lib/parser.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * lib/parser.c - simple parser for mount, etc. options.
  */

 #include <linux/ctype.h>
 #include <linux/types.h>
 #include <linux/export.h>
 #include <linux/kstrtox.h>
 #include <linux/parser.h>
 #include <linux/slab.h>
 #include <linux/string.h>

 /**
  * match_one - Determines if a string matches a simple pattern
  * @s: the string to examine for presence of the pattern
  * @p: the string containing the pattern
  * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
  * locations.
  *
  * Description: Determines if the pattern @p is present in string @s. Can only
  * match extremely simple token=arg style patterns. If the pattern is found,
  * the location(s) of the arguments will be returned in the @args array.
  */
 static int match_one(char *s, const char *p, substring_t args[])
 {
 	char *meta;
 	int argc = 0;

 	if (!p)
 		return 1;

 	while(1) {
 		int len = -1;
 		meta = strchr(p, '%');
 		if (!meta)
 			return strcmp(p, s) == 0;

 		if (strncmp(p, s, meta-p))
 			return 0;

 		s += meta - p;
 		p = meta + 1;

 		if (isdigit(*p))
 			len = simple_strtoul(p, (char **) &p, 10);
 		else if (*p == '%') {
 			if (*s++ != '%')
 				return 0;
 			p++;
 			continue;
 		}

 		if (argc >= MAX_OPT_ARGS)
 			return 0;

 		args[argc].from = s;
 		switch (*p++) {
 		case 's': {
 			size_t str_len = strlen(s);

 			if (str_len == 0)
 				return 0;
 			if (len == -1 || len > str_len)
 				len = str_len;
 			args[argc].to = s + len;
 			break;
 		}
 		case 'd':
 			simple_strtol(s, &args[argc].to, 0);
 			goto num;
 		case 'u':
 			simple_strtoul(s, &args[argc].to, 0);
 			goto num;
 		case 'o':
 			simple_strtoul(s, &args[argc].to, 8);
 			goto num;
 		case 'x':
 			simple_strtoul(s, &args[argc].to, 16);
 		num:
 			if (args[argc].to == args[argc].from)
 				return 0;
 			break;
 		default:
 			return 0;
 		}
 		s = args[argc].to;
 		argc++;
 	}
 }

 /**
  * match_token - Find a token (and optional args) in a string
  * @s: the string to examine for token/argument pairs
  * @table: match_table_t describing the set of allowed option tokens and the
  * arguments that may be associated with them. Must be terminated with a
  * &struct match_token whose pattern is set to the NULL pointer.
  * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
  * locations.
  *
  * Description: Detects which if any of a set of token strings has been passed
  * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style
  * format identifiers which will be taken into account when matching the
  * tokens, and whose locations will be returned in the @args array.
  */
 int match_token(char *s, const match_table_t table, substring_t args[])
 {
 	const struct match_token *p;

 	for (p = table; !match_one(s, p->pattern, args) ; p++)
 		;

 	return p->token;
 }
 EXPORT_SYMBOL(match_token);

 /**
  * match_number - scan a number in the given base from a substring_t
  * @s: substring to be scanned
  * @result: resulting integer on success
  * @base: base to use when converting string
  *
  * Description: Given a &substring_t and a base, attempts to parse the substring
  * as a number in that base.
  *
  * Return: On success, sets @result to the integer represented by the
  * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 static int match_number(substring_t *s, int *result, int base)
 {
 	char *endp;
 	char *buf;
 	int ret;
 	long val;

 	buf = match_strdup(s);
 	if (!buf)
 		return -ENOMEM;

 	ret = 0;
 	val = simple_strtol(buf, &endp, base);
 	if (endp == buf)
 		ret = -EINVAL;
 	else if (val < (long)INT_MIN || val > (long)INT_MAX)
 		ret = -ERANGE;
 	else
 		*result = (int) val;
 	kfree(buf);
 	return ret;
 }

 /**
  * match_u64int - scan a number in the given base from a substring_t
  * @s: substring to be scanned
  * @result: resulting u64 on success
  * @base: base to use when converting string
  *
  * Description: Given a &substring_t and a base, attempts to parse the substring
  * as a number in that base.
  *
  * Return: On success, sets @result to the integer represented by the
  * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 static int match_u64int(substring_t *s, u64 *result, int base)
 {
 	char *buf;
 	int ret;
 	u64 val;

 	buf = match_strdup(s);
 	if (!buf)
 		return -ENOMEM;

 	ret = kstrtoull(buf, base, &val);
 	if (!ret)
 		*result = val;
 	kfree(buf);
 	return ret;
 }

