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![Masahiro Yamada](/assets/img/avatar_default.png)
The local variable 'next' is unneeded because you can simply advance the existing pointer 'args'. Link: https://lkml.kernel.org/r/20210201014707.3828753-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
274 lines
5.8 KiB
C
274 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/lib/cmdline.c
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* Helper functions generally used for parsing kernel command line
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* and module options.
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*
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* Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
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*
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* GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
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*/
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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/*
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* If a hyphen was found in get_option, this will handle the
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* range of numbers, M-N. This will expand the range and insert
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* the values[M, M+1, ..., N] into the ints array in get_options.
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*/
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static int get_range(char **str, int *pint, int n)
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{
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int x, inc_counter, upper_range;
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(*str)++;
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upper_range = simple_strtol((*str), NULL, 0);
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inc_counter = upper_range - *pint;
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for (x = *pint; n && x < upper_range; x++, n--)
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*pint++ = x;
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return inc_counter;
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}
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/**
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* get_option - Parse integer from an option string
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* @str: option string
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* @pint: (optional output) integer value parsed from @str
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*
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* Read an int from an option string; if available accept a subsequent
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* comma as well.
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*
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* When @pint is NULL the function can be used as a validator of
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* the current option in the string.
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*
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* Return values:
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* 0 - no int in string
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* 1 - int found, no subsequent comma
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* 2 - int found including a subsequent comma
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* 3 - hyphen found to denote a range
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*
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* Leading hyphen without integer is no integer case, but we consume it
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* for the sake of simplification.
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*/
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int get_option(char **str, int *pint)
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{
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char *cur = *str;
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int value;
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if (!cur || !(*cur))
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return 0;
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if (*cur == '-')
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value = -simple_strtoull(++cur, str, 0);
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else
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value = simple_strtoull(cur, str, 0);
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if (pint)
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*pint = value;
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if (cur == *str)
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return 0;
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if (**str == ',') {
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(*str)++;
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return 2;
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}
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if (**str == '-')
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return 3;
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return 1;
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}
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EXPORT_SYMBOL(get_option);
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/**
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* get_options - Parse a string into a list of integers
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* @str: String to be parsed
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* @nints: size of integer array
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* @ints: integer array (must have room for at least one element)
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*
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* This function parses a string containing a comma-separated
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* list of integers, a hyphen-separated range of _positive_ integers,
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* or a combination of both. The parse halts when the array is
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* full, or when no more numbers can be retrieved from the
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* string.
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*
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* When @nints is 0, the function just validates the given @str and
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* returns the amount of parseable integers as described below.
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*
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* Returns:
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*
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* The first element is filled by the number of collected integers
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* in the range. The rest is what was parsed from the @str.
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*
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* Return value is the character in the string which caused
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* the parse to end (typically a null terminator, if @str is
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* completely parseable).
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*/
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char *get_options(const char *str, int nints, int *ints)
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{
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bool validate = (nints == 0);
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int res, i = 1;
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while (i < nints || validate) {
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int *pint = validate ? ints : ints + i;
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res = get_option((char **)&str, pint);
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if (res == 0)
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break;
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if (res == 3) {
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int n = validate ? 0 : nints - i;
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int range_nums;
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range_nums = get_range((char **)&str, pint, n);
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if (range_nums < 0)
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break;
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/*
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* Decrement the result by one to leave out the
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* last number in the range. The next iteration
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* will handle the upper number in the range
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*/
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i += (range_nums - 1);
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}
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i++;
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if (res == 1)
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break;
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}
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ints[0] = i - 1;
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return (char *)str;
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}
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EXPORT_SYMBOL(get_options);
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/**
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* memparse - parse a string with mem suffixes into a number
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* @ptr: Where parse begins
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* @retptr: (output) Optional pointer to next char after parse completes
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*
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* Parses a string into a number. The number stored at @ptr is
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* potentially suffixed with K, M, G, T, P, E.
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*/
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unsigned long long memparse(const char *ptr, char **retptr)
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{
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char *endptr; /* local pointer to end of parsed string */
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unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
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switch (*endptr) {
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case 'E':
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case 'e':
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ret <<= 10;
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fallthrough;
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case 'P':
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case 'p':
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ret <<= 10;
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fallthrough;
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case 'T':
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case 't':
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ret <<= 10;
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fallthrough;
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case 'G':
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case 'g':
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ret <<= 10;
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fallthrough;
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case 'M':
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case 'm':
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ret <<= 10;
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fallthrough;
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case 'K':
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case 'k':
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ret <<= 10;
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endptr++;
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fallthrough;
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default:
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break;
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}
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if (retptr)
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*retptr = endptr;
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return ret;
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}
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EXPORT_SYMBOL(memparse);
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/**
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* parse_option_str - Parse a string and check an option is set or not
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* @str: String to be parsed
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* @option: option name
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*
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* This function parses a string containing a comma-separated list of
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* strings like a=b,c.
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*
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* Return true if there's such option in the string, or return false.
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*/
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bool parse_option_str(const char *str, const char *option)
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{
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while (*str) {
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if (!strncmp(str, option, strlen(option))) {
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str += strlen(option);
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if (!*str || *str == ',')
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return true;
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}
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while (*str && *str != ',')
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str++;
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if (*str == ',')
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str++;
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}
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return false;
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}
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/*
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* Parse a string to get a param value pair.
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* You can use " around spaces, but can't escape ".
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* Hyphens and underscores equivalent in parameter names.
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*/
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char *next_arg(char *args, char **param, char **val)
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{
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unsigned int i, equals = 0;
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int in_quote = 0, quoted = 0;
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if (*args == '"') {
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args++;
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in_quote = 1;
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quoted = 1;
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}
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for (i = 0; args[i]; i++) {
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if (isspace(args[i]) && !in_quote)
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break;
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if (equals == 0) {
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if (args[i] == '=')
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equals = i;
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}
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if (args[i] == '"')
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in_quote = !in_quote;
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}
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*param = args;
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if (!equals)
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*val = NULL;
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else {
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args[equals] = '\0';
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*val = args + equals + 1;
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/* Don't include quotes in value. */
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if (**val == '"') {
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(*val)++;
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if (args[i-1] == '"')
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args[i-1] = '\0';
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}
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}
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if (quoted && args[i-1] == '"')
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args[i-1] = '\0';
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if (args[i]) {
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args[i] = '\0';
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args += i + 1;
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} else
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args += i;
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/* Chew up trailing spaces. */
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return skip_spaces(args);
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}
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