freebsd-dev/sys/nfsclient/nfs_lock.c

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/*-
* 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.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>
extern void (*nlminfo_release_p)(struct proc *p);
MALLOC_DEFINE(M_NFSLOCK, "nfsclient_lock", "NFS lock request");
MALLOC_DEFINE(M_NLMINFO, "nfsclient_nlminfo", "NFS lock process structure");
static int nfslockdans(struct thread *td, struct lockd_ans *ansp);
static void nlminfo_release(struct proc *p);
/*
* --------------------------------------------------------------------
* A miniature device driver which the userland uses to talk to us.
*
*/
static struct cdev *nfslock_dev;
static struct mtx nfslock_mtx;
static int nfslock_isopen;
static TAILQ_HEAD(,__lock_msg) nfslock_list;
static int
nfslock_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
int error;
mtx_lock(&nfslock_mtx);
if (!nfslock_isopen) {
error = 0;
nfslock_isopen = 1;
} else {
error = EOPNOTSUPP;
}
mtx_unlock(&nfslock_mtx);
return (error);
}
static int
nfslock_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct __lock_msg *lm;
mtx_lock(&nfslock_mtx);
nfslock_isopen = 0;
while (!TAILQ_EMPTY(&nfslock_list)) {
lm = TAILQ_FIRST(&nfslock_list);
/* XXX: answer request */
TAILQ_REMOVE(&nfslock_list, lm, lm_link);
free(lm, M_NFSLOCK);
}
mtx_unlock(&nfslock_mtx);
return (0);
}
static int
nfslock_read(struct cdev *dev, struct uio *uio, int ioflag)
{
int error;
struct __lock_msg *lm;
if (uio->uio_resid != sizeof *lm)
return (EOPNOTSUPP);
lm = NULL;
error = 0;
mtx_lock(&nfslock_mtx);
while (TAILQ_EMPTY(&nfslock_list)) {
error = msleep(&nfslock_list, &nfslock_mtx, PSOCK | PCATCH,
"nfslockd", 0);
if (error)
break;
}
if (!error) {
lm = TAILQ_FIRST(&nfslock_list);
TAILQ_REMOVE(&nfslock_list, lm, lm_link);
}
mtx_unlock(&nfslock_mtx);
if (!error) {
error = uiomove(lm, sizeof *lm, uio);
free(lm, M_NFSLOCK);
}
return (error);
}
static int
nfslock_write(struct cdev *dev, struct uio *uio, int ioflag)
{
struct lockd_ans la;
int error;
if (uio->uio_resid != sizeof la)
return (EOPNOTSUPP);
error = uiomove(&la, sizeof la, uio);
if (!error)
error = nfslockdans(curthread, &la);
return (error);
}
static int
nfslock_send(struct __lock_msg *lm)
{
struct __lock_msg *lm2;
int error;
error = 0;
lm2 = malloc(sizeof *lm2, M_NFSLOCK, M_WAITOK);
mtx_lock(&nfslock_mtx);
if (nfslock_isopen) {
memcpy(lm2, lm, sizeof *lm2);
TAILQ_INSERT_TAIL(&nfslock_list, lm2, lm_link);
wakeup(&nfslock_list);
} else {
error = EOPNOTSUPP;
}
mtx_unlock(&nfslock_mtx);
if (error)
free(lm2, M_NFSLOCK);
return (error);
}
static struct cdevsw nfslock_cdevsw = {
.d_version = D_VERSION,
.d_open = nfslock_open,
.d_close = nfslock_close,
.d_read = nfslock_read,
.d_write = nfslock_write,
.d_name = "nfslock"
};
static int
nfslock_modevent(module_t mod __unused, int type, void *data __unused)
{
switch (type) {
case MOD_LOAD:
if (bootverbose)
printf("nfslock: pseudo-device\n");
mtx_init(&nfslock_mtx, "nfslock", NULL, MTX_DEF);
TAILQ_INIT(&nfslock_list);
nlminfo_release_p = nlminfo_release;
nfslock_dev = make_dev(&nfslock_cdevsw, 0,
UID_ROOT, GID_KMEM, 0600, _PATH_NFSLCKDEV);
return (0);
default:
return (EOPNOTSUPP);
}
}
DEV_MODULE(nfslock, nfslock_modevent, NULL);
MODULE_VERSION(nfslock, 1);
/*
* 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 thread *td;
struct vnode *vp;
int error;
struct flock *fl;
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_NLMINFO, 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);
for (;;) {
error = nfslock_send(&msg);
if (error)
return (error);
/* Unlocks succeed immediately. */
if (fl->l_type == F_UNLCK)
return (error);
/*
2006-08-16 23:53:05 +00:00
* Retry after 20 seconds if we haven't gotten a response 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.
