resolv: Introduce free list for resolv_conf index slosts

1 files changed, 74 insertions, 0 deletions

diff --git a/resolv/tst-resolv-res_ninit.c b/resolv/tst-resolv-res_ninit.c
new file mode 100644
index 0000000000..d08153fed7
--- /dev/null
+++ b/resolv/tst-resolv-res_ninit.c
@@ -0,0 +1,74 @@
+/* Test the creation of many struct __res_state objects.
+   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 <mcheck.h>
+#include <resolv.h>
+#include <resolv/resolv_context.h>
+#include <stdlib.h>
+#include <support/check.h>
+
+/* Order the resolver states by their extended resolver state
+   index.  */
+static int
+sort_res_state (const void *a, const void *b)
+{
+  res_state left = (res_state) a;
+  res_state right = (res_state) b;
+  return memcmp (&left->_u._ext.__glibc_extension_index,
+                 &right->_u._ext.__glibc_extension_index,
+                 sizeof (left->_u._ext.__glibc_extension_index));
+}
+
+static int
+do_test (void)
+{
+  mtrace ();
+
+  enum { count = 100 * 1000 };
+  res_state array = calloc (count, sizeof (*array));
+  const struct resolv_conf *conf = NULL;
+  for (size_t i = 0; i < count; ++i)
+    {
+      TEST_VERIFY (res_ninit (array + i) == 0);
+      TEST_VERIFY (array[i].nscount > 0);
+      struct resolv_context *ctx = __resolv_context_get_override (array + i);
+      TEST_VERIFY_EXIT (ctx != NULL);
+      TEST_VERIFY (ctx->resp == array + i);
+      if (i == 0)
+        {
+          conf = ctx->conf;
+          TEST_VERIFY (conf != NULL);
+        }
+      else
+        /* The underyling configuration should be identical across all
+           res_state opjects because resolv.conf did not change.  */
+        TEST_VERIFY (ctx->conf == conf);
+    }
+  qsort (array, count, sizeof (*array), sort_res_state);
+  for (size_t i = 1; i < count; ++i)
+    /* All extension indices should be different.  */
+    TEST_VERIFY (sort_res_state (array + i - 1, array + i) < 0);
+  for (size_t i = 0; i < count; ++i)
+    res_nclose (array + i);
+  free (array);
+
+  TEST_VERIFY (res_init () == 0);
+  return 0;
+}
+
+#include <support/test-driver.c>