/* * 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 * $Id: uipc_usrreq.c,v 1.37 1998/10/25 17:44:51 phk Exp $ */ #include #include #include #include #include #include /* XXX must be before */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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 __P((struct socket *)); static void unp_detach __P((struct unpcb *)); static int unp_bind __P((struct unpcb *,struct sockaddr *, struct proc *)); static int unp_connect __P((struct socket *,struct sockaddr *, struct proc *)); static void unp_disconnect __P((struct unpcb *)); static void unp_shutdown __P((struct unpcb *)); static void unp_drop __P((struct unpcb *, int)); static void unp_gc __P((void)); static void unp_scan __P((struct mbuf *, void (*)(struct file *))); static void unp_mark __P((struct file *)); static void unp_discard __P((struct file *)); static int unp_internalize __P((struct mbuf *, struct proc *)); static int uipc_abort(struct socket *so) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; unp_drop(unp, ECONNABORTED); return 0; } static int uipc_accept(struct socket *so, struct sockaddr **nam) { struct unpcb *unp = sotounpcb(so); if (unp == 0) 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, 1); } else { *nam = dup_sockaddr((struct sockaddr *)&sun_noname, 1); } return 0; } static int uipc_attach(struct socket *so, int proto, struct proc *p) { struct unpcb *unp = sotounpcb(so); if (unp != 0) return EISCONN; return unp_attach(so); } static int uipc_bind(struct socket *so, struct sockaddr *nam, struct proc *p) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; return unp_bind(unp, nam, p); } static int uipc_connect(struct socket *so, struct sockaddr *nam, struct proc *p) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; return unp_connect(so, nam, curproc); } static int uipc_connect2(struct socket *so1, struct socket *so2) { struct unpcb *unp = sotounpcb(so1); if (unp == 0) return EINVAL; return unp_connect2(so1, so2); } /* control is EOPNOTSUPP */ static int uipc_detach(struct socket *so) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; unp_detach(unp); return 0; } static int uipc_disconnect(struct socket *so) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; unp_disconnect(unp); return 0; } static int uipc_listen(struct socket *so, struct proc *p) { struct unpcb *unp = sotounpcb(so); if (unp == 0 || unp->unp_vnode == 0) return EINVAL; return 0; } static int uipc_peeraddr(struct socket *so, struct sockaddr **nam) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; if (unp->unp_conn && unp->unp_conn->unp_addr) *nam = dup_sockaddr((struct sockaddr *)unp->unp_conn->unp_addr, 1); return 0; } static int uipc_rcvd(struct socket *so, int flags) { struct unpcb *unp = sotounpcb(so); struct socket *so2; if (unp == 0) return EINVAL; switch (so->so_type) { case SOCK_DGRAM: panic("uipc_rcvd DGRAM?"); /*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; /* * 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; snd->sb_hiwat += unp->unp_cc - rcv->sb_cc; unp->unp_cc = rcv->sb_cc; sowwakeup(so2); #undef snd #undef rcv 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 proc *p) { int error = 0; struct unpcb *unp = sotounpcb(so); struct socket *so2; if (unp == 0) { error = EINVAL; goto release; } if (flags & PRUS_OOB) { error = EOPNOTSUPP; goto release; } if (control && (error = unp_internalize(control, p))) 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, p); if (error) break; } else { if (unp->unp_conn == 0) { error = ENOTCONN; break; } } so2 = unp->unp_conn->unp_socket; if (unp->unp_addr) from = (struct sockaddr *)unp->unp_addr; else from = &sun_noname; if (sbappendaddr(&so2->so_rcv, from, m, control)) { sorwakeup(so2); m = 0; control = 0; } else error = ENOBUFS; if (nam) unp_disconnect(unp); break; } case SOCK_STREAM: #define rcv (&so2->so_rcv) #define snd (&so->so_snd) /* 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) == 0) { if (nam) { error = unp_connect(so, nam, p); if (error) break; /* XXX */ } else { error = ENOTCONN; break; } } if (so->so_state & SS_CANTSENDMORE) { error = EPIPE; break; } if (unp->unp_conn == 0) 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 (sbappendcontrol(rcv, m, control)) control = 0; } else sbappend(rcv, m); snd->sb_mbmax -= rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt; unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt; snd->sb_hiwat -= rcv->sb_cc - unp->unp_conn->unp_cc; unp->unp_conn->unp_cc = rcv->sb_cc; sorwakeup(so2); m = 0; #undef snd #undef rcv 