[net-next-2.6.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/module.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 presense 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;
}

/**
 * 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 either -ENOMEM or -EINVAL on failure.
 */
static int match_number(substring_t *s, int *result, int base)
{
	char *endp;
	char *buf;
	int ret;

	buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	memcpy(buf, s->from, s->to - s->from);
	buf[s->to - s->from] = '\0';
	*result = simple_strtol(buf, &endp, base);
	ret = 0;
	if (endp == buf)
		ret = -EINVAL;
	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 either -ENOMEM or -EINVAL on failure.
 */
int match_int(substring_t *s, int *result)
{
	return match_number(s, result, 0);
}

/**
 * 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 either -ENOMEM or -EINVAL on failure.
 */
int match_octal(substring_t *s, int *result)
{
	return match_number(s, result, 8);
}

/**
 * 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 either -ENOMEM or -EINVAL on failure.
 */
int match_hex(substring_t *s, int *result)
{
	return match_number(s, result, 16);
}

/**
 * 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;
}

/**
 * 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_token);
EXPORT_SYMBOL(match_int);
EXPORT_SYMBOL(match_octal);
EXPORT_SYMBOL(match_hex);
EXPORT_SYMBOL(match_strlcpy);
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>
	9	#include <linux/module.h>
	10	#include <linux/parser.h>
	11	#include <linux/slab.h>
	12	#include <linux/string.h>
	13
	14	/**
	15	* match_one: - Determines if a string matches a simple pattern
	16	* @s: the string to examine for presense of the pattern
	17	* @p: the string containing the pattern
	18	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	19	* locations.
	20	*
	21	* Description: Determines if the pattern @p is present in string @s. Can only
	22	* match extremely simple token=arg style patterns. If the pattern is found,
	23	* the location(s) of the arguments will be returned in the @args array.
	24	*/
ef4533f8	25	static int match_one(char s, const char p, substring_t args[])
1da177e4 LT	26	{
	27	char *meta;
	28	int argc = 0;
	29
	30	if (!p)
	31	return 1;
	32
	33	while(1) {
	34	int len = -1;
	35	meta = strchr(p, '%');
	36	if (!meta)
	37	return strcmp(p, s) == 0;
	38
	39	if (strncmp(p, s, meta-p))
	40	return 0;
	41
	42	s += meta - p;
	43	p = meta + 1;
	44
	45	if (isdigit(*p))
ef4533f8	46	len = simple_strtoul(p, (char **) &p, 10);
1da177e4 LT	47	else if (*p == '%') {
	48	if (*s++ != '%')
	49	return 0;
	50	p++;
	51	continue;
	52	}
	53
	54	if (argc >= MAX_OPT_ARGS)
	55	return 0;
	56
	57	args[argc].from = s;
	58	switch (*p++) {
b5f54b07 AGR	59	case 's': {
	60	size_t str_len = strlen(s);
	61
	62	if (str_len == 0)
1da177e4	63	return 0;
b5f54b07 AGR	64	if (len == -1 \|\| len > str_len)
b5f54b07 AGR	65	len = str_len;
1da177e4 LT	66	args[argc].to = s + len;
1da177e4 LT	67	break;
b5f54b07	68	}
1da177e4 LT	69	case 'd':
	70	simple_strtol(s, &args[argc].to, 0);
	71	goto num;
	72	case 'u':
	73	simple_strtoul(s, &args[argc].to, 0);
	74	goto num;
	75	case 'o':
	76	simple_strtoul(s, &args[argc].to, 8);
	77	goto num;
	78	case 'x':
	79	simple_strtoul(s, &args[argc].to, 16);
	80	num:
	81	if (args[argc].to == args[argc].from)
	82	return 0;
	83	break;
	84	default:
	85	return 0;
	86	}
	87	s = args[argc].to;
	88	argc++;
	89	}
	90	}
	91
	92	/**
	93	* match_token: - Find a token (and optional args) in a string
	94	* @s: the string to examine for token/argument pairs
	95	* @table: match_table_t describing the set of allowed option tokens and the
	96	* arguments that may be associated with them. Must be terminated with a
	97	* &struct match_token whose pattern is set to the NULL pointer.
	98	* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
	99	* locations.
	100	*
	101	* Description: Detects which if any of a set of token strings has been passed
	102	* to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
	103	* format identifiers which will be taken into account when matching the
	104	* tokens, and whose locations will be returned in the @args array.
	105	*/
