400 lines
10 KiB
C
400 lines
10 KiB
C
/*-
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* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from BSDI nfs_lock.c,v 2.4 1998/12/14 23:49:56 jch Exp
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h> /* for hz */
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#include <sys/limits.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/lockf.h> /* for hz */ /* Must come after sys/malloc.h */
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#include <sys/mbuf.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/socket.h>
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#include <sys/socket.h>
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#include <sys/unistd.h>
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#include <sys/vnode.h>
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#include <net/if.h>
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#include <nfs/nfsproto.h>
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#include <nfs/nfs_lock.h>
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#include <nfsclient/nfs.h>
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#include <nfsclient/nfsmount.h>
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#include <nfsclient/nfsnode.h>
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#include <nfsclient/nlminfo.h>
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extern void (*nlminfo_release_p)(struct proc *p);
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vop_advlock_t *nfs_advlock_p = nfs_dolock;
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vop_reclaim_t *nfs_reclaim_p = NULL;
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static MALLOC_DEFINE(M_NFSLOCK, "nfsclient_lock", "NFS lock request");
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static MALLOC_DEFINE(M_NLMINFO, "nfsclient_nlminfo",
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"NFS lock process structure");
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static int nfslockdans(struct thread *td, struct lockd_ans *ansp);
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static void nlminfo_release(struct proc *p);
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/*
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* --------------------------------------------------------------------
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* A miniature device driver which the userland uses to talk to us.
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*
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*/
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static struct cdev *nfslock_dev;
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static struct mtx nfslock_mtx;
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static int nfslock_isopen;
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static TAILQ_HEAD(,__lock_msg) nfslock_list;
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static int
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nfslock_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
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{
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int error;
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error = priv_check(td, PRIV_NFS_LOCKD);
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if (error)
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return (error);
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mtx_lock(&nfslock_mtx);
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if (!nfslock_isopen) {
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error = 0;
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nfslock_isopen = 1;
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} else {
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error = EOPNOTSUPP;
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}
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mtx_unlock(&nfslock_mtx);
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return (error);
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}
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static int
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nfslock_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
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{
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struct __lock_msg *lm;
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mtx_lock(&nfslock_mtx);
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nfslock_isopen = 0;
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while (!TAILQ_EMPTY(&nfslock_list)) {
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lm = TAILQ_FIRST(&nfslock_list);
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/* XXX: answer request */
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TAILQ_REMOVE(&nfslock_list, lm, lm_link);
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free(lm, M_NFSLOCK);
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}
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mtx_unlock(&nfslock_mtx);
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return (0);
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}
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static int
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nfslock_read(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int error;
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struct __lock_msg *lm;
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if (uio->uio_resid != sizeof *lm)
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return (EOPNOTSUPP);
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lm = NULL;
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error = 0;
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mtx_lock(&nfslock_mtx);
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while (TAILQ_EMPTY(&nfslock_list)) {
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error = msleep(&nfslock_list, &nfslock_mtx, PSOCK | PCATCH,
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"nfslockd", 0);
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if (error)
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break;
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}
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if (!error) {
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lm = TAILQ_FIRST(&nfslock_list);
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TAILQ_REMOVE(&nfslock_list, lm, lm_link);
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}
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mtx_unlock(&nfslock_mtx);
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if (!error) {
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error = uiomove(lm, sizeof *lm, uio);
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free(lm, M_NFSLOCK);
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}
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return (error);
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}
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static int
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nfslock_write(struct cdev *dev, struct uio *uio, int ioflag)
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{
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struct lockd_ans la;
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int error;
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if (uio->uio_resid != sizeof la)
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return (EOPNOTSUPP);
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error = uiomove(&la, sizeof la, uio);
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if (!error)
