Remove bogus checks after kmalloc(M_WAITOK) which never returns NULL.

[dragonfly.git] / sys / kern / uipc_usrreq.c

/*
 * 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. 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.
 *
 *      From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94
 * $FreeBSD: src/sys/kern/uipc_usrreq.c,v 1.54.2.10 2003/03/04 17:28:09 nectar Exp $
 * $DragonFly: src/sys/kern/uipc_usrreq.c,v 1.37 2008/01/06 16:55:51 swildner Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/domain.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>         /* XXX must be before <sys/file.h> */
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/mbuf.h>
#include <sys/nlookup.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/resourcevar.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <sys/vnode.h>
#include <sys/file2.h>
#include <sys/spinlock2.h>

#include <vm/vm_zone.h>

static  struct vm_zone *unp_zone;
static  unp_gen_t unp_gencnt;
static  u_int unp_count;

static  struct unp_head unp_shead, unp_dhead;

/*
 * Unix communications domain.
 *
 * TODO:
 *      SEQPACKET, RDM
 *      rethink name space problems
 *      need a proper out-of-band
 *      lock pushdown
 */
static struct   sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL };
static ino_t    unp_ino;                /* prototype for fake inode numbers */

static int     unp_attach (struct socket *, struct pru_attach_info *);
static void    unp_detach (struct unpcb *);
static int     unp_bind (struct unpcb *,struct sockaddr *, struct thread *);
static int     unp_connect (struct socket *,struct sockaddr *,
                                struct thread *);
static void    unp_disconnect (struct unpcb *);
static void    unp_shutdown (struct unpcb *);
static void    unp_drop (struct unpcb *, int);
static void    unp_gc (void);
static int     unp_gc_clearmarks(struct file *, void *);
static int     unp_gc_checkmarks(struct file *, void *);
static int     unp_gc_checkrefs(struct file *, void *);
static void    unp_scan (struct mbuf *, void (*)(struct file *, void *),
                                void *data);
static void    unp_mark (struct file *, void *data);
static void    unp_discard (struct file *, void *);
static int     unp_internalize (struct mbuf *, struct thread *);
static int     unp_listen (struct unpcb *, struct thread *);

static int
uipc_abort(struct socket *so)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        unp_drop(unp, ECONNABORTED);
        unp_detach(unp);
        sofree(so);
        return 0;
}

static int
uipc_accept(struct socket *so, struct sockaddr **nam)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;

        /*
         * Pass back name of connected socket,
         * if it was bound and we are still connected
         * (our peer may have closed already!).
         */
        if (unp->unp_conn && unp->unp_conn->unp_addr) {
                *nam = dup_sockaddr((struct sockaddr *)unp->unp_conn->unp_addr);
        } else {
                *nam = dup_sockaddr((struct sockaddr *)&sun_noname);
        }
        return 0;
}

static int
uipc_attach(struct socket *so, int proto, struct pru_attach_info *ai)
{
        struct unpcb *unp = so->so_pcb;

        if (unp != NULL)
                return EISCONN;
        return unp_attach(so, ai);
}

static int
uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        return unp_bind(unp, nam, td);
}

static int
uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        return unp_connect(so, nam, td);
}

static int
uipc_connect2(struct socket *so1, struct socket *so2)
{
        struct unpcb *unp = so1->so_pcb;

        if (unp == NULL)
                return EINVAL;

        return unp_connect2(so1, so2);
}

/* control is EOPNOTSUPP */

static int
uipc_detach(struct socket *so)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;

        unp_detach(unp);
        return 0;
}

static int
uipc_disconnect(struct socket *so)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        unp_disconnect(unp);
        return 0;
}

static int
uipc_listen(struct socket *so, struct thread *td)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL || unp->unp_vnode == NULL)
                return EINVAL;
        return unp_listen(unp, td);
}

static int
uipc_peeraddr(struct socket *so, struct sockaddr **nam)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        if (unp->unp_conn && unp->unp_conn->unp_addr)
                *nam = dup_sockaddr((struct sockaddr *)unp->unp_conn->unp_addr);
        else {
                /*
                 * XXX: It seems that this test always fails even when
                 * connection is established.  So, this else clause is
                 * added as workaround to return PF_LOCAL sockaddr.
                 */
                *nam = dup_sockaddr((struct sockaddr *)&sun_noname);
        }
        return 0;
}

static int
uipc_rcvd(struct socket *so, int flags)
{
        struct unpcb *unp = so->so_pcb;
        struct socket *so2;
        u_long newhiwat;

        if (unp == NULL)
                return EINVAL;
        switch (so->so_type) {
        case SOCK_DGRAM:
                panic("uipc_rcvd DGRAM?");
                /*NOTREACHED*/

