[mirror_ubuntu-bionic-kernel.git] / lib / parser.c

/*
 * lib/parser.c - simple parser for mount, etc. options.
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/export.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. 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;
	size_t len = s->to - s->from;

	buf = kmalloc(len + 1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	memcpy(buf, s->from, len);
	buf[len] = '\0';

	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. 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;
	size_t len = s->to - s->from;

	buf = kmalloc(len + 1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	memcpy(buf, s->from, len);
	buf[len] = '\0';

	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. 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_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. 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. 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.
 * 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 type wildcardes:
 *   '*' - matches zero or more characters
 *   '?' - matches one character
 * If it's matched, 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().
 */
char *match_strdup(const substring_t *s)
{
	size_t sz = s->to - s->from + 1;
	char *p = kmalloc(sz, GFP_KERNEL);
	if (p)
		match_strlcpy(p, s, sz);
	return p;
}
EXPORT_SYMBOL(match_strdup);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* lib/parser.c - simple parser for mount, etc. options.
	3	*
	4	* This source code is licensed under the GNU General Public License,
	5	* Version 2. See the file COPYING for more details.
	6	*/
	7
	8	#include <linux/ctype.h>
8bc3bcc9 PG	9	#include <linux/types.h>
8bc3bcc9 PG	10	#include <linux/export.h>
1da177e4 LT	11	#include <linux/parser.h>
	12	#include <linux/slab.h>
	13	#include <linux/string.h>
	14
	15	/**
	16	* match_one: - Determines if a string matches a simple pattern
25985edc	17	* @s: the string to examine for presence of the pattern
1da177e4 LT	18	* @p: the string containing the pattern
	19	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	20	* locations.
	21	*
	22	* Description: Determines if the pattern @p is present in string @s. Can only
	23	* match extremely simple token=arg style patterns. If the pattern is found,
	24	* the location(s) of the arguments will be returned in the @args array.
	25	*/
ef4533f8	26	static int match_one(char s, const char p, substring_t args[])
1da177e4 LT	27	{
	28	char *meta;
	29	int argc = 0;
	30
	31	if (!p)
	32	return 1;
	33
	34	while(1) {
	35	int len = -1;
	36	meta = strchr(p, '%');
	37	if (!meta)
	38	return strcmp(p, s) == 0;
	39
	40	if (strncmp(p, s, meta-p))
	41	return 0;
	42
	43	s += meta - p;
	44	p = meta + 1;
	45
	46	if (isdigit(*p))
ef4533f8	47	len = simple_strtoul(p, (char **) &p, 10);
1da177e4 LT	48	else if (*p == '%') {
	49	if (*s++ != '%')
	50	return 0;
	51	p++;
	52	continue;
	53	}
	54
	55	if (argc >= MAX_OPT_ARGS)
	56	return 0;
	57
	58	args[argc].from = s;
	59	switch (*p++) {
b5f54b07 AGR	60	case 's': {
	61	size_t str_len = strlen(s);
	62
	63	if (str_len == 0)
1da177e4	64	return 0;
b5f54b07 AGR	65	if (len == -1 \|\| len > str_len)
b5f54b07 AGR	66	len = str_len;
1da177e4 LT	67	args[argc].to = s + len;
1da177e4 LT	68	break;
b5f54b07	69	}
1da177e4 LT	70	case 'd':
	71	simple_strtol(s, &args[argc].to, 0);
	72	goto num;
	73	case 'u':
	74	simple_strtoul(s, &args[argc].to, 0);
	75	goto num;
	76	case 'o':
	77	simple_strtoul(s, &args[argc].to, 8);
	78	goto num;
	79	case 'x':
	80	simple_strtoul(s, &args[argc].to, 16);
	81	num:
	82	if (args[argc].to == args[argc].from)
	83	return 0;
	84	break;
	85	default:
	86	return 0;
	87	}
	88	s = args[argc].to;
	89	argc++;
	90	}
	91	}
	92
	93	/**
	94	* match_token: - Find a token (and optional args) in a string
	95	* @s: the string to examine for token/argument pairs
	96	* @table: match_table_t describing the set of allowed option tokens and the