 /**
  * match_int - scan a decimal representation of an integer from a substring_t
  * @s: substring_t to be scanned
  * @result: resulting integer on success
  *
  * Description: Attempts to parse the &substring_t @s as a decimal integer.
  *
  * Return: On success, sets @result to the integer represented by the string
  * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 int match_int(substring_t *s, int *result)
 {
 	return match_number(s, result, 0);
 }
 EXPORT_SYMBOL(match_int);

 /**
  * match_uint - scan a decimal representation of an integer from a substring_t
  * @s: substring_t to be scanned
  * @result: resulting integer on success
  *
  * Description: Attempts to parse the &substring_t @s as a decimal integer.
  *
  * Return: On success, sets @result to the integer represented by the string
  * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 int match_uint(substring_t *s, unsigned int *result)
 {
 	int err = -ENOMEM;
 	char *buf = match_strdup(s);

 	if (buf) {
 		err = kstrtouint(buf, 10, result);
 		kfree(buf);
 	}
 	return err;
 }
 EXPORT_SYMBOL(match_uint);

 /**
  * match_u64 - scan a decimal representation of a u64 from
  *                  a substring_t
  * @s: substring_t to be scanned
  * @result: resulting unsigned long long on success
  *
  * Description: Attempts to parse the &substring_t @s as a long decimal
  * integer.
  *
  * Return: On success, sets @result to the integer represented by the string
  * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 int match_u64(substring_t *s, u64 *result)
 {
 	return match_u64int(s, result, 0);
 }
 EXPORT_SYMBOL(match_u64);

 /**
  * match_octal - scan an octal representation of an integer from a substring_t
  * @s: substring_t to be scanned
  * @result: resulting integer on success
  *
  * Description: Attempts to parse the &substring_t @s as an octal integer.
  *
  * Return: On success, sets @result to the integer represented by the string
  * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 int match_octal(substring_t *s, int *result)
 {
 	return match_number(s, result, 8);
 }
 EXPORT_SYMBOL(match_octal);

 /**
  * match_hex - scan a hex representation of an integer from a substring_t
  * @s: substring_t to be scanned
  * @result: resulting integer on success
  *
  * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
  *
  * Return: On success, sets @result to the integer represented by the string
  * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
  */
 int match_hex(substring_t *s, int *result)
 {
 	return match_number(s, result, 16);
 }
 EXPORT_SYMBOL(match_hex);

 /**
  * match_wildcard - parse if a string matches given wildcard pattern
  * @pattern: wildcard pattern
  * @str: the string to be parsed
  *
  * Description: Parse the string @str to check if matches wildcard
  * pattern @pattern. The pattern may contain two types of wildcards:
  *   '*' - matches zero or more characters
  *   '?' - matches one character
  *
  * Return: If the @str matches the @pattern, return true, else return false.
  */
 bool match_wildcard(const char *pattern, const char *str)
 {
 	const char *s = str;
 	const char *p = pattern;
 	bool star = false;

 	while (*s) {
 		switch (*p) {
 		case '?':
 			s++;
 			p++;
 			break;
 		case '*':
 			star = true;
 			str = s;
 			if (!*++p)
 				return true;
 			pattern = p;
 			break;
 		default:
 			if (*s == *p) {
 				s++;
 				p++;
 			} else {
 				if (!star)
 					return false;
 				str++;
 				s = str;
 				p = pattern;
 			}
 			break;
 		}
 	}

 	if (*p == '*')
 		++p;
 	return !*p;
 }
 EXPORT_SYMBOL(match_wildcard);

 /**
  * match_strlcpy - Copy the characters from a substring_t to a sized buffer
  * @dest: where to copy to
  * @src: &substring_t to copy
  * @size: size of destination buffer
  *
  * Description: Copy the characters in &substring_t @src to the
  * c-style string @dest.  Copy no more than @size - 1 characters, plus
  * the terminating NUL.
  *
  * Return: length of @src.
  */
 size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
 {
 	size_t ret = src->to - src->from;

 	if (size) {
 		size_t len = ret >= size ? size - 1 : ret;
 		memcpy(dest, src->from, len);
 		dest[len] = '\0';
 	}
 	return ret;
 }
 EXPORT_SYMBOL(match_strlcpy);

 /**
  * match_strdup - allocate a new string with the contents of a substring_t
  * @s: &substring_t to copy
  *
  * Description: Allocates and returns a string filled with the contents of
  * the &substring_t @s. The caller is responsible for freeing the returned
  * string with kfree().
  *
  * Return: the address of the newly allocated NUL-terminated string or
  * %NULL on error.
  */
 char *match_strdup(const substring_t *s)
 {
 	return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
 }
 EXPORT_SYMBOL(match_strdup);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* lib/parser.c - simple parser for mount, etc. options.
	*/

