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28 * from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/fcntl.h>
37 #include <sys/kernel.h> /* for hz */
39 #include <sys/malloc.h>
40 #include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
42 #include <sys/mount.h>
43 #include <sys/namei.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>
51 #include <machine/limits.h>
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>
63 #define NFSOWNER_1ST_LEVEL_START 1 /* initial entries */
64 #define NFSOWNER_2ND_LEVEL 256 /* some power of 2 */
66 #define NFSOWNER(tbl, i) \
67 (tbl)[(i) / NFSOWNER_2ND_LEVEL][(i) % NFSOWNER_2ND_LEVEL]
71 * We have to let the process know if the call succeeded. I'm using an extra
72 * field in the p_nlminfo field in the proc structure, as it is already for
78 * NFS advisory byte-level locks.
81 nfs_dolock(struct vop_advlock_args *ap)
86 struct vnode *vp, *wvp;
99 * the NLM protocol doesn't allow the server to return an error
100 * on ranges, so we do it.
102 if (fl->l_whence != SEEK_END) {
103 if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
106 (fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
109 (fl->l_len - 1 > OFF_MAX - fl->l_start))
114 * Fill in the information structure.
116 msg.lm_version = LOCKD_MSG_VERSION;
117 msg.lm_msg_ident.pid = p->p_pid;
119 * if there is no nfsowner table yet, allocate one.
121 if (p->p_nlminfo == NULL) {
122 MALLOC(p->p_nlminfo, struct nlminfo *,
123 sizeof(struct nlminfo), M_LOCKF, M_WAITOK | M_ZERO);
124 p->p_nlminfo->pid_start = p->p_stats->p_start;
126 msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
127 msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
130 msg.lm_wait = ap->a_flags & F_WAIT;
131 msg.lm_getlk = ap->a_op == F_GETLK;
133 * XXX -- I think this is wrong for anything other AF_INET.
135 * XXX: the lm_cred assignment below directly exports a ucred
136 * structure to userland. This is probably wrong, and should at
139 msg.lm_addr = *(VFSTONFS(vp->v_mount)->nm_nam);
140 msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
141 bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
142 msg.lm_nfsv3 = NFS_ISV3(vp);
143 msg.lm_cred = *(td->td_ucred);
146 * Open the lock fifo. If for any reason we don't find the fifo, it
147 * means that the lock daemon isn't running. Translate any missing
148 * file error message for the user, otherwise the application will
149 * complain that the user's file is missing, which isn't the case.
150 * Note that we use proc0's cred, so the fifo is opened as root.
152 * XXX: Note that this behavior is relative to the root directory
153 * of the current process, and this may result in a variety of
154 * {functional, security} problems in chroot() environments.
156 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, _PATH_LCKFIFO, td);
158 fmode = FFLAGS(O_WRONLY);
159 error = vn_open_cred(&nd, &fmode, 0, thread0.td_ucred);
161 return (error == ENOENT ? EOPNOTSUPP : error);
164 VOP_UNLOCK(wvp, 0, td); /* vn_open leaves it locked */
169 VOP_LEASE(wvp, td, thread0.td_ucred, LEASE_WRITE);
171 error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
172 UIO_SYSSPACE, ioflg, thread0.td_ucred, NULL, td);
174 if (error && (((ioflg & IO_NDELAY) == 0) || error != EAGAIN)) {
178 * If we're locking a file, wait for an answer. Unlocks succeed
181 if (fl->l_type == F_UNLCK)
183 * XXX this isn't exactly correct. The client side
184 * needs to continue sending it's unlock until
185 * it gets a responce back.
190 * retry after 20 seconds if we haven't gotten a responce yet.
191 * This number was picked out of thin air... but is longer
192 * then even a reasonably loaded system should take (at least
193 * on a local network). XXX Probably should use a back-off
196 if ((error = tsleep((void *)p->p_nlminfo,
197 PCATCH | PUSER, "lockd", 20*hz)) != 0) {
198 if (error == EWOULDBLOCK) {
200 * We timed out, so we rewrite the request
201 * to the fifo, but only if it isn't already
211 if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
212 if (p->p_nlminfo->set_getlk_pid) {
213 fl->l_pid = p->p_nlminfo->getlk_pid;
215 fl->l_type = F_UNLCK;
218 error = p->p_nlminfo->retcode;
222 if ((error1 = vn_close(wvp, FWRITE, thread0.td_ucred, td)) && error == 0)
230 * NFS advisory byte-level locks answer from the lock daemon.
233 nfslockdans(struct thread *td, struct lockd_ans *ansp)
235 struct proc *targetp;
238 /* Let root, or someone who once was root (lockd generally
239 * switches to the daemon uid once it is done setting up) make
242 * XXX This authorization check is probably not right.
244 if ((error = suser(td->td_proc)) != 0 &&
245 td->td_ucred->cr_svuid != 0)
248 /* the version should match, or we're out of sync */
249 if (ansp->la_vers != LOCKD_ANS_VERSION)
252 /* Find the process, set its return errno and wake it up. */
253 if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
256 /* verify the pid hasn't been reused (if we can), and it isn't waiting
257 * for an answer from a more recent request. We return an EPIPE if
258 * the match fails, because we've already used ESRCH above, and this
259 * is sort of like writing on a pipe after the reader has closed it.
261 if (targetp->p_nlminfo == NULL ||
262 ((ansp->la_msg_ident.msg_seq != -1) &&
263 (timevalcmp(&targetp->p_nlminfo->pid_start,
264 &ansp->la_msg_ident.pid_start, !=) ||
265 targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
266 PROC_UNLOCK(targetp);
270 targetp->p_nlminfo->retcode = ansp->la_errno;
271 targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
272 targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
274 (void)wakeup((void *)targetp->p_nlminfo);
276 PROC_UNLOCK(targetp);