/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2017 by Delphix. All rights reserved.
 * Copyright 2021 Racktop Systems, Inc.
 */

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bitmap.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/strsubr.h>
#include <sys/cmn_err.h>
#include <sys/sysmacros.h>
#include <sys/filio.h>
#include <sys/flock.h>
#include <sys/stat.h>
#include <sys/share.h>

#include <sys/vfs.h>
#include <sys/vfs_opreg.h>

#include <sys/sockio.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/strsun.h>

#include <fs/sockfs/sockcommon.h>
#include <fs/sockfs/socktpi.h>

/*
 * Generic vnode ops
 */
static int      socket_vop_open(struct vnode **, int, struct cred *,
                    caller_context_t *);
static int      socket_vop_close(struct vnode *, int, int, offset_t,
                    struct cred *, caller_context_t *);
static int      socket_vop_read(struct vnode *, struct uio *, int,
                    struct cred *, caller_context_t *);
static int      socket_vop_write(struct vnode *, struct uio *, int,
                    struct cred *, caller_context_t *);
static int      socket_vop_ioctl(struct vnode *, int, intptr_t, int,
                    struct cred *, int32_t *, caller_context_t *);
static int      socket_vop_setfl(struct vnode *, int, int, cred_t *,
                    caller_context_t *);
static int      socket_vop_getattr(struct vnode *, struct vattr *, int,
                    struct cred *, caller_context_t *);
static int      socket_vop_setattr(struct vnode *, struct vattr *, int,
                    struct cred *, caller_context_t *);
static int      socket_vop_access(struct vnode *, int, int, struct cred *,
                    caller_context_t *);
static int      socket_vop_fsync(struct vnode *, int, struct cred *,
                    caller_context_t *);
static void     socket_vop_inactive(struct vnode *, struct cred *,
                    caller_context_t *);
static int      socket_vop_fid(struct vnode *, struct fid *,
                    caller_context_t *);
static int      socket_vop_seek(struct vnode *, offset_t, offset_t *,
                    caller_context_t *);
static int      socket_vop_poll(struct vnode *, short, int, short *,
                    struct pollhead **, caller_context_t *);

extern int      socket_close_internal(struct sonode *, int, cred_t *);
extern void     socket_destroy_internal(struct sonode *, cred_t *);

struct vnodeops *socket_vnodeops;
const fs_operation_def_t socket_vnodeops_template[] = {
        VOPNAME_OPEN,           { .vop_open = socket_vop_open },
        VOPNAME_CLOSE,          { .vop_close = socket_vop_close },
        VOPNAME_READ,           { .vop_read = socket_vop_read },
        VOPNAME_WRITE,          { .vop_write = socket_vop_write },
        VOPNAME_IOCTL,          { .vop_ioctl = socket_vop_ioctl },
        VOPNAME_SETFL,          { .vop_setfl = socket_vop_setfl },
        VOPNAME_GETATTR,        { .vop_getattr = socket_vop_getattr },
        VOPNAME_SETATTR,        { .vop_setattr = socket_vop_setattr },
        VOPNAME_ACCESS,         { .vop_access = socket_vop_access },
        VOPNAME_FSYNC,          { .vop_fsync = socket_vop_fsync },
        VOPNAME_INACTIVE,       { .vop_inactive = socket_vop_inactive },
        VOPNAME_FID,            { .vop_fid = socket_vop_fid },
        VOPNAME_SEEK,           { .vop_seek = socket_vop_seek },
        VOPNAME_POLL,           { .vop_poll = socket_vop_poll },
        VOPNAME_DISPOSE,        { .error = fs_error },
        NULL,                   NULL
};


/*
 * generic vnode ops
 */

/*ARGSUSED*/
static int
socket_vop_open(struct vnode **vpp, int flag, struct cred *cr,
    caller_context_t *ct)
{
        struct vnode *vp = *vpp;
        struct sonode *so = VTOSO(vp);

        flag &= ~FCREAT;                /* paranoia */
        mutex_enter(&so->so_lock);
        so->so_count++;
        mutex_exit(&so->so_lock);

        ASSERT(so->so_count != 0);      /* wraparound */
        ASSERT(vp->v_type == VSOCK);

        return (0);
}

/*ARGSUSED*/
static int
socket_vop_close(struct vnode *vp, int flag, int count, offset_t offset,
    struct cred *cr, caller_context_t *ct)
{
        struct sonode *so;
        int error = 0;

        so = VTOSO(vp);
        ASSERT(vp->v_type == VSOCK);

        cleanlocks(vp, ttoproc(curthread)->p_pid, 0);
        cleanshares(vp, ttoproc(curthread)->p_pid);

        if (vp->v_stream)
                strclean(vp);

        if (count > 1) {
                dprint(2, ("socket_vop_close: count %d\n", count));
                return (0);
        }

        mutex_enter(&so->so_lock);
        if (--so->so_count == 0) {
                /*
                 * Initiate connection shutdown.
                 */
                mutex_exit(&so->so_lock);
                error = socket_close_internal(so, flag, cr);
        } else {
                mutex_exit(&so->so_lock);
        }

        return (error);
}

/*ARGSUSED2*/
static int
socket_vop_read(struct vnode *vp, struct uio *uiop, int ioflag, struct cred *cr,
    caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);
        struct nmsghdr lmsg;

