/* $Id$
 * UDP Gateway persistent configuration pathname detection
 * Copyright (C) 2005 Jan Kratochvil <project-udpgate@jankratochvil.net>
 * 
 * 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; exactly version 2 of June 1991 is required
 * 
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "config.h"

#include <glib/gmessages.h>
#include <glib/gmem.h>
#include <glib/gstrfuncs.h>
#include <glib/gutils.h>
#include <unistd.h>
#include <errno.h>
#include <stdarg.h>

#include "pathname.h"	/* self */


/* OK, GConf would be nice.
 * Unfortunately the fully-static build does not support GConf process spawn at
 * all. Also /etc/sysconfig directory is standard for the daemon services.
 */


static gboolean verbose=FALSE;


static gboolean try_pairname(const gchar **static_pathname_pointer,const gchar *dirname,const gchar *filename)
{
gchar *pathname;

	g_return_val_if_fail(static_pathname_pointer!=NULL,FALSE);
	g_return_val_if_fail(*static_pathname_pointer==NULL,FALSE);
	g_return_val_if_fail(dirname!=NULL,FALSE);
	g_return_val_if_fail(filename!=NULL,FALSE);

	if (access(dirname,W_OK|X_OK)) {
		if (verbose)
			g_warning(_("Directory not accessible(X) and/or writable(W): %s"),dirname);
		return FALSE;
		}
	pathname=g_strdup_printf("%s/%s",dirname,filename);
	if (access(pathname,R_OK|W_OK) && errno!=ENOENT) {
		if (verbose)
			g_warning(_("Pathname not readable(R) and/or writable(W): %s"),pathname);
		g_free(pathname);
		return FALSE;
		}
	*static_pathname_pointer=pathname;
	return TRUE;
}

G_CONST_RETURN gchar *vpathname_find(const gchar **static_pathname_pointer,va_list ap)
{
	g_return_val_if_fail(static_pathname_pointer!=NULL,NULL);

	if (!*static_pathname_pointer) {
const char *dirname,*filename;
va_list ap_copy;

		G_VA_COPY(ap_copy,ap);
retry:
		while ((dirname=va_arg(ap,const char *))) {
			filename=va_arg(ap,const char *);
			g_assert(filename!=NULL);
			/* Succeeded? */
			if (try_pairname(static_pathname_pointer,dirname,filename))
				break;
			}
		if (!*static_pathname_pointer && !verbose) {
			verbose=TRUE;
			G_VA_COPY(ap,ap_copy);
			goto retry;
			}
		if (!*static_pathname_pointer) {
			g_warning(_("All automatic pathnames failed."));
			*static_pathname_pointer="";
			}
		}
	g_assert(*static_pathname_pointer!=NULL);
	return *static_pathname_pointer;
}

G_CONST_RETURN gchar *pathname_find(const gchar **static_pathname_pointer,...)
{
const gchar *r;
va_list ap;

	g_return_val_if_fail(static_pathname_pointer!=NULL,NULL);

	va_start(ap,static_pathname_pointer);
	r=vpathname_find(static_pathname_pointer,ap);
	va_end(ap);
	return r;
}