1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
28*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate /*
31*0Sstevel@tonic-gate  * Portions of this source code were derived from Berkeley 4.3 BSD
32*0Sstevel@tonic-gate  * under license from the Regents of the University of California.
33*0Sstevel@tonic-gate  */
34*0Sstevel@tonic-gate 
35*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
36*0Sstevel@tonic-gate 
37*0Sstevel@tonic-gate #include <sys/param.h>
38*0Sstevel@tonic-gate #include <sys/isa_defs.h>
39*0Sstevel@tonic-gate #include <sys/types.h>
40*0Sstevel@tonic-gate #include <sys/sysmacros.h>
41*0Sstevel@tonic-gate #include <sys/cred_impl.h>
42*0Sstevel@tonic-gate #include <sys/systm.h>
43*0Sstevel@tonic-gate #include <sys/errno.h>
44*0Sstevel@tonic-gate #include <sys/pathname.h>
45*0Sstevel@tonic-gate #include <sys/vnode.h>
46*0Sstevel@tonic-gate #include <sys/uio.h>
47*0Sstevel@tonic-gate #include <sys/cmn_err.h>
48*0Sstevel@tonic-gate #include <sys/debug.h>
49*0Sstevel@tonic-gate 
50*0Sstevel@tonic-gate /*
51*0Sstevel@tonic-gate  * Determine accessibility of file.
52*0Sstevel@tonic-gate  */
53*0Sstevel@tonic-gate 
54*0Sstevel@tonic-gate #define	E_OK	010	/* use effective ids */
55*0Sstevel@tonic-gate #define	R_OK	004
56*0Sstevel@tonic-gate #define	W_OK	002
57*0Sstevel@tonic-gate #define	X_OK	001
58*0Sstevel@tonic-gate 
59*0Sstevel@tonic-gate int
60*0Sstevel@tonic-gate access(char *fname, int fmode)
61*0Sstevel@tonic-gate {
62*0Sstevel@tonic-gate 	vnode_t *vp;
63*0Sstevel@tonic-gate 	cred_t *tmpcr;
64*0Sstevel@tonic-gate 	int error;
65*0Sstevel@tonic-gate 	int mode;
66*0Sstevel@tonic-gate 	int eok;
67*0Sstevel@tonic-gate 	cred_t *cr;
68*0Sstevel@tonic-gate 
69*0Sstevel@tonic-gate 	if (fmode & ~(E_OK|R_OK|W_OK|X_OK))
70*0Sstevel@tonic-gate 		return (set_errno(EINVAL));
71*0Sstevel@tonic-gate 
72*0Sstevel@tonic-gate 	mode = ((fmode & (R_OK|W_OK|X_OK)) << 6);
73*0Sstevel@tonic-gate 
74*0Sstevel@tonic-gate 	cr = CRED();
75*0Sstevel@tonic-gate 
76*0Sstevel@tonic-gate 	/* OK to use effective uid/gid, i.e., no need to crdup(CRED())? */
77*0Sstevel@tonic-gate 	eok = (fmode & E_OK) ||
78*0Sstevel@tonic-gate 		(cr->cr_uid == cr->cr_ruid && cr->cr_gid == cr->cr_rgid);
79*0Sstevel@tonic-gate 
80*0Sstevel@tonic-gate 	if (eok)
81*0Sstevel@tonic-gate 		tmpcr = cr;
82*0Sstevel@tonic-gate 	else {
83*0Sstevel@tonic-gate 		tmpcr = crdup(cr);
84*0Sstevel@tonic-gate 		tmpcr->cr_uid = cr->cr_ruid;
85*0Sstevel@tonic-gate 		tmpcr->cr_gid = cr->cr_rgid;
86*0Sstevel@tonic-gate 		tmpcr->cr_ruid = cr->cr_uid;
87*0Sstevel@tonic-gate 		tmpcr->cr_rgid = cr->cr_gid;
88*0Sstevel@tonic-gate 	}
89*0Sstevel@tonic-gate 
90*0Sstevel@tonic-gate lookup:
91*0Sstevel@tonic-gate 	if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) {
92*0Sstevel@tonic-gate 		if (error == ESTALE)
93*0Sstevel@tonic-gate 			goto lookup;
94*0Sstevel@tonic-gate 		if (!eok)
95*0Sstevel@tonic-gate 			crfree(tmpcr);
96*0Sstevel@tonic-gate 		return (set_errno(error));
97*0Sstevel@tonic-gate 	}
98*0Sstevel@tonic-gate 
99*0Sstevel@tonic-gate 	if (mode) {
100*0Sstevel@tonic-gate 		error = VOP_ACCESS(vp, mode, 0, tmpcr);
101*0Sstevel@tonic-gate 		if (error) {
102*0Sstevel@tonic-gate 			if (error == ESTALE) {
103*0Sstevel@tonic-gate 				VN_RELE(vp);
104*0Sstevel@tonic-gate 				goto lookup;
105*0Sstevel@tonic-gate 			}
106*0Sstevel@tonic-gate 			(void) set_errno(error);
107*0Sstevel@tonic-gate 		}
108*0Sstevel@tonic-gate 	}
109*0Sstevel@tonic-gate 
110*0Sstevel@tonic-gate 	if (!eok)
111*0Sstevel@tonic-gate 		crfree(tmpcr);
112*0Sstevel@tonic-gate 	VN_RELE(vp);
113*0Sstevel@tonic-gate 	return (error);
114*0Sstevel@tonic-gate }
115