commit 2714c5f3c95f90977167c1d21326d907fb76b419

Author: Florian Weimer <fweimer@redhat.com>

Date:   Fri Jun 2 15:50:36 2017 +0200

    resolv: Tests for various versions of res_init

diff --git a/resolv/Makefile b/resolv/Makefile

index d41fd4603d7b7d77..0ebb2af795c6fb7b 100644

--- a/resolv/Makefile

+++ b/resolv/Makefile

@@ -57,6 +57,11 @@ ifeq (yes,$(build-shared))

 tests += \

   tst-resolv-canonname \

+# uses DEPRECATED_RES_USE_INET6 from <resolv-internal.h>.

+tests += \

+  tst-resolv-res_init \

+  tst-resolv-res_init-thread \

+

 endif

 # This test sends millions of packets and is rather slow.

@@ -136,6 +141,9 @@ $(objpfx)tst-res_use_inet6: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-basic: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-edns: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-network: $(objpfx)libresolv.so $(shared-thread-library)

+$(objpfx)tst-resolv-res_init: $(libdl) $(objpfx)libresolv.so

+$(objpfx)tst-resolv-res_init-thread: $(libdl) $(objpfx)libresolv.so \

+  $(shared-thread-library)

 $(objpfx)tst-resolv-qtypes: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-search: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-canonname: \

diff --git a/resolv/tst-resolv-res_init-skeleton.c b/resolv/tst-resolv-res_init-skeleton.c

new file mode 100644

index 0000000000000000..1d2c475c4b233131

--- /dev/null

+++ b/resolv/tst-resolv-res_init-skeleton.c

@@ -0,0 +1,601 @@

+/* Test parsing of /etc/resolv.conf.  Genric version.

+   Copyright (C) 2017 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/>.  */

+

+/* Before including this file, TEST_THREAD has to be defined to 0 or

+   1, depending on whether the threading tests should be compiled

+   in.  */

+

+#include <arpa/inet.h>

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

+#include <netdb.h>

+#include <resolv/resolv-internal.h> /* For DEPRECATED_RES_USE_INET6.  */

+#include <stdio.h>

+#include <stdlib.h>

+#include <support/capture_subprocess.h>

+#include <support/check.h>

+#include <support/namespace.h>

+#include <support/run_diff.h>

+#include <support/support.h>

+#include <support/temp_file.h>

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

+#include <support/xstdio.h>

+#include <support/xunistd.h>

+

+#if TEST_THREAD

+# include <support/xthread.h>

+#endif

+

+/* This is the host name used to ensure predictable behavior of

+   res_init.  */

+static const char *const test_hostname = "www.example.com";

+

+/* Path to the test root directory.  */

+static char *path_chroot;

+

+/* Path to resolv.conf under path_chroot (outside the chroot).  */

+static char *path_resolv_conf;

+

+static void

+prepare (int argc, char **argv)

+{

+  path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir);

+  if (mkdtemp (path_chroot) == NULL)

+    FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", path_chroot);

+  add_temp_file (path_chroot);

+

+  /* Create the /etc directory in the chroot environment.  */

+  char *path_etc = xasprintf ("%s/etc", path_chroot);

+  xmkdir (path_etc, 0777);

+  add_temp_file (path_etc);

+

+  /* Create an empty resolv.conf file.  */

+  path_resolv_conf = xasprintf ("%s/resolv.conf", path_etc);

+  add_temp_file (path_resolv_conf);

+  support_write_file_string (path_resolv_conf, "");

+

+  free (path_etc);

+

+  /* valgrind needs a temporary directory in the chroot.  */

+  {

+    char *path_tmp = xasprintf ("%s/tmp", path_chroot);

+    xmkdir (path_tmp, 0777);

+    add_temp_file (path_tmp);

+    free (path_tmp);

+  }

+}

+

+/* Verify that the chroot environment has been set up.  */

+static void

+check_chroot_working (void *closure)

+{

+  xchroot (path_chroot);

+  FILE *fp = xfopen (_PATH_RESCONF, "r");

