1 files changed, 110 insertions, 0 deletions
diff --git a/gl/lib/getlogin_r.c b/gl/lib/getlogin_r.c
new file mode 100644
index 0000000..a461112
--- /dev/null
+++ b/gl/lib/getlogin_r.c
@@ -0,0 +1,110 @@
+/* Provide a working getlogin_r for systems which lack it.
+
+   Copyright (C) 2005-2007, 2010-2020 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, 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 Paul Eggert, Derek Price, and Bruno Haible.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+#include <string.h>
+
+#include "malloca.h"
+
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+/* Don't assume that UNICODE is not defined.  */
+# undef GetUserName
+# define GetUserName GetUserNameA
+#else
+# if !HAVE_DECL_GETLOGIN
+extern char *getlogin (void);
+# endif
+#endif
+
+/* See unistd.in.h for documentation.  */
+int
+getlogin_r (char *name, size_t size)
+{
+#undef getlogin_r
+#if defined _WIN32 && ! defined __CYGWIN__
+  /* Native Windows platform.  */
+  DWORD sz;
+
+  /* When size > 0x7fff, the doc says that GetUserName will fail.
+     Actually, on Windows XP SP3, it succeeds.  But let's be safe,
+     for the sake of older Windows versions.  */
+  if (size > 0x7fff)
+    size = 0x7fff;
+  sz = size;
+  if (!GetUserName (name, &sz))
+    {
+      if (GetLastError () == ERROR_INSUFFICIENT_BUFFER)
+        /* In this case, the doc says that sz contains the required size, but
+           actually, on Windows XP SP3, it contains 2 * the required size.  */
+        return ERANGE;
+      else
+        return ENOENT;
+    }
+  return 0;
+#elif HAVE_GETLOGIN_R
+  /* Platform with a getlogin_r() function.  */
+  int ret = getlogin_r (name, size);
+
+  if (ret == 0)
+    {
+      const char *nul = memchr (name, '\0', size);
+      if (nul == NULL)
+        /* name contains a truncated result.  */
+        return ERANGE;
+      if (size > 0 && nul == name + size - 1)
+        {
+          /* strlen(name) == size-1.  Determine whether the untruncated result
+             would have had length size-1 or size.  */
+          char *room = (char *) malloca (size + 1);
+          if (room == NULL)
+            return ENOMEM;
+          ret = getlogin_r (room, size + 1);
+          /* The untruncated result should be the same as in the first call.  */
+          if (ret == 0 && memcmp (name, room, size) != 0)
+            /* The untruncated result would have been different.  */
+            ret = ERANGE;
+          freea (room);
+        }
+    }
+  return ret;
+#else
+  /* Platform with a getlogin() function.  */
+  char *n;
+  size_t nlen;
+
+  errno = 0;
+  n = getlogin ();
+  if (!n)
+    /* ENOENT is a reasonable errno value if getlogin returns NULL.  */
+    return (errno != 0 ? errno : ENOENT);
+
+  nlen = strlen (n);
+  if (size <= nlen)
+    return ERANGE;
+  memcpy (name, n, nlen + 1);
+  return 0;
+#endif
+}