[people/ms/linux.git] / fs / fs_parser.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Filesystem parameter parser.
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/export.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/namei.h>
#include "internal.h"

static const struct constant_table bool_names[] = {
	{ "0",		false },
	{ "1",		true },
	{ "false",	false },
	{ "no",		false },
	{ "true",	true },
	{ "yes",	true },
	{ },
};

static const struct constant_table *
__lookup_constant(const struct constant_table *tbl, const char *name)
{
	for ( ; tbl->name; tbl++)
		if (strcmp(name, tbl->name) == 0)
			return tbl;
	return NULL;
}

/**
 * lookup_constant - Look up a constant by name in an ordered table
 * @tbl: The table of constants to search.
 * @name: The name to look up.
 * @not_found: The value to return if the name is not found.
 */
int lookup_constant(const struct constant_table *tbl, const char *name, int not_found)
{
	const struct constant_table *p = __lookup_constant(tbl, name);

	return p ? p->value : not_found;
}
EXPORT_SYMBOL(lookup_constant);

static inline bool is_flag(const struct fs_parameter_spec *p)
{
	return p->type == NULL;
}

static const struct fs_parameter_spec *fs_lookup_key(
	const struct fs_parameter_spec *desc,
	struct fs_parameter *param, bool *negated)
{
	const struct fs_parameter_spec *p, *other = NULL;
	const char *name = param->key;
	bool want_flag = param->type == fs_value_is_flag;

	*negated = false;
	for (p = desc; p->name; p++) {
		if (strcmp(p->name, name) != 0)
			continue;
		if (likely(is_flag(p) == want_flag))
			return p;
		other = p;
	}
	if (want_flag) {
		if (name[0] == 'n' && name[1] == 'o' && name[2]) {
			for (p = desc; p->name; p++) {
				if (strcmp(p->name, name + 2) != 0)
					continue;
				if (!(p->flags & fs_param_neg_with_no))
					continue;
				*negated = true;
				return p;
			}
		}
	}
	return other;
}

/*
 * fs_parse - Parse a filesystem configuration parameter
 * @fc: The filesystem context to log errors through.
 * @desc: The parameter description to use.
 * @param: The parameter.
 * @result: Where to place the result of the parse
 *
 * Parse a filesystem configuration parameter and attempt a conversion for a
 * simple parameter for which this is requested.  If successful, the determined
 * parameter ID is placed into @result->key, the desired type is indicated in
 * @result->t and any converted value is placed into an appropriate member of
 * the union in @result.
 *
 * The function returns the parameter number if the parameter was matched,
 * -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
 * unknown parameters are okay and -EINVAL if there was a conversion issue or
 * the parameter wasn't recognised and unknowns aren't okay.
 */
int __fs_parse(struct p_log *log,
	     const struct fs_parameter_spec *desc,
	     struct fs_parameter *param,
	     struct fs_parse_result *result)
{
	const struct fs_parameter_spec *p;

	result->uint_64 = 0;

	p = fs_lookup_key(desc, param, &result->negated);
	if (!p)
		return -ENOPARAM;

	if (p->flags & fs_param_deprecated)
		warn_plog(log, "Deprecated parameter '%s'", param->key);

	/* Try to turn the type we were given into the type desired by the
	 * parameter and give an error if we can't.
	 */
	if (is_flag(p)) {
		if (param->type != fs_value_is_flag)
			return inval_plog(log, "Unexpected value for '%s'",
				      param->key);
		result->boolean = !result->negated;
	} else  {
		int ret = p->type(log, p, param, result);
		if (ret)
			return ret;
	}
	return p->opt;
}
EXPORT_SYMBOL(__fs_parse);

/**
 * fs_lookup_param - Look up a path referred to by a parameter
 * @fc: The filesystem context to log errors through.
 * @param: The parameter.
 * @want_bdev: T if want a blockdev
 * @_path: The result of the lookup
 */
int fs_lookup_param(struct fs_context *fc,
		    struct fs_parameter *param,
		    bool want_bdev,
		    struct path *_path)
{
	struct filename *f;
	unsigned int flags = 0;
	bool put_f;
	int ret;

	switch (param->type) {
	case fs_value_is_string:
		f = getname_kernel(param->string);
		if (IS_ERR(f))
			return PTR_ERR(f);
		put_f = true;
		break;
	case fs_value_is_filename:
		f = param->name;
		put_f = false;
		break;
	default:
		return invalf(fc, "%s: not usable as path", param->key);
	}

