From f73f190c3f97479f735b97c22a8e4885344edca1 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Tue, 16 Apr 2019 16:35:35 +0200
Subject: [PATCH] Fix internal_encoding fallback in mbstring

By introducing a hook that is called whenever one of
internal_encoding / input_encoding / output_encoding changes, so
that mbstring can adjust it's internal state.

This also makes internal_encoding work with zend multibyte.
---
 NEWS                                          |   3 +
 Zend/tests/multibyte/bug68665.phpt            |   2 +-
 .../multibyte/multibyte_encoding_001.phpt     |   2 +-
 .../multibyte/multibyte_encoding_002.phpt     |   2 +-
 .../multibyte/multibyte_encoding_003.phpt     | Bin 471 -> 462 bytes
 .../multibyte/multibyte_encoding_004.phpt     |   2 +-
 .../multibyte/multibyte_encoding_005.phpt     |   2 +-
 ext/iconv/iconv.c                             |  36 ++--
 ext/mbstring/mb_gpc.c                         |   5 -
 ext/mbstring/mbstring.c                       | 156 ++++++++----------
 ext/mbstring/mbstring.h                       |   7 +-
 ext/mbstring/tests/ini_encoding2.phpt         |   2 +-
 ext/mbstring/tests/internal_encoding.phpt     |  66 ++++++++
 .../tests/mb_internal_encoding_basic2.phpt    |   2 +-
 main/main.c                                   |  41 +++++
 main/php.h                                    |   5 +
 16 files changed, 211 insertions(+), 122 deletions(-)
 create mode 100644 ext/mbstring/tests/internal_encoding.phpt

diff --git a/NEWS b/NEWS
index 63f7704f05..08340c8536 100644
--- a/NEWS
+++ b/NEWS
@@ -60,6 +60,9 @@ PHP                                                                        NEWS
 - LDAP:
   . Deprecated ldap_control_paged_result_response and ldap_control_paged_result
 
+- Mbstring:
+  . Fixed bug #77907 (mb-functions do not respect default_encoding). (Nikita)
+
 - Opcache:
   . Implemented preloading RFC: https://wiki.php.net/rfc/preload. (Dmitry)
 
diff --git a/Zend/tests/multibyte/bug68665.phpt b/Zend/tests/multibyte/bug68665.phpt
index 74ff01da33..6846776570 100644
--- a/Zend/tests/multibyte/bug68665.phpt
+++ b/Zend/tests/multibyte/bug68665.phpt
@@ -11,7 +11,7 @@ if (!extension_loaded("mbstring")) {
 ?>
 --INI--
 zend.multibyte=1
-mbstring.internal_encoding=big5
+internal_encoding=big5
 --FILE--
 <?php
 echo '\'hello';
diff --git a/Zend/tests/multibyte/multibyte_encoding_001.phpt b/Zend/tests/multibyte/multibyte_encoding_001.phpt
index 38aa80a40a..1a094814ec 100644
--- a/Zend/tests/multibyte/multibyte_encoding_001.phpt
+++ b/Zend/tests/multibyte/multibyte_encoding_001.phpt
@@ -11,7 +11,7 @@ if (!extension_loaded("mbstring")) {
 ?>
 --INI--
 zend.multibyte=1
-mbstring.internal_encoding=SJIS
+internal_encoding=SJIS
 --FILE--
 <?php
 declare(encoding='Shift_JIS');
diff --git a/Zend/tests/multibyte/multibyte_encoding_002.phpt b/Zend/tests/multibyte/multibyte_encoding_002.phpt
index 6e1ad80c9f..58ea015a6f 100644
--- a/Zend/tests/multibyte/multibyte_encoding_002.phpt
+++ b/Zend/tests/multibyte/multibyte_encoding_002.phpt
@@ -11,7 +11,7 @@ if (!extension_loaded("mbstring")) {
 ?>
 --INI--
 zend.multibyte=1
-mbstring.internal_encoding=iso-8859-1
+internal_encoding=iso-8859-1
 --FILE--
 <?php
 print "Hello World\n";
diff --git a/Zend/tests/multibyte/multibyte_encoding_003.phpt b/Zend/tests/multibyte/multibyte_encoding_003.phpt
index 0f873dd07cd13ec3e9f9877d41056d8604d459e7..ee861dbcc482bb117f7f09a8c35d7ddf620bc2c3 100644
GIT binary patch
delta 11
Scmcc4e2#g84&!7~#zg=cC<F8W

