17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
57c478bd9Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
67c478bd9Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
77c478bd9Sstevel@tonic-gate * with the License.
87c478bd9Sstevel@tonic-gate *
97c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
107c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
117c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
127c478bd9Sstevel@tonic-gate * and limitations under the License.
137c478bd9Sstevel@tonic-gate *
147c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
157c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
167c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
177c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
187c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
197c478bd9Sstevel@tonic-gate *
207c478bd9Sstevel@tonic-gate * CDDL HEADER END
217c478bd9Sstevel@tonic-gate */
227c478bd9Sstevel@tonic-gate /*
239a34c4c9Skucharsk * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
247c478bd9Sstevel@tonic-gate * Use is subject to license terms.
25*7eb8c88aSAndy Fiddaman * Copyright 2021 OmniOS Community Edition (OmniOSce) Association.
267c478bd9Sstevel@tonic-gate */
277c478bd9Sstevel@tonic-gate
287c478bd9Sstevel@tonic-gate #include <sys/copyops.h>
297c478bd9Sstevel@tonic-gate #include <sys/errno.h>
307c478bd9Sstevel@tonic-gate #include <sys/kmem.h>
317c478bd9Sstevel@tonic-gate #include <sys/param.h>
327c478bd9Sstevel@tonic-gate #include <sys/pathname.h>
337c478bd9Sstevel@tonic-gate #include <sys/sysmacros.h>
347c478bd9Sstevel@tonic-gate #include <sys/systm.h>
357c478bd9Sstevel@tonic-gate #include <sys/types.h>
367c478bd9Sstevel@tonic-gate #include <sys/vnode.h>
377c478bd9Sstevel@tonic-gate
387c478bd9Sstevel@tonic-gate int
getcwd(char * buf,size_t buflen)397c478bd9Sstevel@tonic-gate getcwd(char *buf, size_t buflen)
407c478bd9Sstevel@tonic-gate {
419a34c4c9Skucharsk int err;
427c478bd9Sstevel@tonic-gate char *kbuf;
437c478bd9Sstevel@tonic-gate size_t kbuflen;
447c478bd9Sstevel@tonic-gate
457c478bd9Sstevel@tonic-gate /*
46*7eb8c88aSAndy Fiddaman * If the buffer cannot accommodate one character and nul terminator,
47*7eb8c88aSAndy Fiddaman * it is too small.
48*7eb8c88aSAndy Fiddaman */
49*7eb8c88aSAndy Fiddaman if (buflen < 2)
50*7eb8c88aSAndy Fiddaman return (set_errno(ERANGE));
51*7eb8c88aSAndy Fiddaman
52*7eb8c88aSAndy Fiddaman /*
537c478bd9Sstevel@tonic-gate * The user should be able to specify any size buffer, but we don't want
547c478bd9Sstevel@tonic-gate * to arbitrarily allocate huge kernel buffers just because the user
557c478bd9Sstevel@tonic-gate * requests it. So we'll start with MAXPATHLEN (which should hold any
56*7eb8c88aSAndy Fiddaman * normal path), and only increase it if we fail with
57*7eb8c88aSAndy Fiddaman * ERANGE / ENAMETOOLONG.
58*7eb8c88aSAndy Fiddaman *
59*7eb8c88aSAndy Fiddaman * To protect against unbounded memory usage, cap to kmem_max_cached.
60*7eb8c88aSAndy Fiddaman * This is far bigger than the length of any practical path on the
61*7eb8c88aSAndy Fiddaman * system, and avoids allocating memory from the kmem_oversized arena.
627c478bd9Sstevel@tonic-gate */
637c478bd9Sstevel@tonic-gate kbuflen = MIN(buflen, MAXPATHLEN);
647c478bd9Sstevel@tonic-gate
65*7eb8c88aSAndy Fiddaman while (kbuflen <= kmem_max_cached) {
667c478bd9Sstevel@tonic-gate kbuf = kmem_alloc(kbuflen, KM_SLEEP);
677c478bd9Sstevel@tonic-gate
689a34c4c9Skucharsk if (((err = dogetcwd(kbuf, kbuflen)) == 0) &&
69*7eb8c88aSAndy Fiddaman (copyout(kbuf, buf, strlen(kbuf) + 1) != 0)) {
709a34c4c9Skucharsk err = EFAULT;
71*7eb8c88aSAndy Fiddaman }
727c478bd9Sstevel@tonic-gate
737c478bd9Sstevel@tonic-gate kmem_free(kbuf, kbuflen);
747c478bd9Sstevel@tonic-gate
75*7eb8c88aSAndy Fiddaman /*
76*7eb8c88aSAndy Fiddaman * dogetcwd() inconsistently returns ERANGE or ENAMETOOLONG
77*7eb8c88aSAndy Fiddaman * depending on whether it calls dirtopath() and then whether
78*7eb8c88aSAndy Fiddaman * the subsequent operations run out of space whilst
79*7eb8c88aSAndy Fiddaman * evaluating a cached vnode path or otherwise.
80*7eb8c88aSAndy Fiddaman */
81*7eb8c88aSAndy Fiddaman if (err == ENAMETOOLONG || err == ERANGE) {
82*7eb8c88aSAndy Fiddaman /* For some reason, getcwd() uses ERANGE. */
83*7eb8c88aSAndy Fiddaman err = ERANGE;
847c478bd9Sstevel@tonic-gate /*
857c478bd9Sstevel@tonic-gate * If the user's buffer really was too small, give up.
867c478bd9Sstevel@tonic-gate */
87*7eb8c88aSAndy Fiddaman if (kbuflen == buflen)
887c478bd9Sstevel@tonic-gate break;
897c478bd9Sstevel@tonic-gate kbuflen = MIN(kbuflen * 2, buflen);
907c478bd9Sstevel@tonic-gate } else {
917c478bd9Sstevel@tonic-gate break;
927c478bd9Sstevel@tonic-gate }
937c478bd9Sstevel@tonic-gate }
947c478bd9Sstevel@tonic-gate
959a34c4c9Skucharsk return ((err != 0) ? set_errno(err) : 0);
967c478bd9Sstevel@tonic-gate }
97