charset-alias-plugin

configure.ac

@@ -3094,6 +3094,7 @@ src/plugins/imap-zlib/Makefile
 src/plugins/mail-crypt/Makefile
 src/plugins/var-expand-crypt/Makefile
 src/plugins/apparmor/Makefile
+src/plugins/charset-alias/Makefile
 stamp.h
 dovecot-config.in])
 

src/plugins/Makefile.am

@@ -52,4 +52,5 @@ SUBDIRS = \
 	$(DICT_LDAP) \
 	$(APPARMOR) \
 	fs-compress \
-	var-expand-crypt
+	var-expand-crypt \
+	charset-alias	

src/plugins/charset-alias/Makefile.am

@@ -0,0 +1,19 @@
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/src/lib \
+	-I$(top_srcdir)/src/lib-master \
+	-I$(top_srcdir)/src/lib-mail \
+	-I$(top_srcdir)/src/lib-charset \
+	-I$(top_srcdir)/src/lib-index \
+	-I$(top_srcdir)/src/lib-storage 
+
+NOPLUGIN_LDFLAGS =
+lib20_charset_alias_plugin_la_LDFLAGS = -module -avoid-version
+
+module_LTLIBRARIES = \
+	lib20_charset_alias_plugin.la
+
+lib20_charset_alias_plugin_la_SOURCES = \
+	charset-alias-plugin.c
+
+noinst_HEADERS = \
+	charset-alias-plugin.h

