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("$FreeBSD$");
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/priv.h>
47 #include <sys/proc.h>
48 #include <sys/resourcevar.h>
49 #include <sys/socket.h>
50 #include <sys/socket.h>
51 #include <sys/unistd.h>
52 #include <sys/vnode.h>
53
54 #include <net/if.h>
55
56 #include <rpc/rpcclnt.h>
57
58 #include <nfs/rpcv2.h>
59 #include <nfs/nfsproto.h>
60 #include <nfsclient/nfs.h>
61 #include <nfsclient/nfsmount.h>
62 #include <nfsclient/nfsnode.h>
63 #include <nfsclient/nfs_lock.h>
64 #include <nfsclient/nlminfo.h>
65
66 extern void (*nlminfo_release_p)(struct proc *p);
67
68 MALLOC_DEFINE(M_NFSLOCK, "nfsclient_lock", "NFS lock request");
69 MALLOC_DEFINE(M_NLMINFO, "nfsclient_nlminfo", "NFS lock process structure");
70
71 static int nfslockdans(struct thread *td, struct lockd_ans *ansp);
72 static void nlminfo_release(struct proc *p);
73 /*
74 * --------------------------------------------------------------------
75 * A miniature device driver which the userland uses to talk to us.
76 *
77 */
78
79 static struct cdev *nfslock_dev;
80 static struct mtx nfslock_mtx;
81 static int nfslock_isopen;
82 static TAILQ_HEAD(,__lock_msg) nfslock_list;
83
84 static int
85 nfslock_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
86 {
87 int error;
88
89 error = priv_check(td, PRIV_NFS_LOCKD);
90 if (error)
91 return (error);
92
93 mtx_lock(&nfslock_mtx);
94 if (!nfslock_isopen) {
95 error = 0;
96 nfslock_isopen = 1;
97 } else {
98 error = EOPNOTSUPP;
99 }
100 mtx_unlock(&nfslock_mtx);
101
102 return (error);
103 }
104
105 static int
106 nfslock_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
107 {
108 struct __lock_msg *lm;
109
110 mtx_lock(&nfslock_mtx);
111 nfslock_isopen = 0;
112 while (!TAILQ_EMPTY(&nfslock_list)) {
113 lm = TAILQ_FIRST(&nfslock_list);
114 /* XXX: answer request */
115 TAILQ_REMOVE(&nfslock_list, lm, lm_link);
116 free(lm, M_NFSLOCK);
117 }
118 mtx_unlock(&nfslock_mtx);
119 return (0);
120 }
121
122 static int
123 nfslock_read(struct cdev *dev, struct uio *uio, int ioflag)
124 {
125 int error;
126 struct __lock_msg *lm;
127
128 if (uio->uio_resid != sizeof *lm)
129 return (EOPNOTSUPP);
130 lm = NULL;
131 error = 0;
132 mtx_lock(&nfslock_mtx);
133 while (TAILQ_EMPTY(&nfslock_list)) {
134 error = msleep(&nfslock_list, &nfslock_mtx, PSOCK | PCATCH,
135 "nfslockd", 0);
136 if (error)
137 break;
138 }
139 if (!error) {
140 lm = TAILQ_FIRST(&nfslock_list);
141 TAILQ_REMOVE(&nfslock_list, lm, lm_link);
142 }
143 mtx_unlock(&nfslock_mtx);
144 if (!error) {
145 error = uiomove(lm, sizeof *lm, uio);
146 free(lm, M_NFSLOCK);
147 }
148 return (error);
149 }
150
151 static int
152 nfslock_write(struct cdev *dev, struct uio *uio, int ioflag)
153 {
154 struct lockd_ans la;
155 int error;
156
157 if (uio->uio_resid != sizeof la)
158 return (EOPNOTSUPP);
159 error = uiomove(&la, sizeof la, uio);
160 if (!error)
161 error = nfslockdans(curthread, &la);