	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
	if (ret < 0) {
		errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
		goto out;
	}

	if (want_bdev &&
	    !S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
		path_put(_path);
		_path->dentry = NULL;
		_path->mnt = NULL;
		errorf(fc, "%s: Non-blockdev passed as '%s'",
		       param->key, f->name);
		ret = -ENOTBLK;
	}

out:
	if (put_f)
		putname(f);
	return ret;
}
EXPORT_SYMBOL(fs_lookup_param);

static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param)
{
	return inval_plog(log, "Bad value for '%s'", param->key);
}

int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p,
		     struct fs_parameter *param, struct fs_parse_result *result)
{
	int b;
	if (param->type != fs_value_is_string)
		return fs_param_bad_value(log, param);
	if (!*param->string && (p->flags & fs_param_can_be_empty))
		return 0;
	b = lookup_constant(bool_names, param->string, -1);
	if (b == -1)
		return fs_param_bad_value(log, param);
	result->boolean = b;
	return 0;
}
EXPORT_SYMBOL(fs_param_is_bool);

int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p,
		    struct fs_parameter *param, struct fs_parse_result *result)
{
	int base = (unsigned long)p->data;
	if (param->type != fs_value_is_string)
		return fs_param_bad_value(log, param);
	if (!*param->string && (p->flags & fs_param_can_be_empty))
		return 0;
	if (kstrtouint(param->string, base, &result->uint_32) < 0)
		return fs_param_bad_value(log, param);
	return 0;
}
EXPORT_SYMBOL(fs_param_is_u32);

int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p,
		    struct fs_parameter *param, struct fs_parse_result *result)
{
	if (param->type != fs_value_is_string)
		return fs_param_bad_value(log, param);
	if (!*param->string && (p->flags & fs_param_can_be_empty))
		return 0;
	if (kstrtoint(param->string, 0, &result->int_32) < 0)
		return fs_param_bad_value(log, param);
	return 0;
}
EXPORT_SYMBOL(fs_param_is_s32);

int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p,
		    struct fs_parameter *param, struct fs_parse_result *result)
{
	if (param->type != fs_value_is_string)
		return fs_param_bad_value(log, param);
	if (!*param->string && (p->flags & fs_param_can_be_empty))
		return 0;
	if (kstrtoull(param->string, 0, &result->uint_64) < 0)
		return fs_param_bad_value(log, param);
	return 0;
}
EXPORT_SYMBOL(fs_param_is_u64);

int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p,
		     struct fs_parameter *param, struct fs_parse_result *result)
{
	const struct constant_table *c;
	if (param->type != fs_value_is_string)
		return fs_param_bad_value(log, param);
	if (!*param->string && (p->flags & fs_param_can_be_empty))
		return 0;
	c = __lookup_constant(p->data, param->string);
	if (!c)
		return fs_param_bad_value(log, param);
	result->uint_32 = c->value;
	return 0;
}
EXPORT_SYMBOL(fs_param_is_enum);

int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p,
		       struct fs_parameter *param, struct fs_parse_result *result)
{
	if (param->type != fs_value_is_string ||
	    (!*param->string && !(p->flags & fs_param_can_be_empty)))
		return fs_param_bad_value(log, param);
	return 0;
}
EXPORT_SYMBOL(fs_param_is_string);

int fs_param_is_blob(struct p_log *log, const struct fs_parameter_spec *p,
		     struct fs_parameter *param, struct fs_parse_result *result)
{
	if (param->type != fs_value_is_blob)
		return fs_param_bad_value(log, param);
	return 0;
}
EXPORT_SYMBOL(fs_param_is_blob);

int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p,
		  struct fs_parameter *param, struct fs_parse_result *result)
{
	switch (param->type) {
	case fs_value_is_string:
		if ((!*param->string && !(p->flags & fs_param_can_be_empty)) ||
		    kstrtouint(param->string, 0, &result->uint_32) < 0)
			break;
		if (result->uint_32 <= INT_MAX)
			return 0;
		break;
	case fs_value_is_file:
		result->uint_32 = param->dirfd;
		if (result->uint_32 <= INT_MAX)
			return 0;
		break;
	default:
		break;
	}
	return fs_param_bad_value(log, param);
}
EXPORT_SYMBOL(fs_param_is_fd);

int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p,
		  struct fs_parameter *param, struct fs_parse_result *result)
{
	return 0;
}
EXPORT_SYMBOL(fs_param_is_blockdev);

int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p,
		     struct fs_parameter *param, struct fs_parse_result *result)
{
	return 0;
}
EXPORT_SYMBOL(fs_param_is_path);

