Implement the mlock2 function

Fallback using mlock is provided if the flags argument is zero.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-mlock2.c b/sysdeps/unix/sysv/linux/tst-mlock2.c
new file mode 100644
index 0000000000..53c435a12a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-mlock2.c
@@ -0,0 +1,66 @@
+/* Test the mlock2 function.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   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/xunistd.h>
+#include <sys/mman.h>
+
+/* Allocate a page using mmap.  */
+static void *
+get_page (void)
+{
+  return xmmap (NULL, 1, PROT_READ | PROT_WRITE,
+                MAP_ANONYMOUS | MAP_PRIVATE, -1);
+}
+
+static int
+do_test (void)
+{
+  /* Current kernels have a small reserve of locked memory, so this
+     test does not need any privileges to run.  */
+
+  void *page = get_page ();
+  if (mlock (page, 1) != 0)
+    FAIL_EXIT1 ("mlock: %m\n");
+  xmunmap (page, 1);
+
+  page = get_page ();
+  if (mlock2 (page, 1, 0) != 0)
+    /* Should be implemented using mlock if necessary.  */
+    FAIL_EXIT1 ("mlock2 (0): %m\n");
+  xmunmap (page, 1);
+
+  page = get_page ();
+  int ret = mlock2 (page, 1, MLOCK_ONFAULT);
+  if (ret != 0)
+    {
+      TEST_VERIFY (ret == -1);
+      if (errno != EINVAL)
+        /* EINVAL means the system does not support the mlock2 system
+           call.  */
+        FAIL_EXIT1 ("mlock2 (0): %m\n");
+      else
+        puts ("warning: mlock2 system call not supported");
+    }
+  xmunmap (page, 1);
+
+  return 0;
+}
+
+#include <support/test-driver.c>