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-rw-r--r--include/linux/fs_parser.h151
1 files changed, 151 insertions, 0 deletions
diff --git a/include/linux/fs_parser.h b/include/linux/fs_parser.h
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+++ 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 */