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 ([email protected]) 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 /* 21 * The type of parameter expected. 22 */ 23 enum fs_parameter_type { 24 __fs_param_wasnt_defined, 25 fs_param_is_flag, 26 fs_param_is_bool, 27 fs_param_is_u32, 28 fs_param_is_u32_octal, 29 fs_param_is_u32_hex, 30 fs_param_is_s32, 31 fs_param_is_u64, 32 fs_param_is_enum, 33 fs_param_is_string, 34 fs_param_is_blob, 35 fs_param_is_blockdev, 36 fs_param_is_path, 37 fs_param_is_fd, 38 nr__fs_parameter_type, 39 }; 40 41 /* 42 * Specification of the type of value a parameter wants. 43 * 44 * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros 45 * should be used to generate elements of this type. 46 */ 47 struct fs_parameter_spec { 48 const char *name; 49 u8 opt; /* Option number (returned by fs_parse()) */ 50 enum fs_parameter_type type:8; /* The desired parameter type */ 51 unsigned short flags; 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 */ 56 const void *data; 57 }; 58 59 struct fs_parameter_description { 60 const char name[16]; /* Name for logging purposes */ 61 const struct fs_parameter_spec *specs; /* List of param specifications */ 62 }; 63 64 /* 65 * Result of parse. 66 */ 67 struct fs_parse_result { 68 bool negated; /* T if param was "noxxx" */ 69 union { 70 bool boolean; /* For spec_bool */ 71 int int_32; /* For spec_s32/spec_enum */ 72 unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */ 73 u64 uint_64; /* For spec_u64 */ 74 }; 75 }; 76 77 extern int __fs_parse(struct p_log *log, 78 const struct fs_parameter_description *desc, 79 struct fs_parameter *value, 80 struct fs_parse_result *result); 81 82 static inline int fs_parse(struct fs_context *fc, 83 const struct fs_parameter_description *desc, 84 struct fs_parameter *param, 85 struct fs_parse_result *result) 86 { 87 return __fs_parse(&fc->log, desc, param, result); 88 } 89 90 extern int fs_lookup_param(struct fs_context *fc, 91 struct fs_parameter *param, 92 bool want_bdev, 93 struct path *_path); 94 95 extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found); 96 97 #ifdef CONFIG_VALIDATE_FS_PARSER 98 extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 99 int low, int high, int special); 100 extern bool fs_validate_description(const struct fs_parameter_description *desc); 101 #else 102 static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 103 int low, int high, int special) 104 { return true; } 105 static inline bool fs_validate_description(const struct fs_parameter_description *desc) 106 { return true; } 107 #endif 108 109 /* 110 * Parameter type, name, index and flags element constructors. Use as: 111 * 112 * fsparam_xxxx("foo", Opt_foo) 113 * 114 * If existing helpers are not enough, direct use of __fsparam() would 115 * work, but any such case is probably a sign that new helper is needed. 116 * Helpers will remain stable; low-level implementation may change. 117 */ 118 #define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \ 119 { \ 120 .name = NAME, \ 121 .opt = OPT, \ 122 .type = TYPE, \ 123 .flags = FLAGS, \ 124 .data = DATA \ 125 } 126 127 #define fsparam_flag(NAME, OPT) __fsparam(fs_param_is_flag, NAME, OPT, 0, NULL) 128 #define fsparam_flag_no(NAME, OPT) \ 129 __fsparam(fs_param_is_flag, NAME, OPT, \ 130 fs_param_neg_with_no, NULL) 131 #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL) 132 #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL) 133 #define fsparam_u32oct(NAME, OPT) \ 134 __fsparam(fs_param_is_u32_octal, NAME, OPT, 0, NULL) 135 #define fsparam_u32hex(NAME, OPT) \ 136 __fsparam(fs_param_is_u32_hex, NAME, OPT, 0, NULL) 137 #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL) 138 #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL) 139 #define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array) 140 #define fsparam_string(NAME, OPT) \ 141 __fsparam(fs_param_is_string, NAME, OPT, 0, NULL) 142 #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL) 143 #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL) 144 #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL) 145 #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL) 146 147 148 #endif /* _LINUX_FS_PARSER_H */ 149