a447c093	106	int match_token(char *s, const match_table_t table, substring_t args[])
1da177e4	107	{
ef4533f8	108	const struct match_token *p;
1da177e4 LT	109
	110	for (p = table; !match_one(s, p->pattern, args) ; p++)
	111	;
	112
	113	return p->token;
	114	}
	115
	116	/**
	117	* match_number: scan a number in the given base from a substring_t
	118	* @s: substring to be scanned
	119	* @result: resulting integer on success
	120	* @base: base to use when converting string
	121	*
	122	* Description: Given a &substring_t and a base, attempts to parse the substring
	123	* as a number in that base. On success, sets @result to the integer represented
	124	* by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
	125	*/
	126	static int match_number(substring_t s, int result, int base)
	127	{
	128	char *endp;
	129	char *buf;
	130	int ret;
	131
	132	buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
	133	if (!buf)
	134	return -ENOMEM;
	135	memcpy(buf, s->from, s->to - s->from);
	136	buf[s->to - s->from] = '\0';
	137	*result = simple_strtol(buf, &endp, base);
	138	ret = 0;
	139	if (endp == buf)
	140	ret = -EINVAL;
	141	kfree(buf);
	142	return ret;
	143	}
	144
	145	/**
	146	* match_int: - scan a decimal representation of an integer from a substring_t
	147	* @s: substring_t to be scanned
	148	* @result: resulting integer on success
	149	*
	150	* Description: Attempts to parse the &substring_t @s as a decimal integer. On
	151	* success, sets @result to the integer represented by the string and returns 0.
	152	* Returns either -ENOMEM or -EINVAL on failure.
	153	*/
	154	int match_int(substring_t s, int result)
	155	{
	156	return match_number(s, result, 0);
	157	}
	158
	159	/**
	160	* match_octal: - scan an octal representation of an integer from a substring_t
	161	* @s: substring_t to be scanned
	162	* @result: resulting integer on success
	163	*
	164	* Description: Attempts to parse the &substring_t @s as an octal integer. On
	165	* success, sets @result to the integer represented by the string and returns
	166	* 0. Returns either -ENOMEM or -EINVAL on failure.
	167	*/
	168	int match_octal(substring_t s, int result)
	169	{
	170	return match_number(s, result, 8);
	171	}
	172
173	/**
174	* match_hex: - scan a hex representation of an integer from a substring_t
175	* @s: substring_t to be scanned
176	* @result: resulting integer on success
177	*
178	* Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
179	* On success, sets @result to the integer represented by the string and
180	* returns 0. Returns either -ENOMEM or -EINVAL on failure.
181	*/
182	int match_hex(substring_t s, int result)
183	{
184	return match_number(s, result, 16);
185	}
186
187	/**
b32a09db MA	188	* match_strlcpy: - Copy the characters from a substring_t to a sized buffer
	189	* @dest: where to copy to
	190	* @src: &substring_t to copy
	191	* @size: size of destination buffer
1da177e4	192	*
b32a09db MA	193	* Description: Copy the characters in &substring_t @src to the
	194	* c-style string @dest. Copy no more than @size - 1 characters, plus
	195	* the terminating NUL. Return length of @src.
1da177e4	196	*/
b32a09db	197	size_t match_strlcpy(char dest, const substring_t src, size_t size)
1da177e4	198	{
b32a09db MA	199	size_t ret = src->to - src->from;
	200
	201	if (size) {
	202	size_t len = ret >= size ? size - 1 : ret;
	203	memcpy(dest, src->from, len);
	204	dest[len] = '\0';
	205	}
	206	return ret;
1da177e4 LT	207	}
	208
	209	/**
	210	* match_strdup: - allocate a new string with the contents of a substring_t
	211	* @s: &substring_t to copy
	212	*
	213	* Description: Allocates and returns a string filled with the contents of
	214	* the &substring_t @s. The caller is responsible for freeing the returned
	215	* string with kfree().
	216	*/
ef4533f8	217	char match_strdup(const substring_t s)
1da177e4	218	{
b32a09db MA	219	size_t sz = s->to - s->from + 1;
b32a09db MA	220	char *p = kmalloc(sz, GFP_KERNEL);
1da177e4	221	if (p)
b32a09db	222	match_strlcpy(p, s, sz);
1da177e4 LT	223	return p;
	224	}
	225
	226	EXPORT_SYMBOL(match_token);
	227	EXPORT_SYMBOL(match_int);
	228	EXPORT_SYMBOL(match_octal);
	229	EXPORT_SYMBOL(match_hex);
b32a09db	230	EXPORT_SYMBOL(match_strlcpy);
1da177e4	231	EXPORT_SYMBOL(match_strdup);