1 /* $OpenBSD: linux_getcwd.c,v 1.2 2001/05/16 12:50:21 ho Exp $ */
2 /* $NetBSD: vfs_getcwd.c,v 1.3.2.3 1999/07/11 10:24:09 sommerfeld Exp $ */
4 * Copyright (c) 1999 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include "opt_compat.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/namei.h>
47 #include <sys/filedesc.h>
48 #include <sys/kernel.h>
51 #include <sys/syscallsubr.h>
52 #include <sys/vnode.h>
53 #include <sys/mount.h>
56 #include <sys/malloc.h>
57 #include <sys/dirent.h>
58 #include <ufs/ufs/dir.h> /* XXX only for DIRBLKSIZ */
61 #include <machine/../linux32/linux.h>
62 #include <machine/../linux32/linux32_proto.h>
64 #include <machine/../linux/linux.h>
65 #include <machine/../linux/linux_proto.h>
67 #include <compat/linux/linux_util.h>
69 #include <security/mac/mac_framework.h>
72 linux_getcwd_scandir(struct vnode **, struct vnode **,
73 char **, char *, struct thread *);
75 linux_getcwd_common(struct vnode *, struct vnode *,
76 char **, char *, int, int, struct thread *);
78 #define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
81 * Vnode variable naming conventions in this file:
83 * rvp: the current root we're aiming towards.
84 * lvp, *lvpp: the "lower" vnode
85 * uvp, *uvpp: the "upper" vnode.
87 * Since all the vnodes we're dealing with are directories, and the
88 * lookups are going *up* in the filesystem rather than *down*, the
89 * usual "pvp" (parent) or "dvp" (directory) naming conventions are
94 * XXX Will infinite loop in certain cases if a directory read reliably
95 * returns EINVAL on last block.
96 * XXX is EINVAL the right thing to return if a directory is malformed?
100 * XXX Untested vs. mount -o union; probably does the wrong thing.
104 * Find parent vnode of *lvpp, return in *uvpp
106 * If we care about the name, scan it looking for name of directory
107 * entry pointing at lvp.
109 * Place the name in the buffer which starts at bufp, immediately
110 * before *bpp, and move bpp backwards to point at the start of it.
112 * On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
113 * On exit, *uvpp is either NULL or is a locked vnode reference.
116 linux_getcwd_scandir(lvpp, uvpp, bpp, bufp, td)
133 struct vnode *uvp = NULL;
134 struct vnode *lvp = *lvpp;
135 struct componentname cn;
140 * If we want the filename, get some info we need while the
141 * current directory is still locked.
144 error = VOP_GETATTR(lvp, &va, td->td_ucred);
154 * Ok, we have to do it the hard way..
155 * Next, get parent vnode using lookup of ..
157 cn.cn_nameiop = LOOKUP;
158 cn.cn_flags = ISLASTCN | ISDOTDOT | RDONLY;
160 cn.cn_cred = td->td_ucred;
162 cn.cn_nameptr = "..";
165 cn.cn_lkflags = LK_SHARED;
168 * At this point, lvp is locked and will be unlocked by the lookup.
169 * On successful return, *uvpp will be locked
172 error = mac_vnode_check_lookup(td->td_ucred, lvp, &cn);
175 error = VOP_LOOKUP(lvp, uvpp, &cn);
184 /* If we don't care about the pathname, we're done */
191 fileno = va.va_fileid;
193 dirbuflen = DIRBLKSIZ;
194 if (dirbuflen < va.va_blocksize)
195 dirbuflen = va.va_blocksize;
196 dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
203 /* call VOP_READDIR of parent */
204 iov.iov_base = dirbuf;
205 iov.iov_len = dirbuflen;
209 uio.uio_offset = off;
210 uio.uio_resid = dirbuflen;
211 uio.uio_segflg = UIO_SYSSPACE;
212 uio.uio_rw = UIO_READ;
218 error = mac_vnode_check_readdir(td->td_ucred, uvp);
221 error = VOP_READDIR(uvp, &uio, td->td_ucred, &eofflag,
224 off = uio.uio_offset;
227 * Try again if NFS tosses its cookies.