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); } 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 = sotounpcb(so); struct socket *so2; if (unp == 0) return EINVAL; sb->st_blksize = so->so_snd.sb_hiwat; if (so->so_type == SOCK_STREAM && unp->unp_conn != 0) { so2 = unp->unp_conn->unp_socket; sb->st_blksize += so2->so_rcv.sb_cc; } sb->st_dev = NODEV; if (unp->unp_ino == 0) unp->unp_ino = unp_ino++; sb->st_ino = unp->unp_ino; return (0); } static int uipc_shutdown(struct socket *so) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; socantsendmore(so); unp_shutdown(unp); return 0; } static int uipc_sockaddr(struct socket *so, struct sockaddr **nam) { struct unpcb *unp = sotounpcb(so); if (unp == 0) return EINVAL; if (unp->unp_addr) *nam = dup_sockaddr((struct sockaddr *)unp->unp_addr, 1); return 0; } struct pr_usrreqs uipc_usrreqs = { uipc_abort, uipc_accept, uipc_attach, uipc_bind, uipc_connect, uipc_connect2, pru_control_notsupp, uipc_detach, uipc_disconnect, uipc_listen, uipc_peeraddr, uipc_rcvd, pru_rcvoob_notsupp, uipc_send, uipc_sense, uipc_shutdown, uipc_sockaddr, sosend, soreceive, sopoll }; /* * 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 */ 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_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_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); static int unp_attach(so) struct socket *so; { register struct unpcb *unp; int error; if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { switch (so->so_type) { case SOCK_STREAM: error = soreserve(so, unpst_sendspace, unpst_recvspace); break; case SOCK_DGRAM: error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 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; 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(unp) register struct unpcb *unp; { LIST_REMOVE(unp, unp_link); unp->unp_gencnt = ++unp_gencnt; --unp_count; if (unp->unp_vnode) { unp->unp_vnode->v_socket = 0; vrele(unp->unp_vnode); unp->unp_vnode = 0; } if (unp->unp_conn) unp_disconnect(unp); while (unp->unp_refs.lh_first) unp_drop(unp->unp_refs.lh_first, ECONNRESET); soisdisconnected(unp->unp_socket); unp->unp_socket->so_pcb = 0; 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) FREE(unp->unp_addr, M_SONAME); zfree(unp_zone, unp); } static int unp_bind(unp, nam, p) struct unpcb *unp; struct sockaddr *nam; struct proc *p; { struct sockaddr_un *soun = (struct sockaddr_un *)nam; register struct vnode *vp; struct vattr vattr; int error, namelen; struct nameidata nd; char buf[SOCK_MAXADDRLEN]; if (unp->unp_vnode != NULL) return (EINVAL); #define offsetof(s, e) ((char *)&((s *)0)->e - (char *)((s *)0)) 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 */ NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT, UIO_SYSSPACE, buf, p); /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ error = namei(&nd); if (error) 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 & ~p->p_fd->fd_cmask); VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE); error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); vput(nd.ni_dvp); if (error) return (error); vp = nd.ni_vp; vp->v_socket = unp->unp_socket; unp->unp_vnode = vp; unp->unp_addr = (struct sockaddr_un *)dup_sockaddr(nam, 1); VOP_UNLOCK(vp, 0, p); return (0); } static int unp_connect(so, nam, p) struct socket *so; struct sockaddr *nam; struct proc *p; { register struct sockaddr_un *soun = (struct sockaddr_un *)nam; register struct vnode *vp; register struct socket *so2, *so3; struct unpcb *unp2, *unp3; int error, len; struct nameidata nd; char buf[SOCK_MAXADDRLEN]; len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); if (len <= 0) return EINVAL; strncpy(buf, soun->sun_path, len); buf[len] = 0; NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, p); error = namei(&nd); if (error) return (error); vp = nd.ni_vp; if (vp->v_type != VSOCK) { error = ENOTSOCK; goto bad; } error = VOP_ACCESS(vp, VWRITE, p->p_ucred, p); if (error) 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 = (struct sockaddr_un *) dup_sockaddr((struct sockaddr *) unp2->unp_addr, 1); 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: 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(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: LIST_REMOVE(unp, unp_reflink); 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 static int unp_pcblist SYSCTL_HANDLER_ARGS { int error, i, n; struct unpcb *unp, **unp_list; unp_gen_t gencnt; struct xunpgen xug; struct unp_head *head; head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); /* * The