        case SOCK_STREAM:
                if (unp->unp_conn == NULL)
                        break;
                so2 = unp->unp_conn->unp_socket;
                /*
                 * Adjust backpressure on sender
                 * and wakeup any waiting to write.
                 */
                so2->so_snd.ssb_mbmax += unp->unp_mbcnt - so->so_rcv.ssb_mbcnt;
                unp->unp_mbcnt = so->so_rcv.ssb_mbcnt;
                newhiwat =
                    so2->so_snd.ssb_hiwat + unp->unp_cc - so->so_rcv.ssb_cc;
                chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.ssb_hiwat,
                    newhiwat, RLIM_INFINITY);
                unp->unp_cc = so->so_rcv.ssb_cc;
                sowwakeup(so2);
                break;

        default:
                panic("uipc_rcvd unknown socktype");
        }
        return 0;
}

/* pru_rcvoob is EOPNOTSUPP */

static int
uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
          struct mbuf *control, struct thread *td)
{
        int error = 0;
        struct unpcb *unp = so->so_pcb;
        struct socket *so2;
        u_long newhiwat;

        if (unp == NULL) {
                error = EINVAL;
                goto release;
        }
        if (flags & PRUS_OOB) {
                error = EOPNOTSUPP;
                goto release;
        }

        if (control && (error = unp_internalize(control, td)))
                goto release;

        switch (so->so_type) {
        case SOCK_DGRAM: 
        {
                struct sockaddr *from;

                if (nam) {
                        if (unp->unp_conn) {
                                error = EISCONN;
                                break;
                        }
                        error = unp_connect(so, nam, td);
                        if (error)
                                break;
                } else {
                        if (unp->unp_conn == NULL) {
                                error = ENOTCONN;
                                break;
                        }
                }
                so2 = unp->unp_conn->unp_socket;
                if (unp->unp_addr)
                        from = (struct sockaddr *)unp->unp_addr;
                else
                        from = &sun_noname;
                if (ssb_appendaddr(&so2->so_rcv, from, m, control)) {
                        sorwakeup(so2);
                        m = NULL;
                        control = NULL;
                } else {
                        error = ENOBUFS;
                }
                if (nam)
                        unp_disconnect(unp);
                break;
        }

        case SOCK_STREAM:
                /* Connect if not connected yet. */
                /*
                 * Note: A better implementation would complain
                 * if not equal to the peer's address.
                 */
                if (!(so->so_state & SS_ISCONNECTED)) {
                        if (nam) {
                                error = unp_connect(so, nam, td);
                                if (error)
                                        break;  /* XXX */
                        } else {
                                error = ENOTCONN;
                                break;
                        }
                }

                if (so->so_state & SS_CANTSENDMORE) {
                        error = EPIPE;
                        break;
                }
                if (unp->unp_conn == NULL)
                        panic("uipc_send connected but no connection?");
                so2 = unp->unp_conn->unp_socket;
                /*
                 * Send to paired receive port, and then reduce
                 * send buffer hiwater marks to maintain backpressure.
                 * Wake up readers.
                 */
                if (control) {
                        if (ssb_appendcontrol(&so2->so_rcv, m, control)) {
                                control = NULL;
                                m = NULL;
                        }
                } else {
                        sbappend(&so2->so_rcv.sb, m);
                        m = NULL;
                }
                so->so_snd.ssb_mbmax -=
                        so2->so_rcv.ssb_mbcnt - unp->unp_conn->unp_mbcnt;
                unp->unp_conn->unp_mbcnt = so2->so_rcv.ssb_mbcnt;
                newhiwat = so->so_snd.ssb_hiwat -
                    (so2->so_rcv.ssb_cc - unp->unp_conn->unp_cc);
                chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.ssb_hiwat,
                    newhiwat, RLIM_INFINITY);
                unp->unp_conn->unp_cc = so2->so_rcv.ssb_cc;
                sorwakeup(so2);
                break;

        default:
                panic("uipc_send unknown socktype");
        }

        /*
         * SEND_EOF is equivalent to a SEND followed by a SHUTDOWN.
         */
        if (flags & PRUS_EOF) {
                socantsendmore(so);
                unp_shutdown(unp);
        }

        if (control && error != 0)
                unp_dispose(control);

release:
        if (control)
                m_freem(control);
        if (m)
                m_freem(m);
        return error;
}

static int
uipc_sense(struct socket *so, struct stat *sb)
{
        struct unpcb *unp = so->so_pcb;
        struct socket *so2;

