/*      $NetBSD: node.c,v 1.66 2021/09/16 21:29:42 andvar Exp $ */

/*
* Copyright (c) 2006-2009  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.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: node.c,v 1.66 2021/09/16 21:29:42 andvar Exp $");
#endif /* !lint */

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#include "psshfs.h"
#include "sftp_proto.h"

int
psshfs_node_lookup(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct puffs_newinfo *pni, const struct puffs_cn *pcn)
{
       struct psshfs_ctx *pctx = puffs_getspecific(pu);
       struct puffs_node *pn_dir = opc;
       struct psshfs_node *psn, *psn_dir = pn_dir->pn_data;
       struct puffs_node *pn;
       struct psshfs_dir *pd;
       struct vattr va;
       int rv;

       if (PCNISDOTDOT(pcn)) {
               psn = psn_dir->parent->pn_data;
               psn->stat &= ~PSN_RECLAIMED;

               puffs_newinfo_setcookie(pni, psn_dir->parent);
               puffs_newinfo_setvtype(pni, VDIR);
               return 0;
       }

       rv = sftp_readdir(pu, pctx, pn_dir);
       if (rv) {
               if (rv != EPERM)
                       return rv;

               /*
                * Can't read the directory.  We still might be
                * able to find the node with getattr in -r+x dirs
                */
               rv = getpathattr(pu, PCNPATH(pcn), &va);
               if (rv)
                       return rv;

               /* guess */
               if (va.va_type == VDIR)
                       va.va_nlink = 2;
               else
                       va.va_nlink = 1;

               pn = allocnode(pu, pn_dir, pcn->pcn_name, &va);
               psn = pn->pn_data;
               psn->attrread = time(NULL);
       } else {
               pd = lookup(psn_dir->dir, psn_dir->dentnext, pcn->pcn_name);
               if (!pd) {
                       return ENOENT;
               }

               if (pd->entry)
                       pn = pd->entry;
               else
                       pd->entry = pn = makenode(pu, pn_dir, pd, &pd->va);

               /*
                * sure sure we have fresh attributes.  most likely we will
                * have them cached.  we might not if we go through:
                * create - reclaim - lookup (this).
                */
               rv = getnodeattr(pu, pn, PCNPATH(pcn));
               if (rv)
                       return rv;

               psn = pn->pn_data;
       }

       psn->stat &= ~PSN_RECLAIMED;

       puffs_newinfo_setcookie(pni, pn);
       puffs_newinfo_setvtype(pni, pn->pn_va.va_type);
       puffs_newinfo_setsize(pni, pn->pn_va.va_size);

       return 0;
}

int
psshfs_node_getattr(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct vattr *vap, const struct puffs_cred *pcr)
{
       struct puffs_node *pn = opc;
       int rv;

       rv = getnodeattr(pu, pn, NULL);
       if (rv)
               return rv;

       memcpy(vap, &pn->pn_va, sizeof(struct vattr));

       return 0;
}

int
psshfs_node_setattr(struct puffs_usermount *pu, puffs_cookie_t opc,
       const struct vattr *va, const struct puffs_cred *pcr)
{
       struct puffs_cc *pcc = puffs_cc_getcc(pu);
       struct psshfs_ctx *pctx = puffs_getspecific(pu);
       uint32_t reqid;
       struct puffs_framebuf *pb;
       struct vattr kludgeva;
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       int rv;

       /*
        * If we cached the remote attributes recently enough, and this
        * setattr operation would change nothing that sftp actually
        * records, then we can skip the sftp request.  So first check
        * whether we have the attributes cached, and then compare
        * every field that we might send to the sftp server.
        */

       if (!psn->attrread || REFRESHTIMEOUT(pctx, time(NULL)-psn->attrread))
               goto setattr;

#define CHECK(FIELD, TYPE) do {                                         \
       if ((va->FIELD != (TYPE)PUFFS_VNOVAL) &&                        \
           (va->FIELD != pn->pn_va.FIELD))                             \
               goto setattr;                                           \
} while (0)

#define CHECKID(FIELD, TYPE, DOMANGLE, MINE, MANGLED) do {              \
       if ((va->FIELD != (TYPE)PUFFS_VNOVAL) &&                        \
           (pn->pn_va.FIELD !=                                         \
               ((pctx->DOMANGLE && (va->FIELD == pctx->MINE))          \
                   ? pctx->MANGLED                                     \
                   : va->FIELD)))                                      \
               goto setattr;                                           \
} while (0)

