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>
diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
new file mode 100644
index 0000000..6afab4f
--- /dev/null
+++ b/fs/unicode/utf8-core.c
@@ -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");