/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2002 Poul-Henning Kamp
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
 * and NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * 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. The names of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 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/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/bio.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/errno.h>
#include <sys/sbuf.h>
#include <sys/stdarg.h>
#include <geom/geom.h>
#include <geom/geom_slice.h>

static g_access_t g_slice_access;
static g_start_t g_slice_start;

static struct g_slicer *
g_slice_alloc(unsigned nslice, unsigned scsize)
{
        struct g_slicer *gsp;

        gsp = g_malloc(sizeof(*gsp), M_WAITOK | M_ZERO);
        if (scsize > 0)
                gsp->softc = g_malloc(scsize, M_WAITOK | M_ZERO);
        else
                gsp->softc = NULL;
        gsp->slices = g_malloc(nslice * sizeof(struct g_slice),
            M_WAITOK | M_ZERO);
        gsp->nslice = nslice;
        return (gsp);
}

static void
g_slice_free(struct g_geom *gp)
{
        struct g_slicer *gsp;

        gsp = gp->softc;
        gp->softc = NULL;

        /*
         * We can get multiple spoiled events before wither-washer
         * detaches our consumer, so this can get called multiple
         * times.
         */
        if (gsp == NULL)
                return;
        g_free(gsp->slices);
        g_free(gsp->hotspot);
        g_free(gsp->softc);
        g_free(gsp);
}

static int
g_slice_access(struct g_provider *pp, int dr, int dw, int de)
{
        int error;
        u_int u;
        struct g_geom *gp;
        struct g_consumer *cp;
        struct g_provider *pp2;
        struct g_slicer *gsp;
        struct g_slice *gsl, *gsl2;

        gp = pp->geom;
        cp = LIST_FIRST(&gp->consumer);
        KASSERT (cp != NULL, ("g_slice_access but no consumer"));
        gsp = gp->softc;
        if (dr > 0 || dw > 0 || de > 0) {
                gsl = &gsp->slices[pp->index];
                for (u = 0; u < gsp->nslice; u++) {
                        gsl2 = &gsp->slices[u];
                        if (gsl2->length == 0)
                                continue;
                        if (u == pp->index)
                                continue;
                        if (gsl->offset + gsl->length <= gsl2->offset)
                                continue;
                        if (gsl2->offset + gsl2->length <= gsl->offset)
                                continue;
                        /* overlap */
                        pp2 = gsl2->provider;
                        if ((pp->acw + dw) > 0 && pp2->ace > 0)
                                return (EPERM);
                        if ((pp->ace + de) > 0 && pp2->acw > 0)
                                return (EPERM);
                }
        }
        /* On first open, grab an extra "exclusive" bit */
        if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
                de++;
        /* ... and let go of it on last close */
        if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
                de--;
        error = g_access(cp, dr, dw, de);

        /*
         * Free the softc if all providers have been closed and this geom
         * is being removed.
         */
        if (error == 0 && (gp->flags & G_GEOM_WITHER) != 0 &&
            (cp->acr + cp->acw + cp->ace) == 0)
                g_slice_free(gp);

        return (error);
}

/*
 * XXX: It should be possible to specify here if we should finish all of the
 * XXX: bio, or only the non-hot bits.  This would get messy if there were
 * XXX: two hot spots in the same bio, so for now we simply finish off the
 * XXX: entire bio.  Modifying hot data on the way to disk is frowned on
 * XXX: so making that considerably harder is not a bad idea anyway.
 */
void
g_slice_finish_hot(struct bio *bp)
{
        struct bio *bp2;
        struct g_geom *gp;
        struct g_consumer *cp;
        struct g_slicer *gsp;
        struct g_slice *gsl;
        int idx;

        KASSERT(bp->bio_to != NULL,
            ("NULL bio_to in g_slice_finish_hot(%p)", bp));
        KASSERT(bp->bio_from != NULL,
            ("NULL bio_from in g_slice_finish_hot(%p)", bp));
        gp = bp->bio_to->geom;
        gsp = gp->softc;
        cp = LIST_FIRST(&gp->consumer);
        KASSERT(cp != NULL, ("NULL consumer in g_slice_finish_hot(%p)", bp));
        idx = bp->bio_to->index;
        gsl = &gsp->slices[idx];

        bp2 = g_clone_bio(bp);
        if (bp2 == NULL) {
                g_io_deliver(bp, ENOMEM);
                return;
        }
        if (bp2->bio_offset + bp2->bio_length > gsl->length)
                bp2->bio_length = gsl->length - bp2->bio_offset;
        bp2->bio_done = g_std_done;
        bp2->bio_offset += gsl->offset;
        g_io_request(bp2, cp);
        return;
}

static void
g_slice_done(struct bio *bp)
{

        KASSERT(bp->bio_cmd == BIO_GETATTR &&
            strcmp(bp->bio_attribute, "GEOM::ident") == 0,
            ("bio_cmd=0x%x bio_attribute=%s", bp->bio_cmd, bp->bio_attribute));

        if (bp->bio_error == 0 && bp->bio_data[0] != '\0') {
                char idx[8];