        if (unp == NULL)
                return EINVAL;
        sb->st_blksize = so->so_snd.ssb_hiwat;
        if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) {
                so2 = unp->unp_conn->unp_socket;
                sb->st_blksize += so2->so_rcv.ssb_cc;
        }
        sb->st_dev = NOUDEV;
        if (unp->unp_ino == 0)          /* make up a non-zero inode number */
                unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
        sb->st_ino = unp->unp_ino;
        return (0);
}

static int
uipc_shutdown(struct socket *so)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        socantsendmore(so);
        unp_shutdown(unp);
        return 0;
}

static int
uipc_sockaddr(struct socket *so, struct sockaddr **nam)
{
        struct unpcb *unp = so->so_pcb;

        if (unp == NULL)
                return EINVAL;
        if (unp->unp_addr)
                *nam = dup_sockaddr((struct sockaddr *)unp->unp_addr);
        return 0;
}

struct pr_usrreqs uipc_usrreqs = {
        .pru_abort = uipc_abort,
        .pru_accept = uipc_accept,
        .pru_attach = uipc_attach,
        .pru_bind = uipc_bind,
        .pru_connect = uipc_connect,
        .pru_connect2 = uipc_connect2,
        .pru_control = pru_control_notsupp,
        .pru_detach = uipc_detach,
        .pru_disconnect = uipc_disconnect,
        .pru_listen = uipc_listen,
        .pru_peeraddr = uipc_peeraddr,
        .pru_rcvd = uipc_rcvd,
        .pru_rcvoob = pru_rcvoob_notsupp,
        .pru_send = uipc_send,
        .pru_sense = uipc_sense,
        .pru_shutdown = uipc_shutdown,
        .pru_sockaddr = uipc_sockaddr,
        .pru_sosend = sosend,
        .pru_soreceive = soreceive,
        .pru_sopoll = sopoll
};

int
uipc_ctloutput(struct socket *so, struct sockopt *sopt)
{
        struct unpcb *unp = so->so_pcb;
        int error;

        switch (sopt->sopt_dir) {
        case SOPT_GET:
                switch (sopt->sopt_name) {
                case LOCAL_PEERCRED:
                        if (unp->unp_flags & UNP_HAVEPC)
                                error = sooptcopyout(sopt, &unp->unp_peercred,
                                    sizeof(unp->unp_peercred));
                        else {
                                if (so->so_type == SOCK_STREAM)
                                        error = ENOTCONN;
                                else
                                        error = EINVAL;
                        }
                        break;
                default:
                        error = EOPNOTSUPP;
                        break;
                }
                break;
        case SOPT_SET:
        default:
                error = EOPNOTSUPP;
                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.
 */
#ifndef PIPSIZ
#define PIPSIZ  8192
#endif
static u_long   unpst_sendspace = PIPSIZ;
static u_long   unpst_recvspace = PIPSIZ;
static u_long   unpdg_sendspace = 2*1024;       /* really max datagram size */
static u_long   unpdg_recvspace = 4*1024;

static int      unp_rights;                     /* file descriptors in flight */
static struct spinlock unp_spin = SPINLOCK_INITIALIZER(&unp_spin);

SYSCTL_DECL(_net_local_stream);
SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 
           &unpst_sendspace, 0, "");
SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
           &unpst_recvspace, 0, "");

SYSCTL_DECL(_net_local_dgram);
SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
           &unpdg_sendspace, 0, "");
SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
           &unpdg_recvspace, 0, "");

SYSCTL_DECL(_net_local);
SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, "");

static int
unp_attach(struct socket *so, struct pru_attach_info *ai)
{
        struct unpcb *unp;
        int error;

        if (so->so_snd.ssb_hiwat == 0 || so->so_rcv.ssb_hiwat == 0) {
                switch (so->so_type) {

                case SOCK_STREAM:
                        error = soreserve(so, unpst_sendspace, unpst_recvspace,
                                          ai->sb_rlimit);
                        break;

                case SOCK_DGRAM:
                        error = soreserve(so, unpdg_sendspace, unpdg_recvspace,
                                          ai->sb_rlimit);
                        break;

                default:
                        panic("unp_attach");
                }
                if (error)
                        return (error);
        }
        unp = zalloc(unp_zone);
        if (unp == NULL)
                return (ENOBUFS);
        bzero(unp, sizeof *unp);
        unp->unp_gencnt = ++unp_gencnt;
        unp_count++;
        LIST_INIT(&unp->unp_refs);
        unp->unp_socket = so;
        unp->unp_rvnode = ai->fd_rdir;          /* jail cruft XXX JH */
        LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead
                         : &unp_shead, unp, unp_link);
        so->so_pcb = (caddr_t)unp;
        return (0);
}

