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/5.1/sys/nfsclient/nfs_lock.c 115415 2003-05-30 17:15:56Z rwatson $");
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/limits.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
42 #include <sys/mbuf.h>
43 #include <sys/mount.h>
44 #include <sys/namei.h>
45 #include <sys/proc.h>
46 #include <sys/resourcevar.h>
47 #include <sys/socket.h>
48 #include <sys/socket.h>
49 #include <sys/unistd.h>
50 #include <sys/vnode.h>
51
52 #include <net/if.h>
53
54 #include <nfs/rpcv2.h>
55 #include <nfs/nfsproto.h>
56 #include <nfsclient/nfs.h>
57 #include <nfsclient/nfsmount.h>
58 #include <nfsclient/nfsnode.h>
59 #include <nfsclient/nfs_lock.h>
60 #include <nfsclient/nlminfo.h>
61
62 /*
63 * XXX
64 * We have to let the process know if the call succeeded. I'm using an extra
65 * field in the p_nlminfo field in the proc structure, as it is already for
66 * lockd stuff.
67 */
68
69 /*
70 * nfs_advlock --
71 * NFS advisory byte-level locks.
72 */
73 int
74 nfs_dolock(struct vop_advlock_args *ap)
75 {
76 LOCKD_MSG msg;
77 struct nameidata nd;
78 struct thread *td;
79 struct vnode *vp, *wvp;
80 int error, error1;
81 struct flock *fl;
82 int fmode, ioflg;
83 struct proc *p;
84
85 td = curthread;
86 p = td->td_proc;
87
88 vp = ap->a_vp;
89 fl = ap->a_fl;
90
91 /*
92 * the NLM protocol doesn't allow the server to return an error
93 * on ranges, so we do it.
94 */
95 if (fl->l_whence != SEEK_END) {
96 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
97 fl->l_start < 0 ||
98 (fl->l_len < 0 &&
99 (fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
100 return (EINVAL);
101 if (fl->l_len > 0 &&
102 (fl->l_len - 1 > OFF_MAX - fl->l_start))
103 return (EOVERFLOW);
104 }
105
106 /*
107 * Fill in the information structure.
108 */
109 msg.lm_version = LOCKD_MSG_VERSION;
110 msg.lm_msg_ident.pid = p->p_pid;
111 /*
112 * if there is no nfsowner table yet, allocate one.
113 */
114 if (p->p_nlminfo == NULL) {
115 MALLOC(p->p_nlminfo, struct nlminfo *,
116 sizeof(struct nlminfo), M_LOCKF, M_WAITOK | M_ZERO);
117 p->p_nlminfo->pid_start = p->p_stats->p_start;
118 timevaladd(&p->p_nlminfo->pid_start, &boottime);
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 | O_NONBLOCK);
147 error = vn_open_cred(&nd, &fmode, 0, thread0.td_ucred);
148 switch (error) {
149 case ENOENT:
150 case ENXIO:
151 /*
152 * Map a failure to find the fifo or no listener on the
153 * fifo to locking not being supported.
154 */
155 return (EOPNOTSUPP);
156 case 0:
157 break;
158 default:
159 return (error);
160 }
161 wvp = nd.ni_vp;
162 VOP_UNLOCK(wvp, 0, td); /* vn_open leaves it locked */
163
164
165 ioflg = IO_UNIT | IO_NOMACCHECK;
166 for (;;) {
167 VOP_LEASE(wvp, td, thread0.td_ucred, LEASE_WRITE);
168
169 error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
170 UIO_SYSSPACE, ioflg, thread0.td_ucred, NOCRED, NULL, td);
171
172 if (error && (((ioflg & IO_NDELAY) == 0) || error != EAGAIN)) {
173 break;
174 }
175 /*
176 * If we're locking a file, wait for an answer. Unlocks succeed
177 * immediately.
178 */
179 if (fl->l_type == F_UNLCK)
180 /*
181 * XXX this isn't exactly correct. The client side
182 * needs to continue sending it's unlock until
183 * it gets a responce back.
184 */
185 break;
186
187 /*
188 * retry after 20 seconds if we haven't gotten a responce yet.
189 * This number was picked out of thin air... but is longer
190 * then even a reasonably loaded system should take (at least
191 * on a local network). XXX Probably should use a back-off
192 * scheme.
193 */
194 error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz);
195 if (error != 0) {
196 if (error == EWOULDBLOCK) {
197 /*
198 * We timed out, so we rewrite the request
199 * to the fifo, but only if it isn't already
200 * full.
201 */
202 ioflg |= IO_NDELAY;
203 continue;
204 }
205
206 break;
207 }
208
209 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
210 if (p->p_nlminfo->set_getlk_pid) {
211 fl->l_pid = p->p_nlminfo->getlk_pid;
212 } else {
213 fl->l_type = F_UNLCK;
214 }
215 }
216 error = p->p_nlminfo->retcode;
217 break;
218 }
219
220 error1 = vn_close(wvp, FWRITE, thread0.td_ucred, td);
221 /* prefer any previous 'error' to our vn_close 'error1'. */
222 return (error != 0 ? error : error1);
223 }
224
225 /*
226 * nfslockdans --
227 * NFS advisory byte-level locks answer from the lock daemon.
228 */
229 int
230 nfslockdans(struct thread *td, struct lockd_ans *ansp)
231 {
232 struct proc *targetp;
233 int error;
234
235 /* Let root, or someone who once was root (lockd generally
236 * switches to the daemon uid once it is done setting up) make
237 * this call.
238 *
239 * XXX This authorization check is probably not right.
240 */
241 if ((error = suser(td)) != 0 &&
242 td->td_ucred->cr_svuid != 0)
243 return (error);
244
245 /* the version should match, or we're out of sync */
246 if (ansp->la_vers != LOCKD_ANS_VERSION)
247 return (EINVAL);
248
249 /* Find the process, set its return errno and wake it up. */
250 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
251 return (ESRCH);
252
253 /* verify the pid hasn't been reused (if we can), and it isn't waiting
254 * for an answer from a more recent request. We return an EPIPE if
255 * the match fails, because we've already used ESRCH above, and this
256 * is sort of like writing on a pipe after the reader has closed it.
257 */
258 if (targetp->p_nlminfo == NULL ||
259 ((ansp->la_msg_ident.msg_seq != -1) &&
260 (timevalcmp(&targetp->p_nlminfo->pid_start,
261 &ansp->la_msg_ident.pid_start, !=) ||
262 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
263 PROC_UNLOCK(targetp);
264 return (EPIPE);
265 }
266
267 targetp->p_nlminfo->retcode = ansp->la_errno;
268 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
269 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
270
271 wakeup(targetp->p_nlminfo);
272
273 PROC_UNLOCK(targetp);
274 return (0);
275 }
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