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 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 kuid_t uid; 61 kgid_t gid; 62 }; 63 }; 64 65 extern int __fs_parse(struct p_log *log, 66 const struct fs_parameter_spec *desc, 67 struct fs_parameter *value, 68 struct fs_parse_result *result); 69 fs_parse(struct fs_context * fc,const struct fs_parameter_spec * desc,struct fs_parameter * param,struct fs_parse_result * result)70 static inline int fs_parse(struct fs_context *fc, 71 const struct fs_parameter_spec *desc, 72 struct fs_parameter *param, 73 struct fs_parse_result *result) 74 { 75 return __fs_parse(&fc->log, desc, param, result); 76 } 77 78 extern int fs_lookup_param(struct fs_context *fc, 79 struct fs_parameter *param, 80 bool want_bdev, 81 unsigned int flags, 82 struct path *_path); 83 84 extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found); 85 86 #ifdef CONFIG_VALIDATE_FS_PARSER 87 extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 88 int low, int high, int special); 89 extern bool fs_validate_description(const char *name, 90 const struct fs_parameter_spec *desc); 91 #else validate_constant_table(const struct constant_table * tbl,size_t tbl_size,int low,int high,int special)92 static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, 93 int low, int high, int special) 94 { return true; } fs_validate_description(const char * name,const struct fs_parameter_spec * desc)95 static inline bool fs_validate_description(const char *name, 96 const struct fs_parameter_spec *desc) 97 { return true; } 98 #endif 99 100 /* 101 * Parameter type, name, index and flags element constructors. Use as: 102 * 103 * fsparam_xxxx("foo", Opt_foo) 104 * 105 * If existing helpers are not enough, direct use of __fsparam() would 106 * work, but any such case is probably a sign that new helper is needed. 107 * Helpers will remain stable; low-level implementation may change. 108 */ 109 #define __fsparam(TYPE, NAME, OPT, FLAGS, DATA) \ 110 { \ 111 .name = NAME, \ 112 .opt = OPT, \ 113 .type = TYPE, \ 114 .flags = FLAGS, \ 115 .data = DATA \ 116 } 117 118 #define fsparam_flag(NAME, OPT) __fsparam(NULL, NAME, OPT, 0, NULL) 119 #define fsparam_flag_no(NAME, OPT) \ 120 __fsparam(NULL, NAME, OPT, fs_param_neg_with_no, NULL) 121 #define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0, NULL) 122 #define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0, NULL) 123 #define fsparam_u32oct(NAME, OPT) \ 124 __fsparam(fs_param_is_u32, NAME, OPT, 0, (void *)8) 125 #define fsparam_u32hex(NAME, OPT) \ 126 __fsparam(fs_param_is_u32_hex, NAME, OPT, 0, (void *)16) 127 #define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0, NULL) 128 #define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0, NULL) 129 #define fsparam_enum(NAME, OPT, array) __fsparam(fs_param_is_enum, NAME, OPT, 0, array) 130 #define fsparam_string(NAME, OPT) \ 131 __fsparam(fs_param_is_string, NAME, OPT, 0, NULL) 132 #define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0, NULL) 133 #define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL) 134 #define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0, NULL) 135 #define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0, NULL) 136 #define fsparam_uid(NAME, OPT) __fsparam(fs_param_is_uid, NAME, OPT, 0, NULL) 137 #define fsparam_gid(NAME, OPT) __fsparam(fs_param_is_gid, NAME, OPT, 0, NULL) 138 139 /* String parameter that allows empty argument */ 140 #define fsparam_string_empty(NAME, OPT) \ 141 __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) 142 143 #endif /* _LINUX_FS_PARSER_H */ 144