static void
unp_detach(struct unpcb *unp)
{
        LIST_REMOVE(unp, unp_link);
        unp->unp_gencnt = ++unp_gencnt;
        --unp_count;
        if (unp->unp_vnode) {
                unp->unp_vnode->v_socket = NULL;
                vrele(unp->unp_vnode);
                unp->unp_vnode = NULL;
        }
        if (unp->unp_conn)
                unp_disconnect(unp);
        while (!LIST_EMPTY(&unp->unp_refs))
                unp_drop(LIST_FIRST(&unp->unp_refs), ECONNRESET);
        soisdisconnected(unp->unp_socket);
        unp->unp_socket->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(unp->unp_socket);
                unp_gc();
        }
        if (unp->unp_addr)
                kfree(unp->unp_addr, M_SONAME);
        zfree(unp_zone, unp);
}

static int
unp_bind(struct unpcb *unp, struct sockaddr *nam, struct thread *td)
{
        struct proc *p = td->td_proc;
        struct sockaddr_un *soun = (struct sockaddr_un *)nam;
        struct vnode *dvp;
        struct vnode *vp;
        struct vattr vattr;
        int error, namelen;
        struct nlookupdata nd;
        char buf[SOCK_MAXADDRLEN];

        if (unp->unp_vnode != NULL)
                return (EINVAL);
        namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
        if (namelen <= 0)
                return (EINVAL);
        strncpy(buf, soun->sun_path, namelen);
        buf[namelen] = 0;       /* null-terminate the string */
        error = nlookup_init(&nd, buf, UIO_SYSSPACE, NLC_LOCKVP|NLC_CREATE);
        if (error == 0)
                error = nlookup(&nd);
        if (error == 0 && nd.nl_nch.ncp->nc_vp != NULL)
                error = EADDRINUSE;
        if (error == 0 && (dvp = nd.nl_nch.ncp->nc_parent->nc_vp) == NULL)
                error = EPERM;
        if (error)
                goto done;

        /* vhold(dvp); - DVP can't go away */
        VATTR_NULL(&vattr);
        vattr.va_type = VSOCK;
        vattr.va_mode = (ACCESSPERMS & ~p->p_fd->fd_cmask);
        error = VOP_NCREATE(&nd.nl_nch, dvp, &vp, nd.nl_cred, &vattr);
        /* vdrop(dvp); */
        if (error == 0) {
                vp->v_socket = unp->unp_socket;
                unp->unp_vnode = vp;
                unp->unp_addr = (struct sockaddr_un *)dup_sockaddr(nam);
                vn_unlock(vp);
        }
done:
        nlookup_done(&nd);
        return (error);
}

static int
unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
        struct proc *p = td->td_proc;
        struct sockaddr_un *soun = (struct sockaddr_un *)nam;
        struct vnode *vp;
        struct socket *so2, *so3;
        struct unpcb *unp, *unp2, *unp3;
        int error, len;
        struct nlookupdata nd;
        char buf[SOCK_MAXADDRLEN];

        KKASSERT(p);

        len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
        if (len <= 0)
                return EINVAL;
        strncpy(buf, soun->sun_path, len);
        buf[len] = 0;

        vp = NULL;
        error = nlookup_init(&nd, buf, UIO_SYSSPACE, NLC_FOLLOW);
        if (error == 0)
                error = nlookup(&nd);
        if (error == 0)
                error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp);
        nlookup_done(&nd);
        if (error)
                return (error);

        if (vp->v_type != VSOCK) {
                error = ENOTSOCK;
                goto bad;
        }
        error = VOP_ACCESS(vp, VWRITE, p->p_ucred);
        if (error)
                goto bad;
        so2 = vp->v_socket;
        if (so2 == NULL) {
                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) ||
                    (so3 = sonewconn(so2, 0)) == NULL) {
                        error = ECONNREFUSED;
                        goto bad;
                }
                unp = so->so_pcb;
                unp2 = so2->so_pcb;
                unp3 = so3->so_pcb;
                if (unp2->unp_addr)
                        unp3->unp_addr = (struct sockaddr_un *)
                                dup_sockaddr((struct sockaddr *)unp2->unp_addr);

