linux-stable/include/linux/unicode.h
André Almeida 142fa60f61
unicode: Recreate utf8_parse_version()
All filesystems that currently support UTF-8 casefold can fetch the
UTF-8 version from the filesystem metadata stored on disk. They can get
the data stored and directly match it to a integer, so they can skip the
string parsing step, which motivated the removal of this function in the
first place.

However, for tmpfs, the only way to tell the kernel which UTF-8 version
we are about to use is via mount options, using a string. Re-introduce
utf8_parse_version() to be used by tmpfs.

This version differs from the original by skipping the intermediate step
of copying the version string to an auxiliary string before calling
match_token(). This versions calls match_token() in the argument string.
The paramenters are simpler now as well.

utf8_parse_version() was created by 9d53690f0d ("unicode: implement
higher level API for string handling") and later removed by 49bd03cc7e
("unicode: pass a UNICODE_AGE() tripple to utf8_load").

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-4-f443d5814194@igalia.com
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28 13:36:54 +01:00

84 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_UNICODE_H
#define _LINUX_UNICODE_H
#include <linux/init.h>
#include <linux/dcache.h>
struct utf8data;
struct utf8data_table;
#define UNICODE_MAJ_SHIFT 16
#define UNICODE_MIN_SHIFT 8
#define UNICODE_AGE(MAJ, MIN, REV) \
(((unsigned int)(MAJ) << UNICODE_MAJ_SHIFT) | \
((unsigned int)(MIN) << UNICODE_MIN_SHIFT) | \
((unsigned int)(REV)))
#define UTF8_LATEST UNICODE_AGE(12, 1, 0)
static inline u8 unicode_major(unsigned int age)
{
return (age >> UNICODE_MAJ_SHIFT) & 0xff;
}
static inline u8 unicode_minor(unsigned int age)
{
return (age >> UNICODE_MIN_SHIFT) & 0xff;
}
static inline u8 unicode_rev(unsigned int age)
{
return age & 0xff;
}
/*
* Two normalization forms are supported:
* 1) NFDI
* - Apply unicode normalization form NFD.
* - Remove any Default_Ignorable_Code_Point.
* 2) NFDICF
* - Apply unicode normalization form NFD.
* - Remove any Default_Ignorable_Code_Point.
* - Apply a full casefold (C + F).
*/
enum utf8_normalization {
UTF8_NFDI = 0,
UTF8_NFDICF,
UTF8_NMAX,
};
struct unicode_map {
unsigned int version;
const struct utf8data *ntab[UTF8_NMAX];
const struct utf8data_table *tables;
};
int utf8_validate(const struct unicode_map *um, const struct qstr *str);
int utf8_strncmp(const struct unicode_map *um,
const struct qstr *s1, const struct qstr *s2);
int utf8_strncasecmp(const struct unicode_map *um,
const struct qstr *s1, const struct qstr *s2);
int utf8_strncasecmp_folded(const struct unicode_map *um,
const struct qstr *cf,
const struct qstr *s1);
int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen);
int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen);
int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
struct qstr *str);
struct unicode_map *utf8_load(unsigned int version);
void utf8_unload(struct unicode_map *um);
int utf8_parse_version(char *version);
#endif /* _LINUX_UNICODE_H */