process of preparing the PCB list is too time-consuming and * resource-intensive to repeat twice on every request. */ if (req->oldptr == 0) { n = unp_count; req->oldidx = 2 * (sizeof xug) + (n + n/8) * sizeof(struct xunpcb); return 0; } if (req->newptr != 0) return EPERM; /* * OK, now we're committed to doing something. */ gencnt = unp_gencnt; n = unp_count; xug.xug_len = sizeof xug; xug.xug_count = n; xug.xug_gen = gencnt; xug.xug_sogen = so_gencnt; error = SYSCTL_OUT(req, &xug, sizeof xug); if (error) return error; unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); if (unp_list == 0) return ENOMEM; for (unp = head->lh_first, i = 0; unp && i < n; unp = unp->unp_link.le_next) { if (unp->unp_gencnt <= gencnt) 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); } } if (!error) { /* * Give the user an updated idea of our state. * If the generation differs from what we told * her before, she knows that something happened * while we were processing this request, and it * might be necessary to retry. */ xug.xug_gen = unp_gencnt; xug.xug_sogen = so_gencnt; xug.xug_count = unp_count; error = SYSCTL_OUT(req, &xug, sizeof xug); } free(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(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); } static 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) { LIST_REMOVE(unp, unp_link); unp->unp_gencnt = ++unp_gencnt; unp_count--; so->so_pcb = (caddr_t) 0; if (unp->unp_addr) FREE(unp->unp_addr, M_SONAME); zfree(unp_zone, 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 the new FD's will not fit, then we free them all */ if (!fdavail(p, newfds)) { for (i = 0; i < newfds; i++) { fp = *rp; unp_discard(fp); *rp++ = 0; } 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. * XXX this assumes a pointer and int are the same size...! */ 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); } void unp_init(void) { unp_zone = zinit("unpcb", sizeof(struct unpcb), nmbclusters, 0, 0); if (unp_zone == 0) panic("unp_init"); LIST_INIT(&unp_dhead); LIST_INIT(&unp_shead); } #ifndef MIN #define MIN(a,b) (((a)<(b))?(a):(b)) #endif static 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; register struct cmsgcred *cmcred; int oldfds; 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_cred->p_ruid; cmcred->cmcred_gid = p->p_cred->p_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. */ 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); } /* * Now replace the integer FDs with pointers to * the associated global file table entry.. * XXX this assumes a pointer and an int are the same size! */ 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); } static int unp_defer, unp_gcing; static 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; /* * before going through all this, set all FDs to * be NOT defered and NOT externally accessible */ for (fp = filehead.lh_first; fp != 0; fp = fp->f_list.le_next) fp->f_flag &= ~(FMARK|FDEFER); do { for (fp = filehead.lh_first; fp != 0; fp = fp->f_list.le_next) { /* * If the file is not open, skip it */ if (fp->f_count == 0) continue; /* * 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; unp_defer--; } else { /* * if it's not defered, then check if it's * already marked.. if so skip it */ if (fp->f_flag & FMARK) continue; /* * If all references are from messages * in transit, then skip it. it's not * externally accessible. */ if (fp->f_count == fp->f_msgcount) continue; /* * 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) == 0) continue; if (so->so_proto->pr_domain != &localdomain || (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 /* * 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. */ 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.lh_first, fpp = extra_ref; fp != 0; fp = nextfp) { nextfp = fp->f_list.le_next; /* * If it's not open, skip it */ if (fp->f_count == 0) continue; /* * 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)) { *fpp++ = fp; nunref++; fp->f_count++; } } /* * for each FD on our hit list, do the following two things */ for (i = nunref, fpp = 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 = 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); } static void unp_scan(m0, op) register struct mbuf *m0; void (*op) __P((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; } } static void unp_mark(fp) struct file *fp; { if (fp->f_flag & FMARK) return; unp_defer++; fp->f_flag |= (FMARK|FDEFER); } static void unp_discard(fp) struct file *fp; { fp->f_msgcount--; unp_rights--; (void) closef(fp, (struct proc *)NULL); }