delta 21
ccmX@de4TlN4kKr7QgKO9W?s79WF5vu096SGhyVZp

diff --git a/Zend/tests/multibyte/multibyte_encoding_004.phpt b/Zend/tests/multibyte/multibyte_encoding_004.phpt
index 6d121d6680..1b4f4fecef 100644
--- a/Zend/tests/multibyte/multibyte_encoding_004.phpt
+++ b/Zend/tests/multibyte/multibyte_encoding_004.phpt
@@ -12,7 +12,7 @@ if (!extension_loaded("mbstring")) {
 --INI--
 zend.multibyte=1
 zend.script_encoding=Shift_JIS
-mbstring.internal_encoding=Shift_JIS
+internal_encoding=Shift_JIS
 --FILE--
 <?php
 	function —\Ž\”\($ˆø”)
diff --git a/Zend/tests/multibyte/multibyte_encoding_005.phpt b/Zend/tests/multibyte/multibyte_encoding_005.phpt
index 6fee687483..305175d0cc 100644
--- a/Zend/tests/multibyte/multibyte_encoding_005.phpt
+++ b/Zend/tests/multibyte/multibyte_encoding_005.phpt
@@ -13,7 +13,7 @@ if (!extension_loaded("mbstring")) {
 zend.multibyte=1
 mbstring.encoding_translation = On
 zend.script_encoding=Shift_JIS
-mbstring.internal_encoding=UTF-8
+internal_encoding=UTF-8
 --FILE--
 <?php
 	function —\Ž\”\($ˆø”)
diff --git a/ext/iconv/iconv.c b/ext/iconv/iconv.c
index 62f7cb3af1..7e8852cc47 100644
--- a/ext/iconv/iconv.c
+++ b/ext/iconv/iconv.c
@@ -338,37 +338,25 @@ PHP_MINFO_FUNCTION(miconv)
 }
 /* }}} */
 
-static char *get_internal_encoding(void) {
+static const char *get_internal_encoding(void) {
 	if (ICONVG(internal_encoding) && ICONVG(internal_encoding)[0]) {
 		return ICONVG(internal_encoding);
-	} else if (PG(internal_encoding) && PG(internal_encoding)[0]) {
-		return PG(internal_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
 	}
-	return "";
+	return php_get_internal_encoding();
 }
 
-static char *get_input_encoding(void) {
+static const char *get_input_encoding(void) {
 	if (ICONVG(input_encoding) && ICONVG(input_encoding)[0]) {
 		return ICONVG(input_encoding);
-	} else if (PG(input_encoding) && PG(input_encoding)[0]) {
-		return PG(input_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
 	}
-	return "";
+	return php_get_input_encoding();
 }
 
-static char *get_output_encoding(void) {
+static const char *get_output_encoding(void) {
 	if (ICONVG(output_encoding) && ICONVG(output_encoding)[0]) {
 		return ICONVG(output_encoding);
-	} else if (PG(output_encoding) && PG(output_encoding)[0]) {
-		return PG(output_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
 	}
-	return "";
+	return php_get_output_encoding();
 }
 
 
@@ -2064,7 +2052,7 @@ static void _php_iconv_show_error(php_iconv_err_t err, const char *out_charset,
    Returns the character count of str */
 PHP_FUNCTION(iconv_strlen)
 {
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0;
 	zend_string *str;
 
@@ -2096,7 +2084,7 @@ PHP_FUNCTION(iconv_strlen)
    Returns specified part of a string */
 PHP_FUNCTION(iconv_substr)
 {
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0;
 	zend_string *str;
 	zend_long offset, length = 0;
@@ -2135,7 +2123,7 @@ PHP_FUNCTION(iconv_substr)
    Finds position of first occurrence of needle within part of haystack beginning with offset */
 PHP_FUNCTION(iconv_strpos)
 {
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0, haystk_len;
 	zend_string *haystk;
 	zend_string *ndl;
@@ -2190,7 +2178,7 @@ PHP_FUNCTION(iconv_strpos)
    Finds position of last occurrence of needle within part of haystack beginning with offset */
 PHP_FUNCTION(iconv_strrpos)
 {
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0;
 	zend_string *haystk;
 	zend_string *ndl;
@@ -2331,7 +2319,7 @@ PHP_FUNCTION(iconv_mime_encode)
 PHP_FUNCTION(iconv_mime_decode)
 {
 	zend_string *encoded_str;
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0;
 	zend_long mode = 0;
 