src/plugins/charset-alias/charset-alias-plugin.c

@@ -0,0 +1,199 @@
+/* Copyright (c) 2005-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "array.h"
+#include "str.h"
+#include "mail-user.h"
+#include "mail-storage-private.h"
+#include "mail-storage-hooks.h"
+#include "charset-utf8-private.h"
+#include "charset-alias-plugin.h"
+
+
+#define CHARSET_ALIAS_USER_CONTEXT(obj) \
+	MODULE_CONTEXT(obj, charset_alias_user_module)
+
+static MODULE_CONTEXT_DEFINE_INIT(charset_alias_user_module,
+				  &mail_user_module_register);
+
+const char *charset_alias_plugin_version = DOVECOT_ABI_VERSION;
+
+static int charset_alias_to_utf8_begin(const char *charset,
+				       normalizer_func_t *normalizer,
+				       struct charset_translation **t_r);
+
+static void charset_alias_to_utf8_end(struct charset_translation *t);
+
+static void charset_alias_to_utf8_reset(struct charset_translation *t);
+
+static enum charset_result charset_alias_to_utf8(struct charset_translation *t,
+						 const unsigned char *src,
+						 size_t *src_size, buffer_t *dest);
+
+/* charset_utf8_vfuncs is defined in lib-charset/charset-utf8.c */
+extern const struct charset_utf8_vfuncs *charset_utf8_vfuncs;
+
+static const struct charset_utf8_vfuncs *original_charset_utf8_vfuncs;
+
+static const struct charset_utf8_vfuncs charset_alias_utf8_vfuncs = {
+	charset_alias_to_utf8_begin,
+	charset_alias_to_utf8_end,
+	charset_alias_to_utf8_reset,
+	charset_alias_to_utf8
+};
+
+struct charset_alias {
+	const char *charset;
+	const char *alias;
+};
+
+static ARRAY(struct charset_alias) charset_aliases;
+static pool_t charset_alias_pool;
+static int charset_alias_user_refcount = 0;
+
+struct charset_alias_user {
+	union mail_user_module_context module_ctx;
+};
+
+
+static const char *charset_alias_get_alias(const char *charset)
+{
+	const struct charset_alias* elem;
+	const char *key;
+
+	if (array_is_created(&charset_aliases)) {
+		key = t_str_lcase(charset);
+		array_foreach(&charset_aliases, elem) {
+			if (strcmp(key, elem->charset) == 0) {
+				return elem->alias;
+			}
+		}
+	}
+	return charset;
+}
+
+static int charset_alias_to_utf8_begin(const char *charset,
+				       normalizer_func_t *normalizer,
+				       struct charset_translation **t_r)
+{
+	i_assert(original_charset_utf8_vfuncs != NULL);
+	charset = charset_alias_get_alias(charset);
+	return original_charset_utf8_vfuncs->to_utf8_begin(charset, normalizer, t_r);
+}
+static void charset_alias_to_utf8_end(struct charset_translation *t)
+{
+	i_assert(original_charset_utf8_vfuncs != NULL);
+	return original_charset_utf8_vfuncs->to_utf8_end(t);
+}
+
+static void charset_alias_to_utf8_reset(struct charset_translation *t)
+{
+	i_assert(original_charset_utf8_vfuncs != NULL);
+	return original_charset_utf8_vfuncs->to_utf8_reset(t);
+}
+
+static enum charset_result charset_alias_to_utf8(struct charset_translation *t,
+						 const unsigned char *src,
+						 size_t *src_size, buffer_t *dest)
+{
+	i_assert(original_charset_utf8_vfuncs != NULL);
+	return original_charset_utf8_vfuncs->to_utf8(t, src, src_size, dest);
+}
+
+static unsigned int charset_aliases_init(struct mail_user *user, pool_t pool, const char *str)
+{
+	const char *key, *value, *const *keyvalues;
+	struct charset_alias alias;
+	int i;
+
+	i_assert(!array_is_created(&charset_aliases));
+
+	p_array_init(&charset_aliases, pool, 1);
+	keyvalues = t_strsplit_spaces(str, " ");
+	for (i = 0; keyvalues[i] != '\0'; i++) {
+		value = strchr(keyvalues[i], '=');
+		if (value == NULL) {
+			i_error("charset_alias: Missing '=' in charset_aliases setting");
+			continue;
+		}
+		key = t_strdup_until(keyvalues[i], value++);
+		if (key[0] == '\0' || value[0] == '\0') {
+			i_error("charset_alias: charset or alias missing in charset_aliases setting");
+			continue;
+		}
+		if (strcasecmp(key, value) != 0) {
+			if (user->mail_debug)
+				i_debug("charset_alias: add charset-alias %s for %s", value, key);
+			alias.charset = p_strdup(pool, t_str_lcase(key));
+			alias.alias = p_strdup(pool, value);
+			array_append(&charset_aliases, &alias, 1);
+		}
+	}
+	return array_count(&charset_aliases);
+}
+
+static void charset_alias_utf8_vfuncs_set(void)
+{
+	original_charset_utf8_vfuncs = charset_utf8_vfuncs;
+	charset_utf8_vfuncs = &charset_alias_utf8_vfuncs;
+}
+
+static void charset_alias_utf8_vfuncs_reset(void)
+{
+	if (original_charset_utf8_vfuncs != NULL) {
+		charset_utf8_vfuncs = original_charset_utf8_vfuncs;
+		original_charset_utf8_vfuncs = NULL;
+	}
+}
+
+static void charset_alias_mail_user_deinit(struct mail_user *user)
+{
+	struct charset_alias_user *cuser = CHARSET_ALIAS_USER_CONTEXT(user);
+
+	i_assert(charset_alias_user_refcount > 0);
+	if (--charset_alias_user_refcount == 0) {
+		charset_alias_utf8_vfuncs_reset();
+		array_free(&charset_aliases);
+		pool_unref(&charset_alias_pool);
+	}
+
+	cuser->module_ctx.super.deinit(user);
+}
+
+static void charset_alias_mail_user_created(struct mail_user *user)
+{
+	struct mail_user_vfuncs *v = user->vlast;
+	struct charset_alias_user *cuser;
+	const char *str;
+
+	cuser = p_new(user->pool, struct charset_alias_user, 1);
+	cuser->module_ctx.super = *v;
+	user->vlast = &cuser->module_ctx.super;
+	v->deinit = charset_alias_mail_user_deinit;
+
+	if (charset_alias_user_refcount++ == 0) {
+		charset_alias_pool = pool_alloconly_create("charset_alias alias list", 128);
+		str = mail_user_plugin_getenv(user, "charset_aliases");
+		if (str != NULL && str[0] != '\0') {
+			if (charset_aliases_init(user, charset_alias_pool, str) > 0) {
+				charset_alias_utf8_vfuncs_set();
+			}
+		}
+	}
+
+	MODULE_CONTEXT_SET(user, charset_alias_user_module, cuser);
+}
+
+static struct mail_storage_hooks charset_alias_mail_storage_hooks = {
+	.mail_user_created = charset_alias_mail_user_created
+};
+
+void charset_alias_plugin_init(struct module *module)
+{
+	mail_storage_hooks_add(module, &charset_alias_mail_storage_hooks);
+}
+
+void charset_alias_plugin_deinit(void)
+{
+	mail_storage_hooks_remove(&charset_alias_mail_storage_hooks);
+}

src/plugins/charset-alias/charset-alias-plugin.h

@@ -0,0 +1,7 @@
+#ifndef CHARSET_ALIAS_PLUGIN_H
+#define CHARSET_ALIAS_PLUGIN_H
+
+void charset_alias_plugin_init(struct module *module);
+void charset_alias_plugin_deinit(void);
+
+#endif