linux/lib/cmdline.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/lib/cmdline.c
 * Helper functions generally used for parsing kernel command line
 * and module options.
 *
 * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
 *
 * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ctype.h>

/*
 *	If a hyphen was found in get_option, this will handle the
 *	range of numbers, M-N.  This will expand the range and insert
 *	the values[M, M+1, ..., N] into the ints array in get_options.
 */

static int get_range(char **str, int *pint, int n)
{ … }

/**
 *	get_option - Parse integer from an option string
 *	@str: option string
 *	@pint: (optional output) integer value parsed from @str
 *
 *	Read an int from an option string; if available accept a subsequent
 *	comma as well.
 *
 *	When @pint is NULL the function can be used as a validator of
 *	the current option in the string.
 *
 *	Return values:
 *	0 - no int in string
 *	1 - int found, no subsequent comma
 *	2 - int found including a subsequent comma
 *	3 - hyphen found to denote a range
 *
 *	Leading hyphen without integer is no integer case, but we consume it
 *	for the sake of simplification.
 */

int get_option(char **str, int *pint)
{ … }
EXPORT_SYMBOL(get_option);

/**
 *	get_options - Parse a string into a list of integers
 *	@str: String to be parsed
 *	@nints: size of integer array
 *	@ints: integer array (must have room for at least one element)
 *
 *	This function parses a string containing a comma-separated
 *	list of integers, a hyphen-separated range of _positive_ integers,
 *	or a combination of both.  The parse halts when the array is
 *	full, or when no more numbers can be retrieved from the
 *	string.
 *
 *	When @nints is 0, the function just validates the given @str and
 *	returns the amount of parseable integers as described below.
 *
 *	Returns:
 *
 *	The first element is filled by the number of collected integers
 *	in the range. The rest is what was parsed from the @str.
 *
 *	Return value is the character in the string which caused
 *	the parse to end (typically a null terminator, if @str is
 *	completely parseable).
 */

char *get_options(const char *str, int nints, int *ints)
{ … }
EXPORT_SYMBOL(get_options);

/**
 *	memparse - parse a string with mem suffixes into a number
 *	@ptr: Where parse begins
 *	@retptr: (output) Optional pointer to next char after parse completes
 *
 *	Parses a string into a number.  The number stored at @ptr is
 *	potentially suffixed with K, M, G, T, P, E.
 */

unsigned long long memparse(const char *ptr, char **retptr)
{ … }
EXPORT_SYMBOL(memparse);

/**
 *	parse_option_str - Parse a string and check an option is set or not
 *	@str: String to be parsed
 *	@option: option name
 *
 *	This function parses a string containing a comma-separated list of
 *	strings like a=b,c.
 *
 *	Return true if there's such option in the string, or return false.
 */
bool parse_option_str(const char *str, const char *option)
{ … }

/*
 * Parse a string to get a param value pair.
 * You can use " around spaces, but can't escape ".
 * Hyphens and underscores equivalent in parameter names.
 */
char *next_arg(char *args, char **param, char **val)
{ … }
EXPORT_SYMBOL(next_arg);