HAMMER 60I/Many: Mirroring

[dragonfly.git] / sys / vfs / portal / portal_vnops.c

/*
 * 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      8.14 (Berkeley) 5/21/95
 *
 * $FreeBSD: src/sys/miscfs/portal/portal_vnops.c,v 1.38 1999/12/21 06:29:00 chris Exp $
 * $DragonFly: src/sys/vfs/portal/portal_vnops.c,v 1.39 2007/11/20 21:03:50 dillon Exp $
 */

/*
 * Portal Filesystem
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/vnode.h>
#include <sys/fcntl.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/resourcevar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include "portal.h"

#include <sys/thread2.h>

static int portal_fileid = PORTAL_ROOTFILEID+1;

static int      portal_badop (void);
static void     portal_closefd (struct thread *td, int fd);
static int      portal_connect (struct socket *so, struct socket *so2);
static int      portal_getattr (struct vop_getattr_args *ap);
static int      portal_inactive (struct vop_inactive_args *ap);
static int      portal_lookup (struct vop_old_lookup_args *ap);
static int      portal_open (struct vop_open_args *ap);
static int      portal_print (struct vop_print_args *ap);
static int      portal_readdir (struct vop_readdir_args *ap);
static int      portal_reclaim (struct vop_reclaim_args *ap);
static int      portal_setattr (struct vop_setattr_args *ap);

static void
portal_closefd(struct thread *td, int fd)
{
        int error;
        struct close_args ua;

        ua.fd = fd;
        error = sys_close(&ua);
        /*
         * 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)
                kprintf("portal_closefd: error = %d\n", error);
}

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

        *vpp = NULLVP;

        if (cnp->cn_nameiop == NAMEI_DELETE || cnp->cn_nameiop == NAMEI_RENAME)
                return (EROFS);

        if (cnp->cn_namelen == 1 && *pname == '.') {
                *vpp = dvp;
                vref(dvp);
                return (0);
        }

        /*
         * Do the MALLOC before the getnewvnode since doing so afterward
         * might cause a bogus v_data pointer to get dereferenced
         * elsewhere if MALLOC should block.
         */
        MALLOC(pt, struct portalnode *, sizeof(struct portalnode),
                M_TEMP, M_WAITOK);

        error = getnewvnode(VT_PORTAL, dvp->v_mount, &fvp, 0, 0);
        if (error) {
                FREE(pt, M_TEMP);
                goto bad;
        }
        fvp->v_type = VREG;
        fvp->v_data = pt;

        /*
         * 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++;
        cnp->cn_consume = size - cnp->cn_namelen;

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

        *vpp = fvp;
        vx_unlock(fvp);
        return (0);

bad:;
        if (fvp)
                vrele(fvp);
        return (error);
}

static int
portal_connect(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 = so2->so_pcb;
        unp3 = so3->so_pcb;
        if (unp2->unp_addr)
                unp3->unp_addr = (struct sockaddr_un *)
                        dup_sockaddr((struct sockaddr *)unp2->unp_addr);
        so2 = so3;

        return (unp_connect2(so, so2));
}

/*
 * portal_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
 *             struct file *a_fp)
 */
static int
portal_open(struct vop_open_args *ap)
{
        struct socket *so = 0;
        struct portalnode *pt;
        struct thread *td = curthread;
        struct vnode *vp = ap->a_vp;
        struct uio auio;
        struct iovec aiov[2];
        struct sockbuf sio;
        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 (vop_stdopen(ap));

        /*
         * 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.
         */
        KKASSERT(td->td_proc);
        if (td->td_lwp->lwp_dupfd >= 0)
                return (ENODEV);

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

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

        /*
         * Reserve some buffer space
         */
        res = pt->pt_size + sizeof(pcred) + 512;        /* XXX */
        error = soreserve(so, res, res, &td->td_proc->p_rlimit[RLIMIT_SBSIZE]);
        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.
         */
        crit_enter();
        while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
                if (fmp->pm_server->f_count == 1) {
                        error = ECONNREFUSED;
                        crit_exit();
                        goto bad;
                }
                (void) tsleep((caddr_t) &so->so_timeo, 0, "portalcon", 5 * hz);
        }
        crit_exit();

        if (so->so_error) {
                error = so->so_error;
                goto bad;
        }

        /*
         * Set miscellaneous flags
         */
        so->so_rcv.ssb_timeo = 0;
        so->so_snd.ssb_timeo = 0;
        so->so_rcv.ssb_flags |= SSB_NOINTR;
        so->so_snd.ssb_flags |= SSB_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_td = td;
        auio.uio_offset = 0;
        auio.uio_resid = aiov[0].iov_len + aiov[1].iov_len;

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

        len = sizeof(int);
        sbinit(&sio, len);
        do {
                struct mbuf *m;
                int flags;

                flags = MSG_WAITALL;
                error = soreceive(so, NULL, NULL, &sio, &cm, &flags);
                if (error)
                        goto bad;

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

        if (cm == NULL)
                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?
         */
        cmsg = mtod(cm, struct cmsghdr *);
        newfds = (cmsg->cmsg_len - sizeof(*cmsg)) / sizeof (int);
        if (newfds == 0) {
                error = ECONNREFUSED;
                goto bad;
        }
        /*
         * At this point the rights message consists of a control message
         * header, followed by a data region containing a vector of
         * integer file descriptors.  The fds were allocated by the action
         * of receiving the control message.
         */
        ip = (int *) (cmsg + 1);
        fd = *ip++;
        if (newfds > 1) {
                /*
                 * Close extra fds.
                 */
                int i;
                kprintf("portal_open: %d extra fds\n", newfds - 1);
                for (i = 1; i < newfds; i++) {
                        portal_closefd(td, *ip);
                        ip++;
                }
        }