	#include <linux/ctype.h>
	#include <linux/types.h>
	#include <linux/export.h>
	#include <linux/kstrtox.h>
	#include <linux/parser.h>
	#include <linux/slab.h>
	#include <linux/string.h>

	/**
	* match_one - Determines if a string matches a simple pattern
	* @s: the string to examine for presence of the pattern
	* @p: the string containing the pattern
	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	* locations.
	*
	* Description: Determines if the pattern @p is present in string @s. Can only
	* match extremely simple token=arg style patterns. If the pattern is found,
	* the location(s) of the arguments will be returned in the @args array.
	*/
	static int match_one(char s, const char p, substring_t args[])
	{
	char *meta;
	int argc = 0;

	if (!p)
	return 1;

	while(1) {
	int len = -1;
	meta = strchr(p, '%');
	if (!meta)
	return strcmp(p, s) == 0;

	if (strncmp(p, s, meta-p))
	return 0;

	s += meta - p;
	p = meta + 1;

	if (isdigit(*p))
	len = simple_strtoul(p, (char **) &p, 10);
	else if (*p == '%') {
	if (*s++ != '%')
	return 0;
	p++;
	continue;
	}

	if (argc >= MAX_OPT_ARGS)
	return 0;

	args[argc].from = s;
	switch (*p++) {
	case 's': {
	size_t str_len = strlen(s);

	if (str_len == 0)
	return 0;
	if (len == -1 \|\| len > str_len)
	len = str_len;
	args[argc].to = s + len;
	break;
	}
	case 'd':
	simple_strtol(s, &args[argc].to, 0);
	goto num;
	case 'u':
	simple_strtoul(s, &args[argc].to, 0);
	goto num;
	case 'o':
	simple_strtoul(s, &args[argc].to, 8);
	goto num;
	case 'x':
	simple_strtoul(s, &args[argc].to, 16);
	num:
	if (args[argc].to == args[argc].from)
	return 0;
	break;
	default:
	return 0;
	}
	s = args[argc].to;
	argc++;
	}
	}

	/**
	* match_token - Find a token (and optional args) in a string
	* @s: the string to examine for token/argument pairs
	* @table: match_table_t describing the set of allowed option tokens and the
	* arguments that may be associated with them. Must be terminated with a
	* &struct match_token whose pattern is set to the NULL pointer.
	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	* locations.
	*
	* Description: Detects which if any of a set of token strings has been passed
	* to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style
	* format identifiers which will be taken into account when matching the
	* tokens, and whose locations will be returned in the @args array.
	*/
	int match_token(char *s, const match_table_t table, substring_t args[])
	{
	const struct match_token *p;

	for (p = table; !match_one(s, p->pattern, args) ; p++)
	;

	return p->token;
	}
	EXPORT_SYMBOL(match_token);

	/**
	* match_number - scan a number in the given base from a substring_t
	* @s: substring to be scanned
	* @result: resulting integer on success
	* @base: base to use when converting string
	*
	* Description: Given a &substring_t and a base, attempts to parse the substring
	* as a number in that base.
	*
	* Return: On success, sets @result to the integer represented by the
	* string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	static int match_number(substring_t s, int result, int base)
	{
	char *endp;
	char *buf;
	int ret;
	long val;

	buf = match_strdup(s);
	if (!buf)
	return -ENOMEM;

	ret = 0;
	val = simple_strtol(buf, &endp, base);
	if (endp == buf)
	ret = -EINVAL;
	else if (val < (long)INT_MIN \|\| val > (long)INT_MAX)
	ret = -ERANGE;
	else
	*result = (int) val;
	kfree(buf);
	return ret;
	}

	/**
	* match_u64int - scan a number in the given base from a substring_t
	* @s: substring to be scanned
	* @result: resulting u64 on success
	* @base: base to use when converting string
	*
	* Description: Given a &substring_t and a base, attempts to parse the substring
	* as a number in that base.
	*
	* Return: On success, sets @result to the integer represented by the
	* string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	static int match_u64int(substring_t s, u64 result, int base)
	{
	char *buf;
	int ret;
	u64 val;

	buf = match_strdup(s);
	if (!buf)
	return -ENOMEM;

	ret = kstrtoull(buf, base, &val);
	if (!ret)
	*result = val;
	kfree(buf);
	return ret;
	}

