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38363c022a
NetBSD/sys/kern/uipc_usrreq.c
christos f2a172afbf Avoid crash dereferencing a NULL fp in fd_affix() in unp_externalize 
caused by the sequence of passing two fd's with two sendmsg()'s,
then doing a read() and a recvmsg(). The read() calls dom_dispose()
which discards both messages in the mbuf, and sets the fp's in the
array to NULL. Linux dequeues only one message per read() so the
second recvmsg() gets the fd from the second message.  This fix
just avoids the NULL pointer de-reference, making the second
recvmsg() to fail. It is dubious to pass fd's with stream sockets
and expect mixing read() and recvmsg() to work. Plus processing
one control message per read() changes the current semantics and
should be examined before applied. In addition there is a race between
dom_externalize() and dom_dispose(): what happens in a multi-threaded
network stack when one thread disposes where the other externalizes
the same array?

NB: Pullup to 6.
2012-10-06 22:58:08 +00:00

1833 lines
45 KiB
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/* $NetBSD: uipc_usrreq.c,v 1.140 2012/10/06 22:58:08 christos Exp $ */
/*-
* Copyright (c) 1998, 2000, 2004, 2008, 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, and by Andrew Doran.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 THE FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95
*/
/*
* Copyright (c) 1997 Christopher G. Demetriou. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.140 2012/10/06 22:58:08 christos Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/unpcb.h>
#include <sys/un.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mbuf.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
#include <sys/atomic.h>
#include <sys/uidinfo.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
/*
* Unix communications domain.
*
* TODO:
* RDM
* rethink name space problems
* need a proper out-of-band
*
* Notes on locking:
*
* The generic rules noted in uipc_socket2.c apply. In addition:
*
* o We have a global lock, uipc_lock.
*
* o All datagram sockets are locked by uipc_lock.
*
* o For stream socketpairs, the two endpoints are created sharing the same
* independent lock. Sockets presented to PRU_CONNECT2 must already have
* matching locks.
*
* o Stream sockets created via socket() start life with their own
* independent lock.
*
* o Stream connections to a named endpoint are slightly more complicated.
* Sockets that have called listen() have their lock pointer mutated to
* the global uipc_lock. When establishing a connection, the connecting
* socket also has its lock mutated to uipc_lock, which matches the head
* (listening socket). We create a new socket for accept() to return, and
* that also shares the head's lock. Until the connection is completely
* done on both ends, all three sockets are locked by uipc_lock. Once the
* connection is complete, the association with the head's lock is broken.
* The connecting socket and the socket returned from accept() have their
* lock pointers mutated away from uipc_lock, and back to the connecting
* socket's original, independent lock. The head continues to be locked
* by uipc_lock.
*
* o If uipc_lock is determined to be a significant source of contention,
* it could easily be hashed out. It is difficult to simply make it an
* independent lock because of visibility / garbage collection issues:
* if a socket has been associated with a lock at any point, that lock
* must remain valid until the socket is no longer visible in the system.
* The lock must not be freed or otherwise destroyed until any sockets
* that had referenced it have also been destroyed.
*/
const struct sockaddr_un sun_noname = {
.sun_len = sizeof(sun_noname),
.sun_family = AF_LOCAL,
};
ino_t unp_ino; /* prototype for fake inode numbers */
struct mbuf *unp_addsockcred(struct lwp *, struct mbuf *);
static void unp_mark(file_t *);
static void unp_scan(struct mbuf *, void (*)(file_t *), int);
static void unp_discard_now(file_t *);
static void unp_discard_later(file_t *);
static void unp_thread(void *);
static void unp_thread_kick(void);
static kmutex_t *uipc_lock;
static kcondvar_t unp_thread_cv;
static lwp_t *unp_thread_lwp;
static SLIST_HEAD(,file) unp_thread_discard;
static int unp_defer;
/*
* Initialize Unix protocols.
*/
void
uipc_init(void)
{
int error;
uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
cv_init(&unp_thread_cv, "unpgc");
error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, unp_thread,
NULL, &unp_thread_lwp, "unpgc");
if (error != 0)
panic("uipc_init %d", error);
}
/*
* A connection succeeded: disassociate both endpoints from the head's
* lock, and make them share their own lock. There is a race here: for
* a very brief time one endpoint will be locked by a different lock
* than the other end. However, since the current thread holds the old
* lock (the listening socket's lock, the head) access can still only be
* made to one side of the connection.
*/
static void
unp_setpeerlocks(struct socket *so, struct socket *so2)
{
struct unpcb *unp;
kmutex_t *lock;
KASSERT(solocked2(so, so2));
/*
* Bail out if either end of the socket is not yet fully
* connected or accepted. We only break the lock association
* with the head when the pair of sockets stand completely
* on their own.
*/
KASSERT(so->so_head == NULL);
if (so2->so_head != NULL)
return;
/*
* Drop references to old lock. A third reference (from the
* queue head) must be held as we still hold its lock. Bonus:
* we don't need to worry about garbage collecting the lock.
*/
lock = so->so_lock;
KASSERT(lock == uipc_lock);
mutex_obj_free(lock);
mutex_obj_free(lock);
/*
* Grab stream lock from the initiator and share between the two
* endpoints. Issue memory barrier to ensure all modifications
* become globally visible before the lock change. so2 is
* assumed not to have a stream lock, because it was created
* purely for the server side to accept this connection and
* started out life using the domain-wide lock.
*/
unp = sotounpcb(so);
KASSERT(unp->unp_streamlock != NULL);
KASSERT(sotounpcb(so2)->unp_streamlock == NULL);
lock = unp->unp_streamlock;
unp->unp_streamlock = NULL;
mutex_obj_hold(lock);
membar_exit();
/*
* possible race if lock is not held - see comment in
* uipc_usrreq(PRU_ACCEPT).
*/
KASSERT(mutex_owned(lock));
solockreset(so, lock);
solockreset(so2, lock);
}
/*
* Reset a socket's lock back to the domain-wide lock.
