FreeBSD-5.3/sys/nfsclient/nfs_lock.c
/*-
* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/nfsclient/nfs_lock.c,v 1.39 2003/11/14 20:54:08 alfred Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/kernel.h> /* for hz */
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/socket.h>
#include <sys/socket.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <net/if.h>
#include <rpc/rpcclnt.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfsclient/nfsmount.h>
#include <nfsclient/nfsnode.h>
#include <nfsclient/nfs_lock.h>
#include <nfsclient/nlminfo.h>
/*
* XXX
* We have to let the process know if the call succeeded. I'm using an extra
* field in the p_nlminfo field in the proc structure, as it is already for
* lockd stuff.
*/
/*
* nfs_advlock --
* NFS advisory byte-level locks.
*/
int
nfs_dolock(struct vop_advlock_args *ap)
{
LOCKD_MSG msg;
struct nameidata nd;
struct thread *td;
struct vnode *vp, *wvp;
int error, error1;
struct flock *fl;
int fmode, ioflg;
struct proc *p;
td = curthread;
p = td->td_proc;
vp = ap->a_vp;
fl = ap->a_fl;
/*
* the NLM protocol doesn't allow the server to return an error
* on ranges, so we do it.
*/
if (fl->l_whence != SEEK_END) {
if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
fl->l_start < 0 ||
(fl->l_len < 0 &&
(fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
return (EINVAL);
if (fl->l_len > 0 &&
(fl->l_len - 1 > OFF_MAX - fl->l_start))
return (EOVERFLOW);
}
/*
* Fill in the information structure.
*/
msg.lm_version = LOCKD_MSG_VERSION;
msg.lm_msg_ident.pid = p->p_pid;
/*
* if there is no nfsowner table yet, allocate one.
*/
if (p->p_nlminfo == NULL) {
MALLOC(p->p_nlminfo, struct nlminfo *,
sizeof(struct nlminfo), M_LOCKF, M_WAITOK | M_ZERO);
p->p_nlminfo->pid_start = p->p_stats->p_start;
timevaladd(&p->p_nlminfo->pid_start, &boottime);
}
msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
msg.lm_fl = *fl;
msg.lm_wait = ap->a_flags & F_WAIT;
msg.lm_getlk = ap->a_op == F_GETLK;
bcopy(VFSTONFS(vp->v_mount)->nm_nam, &msg.lm_addr,
min(sizeof msg.lm_addr, VFSTONFS(vp->v_mount)->nm_nam->sa_len));
msg.lm_fh_len = NFS_ISV3(vp) ? VTONFS(vp)->n_fhsize : NFSX_V2FH;
bcopy(VTONFS(vp)->n_fhp, msg.lm_fh, msg.lm_fh_len);
msg.lm_nfsv3 = NFS_ISV3(vp);
cru2x(td->td_ucred, &msg.lm_cred);
/*
* Open the lock fifo. If for any reason we don't find the fifo, it
* means that the lock daemon isn't running. Translate any missing
* file error message for the user, otherwise the application will
* complain that the user's file is missing, which isn't the case.
* Note that we use proc0's cred, so the fifo is opened as root.
*
* XXX: Note that this behavior is relative to the root directory
* of the current process, and this may result in a variety of
* {functional, security} problems in chroot() environments.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, _PATH_LCKFIFO, td);
fmode = FFLAGS(O_WRONLY | O_NONBLOCK);
error = vn_open_cred(&nd, &fmode, 0, thread0.td_ucred, -1);
switch (error) {
case ENOENT:
case ENXIO:
/*
* Map a failure to find the fifo or no listener on the
* fifo to locking not being supported.
*/
return (EOPNOTSUPP);
case 0:
break;
default:
return (error);
}
wvp = nd.ni_vp;
VOP_UNLOCK(wvp, 0, td); /* vn_open leaves it locked */
ioflg = IO_UNIT | IO_NOMACCHECK;
for (;;) {
VOP_LEASE(wvp, td, thread0.td_ucred, LEASE_WRITE);
error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
UIO_SYSSPACE, ioflg, thread0.td_ucred, NOCRED, NULL, td);
if (error && (((ioflg & IO_NDELAY) == 0) || error != EAGAIN)) {
break;
}
/*
* If we're locking a file, wait for an answer. Unlocks succeed
* immediately.
*/
if (fl->l_type == F_UNLCK)
/*
* XXX this isn't exactly correct. The client side
* needs to continue sending it's unlock until
* it gets a responce back.
*/
break;
/*
* retry after 20 seconds if we haven't gotten a responce yet.
* This number was picked out of thin air... but is longer
* then even a reasonably loaded system should take (at least
* on a local network). XXX Probably should use a back-off
* scheme.
*
* XXX: No PCATCH here since we currently have no useful
* way to signal to the userland rpc.lockd that the request
* has been aborted. Once the rpc.lockd implementation
* can handle aborts, and we report them properly,
* PCATCH can be put back. In the mean time, if we did
* permit aborting, the lock attempt would "get lost"
* and the lock would get stuck in the locked state.
*/
error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz);
if (error != 0) {
if (error == EWOULDBLOCK) {
/*
* We timed out, so we rewrite the request
* to the fifo, but only if it isn't already
* full.
*/
ioflg |= IO_NDELAY;
continue;
}
break;
}
if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
if (p->p_nlminfo->set_getlk_pid) {
fl->l_pid = p->p_nlminfo->getlk_pid;
} else {
fl->l_type = F_UNLCK;
}
}
error = p->p_nlminfo->retcode;
break;
}
error1 = vn_close(wvp, FWRITE, thread0.td_ucred, td);
/* prefer any previous 'error' to our vn_close 'error1'. */
return (error != 0 ? error : error1);
}
/*
* nfslockdans --
* NFS advisory byte-level locks answer from the lock daemon.
*/
int
nfslockdans(struct thread *td, struct lockd_ans *ansp)
{
struct proc *targetp;
int error;
/* Let root, or someone who once was root (lockd generally
* switches to the daemon uid once it is done setting up) make
* this call.
*
* XXX This authorization check is probably not right.
*/
if ((error = suser(td)) != 0 &&
td->td_ucred->cr_svuid != 0)
return (error);
/* the version should match, or we're out of sync */
if (ansp->la_vers != LOCKD_ANS_VERSION)
return (EINVAL);
/* Find the process, set its return errno and wake it up. */
if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
return (ESRCH);
/* verify the pid hasn't been reused (if we can), and it isn't waiting
* for an answer from a more recent request. We return an EPIPE if
* the match fails, because we've already used ESRCH above, and this
* is sort of like writing on a pipe after the reader has closed it.
*/
if (targetp->p_nlminfo == NULL ||
((ansp->la_msg_ident.msg_seq != -1) &&
(timevalcmp(&targetp->p_nlminfo->pid_start,
&ansp->la_msg_ident.pid_start, !=) ||
targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
PROC_UNLOCK(targetp);
return (EPIPE);
}
targetp->p_nlminfo->retcode = ansp->la_errno;
targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
wakeup(targetp->p_nlminfo);
PROC_UNLOCK(targetp);
return (0);
}