Fix longstanding mb/wc functions segfault if error occurse

inside _<encoding>_init().
Currently _EUC_init() only was affected.

1 files changed, 39 insertions, 29 deletions

diff --git a/lib/libc/locale/setrunelocale.c b/lib/libc/locale/setrunelocale.c
index b4820bbedf5c..36d28946e3b4 100644
--- a/lib/libc/locale/setrunelocale.c
+++ b/lib/libc/locale/setrunelocale.c
@@ -51,15 +51,6 @@ extern _RuneLocale	*_Read_RuneMagi(FILE *);
 
 static int		__setrunelocale(const char *);
 
-static void convinit(void)
-{
-	__mbrtowc = NULL;
-	__mbsinit = NULL;
-	__mbsnrtowcs = __mbsnrtowcs_std;
-	__wcrtomb = NULL;
-	__wcsnrtombs = __wcsnrtombs_std;
-}
-
 static int
 __setrunelocale(const char *encoding)
 {
@@ -67,6 +58,16 @@ __setrunelocale(const char *encoding)
 	char name[PATH_MAX];
 	_RuneLocale *rl;
 	int saverr, ret;
+	size_t (*old__mbrtowc)(wchar_t * __restrict,
+	    const char * __restrict, size_t, mbstate_t * __restrict);
+	size_t (*old__wcrtomb)(char * __restrict, wchar_t,
+	    mbstate_t * __restrict);
+	int (*old__mbsinit)(const mbstate_t *);
+	size_t (*old__mbsnrtowcs)(wchar_t * __restrict,
+	    const char ** __restrict, size_t, size_t, mbstate_t * __restrict);
+	size_t (*old__wcsnrtombs)(char * __restrict,
+	    const wchar_t ** __restrict, size_t, size_t,
+	    mbstate_t * __restrict);
 	static char ctype_encoding[ENCODING_LEN + 1];
 	static _RuneLocale *CachedRuneLocale;
 	static int Cached__mb_cur_max;
@@ -126,36 +127,39 @@ __setrunelocale(const char *encoding)
 	}
 	(void)fclose(fp);
 
+	old__mbrtowc = __mbrtowc;
+	old__mbsinit = __mbsinit;
+	old__mbsnrtowcs = __mbsnrtowcs;
+	old__wcrtomb = __wcrtomb;
+	old__wcsnrtombs = __wcsnrtombs;
+
+	__mbrtowc = NULL;
+	__mbsinit = NULL;
+	__mbsnrtowcs = __mbsnrtowcs_std;
+	__wcrtomb = NULL;
+	__wcsnrtombs = __wcsnrtombs_std;
+
 	rl->__sputrune = NULL;
 	rl->__sgetrune = NULL;
-	if (strcmp(rl->__encoding, "NONE") == 0) {
-		convinit();
+	if (strcmp(rl->__encoding, "NONE") == 0)
 		ret = _none_init(rl);
-	} else if (strcmp(rl->__encoding, "ASCII") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "ASCII") == 0)
 		ret = _ascii_init(rl);
-	} else if (strcmp(rl->__encoding, "UTF-8") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "UTF-8") == 0)
 		ret = _UTF8_init(rl);
-	} else if (strcmp(rl->__encoding, "EUC") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "EUC") == 0)
 		ret = _EUC_init(rl);
-	} else if (strcmp(rl->__encoding, "GB18030") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "GB18030") == 0)
  		ret = _GB18030_init(rl);
-	} else if (strcmp(rl->__encoding, "GB2312") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "GB2312") == 0)
 		ret = _GB2312_init(rl);
-	} else if (strcmp(rl->__encoding, "GBK") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "GBK") == 0)
 		ret = _GBK_init(rl);
-	} else if (strcmp(rl->__encoding, "BIG5") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "BIG5") == 0)
 		ret = _BIG5_init(rl);
-	} else if (strcmp(rl->__encoding, "MSKanji") == 0) {
-		convinit();
+	else if (strcmp(rl->__encoding, "MSKanji") == 0)
 		ret = _MSKanji_init(rl);
-	} else
+	else
 		ret = EFTYPE;
 
 	if (ret == 0) {
@@ -174,8 +178,14 @@ __setrunelocale(const char *encoding)
 		Cached__wcrtomb = __wcrtomb;
 		Cached__wcsnrtombs = __wcsnrtombs;
 		(void)strcpy(ctype_encoding, encoding);
-	} else
+	} else {
+		__mbrtowc = old__mbrtowc;
+		__mbsinit = old__mbsinit;
+		__mbsnrtowcs = old__mbsnrtowcs;
+		__wcrtomb = old__wcrtomb;
+		__wcsnrtombs = old__wcsnrtombs;
 		free(rl);
+	}
 
 	return (ret);
 }