        ASSERT(vp->v_type == VSOCK);
        bzero((void *)&lmsg, sizeof (lmsg));

        return (socket_recvmsg(so, &lmsg, uiop, cr));
}

/*ARGSUSED2*/
static int
socket_vop_write(struct vnode *vp, struct uio *uiop, int ioflag,
    struct cred *cr, caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);
        struct nmsghdr lmsg;

        ASSERT(vp->v_type == VSOCK);
        bzero((void *)&lmsg, sizeof (lmsg));

        if (!(so->so_mode & SM_BYTESTREAM)) {
                /*
                 * If the socket is not byte stream set MSG_EOR
                 */
                lmsg.msg_flags = MSG_EOR;
        }

        return (socket_sendmsg(so, &lmsg, uiop, cr));
}

/*ARGSUSED4*/
static int
socket_vop_ioctl(struct vnode *vp, int cmd, intptr_t arg, int mode,
    struct cred *cr, int32_t *rvalp, caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);

        ASSERT(vp->v_type == VSOCK);

        return (socket_ioctl(so, cmd, arg, mode, cr, rvalp));
}

/*
 * Allow any flags. Record FNDELAY and FNONBLOCK so that they can be inherited
 * from listener to acceptor.
 */
/* ARGSUSED */
static int
socket_vop_setfl(vnode_t *vp, int oflags, int nflags, cred_t *cr,
    caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);
        int error = 0;

        ASSERT(vp->v_type == VSOCK);

        mutex_enter(&so->so_lock);
        if (nflags & FNDELAY)
                so->so_state |= SS_NDELAY;
        else
                so->so_state &= ~SS_NDELAY;
        if (nflags & FNONBLOCK)
                so->so_state |= SS_NONBLOCK;
        else
                so->so_state &= ~SS_NONBLOCK;
        mutex_exit(&so->so_lock);

        if (so->so_state & SS_ASYNC)
                oflags |= FASYNC;
        /*
         * Sets/clears the SS_ASYNC flag based on the presence/absence
         * of the FASYNC flag passed to fcntl(F_SETFL).
         * This exists solely for BSD fcntl() FASYNC compatibility.
         */
        if ((oflags ^ nflags) & FASYNC && so->so_version != SOV_STREAM) {
                int async = nflags & FASYNC;
                int32_t rv;

                /*
                 * For non-TPI sockets all we have to do is set/remove the
                 * SS_ASYNC bit, but for TPI it is more involved. For that
                 * reason we delegate the job to the protocol's ioctl handler.
                 */
                error = socket_ioctl(so, FIOASYNC, (intptr_t)&async, FKIOCTL,
                    cr, &rv);
        }
        return (error);
}


/*
 * Get the made up attributes for the vnode.
 * 4.3BSD returns the current time for all the timestamps.
 * 4.4BSD returns 0 for all the timestamps.
 * Here we use the access and modified times recorded in the sonode.
 *
 * Just like in BSD there is not effect on the underlying file system node
 * bound to an AF_UNIX pathname.
 *
 * When sockmod has been popped this will act just like a stream. Since
 * a socket is always a clone there is no need to inspect the attributes
 * of the "realvp".
 */
/* ARGSUSED */
int
socket_vop_getattr(struct vnode *vp, struct vattr *vap, int flags,
    struct cred *cr, caller_context_t *ct)
{
        dev_t           fsid;
        struct sonode   *so;
        static int      sonode_shift = 0;

        /*
         * Calculate the amount of bitshift to a sonode pointer which will
         * still keep it unique.  See below. Note that highbit() uses
         * 1-based indexing for the highest bit set (and 0 for 'no bits set').
         * To use the result of highbit() as a shift value, we must subtract 1
         * from the result.
         */
        if (sonode_shift == 0) {
                int bit = highbit(sizeof (struct sonode));

                /* Sanity check */
                VERIFY3S(bit, >, 0);
                sonode_shift = bit - 1;
        }

        so = VTOSO(vp);
        fsid = sockdev;

        if (so->so_version == SOV_STREAM) {
                /*
                 * The imaginary "sockmod" has been popped - act
                 * as a stream
                 */
                vap->va_type = VCHR;
                vap->va_mode = 0;
        } else {
                vap->va_type = vp->v_type;
                vap->va_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
                    S_IROTH|S_IWOTH;
        }
        vap->va_uid = vap->va_gid = 0;
        vap->va_fsid = fsid;
        /*
         * If the va_nodeid is > UINT32_MAX, then stat(2) might fail in
         * unexpected ways inside non-largefile aware 32-bit processes --
         * historically, socket inode values (va_nodeid values) were capped at
         * UINT16_MAX (for even more ancient reasons long since unnecessary).
         * To avoid the potential of surprise failures, we shift down
         * the sonode pointer address to try and get the most
         * uniqueness into 32-bits. In practice, this represents the unique
         * portion of the kernel address space, so the chance of duplicate
         * socket inode values is minimized.
         */
        vap->va_nodeid = ((ino_t)so >> sonode_shift) & 0xFFFFFFFF;
        vap->va_nlink = 0;
        vap->va_size = 0;