	97	* arguments that may be associated with them. Must be terminated with a
	98	* &struct match_token whose pattern is set to the NULL pointer.
	99	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	100	* locations.
	101	*
	102	* Description: Detects which if any of a set of token strings has been passed
	103	* to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
	104	* format identifiers which will be taken into account when matching the
	105	* tokens, and whose locations will be returned in the @args array.
	106	*/
a447c093	107	int match_token(char *s, const match_table_t table, substring_t args[])
1da177e4	108	{
ef4533f8	109	const struct match_token *p;
1da177e4 LT	110
	111	for (p = table; !match_one(s, p->pattern, args) ; p++)
	112	;
	113
	114	return p->token;
	115	}
a3d2cca4	116	EXPORT_SYMBOL(match_token);
1da177e4 LT	117
	118	/**
	119	* match_number: scan a number in the given base from a substring_t
	120	* @s: substring to be scanned
	121	* @result: resulting integer on success
	122	* @base: base to use when converting string
	123	*
	124	* Description: Given a &substring_t and a base, attempts to parse the substring
	125	* as a number in that base. On success, sets @result to the integer represented
77dd3b0b	126	* by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
1da177e4 LT	127	*/
	128	static int match_number(substring_t s, int result, int base)
	129	{
	130	char *endp;
	131	char *buf;
	132	int ret;
77dd3b0b	133	long val;
5d051dec	134	size_t len = s->to - s->from;
1da177e4	135
5d051dec	136	buf = kmalloc(len + 1, GFP_KERNEL);
1da177e4 LT	137	if (!buf)
1da177e4 LT	138	return -ENOMEM;
5d051dec NK	139	memcpy(buf, s->from, len);
5d051dec NK	140	buf[len] = '\0';
77dd3b0b	141
1da177e4	142	ret = 0;
77dd3b0b	143	val = simple_strtol(buf, &endp, base);
1da177e4 LT	144	if (endp == buf)
1da177e4 LT	145	ret = -EINVAL;
77dd3b0b AE	146	else if (val < (long)INT_MIN \|\| val > (long)INT_MAX)
	147	ret = -ERANGE;
	148	else
	149	*result = (int) val;
1da177e4 LT	150	kfree(buf);
	151	return ret;
	152	}
	153
a317178e JS	154	/**
	155	* match_u64int: scan a number in the given base from a substring_t
	156	* @s: substring to be scanned
	157	* @result: resulting u64 on success
	158	* @base: base to use when converting string
	159	*
	160	* Description: Given a &substring_t and a base, attempts to parse the substring
	161	* as a number in that base. On success, sets @result to the integer represented
	162	* by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	163	*/
	164	static int match_u64int(substring_t s, u64 result, int base)
	165	{
	166	char *buf;
	167	int ret;
	168	u64 val;
	169	size_t len = s->to - s->from;
	170
	171	buf = kmalloc(len + 1, GFP_KERNEL);
	172	if (!buf)
	173	return -ENOMEM;
	174	memcpy(buf, s->from, len);
	175	buf[len] = '\0';
	176
	177	ret = kstrtoull(buf, base, &val);
	178	if (!ret)
	179	*result = val;
	180	kfree(buf);
	181	return ret;
	182	}
	183
1da177e4 LT	184	/**
	185	* match_int: - scan a decimal representation of an integer from a substring_t
	186	* @s: substring_t to be scanned
	187	* @result: resulting integer on success
	188	*
	189	* Description: Attempts to parse the &substring_t @s as a decimal integer. On
	190	* success, sets @result to the integer represented by the string and returns 0.
53769627	191	* Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
1da177e4 LT	192	*/
	193	int match_int(substring_t s, int result)
	194	{
	195	return match_number(s, result, 0);
	196	}
a3d2cca4	197	EXPORT_SYMBOL(match_int);
1da177e4	198
a317178e JS	199	/**
	200	* match_u64: - scan a decimal representation of a u64 from
	201	* a substring_t
	202	* @s: substring_t to be scanned
	203	* @result: resulting unsigned long long on success
	204	*
	205	* Description: Attempts to parse the &substring_t @s as a long decimal
	206	* integer. On success, sets @result to the integer represented by the
	207	* string and returns 0.
