849 lines
20 KiB
C
849 lines
20 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94
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* $Id: uipc_usrreq.c,v 1.3 1994/08/02 07:43:12 davidg Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/filedesc.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/unpcb.h>
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#include <sys/un.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/mbuf.h>
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void unp_detach __P((struct unpcb *));
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void unp_disconnect __P((struct unpcb *));
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void unp_shutdown __P((struct unpcb *));
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void unp_drop __P((struct unpcb *, int));
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void unp_gc __P((void));
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void unp_scan __P((struct mbuf *, void (*)(struct file *)));
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void unp_mark __P((struct file *));
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void unp_discard __P((struct file *));
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/*
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* Unix communications domain.
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*
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* TODO:
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* SEQPACKET, RDM
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* rethink name space problems
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* need a proper out-of-band
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*/
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struct sockaddr sun_noname = { sizeof(sun_noname), AF_UNIX };
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ino_t unp_ino; /* prototype for fake inode numbers */
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/*ARGSUSED*/
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int
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uipc_usrreq(so, req, m, nam, control)
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struct socket *so;
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int req;
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struct mbuf *m, *nam, *control;
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{
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struct unpcb *unp = sotounpcb(so);
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register struct socket *so2;
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register int error = 0;
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struct proc *p = curproc; /* XXX */
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if (req == PRU_CONTROL)
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return (EOPNOTSUPP);
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if (req != PRU_SEND && control && control->m_len) {
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error = EOPNOTSUPP;
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goto release;
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}
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if (unp == 0 && req != PRU_ATTACH) {
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error = EINVAL;
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goto release;
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}
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switch (req) {
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case PRU_ATTACH:
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if (unp) {
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error = EISCONN;
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break;
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}
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error = unp_attach(so);
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break;
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case PRU_DETACH:
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unp_detach(unp);
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break;
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case PRU_BIND:
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error = unp_bind(unp, nam, p);
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break;
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case PRU_LISTEN:
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if (unp->unp_vnode == 0)
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error = EINVAL;
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break;
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case PRU_CONNECT:
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error = unp_connect(so, nam, p);
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break;
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case PRU_CONNECT2:
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error = unp_connect2(so, (struct socket *)nam);
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break;
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case PRU_DISCONNECT:
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unp_disconnect(unp);
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break;
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case PRU_ACCEPT:
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/*
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* Pass back name of connected socket,
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* if it was bound and we are still connected
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* (our peer may have closed already!).
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*/
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if (unp->unp_conn && unp->unp_conn->unp_addr) {
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nam->m_len = unp->unp_conn->unp_addr->m_len;
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bcopy(mtod(unp->unp_conn->unp_addr, caddr_t),
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mtod(nam, caddr_t), (unsigned)nam->m_len);
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} else {
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nam->m_len = sizeof(sun_noname);
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*(mtod(nam, struct sockaddr *)) = sun_noname;
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}
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break;
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case PRU_SHUTDOWN:
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socantsendmore(so);
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unp_shutdown(unp);
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break;
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case PRU_RCVD:
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switch (so->so_type) {
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case SOCK_DGRAM:
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panic("uipc 1");
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/*NOTREACHED*/
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case SOCK_STREAM:
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#define rcv (&so->so_rcv)
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#define snd (&so2->so_snd)
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if (unp->unp_conn == 0)
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break;
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so2 = unp->unp_conn->unp_socket;
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/*
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* Adjust backpressure on sender
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* and wakeup any waiting to write.
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*/
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snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt;
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unp->unp_mbcnt = rcv->sb_mbcnt;
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snd->sb_hiwat += unp->unp_cc - rcv->sb_cc;
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unp->unp_cc = rcv->sb_cc;
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sowwakeup(so2);
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#undef snd
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#undef rcv
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break;
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default:
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panic("uipc 2");
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}
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break;
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case PRU_SEND:
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if (control && (error = unp_internalize(control, p)))
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break;
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switch (so->so_type) {
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case SOCK_DGRAM: {
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struct sockaddr *from;
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if (nam) {
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if (unp->unp_conn) {
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error = EISCONN;
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break;
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}
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error = unp_connect(so, nam, p);
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if (error)
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break;
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} else {
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if (unp->unp_conn == 0) {
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error = ENOTCONN;
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break;
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}
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}
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so2 = unp->unp_conn->unp_socket;
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if (unp->unp_addr)
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from = mtod(unp->unp_addr, struct sockaddr *);
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else
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from = &sun_noname;
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if (sbappendaddr(&so2->so_rcv, from, m, control)) {
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sorwakeup(so2);
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m = 0;
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control = 0;
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} else
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error = ENOBUFS;
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if (nam)
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unp_disconnect(unp);
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break;
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}
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case SOCK_STREAM:
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#define rcv (&so2->so_rcv)
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#define snd (&so->so_snd)
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if (so->so_state & SS_CANTSENDMORE) {
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error = EPIPE;
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break;
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}
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if (unp->unp_conn == 0)
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panic("uipc 3");
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so2 = unp->unp_conn->unp_socket;
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/*
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* Send to paired receive port, and then reduce
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* send buffer hiwater marks to maintain backpressure.