@@ -2371,7 +2359,7 @@ PHP_FUNCTION(iconv_mime_decode)
 PHP_FUNCTION(iconv_mime_decode_headers)
 {
 	zend_string *encoded_str;
-	char *charset = get_internal_encoding();
+	const char *charset = get_internal_encoding();
 	size_t charset_len = 0;
 	zend_long mode = 0;
 	char *enc_str_tmp;
diff --git a/ext/mbstring/mb_gpc.c b/ext/mbstring/mb_gpc.c
index 2a6a9b23bb..c57e2b6be1 100644
--- a/ext/mbstring/mb_gpc.c
+++ b/ext/mbstring/mb_gpc.c
@@ -58,11 +58,6 @@ MBSTRING_API SAPI_TREAT_DATA_FUNC(mbstr_treat_data)
 	const mbfl_encoding *detected;
 	php_mb_encoding_handler_info_t info;
 
-	if (arg != PARSE_STRING) {
-		char *value = MBSTRG(internal_encoding_name);
-		_php_mb_ini_mbstring_internal_encoding_set(value, value ? strlen(value): 0);
-	}
-
 	if (!MBSTRG(encoding_translation)) {
 		php_default_treat_data(arg, str, destArray);
 		return;
diff --git a/ext/mbstring/mbstring.c b/ext/mbstring/mbstring.c
index ee65b4107b..61e47630ef 100644
--- a/ext/mbstring/mbstring.c
+++ b/ext/mbstring/mbstring.c
@@ -615,34 +615,6 @@ ZEND_TSRMLS_CACHE_DEFINE()
 ZEND_GET_MODULE(mbstring)
 #endif
 
-static char *get_internal_encoding(void) {
-	if (PG(internal_encoding) && PG(internal_encoding)[0]) {
-		return PG(internal_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
-	}
-	return "";
-}
-
-static char *get_input_encoding(void) {
-	if (PG(input_encoding) && PG(input_encoding)[0]) {
-		return PG(input_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
-	}
-	return "";
-}
-
-static char *get_output_encoding(void) {
-	if (PG(output_encoding) && PG(output_encoding)[0]) {
-		return PG(output_encoding);
-	} else if (SG(default_charset)) {
-		return SG(default_charset);
-	}
-	return "";
-}
-
-
 /* {{{ allocators */
 static void *_php_mb_allocators_malloc(size_t sz)
 {
@@ -1289,77 +1261,70 @@ static PHP_INI_MH(OnUpdate_mbstring_detect_order)
 }
 /* }}} */
 
-/* {{{ static PHP_INI_MH(OnUpdate_mbstring_http_input) */
-static PHP_INI_MH(OnUpdate_mbstring_http_input)
-{
+static int _php_mb_ini_mbstring_http_input_set(const char *new_value, size_t new_value_length) {
 	const mbfl_encoding **list;
 	size_t size;
-
-	if (!new_value || !ZSTR_VAL(new_value)) {
-		if (MBSTRG(http_input_list)) {
-			pefree(MBSTRG(http_input_list), 1);
-		}
-		if (SUCCESS == php_mb_parse_encoding_list(get_input_encoding(), strlen(get_input_encoding())+1, &list, &size, 1)) {
-			MBSTRG(http_input_list) = list;
-			MBSTRG(http_input_list_size) = size;
-			return SUCCESS;
-		}
-		MBSTRG(http_input_list) = NULL;
-		MBSTRG(http_input_list_size) = 0;
-		return SUCCESS;
-	}
-
-	if (FAILURE == php_mb_parse_encoding_list(ZSTR_VAL(new_value), ZSTR_LEN(new_value), &list, &size, 1)) {
+	if (FAILURE == php_mb_parse_encoding_list(new_value, new_value_length, &list, &size, 1)) {
 		return FAILURE;
 	}
-
 	if (MBSTRG(http_input_list)) {
 		pefree(MBSTRG(http_input_list), 1);
 	}
 	MBSTRG(http_input_list) = list;
 	MBSTRG(http_input_list_size) = size;
+	return SUCCESS;
+}
 