+  xfclose (fp);

+

+  TEST_VERIFY_EXIT (res_init () == 0);

+  TEST_VERIFY (_res.options & RES_INIT);

+

+  char buf[100];

+  if (gethostname (buf, sizeof (buf)) < 0)

+    FAIL_EXIT1 ("gethostname: %m");

+  if (strcmp (buf, test_hostname) != 0)

+    FAIL_EXIT1 ("unexpected host name: %s", buf);

+}

+

+/* If FLAG is set in *OPTIONS, write NAME to FP, and clear it in

+   *OPTIONS.  */

+static void

+print_option_flag (FILE *fp, int *options, int flag, const char *name)

+{

+  if (*options & flag)

+    {

+      fprintf (fp, " %s", name);

+      *options &= ~flag;

+    }

+}

+

+/* Write a decoded version of the resolver configuration *RESP to the

+   stream FP.  */

+static void

+print_resp (FILE *fp, res_state resp)

+{

+  /* The options directive.  */

+  {

+    /* RES_INIT is used internally for tracking initialization.  */

+    TEST_VERIFY (resp->options & RES_INIT);

+    /* Also mask out other default flags which cannot be set through

+       the options directive.  */

+    int options

+      = resp->options & ~(RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH);

+    if (options != 0

+        || resp->ndots != 1

+        || resp->retrans != RES_TIMEOUT

+        || resp->retry != RES_DFLRETRY)

+      {

+        fputs ("options", fp);

+        if (resp->ndots != 1)

+          fprintf (fp, " ndots:%d", resp->ndots);

+        if (resp->retrans != RES_TIMEOUT)

+          fprintf (fp, " timeout:%d", resp->retrans);

+        if (resp->retry != RES_DFLRETRY)

+          fprintf (fp, " attempts:%d", resp->retry);

+        print_option_flag (fp, &options, RES_USEVC, "use-vc");

+        print_option_flag (fp, &options, DEPRECATED_RES_USE_INET6, "inet6");

+        print_option_flag (fp, &options, RES_ROTATE, "rotate");

+        print_option_flag (fp, &options, RES_USE_EDNS0, "edns0");

+        print_option_flag (fp, &options, RES_SNGLKUP,

+                           "single-request");

+        print_option_flag (fp, &options, RES_SNGLKUPREOP,

+                           "single-request-reopen");

+        print_option_flag (fp, &options, RES_NOTLDQUERY, "no-tld-query");

+        fputc ('\n', fp);

+        if (options != 0)

+          fprintf (fp, "; error: unresolved option bits: 0x%x\n", options);

+      }

+  }

+

+  /* The search and domain directives.  */

+  if (resp->dnsrch[0] != NULL)

+    {

+      fputs ("search", fp);

+      for (int i = 0; i < MAXDNSRCH && resp->dnsrch[i] != NULL; ++i)

+        {

+          fputc (' ', fp);

+          fputs (resp->dnsrch[i], fp);

+        }

+      fputc ('\n', fp);

+    }

+  else if (resp->defdname[0] != '\0')

+    fprintf (fp, "domain %s\n", resp->defdname);

+

+  /* The sortlist directive.  */

+  if (resp->nsort > 0)

+    {

+      fputs ("sortlist", fp);

+      for (int i = 0; i < resp->nsort && i < MAXRESOLVSORT; ++i)

+        {

+          char net[20];

+          if (inet_ntop (AF_INET, &resp->sort_list[i].addr,

+                         net, sizeof (net)) == NULL)

+            FAIL_EXIT1 ("inet_ntop: %m\n");

+          char mask[20];

+          if (inet_ntop (AF_INET, &resp->sort_list[i].mask,

+                         mask, sizeof (mask)) == NULL)

+            FAIL_EXIT1 ("inet_ntop: %m\n");

+          fprintf (fp, " %s/%s", net, mask);

+        }

+      fputc ('\n', fp);

+    }

+

+  /* The nameserver directives.  */

+  for (size_t i = 0; i < resp->nscount; ++i)