*/
static void
unp_resetlock(struct socket *so)
{
kmutex_t *olock, *nlock;
struct unpcb *unp;
KASSERT(solocked(so));
olock = so->so_lock;
nlock = uipc_lock;
if (olock == nlock)
return;
unp = sotounpcb(so);
KASSERT(unp->unp_streamlock == NULL);
unp->unp_streamlock = olock;
mutex_obj_hold(nlock);
mutex_enter(nlock);
solockreset(so, nlock);
mutex_exit(olock);
}
static void
unp_free(struct unpcb *unp)
{
if (unp->unp_addr)
free(unp->unp_addr, M_SONAME);
if (unp->unp_streamlock != NULL)
mutex_obj_free(unp->unp_streamlock);
free(unp, M_PCB);
}
int
unp_output(struct mbuf *m, struct mbuf *control, struct unpcb *unp,
struct lwp *l)
{
struct socket *so2;
const struct sockaddr_un *sun;
so2 = unp->unp_conn->unp_socket;
KASSERT(solocked(so2));
if (unp->unp_addr)
sun = unp->unp_addr;
else
sun = &sun_noname;
if (unp->unp_conn->unp_flags & UNP_WANTCRED)
control = unp_addsockcred(l, control);
if (sbappendaddr(&so2->so_rcv, (const struct sockaddr *)sun, m,
control) == 0) {
so2->so_rcv.sb_overflowed++;
unp_dispose(control);
m_freem(control);
m_freem(m);
return (ENOBUFS);
} else {
sorwakeup(so2);
return (0);
}
}
void
unp_setaddr(struct socket *so, struct mbuf *nam, bool peeraddr)
{
const struct sockaddr_un *sun;
struct unpcb *unp;
bool ext;
KASSERT(solocked(so));
unp = sotounpcb(so);
ext = false;
for (;;) {
sun = NULL;
if (peeraddr) {
if (unp->unp_conn && unp->unp_conn->unp_addr)
sun = unp->unp_conn->unp_addr;
} else {
if (unp->unp_addr)
sun = unp->unp_addr;
}
if (sun == NULL)
sun = &sun_noname;
nam->m_len = sun->sun_len;
if (nam->m_len > MLEN && !ext) {
sounlock(so);
MEXTMALLOC(nam, MAXPATHLEN * 2, M_WAITOK);
solock(so);
ext = true;
} else {
KASSERT(nam->m_len <= MAXPATHLEN * 2);
memcpy(mtod(nam, void *), sun, (size_t)nam->m_len);
break;
}
}
}
/*ARGSUSED*/
int
uipc_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam,
struct mbuf *control, struct lwp *l)
{
struct unpcb *unp = sotounpcb(so);
struct socket *so2;
struct proc *p;
u_int newhiwat;
int error = 0;
if (req == PRU_CONTROL)
return (EOPNOTSUPP);
#ifdef DIAGNOSTIC
if (req != PRU_SEND && req != PRU_SENDOOB && control)
panic("uipc_usrreq: unexpected control mbuf");
#endif
p = l ? l->l_proc : NULL;
if (req != PRU_ATTACH) {
if (unp == NULL) {
error = EINVAL;
goto release;
}
KASSERT(solocked(so));
}
switch (req) {
case PRU_ATTACH:
if (unp != NULL) {
error = EISCONN;
break;
}
error = unp_attach(so);
break;
case PRU_DETACH:
unp_detach(unp);
break;
case PRU_BIND:
KASSERT(l != NULL);
error = unp_bind(so, nam, l);
break;
case PRU_LISTEN:
/*
* If the socket can accept a connection, it must be
* locked by uipc_lock.
*/
unp_resetlock(so);
if (unp->unp_vnode == NULL)
error = EINVAL;
break;
case PRU_CONNECT:
KASSERT(l != NULL);
error = unp_connect(so, nam, l);
break;
case PRU_CONNECT2:
error = unp_connect2(so, (struct socket *)nam, PRU_CONNECT2);
break;
case PRU_DISCONNECT:
unp_disconnect(unp);
break;
case PRU_ACCEPT:
KASSERT(so->so_lock == uipc_lock);
/*
* Mark the initiating STREAM socket as connected *ONLY*
* after it's been accepted. This prevents a client from
* overrunning a server and receiving ECONNREFUSED.
*/
if (unp->unp_conn == NULL)
break;
so2 = unp->unp_conn->unp_socket;
if (so2->so_state & SS_ISCONNECTING) {
KASSERT(solocked2(so, so->so_head));
KASSERT(solocked2(so2, so->so_head));
soisconnected(so2);
}
/*
* If the connection is fully established, break the
* association with uipc_lock and give the connected
* pair a seperate lock to share.
* There is a race here: sotounpcb(so2)->unp_streamlock
* is not locked, so when changing so2->so_lock
* another thread can grab it while so->so_lock is still
* pointing to the (locked) uipc_lock.
* this should be harmless, except that this makes
* solocked2() and solocked() unreliable.
* Another problem is that unp_setaddr() expects the
* the socket locked. Grabing sotounpcb(so2)->unp_streamlock
* fixes both issues.
*/
mutex_enter(sotounpcb(so2)->unp_streamlock);
unp_setpeerlocks(so2, so);
/*
* Only now return peer's address, as we may need to
* block in order to allocate memory.
*
* XXX Minor race: connection can be broken while
* lock is dropped in unp_setaddr(). We will return
* error == 0 and sun_noname as the peer address.
*/
unp_setaddr(so, nam, true);
/* so_lock now points to unp_streamlock */
mutex_exit(so2->so_lock);
break;
case PRU_SHUTDOWN:
socantsendmore(so);
unp_shutdown(unp);
break;
case PRU_RCVD:
switch (so->so_type) {
case SOCK_DGRAM:
panic("uipc 1");
/*NOTREACHED*/
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
#define rcv (&so->so_rcv)
#define snd (&so2->so_snd)
if (unp->unp_conn == 0)
break;
so2 = unp->unp_conn->unp_socket;
KASSERT(solocked2(so, so2));
/*
* Adjust backpressure on sender
* and wakeup any waiting to write.