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* Wake up readers.
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*/
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if (control) {
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if (sbappendcontrol(rcv, m, control))
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control = 0;
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} else
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sbappend(rcv, m);
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snd->sb_mbmax -=
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rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt;
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unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt;
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snd->sb_hiwat -= rcv->sb_cc - unp->unp_conn->unp_cc;
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unp->unp_conn->unp_cc = rcv->sb_cc;
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sorwakeup(so2);
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m = 0;
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#undef snd
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#undef rcv
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break;
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default:
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panic("uipc 4");
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}
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break;
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case PRU_ABORT:
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unp_drop(unp, ECONNABORTED);
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break;
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case PRU_SENSE:
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((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat;
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if (so->so_type == SOCK_STREAM && unp->unp_conn != 0) {
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so2 = unp->unp_conn->unp_socket;
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((struct stat *) m)->st_blksize += so2->so_rcv.sb_cc;
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}
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((struct stat *) m)->st_dev = NODEV;
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if (unp->unp_ino == 0)
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unp->unp_ino = unp_ino++;
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((struct stat *) m)->st_ino = unp->unp_ino;
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return (0);
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case PRU_RCVOOB:
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return (EOPNOTSUPP);
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case PRU_SENDOOB:
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error = EOPNOTSUPP;
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break;
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case PRU_SOCKADDR:
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if (unp->unp_addr) {
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nam->m_len = unp->unp_addr->m_len;
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bcopy(mtod(unp->unp_addr, caddr_t),
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mtod(nam, caddr_t), (unsigned)nam->m_len);
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} else
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nam->m_len = 0;
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break;
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case PRU_PEERADDR:
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if (unp->unp_conn && unp->unp_conn->unp_addr) {
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nam->m_len = unp->unp_conn->unp_addr->m_len;
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bcopy(mtod(unp->unp_conn->unp_addr, caddr_t),
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mtod(nam, caddr_t), (unsigned)nam->m_len);
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} else
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nam->m_len = 0;
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break;
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case PRU_SLOWTIMO:
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break;
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default:
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panic("piusrreq");
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}
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release:
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if (control)
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m_freem(control);
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if (m)
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m_freem(m);
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return (error);
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}
|
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|
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/*
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* Both send and receive buffers are allocated PIPSIZ bytes of buffering
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* for stream sockets, although the total for sender and receiver is
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* actually only PIPSIZ.
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* Datagram sockets really use the sendspace as the maximum datagram size,
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* and don't really want to reserve the sendspace. Their recvspace should
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* be large enough for at least one max-size datagram plus address.