       CHECK(va_size, uint64_t);
       CHECKID(va_uid, uid_t, domangleuid, myuid, mangleuid);
       CHECKID(va_gid, gid_t, domanglegid, mygid, manglegid);
       CHECK(va_mode, mode_t);
       CHECK(va_atime.tv_sec, time_t);
       CHECK(va_mtime.tv_sec, time_t);

       /* Nothing to change.  */
       return 0;

#undef CHECK
#undef CHECKID

setattr:
       reqid = NEXTREQ(pctx);
       pb = psbuf_makeout();

       psbuf_req_str(pb, SSH_FXP_SETSTAT, reqid, PNPATH(pn));

       memcpy(&kludgeva, va, sizeof(struct vattr));

       /* XXX: kludge due to openssh server implementation */
       if (va->va_atime.tv_sec != PUFFS_VNOVAL
           && va->va_mtime.tv_sec == PUFFS_VNOVAL) {
               if (pn->pn_va.va_mtime.tv_sec != PUFFS_VNOVAL)
                       kludgeva.va_mtime.tv_sec = pn->pn_va.va_mtime.tv_sec;
               else
                       kludgeva.va_mtime.tv_sec = va->va_atime.tv_sec;
       }
       if (va->va_mtime.tv_sec != PUFFS_VNOVAL
           && va->va_atime.tv_sec == PUFFS_VNOVAL) {
               if (pn->pn_va.va_atime.tv_sec != PUFFS_VNOVAL)
                       kludgeva.va_atime.tv_sec = pn->pn_va.va_atime.tv_sec;
               else
                       kludgeva.va_atime.tv_sec = va->va_mtime.tv_sec;
       }

       psbuf_put_vattr(pb, &kludgeva, pctx);
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_status(pb);
       if (rv == 0) {
               puffs_setvattr(&pn->pn_va, &kludgeva);
               psn->attrread = time(NULL);
       }

out:
       puffs_framebuf_destroy(pb);
       return rv;
}

int
psshfs_node_create(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct puffs_newinfo *pni, const struct puffs_cn *pcn,
       const struct vattr *va)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn = opc;
       struct puffs_node *pn_new;
       char *fhand = NULL;
       uint32_t fhandlen;

       /* Create node on server first */
       psbuf_req_str(pb, SSH_FXP_OPEN, reqid, PCNPATH(pcn));
       psbuf_put_4(pb, SSH_FXF_WRITE | SSH_FXF_CREAT | SSH_FXF_TRUNC);
       psbuf_put_vattr(pb, va, pctx);
       GETRESPONSE(pb, pctx->sshfd);
       rv = psbuf_expect_handle(pb, &fhand, &fhandlen);
       if (rv)
               goto out;

       /*
        * Do *not* create the local node before getting a response
        * from the server.  Otherwise we might screw up consistency,
        * namely that the node can be looked up before create has
        * returned (mind you, the kernel will unlock the directory
        * before the create call from userspace returns).
        */
       pn_new = allocnode(pu, pn, pcn->pcn_name, va);
       if (!pn_new) {
               struct puffs_framebuf *pb2 = psbuf_makeout();
               reqid = NEXTREQ(pctx);
               psbuf_req_str(pb2, SSH_FXP_REMOVE, reqid, PCNPATH(pcn));
               JUSTSEND(pb2, pctx->sshfd);
               rv = ENOMEM;
       }

       if (pn_new)
               puffs_newinfo_setcookie(pni, pn_new);

       reqid = NEXTREQ(pctx);
       psbuf_recycleout(pb);
       psbuf_req_data(pb, SSH_FXP_CLOSE, reqid, fhand, fhandlen);
       JUSTSEND(pb, pctx->sshfd);
       free(fhand);
       return rv;

