/*

Copyright 1988, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its

documentation for any purpose is hereby granted without fee, provided that

the above copyright notice appear in all copies and that both that

copyright notice and this permission notice appear in supporting

documentation.

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE

OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN

AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be

used in advertising or otherwise to promote the sale, use or other dealings

in this Software without prior written authorization from The Open Group.

*/

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <X11/Xauth.h>

#include <X11/Xos.h>

#include <assert.h>

#include <stdlib.h>

static char *buf = NULL;

static void

free_filename_buffer(void)

{

    free(buf);

    buf = NULL;

}

char *

XauFileName (void)

{

    const char *slashDotXauthority = "/.Xauthority";

    char    *name;

    static size_t	bsize;

    static int atexit_registered = 0;

#ifdef WIN32

    char    dir[128];

#endif

    size_t  size;

    if ((name = getenv ("XAUTHORITY")))

	return name;

    name = getenv ("HOME");

    if (!name) {

#ifdef WIN32

	if ((name = getenv("USERNAME"))) {

	    snprintf(dir, sizeof(dir), "/users/%s", name);

	    name = dir;

	}

	if (!name)

#endif

	return NULL;

    }

    size = strlen (name) + strlen(&slashDotXauthority[1]) + 2;

    if ((size > bsize) || (buf == NULL)) {

	free (buf);

        assert(size > 0);

	buf = malloc (size);

	if (!buf) {

	    bsize = 0;

	    return NULL;

	}

        if (!atexit_registered) {

            atexit(free_filename_buffer);

            atexit_registered = 1;

        }

	bsize = size;

    }

    snprintf (buf, bsize, "%s%s", name,

              slashDotXauthority + (name[0] == '/' && name[1] == '\0' ? 1 : 0));

    return buf;

}