Add gnulib modules to replace missing libc functionality

This enables us to build a fully featured elfutils package on systems
with reduced C libraries, such as windows. All the modules are built
into libgnu.a, which is then linked into all binaries if
--enable-gnulib is given on the configure line.

Change-Id: I743fd22172bc85d9f10dcc3dad8eb921f462b554
Reviewed-by: Christian Kandeler <[email protected]>

1 files changed, 52 insertions, 0 deletions

diff --git a/libgnu/cycle-check.h b/libgnu/cycle-check.h
new file mode 100644
index 00000000..0c9a68b6
--- /dev/null
+++ b/libgnu/cycle-check.h
@@ -0,0 +1,52 @@
+/* help detect directory cycles efficiently
+
+   Copyright (C) 2003-2004, 2006, 2009-2017 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 3 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 <http://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering */
+
+#ifndef CYCLE_CHECK_H
+# define CYCLE_CHECK_H 1
+
+# include <stdint.h>
+# include <stdbool.h>
+# include "dev-ino.h"
+# include "same-inode.h"
+
+struct cycle_check_state
+{
+  struct dev_ino dev_ino;
+  uintmax_t chdir_counter;
+  int magic;
+};
+
+void cycle_check_init (struct cycle_check_state *state);
+bool cycle_check (struct cycle_check_state *state, struct stat const *sb);
+
+# define CYCLE_CHECK_REFLECT_CHDIR_UP(State, SB_dir, SB_subdir) \
+  do                                                            \
+    {                                                           \
+      /* You must call cycle_check at least once before using this macro.  */ \
+      if ((State)->chdir_counter == 0)                          \
+        abort ();                                               \
+      if (SAME_INODE ((State)->dev_ino, SB_subdir))             \
+        {                                                       \
+          (State)->dev_ino.st_dev = (SB_dir).st_dev;            \
+          (State)->dev_ino.st_ino = (SB_dir).st_ino;            \
+        }                                                       \
+    }                                                           \
+  while (0)
+
+#endif