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error = nfslockdans(curthread, &la);
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return (error);
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}
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static int
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nfslock_send(struct __lock_msg *lm)
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{
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struct __lock_msg *lm2;
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int error;
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error = 0;
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lm2 = malloc(sizeof *lm2, M_NFSLOCK, M_WAITOK);
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mtx_lock(&nfslock_mtx);
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if (nfslock_isopen) {
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memcpy(lm2, lm, sizeof *lm2);
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TAILQ_INSERT_TAIL(&nfslock_list, lm2, lm_link);
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wakeup(&nfslock_list);
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} else {
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error = EOPNOTSUPP;
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}
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mtx_unlock(&nfslock_mtx);
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if (error)
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free(lm2, M_NFSLOCK);
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return (error);
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}
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static struct cdevsw nfslock_cdevsw = {
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.d_version = D_VERSION,
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.d_open = nfslock_open,
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.d_close = nfslock_close,
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.d_read = nfslock_read,
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.d_write = nfslock_write,
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.d_name = "nfslock"
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};
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static int
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nfslock_modevent(module_t mod __unused, int type, void *data __unused)
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{
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switch (type) {
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case MOD_LOAD:
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if (bootverbose)
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printf("nfslock: pseudo-device\n");
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mtx_init(&nfslock_mtx, "nfslock", NULL, MTX_DEF);
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TAILQ_INIT(&nfslock_list);
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nlminfo_release_p = nlminfo_release;
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nfslock_dev = make_dev(&nfslock_cdevsw, 0,
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UID_ROOT, GID_KMEM, 0600, _PATH_NFSLCKDEV);
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return (0);
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default:
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return (EOPNOTSUPP);
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}
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}
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DEV_MODULE(nfslock, nfslock_modevent, NULL);
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MODULE_VERSION(nfslock, 1);
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/*
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* XXX
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* We have to let the process know if the call succeeded. I'm using an extra
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* field in the p_nlminfo field in the proc structure, as it is already for
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* lockd stuff.
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*/
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/*
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* nfs_advlock --
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* NFS advisory byte-level locks.
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*
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* The vnode shall be (shared) locked on the entry, it is
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* unconditionally unlocked after.
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*/
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int
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nfs_dolock(struct vop_advlock_args *ap)
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{
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LOCKD_MSG msg;
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struct thread *td;
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struct vnode *vp;
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int error;
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struct flock *fl;
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struct proc *p;
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struct nfsmount *nmp;
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td = curthread;
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p = td->td_proc;
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vp = ap->a_vp;
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fl = ap->a_fl;
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nmp = VFSTONFS(vp->v_mount);
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ASSERT_VOP_LOCKED(vp, "nfs_dolock");
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nmp->nm_getinfo(vp, msg.lm_fh, &msg.lm_fh_len, &msg.lm_addr,
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&msg.lm_nfsv3, NULL, NULL);
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VOP_UNLOCK(vp, 0);
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/*
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* the NLM protocol doesn't allow the server to return an error
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* on ranges, so we do it.
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*/
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if (fl->l_whence != SEEK_END) {
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if ((fl->l_whence != SEEK_CUR && fl->l_whence != SEEK_SET) ||
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fl->l_start < 0 ||
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(fl->l_len < 0 &&
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(fl->l_start == 0 || fl->l_start + fl->l_len < 0)))
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return (EINVAL);
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if (fl->l_len > 0 &&
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(fl->l_len - 1 > OFF_MAX - fl->l_start))
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return (EOVERFLOW);
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}
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/*
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* Fill in the information structure.
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*/
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msg.lm_version = LOCKD_MSG_VERSION;
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msg.lm_msg_ident.pid = p->p_pid;
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mtx_lock(&Giant);
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/*
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* if there is no nfsowner table yet, allocate one.