out:
       free(fhand);
       PSSHFSRETURN(rv);
}

/*
* Open a file handle.  This is used for read and write.  We do not
* wait here for the success or failure of this operation.  This is
* because otherwise opening and closing file handles would block
* reading potentially cached information.  Rather, we defer the wait
* to read/write and therefore allow cached access without a wait.
*
* If we have not yet successfully opened a type of handle, we do wait
* here.  Also, if a lazy open fails, we revert back to the same
* state of waiting.
*/
int
psshfs_node_open(struct puffs_usermount *pu, puffs_cookie_t opc, int mode,
       const struct puffs_cred *pcr)
{
       struct puffs_cc *pcc = puffs_cc_getcc(pu);
       struct psshfs_ctx *pctx = puffs_getspecific(pu);
       struct puffs_framebuf *pb, *pb2;
       struct vattr va;
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       uint32_t reqid;
       int didread, didwrite;
       int rv = 0;

       if (pn->pn_va.va_type == VDIR)
               return 0;

       puffs_setback(pcc, PUFFS_SETBACK_INACT_N1);
       puffs_vattr_null(&va);
       didread = didwrite = 0;
       if (mode & FREAD && psn->fhand_r == NULL && psn->lazyopen_r == NULL) {
               pb = psbuf_makeout();

               reqid = NEXTREQ(pctx);
               psbuf_req_str(pb, SSH_FXP_OPEN, reqid, PNPATH(pn));
               psbuf_put_4(pb, SSH_FXF_READ);
               psbuf_put_vattr(pb, &va, pctx);

               if (puffs_framev_enqueue_cb(pu, pctx->sshfd_data, pb,
                   lazyopen_rresp, psn, 0) == -1) {
                       rv = errno;
                       puffs_framebuf_destroy(pb);
                       goto out;
               }

               psn->lazyopen_r = pb;
               didread = 1;
       }
       if (mode & FWRITE && psn->fhand_w == NULL && psn->lazyopen_w == NULL) {
               pb2 = psbuf_makeout();

               reqid = NEXTREQ(pctx);
               psbuf_req_str(pb2, SSH_FXP_OPEN, reqid, PNPATH(pn));
               psbuf_put_4(pb2, SSH_FXF_WRITE);
               psbuf_put_vattr(pb2, &va, pctx);

               if (puffs_framev_enqueue_cb(pu, pctx->sshfd_data, pb2,
                   lazyopen_wresp, psn, 0) == -1) {
                       rv = errno;
                       puffs_framebuf_destroy(pb2);
                       goto out;
               }

               psn->lazyopen_w = pb2;
               didwrite = 1;
       }
       psn->stat &= ~PSN_HANDLECLOSE;

out:
       /* wait? */
       if (didread && (psn->stat & PSN_DOLAZY_R) == 0) {
               assert(psn->lazyopen_r);

               rv = puffs_framev_framebuf_ccpromote(psn->lazyopen_r, pcc);
               lazyopen_rresp(pu, psn->lazyopen_r, psn, rv);
               if (psn->fhand_r) {
                       psn->stat |= PSN_DOLAZY_R;
               } else {
                       if (psn->lazyopen_err_r)
                               return psn->lazyopen_err_r;
                       return EINVAL;
               }
       }

       /* wait? */
       if (didwrite && (psn->stat & PSN_DOLAZY_W) == 0) {
               assert(psn->lazyopen_w);

               rv = puffs_framev_framebuf_ccpromote(psn->lazyopen_w, pcc);
               lazyopen_wresp(pu, psn->lazyopen_w, psn, rv);
               if (psn->fhand_w) {
                       psn->stat |= PSN_DOLAZY_W;
               } else {
                       if (psn->lazyopen_err_w)
                               return psn->lazyopen_err_w;
                       return EINVAL;
               }
       }

       return rv;
}

int
psshfs_node_inactive(struct puffs_usermount *pu, puffs_cookie_t opc)
{
       struct puffs_node *pn = opc;

       closehandles(pu, pn->pn_data, HANDLE_READ | HANDLE_WRITE);
       return 0;
}

int
psshfs_node_readdir(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct dirent *dent, off_t *readoff, size_t *reslen,
       const struct puffs_cred *pcr, int *eofflag,
       off_t *cookies, size_t *ncookies)
{
       struct puffs_cc *pcc = puffs_cc_getcc(pu);
       struct psshfs_ctx *pctx = puffs_getspecific(pu);
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       struct psshfs_dir *pd;
       size_t i;
       int rv, set_readdir;

restart:
       if (psn->stat & PSN_READDIR) {
               struct psshfs_wait pw;

               set_readdir = 0;
               pw.pw_cc = pcc;
               pw.pw_type = PWTYPE_READDIR;
               TAILQ_INSERT_TAIL(&psn->pw, &pw, pw_entries);
               puffs_cc_yield(pcc);
               goto restart;
       } else {
               psn->stat |= PSN_READDIR;
               set_readdir = 1;
       }

