1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * Portions of this source code were derived from Berkeley 4.3 BSD 31 * under license from the Regents of the University of California. 32 */ 33 34 #pragma ident "%Z%%M% %I% %E% SMI" 35 36 #include <sys/param.h> 37 #include <sys/isa_defs.h> 38 #include <sys/types.h> 39 #include <sys/sysmacros.h> 40 #include <sys/cred_impl.h> 41 #include <sys/systm.h> 42 #include <sys/errno.h> 43 #include <sys/pathname.h> 44 #include <sys/vnode.h> 45 #include <sys/uio.h> 46 #include <sys/cmn_err.h> 47 #include <sys/debug.h> 48 #include <fs/fs_subr.h> 49 50 /* 51 * Determine accessibility of file. 52 */ 53 54 #define E_OK 010 /* use effective ids */ 55 #define R_OK 004 56 #define W_OK 002 57 #define X_OK 001 58 59 int 60 access(char *fname, int fmode) 61 { 62 vnode_t *vp; 63 cred_t *tmpcr; 64 int error; 65 int mode; 66 int eok; 67 cred_t *cr; 68 int estale_retry = 0; 69 70 if (fmode & ~(E_OK|R_OK|W_OK|X_OK)) 71 return (set_errno(EINVAL)); 72 73 mode = ((fmode & (R_OK|W_OK|X_OK)) << 6); 74 75 cr = CRED(); 76 77 /* OK to use effective uid/gid, i.e., no need to crdup(CRED())? */ 78 eok = (fmode & E_OK) || 79 (cr->cr_uid == cr->cr_ruid && cr->cr_gid == cr->cr_rgid); 80 81 if (eok) 82 tmpcr = cr; 83 else { 84 tmpcr = crdup(cr); 85 tmpcr->cr_uid = cr->cr_ruid; 86 tmpcr->cr_gid = cr->cr_rgid; 87 tmpcr->cr_ruid = cr->cr_uid; 88 tmpcr->cr_rgid = cr->cr_gid; 89 } 90 91 lookup: 92 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 93 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 94 goto lookup; 95 if (!eok) 96 crfree(tmpcr); 97 return (set_errno(error)); 98 } 99 100 if (mode) { 101 error = VOP_ACCESS(vp, mode, 0, tmpcr); 102 if (error) { 103 if ((error == ESTALE) && 104 fs_need_estale_retry(estale_retry++)) { 105 VN_RELE(vp); 106 goto lookup; 107 } 108 (void) set_errno(error); 109 } 110 } 111 112 if (!eok) 113 crfree(tmpcr); 114 VN_RELE(vp); 115 return (error); 116 } 117