                /*
                 * unp_peercred management:
                 *
                 * The connecter's (client's) credentials are copied
                 * from its process structure at the time of connect()
                 * (which is now).
                 */
                cru2x(p->p_ucred, &unp3->unp_peercred);
                unp3->unp_flags |= UNP_HAVEPC;
                /*
                 * The receiver's (server's) credentials are copied
                 * from the unp_peercred member of socket on which the
                 * former called listen(); unp_listen() cached that
                 * process's credentials at that time so we can use
                 * them now.
                 */
                KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED,
                    ("unp_connect: listener without cached peercred"));
                memcpy(&unp->unp_peercred, &unp2->unp_peercred,
                    sizeof(unp->unp_peercred));
                unp->unp_flags |= UNP_HAVEPC;

                so2 = so3;
        }
        error = unp_connect2(so, so2);
bad:
        vput(vp);
        return (error);
}

int
unp_connect2(struct socket *so, struct socket *so2)
{
        struct unpcb *unp = so->so_pcb;
        struct unpcb *unp2;

        if (so2->so_type != so->so_type)
                return (EPROTOTYPE);
        unp2 = so2->so_pcb;
        unp->unp_conn = unp2;
        switch (so->so_type) {

        case SOCK_DGRAM:
                LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
                soisconnected(so);
                break;

        case SOCK_STREAM:
                unp2->unp_conn = unp;
                soisconnected(so);
                soisconnected(so2);
                break;

        default:
                panic("unp_connect2");
        }
        return (0);
}

static void
unp_disconnect(struct unpcb *unp)
{
        struct unpcb *unp2 = unp->unp_conn;

        if (unp2 == NULL)
                return;

        unp->unp_conn = NULL;

        switch (unp->unp_socket->so_type) {
        case SOCK_DGRAM:
                LIST_REMOVE(unp, unp_reflink);
                unp->unp_socket->so_state &= ~SS_ISCONNECTED;
                break;
        case SOCK_STREAM:
                soisdisconnected(unp->unp_socket);
                unp2->unp_conn = NULL;
                soisdisconnected(unp2->unp_socket);
                break;
        }
}

#ifdef notdef
void
unp_abort(struct unpcb *unp)
{

        unp_detach(unp);
}
#endif

static int
prison_unpcb(struct thread *td, struct unpcb *unp)
{
        struct proc *p;

        if (td == NULL)
                return (0);
        if ((p = td->td_proc) == NULL)
                return (0);
        if (!p->p_ucred->cr_prison)
                return (0);
        if (p->p_fd->fd_rdir == unp->unp_rvnode)
                return (0);
        return (1);
}

static int
unp_pcblist(SYSCTL_HANDLER_ARGS)
{
        int error, i, n;
        struct unpcb *unp, **unp_list;
        unp_gen_t gencnt;
        struct unp_head *head;

        head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead);

        KKASSERT(curproc != NULL);

        /*
         * The process of preparing the PCB list is too time-consuming and
         * resource-intensive to repeat twice on every request.
         */
        if (req->oldptr == NULL) {
                n = unp_count;
                req->oldidx = (n + n/8) * sizeof(struct xunpcb);
                return 0;
        }

        if (req->newptr != NULL)
                return EPERM;

        /*
         * OK, now we're committed to doing something.
         */
        gencnt = unp_gencnt;
        n = unp_count;

        unp_list = kmalloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
        
        for (unp = LIST_FIRST(head), i = 0; unp && i < n;
             unp = LIST_NEXT(unp, unp_link)) {
                if (unp->unp_gencnt <= gencnt && !prison_unpcb(req->td, unp))
                        unp_list[i++] = unp;
        }
        n = i;                  /* in case we lost some during malloc */

        error = 0;
        for (i = 0; i < n; i++) {
                unp = unp_list[i];
                if (unp->unp_gencnt <= gencnt) {
                        struct xunpcb xu;
                        xu.xu_len = sizeof xu;
                        xu.xu_unpp = unp;
                        /*
                         * XXX - need more locking here to protect against
                         * connect/disconnect races for SMP.
                         */
                        if (unp->unp_addr)
                                bcopy(unp->unp_addr, &xu.xu_addr, 
                                      unp->unp_addr->sun_len);
                        if (unp->unp_conn && unp->unp_conn->unp_addr)
                                bcopy(unp->unp_conn->unp_addr,
                                      &xu.xu_caddr,
                                      unp->unp_conn->unp_addr->sun_len);
                        bcopy(unp, &xu.xu_unp, sizeof *unp);
                        sotoxsocket(unp->unp_socket, &xu.xu_socket);
                        error = SYSCTL_OUT(req, &xu, sizeof xu);
                }
        }
        kfree(unp_list, M_TEMP);
        return error;
}

SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 
            (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
            "List of active local datagram sockets");
SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 
            (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
            "List of active local stream sockets");

static void
unp_shutdown(struct unpcb *unp)
{
        struct socket *so;

        if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn != NULL &&
            (so = unp->unp_conn->unp_socket))
                socantrcvmore(so);
}

static void
unp_drop(struct unpcb *unp, int err)
{
        struct socket *so = unp->unp_socket;

        so->so_error = err;
        unp_disconnect(unp);
}

#ifdef notdef
void
unp_drain(void)
{

}
#endif

int
unp_externalize(struct mbuf *rights)
{
        struct proc *p = curproc;               /* XXX */
        int i;
        struct cmsghdr *cm = mtod(rights, struct cmsghdr *);
        int *fdp;
        struct file **rp;
        struct file *fp;
        int newfds = (cm->cmsg_len - (CMSG_DATA(cm) - (u_char *)cm))
                / sizeof (struct file *);
        int f;

        /*
         * if the new FD's will not fit, then we free them all
         */
        if (!fdavail(p, newfds)) {
                rp = (struct file **)CMSG_DATA(cm);
                for (i = 0; i < newfds; i++) {
                        fp = *rp;
                        /*
                         * zero the pointer before calling unp_discard,
                         * since it may end up in unp_gc()..
                         */
                        *rp++ = 0;
                        unp_discard(fp, NULL);
                }
                return (EMSGSIZE);
        }
        /*
         * now change each pointer to an fd in the global table to 
         * an integer that is the index to the local fd table entry
         * that we set up to point to the global one we are transferring.
         * If sizeof (struct file *) is bigger than or equal to sizeof int,
         * then do it in forward order. In that case, an integer will
         * always come in the same place or before its corresponding
         * struct file pointer.
         * If sizeof (struct file *) is smaller than sizeof int, then
         * do it in reverse order.
         */
        if (sizeof (struct file *) >= sizeof (int)) {
                fdp = (int *)(cm + 1);
                rp = (struct file **)CMSG_DATA(cm);
                for (i = 0; i < newfds; i++) {
                        if (fdalloc(p, 0, &f))
                                panic("unp_externalize");
                        fp = *rp++;
                        fsetfd(p, fp, f);
                        fdrop(fp);
                        spin_lock_wr(&unp_spin);
                        fp->f_msgcount--;
                        unp_rights--;
                        spin_unlock_wr(&unp_spin);
                        *fdp++ = f;
                }
        } else {
                fdp = (int *)(cm + 1) + newfds - 1;
                rp = (struct file **)CMSG_DATA(cm) + newfds - 1;
                for (i = 0; i < newfds; i++) {
                        if (fdalloc(p, 0, &f))
                                panic("unp_externalize");
                        fp = *rp--;
                        fsetfd(p, fp, f);
                        fdrop(fp);
                        spin_lock_wr(&unp_spin);
                        fp->f_msgcount--;
                        unp_rights--;
                        spin_unlock_wr(&unp_spin);
                        *fdp-- = f;
                }
        }

        /*
         * Adjust length, in case sizeof(struct file *) and sizeof(int)
         * differs.
         */
        cm->cmsg_len = CMSG_LEN(newfds * sizeof(int));
        rights->m_len = cm->cmsg_len;
        return (0);
}

void
unp_init(void)
{
        unp_zone = zinit("unpcb", sizeof(struct unpcb), nmbclusters, 0, 0);
        if (unp_zone == NULL)
                panic("unp_init");
        LIST_INIT(&unp_dhead);
        LIST_INIT(&unp_shead);
        spin_init(&unp_spin);
}

static int
unp_internalize(struct mbuf *control, struct thread *td)
{
        struct proc *p = td->td_proc;
        struct filedesc *fdescp;
        struct cmsghdr *cm = mtod(control, struct cmsghdr *);
        struct file **rp;
        struct file *fp;
        int i, fd, *fdp;
        struct cmsgcred *cmcred;
        int oldfds;
        u_int newlen;

        KKASSERT(p);
        fdescp = p->p_fd;
        if ((cm->cmsg_type != SCM_RIGHTS && cm->cmsg_type != SCM_CREDS) ||
            cm->cmsg_level != SOL_SOCKET || cm->cmsg_len != control->m_len)
                return (EINVAL);