+    {

+      char host[NI_MAXHOST];

+      char service[NI_MAXSERV];

+

+      /* See get_nsaddr in res_send.c.  */

+      void *addr;

+      size_t addrlen;

+      if (resp->nsaddr_list[i].sin_family == 0

+          && resp->_u._ext.nsaddrs[i] != NULL)

+        {

+          addr = resp->_u._ext.nsaddrs[i];

+          addrlen = sizeof (*resp->_u._ext.nsaddrs[i]);

+        }

+      else

+        {

+          addr = &resp->nsaddr_list[i];

+          addrlen = sizeof (resp->nsaddr_list[i]);

+        }

+

+      int ret = getnameinfo (addr, addrlen,

+                             host, sizeof (host), service, sizeof (service),

+                             NI_NUMERICHOST | NI_NUMERICSERV);

+      if (ret != 0)

+        {

+          if (ret == EAI_SYSTEM)

+            fprintf (fp, "; error: getnameinfo: %m\n");

+          else

+            fprintf (fp, "; error: getnameinfo: %s\n", gai_strerror (ret));

+        }

+      else

+        {

+          fprintf (fp, "nameserver %s\n", host);

+          if (strcmp (service, "53") != 0)

+            fprintf (fp, "; unrepresentable port number %s\n\n", service);

+        }

+    }

+

+  TEST_VERIFY (!ferror (fp));

+}

+

+/* Parameters of one test case.  */

+struct test_case

+{

+  /* A short, descriptive name of the test.  */

+  const char *name;

+

+  /* The contents of the /etc/resolv.conf file.  */

+  const char *conf;

+

+  /* The expected output from print_resp.  */

+  const char *expected;

+

+  /* Setting for the LOCALDOMAIN environment variable.  NULL if the

+     variable is not to be set.  */

+  const char *localdomain;

+

+  /* Setting for the RES_OPTIONS environment variable.  NULL if the

+     variable is not to be set.  */

+  const char *res_options;

+};

+

+enum test_init

+{

+  test_init,

+  test_ninit,

+  test_mkquery,

+  test_gethostbyname,

+  test_getaddrinfo,

+  test_init_method_last = test_getaddrinfo

+};

+

+/* Closure argument for run_res_init.  */

+struct test_context

+{

+  enum test_init init;

+  const struct test_case *t;

+};

+

+static void

+setup_nss_dns_and_chroot (void)

+{

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

+  if (dlopen (LIBNSS_DNS_SO, RTLD_LAZY) == NULL)

+    FAIL_EXIT1 ("could not load " LIBNSS_DNS_SO ": %s", dlerror ());

+  xchroot (path_chroot);

+  /* Force the use of nss_dns.  */

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

+}

+

+/* Run res_ninit or res_init in a subprocess and dump the parsed

+   resolver state to standard output.  */

+static void

+run_res_init (void *closure)

+{

+  struct test_context *ctx = closure;

+  TEST_VERIFY (getenv ("LOCALDOMAIN") == NULL);

+  TEST_VERIFY (getenv ("RES_OPTIONS") == NULL);

+  if (ctx->t->localdomain != NULL)

+    setenv ("LOCALDOMAIN", ctx->t->localdomain, 1);

+  if (ctx->t->res_options != NULL)

+    setenv ("RES_OPTIONS", ctx->t->res_options, 1);

+

+  switch (ctx->init)

+    {

+    case test_init:

+      xchroot (path_chroot);

+      TEST_VERIFY (res_init () == 0);

+      print_resp (stdout, &_res);

+      return;

+

+    case test_ninit:

+      xchroot (path_chroot);

+      res_state resp = xmalloc (sizeof (*resp));

+      memset (resp, 0, sizeof (*resp));

+      TEST_VERIFY (res_ninit (resp) == 0);

+      print_resp (stdout, resp);

+      res_nclose (resp);

+      free (resp);

+      return;

+

+    case test_mkquery:

+      xchroot (path_chroot);

+      unsigned char buf[512];