228 * XXX this can still loop forever if the directory is busted
229 * such that the second or subsequent page of it always
232 if ((error == EINVAL) && (tries < 3)) {
235 continue; /* once more, with feeling */
245 /* scan directory page looking for matching vnode */
246 for (len = (dirbuflen - uio.uio_resid); len > 0; len -= reclen) {
247 dp = (struct dirent *) cpos;
248 reclen = dp->d_reclen;
250 /* check for malformed directory.. */
251 if (reclen < DIRENT_MINSIZE) {
256 * XXX should perhaps do VOP_LOOKUP to
257 * check that we got back to the right place,
258 * but getting the locking games for that
259 * right would be heinous.
261 if ((dp->d_type != DT_WHT) &&
262 (dp->d_fileno == fileno)) {
270 bcopy(dp->d_name, bp, dp->d_namlen);
284 free(dirbuf, M_TEMP);
290 * common routine shared by sys___getcwd() and linux_vn_isunder()
293 #define GETCWD_CHECK_ACCESS 0x0001
296 linux_getcwd_common (lvp, rvp, bpp, bufp, limit, flags, td)
305 struct filedesc *fdp = td->td_proc->p_fd;
306 struct vnode *uvp = NULL;
309 accmode_t accmode = VEXEC;
321 * Error handling invariant:
322 * Before a `goto out':
323 * lvp is either NULL, or locked and held.
324 * uvp is either NULL, or locked and held.
327 error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY);
329 panic("vn_lock LK_RETRY returned error %d", error);
333 * this loop will terminate when one of the following happens:
335 * - getdirentries or lookup fails
336 * - we run out of space in the buffer.
344 if (lvp->v_type != VDIR) {
350 * access check here is optional, depending on
351 * whether or not caller cares.
353 if (flags & GETCWD_CHECK_ACCESS) {
354 error = VOP_ACCESS(lvp, accmode, td->td_ucred, td);
357 accmode = VEXEC|VREAD;
361 * step up if we're a covered vnode..
363 while (lvp->v_vflag & VV_ROOT) {
370 lvp = lvp->v_mount->mnt_vnodecovered;
373 * hodie natus est radici frater
380 error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY);
382 panic("vn_lock LK_RETRY returned %d", error);
384 error = linux_getcwd_scandir(&lvp, &uvp, &bp, bufp, td);
389 panic("getcwd: oops, forgot to null lvp");
390 if (bufp && (bp <= bufp)) {
391 panic("getcwd: oops, went back too far");
399 } while ((lvp != rvp) && (limit > 0));
414 * Find pathname of process's current directory.
416 * Use vfs vnode-to-name reverse cache; if that fails, fall back
417 * to reading directory contents.
421 linux_getcwd(struct thread *td, struct linux_getcwd_args *args)
423 caddr_t bp, bend, path;
424 int error, len, lenused;
428 printf(ARGS(getcwd, "%p, %ld"), args->buf, (long)args->bufsize);
433 if (len > MAXPATHLEN*4)
438 path = (char *)malloc(len, M_TEMP, M_WAITOK);
440 error = kern___getcwd(td, path, UIO_SYSSPACE, len);
442 lenused = strlen(path) + 1;
443 if (lenused <= args->bufsize) {
444 td->td_retval[0] = lenused;
445 error = copyout(path, args->buf, lenused);
455 * 5th argument here is "max number of vnodes to traverse".
456 * Since each entry takes up at least 2 bytes in the output buffer,
457 * limit it to N/2 vnodes for an N byte buffer.
461 error = linux_getcwd_common (td->td_proc->p_fd->fd_cdir, NULL,
462 &bp, path, len/2, GETCWD_CHECK_ACCESS, td);
468 td->td_retval[0] = lenused;
469 /* put the result into user buffer */
470 error = copyout(bp, args->buf, lenused);