support: Add support_set_vma_name

Check if kernel supports prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, ...).
Reviewed-by: DJ Delorie <dj@redhat.com>

3 files changed, 54 insertions, 0 deletions

diff --git a/support/Makefile b/support/Makefile
index 917a858..9aa7f23 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -80,6 +80,7 @@ libsupport-routines = \
   support_select_modifies_timeout \
   support_select_normalizes_timeout \
   support_set_small_thread_stack_size \
+  support_set_vma_name_supported \
   support_shared_allocate \
   support_small_stack_thread_attribute \
   support_socket_so_timestamp_time64 \
diff --git a/support/support.h b/support/support.h
index b7f76bf..4a068d3 100644
--- a/support/support.h
+++ b/support/support.h
@@ -235,6 +235,10 @@ void support_stack_free (struct support_stack *stack);
    The returned value is the lowest file descriptor number.  */
 int support_open_dev_null_range (int num, int flags, mode_t mode);
 
+
+/* Check if kernel supports set VMA range name.  */
+extern bool support_set_vma_name_supported (void);
+
 __END_DECLS
 
 #endif /* SUPPORT_H */
diff --git a/support/support_set_vma_name_supported.c b/support/support_set_vma_name_supported.c
new file mode 100644
index 0000000..712caa9
--- /dev/null
+++ b/support/support_set_vma_name_supported.c
@@ -0,0 +1,49 @@
+/* Check if kernel supports set VMA range name.
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+#ifdef __linux__
+# include <sys/prctl.h>
+#endif
+
+bool
+support_set_vma_name_supported (void)
+{
+#ifdef __linux__
+  size_t size = sysconf (_SC_PAGESIZE);
+  if (size == -1)
+    FAIL_EXIT1 ("sysconf (_SC_PAGESIZE): %m\n");
+
+  void *vma = xmmap (0,
+		     size,
+		     PROT_NONE,
+		     MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
+		     -1);
+
+  int r = prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, vma, size, "vmaname");
+
+  xmunmap (vma, size);
+
+  return r == 0;
+#else
+  return false;
+#endif
+}