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*/
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if (p->p_nlminfo == NULL) {
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p->p_nlminfo = malloc(sizeof(struct nlminfo),
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M_NLMINFO, M_WAITOK | M_ZERO);
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p->p_nlminfo->pid_start = p->p_stats->p_start;
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timevaladd(&p->p_nlminfo->pid_start, &boottime);
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}
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msg.lm_msg_ident.pid_start = p->p_nlminfo->pid_start;
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msg.lm_msg_ident.msg_seq = ++(p->p_nlminfo->msg_seq);
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msg.lm_fl = *fl;
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msg.lm_wait = ap->a_flags & F_WAIT;
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msg.lm_getlk = ap->a_op == F_GETLK;
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cru2x(td->td_ucred, &msg.lm_cred);
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for (;;) {
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error = nfslock_send(&msg);
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if (error)
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goto out;
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/* Unlocks succeed immediately. */
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if (fl->l_type == F_UNLCK)
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goto out;
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/*
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* Retry after 20 seconds if we haven't gotten a response yet.
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* This number was picked out of thin air... but is longer
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* then even a reasonably loaded system should take (at least
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* on a local network). XXX Probably should use a back-off
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* scheme.
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*
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* XXX: No PCATCH here since we currently have no useful
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* way to signal to the userland rpc.lockd that the request
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* has been aborted. Once the rpc.lockd implementation
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* can handle aborts, and we report them properly,
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* PCATCH can be put back. In the mean time, if we did
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* permit aborting, the lock attempt would "get lost"
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* and the lock would get stuck in the locked state.
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*/
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error = tsleep(p->p_nlminfo, PUSER, "lockd", 20*hz);
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if (error != 0) {
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if (error == EWOULDBLOCK) {
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/*
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* We timed out, so we rewrite the request
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* to the fifo.
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*/
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continue;
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}
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break;
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}
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if (msg.lm_getlk && p->p_nlminfo->retcode == 0) {
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if (p->p_nlminfo->set_getlk_pid) {
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fl->l_sysid = 0; /* XXX */
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fl->l_pid = p->p_nlminfo->getlk_pid;
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} else {
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fl->l_type = F_UNLCK;
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}
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}
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error = p->p_nlminfo->retcode;
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break;
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}
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out:
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mtx_unlock(&Giant);
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return (error);
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}
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/*
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* nfslockdans --
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* NFS advisory byte-level locks answer from the lock daemon.
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*/
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static int
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nfslockdans(struct thread *td, struct lockd_ans *ansp)
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{
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struct proc *targetp;
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/* the version should match, or we're out of sync */
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if (ansp->la_vers != LOCKD_ANS_VERSION)
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return (EINVAL);
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/* Find the process, set its return errno and wake it up. */
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if ((targetp = pfind(ansp->la_msg_ident.pid)) == NULL)
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return (ESRCH);
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/* verify the pid hasn't been reused (if we can), and it isn't waiting
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* for an answer from a more recent request. We return an EPIPE if
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* the match fails, because we've already used ESRCH above, and this
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* is sort of like writing on a pipe after the reader has closed it.
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*/
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if (targetp->p_nlminfo == NULL ||
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((ansp->la_msg_ident.msg_seq != -1) &&
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(timevalcmp(&targetp->p_nlminfo->pid_start,
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&ansp->la_msg_ident.pid_start, !=) ||
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targetp->p_nlminfo->msg_seq != ansp->la_msg_ident.msg_seq))) {
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PROC_UNLOCK(targetp);
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return (EPIPE);
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}
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targetp->p_nlminfo->retcode = ansp->la_errno;
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targetp->p_nlminfo->set_getlk_pid = ansp->la_set_getlk_pid;
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targetp->p_nlminfo->getlk_pid = ansp->la_getlk_pid;
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wakeup(targetp->p_nlminfo);
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PROC_UNLOCK(targetp);
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return (0);
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}
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/*
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* Free nlminfo attached to process.
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*/
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void
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nlminfo_release(struct proc *p)
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{
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free(p->p_nlminfo, M_NLMINFO);
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p->p_nlminfo = NULL;
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}
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