!cur || !(*cur)) 58 return 0; 59 *pint = simple_strtol(cur, str, 0); 60 if (cur == *str) 61 return 0; 62 if (**str == ',') { 63 (*str)++; 64 return 2; 65 } 66 if (**str == '-') 67 return 3; 68 69 return 1; 70 } 71 EXPORT_SYMBOL(get_option); 72 73 /** 74 * get_options - Parse a string into a list of integers 75 * @str: String to be parsed 76 * @nints: size of integer array 77 * @ints: integer array 78 * 79 * This function parses a string containing a comma-separated 80 * list of integers, a hyphen-separated range of _positive_ integers, 81 * or a combination of both. The parse halts when the array is 82 * full, or when no more numbers can be retrieved from the 83 * string. 84 * 85 * Return value is the character in the string which caused 86 * the parse to end (typically a null terminator, if @str is 87 * completely parseable). 88 */ 89 90 char *get_options(const char *str, int nints, int *ints) 91 { 92 int res, i = 1; 93 94 while (i < nints) { 95 res = get_option((char **)&str, ints + i); 96 if (res == 0) 97 break; 98 if (res == 3) { 99 int range_nums; 100 range_nums = get_range((char **)&str, ints + i, nints - i); 101 if (range_nums < 0) 102 break; 103 /* 104 * Decrement the result by one to leave out the 105 * last number in the range. The next iteration 106 * will handle the upper number in the range 107 */ 108 i += (range_nums - 1); 109 } 110 i++; 111 if (res == 1) 112 break; 113 } 114 ints[0] = i - 1; 115 return (char *)str; 116 } 117 EXPORT_SYMBOL(get_options); 118 119 /** 120 * memparse - parse a string with mem suffixes into a number 121 * @ptr: Where parse begins 122 * @retptr: (output) Optional pointer to next char after parse completes 123 * 124 * Parses a string into a number. The number stored at @ptr is 125 * potentially suffixed with K, M, G, T, P, E. 126 */ 127 128 unsigned long long memparse(const char *ptr, char **retptr) 129 { 130 char *endptr; /* local pointer to end of parsed string */ 131 132 unsigned long long ret = simple_strtoull(ptr, &endptr, 0); 133 134 switch (*endptr) { 135 case 'E': 136 case 'e': 137 ret <<= 10; 138 case 'P': 139 case 'p': 140 ret <<= 10; 141 case 'T': 142 case 't': 143 ret <<= 10; 144 case 'G': 145 case 'g': 146 ret <<= 10; 147 case 'M': 148 case 'm': 149 ret <<= 10; 150 case 'K': 151 case 'k': 152 ret <<= 10; 153 endptr++; 154 default: 155 break; 156 } 157 158 if (retptr) 159 *retptr = endptr; 160 161 return ret; 162 } 163 EXPORT_SYMBOL(memparse); 164 165 /** 166 * parse_option_str - Parse a string and check an option is set or not 167 * @str: String to be parsed 168 * @option: option name 169 * 170 * This function parses a string containing a comma-separated list of 171 * strings like a=b,c. 172 * 173 * Return true if there's such option in the string, or return false. 174 */ 175 bool parse_option_str(const char *str, const char *option) 176 { 177 while (*str) { 178 if (!strncmp(str, option, strlen(option))) { 179 str += strlen(option); 180 if (!*str || *str == ',') 181 return true; 182 } 183 184 while (*str && *str != ',') 185 str++; 186 187 if (*str == ',') 188 str++; 189 } 190 191 return false; 192 } 193 194 /* 195 * Parse a string to get a param value pair. 196 * You can use " around spaces, but can't escape ". 197 * Hyphens and underscores equivalent in parameter names. 198 */ 199 char *next_arg(char *args, char **param, char **val) 200 { 201 unsigned int i, equals = 0; 202 int in_quote = 0, quoted = 0; 203 char *next; 204 205 if (*args == '"') { 206 args++; 207 in_quote = 1; 208 quoted = 1; 209 } 210 211 for (i = 0; args[i]; i++) { 212 if (isspace(args[i]) && !in_quote) 213 break; 214 if (equals == 0) { 215 if (args[i] == '=') 216 equals = i; 217 } 218 if (args[i] == '"') 219 in_quote = !in_quote; 220 } 221 222 *param = args; 223 if (!equals) 224 *val = NULL; 225 else { 226 args[equals] = '\0'; 227 *val = args + equals + 1; 228 229 /* Don't include quotes in value. */ 230 if (**val == '"') { 231 (*val)++; 232 if (args[i-1] == '"') 233 args[i-1] = '\0'; 234 } 235 } 236 if (quoted && args[i-1] == '"') 237 args[i-1] = '\0'; 238 239 if (args[i]) { 240 args[i] = '\0'; 241 next = args + i + 1; 242 } else 243 next = args + i; 244 245 /* Chew up trailing spaces. */ 246 return skip_spaces(next); 247 } 248