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, 85 insertions, 0 deletions

diff --git a/libgnu/read.c b/libgnu/read.c
new file mode 100644
index 00000000..08108f7f
--- /dev/null
+++ b/libgnu/read.c
@@ -0,0 +1,85 @@
+/* POSIX compatible read() function.
+   Copyright (C) 2008-2017 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email protected]>, 2011.
+
+   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/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
+# include <errno.h>
+# include <io.h>
+
+# define WIN32_LEAN_AND_MEAN  /* avoid including junk */
+# include <windows.h>
+
+# include "msvc-inval.h"
+# include "msvc-nothrow.h"
+
+# undef read
+
+# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+static ssize_t
+read_nothrow (int fd, void *buf, size_t count)
+{
+  ssize_t result;
+
+  TRY_MSVC_INVAL
+    {
+      result = read (fd, buf, count);
+    }
+  CATCH_MSVC_INVAL
+    {
+      result = -1;
+      errno = EBADF;
+    }
+  DONE_MSVC_INVAL;
+
+  return result;
+}
+# else
+#  define read_nothrow read
+# endif
+
+ssize_t
+rpl_read (int fd, void *buf, size_t count)
+{
+  ssize_t ret = read_nothrow (fd, buf, count);
+
+# if GNULIB_NONBLOCKING
+  if (ret < 0
+      && GetLastError () == ERROR_NO_DATA)
+    {
+      HANDLE h = (HANDLE) _get_osfhandle (fd);
+      if (GetFileType (h) == FILE_TYPE_PIPE)
+        {
+          /* h is a pipe or socket.  */
+          DWORD state;
+          if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0)
+              && (state & PIPE_NOWAIT) != 0)
+            /* h is a pipe in non-blocking mode.
+               Change errno from EINVAL to EAGAIN.  */
+            errno = EAGAIN;
+        }
+    }
+# endif
+
+  return ret;
+}
+
+#endif