162 return (error);
163 }
164
165 static int
166 nfslock_send(struct __lock_msg *lm)
167 {
168 struct __lock_msg *lm2;
169 int error;
170
171 error = 0;
172 lm2 = malloc(sizeof *lm2, M_NFSLOCK, M_WAITOK);
173 mtx_lock(&nfslock_mtx);
174 if (nfslock_isopen) {
175 memcpy(lm2, lm, sizeof *lm2);
176 TAILQ_INSERT_TAIL(&nfslock_list, lm2, lm_link);
177 wakeup(&nfslock_list);
178 } else {
179 error = EOPNOTSUPP;
180 }
181 mtx_unlock(&nfslock_mtx);
182 if (error)
183 free(lm2, M_NFSLOCK);
184 return (error);
185 }
186
187 static struct cdevsw nfslock_cdevsw = {
188 .d_version = D_VERSION,
189 .d_open = nfslock_open,
190 .d_close = nfslock_close,
191 .d_read = nfslock_read,
192 .d_write = nfslock_write,
193 .d_name = "nfslock"
194 };
195
196 static int
197 nfslock_modevent(module_t mod __unused, int type, void *data __unused)
198 {
199
200 switch (type) {
201 case MOD_LOAD:
202 if (bootverbose)
203 printf("nfslock: pseudo-device\n");
204 mtx_init(&nfslock_mtx, "nfslock", NULL, MTX_DEF);
205 TAILQ_INIT(&nfslock_list);
206 nlminfo_release_p = nlminfo_release;
207 nfslock_dev = make_dev(&nfslock_cdevsw, 0,
208 UID_ROOT, GID_KMEM, 0600, _PATH_NFSLCKDEV);
209 return (0);
210 default:
211 return (EOPNOTSUPP);
212 }
213 }
214
215 DEV_MODULE(nfslock, nfslock_modevent, NULL);
216 MODULE_VERSION(nfslock, 1);
217
218
219 /*
220 * XXX
221 * We have to let the process know if the call succeeded. I'm using an extra
222 * field in the p_nlminfo field in the proc structure, as it is already for
223 * lockd stuff.
224 */
225
226 /*
227 * nfs_advlock --
228 * NFS advisory byte-level locks.
229 *
230 * The vnode shall be (shared) locked on the entry, it is
231 * unconditionally unlocked after.
232 */
233 int
234 nfs_dolock(struct vop_advlock_args *ap)
235 {
236 LOCKD_MSG msg;
237 struct thread *td;
238 struct vnode *vp;
239 int error;
240 struct flock *fl;
241 struct proc *p;
242
243 td = curthread;
244 p = td->td_proc;
245
246 vp = ap->a_vp;
247 fl = ap->a_fl;
248
249 ASSERT_VOP_LOCKED(vp, "nfs_dolock");
250
251 bcopy(VFSTONFS(vp->v_mount)->nm_nam, &msg.lm_addr,
252 min(sizeof msg.lm_addr, VFSTONFS(vp->v_mount)->nm_nam->sa_len));
253 msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
254 bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
255 msg.lm_nfsv3 = NFS_ISV3(vp);
256 VOP_UNLOCK(vp, 0, td);
257
258 /*
259 * the NLM protocol doesn't allow the server to return an error
260 * on ranges, so we do it.
261 */
262 if (fl->l_whence != SEEK_END) {
263 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
264 fl->l_start < 0 ||
265 (fl->l_len < 0 &&
266 (fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
267 return (EINVAL);
268 if (fl->l_len > 0 &&
269 (fl->l_len - 1 > OFF_MAX - fl->l_start))
270 return (EOVERFLOW);
271 }
272
273 /*
274 * Fill in the information structure.
275 */
276 msg.lm_version = LOCKD_MSG_VERSION;
277 msg.lm_msg_ident.pid = p->p_pid;
278
279 mtx_lock(&Giant);
280 /*
281 * if there is no nfsowner table yet, allocate one.
