Check if the payloadformat really is "cpio", fail with an error
message if it is not. Use a different message for the "drpm"
delta-rpm format. rh#140052

Upstream proposes a different approach, patching the "Requires"
list, which the current deltarpm implementation can't do, because
it uses a verbatim copy of the original header. Sigh.

I still believe that rpm should check for known formats, i.e.
now that rpm understands ustar it should insist that the format
is either "cpio" or "ustar".

--- ./lib/rpminstall.c.orig	2005-12-14 21:01:09.000000000 +0000
+++ ./lib/rpminstall.c	2005-12-15 14:47:35.000000000 +0000
@@ -470,6 +470,7 @@ if (fileURL[0] == '=') {
 	 eiu->fnp++, eiu->prevx++)
     {
 	const char * fileName;
+	const char * payloadformat;
 
 	rpmMessage(RPMMESS_DEBUG, "============== %s\n", *eiu->fnp);
 	(void) urlPath(*eiu->fnp, &fileName);
@@ -510,6 +511,17 @@ if (fileURL[0] == '=') {
 	    /*@switchbreak@*/ break;
 	}
 
+	payloadformat = 0;
+	if (!headerGetEntry(eiu->h, RPMTAG_PAYLOADFORMAT, NULL, (void **)&payloadformat, NULL))
+	    payloadformat = 0;
+	if (payloadformat && strcmp(payloadformat, "cpio") != 0) {
+	    if (!strcmp(payloadformat, "drpm"))
+		rpmMessage(RPMMESS_ERROR, _("%s is a deltarpm, create a real rpm from it first!\n"), *eiu->fnp);
+	    else
+		rpmMessage(RPMMESS_ERROR, _("%s contains no cpio payload\n"), *eiu->fnp);
+	    eiu->numFailed++; *eiu->fnp = NULL;
+	    continue;
+	}
 	eiu->isSource = headerIsEntry(eiu->h, RPMTAG_SOURCEPACKAGE);
 
 	if (eiu->isSource) {