resolv: Tests for various versions of res_init

1 files changed, 65 insertions, 0 deletions

diff --git a/support/support_can_chroot.c b/support/support_can_chroot.c
new file mode 100644
index 0000000000..0dfd2deb54
--- /dev/null
+++ b/support/support_can_chroot.c
@@ -0,0 +1,65 @@
+/* Return true if the process can perform a chroot operation.
+   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 <errno.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/support.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <xunistd.h>
+
+static void
+callback (void *closure)
+{
+  int *result = closure;
+  struct stat64 before;
+  xstat ("/dev", &before);
+  if (chroot ("/dev") != 0)
+    {
+      *result = errno;
+      return;
+    }
+  struct stat64 after;
+  xstat ("/", &after);
+  TEST_VERIFY (before.st_dev == after.st_dev);
+  TEST_VERIFY (before.st_ino == after.st_ino);
+  *result = 0;
+}
+
+bool
+support_can_chroot (void)
+{
+  int *result = support_shared_allocate (sizeof (*result));
+  *result = 0;
+  support_isolate_in_subprocess (callback, result);
+  bool ok = *result == 0;
+  if (!ok)
+    {
+      static bool already_warned;
+      if (!already_warned)
+        {
+          already_warned = true;
+          errno = *result;
+          printf ("warning: this process does not support chroot: %m\n");
+        }
+    }
+  support_shared_free (result);
+  return ok;
+}