1 files changed, 151 insertions, 0 deletions
diff --git a/include/linux/fs_parser.h b/include/linux/fs_parser.h
new file mode 100644
index 000000000000..d966f96ffe62
--- /dev/null
+++ b/include/linux/fs_parser.h
@@ -0,0 +1,151 @@
+/* Filesystem parameter description and parser
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_FS_PARSER_H
+#define _LINUX_FS_PARSER_H
+
+#include <linux/fs_context.h>
+
+struct path;
+
+struct constant_table {
+	const char	*name;
+	int		value;
+};
+
+/*
+ * The type of parameter expected.
+ */
+enum fs_parameter_type {
+	__fs_param_wasnt_defined,
+	fs_param_is_flag,
+	fs_param_is_bool,
+	fs_param_is_u32,
+	fs_param_is_u32_octal,
+	fs_param_is_u32_hex,
+	fs_param_is_s32,
+	fs_param_is_u64,
+	fs_param_is_enum,
+	fs_param_is_string,
+	fs_param_is_blob,
+	fs_param_is_blockdev,
+	fs_param_is_path,
+	fs_param_is_fd,
+	nr__fs_parameter_type,
+};
+
+/*
+ * Specification of the type of value a parameter wants.
+ *
+ * Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
+ * should be used to generate elements of this type.
+ */
+struct fs_parameter_spec {
+	const char		*name;
+	u8			opt;	/* Option number (returned by fs_parse()) */
+	enum fs_parameter_type	type:8;	/* The desired parameter type */
+	unsigned short		flags;
+#define fs_param_v_optional	0x0001	/* The value is optional */
+#define fs_param_neg_with_no	0x0002	/* "noxxx" is negative param */
+#define fs_param_neg_with_empty	0x0004	/* "xxx=" is negative param */
+#define fs_param_deprecated	0x0008	/* The param is deprecated */
+};
+
+struct fs_parameter_enum {
+	u8		opt;		/* Option number (as fs_parameter_spec::opt) */
+	char		name[14];
+	u8		value;
+};
+
+struct fs_parameter_description {
+	const char	name[16];		/* Name for logging purposes */
+	const struct fs_parameter_spec *specs;	/* List of param specifications */
+	const struct fs_parameter_enum *enums;	/* Enum values */
+};
+
+/*
+ * Result of parse.
+ */
+struct fs_parse_result {
+	bool			negated;	/* T if param was "noxxx" */
+	bool			has_value;	/* T if value supplied to param */
+	union {
+		bool		boolean;	/* For spec_bool */
+		int		int_32;		/* For spec_s32/spec_enum */
+		unsigned int	uint_32;	/* For spec_u32{,_octal,_hex}/spec_enum */
+		u64		uint_64;	/* For spec_u64 */
+	};
+};
+
+extern int fs_parse(struct fs_context *fc,
+		    const struct fs_parameter_description *desc,
+		    struct fs_parameter *value,
+		    struct fs_parse_result *result);
+extern int fs_lookup_param(struct fs_context *fc,
+			   struct fs_parameter *param,
+			   bool want_bdev,
+			   struct path *_path);
+
+extern int __lookup_constant(const struct constant_table tbl[], size_t tbl_size,
+			     const char *name, int not_found);
+#define lookup_constant(t, n, nf) __lookup_constant(t, ARRAY_SIZE(t), (n), (nf))
+
+#ifdef CONFIG_VALIDATE_FS_PARSER
+extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
+				    int low, int high, int special);
+extern bool fs_validate_description(const struct fs_parameter_description *desc);
+#else
+static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
+					   int low, int high, int special)
+{ return true; }
+static inline bool fs_validate_description(const struct fs_parameter_description *desc)
+{ return true; }
+#endif
+
+/*
+ * Parameter type, name, index and flags element constructors.  Use as:
+ *
+ *  fsparam_xxxx("foo", Opt_foo)
+ *
+ * If existing helpers are not enough, direct use of __fsparam() would
+ * work, but any such case is probably a sign that new helper is needed.
+ * Helpers will remain stable; low-level implementation may change.
+ */
+#define __fsparam(TYPE, NAME, OPT, FLAGS) \
+	{ \
+		.name = NAME, \
+		.opt = OPT, \
+		.type = TYPE, \
+		.flags = FLAGS \
+	}
+
+#define fsparam_flag(NAME, OPT)	__fsparam(fs_param_is_flag, NAME, OPT, 0)
+#define fsparam_flag_no(NAME, OPT) \
+				__fsparam(fs_param_is_flag, NAME, OPT, \
+					    fs_param_neg_with_no)
+#define fsparam_bool(NAME, OPT)	__fsparam(fs_param_is_bool, NAME, OPT, 0)
+#define fsparam_u32(NAME, OPT)	__fsparam(fs_param_is_u32, NAME, OPT, 0)
+#define fsparam_u32oct(NAME, OPT) \
+				__fsparam(fs_param_is_u32_octal, NAME, OPT, 0)
+#define fsparam_u32hex(NAME, OPT) \
+				__fsparam(fs_param_is_u32_hex, NAME, OPT, 0)
+#define fsparam_s32(NAME, OPT)	__fsparam(fs_param_is_s32, NAME, OPT, 0)
+#define fsparam_u64(NAME, OPT)	__fsparam(fs_param_is_u64, NAME, OPT, 0)
+#define fsparam_enum(NAME, OPT)	__fsparam(fs_param_is_enum, NAME, OPT, 0)
+#define fsparam_string(NAME, OPT) \
+				__fsparam(fs_param_is_string, NAME, OPT, 0)
+#define fsparam_blob(NAME, OPT)	__fsparam(fs_param_is_blob, NAME, OPT, 0)
+#define fsparam_bdev(NAME, OPT)	__fsparam(fs_param_is_blockdev, NAME, OPT, 0)
+#define fsparam_path(NAME, OPT)	__fsparam(fs_param_is_path, NAME, OPT, 0)
+#define fsparam_fd(NAME, OPT)	__fsparam(fs_param_is_fd, NAME, OPT, 0)
+
+
+#endif /* _LINUX_FS_PARSER_H */