       *ncookies = 0;
       rv = sftp_readdir(pu, pctx, pn);
       if (rv) {
               goto out;
       }

       /* find next dirent */
       for (i = *readoff;;i++) {
               if (i >= psn->dentnext)
                       goto out;
               pd = &psn->dir[i];
               if (pd->valid)
                       break;
       }

       for (;;) {
               *readoff = i;
               if (!puffs_nextdent(&dent, pd->entryname,
                   pd->va.va_fileid, puffs_vtype2dt(pd->va.va_type), reslen)) {
                       rv = 0;
                       goto out;
               }

               /* find next entry, store possible nfs key */
               do {
                       if (++i >= psn->dentnext)
                               goto out;
                       pd = &psn->dir[i];
               } while (pd->valid == 0);
               PUFFS_STORE_DCOOKIE(cookies, ncookies, (off_t)i);
       }

out:
       if (rv == 0) {
               if (i >= psn->dentnext)
                       *eofflag = 1;

               *readoff = i;
       }

       if (set_readdir) {
               struct psshfs_wait *pw;

               /* all will likely run to completion because of cache */
               TAILQ_FOREACH(pw, &psn->pw, pw_entries) {
                       assert(pw->pw_type == PWTYPE_READDIR);
                       puffs_cc_schedule(pw->pw_cc);
                       TAILQ_REMOVE(&psn->pw, pw, pw_entries);
               }

               psn->stat &= ~PSN_READDIR;
       }

       return rv;
}

int
psshfs_node_read(struct puffs_usermount *pu, puffs_cookie_t opc, uint8_t *buf,
       off_t offset, size_t *resid, const struct puffs_cred *pcr,
       int ioflag)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       struct psshfs_wait *pwp;
       uint32_t readlen;

       if (pn->pn_va.va_type == VDIR) {
               rv = EISDIR;
               goto farout;
       }

       /* check that a lazyopen didn't fail */
       if (!psn->fhand_r && !psn->lazyopen_r) {
               rv = psn->lazyopen_err_r;
               goto farout;
       }

       /* if someone is already waiting for the lazyopen, "just" wait */
       if (psn->stat & PSN_LAZYWAIT_R) {
               struct psshfs_wait pw;

               assert(psn->lazyopen_r);

               pw.pw_cc = pcc;
               pw.pw_type = PWTYPE_READ1;
               TAILQ_INSERT_TAIL(&psn->pw, &pw, pw_entries);
               puffs_cc_yield(pcc);
       }

       /* if lazyopening, wait for the result */
       if (psn->lazyopen_r) {
               psn->stat |= PSN_LAZYWAIT_R;
               rv = puffs_framev_framebuf_ccpromote(psn->lazyopen_r, pcc);
               lazyopen_rresp(pu, psn->lazyopen_r, psn, rv);

               /* schedule extra waiters */
               TAILQ_FOREACH(pwp, &psn->pw, pw_entries)
                       if (pwp->pw_type == PWTYPE_READ1) {
                               puffs_cc_schedule(pwp->pw_cc);
                               TAILQ_REMOVE(&psn->pw, pwp, pw_entries);
                       }
               psn->stat &= ~PSN_LAZYWAIT_R;

               if ((rv = psn->lazyopen_err_r) != 0)
                       goto farout;
       }

       /* if there is still no handle, just refuse to live with this */
       if (!psn->fhand_r) {
               rv = EINVAL;
               goto farout;
       }

again:
       readlen = *resid;
       psbuf_req_data(pb, SSH_FXP_READ, reqid, psn->fhand_r, psn->fhand_r_len);
       psbuf_put_8(pb, offset);
       psbuf_put_4(pb, readlen);

       /*
        * Do this *after* accessing the file, the handle might not
        * exist after blocking.
        */
       if (max_reads && ++psn->readcount > max_reads) {
               struct psshfs_wait pw;

               pw.pw_cc = pcc;
               pw.pw_type = PWTYPE_READ2;
               TAILQ_INSERT_TAIL(&psn->pw, &pw, pw_entries);
               puffs_cc_yield(pcc);
       }

