unicode: implement higher level API for string handling

This patch integrates the utf8n patches with some higher level API to
perform UTF-8 string comparison, normalization and casefolding
operations.  Implemented is a variation of NFD, and casefold is
performed by doing full casefold on top of NFD.  These algorithms are
based on the core implemented by Olaf Weber from SGI.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Gabriel Krisman Bertazi 2019-04-25 13:51:22 -04:00 committed by Theodore Ts'o
parent a8384c6879
commit 9d53690f0d
5 changed files with 227 additions and 1 deletions

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@ -1,6 +1,8 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_UNICODE) += utf8-norm.o
obj-$(CONFIG_UNICODE) += unicode.o
unicode-y := utf8-norm.o utf8-core.o
# This rule is not invoked during the kernel compilation. It is used to
# regenerate the utf8data.h header file.

187
fs/unicode/utf8-core.c Normal file
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@ -0,0 +1,187 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/parser.h>
#include <linux/errno.h>
#include <linux/unicode.h>
#include "utf8n.h"
int utf8_validate(const struct unicode_map *um, const struct qstr *str)
{
const struct utf8data *data = utf8nfdi(um->version);
if (utf8nlen(data, str->name, str->len) < 0)
return -1;
return 0;
}
EXPORT_SYMBOL(utf8_validate);
int utf8_strncmp(const struct unicode_map *um,
const struct qstr *s1, const struct qstr *s2)
{
const struct utf8data *data = utf8nfdi(um->version);
struct utf8cursor cur1, cur2;
int c1, c2;
if (utf8ncursor(&cur1, data, s1->name, s1->len) < 0)
return -EINVAL;
if (utf8ncursor(&cur2, data, s2->name, s2->len) < 0)
return -EINVAL;
do {
c1 = utf8byte(&cur1);
c2 = utf8byte(&cur2);
if (c1 < 0 || c2 < 0)
return -EINVAL;
if (c1 != c2)
return 1;
} while (c1);
return 0;
}
EXPORT_SYMBOL(utf8_strncmp);
int utf8_strncasecmp(const struct unicode_map *um,
const struct qstr *s1, const struct qstr *s2)
{
const struct utf8data *data = utf8nfdicf(um->version);
struct utf8cursor cur1, cur2;
int c1, c2;
if (utf8ncursor(&cur1, data, s1->name, s1->len) < 0)
return -EINVAL;
if (utf8ncursor(&cur2, data, s2->name, s2->len) < 0)
return -EINVAL;
do {
c1 = utf8byte(&cur1);
c2 = utf8byte(&cur2);
if (c1 < 0 || c2 < 0)
return -EINVAL;
if (c1 != c2)
return 1;
} while (c1);
return 0;
}
EXPORT_SYMBOL(utf8_strncasecmp);
int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen)
{
const struct utf8data *data = utf8nfdicf(um->version);
struct utf8cursor cur;
size_t nlen = 0;
if (utf8ncursor(&cur, data, str->name, str->len) < 0)
return -EINVAL;
for (nlen = 0; nlen < dlen; nlen++) {
int c = utf8byte(&cur);
dest[nlen] = c;
if (!c)
return nlen;
if (c == -1)
break;
}
return -EINVAL;
}
EXPORT_SYMBOL(utf8_casefold);
int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen)
{
const struct utf8data *data = utf8nfdi(um->version);
struct utf8cursor cur;
ssize_t nlen = 0;
if (utf8ncursor(&cur, data, str->name, str->len) < 0)
return -EINVAL;
for (nlen = 0; nlen < dlen; nlen++) {
int c = utf8byte(&cur);
dest[nlen] = c;
if (!c)
return nlen;
if (c == -1)
break;
}
return -EINVAL;
}
EXPORT_SYMBOL(utf8_normalize);
static int utf8_parse_version(const char *version, unsigned int *maj,
unsigned int *min, unsigned int *rev)
{
substring_t args[3];
char version_string[12];
const struct match_token token[] = {
{1, "%d.%d.%d"},
{0, NULL}
};
strncpy(version_string, version, sizeof(version_string));
if (match_token(version_string, token, args) != 1)
return -EINVAL;
if (match_int(&args[0], maj) || match_int(&args[1], min) ||
match_int(&args[2], rev))
return -EINVAL;
return 0;
}
struct unicode_map *utf8_load(const char *version)
{
struct unicode_map *um = NULL;
int unicode_version;
if (version) {
unsigned int maj, min, rev;
if (utf8_parse_version(version, &maj, &min, &rev) < 0)
return ERR_PTR(-EINVAL);
if (!utf8version_is_supported(maj, min, rev))
return ERR_PTR(-EINVAL);
unicode_version = UNICODE_AGE(maj, min, rev);
} else {
unicode_version = utf8version_latest();
printk(KERN_WARNING"UTF-8 version not specified. "
"Assuming latest supported version (%d.%d.%d).",
(unicode_version >> 16) & 0xff,
(unicode_version >> 8) & 0xff,
(unicode_version & 0xff));
}
um = kzalloc(sizeof(struct unicode_map), GFP_KERNEL);
if (!um)
return ERR_PTR(-ENOMEM);
um->charset = "UTF-8";
um->version = unicode_version;
return um;
}
EXPORT_SYMBOL(utf8_load);
void utf8_unload(struct unicode_map *um)
{
kfree(um);
}
EXPORT_SYMBOL(utf8_unload);
MODULE_LICENSE("GPL v2");

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@ -38,6 +38,12 @@ int utf8version_is_supported(u8 maj, u8 min, u8 rev)
}
EXPORT_SYMBOL(utf8version_is_supported);
int utf8version_latest(void)
{
return utf8vers;
}
EXPORT_SYMBOL(utf8version_latest);
/*
* UTF-8 valid ranges.
*

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@ -32,6 +32,7 @@
/* Highest unicode version supported by the data tables. */
extern int utf8version_is_supported(u8 maj, u8 min, u8 rev);
extern int utf8version_latest(void);
/*
* Look for the correct const struct utf8data for a unicode version.

30
include/linux/unicode.h Normal file
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@ -0,0 +1,30 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_UNICODE_H
#define _LINUX_UNICODE_H
#include <linux/init.h>
#include <linux/dcache.h>
struct unicode_map {
const char *charset;
int version;
};
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_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);
struct unicode_map *utf8_load(const char *version);
void utf8_unload(struct unicode_map *um);
#endif /* _LINUX_UNICODE_H */