        /*
         * Fill in credential information.
         */
        if (cm->cmsg_type == SCM_CREDS) {
                cmcred = (struct cmsgcred *)(cm + 1);
                cmcred->cmcred_pid = p->p_pid;
                cmcred->cmcred_uid = p->p_ucred->cr_ruid;
                cmcred->cmcred_gid = p->p_ucred->cr_rgid;
                cmcred->cmcred_euid = p->p_ucred->cr_uid;
                cmcred->cmcred_ngroups = MIN(p->p_ucred->cr_ngroups,
                                                        CMGROUP_MAX);
                for (i = 0; i < cmcred->cmcred_ngroups; i++)
                        cmcred->cmcred_groups[i] = p->p_ucred->cr_groups[i];
                return(0);
        }

        oldfds = (cm->cmsg_len - sizeof (*cm)) / sizeof (int);
        /*
         * check that all the FDs passed in refer to legal OPEN files
         * If not, reject the entire operation.
         */
        fdp = (int *)(cm + 1);
        for (i = 0; i < oldfds; i++) {
                fd = *fdp++;
                if ((unsigned)fd >= fdescp->fd_nfiles ||
                    fdescp->fd_files[fd].fp == NULL)
                        return (EBADF);
                if (fdescp->fd_files[fd].fp->f_type == DTYPE_KQUEUE)
                        return (EOPNOTSUPP);
        }
        /*
         * Now replace the integer FDs with pointers to
         * the associated global file table entry..
         * Allocate a bigger buffer as necessary. But if an cluster is not
         * enough, return E2BIG.
         */
        newlen = CMSG_LEN(oldfds * sizeof(struct file *));
        if (newlen > MCLBYTES)
                return (E2BIG);
        if (newlen - control->m_len > M_TRAILINGSPACE(control)) {
                if (control->m_flags & M_EXT)
                        return (E2BIG);
                MCLGET(control, MB_WAIT);
                if (!(control->m_flags & M_EXT))
                        return (ENOBUFS);

                /* copy the data to the cluster */
                memcpy(mtod(control, char *), cm, cm->cmsg_len);
                cm = mtod(control, struct cmsghdr *);
        }

        /*
         * Adjust length, in case sizeof(struct file *) and sizeof(int)
         * differs.
         */
        control->m_len = cm->cmsg_len = newlen;

        /*
         * Transform the file descriptors into struct file pointers.
         * If sizeof (struct file *) is bigger than or equal to sizeof int,
         * then do it in reverse order so that the int won't get until
         * we're done.
         * If sizeof (struct file *) is smaller than sizeof int, then
         * do it in forward order.
         */
        if (sizeof (struct file *) >= sizeof (int)) {
                fdp = (int *)(cm + 1) + oldfds - 1;
                rp = (struct file **)CMSG_DATA(cm) + oldfds - 1;
                for (i = 0; i < oldfds; i++) {
                        fp = fdescp->fd_files[*fdp--].fp;
                        *rp-- = fp;
                        fhold(fp);
                        spin_lock_wr(&unp_spin);
                        fp->f_msgcount++;
                        unp_rights++;
                        spin_unlock_wr(&unp_spin);
                }
        } else {
                fdp = (int *)(cm + 1);
                rp = (struct file **)CMSG_DATA(cm);
                for (i = 0; i < oldfds; i++) {
                        fp = fdescp->fd_files[*fdp++].fp;
                        *rp++ = fp;
                        fhold(fp);
                        spin_lock_wr(&unp_spin);
                        fp->f_msgcount++;
                        unp_rights++;
                        spin_unlock_wr(&unp_spin);
                }
        }
        return (0);
}

/*
 * Garbage collect in-transit file descriptors that get lost due to
 * loops (i.e. when a socket is sent to another process over itself,
 * and more complex situations).
 *
 * NOT MPSAFE - TODO socket flush code and maybe closef.  Rest is MPSAFE.
 */

struct unp_gc_info {
        struct file **extra_ref;
        struct file *locked_fp;
        int defer;
        int index;
        int maxindex;
};

static void
unp_gc(void)
{
        struct unp_gc_info info;
        static boolean_t unp_gcing;
        struct file **fpp;
        int i;

        spin_lock_wr(&unp_spin);
        if (unp_gcing) {
                spin_unlock_wr(&unp_spin);
                return;
        }
        unp_gcing = TRUE;
        spin_unlock_wr(&unp_spin);

        /* 
         * before going through all this, set all FDs to 
         * be NOT defered and NOT externally accessible
         */
        info.defer = 0;
        allfiles_scan_exclusive(unp_gc_clearmarks, NULL);
        do {
                allfiles_scan_exclusive(unp_gc_checkmarks, &info);
        } while (info.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
         */
        info.extra_ref = kmalloc(256 * sizeof(struct file *), M_FILE, M_WAITOK);
        info.maxindex = 256;

        do {
                /*
                 * Look for matches
                 */
                info.index = 0;
                allfiles_scan_exclusive(unp_gc_checkrefs, &info);

                /* 
                 * For each FD on our hit list, do the following two things
                 */
                for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) {
                        struct file *tfp = *fpp;
                        if (tfp->f_type == DTYPE_SOCKET && tfp->f_data != NULL)
                                sorflush((struct socket *)(tfp->f_data));
                }
                for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp)
                        closef(*fpp, NULL);
        } while (info.index == info.maxindex);
        kfree((caddr_t)info.extra_ref, M_FILE);
        unp_gcing = FALSE;
}

