resolv: Fix improper assert in __resolv_conf_attach

1 files changed, 89 insertions, 0 deletions

diff --git a/resolv/tst-resolv-res_init-multi.c b/resolv/tst-resolv-res_init-multi.c
new file mode 100644
index 0000000000..bdc68a5a33
--- /dev/null
+++ b/resolv/tst-resolv-res_init-multi.c
@@ -0,0 +1,89 @@
+/* Multi-threaded test for resolver initialization.
+   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/>.  */
+
+#include <netdb.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xthread.h>
+
+/* Whether name lookups succeed does not really matter.  We use this
+   to trigger initialization of the resolver.  */
+static const char *test_hostname = "www.gnu.org";
+
+/* The different initialization methods.  */
+enum test_type { init, byname, gai };
+enum { type_count = 3 };
+
+/* Thread function.  Perform a few resolver options.  */
+static void *
+thread_func (void *closure)
+{
+  enum test_type *ptype = closure;
+  /* Perform a few calls to the requested operation.  */
+  TEST_VERIFY (*ptype >= 0);
+  TEST_VERIFY (*ptype < (int) type_count);
+  for (int i = 0; i < 3; ++i)
+    switch (*ptype)
+      {
+      case init:
+	res_init ();
+	break;
+      case byname:
+	gethostbyname (test_hostname);
+	break;
+      case gai:
+	{
+	  struct addrinfo hints = { 0, };
+	  struct addrinfo *ai = NULL;
+	  if (getaddrinfo (test_hostname, "80", &hints, &ai) == 0)
+	    freeaddrinfo (ai);
+	}
+	break;
+      }
+  free (ptype);
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  /* Start a small number of threads which perform resolver
+     operations.  */
+  enum { thread_count = 30 };
+
+  pthread_t threads[thread_count];
+  for (int i = 0; i < thread_count; ++i)
+    {
+      enum test_type *ptype = xmalloc (sizeof (*ptype));
+      *ptype = i % type_count;
+      threads[i] = xpthread_create (NULL, thread_func, ptype);
+    }
+  for (int i = 0; i < type_count; ++i)
+    {
+      enum test_type *ptype = xmalloc (sizeof (*ptype));
+      *ptype = i;
+      thread_func (ptype);
+    }
+  for (int i = 0; i < thread_count; ++i)
+    xpthread_join (threads[i]);
+  return 0;
+}
+
+#include <support/test-driver.c>