        /*
         * Check that the mode the file is being opened for is a subset
         * of the mode of the existing descriptor.
         */
        KKASSERT(td->td_proc);
        fp = td->td_proc->p_fd->fd_files[fd].fp;
        if (((ap->a_mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) {
                portal_closefd(td, fd);
                error = EACCES;
                goto bad;
        }

        /*
         * Save the dup fd in the proc structure then return the
         * special error code (ENXIO) which causes magic things to
         * happen in vn_open.  The whole concept is, well, hmmm.
         */
        td->td_lwp->lwp_dupfd = fd;
        vop_stdopen(ap);
        error = ENXIO;

bad:;
        /*
         * And discard the control message.
         */
        if (cm) {
                m_freem(cm);
        }

        if (so) {
                soshutdown(so, SHUT_RDWR);
                soclose(so, FNONBLOCK);
        }
        return (error);
}

/*
 * portal_getattr(struct vnode *a_vp, struct vattr *a_vap)
 */
static int
portal_getattr(struct vop_getattr_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct vattr *vap = ap->a_vap;

        bzero(vap, sizeof(*vap));
        vattr_null(vap);
        vap->va_uid = 0;
        vap->va_gid = 0;
        vap->va_size = DEV_BSIZE;
        vap->va_blocksize = DEV_BSIZE;
        nanotime(&vap->va_atime);
        vap->va_mtime = vap->va_atime;
        vap->va_ctime = vap->va_mtime;
        vap->va_gen = 0;
        vap->va_flags = 0;
        vap->va_rmajor = VNOVAL;
        vap->va_rminor = VNOVAL;
        /* vap->va_qbytes = 0; */
        vap->va_bytes = 0;
        /* vap->va_qsize = 0; */
        if (vp->v_flag & VROOT) {
                vap->va_type = VDIR;
                vap->va_mode = S_IRUSR|S_IWUSR|S_IXUSR|
                                S_IRGRP|S_IWGRP|S_IXGRP|
                                S_IROTH|S_IWOTH|S_IXOTH;
                vap->va_nlink = 2;
                vap->va_fileid = 2;
        } else {
                vap->va_type = VREG;
                vap->va_mode = S_IRUSR|S_IWUSR|
                                S_IRGRP|S_IWGRP|
                                S_IROTH|S_IWOTH;
                vap->va_nlink = 1;
                vap->va_fileid = VTOPORTAL(vp)->pt_fileid;
        }
        return (0);
}

/*
 * portal_setattr(struct vnode *a_vp, struct vattr *a_vap,
 *                struct ucred *a_cred)
 */
static int
portal_setattr(struct vop_setattr_args *ap)
{
        /*
         * Can't mess with the root vnode
         */
        if (ap->a_vp->v_flag & VROOT)
                return (EACCES);

        if (ap->a_vap->va_flags != VNOVAL)
                return (EOPNOTSUPP);

        return (0);
}

/*
 * Fake readdir, just return empty directory.
 * It is hard to deal with '.' and '..' so don't bother.
 *
 * portal_readdir(struct vnode *a_vp, struct uio *a_uio,
 *                struct ucred *a_cred, int *a_eofflag,
 *                off_t *a_cookies, int a_ncookies)
 */
static int
portal_readdir(struct vop_readdir_args *ap)
{
        /*
         * We don't allow exporting portal mounts, and currently local
         * requests do not need cookies.
         */
        if (ap->a_ncookies)
                panic("portal_readdir: not hungry");

        return (0);
}

/*
 * portal_inactive(struct vnode *a_vp)
 */
static int
portal_inactive(struct vop_inactive_args *ap)
{
        return (0);
}

/*
 * portal_reclaim(struct vnode *a_vp)
 */
static int
portal_reclaim(struct vop_reclaim_args *ap)
{
        struct portalnode *pt = VTOPORTAL(ap->a_vp);

        if (pt->pt_arg) {
                kfree((caddr_t) pt->pt_arg, M_TEMP);
                pt->pt_arg = 0;
        }
        FREE(ap->a_vp->v_data, M_TEMP);
        ap->a_vp->v_data = 0;

        return (0);
}


/*
 * Print out the contents of a Portal vnode.
 *
 * portal_print(struct vnode *a_vp)
 */
/* ARGSUSED */
static int
portal_print(struct vop_print_args *ap)
{
        kprintf("tag VT_PORTAL, portal vnode\n");
        return (0);
}


/*
 * Portal "should never get here" operation
 */
static int
portal_badop(void)
{

        panic("portal: bad op");
        /* NOTREACHED */
}

struct vop_ops portal_vnode_vops = {
        .vop_default =          vop_defaultop,
        .vop_access =           (void *)vop_null,
        .vop_bmap =             (void *)portal_badop,
        .vop_getattr =          portal_getattr,
        .vop_inactive =         portal_inactive,
        .vop_old_lookup =       portal_lookup,
        .vop_open =             portal_open,
        .vop_pathconf =         vop_stdpathconf,
        .vop_print =            portal_print,
        .vop_readdir =          portal_readdir,
        .vop_reclaim =          portal_reclaim,
        .vop_setattr =          portal_setattr
};