1 /*-
2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Berkeley Software Design Inc's name may not be used to endorse or
13 * promote products derived from this software without specific prior
14 * written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD: releng/5.0/sys/nfsclient/nfs_lock.c 107104 2002-11-20 15:21:06Z alfred $");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/fcntl.h>
37 #include <sys/kernel.h> /* for hz */
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
41 #include <sys/mbuf.h>
42 #include <sys/mount.h>
43 #include <sys/namei.h>
44 #include <sys/proc.h>
45 #include <sys/resourcevar.h>
46 #include <sys/socket.h>
47 #include <sys/socket.h>
48 #include <sys/unistd.h>
49 #include <sys/vnode.h>
50
51 #include <machine/limits.h>
52
53 #include <net/if.h>
54
55 #include <nfs/rpcv2.h>
56 #include <nfs/nfsproto.h>
57 #include <nfsclient/nfs.h>
58 #include <nfsclient/nfsmount.h>
59 #include <nfsclient/nfsnode.h>
60 #include <nfsclient/nfs_lock.h>
61 #include <nfsclient/nlminfo.h>
62
63 /*
64 * XXX
65 * We have to let the process know if the call succeeded. I'm using an extra
66 * field in the p_nlminfo field in the proc structure, as it is already for
67 * lockd stuff.
68 */
69
70 /*
71 * nfs_advlock --
72 * NFS advisory byte-level locks.
73 */
74 int
75 nfs_dolock(struct vop_advlock_args *ap)
76 {
77 LOCKD_MSG msg;
78 struct nameidata nd;
79 struct thread *td;
80 struct vnode *vp, *wvp;
81 int error, error1;
82 struct flock *fl;
83 int fmode, ioflg;
84 struct proc *p;
85
86 td = curthread;
87 p = td->td_proc;
88
89 vp = ap->a_vp;
90 fl = ap->a_fl;
91
92 /*
93 * the NLM protocol doesn't allow the server to return an error
94 * on ranges, so we do it.
95 */
96 if (fl->l_whence != SEEK_END) {
97 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
98 fl->l_start < 0 ||
99 (fl->l_len < 0 &&
100 (fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
101 return (EINVAL);
102 if (fl->l_len > 0 &&
103 (fl->l_len - 1 > OFF_MAX - fl->l_start))
104 return (EOVERFLOW);
105 }
106
107 /*
108 * Fill in the information structure.
109 */
110 msg.lm_version = LOCKD_MSG_VERSION;
111 msg.lm_msg_ident.pid = p->p_pid;
112 /*
113 * if there is no nfsowner table yet, allocate one.
114 */
115 if (p->p_nlminfo == NULL) {
116 MALLOC(p->p_nlminfo, struct nlminfo *,
117 sizeof(struct nlminfo), M_LOCKF, M_WAITOK | M_ZERO);
118 p->p_nlminfo->pid_start = p->p_stats->p_start;
119 }
120 msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
121 msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
122
123 msg.lm_fl = *fl;
124 msg.lm_wait = ap->a_flags & F_WAIT;
125 msg.lm_getlk = ap->a_op == F_GETLK;
126 bcopy(VFSTONFS(vp->v_mount)->nm_nam, &msg.lm_addr,
127 min(sizeof msg.lm_addr, VFSTONFS(vp->v_mount)->nm_nam->sa_len));
128 msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
129 bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
130 msg.lm_nfsv3 = NFS_ISV3(vp);
131 cru2x(td->td_ucred, &msg.lm_cred);
132
133 /*
134 * Open the lock fifo. If for any reason we don't find the fifo, it
135 * means that the lock daemon isn't running. Translate any missing
136 * file error message for the user, otherwise the application will
137 * complain that the user's file is missing, which isn't the case.
138 * Note that we use proc0's cred, so the fifo is opened as root.
139 *
140 * XXX: Note that this behavior is relative to the root directory
141 * of the current process, and this may result in a variety of
142 * {functional, security} problems in chroot() environments.
