1 files changed, 57 insertions, 0 deletions
diff --git a/elf/tst-link-map-contiguous-libc.c b/elf/tst-link-map-contiguous-libc.c
new file mode 100644
index 0000000..eb5728c
--- /dev/null
+++ b/elf/tst-link-map-contiguous-libc.c
@@ -0,0 +1,57 @@
+/* Check that the entire libc.so program image is readable if contiguous.
+   Copyright (C) 2025 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 <gnu/lib-names.h>
+#include <link.h>
+#include <support/check.h>
+#include <support/xdlfcn.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+static int
+do_test (void)
+{
+  struct link_map *l = xdlopen (LIBC_SO, RTLD_NOW);
+
+  /* The dynamic loader fills holes with PROT_NONE mappings.  */
+  if (!l->l_contiguous)
+    FAIL_EXIT1 ("libc.so link map is not contiguous");
+
+  /* Direct probing does not work because not everything is readable
+     due to PROT_NONE mappings.  */
+  int pagesize = getpagesize ();
+  ElfW(Addr) addr = l->l_map_start;
+  TEST_COMPARE (addr % pagesize, 0);
+  while (addr < l->l_map_end)
+    {
+      void *expected = (void *) addr;
+      void *ptr = xmmap (expected, 1, PROT_READ | PROT_WRITE,
+                         MAP_PRIVATE | MAP_ANONYMOUS, -1);
+      if (ptr == expected)
+        FAIL ("hole in libc.so memory image after %lu bytes",
+              (unsigned long int) (addr - l->l_map_start));
+      xmunmap (ptr, 1);
+      addr += pagesize;
+    }
+
+  xdlclose (l);
+
+  return 0;
+}
+#include <support/test-driver.c>