	/**
	* match_int - scan a decimal representation of an integer from a substring_t
	* @s: substring_t to be scanned
	* @result: resulting integer on success
	*
	* Description: Attempts to parse the &substring_t @s as a decimal integer.
	*
	* Return: On success, sets @result to the integer represented by the string
	* and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	int match_int(substring_t s, int result)
	{
	return match_number(s, result, 0);
	}
	EXPORT_SYMBOL(match_int);

	/**
	* match_uint - scan a decimal representation of an integer from a substring_t
	* @s: substring_t to be scanned
	* @result: resulting integer on success
	*
	* Description: Attempts to parse the &substring_t @s as a decimal integer.
	*
	* Return: On success, sets @result to the integer represented by the string
	* and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	int match_uint(substring_t s, unsigned int result)
	{
	int err = -ENOMEM;
	char *buf = match_strdup(s);

	if (buf) {
	err = kstrtouint(buf, 10, result);
	kfree(buf);
	}
	return err;
	}
	EXPORT_SYMBOL(match_uint);

	/**
	* match_u64 - scan a decimal representation of a u64 from
	* a substring_t
	* @s: substring_t to be scanned
	* @result: resulting unsigned long long on success
	*
	* Description: Attempts to parse the &substring_t @s as a long decimal
	* integer.
	*
	* Return: On success, sets @result to the integer represented by the string
	* and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	int match_u64(substring_t s, u64 result)
	{
	return match_u64int(s, result, 0);
	}
	EXPORT_SYMBOL(match_u64);

	/**
	* match_octal - scan an octal representation of an integer from a substring_t
	* @s: substring_t to be scanned
	* @result: resulting integer on success
	*
	* Description: Attempts to parse the &substring_t @s as an octal integer.
	*
	* Return: On success, sets @result to the integer represented by the string
	* and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	int match_octal(substring_t s, int result)
	{
	return match_number(s, result, 8);
	}
	EXPORT_SYMBOL(match_octal);

	/**
	* match_hex - scan a hex representation of an integer from a substring_t
	* @s: substring_t to be scanned
	* @result: resulting integer on success
	*
	* Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
	*
	* Return: On success, sets @result to the integer represented by the string
	* and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	*/
	int match_hex(substring_t s, int result)
	{
	return match_number(s, result, 16);
	}
	EXPORT_SYMBOL(match_hex);

	/**
	* match_wildcard - parse if a string matches given wildcard pattern
	* @pattern: wildcard pattern
	* @str: the string to be parsed
	*
	* Description: Parse the string @str to check if matches wildcard
	* pattern @pattern. The pattern may contain two types of wildcards:
	* '*' - matches zero or more characters
	* '?' - matches one character
	*
	* Return: If the @str matches the @pattern, return true, else return false.
	*/
	bool match_wildcard(const char pattern, const char str)
	{
	const char *s = str;
	const char *p = pattern;
	bool star = false;

	while (*s) {
	switch (*p) {
	case '?':
	s++;
	p++;
	break;
	case '*':
	star = true;
	str = s;
	if (!*++p)
	return true;
	pattern = p;
	break;
	default:
	if (s == p) {
	s++;
	p++;
	} else {
	if (!star)
	return false;
	str++;
	s = str;
	p = pattern;
	}
	break;
	}
	}

	if (p == '')
	++p;
	return !*p;
	}
	EXPORT_SYMBOL(match_wildcard);

	/**
	* match_strlcpy - Copy the characters from a substring_t to a sized buffer
	* @dest: where to copy to
	* @src: &substring_t to copy
	* @size: size of destination buffer
	*
	* Description: Copy the characters in &substring_t @src to the
	* c-style string @dest. Copy no more than @size - 1 characters, plus
	* the terminating NUL.
	*
	* Return: length of @src.
	*/
	size_t match_strlcpy(char dest, const substring_t src, size_t size)
	{
	size_t ret = src->to - src->from;

	if (size) {
	size_t len = ret >= size ? size - 1 : ret;
	memcpy(dest, src->from, len);
	dest[len] = '\0';
	}
	return ret;
	}
	EXPORT_SYMBOL(match_strlcpy);

	/**
	* match_strdup - allocate a new string with the contents of a substring_t
	* @s: &substring_t to copy
	*
	* Description: Allocates and returns a string filled with the contents of
	* the &substring_t @s. The caller is responsible for freeing the returned
	* string with kfree().
	*
	* Return: the address of the newly allocated NUL-terminated string or
	* %NULL on error.
	*/
	char match_strdup(const substring_t s)
	{
	return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
	}
	EXPORT_SYMBOL(match_strdup);