This implements an abstraction for high-level encoding-wise string
manipulation functions. It defines some hooks that encoding modules must
implement, which will be used by filesystem code to support lookups that
consider normalization and case-folding.
Changes since RFC v1:
- Export charset_load symbol.
- Include length parameter for second string on comparison functions.
- Changed length type to size_t.
- Fix bad memory access when trying to load invalid charset
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxxxx>
---
include/linux/charsets.h | 75 ++++++++++++++++++++++++++++++++++++++++++++++++
lib/Kconfig | 2 ++
lib/Makefile | 2 ++
lib/charsets/Makefile | 3 ++
lib/charsets/core.c | 69 ++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 151 insertions(+)
create mode 100644 include/linux/charsets.h
create mode 100644 lib/charsets/Makefile
create mode 100644 lib/charsets/core.c
diff --git a/include/linux/charsets.h b/include/linux/charsets.h
new file mode 100644
index 000000000000..3abe92cc0bc6
--- /dev/null
+++ b/include/linux/charsets.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2017 Collabora Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _CHARSET_H
+#define _CHARSET_H
+
+#include <linux/types.h>
+
+struct charset_info;
+struct charset;
+
+struct charset_ops {
+ int (*strncmp)(const struct charset *charset, const char *str1,
+ size_t len1, const char *str2, size_t len2);
+ int (*strncasecmp)(const struct charset *charset, const char *str1,
+ size_t len1, const char *str2, size_t len2);
+ int (*casefold)(const struct charset *charset, const char *str,
+ int len, char **folded);
+ int (*normalize)(const struct charset *charset, const char *str,
+ int len, char **normalization);
+};
+
+struct charset {
+ const struct charset_info *info;
+ unsigned int version;
+ const struct charset_ops *ops;
+};
+
+struct charset_info {
+ char *name;
+ char *match_token;
+ struct charset* (*load_charset)(void *args);
+};
+
+static inline int charset_strncmp(const struct charset *charset,
+ const char *str1, size_t len1,
+ const char *str2, size_t len2)
+{
+ return charset->ops->strncmp(charset, str1, len1, str2, len2);
+}
+
+static inline int charset_strncasecmp(const struct charset *charset,
+ const char *str1, size_t len1,
+ const char *str2, size_t len2)
+{
+ return charset->ops->strncasecmp(charset, str1, len1, str2, len2);
+}
+
+static inline int charset_casefold(const struct charset *charset,
+ const char *str, int len, char **folded)
+{
+ return charset->ops->casefold(charset, str, len, folded);
+}
+
+static inline int charset_normalize(const struct charset *charset,
+ const char *str, int len,
+ char **normalization)
+{
+ return charset->ops->normalize(charset, str, len, normalization);
+}
+
+int charset_register(struct charset_info *charset);
+const struct charset *charset_load(char *charset);
+#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index c5e84fbcb30b..bf5c751cfb8a 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -582,6 +582,8 @@ config PRIME_NUMBERS
config STRING_SELFTEST
tristate "Test string functions"
+config CHARSETS
+ tristate "Character encoding sets"
endmenu
config GENERIC_ASHLDI3
diff --git a/lib/Makefile b/lib/Makefile
index d11c48ec8ffd..f6b2360fedfa 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -258,3 +258,5 @@ obj-$(CONFIG_GENERIC_LSHRDI3) += lshrdi3.o
obj-$(CONFIG_GENERIC_MULDI3) += muldi3.o
obj-$(CONFIG_GENERIC_CMPDI2) += cmpdi2.o
obj-$(CONFIG_GENERIC_UCMPDI2) += ucmpdi2.o
+
+obj-$(CONFIG_CHARSETS) += charsets/
diff --git a/lib/charsets/Makefile b/lib/charsets/Makefile
new file mode 100644
index 000000000000..01ff9fd09f98
--- /dev/null
+++ b/lib/charsets/Makefile
@@ -0,0 +1,3 @@
+charsets-y += core.o
+
+obj-$(CONFIG_CHARSETS) += charsets.o
diff --git a/lib/charsets/core.c b/lib/charsets/core.c
new file mode 100644
index 000000000000..238088cbb641
--- /dev/null
+++ b/lib/charsets/core.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2017 Collabora Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/charsets.h>
+#include <linux/parser.h>
+
+#define MAX_ENCODINGS 10
+
+static struct match_token encoding_tokens[MAX_ENCODINGS + 1];
+static struct charset_info *charsets[MAX_ENCODINGS];
+static int n_encodings;
+
+const struct charset *charset_load(char *charset)
+{
+ substring_t args[MAX_OPT_ARGS];
+ int token;
+
+ args[0].to = args[0].from = NULL;
+ token = match_token(charset, encoding_tokens, args);
+
+ if (!encoding_tokens[token].pattern)
+ return NULL;
+
+ return charsets[token]->load_charset(args);
+}
+EXPORT_SYMBOL(charset_load);
+
+int charset_register(struct charset_info *charset)
+{
+ encoding_tokens[n_encodings].token = n_encodings;
+ encoding_tokens[n_encodings].pattern = charset->match_token;
+
+ charsets[n_encodings] = charset;
+ n_encodings += 1;
+ return 0;
+}
+EXPORT_SYMBOL(charset_register);
+
+static int __init init_charset(void)
+{
+ memset(encoding_tokens, 0, sizeof(encoding_tokens));
+ n_encodings = 0;
+
+ return 0;
+}
+
+static void __exit exit_charset(void)
+{
+}
+
+module_init(init_charset);
+module_exit(exit_charset);
+
+MODULE_AUTHOR("Gabriel Krisman Bertazi");
+MODULE_DESCRIPTION("charset abstraction for filesystems");
+MODULE_LICENSE("GPL");
--
2.15.1