143 */
144 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, _PATH_LCKFIFO, td);
145
146 fmode = FFLAGS(O_WRONLY);
147 error = vn_open_cred(&nd, &fmode, 0, thread0.td_ucred);
148 if (error != 0) {
149 return (error == ENOENT ? EOPNOTSUPP : error);
150 }
151 wvp = nd.ni_vp;
152 VOP_UNLOCK(wvp, 0, td); /* vn_open leaves it locked */
153
154
155 ioflg = IO_UNIT | IO_NOMACCHECK;
156 for (;;) {
157 VOP_LEASE(wvp, td, thread0.td_ucred, LEASE_WRITE);
158
159 error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
160 UIO_SYSSPACE, ioflg, thread0.td_ucred, NOCRED, NULL, td);
161
162 if (error && (((ioflg & IO_NDELAY) == 0) || error != EAGAIN)) {
163 break;
164 }
165 /*
166 * If we're locking a file, wait for an answer. Unlocks succeed
167 * immediately.
168 */
169 if (fl->l_type == F_UNLCK)
170 /*
171 * XXX this isn't exactly correct. The client side
172 * needs to continue sending it's unlock until
173 * it gets a responce back.
174 */
175 break;
176
177 /*
178 * retry after 20 seconds if we haven't gotten a responce yet.
179 * This number was picked out of thin air... but is longer
180 * then even a reasonably loaded system should take (at least
181 * on a local network). XXX Probably should use a back-off
182 * scheme.
183 */
184 error = tsleep(p->p_nlminfo, PCATCH | PUSER, "lockd", 20*hz);
185 if (error != 0) {
186 if (error == EWOULDBLOCK) {
187 /*
188 * We timed out, so we rewrite the request
189 * to the fifo, but only if it isn't already
190 * full.
191 */
192 ioflg |= IO_NDELAY;
193 continue;
194 }
195
196 break;
197 }
198
199 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
200 if (p->p_nlminfo->set_getlk_pid) {
201 fl->l_pid = p->p_nlminfo->getlk_pid;
202 } else {
203 fl->l_type = F_UNLCK;
204 }
205 }
206 error = p->p_nlminfo->retcode;
207 break;
208 }
209
210 error1 = vn_close(wvp, FWRITE, thread0.td_ucred, td);
211 /* prefer any previous 'error' to our vn_close 'error1'. */
212 return (error != 0 ? error : error1);
213 }
214
215 /*
216 * nfslockdans --
217 * NFS advisory byte-level locks answer from the lock daemon.
218 */
219 int
220 nfslockdans(struct thread *td, struct lockd_ans *ansp)
221 {
222 struct proc *targetp;
223 int error;
224
225 /* Let root, or someone who once was root (lockd generally
226 * switches to the daemon uid once it is done setting up) make
227 * this call.
228 *
229 * XXX This authorization check is probably not right.
230 */
231 if ((error = suser(td)) != 0 &&
232 td->td_ucred->cr_svuid != 0)
233 return (error);
234
235 /* the version should match, or we're out of sync */
236 if (ansp->la_vers != LOCKD_ANS_VERSION)
237 return (EINVAL);
238
239 /* Find the process, set its return errno and wake it up. */
240 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
241 return (ESRCH);
242
243 /* verify the pid hasn't been reused (if we can), and it isn't waiting
244 * for an answer from a more recent request. We return an EPIPE if
245 * the match fails, because we've already used ESRCH above, and this
246 * is sort of like writing on a pipe after the reader has closed it.
247 */
248 if (targetp->p_nlminfo == NULL ||
249 ((ansp->la_msg_ident.msg_seq != -1) &&
250 (timevalcmp(&targetp->p_nlminfo->pid_start,
251 &ansp->la_msg_ident.pid_start, !=) ||
252 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
253 PROC_UNLOCK(targetp);
254 return (EPIPE);
255 }
256
257 targetp->p_nlminfo->retcode = ansp->la_errno;
258 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
259 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
260
261 wakeup(targetp->p_nlminfo);
262
263 PROC_UNLOCK(targetp);
264 return (0);
265 }
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