+      TEST_VERIFY (res_mkquery (QUERY, "www.example",

+                                C_IN, ns_t_a, NULL, 0,

+                                NULL, buf, sizeof (buf)) > 0);

+      print_resp (stdout, &_res);

+      return;

+

+    case test_gethostbyname:

+      setup_nss_dns_and_chroot ();

+      /* Trigger implicit initialization of the _res structure.  The

+         actual lookup result is immaterial.  */

+      (void )gethostbyname ("www.example");

+      print_resp (stdout, &_res);

+      return;

+

+    case test_getaddrinfo:

+      setup_nss_dns_and_chroot ();

+      /* Trigger implicit initialization of the _res structure.  The

+         actual lookup result is immaterial.  */

+      struct addrinfo *ai;

+      (void) getaddrinfo ("www.example", NULL, NULL, &ai;;

+      print_resp (stdout, &_res);

+      return;

+    }

+

+  FAIL_EXIT1 ("invalid init method %d", ctx->init);

+}

+

+#if TEST_THREAD

+/* Helper function which calls run_res_init from a thread.  */

+static void *

+run_res_init_thread_func (void *closure)

+{

+  run_res_init (closure);

+  return NULL;

+}

+

+/* Variant of res_run_init which runs the function on a non-main

+   thread.  */

+static void

+run_res_init_on_thread (void *closure)

+{

+  xpthread_join (xpthread_create (NULL, run_res_init_thread_func, closure));

+}

+#endif /* TEST_THREAD */

+

+struct test_case test_cases[] =

+  {

+    {.name = "empty file",

+     .conf = "",

+     .expected = "search example.com\n"

+     "nameserver 127.0.0.1\n"

+    },

+    {.name = "empty file with LOCALDOMAIN",

+     .conf = "",

+     .expected = "search example.net\n"

+     "nameserver 127.0.0.1\n",

+     .localdomain = "example.net",

+    },

+    {.name = "empty file with RES_OPTIONS",

+     .conf = "",

+     .expected = "options attempts:5 edns0\n"

+     "search example.com\n"

+     "nameserver 127.0.0.1\n",

+     .res_options = "edns0 attempts:5",

+    },

+    {.name = "empty file with RES_OPTIONS and LOCALDOMAIN",

+     .conf = "",

+     .expected = "options attempts:5 edns0\n"

+     "search example.org\n"

+     "nameserver 127.0.0.1\n",

+     .localdomain = "example.org",

+     .res_options = "edns0 attempts:5",

+    },

+    {.name = "basic",

+     .conf = "domain example.net\n"

+     "search corp.example.com example.com\n"

+     "nameserver 192.0.2.1\n",

+     .expected = "search corp.example.com example.com\n"

+     "nameserver 192.0.2.1\n"

+    },

+    {.name = "whitespace",

+     .conf = "# This test covers comment and whitespace processing "

+     " (trailing whitespace,\n"

+     "# missing newline at end of file).\n"

+     "\n"

+     "domain  example.net\n"

+     ";search commented out\n"

+     "search corp.example.com\texample.com\n"

+     "#nameserver 192.0.2.3\n"

+     "nameserver 192.0.2.1 \n"

+     "nameserver 192.0.2.2",    /* No \n at end of file.  */

+     .expected = "search corp.example.com example.com\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 192.0.2.2\n"

+    },

+    {.name = "option values, multiple servers",

+     .conf = "options\tinet6\tndots:3 edns0\tattempts:5\ttimeout:19\n"

+     "domain  example.net\n"

+     ";domain comment\n"

+     "search corp.example.com\texample.com\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver ::1\n"

+     "nameserver 192.0.2.2\n",

+     .expected = "options ndots:3 timeout:19 attempts:5 inet6 edns0\n"

+     "search corp.example.com example.com\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver ::1\n"

+     "nameserver 192.0.2.2\n"

+    },

+    {.name = "out-of-range option vales",

+     .conf = "options use-vc timeout:999 attempts:999 ndots:99\n"