+/* {{{ static PHP_INI_MH(OnUpdate_mbstring_http_input) */
+static PHP_INI_MH(OnUpdate_mbstring_http_input)
+{
 	if (stage & (PHP_INI_STAGE_ACTIVATE | PHP_INI_STAGE_RUNTIME)) {
 		php_error_docref("ref.mbstring", E_DEPRECATED, "Use of mbstring.http_input is deprecated");
 	}
 
-	return SUCCESS;
+	if (!new_value || !ZSTR_VAL(new_value)) {
+		const char *encoding = php_get_input_encoding();
+		MBSTRG(http_input_set) = 0;
+		_php_mb_ini_mbstring_http_input_set(encoding, strlen(encoding));
+		return SUCCESS;
+	}
+
+	MBSTRG(http_input_set) = 1;
+	return _php_mb_ini_mbstring_http_input_set(ZSTR_VAL(new_value), ZSTR_LEN(new_value));
 }
 /* }}} */
 
-/* {{{ static PHP_INI_MH(OnUpdate_mbstring_http_output) */
-static PHP_INI_MH(OnUpdate_mbstring_http_output)
-{
-	const mbfl_encoding *encoding;
-
-	if (new_value == NULL || ZSTR_LEN(new_value) == 0) {
-		encoding = mbfl_name2encoding(get_output_encoding());
-		if (!encoding) {
-			MBSTRG(http_output_encoding) = &mbfl_encoding_pass;
-			MBSTRG(current_http_output_encoding) = &mbfl_encoding_pass;
-			return SUCCESS;
-		}
-	} else {
-		encoding = mbfl_name2encoding(ZSTR_VAL(new_value));
-		if (!encoding) {
-			MBSTRG(http_output_encoding) = &mbfl_encoding_pass;
-			MBSTRG(current_http_output_encoding) = &mbfl_encoding_pass;
-			return FAILURE;
-		}
+static int _php_mb_ini_mbstring_http_output_set(const char *new_value) {
+	const mbfl_encoding *encoding = mbfl_name2encoding(new_value);
+	if (!encoding) {
+		return FAILURE;
 	}
+
 	MBSTRG(http_output_encoding) = encoding;
 	MBSTRG(current_http_output_encoding) = encoding;
+	return SUCCESS;
+}
 
+/* {{{ static PHP_INI_MH(OnUpdate_mbstring_http_output) */
+static PHP_INI_MH(OnUpdate_mbstring_http_output)
+{
 	if (stage & (PHP_INI_STAGE_ACTIVATE | PHP_INI_STAGE_RUNTIME)) {
 		php_error_docref("ref.mbstring", E_DEPRECATED, "Use of mbstring.http_output is deprecated");
 	}
 
-	return SUCCESS;
+	if (new_value == NULL || ZSTR_LEN(new_value) == 0) {
+		MBSTRG(http_output_set) = 0;
+		_php_mb_ini_mbstring_http_output_set(php_get_output_encoding());
+		return SUCCESS;
+	}
+
+	MBSTRG(http_output_set) = 1;
+	return _php_mb_ini_mbstring_http_output_set(ZSTR_VAL(new_value));
 }
 /* }}} */
 
 /* {{{ static _php_mb_ini_mbstring_internal_encoding_set */
-int _php_mb_ini_mbstring_internal_encoding_set(const char *new_value, size_t new_value_length)
+static int _php_mb_ini_mbstring_internal_encoding_set(const char *new_value, size_t new_value_length)
 {
 	const mbfl_encoding *encoding;
 
@@ -1395,20 +1360,13 @@ static PHP_INI_MH(OnUpdate_mbstring_internal_encoding)
 		return FAILURE;
 	}
 