                /* Add index to the ident received. */
                snprintf(idx, sizeof(idx), "s%d",
                    bp->bio_parent->bio_to->index);
                if (strlcat(bp->bio_data, idx, bp->bio_length) >=
                    bp->bio_length) {
                        bp->bio_error = EFAULT;
                }
        }
        g_std_done(bp);
}

static void
g_slice_start(struct bio *bp)
{
        struct bio *bp2;
        struct g_provider *pp;
        struct g_geom *gp;
        struct g_consumer *cp;
        struct g_slicer *gsp;
        struct g_slice *gsl;
        struct g_slice_hot *ghp;
        int idx, error;
        u_int m_index;
        off_t t;

        pp = bp->bio_to;
        gp = pp->geom;
        gsp = gp->softc;
        cp = LIST_FIRST(&gp->consumer);
        idx = pp->index;
        gsl = &gsp->slices[idx];
        switch(bp->bio_cmd) {
        case BIO_READ:
        case BIO_WRITE:
        case BIO_DELETE:
                if (bp->bio_offset > gsl->length) {
                        g_io_deliver(bp, EINVAL); /* XXX: EWHAT ? */
                        return;
                }
                /*
                 * Check if we collide with any hot spaces, and call the
                 * method once if so.
                 */
                t = bp->bio_offset + gsl->offset;
                for (m_index = 0; m_index < gsp->nhotspot; m_index++) {
                        ghp = &gsp->hotspot[m_index];
                        if (t >= ghp->offset + ghp->length)
                                continue;
                        if (t + bp->bio_length <= ghp->offset)
                                continue;
                        switch(bp->bio_cmd) {
                        case BIO_READ:          idx = ghp->ract; break;
                        case BIO_WRITE:         idx = ghp->wact; break;
                        case BIO_DELETE:        idx = ghp->dact; break;
                        }
                        switch(idx) {
                        case G_SLICE_HOT_ALLOW:
                                /* Fall out and continue normal processing */
                                continue;
                        case G_SLICE_HOT_DENY:
                                g_io_deliver(bp, EROFS);
                                return;
                        case G_SLICE_HOT_START:
                                error = gsp->start(bp);
                                if (error && error != EJUSTRETURN)
                                        g_io_deliver(bp, error);
                                return;
                        case G_SLICE_HOT_CALL:
                                error = g_post_event(gsp->hot, bp, M_NOWAIT,
                                    gp, NULL);
                                if (error)
                                        g_io_deliver(bp, error);
                                return;
                        }
                        break;
                }
                bp2 = g_clone_bio(bp);
                if (bp2 == NULL) {
                        g_io_deliver(bp, ENOMEM);
                        return;
                }
                if (bp2->bio_offset + bp2->bio_length > gsl->length)
                        bp2->bio_length = gsl->length - bp2->bio_offset;
                bp2->bio_done = g_std_done;
                bp2->bio_offset += gsl->offset;
                g_io_request(bp2, cp);
                return;
        case BIO_GETATTR:
                /* Give the real method a chance to override */
                if (gsp->start != NULL && gsp->start(bp))
                        return;
                if (!strcmp("GEOM::ident", bp->bio_attribute)) {
                        bp2 = g_clone_bio(bp);
                        if (bp2 == NULL) {
                                g_io_deliver(bp, ENOMEM);
                                return;
                        }
                        bp2->bio_done = g_slice_done;
                        g_io_request(bp2, cp);
                        return;
                }
                if (!strcmp("GEOM::kerneldump", bp->bio_attribute)) {
                        struct g_kerneldump *gkd;