#ifdef CONFIG_VALIDATE_FS_PARSER
/**
 * validate_constant_table - Validate a constant table
 * @tbl: The constant table to validate.
 * @tbl_size: The size of the table.
 * @low: The lowest permissible value.
 * @high: The highest permissible value.
 * @special: One special permissible value outside of the range.
 */
bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
			     int low, int high, int special)
{
	size_t i;
	bool good = true;

	if (tbl_size == 0) {
		pr_warn("VALIDATE C-TBL: Empty\n");
		return true;
	}

	for (i = 0; i < tbl_size; i++) {
		if (!tbl[i].name) {
			pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
			good = false;
		} else if (i > 0 && tbl[i - 1].name) {
			int c = strcmp(tbl[i-1].name, tbl[i].name);

			if (c == 0) {
				pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",
				       i, tbl[i].name);
				good = false;
			}
			if (c > 0) {
				pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
				       i, tbl[i-1].name, tbl[i].name);
				good = false;
			}
		}

		if (tbl[i].value != special &&
		    (tbl[i].value < low || tbl[i].value > high)) {
			pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
			       i, tbl[i].name, tbl[i].value, low, high);
			good = false;
		}
	}

	return good;
}

/**
 * fs_validate_description - Validate a parameter description
 * @name: The parameter name to search for.
 * @desc: The parameter description to validate.
 */
bool fs_validate_description(const char *name,
	const struct fs_parameter_spec *desc)
{
	const struct fs_parameter_spec *param, *p2;
	bool good = true;