-	if (stage & (PHP_INI_STAGE_STARTUP | PHP_INI_STAGE_SHUTDOWN | PHP_INI_STAGE_RUNTIME)) {
-		if (new_value && ZSTR_LEN(new_value)) {
-			return _php_mb_ini_mbstring_internal_encoding_set(ZSTR_VAL(new_value), ZSTR_LEN(new_value));
-		} else {
-			return _php_mb_ini_mbstring_internal_encoding_set(get_internal_encoding(), strlen(get_internal_encoding())+1);
-		}
+	if (new_value && ZSTR_LEN(new_value)) {
+		MBSTRG(internal_encoding_set) = 1;
+		return _php_mb_ini_mbstring_internal_encoding_set(ZSTR_VAL(new_value), ZSTR_LEN(new_value));
 	} else {
-		/* the corresponding mbstring globals needs to be set according to the
-		 * ini value in the later stage because it never falls back to the
-		 * default value if 1. no value for mbstring.internal_encoding is given,
-		 * 2. mbstring.language directive is processed in per-dir or runtime
-		 * context and 3. call to the handler for mbstring.language is done
-		 * after mbstring.internal_encoding is handled. */
-		return SUCCESS;
+		const char *encoding = php_get_internal_encoding();
+		MBSTRG(internal_encoding_set) = 0;
+		return _php_mb_ini_mbstring_internal_encoding_set(encoding, strlen(encoding));
 	}
 }
 /* }}} */
@@ -1532,6 +1490,24 @@ PHP_INI_BEGIN()
 PHP_INI_END()
 /* }}} */
 
+static void mbstring_internal_encoding_changed_hook() {
+	/* One of the internal_encoding / input_encoding / output_encoding ini settings changed. */
+	if (!MBSTRG(internal_encoding_set)) {
+		const char *encoding = php_get_internal_encoding();
+		_php_mb_ini_mbstring_internal_encoding_set(encoding, strlen(encoding));
+	}
+
+	if (!MBSTRG(http_output_set)) {
+		const char *encoding = php_get_output_encoding();
+		_php_mb_ini_mbstring_http_output_set(encoding);
+	}
+
+	if (!MBSTRG(http_input_set)) {
+		const char *encoding = php_get_input_encoding();
+		_php_mb_ini_mbstring_http_input_set(encoding, strlen(encoding));
+	}
+}
+
 /* {{{ module global initialize handler */
 static PHP_GINIT_FUNCTION(mbstring)
 {
@@ -1572,6 +1548,9 @@ ZEND_TSRMLS_CACHE_UPDATE();
 #endif
 	mbstring_globals->last_used_encoding_name = NULL;
 	mbstring_globals->last_used_encoding = NULL;
+	mbstring_globals->internal_encoding_set = 0;
+	mbstring_globals->http_output_set = 0;
+	mbstring_globals->http_input_set = 0;
 }
 /* }}} */
 
@@ -1603,6 +1582,11 @@ ZEND_TSRMLS_CACHE_UPDATE();
 
 	REGISTER_INI_ENTRIES();
 
+	/* We assume that we're the only user of the hook. */
+	ZEND_ASSERT(php_internal_encoding_changed == NULL);
+	php_internal_encoding_changed = mbstring_internal_encoding_changed_hook;
+	mbstring_internal_encoding_changed_hook();
+
 	/* This is a global handler. Should not be set in a per-request handler. */
 	sapi_register_treat_data(mbstr_treat_data);
 
@@ -1763,6 +1747,10 @@ PHP_RSHUTDOWN_FUNCTION(mbstring)
 		MBSTRG(last_used_encoding_name) = NULL;
 	}
 
+	MBSTRG(internal_encoding_set) = 0;
+	MBSTRG(http_output_set) = 0;
+	MBSTRG(http_input_set) = 0;
+
 #if HAVE_MBREGEX
 	PHP_RSHUTDOWN(mb_regex) (INIT_FUNC_ARGS_PASSTHRU);
 #endif
@@ -1846,6 +1834,7 @@ PHP_FUNCTION(mb_internal_encoding)
 			RETURN_FALSE;
 		} else {
 			MBSTRG(current_internal_encoding) = encoding;
+			MBSTRG(internal_encoding_set) = 1;
 			RETURN_TRUE;
 		}
 	}
@@ -1969,6 +1958,7 @@ PHP_FUNCTION(mb_http_output)
 			php_error_docref(NULL, E_WARNING, "Unknown encoding \"%s\"", name);
 			RETURN_FALSE;
 		} else {
+			MBSTRG(http_output_set) = 1;
 			MBSTRG(current_http_output_encoding) = encoding;
 			RETURN_TRUE;
 		}
diff --git a/ext/mbstring/mbstring.h b/ext/mbstring/mbstring.h
index cd882c1c03..5a713e5496 100644
--- a/ext/mbstring/mbstring.h
+++ b/ext/mbstring/mbstring.h
@@ -130,9 +130,6 @@ MBSTRING_API size_t php_mb_mbchar_bytes(const char *s);
 MBSTRING_API size_t php_mb_stripos(int mode, const char *old_haystack, size_t old_haystack_len, const char *old_needle, size_t old_needle_len, zend_long offset, zend_string *from_encoding);
 MBSTRING_API int php_mb_check_encoding(const char *input, size_t length, const char *enc);
 