*/
snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt;
unp->unp_mbcnt = rcv->sb_mbcnt;
newhiwat = snd->sb_hiwat + unp->unp_cc - rcv->sb_cc;
(void)chgsbsize(so2->so_uidinfo,
&snd->sb_hiwat, newhiwat, RLIM_INFINITY);
unp->unp_cc = rcv->sb_cc;
sowwakeup(so2);
#undef snd
#undef rcv
break;
default:
panic("uipc 2");
}
break;
case PRU_SEND:
/*
* Note: unp_internalize() rejects any control message
* other than SCM_RIGHTS, and only allows one. This
* has the side-effect of preventing a caller from
* forging SCM_CREDS.
*/
if (control) {
sounlock(so);
error = unp_internalize(&control);
solock(so);
if (error != 0) {
m_freem(control);
m_freem(m);
break;
}
}
switch (so->so_type) {
case SOCK_DGRAM: {
KASSERT(so->so_lock == uipc_lock);
if (nam) {
if ((so->so_state & SS_ISCONNECTED) != 0)
error = EISCONN;
else {
/*
* Note: once connected, the
* socket's lock must not be
* dropped until we have sent
* the message and disconnected.
* This is necessary to prevent
* intervening control ops, like
* another connection.
*/
error = unp_connect(so, nam, l);
}
} else {
if ((so->so_state & SS_ISCONNECTED) == 0)
error = ENOTCONN;
}
if (error) {
unp_dispose(control);
m_freem(control);
m_freem(m);
break;
}
KASSERT(p != NULL);
error = unp_output(m, control, unp, l);
if (nam)
unp_disconnect(unp);
break;
}
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
#define rcv (&so2->so_rcv)
#define snd (&so->so_snd)
if (unp->unp_conn == NULL) {
error = ENOTCONN;
break;
}
so2 = unp->unp_conn->unp_socket;
KASSERT(solocked2(so, so2));
if (unp->unp_conn->unp_flags & UNP_WANTCRED) {
/*
* Credentials are passed only once on
* SOCK_STREAM and SOCK_SEQPACKET.
*/
unp->unp_conn->unp_flags &= ~UNP_WANTCRED;
control = unp_addsockcred(l, control);
}
/*
* Send to paired receive port, and then reduce
* send buffer hiwater marks to maintain backpressure.
* Wake up readers.
*/
if (control) {
if (sbappendcontrol(rcv, m, control) != 0)
control = NULL;
} else {
switch(so->so_type) {
case SOCK_SEQPACKET:
sbappendrecord(rcv, m);
break;
case SOCK_STREAM:
sbappend(rcv, m);
break;
default:
panic("uipc_usrreq");
break;
}
}
snd->sb_mbmax -=
rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt;
unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt;
newhiwat = snd->sb_hiwat -
(rcv->sb_cc - unp->unp_conn->unp_cc);
(void)chgsbsize(so->so_uidinfo,
&snd->sb_hiwat, newhiwat, RLIM_INFINITY);
unp->unp_conn->unp_cc = rcv->sb_cc;
sorwakeup(so2);
#undef snd
#undef rcv
if (control != NULL) {
unp_dispose(control);
m_freem(control);
}
break;
default:
panic("uipc 4");
}
break;
case PRU_ABORT:
(void)unp_drop(unp, ECONNABORTED);
KASSERT(so->so_head == NULL);
#ifdef DIAGNOSTIC
if (so->so_pcb == NULL)
panic("uipc 5: drop killed pcb");
#endif
unp_detach(unp);
break;
case PRU_SENSE:
((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat;
switch (so->so_type) {
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
if (unp->unp_conn == 0)
break;
so2 = unp->unp_conn->unp_socket;
KASSERT(solocked2(so, so2));
((struct stat *) m)->st_blksize += so2->so_rcv.sb_cc;
break;
default:
break;
}
((struct stat *) m)->st_dev = NODEV;
if (unp->unp_ino == 0)
unp->unp_ino = unp_ino++;
((struct stat *) m)->st_atimespec =
((struct stat *) m)->st_mtimespec =
((struct stat *) m)->st_ctimespec = unp->unp_ctime;
((struct stat *) m)->st_ino = unp->unp_ino;
return (0);
case PRU_RCVOOB:
error = EOPNOTSUPP;
break;
case PRU_SENDOOB:
m_freem(control);
m_freem(m);
error = EOPNOTSUPP;
break;
case PRU_SOCKADDR:
unp_setaddr(so, nam, false);
break;
case PRU_PEERADDR:
unp_setaddr(so, nam, true);
break;
default:
panic("piusrreq");
}
release:
return (error);
}
/*
* Unix domain socket option processing.
*/
int
uipc_ctloutput(int op, struct socket *so, struct sockopt *sopt)
{
struct unpcb *unp = sotounpcb(so);
int optval = 0, error = 0;
KASSERT(solocked(so));
if (sopt->sopt_level != 0) {
error = ENOPROTOOPT;
} else switch (op) {
case PRCO_SETOPT:
switch (sopt->sopt_name) {
case LOCAL_CREDS:
case LOCAL_CONNWAIT:
error = sockopt_getint(sopt, &optval);
if (error)
break;
switch (sopt->sopt_name) {
#define OPTSET(bit) \
if (optval) \
unp->unp_flags |= (bit); \
else \
unp->unp_flags &= ~(bit);
case LOCAL_CREDS:
OPTSET(UNP_WANTCRED);
break;
case LOCAL_CONNWAIT:
OPTSET(UNP_CONNWAIT);
break;
}
break;
#undef OPTSET
default:
error = ENOPROTOOPT;
break;
}
break;
case PRCO_GETOPT:
sounlock(so);
switch (sopt->sopt_name) {
case LOCAL_PEEREID:
if (unp->unp_flags & UNP_EIDSVALID) {
error = sockopt_set(sopt,
&unp->unp_connid, sizeof(unp->unp_connid));
} else {
error = EINVAL;
}
break;
case LOCAL_CREDS:
#define OPTBIT(bit) (unp->unp_flags & (bit) ? 1 : 0)
optval = OPTBIT(UNP_WANTCRED);
error = sockopt_setint(sopt, optval);
break;
#undef OPTBIT
default:
error = ENOPROTOOPT;
break;
}
solock(so);
break;
}
return (error);
}
/*
* Both send and receive buffers are allocated PIPSIZ bytes of buffering
* for stream sockets, although the total for sender and receiver is
* actually only PIPSIZ.