+     "search example.com\n",

+     .expected = "options ndots:15 timeout:30 attempts:5 use-vc\n"

+     "search example.com\n"

+     "nameserver 127.0.0.1\n"

+    },

+    {.name = "repeated directives",

+     .conf = "options ndots:3 use-vc\n"

+     "options edns0 ndots:2\n"

+     "domain corp.example\n"

+     "search example.net corp.example.com example.com\n"

+     "search example.org\n"

+     "search\n",

+     .expected = "options ndots:2 use-vc edns0\n"

+     "search example.org\n"

+     "nameserver 127.0.0.1\n"

+    },

+    {.name = "many name servers, sortlist",

+     .conf = "options single-request\n"

+     "search example.org example.com example.net corp.example.com\n"

+     "sortlist 192.0.2.0/255.255.255.0\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 192.0.2.2\n"

+     "nameserver 192.0.2.3\n"

+     "nameserver 192.0.2.4\n"

+     "nameserver 192.0.2.5\n"

+     "nameserver 192.0.2.6\n"

+     "nameserver 192.0.2.7\n"

+     "nameserver 192.0.2.8\n",

+     .expected = "options single-request\n"

+     "search example.org example.com example.net corp.example.com\n"

+     "sortlist 192.0.2.0/255.255.255.0\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 192.0.2.2\n"

+     "nameserver 192.0.2.3\n"

+    },

+    {.name = "IPv4 and IPv6 nameservers",

+     .conf = "options single-request\n"

+     "search example.org example.com example.net corp.example.com"

+     " legacy.example.com\n"

+     "sortlist 192.0.2.0\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 2001:db8::2\n"

+     "nameserver 192.0.2.3\n"

+     "nameserver 2001:db8::4\n"

+     "nameserver 192.0.2.5\n"

+     "nameserver 2001:db8::6\n"

+     "nameserver 192.0.2.7\n"

+     "nameserver 2001:db8::8\n",

+     .expected = "options single-request\n"

+     "search example.org example.com example.net corp.example.com"

+     " legacy.example.com\n"

+     "sortlist 192.0.2.0/255.255.255.0\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 2001:db8::2\n"

+     "nameserver 192.0.2.3\n"

+    },

+    {.name = "garbage after nameserver",

+     .conf = "nameserver 192.0.2.1 garbage\n"

+     "nameserver 192.0.2.2:5353\n"

+     "nameserver 192.0.2.3 5353\n",

+     .expected = "search example.com\n"

+     "nameserver 192.0.2.1\n"

+     "nameserver 192.0.2.3\n"

+    },

+    {.name = "RES_OPTIONS is cummulative",

+     .conf = "options timeout:7 ndots:2 use-vc\n"

+     "nameserver 192.0.2.1\n",

+     .expected = "options ndots:3 timeout:7 attempts:5 use-vc edns0\n"

+     "search example.com\n"

+     "nameserver 192.0.2.1\n",

+     .res_options = "attempts:5 ndots:3 edns0 ",

+    },

+    { NULL }

+  };

+

+/* Run the indicated test case.  This function assumes that the chroot

+   contents has already been set up.  */

+static void

+test_file_contents (const struct test_case *t)

+{

+#if TEST_THREAD

+  for (int do_thread = 0; do_thread < 2; ++do_thread)

+#endif

+    for (int init_method = 0; init_method <= test_init_method_last;

+         ++init_method)

+      {

+        if (test_verbose > 0)

+          printf ("info:  testing init method %d\n", init_method);

+        struct test_context ctx = { .init = init_method, .t = t };

+        void (*func) (void *) = run_res_init;

+#if TEST_THREAD

+        if (do_thread)

+          func = run_res_init_on_thread;

+#endif

+        struct support_capture_subprocess proc

+          = support_capture_subprocess (func, &ctx;;

+        if (strcmp (proc.out.buffer, t->expected) != 0)

+          {

+            support_record_failure ();

+            printf ("error: output mismatch for %s\n", t->name);

+            support_run_diff ("expected", t->expected,

+                              "actual", proc.out.buffer);

