/*      $NetBSD: mntfs.c,v 1.1.1.3 2015/01/17 16:34:15 christos Exp $   */

/*
* Copyright (c) 1997-2014 Erez Zadok
* Copyright (c) 1990 Jan-Simon Pendry
* Copyright (c) 1990 Imperial College of Science, Technology & Medicine
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry at Imperial College, London.
*
* 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. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
*
* File: am-utils/amd/mntfs.c
*
*/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <amd.h>

qelem mfhead = {&mfhead, &mfhead};

int mntfs_allocated;


am_loc *
dup_loc(am_loc *loc)
{
 loc->al_refc++;
 if (loc->al_mnt) {
   dup_mntfs(loc->al_mnt);
 }
 return loc;
}

mntfs *
dup_mntfs(mntfs *mf)
{
 if (mf->mf_refc == 0) {
   if (mf->mf_cid)
     untimeout(mf->mf_cid);
   mf->mf_cid = 0;
 }
 mf->mf_refc++;

 return mf;
}


static void
init_mntfs(mntfs *mf, am_ops *ops, am_opts *mo, char *mp, char *info, char *auto_opts, char *mopts, char *remopts)
{
 mf->mf_ops = ops;
 mf->mf_fsflags = ops->nfs_fs_flags;
 mf->mf_fo = 0;
 if (mo)
   mf->mf_fo = copy_opts(mo);

 mf->mf_mount = xstrdup(mp);
 mf->mf_info = xstrdup(info);
 mf->mf_auto = xstrdup(auto_opts);
 mf->mf_mopts = xstrdup(mopts);
 mf->mf_remopts = xstrdup(remopts);
 mf->mf_loopdev = NULL;
 mf->mf_refc = 1;
 mf->mf_flags = 0;
 mf->mf_error = -1;
 mf->mf_cid = 0;
 mf->mf_private = NULL;
 mf->mf_prfree = NULL;

 if (ops->ffserver)
   mf->mf_server = (*ops->ffserver) (mf);
 else
   mf->mf_server = NULL;
}


static mntfs *
alloc_mntfs(am_ops *ops, am_opts *mo, char *mp, char *info, char *auto_opts, char *mopts, char *remopts)
{
 mntfs *mf = ALLOC(struct mntfs);

 init_mntfs(mf, ops, mo, mp, info, auto_opts, mopts, remopts);
 ins_que(&mf->mf_q, &mfhead);
 mntfs_allocated++;

 return mf;
}


/* find a matching mntfs in our list */
mntfs *
locate_mntfs(am_ops *ops, am_opts *mo, char *mp, char *info, char *auto_opts, char *mopts, char *remopts)
{
 mntfs *mf;

 dlog("Locating mntfs reference to (%s,%s)", mp, info);

 ITER(mf, mntfs, &mfhead) {
   /*
    * For backwards compatibility purposes, we treat already-mounted
    * filesystems differently and only require a match of their mount point,
    * not of their server info. After all, there is little we can do if
    * the user asks us to mount two different things onto the same mount: one
    * will always cover the other one.
    */
   if (STREQ(mf->mf_mount, mp) &&
       ((mf->mf_flags & MFF_MOUNTED && !(mf->mf_fsflags & FS_DIRECT))
        || (STREQ(mf->mf_info, info) && mf->mf_ops == ops))) {
     /*
      * Handle cases where error ops are involved
      */
     if (ops == &amfs_error_ops) {
       /*
        * If the existing ops are not amfs_error_ops
        * then continue...
        */
       if (mf->mf_ops != &amfs_error_ops)
         continue;
       return dup_mntfs(mf);
     }

     dlog("mf->mf_flags = %#x", mf->mf_flags);

     if ((mf->mf_flags & MFF_RESTART) && amd_state < Finishing) {
       /*
        * Restart a previously mounted filesystem.
        */
       dlog("Restarting filesystem %s", mf->mf_mount);

       /*
        * If we are restarting an amd internal filesystem,
        * we need to initialize it a bit.
        *
        * We know it's internal because it is marked as toplvl.
        */
       if (mf->mf_ops == &amfs_toplvl_ops) {
         mf->mf_ops = ops;
         mf->mf_info = strealloc(mf->mf_info, info);
         ops->mounted(mf);     /* XXX: not right, but will do for now */
       }

       return mf;
     }

     if (!(mf->mf_flags & (MFF_MOUNTED | MFF_MOUNTING | MFF_UNMOUNTING))) {
       fserver *fs;
       mf->mf_flags &= ~MFF_ERROR;
       mf->mf_error = -1;
       mf->mf_auto = strealloc(mf->mf_auto, auto_opts);
       mf->mf_mopts = strealloc(mf->mf_mopts, mopts);
       mf->mf_remopts = strealloc(mf->mf_remopts, remopts);
       mf->mf_info = strealloc(mf->mf_info, info);

       if (mf->mf_private && mf->mf_prfree) {
         mf->mf_prfree(mf->mf_private);
         mf->mf_private = NULL;
       }

       fs = ops->ffserver ? (*ops->ffserver) (mf) : (fserver *) NULL;
       if (mf->mf_server)
         free_srvr(mf->mf_server);
       mf->mf_server = fs;
     }
     return dup_mntfs(mf);
   } /* end of "if (STREQ(mf-> ..." */
 } /* end of ITER */

