/* @(#)rename.c	1.11 11/06/18 Copyright 1998-2011 J. Schilling */
#include <schily/mconfig.h>
#ifndef lint
static	UConst char sccsid[] =
	"@(#)rename.c	1.11 11/06/18 Copyright 1998-2011 J. Schilling";
#endif
/*
 *	rename() for old systems that don't have it.
 *
 *	Copyright (c) 1998-2011 J. Schilling
 */
/*
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * See the file CDDL.Schily.txt in this distribution for details.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file CDDL.Schily.txt from this distribution.
 */

#define	rename	__nothing__
#include <schily/mconfig.h>

#ifndef	HAVE_RENAME

#include <schily/stdio.h>	/* XXX not OK but needed for js_xx() in schily/schily.h */
#include <schily/stdlib.h>
#include <schily/unistd.h>
#include <schily/string.h>
#include <schily/stat.h>
#include <schily/maxpath.h>
#include <schily/standard.h>
#include <schily/utypes.h>
#include <schily/schily.h>
#include <schily/errno.h>
#undef	rename
#include <schily/libport.h>

#ifndef	MAXPATHNAME
#define	MAXPATHNAME	1024
#endif

#if	MAXPATHNAME < 1024
#undef	MAXPATHNAME
#define	MAXPATHNAME	1024
#endif

#define	MAXNAME	MAXPATHNAME

#define	FILEDESC struct stat

#ifndef	HAVE_LSTAT
#define	lstat	stat
#endif

EXPORT int
rename(old, new)
	const char	*old;
	const char	*new;
{
	char	bakname[MAXNAME];
	char	*p;
	char	strpid[32];
	int	strplen;
	int	plen;
	BOOL	savpresent = FALSE;
	BOOL	newpresent = FALSE;
	int	serrno;
	FILEDESC ostat;
	FILEDESC xstat;

	serrno = geterrno();

	if (lstat(old, &ostat) < 0)
		return (-1);

	if (lstat(new, &xstat) >= 0) {
		newpresent = TRUE;
		if (ostat.st_dev == xstat.st_dev &&
		    ostat.st_ino == xstat.st_ino)
			return (0);		/* old == new we are done */
	}

#ifndef	HAVE_MKTEMP
	strplen = js_snprintf(strpid, sizeof (strpid), ".%llx",
							(Llong)getpid());
#else
	strplen = 6;
	strcpy(strpid, "XXXXXX");
#endif

	/*
	 * Save old version of file 'new' to allow us to restore it.
	 * Platforms without rename() usually only support short filenames
	 * but limit pid to 32000.
	 */
	strlcpy(bakname, new, MAXNAME-strplen);
	p = strrchr(bakname, '/');
	if (p == NULL)
		p = bakname;
	else
		p++;
	plen = strlen(p);
	if ((plen + strplen) > 14)
		p[14-strplen] = '\0';
	strcat(p, strpid);
#ifdef	HAVE_MKTEMP
	mktemp(bakname);
#endif
	if (bakname[0] != '\0' && link(new, bakname) >= 0)
		savpresent = TRUE;

	if (newpresent) {
		if (rmdir(new) < 0) {
			if (geterrno() == ENOTDIR) {
				if (unlink(new) < 0)
					return (-1);
			} else {
				return (-1);
			}
		}
	}

	/*
	 * Now add 'new' name to 'old'.
	 */
	if (link(old, new) < 0) {
		serrno = geterrno();
		/*
		 * Make sure not to loose old version of 'new'.
		 */
		if (savpresent) {
			unlink(new);
			link(bakname, new);
			unlink(bakname);
		}
		seterrno(serrno);
		return (-1);
	}
	if (unlink(old) < 0)
		return (-1);
	if (savpresent)
		unlink(bakname);	/* Fails in most cases...	*/
	seterrno(serrno);		/* ...so restore errno		*/
	return (0);
}
#endif	/* HAVE_RENAME */