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*/
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#define PIPSIZ 4096
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u_long unpst_sendspace = PIPSIZ;
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u_long unpst_recvspace = PIPSIZ;
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u_long unpdg_sendspace = 2*1024; /* really max datagram size */
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u_long unpdg_recvspace = 4*1024;
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|
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int unp_rights; /* file descriptors in flight */
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|
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int
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unp_attach(so)
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struct socket *so;
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{
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register struct mbuf *m;
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register struct unpcb *unp;
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int error;
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if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
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switch (so->so_type) {
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case SOCK_STREAM:
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error = soreserve(so, unpst_sendspace, unpst_recvspace);
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break;
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case SOCK_DGRAM:
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error = soreserve(so, unpdg_sendspace, unpdg_recvspace);
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break;
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default:
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panic("unp_attach");
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}
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if (error)
|
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return (error);
|
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}
|
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m = m_getclr(M_DONTWAIT, MT_PCB);
|
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if (m == NULL)
|
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return (ENOBUFS);
|
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unp = mtod(m, struct unpcb *);
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so->so_pcb = (caddr_t)unp;
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unp->unp_socket = so;
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return (0);
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}
|
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|
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void
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unp_detach(unp)
|
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register struct unpcb *unp;
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{
|
|
|
|
if (unp->unp_vnode) {
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unp->unp_vnode->v_socket = 0;
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vrele(unp->unp_vnode);
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unp->unp_vnode = 0;
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}
|
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if (unp->unp_conn)
|
|
unp_disconnect(unp);
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while (unp->unp_refs)
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unp_drop(unp->unp_refs, ECONNRESET);
|
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soisdisconnected(unp->unp_socket);
|
|
unp->unp_socket->so_pcb = 0;
|
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m_freem(unp->unp_addr);
|
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(void) m_free(dtom(unp));
|
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if (unp_rights) {
|
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/*
|
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* Normally the receive buffer is flushed later,
|
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* in sofree, but if our receive buffer holds references
|
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* 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(unp->unp_socket);
|
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unp_gc();
|
|
}
|
|
}
|
|
|
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int