* Datagram sockets really use the sendspace as the maximum datagram size,
* and don't really want to reserve the sendspace. Their recvspace should
* be large enough for at least one max-size datagram plus address.
*/
#define PIPSIZ 4096
u_long unpst_sendspace = PIPSIZ;
u_long unpst_recvspace = PIPSIZ;
u_long unpdg_sendspace = 2*1024; /* really max datagram size */
u_long unpdg_recvspace = 4*1024;
u_int unp_rights; /* files in flight */
u_int unp_rights_ratio = 2; /* limit, fraction of maxfiles */
int
unp_attach(struct socket *so)
{
struct unpcb *unp;
int error;
switch (so->so_type) {
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
if (so->so_lock == NULL) {
/*
* XXX Assuming that no socket locks are held,
* as this call may sleep.
*/
so->so_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
solock(so);
}
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
error = soreserve(so, unpst_sendspace, unpst_recvspace);
if (error != 0)
return (error);
}
break;
case SOCK_DGRAM:
if (so->so_lock == NULL) {
mutex_obj_hold(uipc_lock);
so->so_lock = uipc_lock;
solock(so);
}
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
error = soreserve(so, unpdg_sendspace, unpdg_recvspace);
if (error != 0)
return (error);
}
break;
default:
panic("unp_attach");
}
KASSERT(solocked(so));
unp = malloc(sizeof(*unp), M_PCB, M_NOWAIT);
if (unp == NULL)
return (ENOBUFS);
memset(unp, 0, sizeof(*unp));
unp->unp_socket = so;
so->so_pcb = unp;
nanotime(&unp->unp_ctime);
return (0);
}
void
unp_detach(struct unpcb *unp)
{
struct socket *so;
vnode_t *vp;
so = unp->unp_socket;
retry:
if ((vp = unp->unp_vnode) != NULL) {
sounlock(so);
/* Acquire v_interlock to protect against unp_connect(). */
/* XXXAD racy */
mutex_enter(vp->v_interlock);
vp->v_socket = NULL;
vrelel(vp, 0);
solock(so);
unp->unp_vnode = NULL;
}
if (unp->unp_conn)
unp_disconnect(unp);
while (unp->unp_refs) {
KASSERT(solocked2(so, unp->unp_refs->unp_socket));
if (unp_drop(unp->unp_refs, ECONNRESET)) {
solock(so);
goto retry;
}
}
soisdisconnected(so);
so->so_pcb = NULL;
if (unp_rights) {
/*
* Normally the receive buffer is flushed later, in sofree,
* but if our receive buffer holds references to files that
* are now garbage, we will enqueue those file references to
* the garbage collector and kick it into action.
*/
sorflush(so);
unp_free(unp);
unp_thread_kick();
} else
unp_free(unp);
}
int
unp_bind(struct socket *so, struct mbuf *nam, struct lwp *l)
{
struct sockaddr_un *sun;
struct unpcb *unp;
vnode_t *vp;
struct vattr vattr;
size_t addrlen;
int error;
struct pathbuf *pb;
struct nameidata nd;
proc_t *p;
unp = sotounpcb(so);
if (unp->unp_vnode != NULL)
return (EINVAL);
if ((unp->unp_flags & UNP_BUSY) != 0) {
/*
* EALREADY may not be strictly accurate, but since this
* is a major application error it's hardly a big deal.
*/
return (EALREADY);
}
unp->unp_flags |= UNP_BUSY;
sounlock(so);
/*
* Allocate the new sockaddr. We have to allocate one
* extra byte so that we can ensure that the pathname
* is nul-terminated.
*/
p = l->l_proc;
addrlen = nam->m_len + 1;
sun = malloc(addrlen, M_SONAME, M_WAITOK);
m_copydata(nam, 0, nam->m_len, (void *)sun);
*(((char *)sun) + nam->m_len) = '\0';
pb = pathbuf_create(sun->sun_path);
if (pb == NULL) {
error = ENOMEM;
goto bad;
}
NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, pb);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
if ((error = namei(&nd)) != 0) {
pathbuf_destroy(pb);
goto bad;
}
vp = nd.ni_vp;
if (vp != NULL) {
VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
if (nd.ni_dvp == vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
vrele(vp);
pathbuf_destroy(pb);
error = EADDRINUSE;
goto bad;
}
vattr_null(&vattr);
vattr.va_type = VSOCK;
vattr.va_mode = ACCESSPERMS & ~(p->p_cwdi->cwdi_cmask);
error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
if (error) {
pathbuf_destroy(pb);
goto bad;
}
vp = nd.ni_vp;
solock(so);
vp->v_socket = unp->unp_socket;
unp->unp_vnode = vp;
unp->unp_addrlen = addrlen;
unp->unp_addr = sun;
unp->unp_connid.unp_pid = p->p_pid;
unp->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred);
unp->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred);
unp->unp_flags |= UNP_EIDSBIND;
VOP_UNLOCK(vp);
unp->unp_flags &= ~UNP_BUSY;
pathbuf_destroy(pb);
return (0);
bad:
free(sun, M_SONAME);
solock(so);
unp->unp_flags &= ~UNP_BUSY;
return (error);
}
int
unp_connect(struct socket *so, struct mbuf *nam, struct lwp *l)
{
struct sockaddr_un *sun;
vnode_t *vp;
struct socket *so2, *so3;
struct unpcb *unp, *unp2, *unp3;
size_t addrlen;
int error;
struct pathbuf *pb;
struct nameidata nd;
unp = sotounpcb(so);
if ((unp->unp_flags & UNP_BUSY) != 0) {
/*
* EALREADY may not be strictly accurate, but since this
* is a major application error it's hardly a big deal.