	208	* Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
	209	*/
	210	int match_u64(substring_t s, u64 result)
	211	{
	212	return match_u64int(s, result, 0);
	213	}
	214	EXPORT_SYMBOL(match_u64);
	215
1da177e4 LT	216	/**
	217	* match_octal: - scan an octal representation of an integer from a substring_t
	218	* @s: substring_t to be scanned
	219	* @result: resulting integer on success
	220	*
	221	* Description: Attempts to parse the &substring_t @s as an octal integer. On
	222	* success, sets @result to the integer represented by the string and returns
53769627	223	* 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
1da177e4 LT	224	*/
	225	int match_octal(substring_t s, int result)
	226	{
	227	return match_number(s, result, 8);
	228	}
a3d2cca4	229	EXPORT_SYMBOL(match_octal);
1da177e4 LT	230
	231	/**
	232	* match_hex: - scan a hex representation of an integer from a substring_t
	233	* @s: substring_t to be scanned
	234	* @result: resulting integer on success
	235	*
	236	* Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
	237	* On success, sets @result to the integer represented by the string and
53769627	238	* returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
1da177e4 LT	239	*/
	240	int match_hex(substring_t s, int result)
	241	{
	242	return match_number(s, result, 16);
	243	}
a3d2cca4	244	EXPORT_SYMBOL(match_hex);
1da177e4	245
aace0509 DC	246	/**
	247	* match_wildcard: - parse if a string matches given wildcard pattern
	248	* @pattern: wildcard pattern
	249	* @str: the string to be parsed
	250	*
	251	* Description: Parse the string @str to check if matches wildcard
	252	* pattern @pattern. The pattern may contain two type wildcardes:
	253	* '*' - matches zero or more characters
	254	* '?' - matches one character
	255	* If it's matched, return true, else return false.
	256	*/
	257	bool match_wildcard(const char pattern, const char str)
	258	{
	259	const char *s = str;
	260	const char *p = pattern;
	261	bool star = false;
	262
	263	while (*s) {
	264	switch (*p) {
	265	case '?':
	266	s++;
	267	p++;
	268	break;
	269	case '*':
	270	star = true;
	271	str = s;
	272	if (!*++p)
	273	return true;
	274	pattern = p;
	275	break;
	276	default:
	277	if (s == p) {
	278	s++;
	279	p++;
	280	} else {
	281	if (!star)
	282	return false;
	283	str++;
	284	s = str;
	285	p = pattern;
	286	}
	287	break;
	288	}
	289	}
	290
	291	if (p == '')
	292	++p;
	293	return !*p;
	294	}
a3d2cca4	295	EXPORT_SYMBOL(match_wildcard);
aace0509	296
1da177e4	297	/**
b32a09db MA	298	* match_strlcpy: - Copy the characters from a substring_t to a sized buffer
	299	* @dest: where to copy to
	300	* @src: &substring_t to copy
	301	* @size: size of destination buffer
1da177e4	302	*
b32a09db MA	303	* Description: Copy the characters in &substring_t @src to the
	304	* c-style string @dest. Copy no more than @size - 1 characters, plus
	305	* the terminating NUL. Return length of @src.
1da177e4	306	*/
b32a09db	307	size_t match_strlcpy(char dest, const substring_t src, size_t size)
1da177e4	308	{
b32a09db MA	309	size_t ret = src->to - src->from;
	310
	311	if (size) {
	312	size_t len = ret >= size ? size - 1 : ret;
	313	memcpy(dest, src->from, len);
	314	dest[len] = '\0';
	315	}
	316	return ret;
1da177e4	317	}
a3d2cca4	318	EXPORT_SYMBOL(match_strlcpy);
1da177e4 LT	319
	320	/**
	321	* match_strdup: - allocate a new string with the contents of a substring_t
	322	* @s: &substring_t to copy
	323	*
	324	* Description: Allocates and returns a string filled with the contents of
	325	* the &substring_t @s. The caller is responsible for freeing the returned
	326	* string with kfree().
	327	*/
ef4533f8	328	char match_strdup(const substring_t s)
1da177e4	329	{
b32a09db MA	330	size_t sz = s->to - s->from + 1;
b32a09db MA	331	char *p = kmalloc(sz, GFP_KERNEL);
1da177e4	332	if (p)
b32a09db	333	match_strlcpy(p, s, sz);
1da177e4 LT	334	return p;
1da177e4 LT	335	}
1da177e4	336	EXPORT_SYMBOL(match_strdup);