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/* $NetBSD: uipc_usrreq.c,v 1.119 2008/10/11 13:40:57 pooka Exp $ */
/*-
* Copyright (c) 1998, 2000, 2004, 2008 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.
*
* 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 1.119 2008/10/11 13:40:57 pooka 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>
/*
* Unix communications domain.
*
* TODO:
* SEQPACKET, 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 kmutex_t *uipc_lock;
/*
* Initialize Unix protocols.
*/
void
uipc_init(void)
{
uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
}
/*
* 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.
*/
if (so->so_head != NULL || 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();
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++;
sounlock(so2);
unp_dispose(control);
m_freem(control);
m_freem(m);
solock(so2);
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;
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 == 0) {
error = EINVAL;
goto release;
}
KASSERT(solocked(so));
}
switch (req) {
case PRU_ATTACH:
if (unp != 0) {
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 == 0)
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.
*/
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);
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_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) {
sounlock(so);
unp_dispose(control);
m_freem(control);
m_freem(m);
solock(so);
break;
}
KASSERT(p != NULL);
error = unp_output(m, control, unp, l);
if (nam)
unp_disconnect(unp);
break;
}
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.
*/
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
sbappend(rcv, m);
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) {
sounlock(so);
unp_dispose(control);
m_freem(control);
solock(so);
}
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 == 0)
panic("uipc 5: drop killed pcb");
#endif
unp_detach(unp);
break;
case PRU_SENSE:
((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat;
if (so->so_type == SOCK_STREAM && unp->unp_conn != 0) {
so2 = unp->unp_conn->unp_socket;
KASSERT(solocked2(so, so2));
((struct stat *) m)->st_blksize += so2->so_rcv.sb_cc;
}
((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; /* file descriptors in flight */
int
unp_attach(struct socket *so)
{
struct unpcb *unp;
int error;
switch (so->so_type) {
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((void *)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 descriptors that are now garbage, we will dispose
* of those descriptor references after the garbage collector
* gets them (resulting in a "panic: closef: count < 0").
*/
sorflush(so);
unp_free(unp);
sounlock(so);
unp_gc();
solock(so);
} 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 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';
NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, UIO_SYSSPACE,
sun->sun_path);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
if ((error = namei(&nd)) != 0)
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);
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)
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, 0);
unp->unp_flags &= ~UNP_BUSY;
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 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';
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, UIO_SYSSPACE,
sun->sun_path);
if ((error = namei(&nd)) != 0)
goto bad2;
vp = nd.ni_vp;
if (vp->v_type != VSOCK) {
error = ENOTSOCK;
goto bad;
}
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((so->so_options & SO_ACCEPTCONN) == 0 ||
so2->so_lock == uipc_lock);
if ((so2->so_options & SO_ACCEPTCONN) == 0 ||
(so3 = sonewconn(so2, 0)) == 0) {
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 (so->so_head, only if PR_CONNREQUIRED)
*/
KASSERT(solocked2(so, so2));
if (so->so_head != NULL) {
KASSERT(so->so_lock == uipc_lock);
KASSERT(solocked2(so, so->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_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)
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_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;
if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn &&
(so = unp->unp_conn->unp_socket))
socantrcvmore(so);
}
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)
{
struct cmsghdr *cm = mtod(rights, struct cmsghdr *);
struct proc *p = l->l_proc;
int i, *fdp;
file_t **rp;
file_t *fp;
int nfds, error = 0;
nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) /
sizeof(file_t *);
rp = (file_t **)CMSG_DATA(cm);
fdp = malloc(nfds * sizeof(int), M_TEMP, M_WAITOK);
rw_enter(&p->p_cwdi->cwdi_lock, RW_READER);
/* Make sure the recipient should be able to see the descriptors.. */
if (p->p_cwdi->cwdi_rdir != NULL) {
rp = (file_t **)CMSG_DATA(cm);
for (i = 0; i < nfds; i++) {
fp = *rp++;
/*
* 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 (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;
break;
}
}
}
}
restart:
rp = (file_t **)CMSG_DATA(cm);
if (error != 0) {
for (i = 0; i < nfds; i++) {
fp = *rp;
/*
* zero the pointer before calling unp_discard,
* since it may end up in unp_gc()..
*/
*rp++ = 0;
unp_discard(fp);
}
goto out;
}
/*
* First loop -- allocate file descriptor table slots for the
* new descriptors.
