commit 307d04334d516bb180f484a2b283f97310bfee66

Author: Florian Weimer <fweimer@redhat.com>

Date:   Thu Sep 20 12:03:01 2018 +0200

    misc: New test misc/tst-gethostid

    The empty /etc/hosts file used to trigger bug 23679.

    (cherry picked from commit db9a8ad4ff3fc58e3773a9a4d0cabe3c1bc9c94c)

diff --git a/misc/Makefile b/misc/Makefile

index b7be2bc19a6f7ed5..c9f81515ac9aef2c 100644

--- a/misc/Makefile

+++ b/misc/Makefile

@@ -86,6 +86,11 @@ tests := tst-dirname tst-tsearch tst-fdset tst-efgcvt tst-mntent tst-hsearch \

 	 tst-preadvwritev tst-preadvwritev64 tst-makedev tst-empty \

 	 tst-preadvwritev2 tst-preadvwritev64v2

+# Tests which need libdl.

+ifeq (yes,$(build-shared))

+tests += tst-gethostid

+endif

+

 tests-internal := tst-atomic tst-atomic-long tst-allocate_once

 tests-static := tst-empty

@@ -145,3 +150,5 @@ tst-allocate_once-ENV = MALLOC_TRACE=$(objpfx)tst-allocate_once.mtrace

 $(objpfx)tst-allocate_once-mem.out: $(objpfx)tst-allocate_once.out

 	$(common-objpfx)malloc/mtrace $(objpfx)tst-allocate_once.mtrace > $@; \

 	$(evaluate-test)

+

+$(objpfx)tst-gethostid: $(libdl)

diff --git a/misc/tst-gethostid.c b/misc/tst-gethostid.c

new file mode 100644

index 0000000000000000..1490aaf3f517ff1d

--- /dev/null

+++ b/misc/tst-gethostid.c

@@ -0,0 +1,108 @@

+/* Basic test for gethostid.

+   Copyright (C) 2018 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; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#include <gnu/lib-names.h>

+#include <nss.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+#include <support/namespace.h>

+#include <support/support.h>

+#include <support/temp_file.h>

+#include <support/xdlfcn.h>

+#include <support/xstdio.h>

+#include <support/xunistd.h>

+#include <unistd.h>

+

+/* Initial test is run outside a chroot, to increase the likelihood of

+   success.  */

+static void

+outside_chroot (void *closure)

+{

+  long id = gethostid ();

+  printf ("info: host ID outside chroot: 0x%lx\n", id);

+}

+

+/* The same, but this time perform a chroot operation.  */

+static void

+in_chroot (void *closure)

+{

+  const char *chroot_path = closure;

+  xchroot (chroot_path);

+  long id = gethostid ();

+  printf ("info: host ID in chroot: 0x%lx\n", id);

+}

+

+static int

+do_test (void)

+{

+  support_isolate_in_subprocess (outside_chroot, NULL);

+

+  /* Now run the test inside a chroot.  */

+  support_become_root ();

+  if (!support_can_chroot ())

+    /* Cannot perform further tests.  */

+    return 0;

+

+  /* Only use nss_files.  */

+  __nss_configure_lookup ("hosts", "files");

+

+  /* Load the DSO outside of the chroot.  */

+  xdlopen (LIBNSS_FILES_SO, RTLD_LAZY);

+

+  char *chroot_dir = support_create_temp_directory ("tst-gethostid-");

+  support_isolate_in_subprocess (in_chroot, chroot_dir);

+

+  /* Tests with /etc/hosts in the chroot.  */

+  {

+    char *path = xasprintf ("%s/etc", chroot_dir);

+    add_temp_file (path);

+    xmkdir (path, 0777);

+    free (path);

+    path = xasprintf ("%s/etc/hosts", chroot_dir);

+    add_temp_file (path);

+

+    FILE *fp = xfopen (path, "w");

+    xfclose (fp);

+    printf ("info: chroot test with an empty /etc/hosts file\n");

+    support_isolate_in_subprocess (in_chroot, chroot_dir);

+

+    char hostname[1024];

+    int ret = gethostname (hostname, sizeof (hostname));

+    if (ret < 0)

+      printf ("warning: invalid result from gethostname: %d\n", ret);

+    else if (strlen (hostname) == 0)

+      puts ("warning: gethostname returned empty string");

+    else

+      {

+        printf ("info: chroot test with IPv6 address in /etc/hosts for: %s\n",

+                hostname);

+        fp = xfopen (path, "w");

+        /* Use an IPv6 address to induce another lookup failure.  */

+        fprintf (fp, "2001:db8::1 %s\n", hostname);

+        xfclose (fp);

+        support_isolate_in_subprocess (in_chroot, chroot_dir);

+      }

+    free (path);

+  }

+  free (chroot_dir);

+

+  return 0;

+}

+

+#include <support/test-driver.c>