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, 88 insertions, 0 deletions

diff --git a/libgnu/fstat.c b/libgnu/fstat.c
new file mode 100644
index 00000000..a5aabc56
--- /dev/null
+++ b/libgnu/fstat.c
@@ -0,0 +1,88 @@
+/* fstat() replacement.
+   Copyright (C) 2011-2017 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/>.  */
+
+/* If the user's config.h happens to include <sys/stat.h>, let it include only
+   the system's <sys/stat.h> here, so that orig_fstat doesn't recurse to
+   rpl_fstat.  */
+#define __need_system_sys_stat_h
+#include <config.h>
+
+/* Get the original definition of fstat.  It might be defined as a macro.  */
+#include <sys/types.h>
+#include <sys/stat.h>
+#if _GL_WINDOWS_64_BIT_ST_SIZE
+# undef stat /* avoid warning on mingw64 with _FILE_OFFSET_BITS=64 */
+# define stat _stati64
+# undef fstat /* avoid warning on mingw64 with _FILE_OFFSET_BITS=64 */
+# define fstat _fstati64
+#endif
+#undef __need_system_sys_stat_h
+
+static int
+orig_fstat (int fd, struct stat *buf)
+{
+  return fstat (fd, buf);
+}
+
+/* Specification.  */
+/* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
+   eliminates this include because of the preliminary #include <sys/stat.h>
+   above.  */
+#include "sys/stat.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# include "msvc-inval.h"
+#endif
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+static int
+fstat_nothrow (int fd, struct stat *buf)
+{
+  int result;
+
+  TRY_MSVC_INVAL
+    {
+      result = orig_fstat (fd, buf);
+    }
+  CATCH_MSVC_INVAL
+    {
+      result = -1;
+      errno = EBADF;
+    }
+  DONE_MSVC_INVAL;
+
+  return result;
+}
+#else
+# define fstat_nothrow orig_fstat
+#endif
+
+int
+rpl_fstat (int fd, struct stat *buf)
+{
+#if REPLACE_FCHDIR && REPLACE_OPEN_DIRECTORY
+  /* Handle the case when rpl_open() used a dummy file descriptor to work
+     around an open() that can't normally visit directories.  */
+  const char *name = _gl_directory_name (fd);
+  if (name != NULL)
+    return stat (name, buf);
+#endif
+
+  return fstat_nothrow (fd, buf);
+}