-/* internal use only */
-int _php_mb_ini_mbstring_internal_encoding_set(const char *new_value, size_t new_value_length);
-
 ZEND_BEGIN_MODULE_GLOBALS(mbstring)
 	char *internal_encoding_name;
 	const mbfl_encoding *internal_encoding;
@@ -169,6 +166,10 @@ ZEND_BEGIN_MODULE_GLOBALS(mbstring)
 #endif
 	zend_string *last_used_encoding_name;
 	const mbfl_encoding *last_used_encoding;
+	/* Whether an explicit internal_encoding / http_output / http_input encoding was set. */
+	zend_bool internal_encoding_set;
+	zend_bool http_output_set;
+	zend_bool http_input_set;
 ZEND_END_MODULE_GLOBALS(mbstring)
 
 #define MB_OVERLOAD_MAIL 1
diff --git a/ext/mbstring/tests/ini_encoding2.phpt b/ext/mbstring/tests/ini_encoding2.phpt
index f3728486ae..64cc23ec91 100644
--- a/ext/mbstring/tests/ini_encoding2.phpt
+++ b/ext/mbstring/tests/ini_encoding2.phpt
@@ -50,7 +50,7 @@ string(6) "EUC-JP"
 string(0) ""
 string(0) ""
 string(0) ""
-string(5) "UTF-8"
+string(6) "EUC-JP"
 string(0) ""
 string(0) ""
 Setting INI
diff --git a/ext/mbstring/tests/internal_encoding.phpt b/ext/mbstring/tests/internal_encoding.phpt
new file mode 100644
index 0000000000..3d097ac79c
--- /dev/null
+++ b/ext/mbstring/tests/internal_encoding.phpt
@@ -0,0 +1,66 @@
+--TEST--
+Check that "internal_encoding" ini is picked up by mbstring
+--INI--
+internal_encoding=iso-8859-1
+--FILE--
+<?php
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+ini_set('mbstring.internal_encoding', 'utf-8');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+// mbstring.internal_encoding is set, this has no effect
+ini_set('internal_encoding', 'iso-8859-2');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+// mbstring.internal_encoding is unset, pick up internal_encoding again
+ini_set('mbstring.internal_encoding', '');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+mb_internal_encoding('utf-8');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+// mb_internal_encoding() is set, this has no effect
+ini_set('internal_encoding', 'iso-8859-3');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+// mbstring.internal_encoding is unset, pick up internal_encoding again
+ini_set('mbstring.internal_encoding', '');
+
+var_dump(mb_internal_encoding());
+var_dump(mb_strlen("\xc3\xb6"));
+
+?>
+--EXPECTF--
+string(10) "ISO-8859-1"
+int(2)
+
+Deprecated: ini_set(): Use of mbstring.internal_encoding is deprecated in %s on line %d
+string(5) "UTF-8"
+int(1)
+string(5) "UTF-8"
+int(1)
+
+Deprecated: ini_set(): Use of mbstring.internal_encoding is deprecated in %s on line %d
+string(10) "ISO-8859-2"
+int(2)
+string(5) "UTF-8"
+int(1)
+string(5) "UTF-8"
+int(1)
+
+Deprecated: ini_set(): Use of mbstring.internal_encoding is deprecated in %s on line %d
+string(10) "ISO-8859-3"
+int(2)
diff --git a/ext/mbstring/tests/mb_internal_encoding_basic2.phpt b/ext/mbstring/tests/mb_internal_encoding_basic2.phpt
index 8090b47be5..99b92027e9 100644
--- a/ext/mbstring/tests/mb_internal_encoding_basic2.phpt
+++ b/ext/mbstring/tests/mb_internal_encoding_basic2.phpt
@@ -47,7 +47,7 @@ string(10) "ISO-8859-1"
 string(0) ""
 string(0) ""
 string(0) ""
-string(5) "UTF-8"
+string(10) "ISO-8859-1"
 bool(true)
 string(5) "UTF-8"
 Done
diff --git a/main/main.c b/main/main.c
index 5eb34b7fa4..f021f22af5 100644
--- a/main/main.c
+++ b/main/main.c
@@ -578,12 +578,44 @@ static PHP_INI_DISP(display_errors_mode)
 }
 /* }}} */
 