*/
return (EALREADY);
}
unp->unp_flags |= UNP_BUSY;
sounlock(so);
/*
* Allocate a temporary sockaddr. We have to allocate one extra
* byte so that we can ensure that the pathname is nul-terminated.
* When we establish the connection, we copy the other PCB's
* sockaddr to our own.
*/
addrlen = nam->m_len + 1;
sun = malloc(addrlen, M_SONAME, M_WAITOK);
m_copydata(nam, 0, nam->m_len, (void *)sun);
*(((char *)sun) + nam->m_len) = '\0';
pb = pathbuf_create(sun->sun_path);
if (pb == NULL) {
error = ENOMEM;
goto bad2;
}
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb);
if ((error = namei(&nd)) != 0) {
pathbuf_destroy(pb);
goto bad2;
}
vp = nd.ni_vp;
if (vp->v_type != VSOCK) {
error = ENOTSOCK;
goto bad;
}
pathbuf_destroy(pb);
if ((error = VOP_ACCESS(vp, VWRITE, l->l_cred)) != 0)
goto bad;
/* Acquire v_interlock to protect against unp_detach(). */
mutex_enter(vp->v_interlock);
so2 = vp->v_socket;
if (so2 == NULL) {
mutex_exit(vp->v_interlock);
error = ECONNREFUSED;
goto bad;
}
if (so->so_type != so2->so_type) {
mutex_exit(vp->v_interlock);
error = EPROTOTYPE;
goto bad;
}
solock(so);
unp_resetlock(so);
mutex_exit(vp->v_interlock);
if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) {
/*
* This may seem somewhat fragile but is OK: if we can
* see SO_ACCEPTCONN set on the endpoint, then it must
* be locked by the domain-wide uipc_lock.
*/
KASSERT((so2->so_options & SO_ACCEPTCONN) == 0 ||
so2->so_lock == uipc_lock);
if ((so2->so_options & SO_ACCEPTCONN) == 0 ||
(so3 = sonewconn(so2, 0)) == NULL) {
error = ECONNREFUSED;
sounlock(so);
goto bad;
}
unp2 = sotounpcb(so2);
unp3 = sotounpcb(so3);
if (unp2->unp_addr) {
unp3->unp_addr = malloc(unp2->unp_addrlen,
M_SONAME, M_WAITOK);
memcpy(unp3->unp_addr, unp2->unp_addr,
unp2->unp_addrlen);
unp3->unp_addrlen = unp2->unp_addrlen;
}
unp3->unp_flags = unp2->unp_flags;
unp3->unp_connid.unp_pid = l->l_proc->p_pid;
unp3->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred);
unp3->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred);
unp3->unp_flags |= UNP_EIDSVALID;
if (unp2->unp_flags & UNP_EIDSBIND) {
unp->unp_connid = unp2->unp_connid;
unp->unp_flags |= UNP_EIDSVALID;
}
so2 = so3;
}
error = unp_connect2(so, so2, PRU_CONNECT);
sounlock(so);
bad:
vput(vp);
bad2:
free(sun, M_SONAME);
solock(so);
unp->unp_flags &= ~UNP_BUSY;
return (error);
}
int
unp_connect2(struct socket *so, struct socket *so2, int req)
{
struct unpcb *unp = sotounpcb(so);
struct unpcb *unp2;
if (so2->so_type != so->so_type)
return (EPROTOTYPE);
/*
* All three sockets involved must be locked by same lock:
*
* local endpoint (so)
* remote endpoint (so2)
* queue head (so2->so_head, only if PR_CONNREQUIRED)
*/
KASSERT(solocked2(so, so2));
KASSERT(so->so_head == NULL);
if (so2->so_head != NULL) {
KASSERT(so2->so_lock == uipc_lock);
KASSERT(solocked2(so2, so2->so_head));
}
unp2 = sotounpcb(so2);
unp->unp_conn = unp2;
switch (so->so_type) {
case SOCK_DGRAM:
unp->unp_nextref = unp2->unp_refs;
unp2->unp_refs = unp;
soisconnected(so);
break;
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
unp2->unp_conn = unp;
if (req == PRU_CONNECT &&
((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
soisconnecting(so);
else
soisconnected(so);
soisconnected(so2);
/*
* If the connection is fully established, break the
* association with uipc_lock and give the connected
* pair a seperate lock to share. For CONNECT2, we
* require that the locks already match (the sockets
* are created that way).