	for (param = desc; param->name; param++) {
		/* Check for duplicate parameter names */
		for (p2 = desc; p2 < param; p2++) {
			if (strcmp(param->name, p2->name) == 0) {
				if (is_flag(param) != is_flag(p2))
					continue;
				pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
				       name, param->name);
				good = false;
			}
		}
	}
	return good;
}
#endif /* CONFIG_VALIDATE_FS_PARSER */
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
31d921c7 DH	2	/* Filesystem parameter parser.
	3	*
	4	* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
31d921c7 DH	6	*/
	7
	8	#include <linux/export.h>
	9	#include <linux/fs_context.h>
	10	#include <linux/fs_parser.h>
	11	#include <linux/slab.h>
	12	#include <linux/security.h>
	13	#include <linux/namei.h>
	14	#include "internal.h"
	15
	16	static const struct constant_table bool_names[] = {
	17	{ "0", false },
	18	{ "1", true },
	19	{ "false", false },
	20	{ "no", false },
	21	{ "true", true },
	22	{ "yes", true },
34264ae3	23	{ },
31d921c7 DH	24	};
31d921c7 DH	25
34264ae3 AV	26	static const struct constant_table *
	27	__lookup_constant(const struct constant_table tbl, const char name)
	28	{
	29	for ( ; tbl->name; tbl++)
	30	if (strcmp(name, tbl->name) == 0)
	31	return tbl;
	32	return NULL;
	33	}
	34
31d921c7 DH	35	/**
	36	* lookup_constant - Look up a constant by name in an ordered table
	37	* @tbl: The table of constants to search.
31d921c7 DH	38	* @name: The name to look up.
	39	* @not_found: The value to return if the name is not found.
	40	*/
34264ae3	41	int lookup_constant(const struct constant_table tbl, const char name, int not_found)
31d921c7	42	{
34264ae3	43	const struct constant_table *p = __lookup_constant(tbl, name);
31d921c7	44
34264ae3	45	return p ? p->value : not_found;
31d921c7	46	}
34264ae3	47	EXPORT_SYMBOL(lookup_constant);
31d921c7	48
48ce73b1 AV	49	static inline bool is_flag(const struct fs_parameter_spec *p)
48ce73b1 AV	50	{
328de528	51	return p->type == NULL;
48ce73b1 AV	52	}
48ce73b1 AV	53
31d921c7	54	static const struct fs_parameter_spec *fs_lookup_key(
d7167b14	55	const struct fs_parameter_spec *desc,
48ce73b1	56	struct fs_parameter param, bool negated)
31d921c7	57	{
48ce73b1 AV	58	const struct fs_parameter_spec p, other = NULL;
	59	const char *name = param->key;
	60	bool want_flag = param->type == fs_value_is_flag;
	61
	62	*negated = false;
	63	for (p = desc; p->name; p++) {
	64	if (strcmp(p->name, name) != 0)
	65	continue;
	66	if (likely(is_flag(p) == want_flag))
31d921c7	67	return p;
48ce73b1 AV	68	other = p;
	69	}
	70	if (want_flag) {
	71	if (name[0] == 'n' && name[1] == 'o' && name[2]) {
	72	for (p = desc; p->name; p++) {
	73	if (strcmp(p->name, name + 2) != 0)
	74	continue;
	75	if (!(p->flags & fs_param_neg_with_no))
	76	continue;
	77	*negated = true;
	78	return p;
	79	}
	80	}
	81	}
	82	return other;
31d921c7 DH	83	}
	84
	85	/*
	86	* fs_parse - Parse a filesystem configuration parameter
	87	* @fc: The filesystem context to log errors through.
	88	* @desc: The parameter description to use.
	89	* @param: The parameter.
	90	* @result: Where to place the result of the parse
	91	*
	92	* Parse a filesystem configuration parameter and attempt a conversion for a
	93	* simple parameter for which this is requested. If successful, the determined
	94	* parameter ID is placed into @result->key, the desired type is indicated in
	95	* @result->t and any converted value is placed into an appropriate member of
	96	* the union in @result.
	97	*
	98	* The function returns the parameter number if the parameter was matched,
	99	* -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
	100	* unknown parameters are okay and -EINVAL if there was a conversion issue or
	101	* the parameter wasn't recognised and unknowns aren't okay.
	102	*/
7f5d3814	103	int __fs_parse(struct p_log *log,
d7167b14	104	const struct fs_parameter_spec *desc,
31d921c7 DH	105	struct fs_parameter *param,
	106	struct fs_parse_result *result)
	107	{
	108	const struct fs_parameter_spec *p;
31d921c7	109
31d921c7 DH	110	result->uint_64 = 0;
31d921c7 DH	111
48ce73b1 AV	112	p = fs_lookup_key(desc, param, &result->negated);
	113	if (!p)
	114	return -ENOPARAM;
31d921c7 DH	115
31d921c7 DH	116	if (p->flags & fs_param_deprecated)
7f5d3814	117	warn_plog(log, "Deprecated parameter '%s'", param->key);
31d921c7	118
31d921c7 DH	119	/* Try to turn the type we were given into the type desired by the
	120	* parameter and give an error if we can't.
	121	*/
