nss: Add tst-nss-files-hosts-long test [BZ #21915]

When the /etc/hosts file has a line longer than 1028
characters getent ahostsv4 and ahostsv6 will fail.

This test performs a getent call on a /etc/hosts file that contains
a very long line (greater than 1028) using the test-in-container
framework.

3 files changed, 55 insertions, 1 deletions

diff --git a/nss/Makefile b/nss/Makefile
index e66e01d45a..a8caa8af38 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -60,7 +60,8 @@ tests			= test-netdb test-digits-dots tst-nss-getpwent bug17079 \
 xtests			= bug-erange
 
 tests-container = \
-			  tst-nss-test3
+			  tst-nss-test3 \
+			  tst-nss-files-hosts-long
 
 # Tests which need libdl
 ifeq (yes,$(build-shared))
diff --git a/nss/tst-nss-files-hosts-long.c b/nss/tst-nss-files-hosts-long.c
new file mode 100644
index 0000000000..32f849e481
--- /dev/null
+++ b/nss/tst-nss-files-hosts-long.c
@@ -0,0 +1,45 @@
+/* Test getent doesn't fail with long /etc/hosts lines (Bug 21915).
+   Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+/* This test runs getent twice to parse a /etc/hosts with a very
+   long line. Prior to fixing this parser this would crash getent.  */
+
+#include <stdlib.h>
+#include <nss.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+  int ret;
+
+  /* Run getent to fetch the IPv4 address for host test4.
+     This forces /etc/hosts to be parsed.  */
+  ret = system("getent ahostsv4 test4");
+  if (ret != 0)
+    FAIL_EXIT1("ahostsv4 failed");
+
+  /* Likewise for IPv6.  */
+  ret = system("getent ahostsv6 test6");
+  if (ret != 0)
+    FAIL_EXIT1("ahostsv6 failed");
+
+  exit (0);
+}
+
+#include <support/test-driver.c>
diff --git a/nss/tst-nss-files-hosts-long.root/etc/hosts b/nss/tst-nss-files-hosts-long.root/etc/hosts
new file mode 100644
index 0000000000..db33f42f14
--- /dev/null
+++ b/nss/tst-nss-files-hosts-long.root/etc/hosts
@@ -0,0 +1,8 @@
+# This data is valid and short.
+192.168.1.1 test4.example.com test4
+::2 test6.example.com test6
+
+# Long line data is arbitrary and not specifically chosen.
+# They key issue is that it should be long to trigger the parser failure.
+192.168.2.2  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.ru
+#aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa