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/6.2/sys/nfsclient/nfs_lock.c 155631 2006-02-14 00:06:32Z rwatson $");
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/conf.h>
37 #include <sys/fcntl.h>
38 #include <sys/kernel.h> /* for hz */
39 #include <sys/limits.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
43 #include <sys/mbuf.h>
44 #include <sys/mount.h>
45 #include <sys/namei.h>
46 #include <sys/proc.h>
47 #include <sys/resourcevar.h>
48 #include <sys/socket.h>
49 #include <sys/socket.h>
50 #include <sys/unistd.h>
51 #include <sys/vnode.h>
52
53 #include <net/if.h>
54
55 #include <rpc/rpcclnt.h>
56
57 #include <nfs/rpcv2.h>
58 #include <nfs/nfsproto.h>
59 #include <nfsclient/nfs.h>
60 #include <nfsclient/nfsmount.h>
61 #include <nfsclient/nfsnode.h>
62 #include <nfsclient/nfs_lock.h>
63 #include <nfsclient/nlminfo.h>
64
65 extern void (*nlminfo_release_p)(struct proc *p);
66
67 MALLOC_DEFINE(M_NFSLOCK, "NFS lock", "NFS lock request");
68 MALLOC_DEFINE(M_NLMINFO, "nlminfo", "NFS lock process structure");
69
70 static int nfslockdans(struct thread *td, struct lockd_ans *ansp);
71 static void nlminfo_release(struct proc *p);
72 /*
73 * --------------------------------------------------------------------
74 * A miniature device driver which the userland uses to talk to us.
75 *
76 */
77
78 static struct cdev *nfslock_dev;
79 static struct mtx nfslock_mtx;
80 static int nfslock_isopen;
81 static TAILQ_HEAD(,__lock_msg) nfslock_list;
82
83 static int
84 nfslock_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
85 {
86 int error;
87
88 mtx_lock(&nfslock_mtx);
89 if (!nfslock_isopen) {
90 error = 0;
91 nfslock_isopen = 1;
92 } else {
93 error = EOPNOTSUPP;
94 }
95 mtx_unlock(&nfslock_mtx);
96
97 return (error);
98 }
99
100 static int
101 nfslock_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
102 {
103 struct __lock_msg *lm;
104
105 mtx_lock(&nfslock_mtx);
106 nfslock_isopen = 0;
107 while (!TAILQ_EMPTY(&nfslock_list)) {
108 lm = TAILQ_FIRST(&nfslock_list);
109 /* XXX: answer request */
110 TAILQ_REMOVE(&nfslock_list, lm, lm_link);
111 free(lm, M_NFSLOCK);
112 }
113 mtx_unlock(&nfslock_mtx);
114 return (0);
115 }
116
117 static int
118 nfslock_read(struct cdev *dev, struct uio *uio, int ioflag)
119 {
120 int error;
121 struct __lock_msg *lm;
122
123 if (uio->uio_resid != sizeof *lm)
124 return (EOPNOTSUPP);
125 lm = NULL;
126 error = 0;
127 mtx_lock(&nfslock_mtx);
128 while (TAILQ_EMPTY(&nfslock_list)) {
129 error = msleep(&nfslock_list, &nfslock_mtx, PSOCK | PCATCH,
130 "nfslockd", 0);
131 if (error)
132 break;
133 }
134 if (!error) {
135 lm = TAILQ_FIRST(&nfslock_list);
136 TAILQ_REMOVE(&nfslock_list, lm, lm_link);
137 }
138 mtx_unlock(&nfslock_mtx);
139 if (!error) {
140 error = uiomove(lm, sizeof *lm, uio);
141 free(lm, M_NFSLOCK);
142 }
143 return (error);
144 }
145
146 static int
147 nfslock_write(struct cdev *dev, struct uio *uio, int ioflag)
148 {
149 struct lockd_ans la;
150 int error;
151
152 if (uio->uio_resid != sizeof la)
153 return (EOPNOTSUPP);
154 error = uiomove(&la, sizeof la, uio);
155 if (!error)
156 error = nfslockdans(curthread, &la);
157 return (error);
158 }
159
160 static int
161 nfslock_send(struct __lock_msg *lm)
162 {
163 struct __lock_msg *lm2;
164 int error;
165
166 error = 0;
167 lm2 = malloc(sizeof *lm2, M_NFSLOCK, M_WAITOK);
168 mtx_lock(&nfslock_mtx);
169 if (nfslock_isopen) {
170 memcpy(lm2, lm, sizeof *lm2);
171 TAILQ_INSERT_TAIL(&nfslock_list, lm2, lm_link);
172 wakeup(&nfslock_list);
173 } else {
174 error = EOPNOTSUPP;
175 }
176 mtx_unlock(&nfslock_mtx);
177 if (error)
178 free(lm2, M_NFSLOCK);
179 return (error);
180 }
181
182 static struct cdevsw nfslock_cdevsw = {
183 .d_version = D_VERSION,
184 .d_open = nfslock_open,
185 .d_close = nfslock_close,
186 .d_read = nfslock_read,
187 .d_write = nfslock_write,
188 .d_name = "nfslock"
189 };
190
191 static int
192 nfslock_modevent(module_t mod __unused, int type, void *data __unused)
193 {
194
195 switch (type) {
196 case MOD_LOAD:
197 if (bootverbose)
198 printf("nfslock: pseudo-device\n");
199 mtx_init(&nfslock_mtx, "nfslock", NULL, MTX_DEF);
200 TAILQ_INIT(&nfslock_list);
201 nlminfo_release_p = nlminfo_release;
202 nfslock_dev = make_dev(&nfslock_cdevsw, 0,
203 UID_ROOT, GID_KMEM, 0600, _PATH_NFSLCKDEV);
204 return (0);
205 default:
206 return (EOPNOTSUPP);
207 }
208 }
209
210 DEV_MODULE(nfslock, nfslock_modevent, NULL);
211 MODULE_VERSION(nfslock, 1);
212
213
214 /*
215 * XXX
216 * We have to let the process know if the call succeeded. I'm using an extra
217 * field in the p_nlminfo field in the proc structure, as it is already for
218 * lockd stuff.
219 */
220
221 /*
222 * nfs_advlock --
223 * NFS advisory byte-level locks.
224 */
225 int
226 nfs_dolock(struct vop_advlock_args *ap)
227 {
228 LOCKD_MSG msg;
229 struct thread *td;
230 struct vnode *vp;
231 int error;
232 struct flock *fl;
233 struct proc *p;
234
235 td = curthread;
236 p = td->td_proc;
237
238 vp = ap->a_vp;
239 fl = ap->a_fl;
240
241 /*
242 * the NLM protocol doesn't allow the server to return an error
243 * on ranges, so we do it.
244 */
245 if (fl->l_whence != SEEK_END) {
246 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
247 fl->l_start < 0 ||
248 (fl->l_len < 0 &&
249 (fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
250 return (EINVAL);
251 if (fl->l_len > 0 &&
252 (fl->l_len - 1 > OFF_MAX - fl->l_start))
253 return (EOVERFLOW);
254 }
255
256 /*
257 * Fill in the information structure.
258 */
259 msg.lm_version = LOCKD_MSG_VERSION;
260 msg.lm_msg_ident.pid = p->p_pid;
261 /*
262 * if there is no nfsowner table yet, allocate one.
263 */
264 if (p->p_nlminfo == NULL) {
265 MALLOC(p->p_nlminfo, struct nlminfo *,
266 sizeof(struct nlminfo), M_NLMINFO, M_WAITOK | M_ZERO);
267 p->p_nlminfo->pid_start = p->p_stats->p_start;
268 timevaladd(&p->p_nlminfo->pid_start, &boottime);
269 }
270 msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
271 msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
272
273 msg.lm_fl = *fl;
274 msg.lm_wait = ap->a_flags & F_WAIT;
275 msg.lm_getlk = ap->a_op == F_GETLK;
276 bcopy(VFSTONFS(vp->v_mount)->nm_nam, &msg.lm_addr,
277 min(sizeof msg.lm_addr, VFSTONFS(vp->v_mount)->nm_nam->sa_len));
278 msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
279 bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
280 msg.lm_nfsv3 = NFS_ISV3(vp);
281 cru2x(td->td_ucred, &msg.lm_cred);
282
283 for (;;) {
284 error = nfslock_send(&msg);
285 if (error)
286 return (error);
287
288 /* Unlocks succeed immediately. */
289 if (fl->l_type == F_UNLCK)
290 return (error);
291
292 /*
293 * retry after 20 seconds if we haven't gotten a responce yet.
294 * This number was picked out of thin air... but is longer
295 * then even a reasonably loaded system should take (at least
296 * on a local network). XXX Probably should use a back-off
297 * scheme.
298 *
299 * XXX: No PCATCH here since we currently have no useful
300 * way to signal to the userland rpc.lockd that the request
301 * has been aborted. Once the rpc.lockd implementation
302 * can handle aborts, and we report them properly,
303 * PCATCH can be put back. In the mean time, if we did
304 * permit aborting, the lock attempt would "get lost"
305 * and the lock would get stuck in the locked state.
306 */
307 error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz);
308 if (error != 0) {
309 if (error == EWOULDBLOCK) {
310 /*
311 * We timed out, so we rewrite the request
312 * to the fifo.
313 */
314 continue;
315 }
316
317 break;
318 }
319
320 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
321 if (p->p_nlminfo->set_getlk_pid) {
322 fl->l_pid = p->p_nlminfo->getlk_pid;
323 } else {
324 fl->l_type = F_UNLCK;
325 }
326 }
327 error = p->p_nlminfo->retcode;
328 break;
329 }
330
331 return (error);
332 }
333
334 /*
335 * nfslockdans --
336 * NFS advisory byte-level locks answer from the lock daemon.
337 */
338 static int
339 nfslockdans(struct thread *td, struct lockd_ans *ansp)
340 {
341 struct proc *targetp;
342 int error;
343
344 /* Let root, or someone who once was root (lockd generally
345 * switches to the daemon uid once it is done setting up) make
346 * this call.
347 *
348 * XXX This authorization check is probably not right.
349 */
350 if ((error = suser(td)) != 0 &&
351 td->td_ucred->cr_svuid != 0)
352 return (error);
353
354 /* the version should match, or we're out of sync */
355 if (ansp->la_vers != LOCKD_ANS_VERSION)
356 return (EINVAL);
357
358 /* Find the process, set its return errno and wake it up. */
359 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
360 return (ESRCH);
361
362 /* verify the pid hasn't been reused (if we can), and it isn't waiting
363 * for an answer from a more recent request. We return an EPIPE if
364 * the match fails, because we've already used ESRCH above, and this
365 * is sort of like writing on a pipe after the reader has closed it.
366 */
367 if (targetp->p_nlminfo == NULL ||
368 ((ansp->la_msg_ident.msg_seq != -1) &&
369 (timevalcmp(&targetp->p_nlminfo->pid_start,
370 &ansp->la_msg_ident.pid_start, !=) ||
371 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
372 PROC_UNLOCK(targetp);
373 return (EPIPE);
374 }
375
376 targetp->p_nlminfo->retcode = ansp->la_errno;
377 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
378 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
379
380 wakeup(targetp->p_nlminfo);
381
382 PROC_UNLOCK(targetp);
383 return (0);
384 }
385
386 /*
387 * Free nlminfo attached to process.
388 */
389 void
390 nlminfo_release(struct proc *p)
391 {
392 free(p->p_nlminfo, M_NLMINFO);
393 p->p_nlminfo = NULL;
394 }
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