282 */
283 if (p->p_nlminfo == NULL) {
284 MALLOC(p->p_nlminfo, struct nlminfo *,
285 sizeof(struct nlminfo), M_NLMINFO, M_WAITOK | M_ZERO);
286 p->p_nlminfo->pid_start = p->p_stats->p_start;
287 timevaladd(&p->p_nlminfo->pid_start, &boottime);
288 }
289 msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
290 msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
291
292 msg.lm_fl = *fl;
293 msg.lm_wait = ap->a_flags & F_WAIT;
294 msg.lm_getlk = ap->a_op == F_GETLK;
295 cru2x(td->td_ucred, &msg.lm_cred);
296
297 for (;;) {
298 error = nfslock_send(&msg);
299 if (error)
300 goto out;
301
302 /* Unlocks succeed immediately. */
303 if (fl->l_type == F_UNLCK)
304 goto out;
305
306 /*
307 * Retry after 20 seconds if we haven't gotten a response yet.
308 * This number was picked out of thin air... but is longer
309 * then even a reasonably loaded system should take (at least
310 * on a local network). XXX Probably should use a back-off
311 * scheme.
312 *
313 * XXX: No PCATCH here since we currently have no useful
314 * way to signal to the userland rpc.lockd that the request
315 * has been aborted. Once the rpc.lockd implementation
316 * can handle aborts, and we report them properly,
317 * PCATCH can be put back. In the mean time, if we did
318 * permit aborting, the lock attempt would "get lost"
319 * and the lock would get stuck in the locked state.
320 */
321 error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz);
322 if (error != 0) {
323 if (error == EWOULDBLOCK) {
324 /*
325 * We timed out, so we rewrite the request
326 * to the fifo.
327 */
328 continue;
329 }
330
331 break;
332 }
333
334 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
335 if (p->p_nlminfo->set_getlk_pid) {
336 fl->l_sysid = 0; /* XXX */
337 fl->l_pid = p->p_nlminfo->getlk_pid;
338 } else {
339 fl->l_type = F_UNLCK;
340 }
341 }
342 error = p->p_nlminfo->retcode;
343 break;
344 }
345 out:
346 mtx_unlock(&Giant);
347 return (error);
348 }
349
350 /*
351 * nfslockdans --
352 * NFS advisory byte-level locks answer from the lock daemon.
353 */
354 static int
355 nfslockdans(struct thread *td, struct lockd_ans *ansp)
356 {
357 struct proc *targetp;
358
359 /* the version should match, or we're out of sync */
360 if (ansp->la_vers != LOCKD_ANS_VERSION)
361 return (EINVAL);
362
363 /* Find the process, set its return errno and wake it up. */
364 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
365 return (ESRCH);
366
367 /* verify the pid hasn't been reused (if we can), and it isn't waiting
368 * for an answer from a more recent request. We return an EPIPE if
369 * the match fails, because we've already used ESRCH above, and this
370 * is sort of like writing on a pipe after the reader has closed it.
371 */
372 if (targetp->p_nlminfo == NULL ||
373 ((ansp->la_msg_ident.msg_seq != -1) &&
374 (timevalcmp(&targetp->p_nlminfo->pid_start,
375 &ansp->la_msg_ident.pid_start, !=) ||
376 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
377 PROC_UNLOCK(targetp);
378 return (EPIPE);
379 }
380
381 targetp->p_nlminfo->retcode = ansp->la_errno;
382 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
383 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
384
385 wakeup(targetp->p_nlminfo);
386
387 PROC_UNLOCK(targetp);
388 return (0);
389 }
390
391 /*
392 * Free nlminfo attached to process.
393 */
394 void
395 nlminfo_release(struct proc *p)
396 {
397 free(p->p_nlminfo, M_NLMINFO);
398 p->p_nlminfo = NULL;
399 }
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