                        gkd = (struct g_kerneldump *)bp->bio_data;
                        gkd->offset += gsp->slices[idx].offset;
                        if (gkd->length > gsp->slices[idx].length)
                                gkd->length = gsp->slices[idx].length;
                        /* now, pass it on downwards... */
                }
                /* FALLTHROUGH */
        case BIO_SPEEDUP:
        case BIO_FLUSH:
                bp2 = g_clone_bio(bp);
                if (bp2 == NULL) {
                        g_io_deliver(bp, ENOMEM);
                        return;
                }
                bp2->bio_done = g_std_done;
                g_io_request(bp2, cp);
                break;
        default:
                g_io_deliver(bp, EOPNOTSUPP);
                return;
        }
}

void
g_slice_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
{
        struct g_slicer *gsp;

        gsp = gp->softc;
        if (indent == NULL) {
                sbuf_printf(sb, " i %u", pp->index);
                sbuf_printf(sb, " o %ju", 
                    (uintmax_t)gsp->slices[pp->index].offset);
                return;
        }
        if (pp != NULL) {
                sbuf_printf(sb, "%s<index>%u</index>\n", indent, pp->index);
                sbuf_printf(sb, "%s<length>%ju</length>\n",
                    indent, (uintmax_t)gsp->slices[pp->index].length);
                sbuf_printf(sb, "%s<seclength>%ju</seclength>\n", indent,
                    (uintmax_t)gsp->slices[pp->index].length / 512);
                sbuf_printf(sb, "%s<offset>%ju</offset>\n", indent,
                    (uintmax_t)gsp->slices[pp->index].offset);
                sbuf_printf(sb, "%s<secoffset>%ju</secoffset>\n", indent,
                    (uintmax_t)gsp->slices[pp->index].offset / 512);
        }
}

int
g_slice_config(struct g_geom *gp, u_int idx, int how, off_t offset, off_t length, u_int sectorsize, const char *fmt, ...)
{
        struct g_provider *pp, *pp2;
        struct g_slicer *gsp;
        struct g_slice *gsl;
        va_list ap;
        struct sbuf *sb;
        int acc;

        g_trace(G_T_TOPOLOGY, "g_slice_config(%s, %d, %d)",
             gp->name, idx, how);
        g_topology_assert();
        gsp = gp->softc;
        if (idx >= gsp->nslice)
                return(EINVAL);
        gsl = &gsp->slices[idx];
        pp = gsl->provider;
        if (pp != NULL)
                acc = pp->acr + pp->acw + pp->ace;
        else
                acc = 0;
        if (acc != 0 && how != G_SLICE_CONFIG_FORCE) {
                if (length < gsl->length)
                        return(EBUSY);
                if (offset != gsl->offset)
                        return(EBUSY);
        }
        /* XXX: check offset + length <= MEDIASIZE */
        if (how == G_SLICE_CONFIG_CHECK)
                return (0);
        gsl->length = length;
        gsl->offset = offset;
        gsl->sectorsize = sectorsize;
        if (length == 0) {
                if (pp == NULL)
                        return (0);
                if (bootverbose)
                        printf("GEOM: Deconfigure %s\n", pp->name);
                g_wither_provider(pp, ENXIO);
                gsl->provider = NULL;
                gsp->nprovider--;
                return (0);
        }
        if (pp != NULL) {
                if (bootverbose)
                        printf("GEOM: Reconfigure %s, start %jd length %jd end %jd\n",
                            pp->name, (intmax_t)offset, (intmax_t)length,
                            (intmax_t)(offset + length - 1));
                g_resize_provider(pp, gsl->length);
                return (0);
        }
        sb = sbuf_new_auto();
        va_start(ap, fmt);
        sbuf_vprintf(sb, fmt, ap);
        va_end(ap);
        sbuf_finish(sb);
        pp = g_new_providerf(gp, "%s", sbuf_data(sb));
        pp2 = LIST_FIRST(&gp->consumer)->provider;
        pp->stripesize = pp2->stripesize;
        pp->stripeoffset = pp2->stripeoffset + offset;
        if (pp->stripesize > 0)
                pp->stripeoffset %= pp->stripesize;
        if (gsp->nhotspot == 0) {
                pp->flags |= pp2->flags & G_PF_ACCEPT_UNMAPPED;
                pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
        }
        if (0 && bootverbose)
                printf("GEOM: Configure %s, start %jd length %jd end %jd\n",
                    pp->name, (intmax_t)offset, (intmax_t)length,
                    (intmax_t)(offset + length - 1));
        pp->index = idx;
        pp->mediasize = gsl->length;
        pp->sectorsize = gsl->sectorsize;
        gsl->provider = pp;
        gsp->nprovider++;
        g_error_provider(pp, 0);
        sbuf_delete(sb);
        return(0);
}