       GETRESPONSE(pb, pctx->sshfd_data);

       rv = psbuf_do_data(pb, buf, &readlen);
       if (rv == 0) {
               *resid -= readlen;
               buf += readlen;
               offset += readlen;
       }

out:
       if (max_reads && --psn->readcount >= max_reads) {
               TAILQ_FOREACH(pwp, &psn->pw, pw_entries)
                       if (pwp->pw_type == PWTYPE_READ2)
                               break;
               assert(pwp != NULL);
               puffs_cc_schedule(pwp->pw_cc);
               TAILQ_REMOVE(&psn->pw, pwp, pw_entries);
       }

       if (rv == 0 && *resid > 0 && readlen > 0) {
               reqid = NEXTREQ(pctx);
               psbuf_recycleout(pb);
               goto again;
       }

farout:
       /* check if we need a lazyclose */
       if (psn->stat & PSN_HANDLECLOSE && psn->fhand_r) {
               TAILQ_FOREACH(pwp, &psn->pw, pw_entries)
                       if (pwp->pw_type == PWTYPE_READ1)
                               break;
               if (pwp == NULL)
                       closehandles(pu, psn, HANDLE_READ);
       }
       PSSHFSRETURN(rv);
}

/* XXX: we should getattr for size */
int
psshfs_node_write(struct puffs_usermount *pu, puffs_cookie_t opc, uint8_t *buf,
       off_t offset, size_t *resid, const struct puffs_cred *cred,
       int ioflag)
{
       PSSHFSAUTOVAR(pu);
       struct psshfs_wait *pwp;
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       uint32_t writelen;

       if (pn->pn_va.va_type == VDIR) {
               rv = EISDIR;
               goto out;
       }

       /* check that a lazyopen didn't fail */
       if (!psn->fhand_w && !psn->lazyopen_w) {
               rv = psn->lazyopen_err_w;
               goto out;
       }

       if (psn->stat & PSN_LAZYWAIT_W) {
               struct psshfs_wait pw;

               assert(psn->lazyopen_w);

               pw.pw_cc = pcc;
               pw.pw_type = PWTYPE_WRITE;
               TAILQ_INSERT_TAIL(&psn->pw, &pw, pw_entries);
               puffs_cc_yield(pcc);
       }

       /*
        * If lazyopening, wait for the result.
        * There can still be more than oen writer at a time in case
        * the kernel issues write FAFs.
        */
       if (psn->lazyopen_w) {
               psn->stat |= PSN_LAZYWAIT_W;
               rv = puffs_framev_framebuf_ccpromote(psn->lazyopen_w, pcc);
               lazyopen_wresp(pu, psn->lazyopen_w, psn, rv);

               /* schedule extra waiters */
               TAILQ_FOREACH(pwp, &psn->pw, pw_entries)
                       if (pwp->pw_type == PWTYPE_WRITE) {
                               puffs_cc_schedule(pwp->pw_cc);
                               TAILQ_REMOVE(&psn->pw, pwp, pw_entries);
                       }
               psn->stat &= ~PSN_LAZYWAIT_W;

               if ((rv = psn->lazyopen_err_w) != 0)
                       goto out;
       }

       if (!psn->fhand_w) {
               abort();
               rv = EINVAL;
               goto out;
       }

       writelen = *resid;
       psbuf_req_data(pb, SSH_FXP_WRITE, reqid, psn->fhand_w,psn->fhand_w_len);
       psbuf_put_8(pb, offset);
       psbuf_put_data(pb, buf, writelen);
       GETRESPONSE(pb, pctx->sshfd_data);

       rv = psbuf_expect_status(pb);
       if (rv == 0)
               *resid = 0;

       if (pn->pn_va.va_size < (uint64_t)offset + writelen)
               pn->pn_va.va_size = offset + writelen;

out:
       /* check if we need a lazyclose */
       if (psn->stat & PSN_HANDLECLOSE && psn->fhand_w) {
               TAILQ_FOREACH(pwp, &psn->pw, pw_entries)
                       if (pwp->pw_type == PWTYPE_WRITE)
                               break;
               if (pwp == NULL)
                       closehandles(pu, psn, HANDLE_WRITE);
       }
       PSSHFSRETURN(rv);
}

int
psshfs_node_readlink(struct puffs_usermount *pu, puffs_cookie_t opc,
       const struct puffs_cred *cred, char *linkvalue, size_t *linklen)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn = opc;
       struct psshfs_node *psn = pn->pn_data;
       uint32_t count;

       if (pctx->protover < 3) {
               rv = EOPNOTSUPP;
               goto out;
       }