*/
if (req == PRU_CONNECT) {
KASSERT(so2->so_head != NULL);
unp_setpeerlocks(so, so2);
}
break;
default:
panic("unp_connect2");
}
return (0);
}
void
unp_disconnect(struct unpcb *unp)
{
struct unpcb *unp2 = unp->unp_conn;
struct socket *so;
if (unp2 == 0)
return;
unp->unp_conn = 0;
so = unp->unp_socket;
switch (so->so_type) {
case SOCK_DGRAM:
if (unp2->unp_refs == unp)
unp2->unp_refs = unp->unp_nextref;
else {
unp2 = unp2->unp_refs;
for (;;) {
KASSERT(solocked2(so, unp2->unp_socket));
if (unp2 == 0)
panic("unp_disconnect");
if (unp2->unp_nextref == unp)
break;
unp2 = unp2->unp_nextref;
}
unp2->unp_nextref = unp->unp_nextref;
}
unp->unp_nextref = 0;
so->so_state &= ~SS_ISCONNECTED;
break;
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
KASSERT(solocked2(so, unp2->unp_socket));
soisdisconnected(so);
unp2->unp_conn = 0;
soisdisconnected(unp2->unp_socket);
break;
}
}
#ifdef notdef
unp_abort(struct unpcb *unp)
{
unp_detach(unp);
}
#endif
void
unp_shutdown(struct unpcb *unp)
{
struct socket *so;
switch(unp->unp_socket->so_type) {
case SOCK_SEQPACKET: /* FALLTHROUGH */
case SOCK_STREAM:
if (unp->unp_conn && (so = unp->unp_conn->unp_socket))
socantrcvmore(so);
break;
default:
break;
}
}
bool
unp_drop(struct unpcb *unp, int errno)
{
struct socket *so = unp->unp_socket;
KASSERT(solocked(so));
so->so_error = errno;
unp_disconnect(unp);
if (so->so_head) {
so->so_pcb = NULL;
/* sofree() drops the socket lock */
sofree(so);
unp_free(unp);
return true;
}
return false;
}
#ifdef notdef
unp_drain(void)
{
}
#endif
int
unp_externalize(struct mbuf *rights, struct lwp *l, int flags)
{
struct cmsghdr * const cm = mtod(rights, struct cmsghdr *);
struct proc * const p = l->l_proc;
file_t **rp;
int error = 0;
const size_t nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) /
sizeof(file_t *);
int * const fdp = kmem_alloc(nfds * sizeof(int), KM_SLEEP);
rw_enter(&p->p_cwdi->cwdi_lock, RW_READER);
/* Make sure the recipient should be able to see the files.. */
rp = (file_t **)CMSG_DATA(cm);
for (size_t i = 0; i < nfds; i++) {
file_t * const fp = *rp++;
if (fp == NULL) {
error = EINVAL;
goto out;
}
/*
* If we are in a chroot'ed directory, and
* someone wants to pass us a directory, make
* sure it's inside the subtree we're allowed
* to access.
*/
if (p->p_cwdi->cwdi_rdir != NULL && fp->f_type == DTYPE_VNODE) {
vnode_t *vp = (vnode_t *)fp->f_data;
if ((vp->v_type == VDIR) &&
!vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) {
error = EPERM;
goto out;
}
}
}
restart:
/*
* First loop -- allocate file descriptor table slots for the
* new files.
*/
for (size_t i = 0; i < nfds; i++) {
if ((error = fd_alloc(p, 0, &fdp[i])) != 0) {
/*
* Back out what we've done so far.
*/
while (i-- > 0) {
fd_abort(p, NULL, fdp[i]);
}
if (error == ENOSPC) {
fd_tryexpand(p);
error = 0;
goto restart;
}
/*
* This is the error that has historically
* been returned, and some callers may
* expect it.
*/
error = EMSGSIZE;
goto out;
}
}
/*
* Now that adding them has succeeded, update all of the
* file passing state and affix the descriptors.
*/
rp = (file_t **)CMSG_DATA(cm);
int *ofdp = (int *)CMSG_DATA(cm);
for (size_t i = 0; i < nfds; i++) {
file_t * const fp = *rp++;
const int fd = fdp[i];
atomic_dec_uint(&unp_rights);
fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0);
fd_affix(p, fp, fd);
/*
* Done with this file pointer, replace it with a fd;
*/
*ofdp++ = fd;
mutex_enter(&fp->f_lock);
fp->f_msgcount--;
mutex_exit(&fp->f_lock);
/*
* Note that fd_affix() adds a reference to the file.
* The file may already have been closed by another
* LWP in the process, so we must drop the reference
* added by unp_internalize() with closef().
*/
closef(fp);
}
/*
* Adjust length, in case of transition from large file_t
* pointers to ints.
*/
if (sizeof(file_t *) != sizeof(int)) {
cm->cmsg_len = CMSG_LEN(nfds * sizeof(int));
rights->m_len = CMSG_SPACE(nfds * sizeof(int));
}
out:
if (__predict_false(error != 0)) {
rp = (file_t **)CMSG_DATA(cm);
for (size_t i = 0; i < nfds; i++) {
file_t * const fp = *rp;
*rp++ = 0;
unp_discard_now(fp);
}
}
rw_exit(&p->p_cwdi->cwdi_lock);
kmem_free(fdp, nfds * sizeof(int));
return error;
}
int
unp_internalize(struct mbuf **controlp)
{
filedesc_t *fdescp = curlwp->l_fd;
struct mbuf *control = *controlp;
struct cmsghdr *newcm, *cm = mtod(control, struct cmsghdr *);
file_t **rp, **files;
file_t *fp;
int i, fd, *fdp;
int nfds, error;
u_int maxmsg;
error = 0;
newcm = NULL;
/* Sanity check the control message header. */
if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
cm->cmsg_len > control->m_len ||
cm->cmsg_len < CMSG_ALIGN(sizeof(*cm)))
return (EINVAL);
/*
* Verify that the file descriptors are valid, and acquire
* a reference to each.
*/
nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / sizeof(int);
fdp = (int *)CMSG_DATA(cm);
maxmsg = maxfiles / unp_rights_ratio;
for (i = 0; i < nfds; i++) {
fd = *fdp++;
if (atomic_inc_uint_nv(&unp_rights) > maxmsg) {
atomic_dec_uint(&unp_rights);
nfds = i;
error = EAGAIN;
goto out;
}
if ((fp = fd_getfile(fd)) == NULL
|| fp->f_type == DTYPE_KQUEUE) {
if (fp)
fd_putfile(fd);
atomic_dec_uint(&unp_rights);
nfds = i;
error = EBADF;
goto out;
}
}
/* Allocate new space and copy header into it. */
newcm = malloc(CMSG_SPACE(nfds * sizeof(file_t *)), M_MBUF, M_WAITOK);
if (newcm == NULL) {
error = E2BIG;
goto out;
}
memcpy(newcm, cm, sizeof(struct cmsghdr));
files = (file_t **)CMSG_DATA(newcm);
/*
* Transform the file descriptors into file_t pointers, in
* reverse order so that if pointers are bigger than ints, the
* int won't get until we're done. No need to lock, as we have
* already validated the descriptors with fd_getfile().