/*
 * Configure "hotspots".  A hotspot is a piece of the parent device which
 * this particular slicer cares about for some reason.  Typically because
 * it contains meta-data used to configure the slicer.
 * A hotspot is identified by its index number. The offset and length are
 * relative to the parent device, and the three "?act" fields specify
 * what action to take on BIO_READ, BIO_DELETE and BIO_WRITE.
 *
 * XXX: There may be a race relative to g_slice_start() here, if an existing
 * XXX: hotspot is changed wile I/O is happening.  Should this become a problem
 * XXX: we can protect the hotspot stuff with a mutex.
 */

int
g_slice_conf_hot(struct g_geom *gp, u_int idx, off_t offset, off_t length, int ract, int dact, int wact)
{
        struct g_slicer *gsp;
        struct g_slice_hot *gsl, *gsl2;
        struct g_consumer *cp;
        struct g_provider *pp;

        g_trace(G_T_TOPOLOGY, "g_slice_conf_hot(%s, idx: %d, off: %jd, len: %jd)",
            gp->name, idx, (intmax_t)offset, (intmax_t)length);
        g_topology_assert();
        gsp = gp->softc;
        /* Deny unmapped I/O and direct dispatch if hotspots are used. */
        if (gsp->nhotspot == 0) {
                LIST_FOREACH(pp, &gp->provider, provider)
                        pp->flags &= ~(G_PF_ACCEPT_UNMAPPED |
                            G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE);
                LIST_FOREACH(cp, &gp->consumer, consumer)
                        cp->flags &= ~(G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE);
        }
        gsl = gsp->hotspot;
        if(idx >= gsp->nhotspot) {
                gsl2 = g_malloc((idx + 1) * sizeof(*gsl2), M_WAITOK | M_ZERO);
                if (gsp->hotspot != NULL)
                        bcopy(gsp->hotspot, gsl2, gsp->nhotspot * sizeof(*gsl2));
                gsp->hotspot = gsl2;
                if (gsp->hotspot != NULL)
                        g_free(gsl);
                gsl = gsl2;
                gsp->nhotspot = idx + 1;
        }
        gsl[idx].offset = offset;
        gsl[idx].length = length;
        KASSERT(!((ract | dact | wact) & G_SLICE_HOT_START)
            || gsp->start != NULL, ("G_SLICE_HOT_START but no slice->start"));
        /* XXX: check that we _have_ a start function if HOT_START specified */
        gsl[idx].ract = ract;
        gsl[idx].dact = dact;
        gsl[idx].wact = wact;
        return (0);
}

void
g_slice_orphan(struct g_consumer *cp)
{
        struct g_geom *gp;

        g_topology_assert();
        gp = cp->geom;
        g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp, gp->name);
        g_wither_geom(gp, ENXIO);

        /*
         * We can safely free the softc now if there are no accesses,
         * otherwise g_slice_access() will do that after the last close.
         */
        if ((cp->acr + cp->acw + cp->ace) == 0)
                g_slice_free(gp);
}

void
g_slice_spoiled(struct g_consumer *cp)
{

        g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp, cp->geom->name);
        cp->flags |= G_CF_ORPHAN;
        g_slice_orphan(cp);
}

int
g_slice_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
{

        g_slice_spoiled(LIST_FIRST(&gp->consumer));
        return (0);
}

struct g_geom *
g_slice_new(struct g_class *mp, u_int slices, struct g_provider *pp, struct g_consumer **cpp, void *extrap, int extra, g_slice_start_t *start)
{
        struct g_geom *gp;
        struct g_slicer *gsp;
        struct g_consumer *cp;
        void **vp;
        int error;

        g_topology_assert();
        vp = (void **)extrap;
        gp = g_new_geom(mp, pp->name);
        gsp = g_slice_alloc(slices, extra);
        gsp->start = start;
        gp->softc = gsp;
        gp->start = g_slice_start;
        gp->access = g_slice_access;
        gp->orphan = g_slice_orphan;
        gp->spoiled = g_slice_spoiled;
        if (gp->dumpconf == NULL)
                gp->dumpconf = g_slice_dumpconf;
        if (gp->class->destroy_geom == NULL)
                gp->class->destroy_geom = g_slice_destroy_geom;
        cp = g_new_consumer(gp);
        cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
        error = g_attach(cp, pp);
        if (error == 0)
                error = g_access(cp, 1, 0, 0);
        if (error) {
                g_wither_geom(gp, ENXIO);
                return (NULL);
        }
        if (extrap != NULL)
                *vp = gsp->softc;
        *cpp = cp;
        return (gp);
}