152 lines
4.8 KiB
C
152 lines
4.8 KiB
C
/* Filesystem parameter description and parser
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*
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* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef _LINUX_FS_PARSER_H
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#define _LINUX_FS_PARSER_H
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#include <linux/fs_context.h>
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struct path;
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struct constant_table {
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const char *name;
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int value;
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};
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/*
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* The type of parameter expected.
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*/
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enum fs_parameter_type {
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__fs_param_wasnt_defined,
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fs_param_is_flag,
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fs_param_is_bool,
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fs_param_is_u32,
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fs_param_is_u32_octal,
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fs_param_is_u32_hex,
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fs_param_is_s32,
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fs_param_is_u64,
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fs_param_is_enum,
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fs_param_is_string,
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fs_param_is_blob,
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fs_param_is_blockdev,
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fs_param_is_path,
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fs_param_is_fd,
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nr__fs_parameter_type,
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};
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/*
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* Specification of the type of value a parameter wants.
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*
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* Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
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* should be used to generate elements of this type.
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*/
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struct fs_parameter_spec {
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const char *name;
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u8 opt; /* Option number (returned by fs_parse()) */
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enum fs_parameter_type type:8; /* The desired parameter type */
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unsigned short flags;
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#define fs_param_v_optional 0x0001 /* The value is optional */
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#define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */
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#define fs_param_neg_with_empty 0x0004 /* "xxx=" is negative param */
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#define fs_param_deprecated 0x0008 /* The param is deprecated */
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};
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struct fs_parameter_enum {
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u8 opt; /* Option number (as fs_parameter_spec::opt) */
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char name[14];
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u8 value;
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};
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struct fs_parameter_description {
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const char name[16]; /* Name for logging purposes */
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const struct fs_parameter_spec *specs; /* List of param specifications */
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const struct fs_parameter_enum *enums; /* Enum values */
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};
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/*
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* Result of parse.
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*/
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struct fs_parse_result {
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bool negated; /* T if param was "noxxx" */
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bool has_value; /* T if value supplied to param */
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union {
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bool boolean; /* For spec_bool */
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int int_32; /* For spec_s32/spec_enum */
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unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */
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u64 uint_64; /* For spec_u64 */
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};
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};
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extern int fs_parse(struct fs_context *fc,
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const struct fs_parameter_description *desc,
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struct fs_parameter *value,
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struct fs_parse_result *result);
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extern int fs_lookup_param(struct fs_context *fc,
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struct fs_parameter *param,
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bool want_bdev,
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struct path *_path);
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extern int __lookup_constant(const struct constant_table tbl[], size_t tbl_size,
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const char *name, int not_found);
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#define lookup_constant(t, n, nf) __lookup_constant(t, ARRAY_SIZE(t), (n), (nf))
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#ifdef CONFIG_VALIDATE_FS_PARSER
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extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
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int low, int high, int special);
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extern bool fs_validate_description(const struct fs_parameter_description *desc);
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#else
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static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
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int low, int high, int special)
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{ return true; }
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static inline bool fs_validate_description(const struct fs_parameter_description *desc)
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{ return true; }
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#endif
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/*
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* Parameter type, name, index and flags element constructors. Use as:
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*
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* fsparam_xxxx("foo", Opt_foo)
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*
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* If existing helpers are not enough, direct use of __fsparam() would
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* work, but any such case is probably a sign that new helper is needed.
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* Helpers will remain stable; low-level implementation may change.
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*/
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#define __fsparam(TYPE, NAME, OPT, FLAGS) \
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{ \
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.name = NAME, \
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.opt = OPT, \
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.type = TYPE, \
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.flags = FLAGS \
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}
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#define fsparam_flag(NAME, OPT) __fsparam(fs_param_is_flag, NAME, OPT, 0)
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#define fsparam_flag_no(NAME, OPT) \
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__fsparam(fs_param_is_flag, NAME, OPT, \
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fs_param_neg_with_no)
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#define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0)
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#define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0)
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#define fsparam_u32oct(NAME, OPT) \
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__fsparam(fs_param_is_u32_octal, NAME, OPT, 0)
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#define fsparam_u32hex(NAME, OPT) \
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__fsparam(fs_param_is_u32_hex, NAME, OPT, 0)
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#define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0)
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#define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0)
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#define fsparam_enum(NAME, OPT) __fsparam(fs_param_is_enum, NAME, OPT, 0)
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#define fsparam_string(NAME, OPT) \
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__fsparam(fs_param_is_string, NAME, OPT, 0)
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#define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0)
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#define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0)
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#define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0)
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#define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0)
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#endif /* _LINUX_FS_PARSER_H */
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