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			134 lines
		
	
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			134 lines
		
	
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* 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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#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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struct fs_parameter_spec;
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struct fs_parse_result;
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typedef int fs_param_type(struct p_log *,
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			  const struct fs_parameter_spec *,
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			  struct fs_parameter *,
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			  struct fs_parse_result *);
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/*
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 * The type of parameter expected.
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 */
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fs_param_type fs_param_is_bool, fs_param_is_u32, fs_param_is_s32, fs_param_is_u64,
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	fs_param_is_enum, fs_param_is_string, fs_param_is_blob, fs_param_is_blockdev,
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	fs_param_is_path, fs_param_is_fd;
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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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	fs_param_type		*type;	/* The desired parameter type */
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	u8			opt;	/* Option number (returned by fs_parse()) */
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	unsigned short		flags;
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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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	const void		*data;
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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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	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 p_log *log,
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		    const struct fs_parameter_spec *desc,
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		    struct fs_parameter *value,
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		    struct fs_parse_result *result);
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static inline int fs_parse(struct fs_context *fc,
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	     const struct fs_parameter_spec *desc,
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	     struct fs_parameter *param,
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	     struct fs_parse_result *result)
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{
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	return __fs_parse(&fc->log, desc, param, result);
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}
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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[], const char *name, int not_found);
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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 char *name,
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				    const struct fs_parameter_spec *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 char *name,
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					   const struct fs_parameter_spec *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, DATA) \
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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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		.data = DATA \
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	}
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#define fsparam_flag(NAME, OPT)	__fsparam(NULL, NAME, OPT, 0, NULL)
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#define fsparam_flag_no(NAME, OPT) \
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			__fsparam(NULL, NAME, OPT, fs_param_neg_with_no, NULL)
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#define fsparam_bool(NAME, OPT)	__fsparam(fs_param_is_bool, NAME, OPT, 0, NULL)
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#define fsparam_u32(NAME, OPT)	__fsparam(fs_param_is_u32, NAME, OPT, 0, NULL)
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#define fsparam_u32oct(NAME, OPT) \
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			__fsparam(fs_param_is_u32, NAME, OPT, 0, (void *)8)
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#define fsparam_u32hex(NAME, OPT) \
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			__fsparam(fs_param_is_u32_hex, NAME, OPT, 0, (void *16))
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#define fsparam_s32(NAME, OPT)	__fsparam(fs_param_is_s32, NAME, OPT, 0, NULL)
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#define fsparam_u64(NAME, OPT)	__fsparam(fs_param_is_u64, NAME, OPT, 0, NULL)
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#define fsparam_enum(NAME, OPT, array)	__fsparam(fs_param_is_enum, NAME, OPT, 0, array)
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#define fsparam_string(NAME, OPT) \
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				__fsparam(fs_param_is_string, NAME, OPT, 0, NULL)
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#define fsparam_blob(NAME, OPT)	__fsparam(fs_param_is_blob, NAME, OPT, 0, NULL)
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#define fsparam_bdev(NAME, OPT)	__fsparam(fs_param_is_blockdev, NAME, OPT, 0, NULL)
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#define fsparam_path(NAME, OPT)	__fsparam(fs_param_is_path, NAME, OPT, 0, NULL)
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#define fsparam_fd(NAME, OPT)	__fsparam(fs_param_is_fd, NAME, OPT, 0, NULL)
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#endif /* _LINUX_FS_PARSER_H */
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