/***********************************************************************

*                                                                      *

*               This software is part of the ast package               *

*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

*                      and is licensed under the                       *

*                 Eclipse Public License, Version 1.0                  *

*                    by AT&T Intellectual Property                     *

*                                                                      *

*                A copy of the License is available at                 *

*          http://www.eclipse.org/org/documents/epl-v10.html           *

*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

*                                                                      *

*              Information and Software Systems Research               *

*                            AT&T Research                             *

*                           Florham Park NJ                            *

*                                                                      *

*                 Glenn Fowler <gsf@research.att.com>                  *

*                  David Korn <dgk@research.att.com>                   *

*                   Phong Vo <kpv@research.att.com>                    *

*                                                                      *

***********************************************************************/

#pragma prototyped

/*

 * access() euid/egid implementation

 */

#include <ast.h>

#include <errno.h>

#include <ls.h>

#include "FEATURE/eaccess"

#if _lib_eaccess

NoN(eaccess)

#else

#if defined(__EXPORT__)

#define extern	__EXPORT__

#endif

extern int

eaccess(const char* path, register int flags)

{

#ifdef EFF_ONLY_OK

	return access(path, flags|EFF_ONLY_OK);

#else

#if _lib_euidaccess

	return euidaccess(path, flags);

#else

	register int	mode;

	struct stat	st;

	static int	init;

	static uid_t	ruid;

	static uid_t	euid;

	static gid_t	rgid;

	static gid_t	egid;

	if (!init)

	{

		ruid = getuid();

		euid = geteuid();

		rgid = getgid();

		egid = getegid();

		init = (ruid == euid && rgid == egid) ? 1 : -1;

	}

	if (init > 0 || flags == F_OK)

		return access(path, flags);

	if (stat(path, &st))

		return -1;

	mode = 0;

	if (euid == 0)

	{

		if (!S_ISREG(st.st_mode) || !(flags & X_OK) || (st.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)))

			return 0;

		goto nope;

	}

	else if (euid == st.st_uid)

	{

		if (flags & R_OK)

			mode |= S_IRUSR;

		if (flags & W_OK)

			mode |= S_IWUSR;

		if (flags & X_OK)

			mode |= S_IXUSR;

	}

	else if (egid == st.st_gid)

	{

#if _lib_getgroups

	setgroup:

#endif

		if (flags & R_OK)

			mode |= S_IRGRP;

		if (flags & W_OK)

			mode |= S_IWGRP;

		if (flags & X_OK)

			mode |= S_IXGRP;

	}

	else

	{

#if _lib_getgroups

		register int	n;

		static int	ngroups = -2;

		static gid_t*	groups; 

		if (ngroups == -2)

		{

			if ((ngroups = getgroups(0, (gid_t*)0)) <= 0)

				ngroups = NGROUPS_MAX;

			if (!(groups = newof(0, gid_t, ngroups + 1, 0)))

				ngroups = -1;

			else

				ngroups = getgroups(ngroups, groups);

		}

		n = ngroups;

		while (--n >= 0)

			if (groups[n] == st.st_gid)

				goto setgroup;

#endif

		if (flags & R_OK)

			mode |= S_IROTH;

		if (flags & W_OK)

			mode |= S_IWOTH;

		if (flags & X_OK)

			mode |= S_IXOTH;

	}

	if ((st.st_mode & mode) == mode)

		return 0;

 nope:

	errno = EACCES;

	return -1;

#endif

#endif

}

#endif