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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Filesystem parameter description and parser
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _LINUX_FS_PARSER_H
#define _LINUX_FS_PARSER_H
#include <linux/fs_context.h>
struct path;
struct constant_table {
const char *name;
int value;
};
struct fs_parameter_spec;
struct fs_parse_result;
typedef int fs_param_type(struct p_log *,
const struct fs_parameter_spec *,
struct fs_parameter *,
struct fs_parse_result *);
/*
* The type of parameter expected.
*/
fs_param_type fs_param_is_bool, fs_param_is_u32, fs_param_is_s32, fs_param_is_u64,
fs_param_is_enum, fs_param_is_string, fs_param_is_blob, fs_param_is_blockdev,
fs_param_is_path, fs_param_is_fd, fs_param_is_uid, fs_param_is_gid;
/*
* Specification of the type of value a parameter wants.
*
* Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
* should be used to generate elements of this type.
*/
struct fs_parameter_spec {
const char *name;
fs_param_type *type; /* The desired parameter type */
u8 opt; /* Option number (returned by fs_parse()) */
unsigned short flags;
#define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */
#define fs_param_can_be_empty 0x0004 /* "xxx=" is allowed */
#define fs_param_deprecated 0x0008 /* The param is deprecated */
const void *data;
};
/*
* Result of parse.
*/
struct fs_parse_result {
bool negated; /* T if param was "noxxx" */
union {
bool boolean; /* For spec_bool */
int int_32; /* For spec_s32/spec_enum */
unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */
u64 uint_64; /* For spec_u64 */
kuid_t uid;
kgid_t gid;
};
};
extern int __fs_parse(struct p_log *log,
const struct fs_parameter_spec *desc,
struct fs_parameter *value,
struct fs_parse_result *result);
static inline int fs_parse(struct fs_context *fc,
const struct fs_parameter_spec *desc,
struct fs_parameter *param,
struct fs_parse_result *result)
{
return __fs_parse(&fc->log, desc, param, result);
}
extern int fs_lookup_param(struct fs_context *fc,
struct fs_parameter *param,
bool want_bdev,
unsigned int flags,
struct path *_path);
extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found);
#ifdef CONFIG_VALIDATE_FS_PARSER
extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special);
extern bool fs_validate_description(const char *name,
const struct fs_parameter_spec *desc);
#else
static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special)
{ return true; }
static inline bool fs_validate_description(const char *name,
const struct fs_parameter_spec *desc)
{ return true; }
#endif
/*
* Parameter type, name, index and flags element constructors. Use as:
*
* fsparam_xxxx("foo", Opt_foo)
*
* If existing helpers are not enough, direct use of __fsparam() would
* work, but any such case is probably a sign that new helper is needed.
* Helpers will remain stable; low-level implementation may change.
*/
#define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \
{ \
.name = NAME, \
.opt = OPT, \
.type = TYPE, \
.flags = FLAGS, \
.data = DATA \
}
#define fsparam_flag(NAME, OPT) __fsparam(NULL, NAME, OPT, 0, NULL)
#define fsparam_flag_no(NAME, OPT) \
__fsparam(NULL, NAME, OPT, fs_param_neg_with_no, NULL)
#define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL)
#define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL)
#define fsparam_u32oct(NAME, OPT) \
__fsparam(fs_param_is_u32, NAME, OPT, 0, (void *)8)
#define fsparam_u32hex(NAME, OPT) \
__fsparam(fs_param_is_u32_hex, NAME, OPT, 0, (void *)16)
#define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL)
#define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL)
#define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array)
#define fsparam_string(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, 0, NULL)
#define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL)
#define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL)
#define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL)
#define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL)
#define fsparam_uid(NAME, OPT) __fsparam(fs_param_is_uid, NAME, OPT, 0, NULL)
#define fsparam_gid(NAME, OPT) __fsparam(fs_param_is_gid, NAME, OPT, 0, NULL)
/* String parameter that allows empty argument */
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
#endif /* _LINUX_FS_PARSER_H */
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