Merge branch '2166-bind-9-16-7-trap-divide-error-v9_16' into 'v9_16'

Resolve "bind 9.16.7 trap divide error"

See merge request isc-projects/bind9!4152

CHANGES

@@ -1,3 +1,6 @@
+5506.	[bug]		Properly handle failed sysconf() calls, so we don't
+			report invalid memory size. [GL #2166]
+
 5505.	[bug]		Updating contents of a mixed-case RPZ could cause some
 			rules to be ignored. [GL #2169]
 

doc/notes/notes-current.rst

@@ -42,3 +42,7 @@ Bug Fixes
 - Updating contents of an RPZ zone which contained names spelled using
   varying letter case could cause some processing rules in that RPZ zone
   to be erroneously ignored. [GL #2169]
+
+- `named` would report invalid memory size when running in an environment
+  that doesn't properly report number of available memory pages or pagesize.
+  [GL #2166]

lib/isc/unix/meminfo.c

@@ -35,7 +35,14 @@ isc_meminfo_totalphys(void) {
 #endif /* if defined(CTL_HW) && (defined(HW_PHYSMEM64) || defined(HW_MEMSIZE)) \
 	* */
 #if defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
-	return ((size_t)(sysconf(_SC_PHYS_PAGES) * sysconf(_SC_PAGESIZE)));
+	long pages = sysconf(_SC_PHYS_PAGES);
+	long pagesize = sysconf(_SC_PAGESIZE);
+
+	if (pages == -1 || pagesize == -1) {
+		return (0);
+	}
+
+	return ((size_t)pages * pagesize);
 #endif /* if defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE) */
 	return (0);
 }