/*
 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry
 */
static int
unp_gc_checkrefs(struct file *fp, void *data)
{
        struct unp_gc_info *info = data;

        if (fp->f_count == 0)
                return(0);
        if (info->index == info->maxindex)
                return(-1);

        /* 
         * If all refs are from msgs, and it's not marked accessible
         * then it must be referenced from some unreachable cycle
         * of (shut-down) FDs, so include it in our
         * list of FDs to remove
         */
        if (fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) {
                info->extra_ref[info->index++] = fp;
                fhold(fp);
        }
        return(0);
}

/*
 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry
 */
static int
unp_gc_clearmarks(struct file *fp, void *data __unused)
{
        fp->f_flag &= ~(FMARK|FDEFER);
        return(0);
}

/*
 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry
 */
static int
unp_gc_checkmarks(struct file *fp, void *data)
{
        struct unp_gc_info *info = data;
        struct socket *so;

        /*
         * If the file is not open, skip it
         */
        if (fp->f_count == 0)
                return(0);
        /*
         * If we already marked it as 'defer'  in a
         * previous pass, then try process it this time
         * and un-mark it
         */
        if (fp->f_flag & FDEFER) {
                fp->f_flag &= ~FDEFER;
                --info->defer;
        } else {
                /*
                 * if it's not defered, then check if it's
                 * already marked.. if so skip it
                 */
                if (fp->f_flag & FMARK)
                        return(0);
                /* 
                 * If all references are from messages
                 * in transit, then skip it. it's not 
                 * externally accessible.
                 */ 
                if (fp->f_count == fp->f_msgcount)
                        return(0);
                /* 
                 * If it got this far then it must be
                 * externally accessible.
                 */
                fp->f_flag |= FMARK;
        }
        /*
         * either it was defered, or it is externally 
         * accessible and not already marked so.
         * Now check if it is possibly one of OUR sockets.
         */ 
        if (fp->f_type != DTYPE_SOCKET ||
            (so = (struct socket *)fp->f_data) == NULL)
                return(0);
        if (so->so_proto->pr_domain != &localdomain ||
            !(so->so_proto->pr_flags & PR_RIGHTS))
                return(0);
#ifdef notdef
        XXX note: exclusive fp->f_spin lock held
        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.
                 */
                sbwait(&so->so_rcv);
                goto restart;
        }
#endif
        /*
         * So, Ok, it's one of our sockets and it IS externally
         * accessible (or was defered). Now we look
         * to see if we hold any file descriptors in its
         * message buffers. Follow those links and mark them 
         * as accessible too.
         */
        info->locked_fp = fp;
/*      spin_lock_wr(&so->so_rcv.sb_spin); */
        unp_scan(so->so_rcv.ssb_mb, unp_mark, info);
/*      spin_unlock_wr(&so->so_rcv.sb_spin);*/
        return (0);
}

void
unp_dispose(struct mbuf *m)
{
        if (m)
                unp_scan(m, unp_discard, NULL);
}

static int
unp_listen(struct unpcb *unp, struct thread *td)
{
        struct proc *p = td->td_proc;

        KKASSERT(p);
        cru2x(p->p_ucred, &unp->unp_peercred);
        unp->unp_flags |= UNP_HAVEPCCACHED;
        return (0);
}

static void
unp_scan(struct mbuf *m0, void (*op)(struct file *, void *), void *data)
{
        struct mbuf *m;
        struct file **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_DATA(cm) - (u_char *)cm))
                                                / sizeof (struct file *);
                                rp = (struct file **)CMSG_DATA(cm);
                                for (i = 0; i < qfds; i++)
                                        (*op)(*rp++, data);
                                break;          /* XXX, but saves time */
                        }
                }
                m0 = m0->m_nextpkt;
        }
}

static void
unp_mark(struct file *fp, void *data)
{
        struct unp_gc_info *info = data;

        if (info->locked_fp != fp)
                spin_lock_wr(&fp->f_spin);
        if ((fp->f_flag & FMARK) == 0) {
                ++info->defer;
                fp->f_flag |= (FMARK|FDEFER);
        }
        if (info->locked_fp != fp)
                spin_unlock_wr(&fp->f_spin);
}

static void
unp_discard(struct file *fp, void *data __unused)
{
        spin_lock_wr(&unp_spin);
        fp->f_msgcount--;
        unp_rights--;
        spin_unlock_wr(&unp_spin);
        closef(fp, NULL);
}