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unp_bind(unp, nam, p)
|
|
struct unpcb *unp;
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struct mbuf *nam;
|
|
struct proc *p;
|
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{
|
|
struct sockaddr_un *soun = mtod(nam, struct sockaddr_un *);
|
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register struct vnode *vp;
|
|
struct vattr vattr;
|
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int error;
|
|
struct nameidata nd;
|
|
|
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NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT, UIO_SYSSPACE,
|
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soun->sun_path, p);
|
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if (unp->unp_vnode != NULL)
|
|
return (EINVAL);
|
|
if (nam->m_len == MLEN) {
|
|
if (*(mtod(nam, caddr_t) + nam->m_len - 1) != 0)
|
|
return (EINVAL);
|
|
} else
|
|
*(mtod(nam, caddr_t) + nam->m_len) = 0;
|
|
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
|
|
if (error = namei(&nd))
|
|
return (error);
|
|
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);
|
|
return (EADDRINUSE);
|
|
}
|
|
VATTR_NULL(&vattr);
|
|
vattr.va_type = VSOCK;
|
|
vattr.va_mode = ACCESSPERMS;
|
|
LEASE_CHECK(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
|
|
if (error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr))
|
|
return (error);
|
|
vp = nd.ni_vp;
|
|
vp->v_socket = unp->unp_socket;
|
|
unp->unp_vnode = vp;
|
|
unp->unp_addr = m_copy(nam, 0, (int)M_COPYALL);
|
|
VOP_UNLOCK(vp);
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
unp_connect(so, nam, p)
|
|
struct socket *so;
|
|
struct mbuf *nam;
|
|
struct proc *p;
|
|
{
|
|
register struct sockaddr_un *soun = mtod(nam, struct sockaddr_un *);
|
|
register struct vnode *vp;
|
|
register struct socket *so2, *so3;
|
|
struct unpcb *unp2, *unp3;
|
|
int error;
|
|
struct nameidata nd;
|
|
|
|
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, soun->sun_path, p);
|
|
if (nam->m_data + nam->m_len == &nam->m_dat[MLEN]) { /* XXX */
|
|
if (*(mtod(nam, caddr_t) + nam->m_len - 1) != 0)
|
|
return (EMSGSIZE);
|
|
} else
|
|
*(mtod(nam, caddr_t) + nam->m_len) = 0;
|
|
if (error = namei(&nd))
|
|
return (error);
|
|
vp = nd.ni_vp;
|
|
if (vp->v_type != VSOCK) {
|
|
error = ENOTSOCK;
|
|
goto bad;
|
|
}
|
|
if (error = VOP_ACCESS(vp, VWRITE, p->p_ucred, p))
|
|
goto bad;
|
|
so2 = vp->v_socket;
|
|
if (so2 == 0) {
|
|
error = ECONNREFUSED;
|
|
goto bad;
|
|
}
|
|
if (so->so_type != so2->so_type) {
|
|
error = EPROTOTYPE;
|
|
goto bad;
|
|
}
|
|
if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
|
|
if ((so2->so_options & SO_ACCEPTCONN) == 0 ||
|
|
(so3 = sonewconn(so2, 0)) == 0) {
|
|
error = ECONNREFUSED;
|
|
goto bad;
|
|
}
|
|
unp2 = sotounpcb(so2);
|
|
unp3 = sotounpcb(so3);
|
|
if (unp2->unp_addr)
|
|
unp3->unp_addr =
|
|
m_copy(unp2->unp_addr, 0, (int)M_COPYALL);
|
|
so2 = so3;
|
|
}
|
|
error = unp_connect2(so, so2);
|
|
bad:
|
|
vput(vp);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
unp_connect2(so, so2)
|
|
register struct socket *so;
|
|
register struct socket *so2;
|
|
{
|
|
register struct unpcb *unp = sotounpcb(so);
|
|
register struct unpcb *unp2;
|
|
|
|
if (so2->so_type != so->so_type)
|
|
return (EPROTOTYPE);
|
|
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;
|
|
soisconnected(so);
|
|
soisconnected(so2);
|
|
break;
|
|
|
|
default:
|
|
panic("unp_connect2");
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
unp_disconnect(unp)
|
|
struct unpcb *unp;
|
|
{
|
|
register struct unpcb *unp2 = unp->unp_conn;
|
|
|
|
if (unp2 == 0)
|
|
return;
|
|
unp->unp_conn = 0;
|
|
switch (unp->unp_socket->so_type) {
|
|
|
|
case SOCK_DGRAM:
|
|
if (unp2->unp_refs == unp)
|
|
unp2->unp_refs = unp->unp_nextref;
|
|
else {
|
|
unp2 = unp2->unp_refs;
|
|
for (;;) {
|
|
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;
|
|
unp->unp_socket->so_state &= ~SS_ISCONNECTED;
|
|
break;
|
|
|
|
case SOCK_STREAM:
|
|
soisdisconnected(unp->unp_socket);
|
|
unp2->unp_conn = 0;
|
|
soisdisconnected(unp2->unp_socket);
|
|
break;
|
|
}
|
|
}
|
|
|
|
#ifdef notdef
|
|
void
|
|
unp_abort(unp)
|
|
struct unpcb *unp;
|
|
{
|
|
|
|
unp_detach(unp);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
unp_shutdown(unp)
|
|
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);
|
|
}
|
|
|
|
void
|
|
unp_drop(unp, errno)
|
|
struct unpcb *unp;
|
|
int errno;
|
|
{
|
|
struct socket *so = unp->unp_socket;
|
|
|
|
so->so_error = errno;
|
|
unp_disconnect(unp);
|
|
if (so->so_head) {
|
|
so->so_pcb = (caddr_t) 0;
|
|
m_freem(unp->unp_addr);
|
|