+PHPAPI const char *php_get_internal_encoding() {
+	if (PG(internal_encoding) && PG(internal_encoding)[0]) {
+		return PG(internal_encoding);
+	} else if (SG(default_charset)) {
+		return SG(default_charset);
+	}
+	return "";
+}
+
+PHPAPI const char *php_get_input_encoding() {
+	if (PG(input_encoding) && PG(input_encoding)[0]) {
+		return PG(input_encoding);
+	} else if (SG(default_charset)) {
+		return SG(default_charset);
+	}
+	return "";
+}
+
+PHPAPI const char *php_get_output_encoding() {
+	if (PG(output_encoding) && PG(output_encoding)[0]) {
+		return PG(output_encoding);
+	} else if (SG(default_charset)) {
+		return SG(default_charset);
+	}
+	return "";
+}
+
+PHPAPI void (*php_internal_encoding_changed)(void) = NULL;
+
 /* {{{ PHP_INI_MH
  */
 static PHP_INI_MH(OnUpdateDefaultCharset)
 {
 	if (new_value) {
 		OnUpdateString(entry, new_value, mh_arg1, mh_arg2, mh_arg3, stage);
+		if (php_internal_encoding_changed) {
+			php_internal_encoding_changed();
+		}
 #ifdef PHP_WIN32
 		php_win32_cp_do_update(ZSTR_VAL(new_value));
 #endif
@@ -598,6 +630,9 @@ static PHP_INI_MH(OnUpdateInternalEncoding)
 {
 	if (new_value) {
 		OnUpdateString(entry, new_value, mh_arg1, mh_arg2, mh_arg3, stage);
+		if (php_internal_encoding_changed) {
+			php_internal_encoding_changed();
+		}
 #ifdef PHP_WIN32
 		php_win32_cp_do_update(ZSTR_VAL(new_value));
 #endif
@@ -612,6 +647,9 @@ static PHP_INI_MH(OnUpdateInputEncoding)
 {
 	if (new_value) {
 		OnUpdateString(entry, new_value, mh_arg1, mh_arg2, mh_arg3, stage);
+		if (php_internal_encoding_changed) {
+			php_internal_encoding_changed();
+		}
 #ifdef PHP_WIN32
 		php_win32_cp_do_update(NULL);
 #endif
@@ -626,6 +664,9 @@ static PHP_INI_MH(OnUpdateOutputEncoding)
 {
 	if (new_value) {
 		OnUpdateString(entry, new_value, mh_arg1, mh_arg2, mh_arg3, stage);
+		if (php_internal_encoding_changed) {
+			php_internal_encoding_changed();
+		}
 #ifdef PHP_WIN32
 		php_win32_cp_do_update(NULL);
 #endif
diff --git a/main/php.h b/main/php.h
index 48b4633879..be9917922a 100644
--- a/main/php.h
+++ b/main/php.h
@@ -371,6 +371,11 @@ PHPAPI int php_mergesort(void *base, size_t nmemb, size_t size, int (*cmp)(const
 PHPAPI void php_register_pre_request_shutdown(void (*func)(void *), void *userdata);
 PHPAPI void php_com_initialize(void);
 PHPAPI char *php_get_current_user(void);
+
+PHPAPI const char *php_get_internal_encoding(void);
+PHPAPI const char *php_get_input_encoding(void);
+PHPAPI const char *php_get_output_encoding(void);
+PHPAPI extern void (*php_internal_encoding_changed)(void);
 END_EXTERN_C()
 
 /* PHP-named Zend macro wrappers */
-- 
2.50.1