*/
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;
}
return (error);
}
/*
* nfslockdans --
* NFS advisory byte-level locks answer from the lock daemon.
*/
static 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
o Merge contents of struct pcred into struct ucred. Specifically, add the real uid, saved uid, real gid, and saved gid to ucred, as well as the pcred->pc_uidinfo, which was associated with the real uid, only rename it to cr_ruidinfo so as not to conflict with cr_uidinfo, which corresponds to the effective uid. o Remove p_cred from struct proc; add p_ucred to struct proc, replacing original macro that pointed. p->p_ucred to p->p_cred->pc_ucred. o Universally update code so that it makes use of ucred instead of pcred, p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo, cr_{r,sv}{u,g}id instead of p_*, etc. o Remove pcred0 and its initialization from init_main.c; initialize cr_ruidinfo there. o Restruction many credential modification chunks to always crdup while we figure out locking and optimizations; generally speaking, this means moving to a structure like this: newcred = crdup(oldcred); ... p->p_ucred = newcred; crfree(oldcred); It's not race-free, but better than nothing. There are also races in sys_process.c, all inter-process authorization, fork, exec, and exit. o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid; remove comments indicating that the old arrangement was a problem. o Restructure exec1() a little to use newcred/oldcred arrangement, and use improved uid management primitives. o Clean up exit1() so as to do less work in credential cleanup due to pcred removal. o Clean up fork1() so as to do less work in credential cleanup and allocation. o Clean up ktrcanset() to take into account changes, and move to using suser_xxx() instead of performing a direct uid==0 comparision. o Improve commenting in various kern_prot.c credential modification calls to better document current behavior. In a couple of places, current behavior is a little questionable and we need to check POSIX.1 to make sure it's "right". More commenting work still remains to be done. o Update credential management calls, such as crfree(), to take into account new ruidinfo reference. o Modify or add the following uid and gid helper routines: change_euid() change_egid() change_ruid() change_rgid() change_svuid() change_svgid() In each case, the call now acts on a credential not a process, and as such no longer requires more complicated process locking/etc. They now assume the caller will do any necessary allocation of an exclusive credential reference. Each is commented to document its reference requirements. o CANSIGIO() is simplified to require only credentials, not processes and pcreds. o Remove lots of (p_pcred==NULL) checks. o Add an XXX to authorization code in nfs_lock.c, since it's questionable, and needs to be considered carefully. o Simplify posix4 authorization code to require only credentials, not processes and pcreds. Note that this authorization, as well as CANSIGIO(), needs to be updated to use the p_cansignal() and p_cansched() centralized authorization routines, as they currently do not take into account some desirable restrictions that are handled by the centralized routines, as well as being inconsistent with other similar authorization instances. o Update libkvm to take these changes into account. Obtained from: TrustedBSD Project Reviewed by: green, bde, jhb, freebsd-arch, freebsd-audit
2001-05-25 16:59:11 +00:00
* 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);
}
/*
* Free nlminfo attached to process.
*/
void
nlminfo_release(struct proc *p)
{
free(p->p_nlminfo, M_NLMINFO);
p->p_nlminfo = NULL;
}