        /*
         * We need to zero out the va_rdev to avoid some fstats getting
         * EOVERFLOW.  This also mimics SunOS 4.x and BSD behavior.
         */
        vap->va_rdev = (dev_t)0;
        vap->va_blksize = MAXBSIZE;
        vap->va_nblocks = btod(vap->va_size);

        if (!SOCK_IS_NONSTR(so)) {
                sotpi_info_t *sti = SOTOTPI(so);

                mutex_enter(&so->so_lock);
                vap->va_atime.tv_sec = sti->sti_atime;
                vap->va_mtime.tv_sec = sti->sti_mtime;
                vap->va_ctime.tv_sec = sti->sti_ctime;
                mutex_exit(&so->so_lock);
        } else {
                vap->va_atime.tv_sec = 0;
                vap->va_mtime.tv_sec = 0;
                vap->va_ctime.tv_sec = 0;
        }

        vap->va_atime.tv_nsec = 0;
        vap->va_mtime.tv_nsec = 0;
        vap->va_ctime.tv_nsec = 0;
        vap->va_seq = 0;

        return (0);
}

/*
 * Set attributes.
 * Just like in BSD there is not effect on the underlying file system node
 * bound to an AF_UNIX pathname.
 *
 * When sockmod has been popped this will act just like a stream. Since
 * a socket is always a clone there is no need to modify the attributes
 * of the "realvp".
 */
/* ARGSUSED */
int
socket_vop_setattr(struct vnode *vp, struct vattr *vap, int flags,
    struct cred *cr, caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);

        /*
         * If times were changed, and we have a STREAMS socket, then update
         * the sonode.
         */
        if (!SOCK_IS_NONSTR(so)) {
                sotpi_info_t *sti = SOTOTPI(so);

                mutex_enter(&so->so_lock);
                if (vap->va_mask & AT_ATIME)
                        sti->sti_atime = vap->va_atime.tv_sec;
                if (vap->va_mask & AT_MTIME) {
                        sti->sti_mtime = vap->va_mtime.tv_sec;
                        sti->sti_ctime = gethrestime_sec();
                }
                mutex_exit(&so->so_lock);
        }

        return (0);
}

/*
 * Check if user is allowed to access vp. For non-STREAMS based sockets,
 * there might not be a device attached to the file system. So for those
 * types of sockets there are no permissions to check.
 *
 * XXX Should there be some other mechanism to check access rights?
 */
/*ARGSUSED*/
int
socket_vop_access(struct vnode *vp, int mode, int flags, struct cred *cr,
    caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);

        if (!SOCK_IS_NONSTR(so)) {
                ASSERT(so->so_sockparams->sp_sdev_info.sd_vnode != NULL);
                return (VOP_ACCESS(so->so_sockparams->sp_sdev_info.sd_vnode,
                    mode, flags, cr, NULL));
        }
        return (0);
}

/*
 * 4.3BSD and 4.4BSD fail a fsync on a socket with EINVAL.
 * This code does the same to be compatible and also to not give an
 * application the impression that the data has actually been "synced"
 * to the other end of the connection.
 */
/* ARGSUSED */
int
socket_vop_fsync(struct vnode *vp, int syncflag, struct cred *cr,
    caller_context_t *ct)
{
        return (EINVAL);
}

/*ARGSUSED*/
static void
socket_vop_inactive(struct vnode *vp, struct cred *cr, caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);

        ASSERT(vp->v_type == VSOCK);

        mutex_enter(&vp->v_lock);
        /*
         * If no one has reclaimed the vnode, remove from the
         * cache now.
         */
        if (vp->v_count < 1)
                cmn_err(CE_PANIC, "socket_inactive: Bad v_count");

        VN_RELE_LOCKED(vp);
        if (vp->v_count != 0) {
                mutex_exit(&vp->v_lock);
                return;
        }
        mutex_exit(&vp->v_lock);


        ASSERT(!vn_has_cached_data(vp));

        /* socket specfic clean-up */
        socket_destroy_internal(so, cr);
}

/* ARGSUSED */
int
socket_vop_fid(struct vnode *vp, struct fid *fidp, caller_context_t *ct)
{
        return (EINVAL);
}

/*
 * Sockets are not seekable.
 * (and there is a bug to fix STREAMS to make them fail this as well).
 */
/*ARGSUSED*/
int
socket_vop_seek(struct vnode *vp, offset_t ooff, offset_t *noffp,
    caller_context_t *ct)
{
        return (ESPIPE);
}

/*ARGSUSED*/
static int
socket_vop_poll(struct vnode *vp, short events, int anyyet, short *reventsp,
    struct pollhead **phpp, caller_context_t *ct)
{
        struct sonode *so = VTOSO(vp);

        ASSERT(vp->v_type == VSOCK);

        return (socket_poll(so, events, anyyet, reventsp, phpp));
}