/*      $NetBSD: puffs_rumpglue.c,v 1.16 2016/01/26 23:12:17 pooka Exp $        */

/*
 * Copyright (c) 2008 Antti Kantee.  All Rights Reserved.
 *
 * Development of this software was supported by the
 * Research Foundation of Helsinki University of Technology
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: puffs_rumpglue.c,v 1.16 2016/01/26 23:12:17 pooka Exp $");

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kthread.h>
#include <sys/mount.h>

#include <dev/putter/putter.h>
#include <dev/putter/putter_sys.h>

#include <rump-sys/vfs.h>

#include <rump/rump.h>
#include <rump/rumpuser.h>

void putterattach(void); /* XXX: from autoconf */
dev_type_open(puttercdopen);

struct ptargs {
        int comfd;
        int fpfd;
        struct filedesc *fdp;
};

#define BUFSIZE (64*1024)
extern int hz;

/*
 * Read requests from /dev/puffs and forward them to comfd
 *
 * XXX: the init detection is really sucky, but let's not
 * waste too much energy for a better one here
 */
static void
readthread(void *arg)
{
        struct ptargs *pap = arg;
        struct file *fp;
        register_t rv;
        char *buf;
        off_t off;
        int error, inited;

        buf = kmem_alloc(BUFSIZE, KM_SLEEP);
        inited = 0;

 retry:
        kpause(NULL, 0, hz/4, NULL);

        for (;;) {
                size_t n;

                off = 0;
                fp = fd_getfile(pap->fpfd);
                if (fp == NULL)
                        error = EINVAL;
                else
                        error = dofileread(pap->fpfd, fp, buf, BUFSIZE,
                            &off, 0, &rv);
                if (error) {
                        if (error == ENOENT && inited == 0)
                                goto retry;
                        if (error == ENXIO)
                                break;
                        panic("fileread failed: %d", error);
                }
                inited = 1;

                while (rv) {
                        struct rumpuser_iovec iov;

                        iov.iov_base = buf;
                        iov.iov_len = rv;

                        error = rumpuser_iovwrite(pap->comfd, &iov, 1,
                            RUMPUSER_IOV_NOSEEK, &n);
                        if (error)
                                panic("fileread failed: %d", error);
                        if (n == 0)
                                panic("fileread failed: closed");
                        rv -= n;
                }
        }

        kthread_exit(0);
}

/* Read requests from comfd and proxy them to /dev/puffs */
static void
writethread(void *arg)
{
        struct ptargs *pap = arg;
        struct file *fp;
        struct putter_hdr *phdr;
        register_t rv;
        char *buf;
        off_t off;
        size_t toread;
        int error;

        buf = kmem_alloc(BUFSIZE, KM_SLEEP);
        phdr = (struct putter_hdr *)buf;

        for (;;) {
                size_t n;

                /*
                 * Need to write everything to the "kernel" in one chunk,
                 * so make sure we have it here.
                 */
                off = 0;
                toread = sizeof(struct putter_hdr);
                do {
                        struct rumpuser_iovec iov;

                        iov.iov_base = buf+off;
                        iov.iov_len = toread;
                        error = rumpuser_iovread(pap->comfd, &iov, 1,
                            RUMPUSER_IOV_NOSEEK, &n);
                        if (error)
                                panic("rumpuser_read %zd %d", n, error);
                        if (n == 0)
                                goto out;
                        off += n;
                        if (off >= sizeof(struct putter_hdr))
                                toread = phdr->pth_framelen - off;
                        else
                                toread = off - sizeof(struct putter_hdr);
                } while (toread);

                off = 0;
                rv = 0;
                fp = fd_getfile(pap->fpfd);
                if (fp == NULL)
                        error = EINVAL;
                else
                        error = dofilewrite(pap->fpfd, fp, buf,
                            phdr->pth_framelen, &off, 0, &rv);
                if (error == ENXIO)
                        goto out;
                KASSERT(rv == phdr->pth_framelen);
        }
 out:

        kthread_exit(0);
}

int
rump_syspuffs_glueinit(int fd, int *newfd)
{
        struct ptargs *pap;
        int rv;

        if ((rv = rump_init()) != 0)
                return rv;

        putterattach();
        rv = puttercdopen(makedev(178, 0), 0, 0, curlwp);
        if (rv && rv != EMOVEFD)
                return rv;

        pap = kmem_alloc(sizeof(struct ptargs), KM_SLEEP);
        pap->comfd = fd;
        pap->fpfd = curlwp->l_dupfd;
        pap->fdp = curlwp->l_proc->p_fd;

        rv = kthread_create(PRI_NONE, 0, NULL, readthread, pap, NULL,
            "rputter");
        if (rv)
                return rv;

        rv = kthread_create(PRI_NONE, 0, NULL, writethread, pap, NULL,
            "wputter");
        if (rv)
                return rv;

        *newfd = curlwp->l_dupfd;
        return 0;
}