/*      $NetBSD: subr.c,v 1.8 2020/05/26 19:38:14 uwe Exp $     */

/*
 * Copyright (c) 2007  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.
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: subr.c,v 1.8 2020/05/26 19:38:14 uwe Exp $");
#endif /* !lint */

#include <sys/types.h>

#include <errno.h>
#include <puffs.h>
#include <stdlib.h>
#include <util.h>

#include "ninepuffs.h"
#include "nineproto.h"

void
qid2vattr(struct vattr *vap, const struct qid9p *qid)
{

        vap->va_fileid = qid->qidpath;
        vap->va_gen = qid->qidvers;
        if (qid->qidtype & P9PROTO_QID_TYPE_DIR)
                vap->va_type = VDIR;
        else
                vap->va_type = VREG;
}

static struct puffs_node *
makep9pnode(struct puffs_usermount *pu, p9pfid_t fid)
{
        struct p9pnode *p9n;
        struct puffs_node *pn;

        p9n = emalloc(sizeof(struct p9pnode));
        memset(p9n, 0, sizeof(struct p9pnode));
        p9n->fid_base = fid;
        LIST_INIT(&p9n->dir_openlist);

        pn = puffs_pn_new(pu, p9n);
        if (pn == NULL)
                abort();

        return pn;
}

struct puffs_node *
newp9pnode_va(struct puffs_usermount *pu, const struct vattr *va, p9pfid_t fid)
{
        struct puffs_node *pn;

        pn = makep9pnode(pu, fid);
        pn->pn_va = *va;

        return pn;
}

struct puffs_node *
newp9pnode_qid(struct puffs_usermount *pu, const struct qid9p *qid,
        p9pfid_t fid)
{
        struct puffs_node *pn;

        pn = makep9pnode(pu, fid);
        puffs_vattr_null(&pn->pn_va);
        qid2vattr(&pn->pn_va, qid);

        return pn;
}

/*
 * search list of fids, or if none is found, walk a fid for a new one
 * and issue dummy readdirs until we get the result we want
 */
int
getdfwithoffset(struct puffs_usermount *pu, struct p9pnode *p9n, off_t wantoff,
        struct dirfid **rfid)
{
        struct puffs_cc *pcc = puffs_cc_getcc(pu);
        struct puffs9p *p9p = puffs_getspecific(pu);
        struct dirfid *dfp = NULL;
        int rv;

        LIST_FOREACH(dfp, &p9n->dir_openlist, entries) {
                if (dfp->seekoff == wantoff) {
                        LIST_REMOVE(dfp, entries);
                        *rfid = dfp;
                        return 0;
                }
        }

        /* didn't get off easy?  damn, do manual labour */
        dfp = ecalloc(1, sizeof(struct dirfid));
        dfp->fid = NEXTFID(p9p);
        rv = proto_cc_open(pu, p9n->fid_base, dfp->fid, P9PROTO_OMODE_READ);
        if (rv)
                goto out;

        off_t curoff = 0;
        if (wantoff != 0) {
                struct puffs_framebuf *pb = p9pbuf_makeout();
                for (;;) {
                        off_t advance = wantoff - curoff;

                        p9ptag_t tag = NEXTTAG(p9p);
                        p9pbuf_put_1(pb, P9PROTO_T_READ);
                        p9pbuf_put_2(pb, tag);
                        p9pbuf_put_4(pb, dfp->fid);
                        p9pbuf_put_8(pb, curoff);
                        p9pbuf_put_4(pb, advance);
                        GETRESPONSE(pb);

                        if (p9pbuf_get_type(pb) != P9PROTO_R_READ) {
                                rv = proto_handle_rerror(pu, pb);
                                puffs_framebuf_destroy(pb);
                                goto out;
                        }

                        /*
                         * Check how many bytes we got.  If we got the
                         * amount we wanted, we are at the correct position.
                         * If we got zero bytes, either the directory
                         * doesn't "support" the seek offset we want
                         * (someone has probably inserted an entry
                         * meantime) or we at the end of directory.
                         * Either way, let the upper layer deal with it.
                         */
                        uint32_t count;
                        p9pbuf_get_4(pb, &count);
                        curoff += count;
                        if (count == advance || count == 0)
                                break;

                        p9pbuf_recycleout(pb);
                }
                puffs_framebuf_destroy(pb);
        }

        dfp->seekoff = curoff;
        *rfid = dfp;
        return 0;

 out:
        free(dfp);
        return rv;
}

void
releasedf(struct puffs_usermount *pu, struct dirfid *dfp)
{

        proto_cc_clunkfid(pu, dfp->fid, 0);
        free(dfp);
}

void
storedf(struct p9pnode *p9n, struct dirfid *dfp)
{

        LIST_INSERT_HEAD(&p9n->dir_openlist, dfp, entries);
}

void
nukealldf(struct puffs_usermount *pu, struct p9pnode *p9n)
{
        struct dirfid *dfp;

        while ((dfp = LIST_FIRST(&p9n->dir_openlist)) != NULL) {
                LIST_REMOVE(dfp, entries);
                releasedf(pu, dfp);
        }
}