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, fs_param_is_uid, fs_param_is_gid, 32 fs_param_is_file_or_string; 33 34 /* 35 * Specification of the type of value a parameter wants. 36 * 37 * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros 38 * should be used to generate elements of this type. 39 */ 40 struct fs_parameter_spec { 41 const char *name; 42 fs_param_type *type; /* The desired parameter type */ 43 u8 opt; /* Option number (returned by fs_parse()) */ 44 unsigned short flags; 45 #define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */ 46 #define fs_param_can_be_empty 0x0004 /* "xxx=" is allowed */ 47 #define fs_param_deprecated 0x0008 /* The param is deprecated */ 48 const void *data; 49 }; 50 51 /* 52 * Result of parse. 53 */ 54 struct fs_parse_result { 55 bool negated; /* T if param was "noxxx" */ 56 union { 57 bool boolean; /* For spec_bool */ 58 int int_32; /* For spec_s32/spec_enum */ 59 unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */ 60 u64 uint_64; /* For spec_u64 */ 61 kuid_t uid; 62 kgid_t gid; 63 }; 64 }; 65 66 extern int __fs_parse(struct p_log *log, 67 const struct fs_parameter_spec *desc, 68 struct fs_parameter *value, 69 struct fs_parse_result *result); 70 fs_parse(struct fs_context * fc,const struct fs_parameter_spec * desc,struct fs_parameter * param,struct fs_parse_result * result)71 static inline int fs_parse(struct fs_context *fc, 72 const struct fs_parameter_spec *desc, 73 struct fs_parameter *param, 74 struct fs_parse_result *result) 75 { 76 return __fs_parse(&fc->log, desc, param, result); 77 } 78 79 extern int fs_lookup_param(struct fs_context *fc, 80 struct fs_parameter *param, 81 bool want_bdev, 82 unsigned int flags, 83 struct path *_path); 84 85 extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found); 86 87 extern const struct constant_table bool_names[]; 88 89 #ifdef CONFIG_VALIDATE_FS_PARSER 90 extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 91 int low, int high, int special); 92 extern bool fs_validate_description(const char *name, 93 const struct fs_parameter_spec *desc); 94 #else validate_constant_table(const struct constant_table * tbl,size_t tbl_size,int low,int high,int special)95 static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 96 int low, int high, int special) 97 { return true; } fs_validate_description(const char * name,const struct fs_parameter_spec * desc)98 static inline bool fs_validate_description(const char *name, 99 const struct fs_parameter_spec *desc) 100 { return true; } 101 #endif 102 103 /* 104 * Parameter type, name, index and flags element constructors. Use as: 105 * 106 * fsparam_xxxx("foo", Opt_foo) 107 * 108 * If existing helpers are not enough, direct use of __fsparam() would 109 * work, but any such case is probably a sign that new helper is needed. 110 * Helpers will remain stable; low-level implementation may change. 111 */ 112 #define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \ 113 { \ 114 .name = NAME, \ 115 .opt = OPT, \ 116 .type = TYPE, \ 117 .flags = FLAGS, \ 118 .data = DATA \ 119 } 120 121 #define fsparam_flag(NAME, OPT) __fsparam(NULL, NAME, OPT, 0, NULL) 122 #define fsparam_flag_no(NAME, OPT) \ 123 __fsparam(NULL, NAME, OPT, fs_param_neg_with_no, NULL) 124 #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL) 125 #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL) 126 #define fsparam_u32oct(NAME, OPT) \ 127 __fsparam(fs_param_is_u32, NAME, OPT, 0, (void *)8) 128 #define fsparam_u32hex(NAME, OPT) \ 129 __fsparam(fs_param_is_u32_hex, NAME, OPT, 0, (void *)16) 130 #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL) 131 #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL) 132 #define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array) 133 #define fsparam_string(NAME, OPT) \ 134 __fsparam(fs_param_is_string, NAME, OPT, 0, NULL) 135 #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL) 136 #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL) 137 #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL) 138 #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL) 139 #define fsparam_file_or_string(NAME, OPT) \ 140 __fsparam(fs_param_is_file_or_string, NAME, OPT, 0, NULL) 141 #define fsparam_uid(NAME, OPT) __fsparam(fs_param_is_uid, NAME, OPT, 0, NULL) 142 #define fsparam_gid(NAME, OPT) __fsparam(fs_param_is_gid, NAME, OPT, 0, NULL) 143 144 /* String parameter that allows empty argument */ 145 #define fsparam_string_empty(NAME, OPT) \ 146 __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) 147 148 #endif /* _LINUX_FS_PARSER_H */ 149