1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Filesystem parameter description and parser
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #ifndef _LINUX_FS_PARSER_H
9 #define _LINUX_FS_PARSER_H
11 #include <linux/fs_context.h>
15 struct constant_table {
21 * The type of parameter expected.
23 enum fs_parameter_type {
24 __fs_param_wasnt_defined,
28 fs_param_is_u32_octal,
38 nr__fs_parameter_type,
42 * Specification of the type of value a parameter wants.
44 * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
45 * should be used to generate elements of this type.
47 struct fs_parameter_spec {
49 u8 opt; /* Option number (returned by fs_parse()) */
50 enum fs_parameter_type type:8; /* The desired parameter type */
52 #define fs_param_v_optional 0x0001 /* The value is optional */
53 #define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */
54 #define fs_param_neg_with_empty 0x0004 /* "xxx=" is negative param */
55 #define fs_param_deprecated 0x0008 /* The param is deprecated */
59 struct fs_parameter_enum {
64 struct fs_parameter_description {
65 const char name[16]; /* Name for logging purposes */
66 const struct fs_parameter_spec *specs; /* List of param specifications */
72 struct fs_parse_result {
73 bool negated; /* T if param was "noxxx" */
75 bool boolean; /* For spec_bool */
76 int int_32; /* For spec_s32/spec_enum */
77 unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */
78 u64 uint_64; /* For spec_u64 */
82 extern int fs_parse(struct fs_context *fc,
83 const struct fs_parameter_description *desc,
84 struct fs_parameter *value,
85 struct fs_parse_result *result);
86 extern int fs_lookup_param(struct fs_context *fc,
87 struct fs_parameter *param,
91 extern int __lookup_constant(const struct constant_table tbl[], size_t tbl_size,
92 const char *name, int not_found);
93 #define lookup_constant(t, n, nf) __lookup_constant(t, ARRAY_SIZE(t), (n), (nf))
95 #ifdef CONFIG_VALIDATE_FS_PARSER
96 extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
97 int low, int high, int special);
98 extern bool fs_validate_description(const struct fs_parameter_description *desc);
100 static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
101 int low, int high, int special)
103 static inline bool fs_validate_description(const struct fs_parameter_description *desc)
108 * Parameter type, name, index and flags element constructors. Use as:
110 * fsparam_xxxx("foo", Opt_foo)
112 * If existing helpers are not enough, direct use of __fsparam() would
113 * work, but any such case is probably a sign that new helper is needed.
114 * Helpers will remain stable; low-level implementation may change.
116 #define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \
125 #define fsparam_flag(NAME, OPT) __fsparam(fs_param_is_flag, NAME, OPT, 0, NULL)
126 #define fsparam_flag_no(NAME, OPT) \
127 __fsparam(fs_param_is_flag, NAME, OPT, \
128 fs_param_neg_with_no, NULL)
129 #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL)
130 #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL)
131 #define fsparam_u32oct(NAME, OPT) \
132 __fsparam(fs_param_is_u32_octal, NAME, OPT, 0, NULL)
133 #define fsparam_u32hex(NAME, OPT) \
134 __fsparam(fs_param_is_u32_hex, NAME, OPT, 0, NULL)
135 #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL)
136 #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL)
137 #define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array)
138 #define fsparam_string(NAME, OPT) \
139 __fsparam(fs_param_is_string, NAME, OPT, 0, NULL)
140 #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL)
141 #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL)
142 #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL)
143 #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL)
146 #endif /* _LINUX_FS_PARSER_H */