(void) m_free(dtom(unp));
|
|
sofree(so);
|
|
}
|
|
}
|
|
|
|
#ifdef notdef
|
|
void
|
|
unp_drain()
|
|
{
|
|
|
|
}
|
|
#endif
|
|
|
|
int
|
|
unp_externalize(rights)
|
|
struct mbuf *rights;
|
|
{
|
|
struct proc *p = curproc; /* XXX */
|
|
register int i;
|
|
register struct cmsghdr *cm = mtod(rights, struct cmsghdr *);
|
|
register struct file **rp = (struct file **)(cm + 1);
|
|
register struct file *fp;
|
|
int newfds = (cm->cmsg_len - sizeof(*cm)) / sizeof (int);
|
|
int f;
|
|
|
|
if (!fdavail(p, newfds)) {
|
|
for (i = 0; i < newfds; i++) {
|
|
fp = *rp;
|
|
unp_discard(fp);
|
|
*rp++ = 0;
|
|
}
|
|
return (EMSGSIZE);
|
|
}
|
|
for (i = 0; i < newfds; i++) {
|
|
if (fdalloc(p, 0, &f))
|
|
panic("unp_externalize");
|
|
fp = *rp;
|
|
p->p_fd->fd_ofiles[f] = fp;
|
|
fp->f_msgcount--;
|
|
unp_rights--;
|
|
*(int *)rp++ = f;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
unp_internalize(control, p)
|
|
struct mbuf *control;
|
|
struct proc *p;
|
|
{
|
|
struct filedesc *fdp = p->p_fd;
|
|
register struct cmsghdr *cm = mtod(control, struct cmsghdr *);
|
|
register struct file **rp;
|
|
register struct file *fp;
|
|
register int i, fd;
|
|
int oldfds;
|
|
|
|
if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
|
|
cm->cmsg_len != control->m_len)
|
|
return (EINVAL);
|
|
oldfds = (cm->cmsg_len - sizeof (*cm)) / sizeof (int);
|
|
rp = (struct file **)(cm + 1);
|
|
for (i = 0; i < oldfds; i++) {
|
|
fd = *(int *)rp++;
|
|
if ((unsigned)fd >= fdp->fd_nfiles ||
|
|
fdp->fd_ofiles[fd] == NULL)
|
|
return (EBADF);
|
|
}
|
|
rp = (struct file **)(cm + 1);
|
|
for (i = 0; i < oldfds; i++) {
|
|
fp = fdp->fd_ofiles[*(int *)rp];
|
|
*rp++ = fp;
|
|
fp->f_count++;
|
|
fp->f_msgcount++;
|
|
unp_rights++;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int unp_defer, unp_gcing;
|
|
extern struct domain unixdomain;
|
|
|
|
void
|
|
unp_gc()
|
|
{
|
|
register struct file *fp, *nextfp;
|
|
register struct socket *so;
|
|
struct file **extra_ref, **fpp;
|
|
int nunref, i;
|
|
|
|
if (unp_gcing)
|
|
return;
|
|
unp_gcing = 1;
|
|
unp_defer = 0;
|
|
for (fp = filehead; fp; fp = fp->f_filef)
|
|
fp->f_flag &= ~(FMARK|FDEFER);
|
|
do {
|
|
for (fp = filehead; fp; fp = fp->f_filef) {
|
|
if (fp->f_count == 0)
|
|
continue;
|
|
if (fp->f_flag & FDEFER) {
|
|
fp->f_flag &= ~FDEFER;
|
|
unp_defer--;
|
|
} else {
|
|
if (fp->f_flag & FMARK)
|
|
continue;
|
|
if (fp->f_count == fp->f_msgcount)
|
|
continue;
|
|
fp->f_flag |= FMARK;
|
|
}
|
|
if (fp->f_type != DTYPE_SOCKET ||
|
|
(so = (struct socket *)fp->f_data) == 0)
|
|
continue;
|
|
if (so->so_proto->pr_domain != &unixdomain ||
|
|
(so->so_proto->pr_flags&PR_RIGHTS) == 0)
|
|
continue;
|
|
#ifdef notdef
|
|
if (so->so_rcv.sb_flags & SB_LOCK) {
|
|
/*
|
|
* 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
|
|
unp_scan(so->so_rcv.sb_mb, unp_mark);
|
|
}
|
|
} while (unp_defer);
|
|
/*
|
|
* 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 orginal 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, we call sorflush ourself, since we know
|
|
* it is a Unix domain socket anyhow. 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
|
|
*/
|
|
extra_ref = malloc(nfiles * sizeof(struct file *), M_FILE, M_WAITOK);
|
|
for (nunref = 0, fp = filehead, fpp = extra_ref; fp; fp = nextfp) {
|
|
nextfp = fp->f_filef;
|
|
if (fp->f_count == 0)
|
|
continue;
|
|
if (fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) {
|
|
*fpp++ = fp;
|
|
nunref++;
|
|
fp->f_count++;
|
|
}
|
|
}
|
|
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp)
|
|
sorflush((struct socket *)(*fpp)->f_data);
|
|
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp)
|
|
closef(*fpp,(struct proc*) NULL);
|
|
free((caddr_t)extra_ref, M_FILE);
|
|
unp_gcing = 0;
|
|
}
|
|
|
|
void
|
|
unp_dispose(m)
|
|
struct mbuf *m;
|
|
{
|
|
if (m)
|
|
unp_scan(m, unp_discard);
|
|
}
|
|
|
|
void
|
|
unp_scan(m0, op)
|
|
register struct mbuf *m0;
|
|
void (*op)(struct file *);
|
|
{
|
|
register struct mbuf *m;
|
|
register struct file **rp;
|
|
register struct cmsghdr *cm;
|
|
register 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 - sizeof *cm)
|
|
/ sizeof (struct file *);
|
|
rp = (struct file **)(cm + 1);
|
|
for (i = 0; i < qfds; i++)
|
|
(*op)(*rp++);
|
|
break; /* XXX, but saves time */
|
|
}
|
|
m0 = m0->m_act;
|
|
}
|
|
}
|
|
|
|
void
|
|
unp_mark(fp)
|
|
struct file *fp;
|
|
{
|
|
|
|
if (fp->f_flag & FMARK)
|
|
return;
|
|
unp_defer++;
|
|
fp->f_flag |= (FMARK|FDEFER);
|
|
}
|
|
|
|
void
|
|
unp_discard(fp)
|
|
struct file *fp;
|
|
{
|
|
|
|
fp->f_msgcount--;
|
|
unp_rights--;
|
|
(void) closef(fp, (struct proc *)NULL);
|
|
}
|