RT3479: Add UTF8 support to BIO_read_filename()

If we use BIO_new_file(), on Windows it'll jump through hoops to work
around their unusual charset/Unicode handling. it'll convert a UTF-8
filename to UCS-16LE and attempt to use _wfopen().

If you use BIO_read_filename(), it doesn't do this. Shouldn't it be
consistent?

It would certainly be nice if SSL_use_certificate_chain_file() worked.

Also made BIO_C_SET_FILENAME work (rsalz)
Signed-off-by: NRich Salz <rsalz@akamai.com>
Reviewed-by: NAndy Polyakov <appro@openssl.org>

crypto/bio/bss_file.c

@@ -115,9 +115,8 @@ static BIO_METHOD methods_filep = {
     NULL,
 };
 
-BIO *BIO_new_file(const char *filename, const char *mode)
+static FILE *file_fopen(const char *filename, const char *mode)
 {
-    BIO *ret;
     FILE *file = NULL;
 
 #  if defined(_WIN32) && defined(CP_UTF8)
@@ -164,6 +163,14 @@ BIO *BIO_new_file(const char *filename, const char *mode)
 #  else
     file = fopen(filename, mode);
 #  endif
+    return (file);
+}
+
+BIO *BIO_new_file(const char *filename, const char *mode)
+{
+    BIO  *ret;
+    FILE *file = file_fopen(filename, mode);
+
     if (file == NULL) {
         SYSerr(SYS_F_FOPEN, get_last_sys_error());
         ERR_add_error_data(5, "fopen('", filename, "','", mode, "')");
@@ -386,7 +393,7 @@ static long file_ctrl(BIO *b, int cmd, long num, void *ptr)
         else
             strcat(p, "t");
 #  endif
-        fp = fopen(ptr, p);
+        fp = file_fopen(ptr, p);
         if (fp == NULL) {
             SYSerr(SYS_F_FOPEN, get_last_sys_error());
             ERR_add_error_data(5, "fopen('", ptr, "','", p, "')");