*/
fdp = (int *)CMSG_DATA(cm) + nfds;
rp = files + nfds;
for (i = 0; i < nfds; i++) {
fp = fdescp->fd_dt->dt_ff[*--fdp]->ff_file;
KASSERT(fp != NULL);
mutex_enter(&fp->f_lock);
*--rp = fp;
fp->f_count++;
fp->f_msgcount++;
mutex_exit(&fp->f_lock);
}
out:
/* Release descriptor references. */
fdp = (int *)CMSG_DATA(cm);
for (i = 0; i < nfds; i++) {
fd_putfile(*fdp++);
if (error != 0) {
atomic_dec_uint(&unp_rights);
}
}
if (error == 0) {
if (control->m_flags & M_EXT) {
m_freem(control);
*controlp = control = m_get(M_WAIT, MT_CONTROL);
}
MEXTADD(control, newcm, CMSG_SPACE(nfds * sizeof(file_t *)),
M_MBUF, NULL, NULL);
cm = newcm;
/*
* Adjust message & mbuf to note amount of space
* actually used.
*/
cm->cmsg_len = CMSG_LEN(nfds * sizeof(file_t *));
control->m_len = CMSG_SPACE(nfds * sizeof(file_t *));
}
return error;
}
struct mbuf *
unp_addsockcred(struct lwp *l, struct mbuf *control)
{
struct cmsghdr *cmp;
struct sockcred *sc;
struct mbuf *m, *n;
int len, space, i;
len = CMSG_LEN(SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred)));
space = CMSG_SPACE(SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred)));
m = m_get(M_WAIT, MT_CONTROL);
if (space > MLEN) {
if (space > MCLBYTES)
MEXTMALLOC(m, space, M_WAITOK);
else
m_clget(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
return (control);
}
}
m->m_len = space;
m->m_next = NULL;
cmp = mtod(m, struct cmsghdr *);
sc = (struct sockcred *)CMSG_DATA(cmp);
cmp->cmsg_len = len;
cmp->cmsg_level = SOL_SOCKET;
cmp->cmsg_type = SCM_CREDS;
sc->sc_uid = kauth_cred_getuid(l->l_cred);
sc->sc_euid = kauth_cred_geteuid(l->l_cred);
sc->sc_gid = kauth_cred_getgid(l->l_cred);
sc->sc_egid = kauth_cred_getegid(l->l_cred);
sc->sc_ngroups = kauth_cred_ngroups(l->l_cred);
for (i = 0; i < sc->sc_ngroups; i++)
sc->sc_groups[i] = kauth_cred_group(l->l_cred, i);
/*
* If a control message already exists, append us to the end.
*/
if (control != NULL) {
for (n = control; n->m_next != NULL; n = n->m_next)
;
n->m_next = m;
} else
control = m;
return (control);
}
/*
* Do a mark-sweep GC of files in the system, to free up any which are
* caught in flight to an about-to-be-closed socket. Additionally,
* process deferred file closures.
*/
static void
unp_gc(file_t *dp)
{
extern struct domain unixdomain;
file_t *fp, *np;
struct socket *so, *so1;
u_int i, old, new;
bool didwork;
KASSERT(curlwp == unp_thread_lwp);
KASSERT(mutex_owned(&filelist_lock));
/*
* First, process deferred file closures.
*/
while (!SLIST_EMPTY(&unp_thread_discard)) {
fp = SLIST_FIRST(&unp_thread_discard);
KASSERT(fp->f_unpcount > 0);
KASSERT(fp->f_count > 0);
KASSERT(fp->f_msgcount > 0);
KASSERT(fp->f_count >= fp->f_unpcount);
KASSERT(fp->f_count >= fp->f_msgcount);
KASSERT(fp->f_msgcount >= fp->f_unpcount);
SLIST_REMOVE_HEAD(&unp_thread_discard, f_unplist);
i = fp->f_unpcount;
fp->f_unpcount = 0;
mutex_exit(&filelist_lock);
for (; i != 0; i--) {
unp_discard_now(fp);
}
mutex_enter(&filelist_lock);
}
/*
* Clear mark bits. Ensure that we don't consider new files
* entering the file table during this loop (they will not have
* FSCAN set).
*/
unp_defer = 0;
LIST_FOREACH(fp, &filehead, f_list) {
for (old = fp->f_flag;; old = new) {
new = atomic_cas_uint(&fp->f_flag, old,
(old | FSCAN) & ~(FMARK|FDEFER));
if (__predict_true(old == new)) {
break;
}
}
}
/*
* Iterate over the set of sockets, marking ones believed (based on
* refcount) to be referenced from a process, and marking for rescan
* sockets which are queued on a socket. Recan continues descending
* and searching for sockets referenced by sockets (FDEFER), until
* there are no more socket->socket references to be discovered.
*/
do {
didwork = false;
for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) {
KASSERT(mutex_owned(&filelist_lock));
np = LIST_NEXT(fp, f_list);
mutex_enter(&fp->f_lock);
if ((fp->f_flag & FDEFER) != 0) {
atomic_and_uint(&fp->f_flag, ~FDEFER);
unp_defer--;
KASSERT(fp->f_count != 0);
} else {
if (fp->f_count == 0 ||
(fp->f_flag & FMARK) != 0 ||
fp->f_count == fp->f_msgcount ||
fp->f_unpcount != 0) {
mutex_exit(&fp->f_lock);
continue;
}
}
atomic_or_uint(&fp->f_flag, FMARK);
if (fp->f_type != DTYPE_SOCKET ||
(so = fp->f_data) == NULL ||
so->so_proto->pr_domain != &unixdomain ||
(so->so_proto->pr_flags & PR_RIGHTS) == 0) {
mutex_exit(&fp->f_lock);
continue;
}
/* Gain file ref, mark our position, and unlock. */
didwork = true;
LIST_INSERT_AFTER(fp, dp, f_list);
fp->f_count++;
mutex_exit(&fp->f_lock);
mutex_exit(&filelist_lock);
/*
* Mark files referenced from sockets queued on the
* accept queue as well.
