freebsd-dev/sys/nfs/nfs_lock.c

272 lines
7.9 KiB
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
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <net/radix.h>
#include <sys/socket.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/resourcevar.h>
#include <sys/kernel.h> /* for hz */
#include <sys/lockf.h> /* for hz */
#include <net/if.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsmount.h>
#include <nfs/nfsnode.h>
#include <nfs/nfs_lock.h>
#include <nfs/nlminfo.h>
#define NFSOWNER_1ST_LEVEL_START 1 /* initial entries */
#define NFSOWNER_2ND_LEVEL 256 /* some power of 2 */
#define NFSOWNER(tbl, i) \
(tbl)[(i) / NFSOWNER_2ND_LEVEL][(i) % NFSOWNER_2ND_LEVEL]
/*
* 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(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
LOCKD_MSG msg;
struct nameidata nd;
struct proc *p;
uid_t saved_uid;
struct vnode *vp, *wvp;
int error, error1;
struct flock *fl;
int fmode, ioflg;
p = curproc;
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. Note that we should be returning
* EOVERFLOW in some cases, but we don't have it.
*/
if (fl->l_start < 0 || fl->l_len < 0 ||
((fl->l_len != 0 &&
(fl->l_start + fl->l_len - 1) < 0)))
return (EINVAL);
/*
* 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;
}
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;
/*
* XXX -- I think this is wrong for anything other AF_INET.
*/
msg.lm_addr = *(VFSTONFS(vp->v_mount)->nm_nam);
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);
msg.lm_cred = *(p->p_ucred);
/*
* 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.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, _PATH_LCKFIFO, p);
/*
* XXX Hack to temporarily allow this process (regardless of it's creds)
* to open the fifo we need to write to. vn_open() really should
* take a ucred (and once it does, this code should be fixed to use
* proc0's ucred.
*/
saved_uid = p->p_ucred->cr_uid;
p->p_ucred->cr_uid = 0; /* temporarly run the vn_open as root */
fmode = FFLAGS(O_WRONLY);
error = vn_open(&nd, &fmode, 0);
p->p_ucred->cr_uid = saved_uid;
if (error != 0) {
return (error == ENOENT ? EOPNOTSUPP : error);
}
wvp = nd.ni_vp;
VOP_UNLOCK(wvp, 0, p); /* vn_open leaves it locked */
ioflg = IO_UNIT;
for (;;) {
VOP_LEASE(wvp, p, proc0.p_ucred, LEASE_WRITE);
error = vn_rdwr(UIO_WRITE, wvp, (caddr_t)&msg, sizeof(msg), 0,
UIO_SYSSPACE, ioflg, proc0.p_ucred, NULL, p);
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.
*/
if ((error = tsleep((void *)p->p_nlminfo,
PCATCH | PUSER, "lockd", 20*hz)) != 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;
}
if ((error1 = vn_close(wvp, FWRITE, proc0.p_ucred, p)) && error == 0)
return (error1);
return (error);
}
/*
* nfslockdans --
* NFS advisory byte-level locks answer from the lock daemon.
*/
int
nfslockdans(p, ansp)
struct proc *p;
struct lockd_ans *ansp;
{
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
*/
if ((error = suser(p)) != 0 && p->p_cred->p_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 ((p = 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 (p->p_nlminfo == NULL ||
((ansp->la_msg_ident.msg_seq != -1) &&
(timevalcmp(&p->p_nlminfo->pid_start,
&ansp->la_msg_ident.pid_start, !=) ||
p->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq)))
return (EPIPE);
p->p_nlminfo->retcode = ansp->la_errno;
p->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
p->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
(void)wakeup((void *)p->p_nlminfo);
return (0);
}