Bug#564722: htdigest -c should bail if the target digest file exists

["Jean-Michel Vourgère" <jmv_deb@nirgal.com>]

man page says:
-c     Create  the  passwdfile.  If  passwdfile  already  exists, it is
              deleted first.

And from older version, one can guess file was effectively truncated: fopen("w").
https://svn.apache.org/viewvc/httpd/httpd/trunk/support/htdigest.c?r1=85063&r2=85064
(That was 11 years ago...)

So I suggest we just to add APR_TRUNCATE to apr_file_open(APR_WRITE | APR_CREATE) to keep the documented behavior.

On the other hand, bailing out really makes sense to me.

Issue should be discussed upstream.

I'm attaching a fix for the "inconsistent behaviour" bug.

--- support/htdigest.c	2012-02-03 16:18:17.000000000 +0100
+++ /home/nirgal/htdigest.c	2012-02-03 16:16:42.000000000 +0100
@@ -212,7 +212,7 @@
     if (argc == 5) {
         if (strcmp(argv[1], "-c"))
             usage();
-        rv = apr_file_open(&f, argv[2], APR_WRITE | APR_CREATE,
+        rv = apr_file_open(&f, argv[2], APR_WRITE | APR_CREATE | APR_TRUNCATE,
                            APR_OS_DEFAULT, cntxt);
         if (rv != APR_SUCCESS) {
             char errmsg[120];