       /*
        * check if we can use a cached version
        *
        * XXX: we might end up reading the same link multiple times
        * from the server if we get many requests at once, but that's
        * quite harmless as this routine is reentrant.
        */
       if (psn->symlink && !REFRESHTIMEOUT(pctx, time(NULL) - psn->slread))
               goto copy;

       if (psn->symlink) {
               free(psn->symlink);
               psn->symlink = NULL;
               psn->slread = 0;
       }

       psbuf_req_str(pb, SSH_FXP_READLINK, reqid, PNPATH(pn));
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_name(pb, &count);
       if (rv)
               goto out;
       if (count != 1) {
               rv = EPROTO;
               goto out;
       }

       rv = psbuf_get_str(pb, &psn->symlink, NULL);
       if (rv)
               goto out;
       psn->slread = time(NULL);

copy:
       *linklen = strlen(psn->symlink);
       (void) memcpy(linkvalue, psn->symlink, *linklen);

out:
       PSSHFSRETURN(rv);
}

static int
doremove(struct puffs_usermount *pu, struct puffs_node *pn_dir,
       struct puffs_node *pn, const char *name)
{
       PSSHFSAUTOVAR(pu);
       int op;

       if (pn->pn_va.va_type == VDIR)
               op = SSH_FXP_RMDIR;
       else
               op = SSH_FXP_REMOVE;

       psbuf_req_str(pb, op, reqid, PNPATH(pn));
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_status(pb);
       if (rv == 0)
               nukenode(pn, name, 0);

out:
       PSSHFSRETURN(rv);
}

int
psshfs_node_remove(struct puffs_usermount *pu, puffs_cookie_t opc,
       puffs_cookie_t targ, const struct puffs_cn *pcn)
{
       struct puffs_node *pn_targ = targ;
       int rv;

       assert(pn_targ->pn_va.va_type != VDIR);

       rv = doremove(pu, opc, targ, pcn->pcn_name);
       if (rv == 0)
               puffs_setback(puffs_cc_getcc(pu), PUFFS_SETBACK_NOREF_N2);

       return rv;
}

int
psshfs_node_rmdir(struct puffs_usermount *pu, puffs_cookie_t opc,
       puffs_cookie_t targ, const struct puffs_cn *pcn)
{
       struct puffs_node *pn_targ = targ;
       int rv;

       assert(pn_targ->pn_va.va_type == VDIR);

       rv = doremove(pu, opc, targ, pcn->pcn_name);
       if (rv == 0)
               puffs_setback(puffs_cc_getcc(pu), PUFFS_SETBACK_NOREF_N2);

       return rv;
}

int
psshfs_node_mkdir(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct puffs_newinfo *pni, const struct puffs_cn *pcn,
       const struct vattr *va)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn = opc;
       struct puffs_node *pn_new;

       psbuf_req_str(pb, SSH_FXP_MKDIR, reqid, PCNPATH(pcn));
       psbuf_put_vattr(pb, va, pctx);
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_status(pb);
       if (rv)
               goto out;

       pn_new = allocnode(pu, pn, pcn->pcn_name, va);
       if (pn_new) {
               puffs_newinfo_setcookie(pni, pn_new);
       } else {
               struct puffs_framebuf *pb2 = psbuf_makeout();
               reqid = NEXTREQ(pctx);
               psbuf_recycleout(pb2);
               psbuf_req_str(pb2, SSH_FXP_RMDIR, reqid, PCNPATH(pcn));
               JUSTSEND(pb2, pctx->sshfd);
               rv = ENOMEM;
       }

out:
       PSSHFSRETURN(rv);
}

int
psshfs_node_symlink(struct puffs_usermount *pu, puffs_cookie_t opc,
       struct puffs_newinfo *pni, const struct puffs_cn *pcn,
       const struct vattr *va, const char *link_target)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn = opc;
       struct puffs_node *pn_new;

       if (pctx->protover < 3) {
               rv = EOPNOTSUPP;
               goto out;
       }