328de528	122	if (is_flag(p)) {
0f89589a	123	if (param->type != fs_value_is_flag)
7f5d3814 AV	124	return inval_plog(log, "Unexpected value for '%s'",
7f5d3814 AV	125	param->key);
48ce73b1	126	result->boolean = !result->negated;
328de528 AV	127	} else {
	128	int ret = p->type(log, p, param, result);
	129	if (ret)
	130	return ret;
31d921c7	131	}
31d921c7	132	return p->opt;
31d921c7	133	}
7f5d3814 AV	134	EXPORT_SYMBOL(__fs_parse);
7f5d3814 AV	135
31d921c7 DH	136	/**
	137	* fs_lookup_param - Look up a path referred to by a parameter
	138	* @fc: The filesystem context to log errors through.
	139	* @param: The parameter.
	140	* @want_bdev: T if want a blockdev
	141	* @_path: The result of the lookup
	142	*/
	143	int fs_lookup_param(struct fs_context *fc,
	144	struct fs_parameter *param,
	145	bool want_bdev,
	146	struct path *_path)
	147	{
	148	struct filename *f;
	149	unsigned int flags = 0;
	150	bool put_f;
	151	int ret;
	152
	153	switch (param->type) {
	154	case fs_value_is_string:
	155	f = getname_kernel(param->string);
	156	if (IS_ERR(f))
	157	return PTR_ERR(f);
	158	put_f = true;
	159	break;
31d921c7 DH	160	case fs_value_is_filename:
	161	f = param->name;
	162	put_f = false;
	163	break;
	164	default:
	165	return invalf(fc, "%s: not usable as path", param->key);
	166	}
	167
	168	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
	169	if (ret < 0) {
	170	errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
	171	goto out;
	172	}
	173
	174	if (want_bdev &&
	175	!S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
	176	path_put(_path);
	177	_path->dentry = NULL;
	178	_path->mnt = NULL;
	179	errorf(fc, "%s: Non-blockdev passed as '%s'",
	180	param->key, f->name);
	181	ret = -ENOTBLK;
	182	}
	183
	184	out:
	185	if (put_f)
	186	putname(f);
	187	return ret;
	188	}
	189	EXPORT_SYMBOL(fs_lookup_param);
	190
97383c74	191	static int fs_param_bad_value(struct p_log log, struct fs_parameter param)
328de528 AV	192	{
	193	return inval_plog(log, "Bad value for '%s'", param->key);
	194	}
	195
	196	int fs_param_is_bool(struct p_log log, const struct fs_parameter_spec p,
	197	struct fs_parameter param, struct fs_parse_result result)
	198	{
	199	int b;
	200	if (param->type != fs_value_is_string)
	201	return fs_param_bad_value(log, param);
6abfaaf1 LC	202	if (!*param->string && (p->flags & fs_param_can_be_empty))
6abfaaf1 LC	203	return 0;
328de528 AV	204	b = lookup_constant(bool_names, param->string, -1);
	205	if (b == -1)
	206	return fs_param_bad_value(log, param);
	207	result->boolean = b;
	208	return 0;
	209	}
	210	EXPORT_SYMBOL(fs_param_is_bool);
	211
	212	int fs_param_is_u32(struct p_log log, const struct fs_parameter_spec p,
	213	struct fs_parameter param, struct fs_parse_result result)
	214	{
	215	int base = (unsigned long)p->data;
6abfaaf1 LC	216	if (param->type != fs_value_is_string)
	217	return fs_param_bad_value(log, param);
	218	if (!*param->string && (p->flags & fs_param_can_be_empty))
	219	return 0;
	220	if (kstrtouint(param->string, base, &result->uint_32) < 0)
328de528 AV	221	return fs_param_bad_value(log, param);
	222	return 0;
	223	}
	224	EXPORT_SYMBOL(fs_param_is_u32);
	225
	226	int fs_param_is_s32(struct p_log log, const struct fs_parameter_spec p,
	227	struct fs_parameter param, struct fs_parse_result result)
	228	{
6abfaaf1 LC	229	if (param->type != fs_value_is_string)
	230	return fs_param_bad_value(log, param);
	231	if (!*param->string && (p->flags & fs_param_can_be_empty))
	232	return 0;
	233	if (kstrtoint(param->string, 0, &result->int_32) < 0)
328de528 AV	234	return fs_param_bad_value(log, param);
	235	return 0;
	236	}
	237	EXPORT_SYMBOL(fs_param_is_s32);
	238
	239	int fs_param_is_u64(struct p_log log, const struct fs_parameter_spec p,
	240	struct fs_parameter param, struct fs_parse_result result)
	241	{
6abfaaf1 LC	242	if (param->type != fs_value_is_string)
	243	return fs_param_bad_value(log, param);
	244	if (!*param->string && (p->flags & fs_param_can_be_empty))
	245	return 0;
	246	if (kstrtoull(param->string, 0, &result->uint_64) < 0)
328de528 AV	247	return fs_param_bad_value(log, param);
	248	return 0;
	249	}
	250	EXPORT_SYMBOL(fs_param_is_u64);
	251
	252	int fs_param_is_enum(struct p_log log, const struct fs_parameter_spec p,
	253	struct fs_parameter param, struct fs_parse_result result)
	254	{
	255	const struct constant_table *c;
	256	if (param->type != fs_value_is_string)
	257	return fs_param_bad_value(log, param);
6abfaaf1 LC	258	if (!*param->string && (p->flags & fs_param_can_be_empty))
