in write_file(), properly handle filenames that contain nulls

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@3975 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

src/files.c

@@ -1275,7 +1275,7 @@ int write_file(const char *name, FILE *f_open, bool tmp, append_type
     int retval = -1;
 	/* Instead of returning in this function, you should always
 	 * merely set retval and then goto cleanup_and_exit. */
-    size_t lineswritten = 0;
+    size_t name_len, lineswritten = 0;
     const filestruct *fileptr = openfile->fileage;
     int fd;
 	/* The file descriptor we use. */
@@ -1310,8 +1310,18 @@ int write_file(const char *name, FILE *f_open, bool tmp, append_type
     if (!tmp)
 	titlebar(NULL);
 
+    name_len = strlen(name);
+
+    /* Convert newlines to nulls, just before we get the real
+     * filename. */
+    sunder(name);
+
     realname = real_dir_from_tilde(name);
 
+    /* Convert nulls to newlines.  name_len is the string's real
+     * length. */
+    unsunder(name, name_len);
+
 #ifndef DISABLE_OPERATINGDIR
     /* If we're writing a temporary file, we're probably going outside
      * the operating directory, so skip the operating directory test. */