Use libnss_files.so for tests posix/bug-ga2 and resolv/tst-leaks2 [BZ #26821]

The tests posix/bug-ga2-mem and resolv/mtrace-tst-leaks2 are failing on
fedora 33 as mtrace reports memory leaks.

The /etc/nsswitch.conf differs between
Fedora 32: hosts:      files dns myhostname
Fedora 33: hosts:      files resolve [!UNAVAIL=return] myhostname dns

Therefore /lib64/libnss_resolve.so.2 (from systemd) and the dependencies
libgcc_s.so.1 and libpthread.so.0 are loaded.

Usually all malloc'ed resources from getaddrinfo / gethostbyname are freed
and the libraries are dlclose'd in nss/nsswitch.c:libc_freeres_fn (free_mem).
Unfortunately, /lib64/libnss_resolve.so.2 is marked with DF_1_NODELETE.
As this library is not unmapped, you'll see "Memory not freed".

Therefore those tests are now only relying on libnss_files.so by making
them test-container tests and providing the required configuration files.

By moving the tests to tests-container, those are now running with
"make check".  Therefore the mtrace part of the tests are also moved
from "make xcheck" to "make check".

bug-ga2.c is now using test-driver.c in order to support WAIT_FOR_DEBUGGER
environment variable.

posix/Makefile

@@ -106,7 +106,8 @@ tests		:= test-errno tstgetopt testfnm runtests runptests \
 tests-internal	:= bug-regex5 bug-regex20 bug-regex33 \
 		   tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 \
 		   tst-glob_lstat_compat tst-spawn4-compat
-xtests		:= bug-ga2 tst-getaddrinfo4 tst-getaddrinfo5
+tests-container := bug-ga2
+xtests		:= tst-getaddrinfo4 tst-getaddrinfo5
 ifeq (yes,$(build-shared))
 test-srcs	:= globtest
 tests           += wordexp-test tst-exec tst-spawn tst-spawn2 tst-spawn3
@@ -153,8 +154,7 @@ tests-special += $(objpfx)bug-regex2-mem.out $(objpfx)bug-regex14-mem.out \
 		 $(objpfx)tst-boost-mem.out $(objpfx)tst-getconf.out \
 		 $(objpfx)bug-glob2-mem.out $(objpfx)tst-vfork3-mem.out \
 		 $(objpfx)tst-fnmatch-mem.out $(objpfx)bug-regex36-mem.out \
-		 $(objpfx)tst-glob-tilde-mem.out
-xtests-special += $(objpfx)bug-ga2-mem.out
+		 $(objpfx)tst-glob-tilde-mem.out $(objpfx)bug-ga2-mem.out
 endif
 
 include ../Rules

posix/bug-ga2.c

@@ -3,9 +3,10 @@
 #include <netdb.h>
 #include <stdio.h>
 #include <string.h>
+#include <support/check.h>
 
-int
-main (void)
+static int
+do_test (void)
 {
   struct addrinfo hints, *res;
   int i, ret;
@@ -20,11 +21,11 @@ main (void)
       ret = getaddrinfo ("www.gnu.org", "http", &hints, &res);
 
       if (ret)
-	{
-	  printf ("%s\n", gai_strerror (ret));
-	  return 1;
-	}
+	FAIL_EXIT1 ("%s\n", gai_strerror (ret));
+
       freeaddrinfo (res);
     }
   return 0;
 }
+
+#include <support/test-driver.c>

posix/bug-ga2.root/etc/hosts

@@ -0,0 +1 @@
+192.0.2.1 www.gnu.org

posix/bug-ga2.root/etc/nsswitch.conf

@@ -0,0 +1,2 @@
+services: files
+hosts:    files

posix/bug-ga2.root/etc/services

@@ -0,0 +1 @@
+http 80/tcp

resolv/Makefile

@@ -32,7 +32,7 @@ routines := herror inet_addr inet_ntop inet_pton nsap_addr res_init \
 	    resolv_context resolv_conf
 
 tests = tst-aton tst-leaks tst-inet_ntop
-xtests = tst-leaks2
+tests-container = tst-leaks2
 
 tests-internal += tst-inet_aton_exact
 
@@ -125,9 +125,8 @@ endif
 
 ifeq ($(run-built-tests),yes)
 ifneq (no,$(PERL))
-tests-special += $(objpfx)mtrace-tst-leaks.out
-xtests-special += $(objpfx)mtrace-tst-leaks2.out
-tests-special += $(objpfx)mtrace-tst-resolv-res_ninit.out
+tests-special += $(objpfx)mtrace-tst-leaks.out $(objpfx)mtrace-tst-leaks2.out \
+		 $(objpfx)mtrace-tst-resolv-res_ninit.out
 endif
 endif
 

resolv/tst-leaks2.c

@@ -21,6 +21,7 @@
 #include <mcheck.h>
 #include <netdb.h>
 #include <resolv.h>
+#include <support/check.h>
 
 static int
 do_test (void)
@@ -28,8 +29,9 @@ do_test (void)
   mtrace ();
   for (int i = 0; i < 20; ++i)
     {
-      res_init ();
-      gethostbyname ("www.gnu.org");
+      TEST_VERIFY_EXIT (res_init () == 0);
+      if (gethostbyname ("www.gnu.org") == NULL)
+	FAIL_EXIT1 ("%s\n", hstrerror (h_errno));
     }
   return 0;
 }

resolv/tst-leaks2.root/etc/hosts

@@ -0,0 +1 @@
+192.0.2.1 www.gnu.org

resolv/tst-leaks2.root/etc/nsswitch.conf

@@ -0,0 +1 @@
+hosts: files