*/
solock(so);
unp_scan(so->so_rcv.sb_mb, unp_mark, 0);
if ((so->so_options & SO_ACCEPTCONN) != 0) {
TAILQ_FOREACH(so1, &so->so_q0, so_qe) {
unp_scan(so1->so_rcv.sb_mb, unp_mark, 0);
}
TAILQ_FOREACH(so1, &so->so_q, so_qe) {
unp_scan(so1->so_rcv.sb_mb, unp_mark, 0);
}
}
sounlock(so);
/* Re-lock and restart from where we left off. */
closef(fp);
mutex_enter(&filelist_lock);
np = LIST_NEXT(dp, f_list);
LIST_REMOVE(dp, f_list);
}
/*
* Bail early if we did nothing in the loop above. Could
* happen because of concurrent activity causing unp_defer
* to get out of sync.
*/
} while (unp_defer != 0 && didwork);
/*
* Sweep pass.
*
* We grab an extra reference to each of the files that are
* not otherwise accessible and then free the rights that are
* stored in messages on them.
*/
for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) {
KASSERT(mutex_owned(&filelist_lock));
np = LIST_NEXT(fp, f_list);
mutex_enter(&fp->f_lock);
/*
* Ignore non-sockets.
* Ignore dead sockets, or sockets with pending close.
* Ignore sockets obviously referenced elsewhere.
* Ignore sockets marked as referenced by our scan.
* Ignore new sockets that did not exist during the scan.
*/
if (fp->f_type != DTYPE_SOCKET ||
fp->f_count == 0 || fp->f_unpcount != 0 ||
fp->f_count != fp->f_msgcount ||
(fp->f_flag & (FMARK | FSCAN)) != FSCAN) {
mutex_exit(&fp->f_lock);
continue;
}
/* Gain file ref, mark our position, and unlock. */
LIST_INSERT_AFTER(fp, dp, f_list);
fp->f_count++;
mutex_exit(&fp->f_lock);
mutex_exit(&filelist_lock);
/*
* Flush all data from the socket's receive buffer.
* This will cause files referenced only by the
* socket to be queued for close.
*/
so = fp->f_data;
solock(so);
sorflush(so);
sounlock(so);
/* Re-lock and restart from where we left off. */
closef(fp);
mutex_enter(&filelist_lock);
np = LIST_NEXT(dp, f_list);
LIST_REMOVE(dp, f_list);
}
}
/*
* Garbage collector thread. While SCM_RIGHTS messages are in transit,
* wake once per second to garbage collect. Run continually while we
* have deferred closes to process.
*/
static void
unp_thread(void *cookie)
{
file_t *dp;
/* Allocate a dummy file for our scans. */
if ((dp = fgetdummy()) == NULL) {
panic("unp_thread");
}
mutex_enter(&filelist_lock);
for (;;) {
KASSERT(mutex_owned(&filelist_lock));
if (SLIST_EMPTY(&unp_thread_discard)) {
if (unp_rights != 0) {
(void)cv_timedwait(&unp_thread_cv,
&filelist_lock, hz);
} else {
cv_wait(&unp_thread_cv, &filelist_lock);
}
}
unp_gc(dp);
}
/* NOTREACHED */
}
/*
* Kick the garbage collector into action if there is something for
* it to process.
*/
static void
unp_thread_kick(void)
{
if (!SLIST_EMPTY(&unp_thread_discard) || unp_rights != 0) {
mutex_enter(&filelist_lock);
cv_signal(&unp_thread_cv);
mutex_exit(&filelist_lock);
}
}
void
unp_dispose(struct mbuf *m)
{
if (m)
unp_scan(m, unp_discard_later, 1);
}
void
unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard)
{
struct mbuf *m;
file_t **rp, *fp;
struct cmsghdr *cm;
int i, qfds;
while (m0) {
for (m = m0; m; m = m->m_next) {
if (m->m_type != MT_CONTROL ||
m->m_len < sizeof(*cm)) {
continue;
}
cm = mtod(m, struct cmsghdr *);
if (cm->cmsg_level != SOL_SOCKET ||
cm->cmsg_type != SCM_RIGHTS)
continue;
qfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm)))
/ sizeof(file_t *);
rp = (file_t **)CMSG_DATA(cm);
for (i = 0; i < qfds; i++) {
fp = *rp;
if (discard) {
*rp = 0;
}
(*op)(fp);
rp++;
}
}
m0 = m0->m_nextpkt;
}
}
void
unp_mark(file_t *fp)
{
if (fp == NULL)
return;
/* If we're already deferred, don't screw up the defer count */
mutex_enter(&fp->f_lock);
if (fp->f_flag & (FMARK | FDEFER)) {
mutex_exit(&fp->f_lock);
return;
}
/*
* Minimize the number of deferrals... Sockets are the only type of
* file which can hold references to another file, so just mark
* other files, and defer unmarked sockets for the next pass.
*/
if (fp->f_type == DTYPE_SOCKET) {
unp_defer++;
KASSERT(fp->f_count != 0);
atomic_or_uint(&fp->f_flag, FDEFER);
} else {
atomic_or_uint(&fp->f_flag, FMARK);
}
mutex_exit(&fp->f_lock);
}
static void
unp_discard_now(file_t *fp)
{
if (fp == NULL)
return;
KASSERT(fp->f_count > 0);
KASSERT(fp->f_msgcount > 0);
mutex_enter(&fp->f_lock);
fp->f_msgcount--;
mutex_exit(&fp->f_lock);
atomic_dec_uint(&unp_rights);
(void)closef(fp);
}
static void
unp_discard_later(file_t *fp)
{
if (fp == NULL)
return;
KASSERT(fp->f_count > 0);
KASSERT(fp->f_msgcount > 0);
mutex_enter(&filelist_lock);
if (fp->f_unpcount++ == 0) {
SLIST_INSERT_HEAD(&unp_thread_discard, fp, f_unplist);
}
mutex_exit(&filelist_lock);
}
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