/*      $NetBSD: umserv.c,v 1.3 2016/01/25 11:45:58 pooka Exp $ */

/*
 * Copyright (c) 2009 Antti Kantee.  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.
 *
 * 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.
 */

/*
 * This is a [quick, simple & dirty] userspace sd@umass server.
 * We probe USB devices using rump and attach them to the host kernel
 * using pud(4).  The resulting block devices can be e.g. read
 * and/or mounted.
 *
 * Since there is no devfs support in NetBSD, we create crudo & cotto
 * device nodes in the current directory.  Operating on these in the
 * host OS will direct operations to this userspace server, e.g.:
 *   golem> disklabel ./rumpsd0d
 *   golem> mount_msdos ./rumpsd0e /mnt
 * will cause file system access to /mnt be backed by the umass server
 * in userspace.  Due to the relatively experimental nature of this
 * server, rump file servers are recommended for mounting experiments.
 */

#include <sys/types.h>
#include <sys/syslimits.h>

#include <dev/pud/pud_msgif.h>

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

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/*
 * No devfs?  No problem.  We just hack a bit & wait for the dust to settle.
 */
#define NODEBASE "rumpsd0"
#define MYMAJOR 411
static int
makenodes(void)
{
        char path[PATH_MAX];
        struct stat sb;
        int i, j, rv;

        for (i = 0; i < 2; i++) {
                int minnum = 0;

                for (j = 0; j < 8; j++, minnum++) {
                        sprintf(path, "%s%s%c",
                            i == 0 ? "" : "r", NODEBASE, minnum + 'a');
                        if (stat(path, &sb) == 0)
                                continue;
                        rv = mknod(path, (i == 0 ? S_IFBLK : S_IFCHR) | 0666,
                            makedev(MYMAJOR, minnum));
                        if (rv != 0 && !(rv == -1 && errno == EEXIST))
                                return rv;
                }
        }

        return 0;
}

int
main(int argc, char *argv[])
{
        char path[PATH_MAX];
        struct pud_conf_reg pcr;
        struct pud_req *pdr;
        struct vnode *devvps[8], *devvp;
        kauth_cred_t rootcred;
        ssize_t n;
        int fd, rv, i;

        if (makenodes() == -1)
                err(1, "makenodes");

        fd = open(_PATH_PUD, O_RDWR);
        if (fd == -1)
                err(1, "open");

#define PDRSIZE (64*1024+1024)
        pdr = malloc(PDRSIZE);
        if (pdr == NULL)
                err(1, "malloc");

        memset(&pcr, 0, sizeof(pcr));
        pcr.pm_pdr.pdr_pth.pth_framelen = sizeof(struct pud_conf_reg);
        pcr.pm_version = PUD_DEVELVERSION | PUD_VERSION;
        pcr.pm_pdr.pdr_reqclass = PUD_REQ_CONF;
        pcr.pm_pdr.pdr_reqtype = PUD_CONF_REG;

        pcr.pm_regdev = makedev(MYMAJOR, 0);
        pcr.pm_flags = PUD_CONFFLAG_BDEV;
        strlcpy(pcr.pm_devname, "youmass", sizeof(pcr.pm_devname));

        n = write(fd, &pcr, pcr.pm_pdr.pdr_pth.pth_framelen);
        if (n == -1)
                err(1, "configure"); /* XXX: doubles as protocol error */

        rump_boot_sethowto(RUMP_AB_VERBOSE);
        rump_init();

        /*
         * We use the raw devices.  This avoids undesired block caching
         * in read/write.  It's also simpler.  It's even mostly correct.
         *
         * As is probably obvious by now, we execute ops through specfs.
         * Why?  Can't say it wasn't because specfs-via-vnodes was
         * already supported by rump.  But, that's mostly how the
         * kernel does it (cf. mounting file system etc).
         */
        for (i = 0; i < 8; i++) {
                sprintf(path, "/dev/rsd0%c", 'a' + i);
                if ((rv = rump_pub_namei(RUMP_NAMEI_LOOKUP, 0, path,
                    NULL, &devvps[i], NULL)) != 0)
                        errx(1, "raw device lookup failed %d", rv);
        }

        rootcred = rump_pub_cred_create(0, 0, 0, NULL);

        /* process requests ad infinitum */
        for (;;) {
                struct pud_creq_open *pr_open;
                struct pud_creq_close *pr_close;
                struct pud_req_readwrite *pr_rw;
                struct pud_req_ioctl *pr_ioctl;
                struct uio *uio;
                size_t reslen;
                int minordev;

                n = read(fd, pdr, PDRSIZE);
                if (n == -1)
                        err(1, "read");

                minordev = minor(pdr->pdr_dev);
                if (minordev < 0 || minordev >= 8) {
                        rv = ENXIO;
                        goto sendresponse;
                }
                devvp = devvps[minordev];

                switch (pdr->pdr_reqtype) {
                case PUD_BDEV_OPEN:
                        pr_open = (void *)pdr;
                        RUMP_VOP_LOCK(devvp, RUMP_LK_EXCLUSIVE);
                        rv = RUMP_VOP_OPEN(devvp, pr_open->pm_fmt, rootcred);
                        RUMP_VOP_UNLOCK(devvp);
                        break;

                case PUD_BDEV_CLOSE:
                        pr_close = (void *)pdr;
                        RUMP_VOP_LOCK(devvp, RUMP_LK_EXCLUSIVE);
                        rv = RUMP_VOP_CLOSE(devvp, pr_close->pm_fmt, rootcred);
                        RUMP_VOP_UNLOCK(devvp);
                        break;

                case PUD_BDEV_IOCTL:
                        pr_ioctl = (void *)pdr;
                        rv = RUMP_VOP_IOCTL(devvp, pr_ioctl->pm_iocmd,
                            pr_ioctl->pm_data, pr_ioctl->pm_flag, rootcred);
                        break;

                case PUD_BDEV_STRATREAD:
                        pr_rw = (void *)pdr;
                        assert(pr_rw->pm_resid <= 64*1024);
                        uio = rump_pub_uio_setup(&pr_rw->pm_data[0],
                            pr_rw->pm_resid, pr_rw->pm_offset, RUMPUIO_READ);
                        RUMP_VOP_LOCK(devvp, RUMP_LK_SHARED);
                        rv = RUMP_VOP_READ(devvp, uio, 0, rootcred);
                        RUMP_VOP_UNLOCK(devvp);
                        reslen = rump_pub_uio_free(uio);
                        pdr->pdr_pth.pth_framelen -= reslen;
                        pr_rw->pm_resid = reslen;
                        break;

                case PUD_BDEV_STRATWRITE:
                        pr_rw = (void *)pdr;
                        uio = rump_pub_uio_setup(&pr_rw->pm_data[0],
                            pr_rw->pm_resid, pr_rw->pm_offset, RUMPUIO_WRITE);
                        RUMP_VOP_LOCK(devvp, RUMP_LK_EXCLUSIVE);
                        rv = RUMP_VOP_WRITE(devvp, uio, 0, rootcred);
                        RUMP_VOP_UNLOCK(devvp);
                        reslen = rump_pub_uio_free(uio);
                        pr_rw->pm_resid = reslen;
                        pdr->pdr_pth.pth_framelen=sizeof(struct pud_creq_write);
                        rv = 0;
                        break;

                }

 sendresponse:
                pdr->pdr_rv = rv;
                n = write(fd, pdr, pdr->pdr_pth.pth_framelen);
                assert(n == (ssize_t)pdr->pdr_pth.pth_framelen);
        }
}