       /*
        * XXX: ietf says: source, target.  openssh says: ietf who?
        * Let's go with openssh and build quirk tables later if we care
        */
       psbuf_req_str(pb, SSH_FXP_SYMLINK, reqid, link_target);
       psbuf_put_str(pb, PCNPATH(pcn));
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_status(pb);
       if (rv)
               goto out;

       pn_new = allocnode(pu, pn, pcn->pcn_name, va);
       if (pn_new) {
               puffs_newinfo_setcookie(pni, pn_new);
       } else {
               struct puffs_framebuf *pb2 = psbuf_makeout();
               reqid = NEXTREQ(pctx);
               psbuf_recycleout(pb2);
               psbuf_req_str(pb2, SSH_FXP_REMOVE, reqid, PCNPATH(pcn));
               JUSTSEND(pb2, pctx->sshfd);
               rv = ENOMEM;
       }

out:
       PSSHFSRETURN(rv);
}

int
psshfs_node_rename(struct puffs_usermount *pu, puffs_cookie_t opc,
       puffs_cookie_t src, const struct puffs_cn *pcn_src,
       puffs_cookie_t targ_dir, puffs_cookie_t targ,
       const struct puffs_cn *pcn_targ)
{
       PSSHFSAUTOVAR(pu);
       struct puffs_node *pn_sf = src;
       struct puffs_node *pn_td = targ_dir, *pn_tf = targ;
       struct psshfs_node *psn_src = pn_sf->pn_data;
       struct psshfs_node *psn_targdir = pn_td->pn_data;

       if (pctx->protover < 2) {
               rv = EOPNOTSUPP;
               goto out;
       }

       if (pn_tf) {
               rv = doremove(pu, targ_dir, pn_tf, pcn_targ->pcn_name);
               if (rv)
                       goto out;
       }

       psbuf_req_str(pb, SSH_FXP_RENAME, reqid, PCNPATH(pcn_src));
       psbuf_put_str(pb, PCNPATH(pcn_targ));
       GETRESPONSE(pb, pctx->sshfd);

       rv = psbuf_expect_status(pb);
       if (rv == 0) {
               struct psshfs_dir *pd;

               /*
                * XXX: interfaces didn't quite work with rename..
                * the song remains the same.  go figure .. ;)
                */
               nukenode(pn_sf, pcn_src->pcn_name, 0);
               pd = direnter(pn_td, pcn_targ->pcn_name);
               pd->entry = pn_sf;
               puffs_setvattr(&pd->va, &pn_sf->pn_va);

               if (opc != targ_dir) {
                       psn_targdir->childcount++;
                       psn_src->parent = pn_td;
                       if (pn_sf->pn_va.va_type == VDIR)
                               pn_td->pn_va.va_nlink++;
               }
       }

out:
       PSSHFSRETURN(rv);
}

/*
* So this file system happened to be written in such a way that
* lookup for ".." is hard if we lose the in-memory node.  We'd
* need to recreate the entire directory structure from the root
* node up to the ".." node we're looking up.
*
* And since our entire fs structure is purely fictional (i.e. it's
* only in-memory, not fetchable from the server), the easiest way
* to deal with it is to not allow nodes with children to be
* reclaimed.
*
* If a node with children is being attempted to be reclaimed, we
* just mark it "reclaimed" but leave it as is until all its children
* have been reclaimed.  If a lookup for that node is done meanwhile,
* it will be found by lookup() and we just remove the "reclaimed"
* bit.
*/
int
psshfs_node_reclaim(struct puffs_usermount *pu, puffs_cookie_t opc)
{
       struct puffs_node *pn = opc, *pn_next, *pn_root;
       struct psshfs_node *psn = pn->pn_data;

       /*
        * don't reclaim if we have file handle issued, otherwise
        * we can't do fhtonode
        */
       if (psn->stat & PSN_HASFH)
               return 0;

       psn->stat |= PSN_RECLAIMED;
       pn_root = puffs_getroot(pu);
       for (; pn != pn_root; pn = pn_next) {
               psn = pn->pn_data;
               if ((psn->stat & PSN_RECLAIMED) == 0 || psn->childcount != 0)
                       break;

               pn_next = psn->parent;
               doreclaim(pn);
       }

       return 0;
}