portal_vnops.c

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/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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.
 *
 *	@(#)portal_vnops.c	8.8 (Berkeley) 1/21/94
 *
 * $Id: portal_vnops.c,v 1.4 1992/05/30 10:05:24 jsp Exp jsp $
 */

/*
 * Portal Filesystem
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <miscfs/portal/portal.h>

static int portal_fileid = PORTAL_ROOTFILEID+1;

static void
portal_closefd(p, fd)
	struct proc *p;
	int fd;
{
	int error;
	struct {
		int fd;
	} ua;
	int rc;

	ua.fd = fd;
	error = close(p, &ua, &rc);
	/*
	 * We should never get an error, and there isn't anything
	 * we could do if we got one, so just print a message.
	 */
	if (error)
		printf("portal_closefd: error = %d\n", error);
}

/*
 * vp is the current namei directory
 * cnp is the name to locate in that directory...
 */
int
portal_lookup(ap)
	struct vop_lookup_args /* {
		struct vnode * a_dvp;
		struct vnode ** a_vpp;
		struct componentname * a_cnp;
	} */ *ap;
{
	char *pname = ap->a_cnp->cn_nameptr;
	struct portalnode *pt;
	int error;
	struct vnode *fvp = 0;
	char *path;
	int size;

	if (ap->a_cnp->cn_namelen == 1 && *pname == '.') {
		*ap->a_vpp = ap->a_dvp;
		VREF(ap->a_dvp);
		/*VOP_LOCK(ap->a_dvp);*/
		return (0);
	}


	error = getnewvnode(VT_PORTAL, ap->a_dvp->v_mount, portal_vnodeop_p, &fvp);
	if (error)
		goto bad;
	fvp->v_type = VREG;
	MALLOC(fvp->v_data, void *, sizeof(struct portalnode),
		M_TEMP, M_WAITOK);

	pt = VTOPORTAL(fvp);
	/*
	 * Save all of the remaining pathname and
	 * advance the namei next pointer to the end
	 * of the string.
	 */
	for (size = 0, path = pname; *path; path++)
		size++;
	ap->a_cnp->cn_consume = size - ap->a_cnp->cn_namelen;

	pt->pt_arg = malloc(size+1, M_TEMP, M_WAITOK);
	pt->pt_size = size+1;
	bcopy(pname, pt->pt_arg, pt->pt_size);
	pt->pt_fileid = portal_fileid++;

	*ap->a_vpp = fvp;
	/*VOP_LOCK(fvp);*/
	return (0);

bad:;
	if (fvp) {
		vrele(fvp);
	}
	*ap->a_vpp = NULL;
	return (error);
}

static int
portal_connect(so, so2)
	struct socket *so;
	struct socket *so2;
{
	/* from unp_connect, bypassing the namei stuff... */
	struct socket *so3;
	struct unpcb *unp2;
	struct unpcb *unp3;

	if (so2 == 0)
		return (ECONNREFUSED);

	if (so->so_type != so2->so_type)
		return (EPROTOTYPE);

	if ((so2->so_options & SO_ACCEPTCONN) == 0)
		return (ECONNREFUSED);

	if ((so3 = sonewconn(so2, 0)) == 0)
		return (ECONNREFUSED);

	unp2 = sotounpcb(so2);
	unp3 = sotounpcb(so3);
	if (unp2->unp_addr)
		unp3->unp_addr = m_copy(unp2->unp_addr, 0, (int)M_COPYALL);

	so2 = so3;


	return (unp_connect2(so, so2));
}

int
portal_open(ap)
	struct vop_open_args /* {
		struct vnode *a_vp;
		int  a_mode;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct socket *so = 0;
	struct portalnode *pt;
	struct proc *p = ap->a_p;
	struct vnode *vp = ap->a_vp;
	int s;
	struct uio auio;
	struct iovec aiov[2];
	int res;
	struct mbuf *cm = 0;
	struct cmsghdr *cmsg;
	int newfds;
	int *ip;
	int fd;
	int error;
	int len;
	struct portalmount *fmp;
	struct file *fp;
	struct portal_cred pcred;

	/*
	 * Nothing to do when opening the root node.
	 */
	if (vp->v_flag & VROOT)
		return (0);

