David Howells | 31d921c | 2018-11-01 23:07:24 +0000 | [diff] [blame] | 1 | /* Filesystem parameter description and parser |
| 2 | * |
| 3 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #ifndef _LINUX_FS_PARSER_H |
| 13 | #define _LINUX_FS_PARSER_H |
| 14 | |
| 15 | #include <linux/fs_context.h> |
| 16 | |
| 17 | struct path; |
| 18 | |
| 19 | struct constant_table { |
| 20 | const char *name; |
| 21 | int value; |
| 22 | }; |
| 23 | |
| 24 | /* |
| 25 | * The type of parameter expected. |
| 26 | */ |
| 27 | enum fs_parameter_type { |
| 28 | __fs_param_wasnt_defined, |
| 29 | fs_param_is_flag, |
| 30 | fs_param_is_bool, |
| 31 | fs_param_is_u32, |
| 32 | fs_param_is_u32_octal, |
| 33 | fs_param_is_u32_hex, |
| 34 | fs_param_is_s32, |
| 35 | fs_param_is_u64, |
| 36 | fs_param_is_enum, |
| 37 | fs_param_is_string, |
| 38 | fs_param_is_blob, |
| 39 | fs_param_is_blockdev, |
| 40 | fs_param_is_path, |
| 41 | fs_param_is_fd, |
| 42 | nr__fs_parameter_type, |
| 43 | }; |
| 44 | |
| 45 | /* |
| 46 | * Specification of the type of value a parameter wants. |
| 47 | * |
| 48 | * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros |
| 49 | * should be used to generate elements of this type. |
| 50 | */ |
| 51 | struct fs_parameter_spec { |
| 52 | const char *name; |
| 53 | u8 opt; /* Option number (returned by fs_parse()) */ |
| 54 | enum fs_parameter_type type:8; /* The desired parameter type */ |
| 55 | unsigned short flags; |
| 56 | #define fs_param_v_optional 0x0001 /* The value is optional */ |
| 57 | #define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */ |
| 58 | #define fs_param_neg_with_empty 0x0004 /* "xxx=" is negative param */ |
| 59 | #define fs_param_deprecated 0x0008 /* The param is deprecated */ |
| 60 | }; |
| 61 | |
| 62 | struct fs_parameter_enum { |
| 63 | u8 opt; /* Option number (as fs_parameter_spec::opt) */ |
| 64 | char name[14]; |
| 65 | u8 value; |
| 66 | }; |
| 67 | |
| 68 | struct fs_parameter_description { |
| 69 | const char name[16]; /* Name for logging purposes */ |
| 70 | const struct fs_parameter_spec *specs; /* List of param specifications */ |
| 71 | const struct fs_parameter_enum *enums; /* Enum values */ |
| 72 | }; |
| 73 | |
| 74 | /* |
| 75 | * Result of parse. |
| 76 | */ |
| 77 | struct fs_parse_result { |
| 78 | bool negated; /* T if param was "noxxx" */ |
| 79 | bool has_value; /* T if value supplied to param */ |
| 80 | union { |
| 81 | bool boolean; /* For spec_bool */ |
| 82 | int int_32; /* For spec_s32/spec_enum */ |
| 83 | unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */ |
| 84 | u64 uint_64; /* For spec_u64 */ |
| 85 | }; |
| 86 | }; |
| 87 | |
| 88 | extern int fs_parse(struct fs_context *fc, |
| 89 | const struct fs_parameter_description *desc, |
| 90 | struct fs_parameter *value, |
| 91 | struct fs_parse_result *result); |
| 92 | extern int fs_lookup_param(struct fs_context *fc, |
| 93 | struct fs_parameter *param, |
| 94 | bool want_bdev, |
| 95 | struct path *_path); |
| 96 | |
| 97 | extern int __lookup_constant(const struct constant_table tbl[], size_t tbl_size, |
| 98 | const char *name, int not_found); |
| 99 | #define lookup_constant(t, n, nf) __lookup_constant(t, ARRAY_SIZE(t), (n), (nf)) |
| 100 | |
| 101 | #ifdef CONFIG_VALIDATE_FS_PARSER |
| 102 | extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, |
| 103 | int low, int high, int special); |
| 104 | extern bool fs_validate_description(const struct fs_parameter_description *desc); |
| 105 | #else |
| 106 | static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, |
| 107 | int low, int high, int special) |
| 108 | { return true; } |
| 109 | static inline bool fs_validate_description(const struct fs_parameter_description *desc) |
| 110 | { return true; } |
| 111 | #endif |
| 112 | |
| 113 | /* |
| 114 | * Parameter type, name, index and flags element constructors. Use as: |
| 115 | * |
| 116 | * fsparam_xxxx("foo", Opt_foo) |
| 117 | * |
| 118 | * If existing helpers are not enough, direct use of __fsparam() would |
| 119 | * work, but any such case is probably a sign that new helper is needed. |
| 120 | * Helpers will remain stable; low-level implementation may change. |
| 121 | */ |
| 122 | #define __fsparam(TYPE, NAME, OPT, FLAGS) \ |
| 123 | { \ |
| 124 | .name = NAME, \ |
| 125 | .opt = OPT, \ |
| 126 | .type = TYPE, \ |
| 127 | .flags = FLAGS \ |
| 128 | } |
| 129 | |
| 130 | #define fsparam_flag(NAME, OPT) __fsparam(fs_param_is_flag, NAME, OPT, 0) |
| 131 | #define fsparam_flag_no(NAME, OPT) \ |
| 132 | __fsparam(fs_param_is_flag, NAME, OPT, \ |
| 133 | fs_param_neg_with_no) |
| 134 | #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0) |
| 135 | #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0) |
| 136 | #define fsparam_u32oct(NAME, OPT) \ |
| 137 | __fsparam(fs_param_is_u32_octal, NAME, OPT, 0) |
| 138 | #define fsparam_u32hex(NAME, OPT) \ |
| 139 | __fsparam(fs_param_is_u32_hex, NAME, OPT, 0) |
| 140 | #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0) |
| 141 | #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0) |
| 142 | #define fsparam_enum(NAME, OPT) __fsparam(fs_param_is_enum, NAME, OPT, 0) |
| 143 | #define fsparam_string(NAME, OPT) \ |
| 144 | __fsparam(fs_param_is_string, NAME, OPT, 0) |
| 145 | #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0) |
| 146 | #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0) |
| 147 | #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0) |
| 148 | #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0) |
| 149 | |
| 150 | |
| 151 | #endif /* _LINUX_FS_PARSER_H */ |