*/
for (i = 0; i < nfds; i++) {
fp = *rp++;
if ((error = fd_alloc(p, 0, &fdp[i])) != 0) {
/*
* Back out what we've done so far.
*/
for (--i; i >= 0; i--) {
fd_abort(p, NULL, fdp[i]);
}
if (error == ENOSPC) {
fd_tryexpand(p);
error = 0;
} else {
/*
* This is the error that has historically
* been returned, and some callers may
* expect it.
*/
error = EMSGSIZE;
}
goto restart;
}
}
/*
* Now that adding them has succeeded, update all of the
* descriptor passing state.
*/
rp = (file_t **)CMSG_DATA(cm);
for (i = 0; i < nfds; i++) {
fp = *rp++;
atomic_dec_uint(&unp_rights);
fd_affix(p, fp, fdp[i]);
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);
}
/*
* Copy temporary array to message and adjust length, in case of
* transition from large file_t pointers to ints.
*/
memcpy(CMSG_DATA(cm), fdp, nfds * sizeof(int));
cm->cmsg_len = CMSG_LEN(nfds * sizeof(int));
rights->m_len = CMSG_SPACE(nfds * sizeof(int));
out:
rw_exit(&p->p_cwdi->cwdi_lock);
free(fdp, M_TEMP);
return (error);
}
int
unp_internalize(struct mbuf **controlp)
{
struct filedesc *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;
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);
for (i = 0; i < nfds; i++) {
fd = *fdp++;
if ((fp = fd_getfile(fd)) == NULL) {
nfds = i + 1;
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_ofiles[*--fdp]->ff_file;
KASSERT(fp != NULL);
mutex_enter(&fp->f_lock);
*--rp = fp;
fp->f_count++;
fp->f_msgcount++;
mutex_exit(&fp->f_lock);
atomic_inc_uint(&unp_rights);
}
out:
/* Release descriptor references. */
fdp = (int *)CMSG_DATA(cm);
for (i = 0; i < nfds; i++) {
fd_putfile(*fdp++);
}
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);
}
int unp_defer, unp_gcing;
extern struct domain unixdomain;
/*
* Comment added long after the fact explaining what's going on here.
* Do a mark-sweep GC of file descriptors on the system, to free up
* any which are caught in flight to an about-to-be-closed socket.
*
* Traditional mark-sweep gc's start at the "root", and mark
* everything reachable from the root (which, in our case would be the
* process table). The mark bits are cleared during the sweep.
*
* XXX For some inexplicable reason (perhaps because the file
* descriptor tables used to live in the u area which could be swapped
* out and thus hard to reach), we do multiple scans over the set of
* descriptors, using use *two* mark bits per object (DEFER and MARK).
* Whenever we find a descriptor which references other descriptors,
* the ones it references are marked with both bits, and we iterate
* over the whole file table until there are no more DEFER bits set.
* We also make an extra pass *before* the GC to clear the mark bits,
* which could have been cleared at almost no cost during the previous
* sweep.
*/
void
unp_gc(void)
{
file_t *fp, *nextfp;
struct socket *so, *so1;
file_t **extra_ref, **fpp;
int nunref, nslots, i;
if (atomic_swap_uint(&unp_gcing, 1) == 1)
return;
restart:
nslots = nfiles * 2;
extra_ref = kmem_alloc(nslots * sizeof(file_t *), KM_SLEEP);
mutex_enter(&filelist_lock);
unp_defer = 0;
/* Clear mark bits */
LIST_FOREACH(fp, &filehead, f_list) {
atomic_and_uint(&fp->f_flag, ~(FMARK|FDEFER));
}
/*
* Iterate over the set of descriptors, marking ones believed
* (based on refcount) to be referenced from a process, and
* marking for rescan descriptors which are queued on a socket.
*/
do {
LIST_FOREACH(fp, &filehead, f_list) {
mutex_enter(&fp->f_lock);
if (fp->f_flag & FDEFER) {
atomic_and_uint(&fp->f_flag, ~FDEFER);
unp_defer--;
KASSERT(fp->f_count != 0);
} else {
if (fp->f_count == 0 ||
(fp->f_flag & FMARK) ||
fp->f_count == fp->f_msgcount) {
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;
}
#ifdef notdef
if (so->so_rcv.sb_flags & SB_LOCK) {
mutex_exit(&fp->f_lock);
mutex_exit(&filelist_lock);
kmem_free(extra_ref, nslots * sizeof(file_t *));
/*
* This is problematical; it's not clear
* we need to wait for the sockbuf to be
* unlocked (on a uniprocessor, at least),
* and it's also not clear what to do
* if sbwait returns an error due to receipt
* of a signal. If sbwait does return
* an error, we'll go into an infinite
* loop. Delete all of this for now.
