the-tree/lib/cmdline.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * linux/lib/cmdline.c
0004  * Helper functions generally used for parsing kernel command line
0005  * and module options.
0006  *
0007  * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
0008  *
0009  * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
0010  */
0011
0012 #include <linux/export.h>
0013 #include <linux/kernel.h>
0014 #include <linux/string.h>
0015 #include <linux/ctype.h>
0016
0017 /*
0018  *  If a hyphen was found in get_option, this will handle the
0019  *  range of numbers, M-N.  This will expand the range and insert
0020  *  the values[M, M+1, ..., N] into the ints array in get_options.
0021  */
0022
0023 static int get_range(char **str, int *pint, int n)
0024 {
0025     int x, inc_counter, upper_range;
0026
0027     (*str)++;
0028     upper_range = simple_strtol((*str), NULL, 0);
0029     inc_counter = upper_range - *pint;
0030     for (x = *pint; n && x < upper_range; x++, n--)
0031         *pint++ = x;
0032     return inc_counter;
0033 }
0034
0035 /**
0036  *  get_option - Parse integer from an option string
0037  *  @str: option string
0038  *  @pint: (optional output) integer value parsed from @str
0039  *
0040  *  Read an int from an option string; if available accept a subsequent
0041  *  comma as well.
0042  *
0043  *  When @pint is NULL the function can be used as a validator of
0044  *  the current option in the string.
0045  *
0046  *  Return values:
0047  *  0 - no int in string
0048  *  1 - int found, no subsequent comma
0049  *  2 - int found including a subsequent comma
0050  *  3 - hyphen found to denote a range
0051  *
0052  *  Leading hyphen without integer is no integer case, but we consume it
0053  *  for the sake of simplification.
0054  */
0055
0056 int get_option(char **str, int *pint)
0057 {
0058     char *cur = *str;
0059     int value;
0060
0061     if (!cur || !(*cur))
0062         return 0;
0063     if (*cur == '-')
0064         value = -simple_strtoull(++cur, str, 0);
0065     else
0066         value = simple_strtoull(cur, str, 0);
0067     if (pint)
0068         *pint = value;
0069     if (cur == *str)
0070         return 0;
0071     if (**str == ',') {
0072         (*str)++;
0073         return 2;
0074     }
0075     if (**str == '-')
0076         return 3;
0077
0078     return 1;
0079 }
0080 EXPORT_SYMBOL(get_option);
0081
0082 /**
0083  *  get_options - Parse a string into a list of integers
0084  *  @str: String to be parsed
0085  *  @nints: size of integer array
0086  *  @ints: integer array (must have room for at least one element)
0087  *
0088  *  This function parses a string containing a comma-separated
0089  *  list of integers, a hyphen-separated range of _positive_ integers,
0090  *  or a combination of both.  The parse halts when the array is
0091  *  full, or when no more numbers can be retrieved from the
0092  *  string.
0093  *
0094  *  When @nints is 0, the function just validates the given @str and
0095  *  returns the amount of parseable integers as described below.
0096  *
0097  *  Returns:
0098  *
0099  *  The first element is filled by the number of collected integers
0100  *  in the range. The rest is what was parsed from the @str.
0101  *
0102  *  Return value is the character in the string which caused
0103  *  the parse to end (typically a null terminator, if @str is
0104  *  completely parseable).
0105  */
0106
0107 char *get_options(const char *str, int nints, int *ints)
0108 {
0109     bool validate = (nints == 0);
0110     int res, i = 1;
0111
0112     while (i < nints || validate) {
0113         int *pint = validate ? ints : ints + i;
0114
0115         res = get_option((char **)&str, pint);
0116         if (res == 0)
0117             break;
0118         if (res == 3) {
0119             int n = validate ? 0 : nints - i;
0120             int range_nums;
0121
0122             range_nums = get_range((char **)&str, pint, n);
0123             if (range_nums < 0)
0124                 break;
0125             /*
0126              * Decrement the result by one to leave out the
0127              * last number in the range.  The next iteration
0128              * will handle the upper number in the range
0129              */
0130             i += (range_nums - 1);
0131         }
0132         i++;
0133         if (res == 1)
0134             break;
0135     }
0136     ints[0] = i - 1;
0137     return (char *)str;
0138 }
0139 EXPORT_SYMBOL(get_options);
0140
0141 /**
0142  *  memparse - parse a string with mem suffixes into a number
0143  *  @ptr: Where parse begins
0144  *  @retptr: (output) Optional pointer to next char after parse completes
0145  *
0146  *  Parses a string into a number.  The number stored at @ptr is
0147  *  potentially suffixed with K, M, G, T, P, E.
