1 files changed, 66 insertions, 0 deletions
diff --git a/src/grep/gnulib-tests/altstack-util.h b/src/grep/gnulib-tests/altstack-util.h
new file mode 100644
index 0000000..fbd0d13
--- /dev/null
+++ b/src/grep/gnulib-tests/altstack-util.h
@@ -0,0 +1,66 @@
+/* Some auxiliary stuff for defining an alternate stack.
+   Copyright (C) 2010-2021 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Eric Blake and Bruno Haible.  */
+
+#include <stdint.h> /* uintptr_t */
+#include <string.h> /* for memset */
+
+#define MYSTACK_SIZE (1 << 24)
+
+/* glibc says: Users should use SIGSTKSZ as the size of user-supplied
+   buffers.  We want to detect stack overflow of the alternate stack
+   in a nicer manner than just crashing, so we overallocate in
+   comparison to what we hand libsigsegv.  Also, we intentionally hand
+   an unaligned pointer, to ensure the alternate stack still ends up
+   aligned.  */
+#define MYSTACK_CRUMPLE_ZONE 8192
+static char mystack_storage[MYSTACK_SIZE + 2 * MYSTACK_CRUMPLE_ZONE + 31];
+static char *mystack; /* MYSTACK_SIZE bytes in the middle of storage. */
+
+static void
+prepare_alternate_stack (void)
+{
+#ifdef SIGSTKSZ
+  if (MYSTACK_SIZE < SIGSTKSZ)
+    {
+      size_t size = SIGSTKSZ;
+      printf ("SIGSTKSZ=%zu exceeds MYSTACK_SIZE=%d\n", size, MYSTACK_SIZE);
+      exit (1);
+    }
+#endif
+  memset (mystack_storage, 's', sizeof mystack_storage);
+  mystack = (char *) ((uintptr_t) (mystack_storage + MYSTACK_CRUMPLE_ZONE) | 31);
+}
+
+static void
+check_alternate_stack_no_overflow (void)
+{
+  unsigned int i;
+
+  for (i = MYSTACK_CRUMPLE_ZONE; i > 0; i--)
+    if (*(mystack - i) != 's')
+      {
+        printf ("Alternate stack was exceeded by %u bytes!!\n", i);
+        exit (1);
+      }
+  for (i = MYSTACK_CRUMPLE_ZONE; i > 0; i--)
+    if (*(mystack + MYSTACK_SIZE - 1 + i) != 's')
+      {
+        printf ("Alternate stack was exceeded by %u bytes!!\n", i);
+        exit (1);
+      }
+}