	/*
	 * Can't be opened unless the caller is set up
	 * to deal with the side effects.  Check for this
	 * by testing whether the p_dupfd has been set.
	 */
	if (p->p_dupfd >= 0)
		return (ENODEV);

	pt = VTOPORTAL(vp);
	fmp = VFSTOPORTAL(vp->v_mount);

	/*
	 * Create a new socket.
	 */
	error = socreate(AF_UNIX, &so, SOCK_STREAM, 0);
	if (error)
		goto bad;

	/*
	 * Reserve some buffer space
	 */
	res = pt->pt_size + sizeof(pcred) + 512;	/* XXX */
	error = soreserve(so, res, res);
	if (error)
		goto bad;

	/*
	 * Kick off connection
	 */
	error = portal_connect(so, (struct socket *)fmp->pm_server->f_data);
	if (error)
		goto bad;

	/*
	 * Wait for connection to complete
	 */
	/*
	 * XXX: Since the mount point is holding a reference on the
	 * underlying server socket, it is not easy to find out whether
	 * the server process is still running.  To handle this problem
	 * we loop waiting for the new socket to be connected (something
	 * which will only happen if the server is still running) or for
	 * the reference count on the server socket to drop to 1, which
	 * will happen if the server dies.  Sleep for 5 second intervals
	 * and keep polling the reference count.   XXX.
	 */
	s = splnet();
	while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
		if (fmp->pm_server->f_count == 1) {
			error = ECONNREFUSED;
			splx(s);
			goto bad;
		}
		(void) tsleep((caddr_t) &so->so_timeo, PSOCK, "portalcon", 5 * hz);
	}
	splx(s);

	if (so->so_error) {
		error = so->so_error;
		goto bad;
	}
		
	/*
	 * Set miscellaneous flags
	 */
	so->so_rcv.sb_timeo = 0;
	so->so_snd.sb_timeo = 0;
	so->so_rcv.sb_flags |= SB_NOINTR;
	so->so_snd.sb_flags |= SB_NOINTR;


	pcred.pcr_flag = ap->a_mode;
	pcred.pcr_uid = ap->a_cred->cr_uid;
	pcred.pcr_ngroups = ap->a_cred->cr_ngroups;
	bcopy(ap->a_cred->cr_groups, pcred.pcr_groups, NGROUPS * sizeof(gid_t));
	aiov[0].iov_base = (caddr_t) &pcred;
	aiov[0].iov_len = sizeof(pcred);
	aiov[1].iov_base = pt->pt_arg;
	aiov[1].iov_len = pt->pt_size;
	auio.uio_iov = aiov;
	auio.uio_iovcnt = 2;
	auio.uio_rw = UIO_WRITE;
	auio.uio_segflg = UIO_SYSSPACE;
	auio.uio_procp = p;
	auio.uio_offset = 0;
	auio.uio_resid = aiov[0].iov_len + aiov[1].iov_len;

	error = sosend(so, (struct mbuf *) 0, &auio,
			(struct mbuf *) 0, (struct mbuf *) 0, 0);
	if (error)
		goto bad;

	len = auio.uio_resid = sizeof(int);
	do {
		struct mbuf *m = 0;
		int flags = MSG_WAITALL;
		error = soreceive(so, (struct mbuf **) 0, &auio,
					&m, &cm, &flags);
		if (error)
			goto bad;

		/*
		 * Grab an error code from the mbuf.
		 */
		if (m) {
			m = m_pullup(m, sizeof(int));	/* Needed? */
			if (m) {
				error = *(mtod(m, int *));
				m_freem(m);
			} else {
				error = EINVAL;
			}
		} else {
			if (cm == 0) {
				error = ECONNRESET;	 /* XXX */
#ifdef notdef
				break;
#endif
			}
		}
	} while (cm == 0 && auio.uio_resid == len && !error);

	if (cm == 0)
		goto bad;

	if (auio.uio_resid) {
		error = 0;
#ifdef notdef
		error = EMSGSIZE;
		goto bad;
#endif
	}

	/*
	 * XXX: Break apart the control message, and retrieve the
	 * received file descriptor.  Note that more than one descriptor
	 * may have been received, or that the rights chain may have more
	 * than a single mbuf in it.  What to do?
	 */