new module 'getlogin'

[Bruno Haible]

John W. Eaton wrote:
> getlogin doesn't exist on Windows systems.
> 
> What would be the preferred way of fixing this problem?  Should there
> be a separate getlogin module?

Even though getlogin_r does not require a 'getlogin' module, it is indeed
fairly easy to add:


2010-01-09  Bruno Haible  <address@hidden>

        New module 'getlogin'.
        * lib/unistd.in.h (getlogin): New declaration.
        * lib/getlogin.c: New file.
        * m4/getlogin.m4: New file.
        * m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Initialize GNULIB_GETLOGIN,
        HAVE_GETLOGIN.
        * modules/unistd (Makefile.am): Substitute GNULIB_GETLOGIN,
        HAVE_GETLOGIN.
        * modules/getlogin: New file.
        * doc/posix-functions/getlogin.texi: Mention the new module.
        Reported by John W. Eaton <address@hidden>.

=============================== lib/getlogin.c ===============================
/* Provide a working getlogin for systems which lack it.

   Copyright (C) 2010 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 Bruno Haible, 2010.  */

#include <config.h>

/* Specification.  */
#include <unistd.h>

#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif

char *
getlogin (void)
{
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  static char login_name[1024];
  DWORD sz = sizeof (login_name);

  if (GetUserName (login_name, &sz))
    return login_name;
#endif
  return NULL;
}
=============================== m4/getlogin.m4 ===============================
# getlogin.m4 serial 1
dnl Copyright (C) 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_GETLOGIN],
[
  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  AC_CHECK_FUNCS_ONCE([getlogin])
  if test $ac_cv_func_getlogin = no; then
    AC_LIBOBJ([getlogin])
    HAVE_GETLOGIN=0
  fi
])
============================== modules/getlogin ==============================
Description:
getlogin() function: Get user name.

Files:
lib/getlogin.c
m4/getlogin.m4

Depends-on:
unistd

configure.ac:
gl_GETLOGIN
gl_UNISTD_MODULE_INDICATOR([getlogin])

Makefile.am:

Include:
<unistd.h>

License:
LGPLv2+

Maintainer:
all
===============================================================================
--- doc/posix-functions/getlogin.texi.orig      Sat Jan  9 16:12:51 2010
+++ doc/posix-functions/getlogin.texi   Sat Jan  9 15:15:18 2010
@@ -4,15 +4,15 @@
 
 POSIX specification: 
@url{http://www.opengroup.org/onlinepubs/9699919799/functions/getlogin.html}
 
-Gnulib module: ---
+Gnulib module: getlogin
 
 Portability problems fixed by Gnulib:
 @itemize
address@hidden
+This function is missing on some platforms:
+mingw.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
address@hidden
-This function is missing on some platforms:
-mingw.
 @end itemize
--- lib/unistd.in.h.orig        Sat Jan  9 16:12:51 2010
+++ lib/unistd.in.h     Sat Jan  9 15:15:18 2010
@@ -476,6 +476,29 @@
 #endif
 
 
+#if @GNULIB_GETLOGIN@
+/* Returns the user's login name, or NULL if it cannot be found.  Upon error,
+   returns NULL with errno set.
+
+   See <http://www.opengroup.org/susv3xsh/getlogin.html>.
+
+   Most programs don't need to use this function, because the information is
+   available through environment variables:
+     ${LOGNAME-$USER}        on Unix platforms,
+     $USERNAME               on native Windows platforms.
+ */
+# if address@hidden@
+extern char *getlogin (void);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef getlogin
+# define getlogin() \
+    (GL_LINK_WARNING ("getlogin is unportable - " \
+                      "use gnulib module getlogin for portability"), \
+     getlogin ())
+#endif
+
+
 #if @GNULIB_GETLOGIN_R@
 /* Copies the user's login name to NAME.
    The array pointed to by NAME has room for SIZE bytes.
--- m4/unistd_h.m4.orig Sat Jan  9 16:12:51 2010
+++ m4/unistd_h.m4      Sat Jan  9 15:15:18 2010
@@ -1,4 +1,4 @@
-# unistd_h.m4 serial 36
+# unistd_h.m4 serial 37
 dnl Copyright (C) 2006-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -48,6 +48,7 @@
   GNULIB_GETDTABLESIZE=0;    AC_SUBST([GNULIB_GETDTABLESIZE])
   GNULIB_GETGROUPS=0;        AC_SUBST([GNULIB_GETGROUPS])
   GNULIB_GETHOSTNAME=0;      AC_SUBST([GNULIB_GETHOSTNAME])
+  GNULIB_GETLOGIN=0;         AC_SUBST([GNULIB_GETLOGIN])
   GNULIB_GETLOGIN_R=0;       AC_SUBST([GNULIB_GETLOGIN_R])
   GNULIB_GETPAGESIZE=0;      AC_SUBST([GNULIB_GETPAGESIZE])
   GNULIB_GETUSERSHELL=0;     AC_SUBST([GNULIB_GETUSERSHELL])
@@ -82,6 +83,7 @@
   HAVE_GETDTABLESIZE=1;   AC_SUBST([HAVE_GETDTABLESIZE])
   HAVE_GETGROUPS=1;       AC_SUBST([HAVE_GETGROUPS])
   HAVE_GETHOSTNAME=1;     AC_SUBST([HAVE_GETHOSTNAME])
+  HAVE_GETLOGIN=1;        AC_SUBST([HAVE_GETLOGIN])
   HAVE_GETPAGESIZE=1;     AC_SUBST([HAVE_GETPAGESIZE])
   HAVE_GETUSERSHELL=1;    AC_SUBST([HAVE_GETUSERSHELL])
   HAVE_LCHOWN=1;          AC_SUBST([HAVE_LCHOWN])
--- modules/unistd.orig Sat Jan  9 16:12:51 2010
+++ modules/unistd      Sat Jan  9 15:15:18 2010
@@ -42,6 +42,7 @@
              -e 's|@''GNULIB_GETDTABLESIZE''@|$(GNULIB_GETDTABLESIZE)|g' \
              -e 's|@''GNULIB_GETGROUPS''@|$(GNULIB_GETGROUPS)|g' \
              -e 's|@''GNULIB_GETHOSTNAME''@|$(GNULIB_GETHOSTNAME)|g' \
+             -e 's|@''GNULIB_GETLOGIN''@|$(GNULIB_GETLOGIN)|g' \
              -e 's|@''GNULIB_GETLOGIN_R''@|$(GNULIB_GETLOGIN_R)|g' \
              -e 's|@''GNULIB_GETPAGESIZE''@|$(GNULIB_GETPAGESIZE)|g' \
              -e 's|@''GNULIB_GETUSERSHELL''@|$(GNULIB_GETUSERSHELL)|g' \
@@ -75,6 +76,7 @@
              -e 's|@''HAVE_GETDTABLESIZE''@|$(HAVE_GETDTABLESIZE)|g' \
              -e 's|@''HAVE_GETGROUPS''@|$(HAVE_GETGROUPS)|g' \
              -e 's|@''HAVE_GETHOSTNAME''@|$(HAVE_GETHOSTNAME)|g' \
+             -e 's|@''HAVE_GETLOGIN''@|$(HAVE_GETLOGIN)|g' \
              -e 's|@''HAVE_GETPAGESIZE''@|$(HAVE_GETPAGESIZE)|g' \
              -e 's|@''HAVE_GETUSERSHELL''@|$(HAVE_GETUSERSHELL)|g' \
              -e 's|@''HAVE_LCHOWN''@|$(HAVE_LCHOWN)|g' \