0148  */
0149
0150 unsigned long long memparse(const char *ptr, char **retptr)
0151 {
0152     char *endptr;   /* local pointer to end of parsed string */
0153
0154     unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
0155
0156     switch (*endptr) {
0157     case 'E':
0158     case 'e':
0159         ret <<= 10;
0160         fallthrough;
0161     case 'P':
0162     case 'p':
0163         ret <<= 10;
0164         fallthrough;
0165     case 'T':
0166     case 't':
0167         ret <<= 10;
0168         fallthrough;
0169     case 'G':
0170     case 'g':
0171         ret <<= 10;
0172         fallthrough;
0173     case 'M':
0174     case 'm':
0175         ret <<= 10;
0176         fallthrough;
0177     case 'K':
0178     case 'k':
0179         ret <<= 10;
0180         endptr++;
0181         fallthrough;
0182     default:
0183         break;
0184     }
0185
0186     if (retptr)
0187         *retptr = endptr;
0188
0189     return ret;
0190 }
0191 EXPORT_SYMBOL(memparse);
0192
0193 /**
0194  *  parse_option_str - Parse a string and check an option is set or not
0195  *  @str: String to be parsed
0196  *  @option: option name
0197  *
0198  *  This function parses a string containing a comma-separated list of
0199  *  strings like a=b,c.
0200  *
0201  *  Return true if there's such option in the string, or return false.
0202  */
0203 bool parse_option_str(const char *str, const char *option)
0204 {
0205     while (*str) {
0206         if (!strncmp(str, option, strlen(option))) {
0207             str += strlen(option);
0208             if (!*str || *str == ',')
0209                 return true;
0210         }
0211
0212         while (*str && *str != ',')
0213             str++;
0214
0215         if (*str == ',')
0216             str++;
0217     }
0218
0219     return false;
0220 }
0221
0222 /*
0223  * Parse a string to get a param value pair.
0224  * You can use " around spaces, but can't escape ".
0225  * Hyphens and underscores equivalent in parameter names.
0226  */
0227 char *next_arg(char *args, char **param, char **val)
0228 {
0229     unsigned int i, equals = 0;
0230     int in_quote = 0, quoted = 0;
0231
0232     if (*args == '"') {
0233         args++;
0234         in_quote = 1;
0235         quoted = 1;
0236     }
0237
0238     for (i = 0; args[i]; i++) {
0239         if (isspace(args[i]) && !in_quote)
0240             break;
0241         if (equals == 0) {
0242             if (args[i] == '=')
0243                 equals = i;
0244         }
0245         if (args[i] == '"')
0246             in_quote = !in_quote;
0247     }
0248
0249     *param = args;
0250     if (!equals)
0251         *val = NULL;
0252     else {
0253         args[equals] = '\0';
0254         *val = args + equals + 1;
0255
0256         /* Don't include quotes in value. */
0257         if (**val == '"') {
0258             (*val)++;
0259             if (args[i-1] == '"')
0260                 args[i-1] = '\0';
0261         }
0262     }
0263     if (quoted && args[i-1] == '"')
0264         args[i-1] = '\0';
0265
0266     if (args[i]) {
0267         args[i] = '\0';
0268         args += i + 1;
0269     } else
0270         args += i;
0271
0272     /* Chew up trailing spaces. */
0273     return skip_spaces(args);
0274 }
0275 EXPORT_SYMBOL(next_arg);