*/
(void) sbwait(&so->so_rcv);
goto restart;
}
#endif
mutex_exit(&fp->f_lock);
/*
* XXX Locking a socket with filelist_lock held
* is ugly. filelist_lock can be taken by the
* pagedaemon when reclaiming items from file_cache.
* Socket activity could delay the pagedaemon.
*/
solock(so);
unp_scan(so->so_rcv.sb_mb, unp_mark, 0);
/*
* Mark descriptors referenced from sockets queued
* on the accept queue as well.
*/
if (so->so_options & SO_ACCEPTCONN) {
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);
}
} while (unp_defer);
/*
* Sweep pass. Find unmarked descriptors, and free them.
*
* We grab an extra reference to each of the file table entries
* that are not otherwise accessible and then free the rights
* that are stored in messages on them.
*
* The bug in the original code is a little tricky, so I'll describe
* what's wrong with it here.
*
* It is incorrect to simply unp_discard each entry for f_msgcount
* times -- consider the case of sockets A and B that contain
* references to each other. On a last close of some other socket,
* we trigger a gc since the number of outstanding rights (unp_rights)
* is non-zero. If during the sweep phase the gc code un_discards,
* we end up doing a (full) closef on the descriptor. A closef on A
* results in the following chain. Closef calls soo_close, which
* calls soclose. Soclose calls first (through the switch
* uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply
* returns because the previous instance had set unp_gcing, and
* we return all the way back to soclose, which marks the socket
* with SS_NOFDREF, and then calls sofree. Sofree calls sorflush
* to free up the rights that are queued in messages on the socket A,
* i.e., the reference on B. The sorflush calls via the dom_dispose
* switch unp_dispose, which unp_scans with unp_discard. This second
* instance of unp_discard just calls closef on B.
*
* Well, a similar chain occurs on B, resulting in a sorflush on B,
* which results in another closef on A. Unfortunately, A is already
* being closed, and the descriptor has already been marked with
* SS_NOFDREF, and soclose panics at this point.
*
* Here, we first take an extra reference to each inaccessible
* descriptor. Then, if the inaccessible descriptor is a
* socket, we call sorflush in case it is a Unix domain
* socket. After we destroy all the rights carried in
* messages, we do a last closef to get rid of our extra
* reference. This is the last close, and the unp_detach etc
* will shut down the socket.
*
* 91/09/19, bsy@cs.cmu.edu
*/
if (nslots < nfiles) {
mutex_exit(&filelist_lock);
kmem_free(extra_ref, nslots * sizeof(file_t *));
goto restart;
}
for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; fp != 0;
fp = nextfp) {
nextfp = LIST_NEXT(fp, f_list);
mutex_enter(&fp->f_lock);
if (fp->f_count != 0 &&
fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) {
*fpp++ = fp;
nunref++;
fp->f_count++;
}
mutex_exit(&fp->f_lock);
}
mutex_exit(&filelist_lock);
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
fp = *fpp;
if (fp->f_type == DTYPE_SOCKET) {
so = fp->f_data;
solock(so);
sorflush(fp->f_data);
sounlock(so);
}
}
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
closef(*fpp);
}
kmem_free(extra_ref, nslots * sizeof(file_t *));
atomic_swap_uint(&unp_gcing, 0);
}
void
unp_dispose(struct mbuf *m)
{
if (m)
unp_scan(m, unp_discard, 1);
}
void
unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard)
{
struct mbuf *m;
file_t **rp;
struct cmsghdr *cm;
int i;
int qfds;
while (m0) {
for (m = m0; m; m = m->m_next) {
if (m->m_type == MT_CONTROL &&
m->m_len >= sizeof(*cm)) {
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++) {
file_t *fp = *rp;
if (discard)
*rp = 0;
(*op)(fp);
rp++;
}
break; /* XXX, but saves time */
}
}
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 descriptor which can hold references to another
* descriptor, so just mark other descriptors, 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);
return;
}
void
unp_discard(file_t *fp)
{
if (fp == NULL)
return;
mutex_enter(&fp->f_lock);
KASSERT(fp->f_count > 0);
fp->f_msgcount--;
mutex_exit(&fp->f_lock);
atomic_dec_uint(&unp_rights);
(void)closef(fp);
}
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