6abfaaf1 LC	259	return 0;
328de528 AV	260	c = __lookup_constant(p->data, param->string);
	261	if (!c)
	262	return fs_param_bad_value(log, param);
	263	result->uint_32 = c->value;
	264	return 0;
	265	}
	266	EXPORT_SYMBOL(fs_param_is_enum);
	267
	268	int fs_param_is_string(struct p_log log, const struct fs_parameter_spec p,
	269	struct fs_parameter param, struct fs_parse_result result)
	270	{
6abfaaf1 LC	271	if (param->type != fs_value_is_string \|\|
6abfaaf1 LC	272	(!*param->string && !(p->flags & fs_param_can_be_empty)))
328de528 AV	273	return fs_param_bad_value(log, param);
	274	return 0;
	275	}
	276	EXPORT_SYMBOL(fs_param_is_string);
	277
	278	int fs_param_is_blob(struct p_log log, const struct fs_parameter_spec p,
	279	struct fs_parameter param, struct fs_parse_result result)
	280	{
	281	if (param->type != fs_value_is_blob)
	282	return fs_param_bad_value(log, param);
	283	return 0;
	284	}
	285	EXPORT_SYMBOL(fs_param_is_blob);
	286
	287	int fs_param_is_fd(struct p_log log, const struct fs_parameter_spec p,
	288	struct fs_parameter param, struct fs_parse_result result)
	289	{
	290	switch (param->type) {
	291	case fs_value_is_string:
6abfaaf1 LC	292	if ((!*param->string && !(p->flags & fs_param_can_be_empty)) \|\|
6abfaaf1 LC	293	kstrtouint(param->string, 0, &result->uint_32) < 0)
328de528 AV	294	break;
	295	if (result->uint_32 <= INT_MAX)
	296	return 0;
	297	break;
	298	case fs_value_is_file:
	299	result->uint_32 = param->dirfd;
	300	if (result->uint_32 <= INT_MAX)
	301	return 0;
	302	break;
	303	default:
	304	break;
	305	}
	306	return fs_param_bad_value(log, param);
	307	}
	308	EXPORT_SYMBOL(fs_param_is_fd);
	309
	310	int fs_param_is_blockdev(struct p_log log, const struct fs_parameter_spec p,
	311	struct fs_parameter param, struct fs_parse_result result)
	312	{
	313	return 0;
	314	}
	315	EXPORT_SYMBOL(fs_param_is_blockdev);
	316
	317	int fs_param_is_path(struct p_log log, const struct fs_parameter_spec p,
	318	struct fs_parameter param, struct fs_parse_result result)
	319	{
	320	return 0;
	321	}
	322	EXPORT_SYMBOL(fs_param_is_path);
	323
31d921c7 DH	324	#ifdef CONFIG_VALIDATE_FS_PARSER
	325	/**
	326	* validate_constant_table - Validate a constant table
31d921c7 DH	327	* @tbl: The constant table to validate.
	328	* @tbl_size: The size of the table.
	329	* @low: The lowest permissible value.
	330	* @high: The highest permissible value.
	331	* @special: One special permissible value outside of the range.
	332	*/
	333	bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
	334	int low, int high, int special)
	335	{
	336	size_t i;
	337	bool good = true;
	338
	339	if (tbl_size == 0) {
	340	pr_warn("VALIDATE C-TBL: Empty\n");
	341	return true;
	342	}
	343
	344	for (i = 0; i < tbl_size; i++) {
	345	if (!tbl[i].name) {
	346	pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
	347	good = false;
	348	} else if (i > 0 && tbl[i - 1].name) {
	349	int c = strcmp(tbl[i-1].name, tbl[i].name);
	350
	351	if (c == 0) {
	352	pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",
	353	i, tbl[i].name);
	354	good = false;
	355	}
	356	if (c > 0) {
	357	pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
	358	i, tbl[i-1].name, tbl[i].name);
	359	good = false;
	360	}
	361	}
	362
	363	if (tbl[i].value != special &&
	364	(tbl[i].value < low \|\| tbl[i].value > high)) {
	365	pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
	366	i, tbl[i].name, tbl[i].value, low, high);
	367	good = false;
	368	}
	369	}
	370
	371	return good;
	372	}
	373
	374	/**
	375	* fs_validate_description - Validate a parameter description
21ae3ad1	376	* @name: The parameter name to search for.
31d921c7 DH	377	* @desc: The parameter description to validate.
31d921c7 DH	378	*/
96cafb9c	379	bool fs_validate_description(const char *name,
d7167b14	380	const struct fs_parameter_spec *desc)
31d921c7 DH	381	{
31d921c7 DH	382	const struct fs_parameter_spec param, p2;
2710c957	383	bool good = true;
31d921c7	384
d7167b14	385	for (param = desc; param->name; param++) {
d7167b14 AV	386	/* Check for duplicate parameter names */
	387	for (p2 = desc; p2 < param; p2++) {
	388	if (strcmp(param->name, p2->name) == 0) {
48ce73b1 AV	389	if (is_flag(param) != is_flag(p2))
48ce73b1 AV	390	continue;
d7167b14 AV	391	pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
	392	name, param->name);
	393	good = false;
31d921c7 DH	394	}
31d921c7 DH	395	}
31d921c7	396	}
31d921c7 DH	397	return good;
	398	}
	399	#endif /* CONFIG_VALIDATE_FS_PARSER */