+          }

+        support_capture_subprocess_check (&proc, t->name, 0,

+                                          sc_allow_stdout);

+        support_capture_subprocess_free (&proc;;

+      }

+}

+

+static int

+do_test (void)

+{

+  support_become_root ();

+  support_enter_network_namespace ();

+  if (!support_in_uts_namespace () || !support_can_chroot ())

+    return EXIT_UNSUPPORTED;

+

+  /* We are in an UTS namespace, so we can set the host name without

+     altering the state of the entire system.  */

+  if (sethostname (test_hostname, strlen (test_hostname)) != 0)

+    FAIL_EXIT1 ("sethostname: %m");

+

+  /* These environment variables affect resolv.conf parsing.  */

+  unsetenv ("LOCALDOMAIN");

+  unsetenv ("RES_OPTIONS");

+

+  /* Ensure that the chroot setup worked.  */

+  {

+    struct support_capture_subprocess proc

+      = support_capture_subprocess (check_chroot_working, NULL);

+    support_capture_subprocess_check (&proc, "chroot", 0, sc_allow_none);

+    support_capture_subprocess_free (&proc;;

+  }

+

+  for (size_t i = 0; test_cases[i].name != NULL; ++i)

+    {

+      if (test_verbose > 0)

+        printf ("info: running test: %s\n", test_cases[i].name);

+      TEST_VERIFY (test_cases[i].conf != NULL);

+      TEST_VERIFY (test_cases[i].expected != NULL);

+

+      support_write_file_string (path_resolv_conf, test_cases[i].conf);

+

+      test_file_contents (&test_cases[i]);

+

+      /* The expected output from the empty file test is used for

+         further tests.  */

+      if (test_cases[i].conf[0] == '\0')

+        {

+          if (test_verbose > 0)

+            printf ("info:  special test: missing file\n");

+          TEST_VERIFY (unlink (path_resolv_conf) == 0);

+          test_file_contents (&test_cases[i]);

+

+          if (test_verbose > 0)

+            printf ("info:  special test: dangling symbolic link\n");

+          TEST_VERIFY (symlink ("does-not-exist", path_resolv_conf) == 0);

+          test_file_contents (&test_cases[i]);

+          TEST_VERIFY (unlink (path_resolv_conf) == 0);

+

+          if (test_verbose > 0)

+            printf ("info:  special test: unreadable file\n");

+          support_write_file_string (path_resolv_conf, "");

+          TEST_VERIFY (chmod (path_resolv_conf, 0) == 0);

+          test_file_contents (&test_cases[i]);

+

+          /* Restore the empty file.  */

+          TEST_VERIFY (unlink (path_resolv_conf) == 0);

+          support_write_file_string (path_resolv_conf, "");

+        }

+    }

+

+  free (path_chroot);

+  path_chroot = NULL;

+  free (path_resolv_conf);

+  path_resolv_conf = NULL;

+  return 0;

+}

+

+#define PREPARE prepare

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

diff --git a/resolv/tst-resolv-res_init-thread.c b/resolv/tst-resolv-res_init-thread.c

new file mode 100644

index 0000000000000000..f47ac34f7fc7a6c8

--- /dev/null

+++ b/resolv/tst-resolv-res_init-thread.c

@@ -0,0 +1,20 @@

+/* Test parsing of /etc/resolv.conf, threading version.

+   Copyright (C) 2017 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/>.  */

+

+#define TEST_THREAD 1

+#include "tst-resolv-res_init-skeleton.c"

diff --git a/resolv/tst-resolv-res_init.c b/resolv/tst-resolv-res_init.c

new file mode 100644

index 0000000000000000..40c0154eca7363cb

--- /dev/null

+++ b/resolv/tst-resolv-res_init.c

@@ -0,0 +1,20 @@

+/* Test parsing of /etc/resolv.conf, non-threading version.

+   Copyright (C) 2017 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/>.  */

+

+#define TEST_THREAD 0

+#include "tst-resolv-res_init-skeleton.c"