linux/fs/unicode/utf8-core.c
Daniel Rosenberg 3d7bfea8b8 unicode: Add utf8_casefold_hash
This adds a case insensitive hash function to allow taking the hash
without needing to allocate a casefolded copy of the string.

The existing d_hash implementations for casefolding allocate memory
within rcu-walk, by avoiding it we can be more efficient and avoid
worrying about a failed allocation.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2020-09-10 14:03:31 -07:00

237 lines
4.9 KiB
C

/* 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 <linux/stringhash.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);
/* String cf is expected to be a valid UTF-8 casefolded
* string.
*/
int utf8_strncasecmp_folded(const struct unicode_map *um,
const struct qstr *cf,
const struct qstr *s1)
{
const struct utf8data *data = utf8nfdicf(um->version);
struct utf8cursor cur1;
int c1, c2;
int i = 0;
if (utf8ncursor(&cur1, data, s1->name, s1->len) < 0)
return -EINVAL;
do {
c1 = utf8byte(&cur1);
c2 = cf->name[i++];
if (c1 < 0)
return -EINVAL;
if (c1 != c2)
return 1;
} while (c1);
return 0;
}
EXPORT_SYMBOL(utf8_strncasecmp_folded);
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_casefold_hash(const struct unicode_map *um, const void *salt,
struct qstr *str)
{
const struct utf8data *data = utf8nfdicf(um->version);
struct utf8cursor cur;
int c;
unsigned long hash = init_name_hash(salt);
if (utf8ncursor(&cur, data, str->name, str->len) < 0)
return -EINVAL;
while ((c = utf8byte(&cur))) {
if (c < 0)
return -EINVAL;
hash = partial_name_hash((unsigned char)c, hash);
}
str->hash = end_name_hash(hash);
return 0;
}
EXPORT_SYMBOL(utf8_casefold_hash);
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];
static 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");