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1 : /* SPDX-License-Identifier: GPL-2.0-or-later */
2 : /* Filesystem parameter description and parser
3 : *
4 : * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 : * Written by David Howells (dhowells@redhat.com)
6 : */
7 :
8 : #ifndef _LINUX_FS_PARSER_H
9 : #define _LINUX_FS_PARSER_H
10 :
11 : #include <linux/fs_context.h>
12 :
13 : struct path;
14 :
15 : struct constant_table {
16 : const char *name;
17 : int value;
18 : };
19 :
20 : struct fs_parameter_spec;
21 : struct fs_parse_result;
22 : typedef int fs_param_type(struct p_log *,
23 : const struct fs_parameter_spec *,
24 : struct fs_parameter *,
25 : struct fs_parse_result *);
26 : /*
27 : * The type of parameter expected.
28 : */
29 : fs_param_type fs_param_is_bool, fs_param_is_u32, fs_param_is_s32, fs_param_is_u64,
30 : fs_param_is_enum, fs_param_is_string, fs_param_is_blob, fs_param_is_blockdev,
31 : fs_param_is_path, fs_param_is_fd;
32 :
33 : /*
34 : * Specification of the type of value a parameter wants.
35 : *
36 : * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
37 : * should be used to generate elements of this type.
38 : */
39 : struct fs_parameter_spec {
40 : const char *name;
41 : fs_param_type *type; /* The desired parameter type */
42 : u8 opt; /* Option number (returned by fs_parse()) */
43 : unsigned short flags;
44 : #define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */
45 : #define fs_param_can_be_empty 0x0004 /* "xxx=" is allowed */
46 : #define fs_param_deprecated 0x0008 /* The param is deprecated */
47 : const void *data;
48 : };
49 :
50 : /*
51 : * Result of parse.
52 : */
53 : struct fs_parse_result {
54 : bool negated; /* T if param was "noxxx" */
55 : union {
56 : bool boolean; /* For spec_bool */
57 : int int_32; /* For spec_s32/spec_enum */
58 : unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */
59 : u64 uint_64; /* For spec_u64 */
60 : };
61 : };
62 :
63 : extern int __fs_parse(struct p_log *log,
64 : const struct fs_parameter_spec *desc,
65 : struct fs_parameter *value,
66 : struct fs_parse_result *result);
67 :
68 : static inline int fs_parse(struct fs_context *fc,
69 : const struct fs_parameter_spec *desc,
70 : struct fs_parameter *param,
71 : struct fs_parse_result *result)
72 : {
73 2 : return __fs_parse(&fc->log, desc, param, result);
74 : }
75 :
76 : extern int fs_lookup_param(struct fs_context *fc,
77 : struct fs_parameter *param,
78 : bool want_bdev,
79 : unsigned int flags,
80 : struct path *_path);
81 :
82 : extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found);
83 :
84 : #ifdef CONFIG_VALIDATE_FS_PARSER
85 : extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
86 : int low, int high, int special);
87 : extern bool fs_validate_description(const char *name,
88 : const struct fs_parameter_spec *desc);
89 : #else
90 : static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
91 : int low, int high, int special)
92 : { return true; }
93 : static inline bool fs_validate_description(const char *name,
94 : const struct fs_parameter_spec *desc)
95 : { return true; }
96 : #endif
97 :
98 : /*
99 : * Parameter type, name, index and flags element constructors. Use as:
100 : *
101 : * fsparam_xxxx("foo", Opt_foo)
102 : *
103 : * If existing helpers are not enough, direct use of __fsparam() would
104 : * work, but any such case is probably a sign that new helper is needed.
105 : * Helpers will remain stable; low-level implementation may change.
106 : */
107 : #define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \
108 : { \
109 : .name = NAME, \
110 : .opt = OPT, \
111 : .type = TYPE, \
112 : .flags = FLAGS, \
113 : .data = DATA \
114 : }
115 :
116 : #define fsparam_flag(NAME, OPT) __fsparam(NULL, NAME, OPT, 0, NULL)
117 : #define fsparam_flag_no(NAME, OPT) \
118 : __fsparam(NULL, NAME, OPT, fs_param_neg_with_no, NULL)
119 : #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL)
120 : #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL)
121 : #define fsparam_u32oct(NAME, OPT) \
122 : __fsparam(fs_param_is_u32, NAME, OPT, 0, (void *)8)
123 : #define fsparam_u32hex(NAME, OPT) \
124 : __fsparam(fs_param_is_u32_hex, NAME, OPT, 0, (void *)16)
125 : #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL)
126 : #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL)
127 : #define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array)
128 : #define fsparam_string(NAME, OPT) \
129 : __fsparam(fs_param_is_string, NAME, OPT, 0, NULL)
130 : #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL)
131 : #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL)
132 : #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL)
133 : #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL)
134 :
135 : #endif /* _LINUX_FS_PARSER_H */
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