 return 0;
}


/* find a matching mntfs in our list, create a new one if none is found */
mntfs *
find_mntfs(am_ops *ops, am_opts *mo, char *mp, char *info, char *auto_opts, char *mopts, char *remopts)
{
 mntfs *mf = locate_mntfs(ops, mo, mp, info, auto_opts, mopts, remopts);
 if (mf)
   return mf;

 return alloc_mntfs(ops, mo, mp, info, auto_opts, mopts, remopts);
}


mntfs *
new_mntfs(void)
{
 return alloc_mntfs(&amfs_error_ops, (am_opts *) NULL, "//nil//", ".", "", "", "");
}

am_loc *
new_loc(void)
{
 am_loc *loc = CALLOC(struct am_loc);
 loc->al_fo = 0;
 loc->al_mnt = new_mntfs();
 loc->al_refc = 1;
 return loc;
}


static void
uninit_mntfs(mntfs *mf)
{
 if (mf->mf_fo) {
   free_opts(mf->mf_fo);
   XFREE(mf->mf_fo);
 }
 XFREE(mf->mf_auto);
 XFREE(mf->mf_mopts);
 XFREE(mf->mf_remopts);
 XFREE(mf->mf_info);
 if (mf->mf_private && mf->mf_prfree)
   (*mf->mf_prfree) (mf->mf_private);

 XFREE(mf->mf_mount);

 /*
  * Clean up the file server
  */
 if (mf->mf_server)
   free_srvr(mf->mf_server);

 /*
  * Don't do a callback on this mount
  */
 if (mf->mf_cid) {
   untimeout(mf->mf_cid);
   mf->mf_cid = 0;
 }
}


static void
discard_mntfs(voidp v)
{
 mntfs *mf = v;

 rem_que(&mf->mf_q);

 /*
  * Free memory
  */
 uninit_mntfs(mf);
 XFREE(mf);

 --mntfs_allocated;
}

static void
discard_loc(voidp v)
{
 am_loc *loc = v;
 if (loc->al_fo) {
   free_opts(loc->al_fo);
   XFREE(loc->al_fo);
 }
 XFREE(loc);
}

void
flush_mntfs(void)
{
 mntfs *mf;

 mf = AM_FIRST(mntfs, &mfhead);
 while (mf != HEAD(mntfs, &mfhead)) {
   mntfs *mf2 = mf;
   mf = NEXT(mntfs, mf);
   if (mf2->mf_refc == 0 && mf2->mf_cid)
     discard_mntfs(mf2);
 }
}

void
free_loc(opaque_t arg)
{
 am_loc *loc = (am_loc *) arg;
 dlog("free_loc %p", loc);

 if (loc->al_refc <= 0) {
   plog(XLOG_ERROR, "IGNORING free_loc for 0x%p", loc);
   return;
 }

 if (loc->al_mnt)
   free_mntfs(loc->al_mnt);
 if (--loc->al_refc == 0) {
   discard_loc(loc);
 }
}

void
free_mntfs(opaque_t arg)
{
 mntfs *mf = (mntfs *) arg;

 dlog("free_mntfs <%s> type %s mf_refc %d flags %x",
      mf->mf_mount, mf->mf_ops->fs_type, mf->mf_refc, mf->mf_flags);

 /*
  * We shouldn't ever be called to free something that has
  * a non-positive refcount.  Something is badly wrong if
  * we have been!  Ignore the request for now...
  */
 if (mf->mf_refc <= 0) {
   plog(XLOG_ERROR, "IGNORING free_mntfs for <%s>: refc %d, flags %x (bug?)",
        mf->mf_mount, mf->mf_refc, mf->mf_flags);
   return;
 }

 /* don't discard last reference of a restarted/kept mntfs */
 if (mf->mf_refc == 1 && mf->mf_flags & MFF_RSTKEEP) {
   plog(XLOG_ERROR, "IGNORING free_mntfs for <%s>: refc %d, flags %x (restarted)",
        mf->mf_mount, mf->mf_refc, mf->mf_flags);
   return;
 }

 if (--mf->mf_refc == 0) {
   if (mf->mf_flags & MFF_MOUNTED) {
     int quoted;
     mf->mf_flags &= ~MFF_MOUNTED;

     /*
      * Record for posterity
      */
     quoted = strchr(mf->mf_info, ' ') != 0;   /* cheap */
     plog(XLOG_INFO, "%s%s%s %sed fstype %s from %s",
          quoted ? "\"" : "",
          mf->mf_info,
          quoted ? "\"" : "",
          mf->mf_error ? "discard" : "unmount",
          mf->mf_ops->fs_type, mf->mf_mount);
   }

   if (mf->mf_fsflags & FS_DISCARD) {
     dlog("Immediately discarding mntfs for %s", mf->mf_mount);
     discard_mntfs(mf);

   } else {

     if (mf->mf_flags & MFF_RESTART) {
       dlog("Discarding remount hook for %s", mf->mf_mount);
     } else {
       dlog("Discarding last mntfs reference to %s fstype %s",
            mf->mf_mount, mf->mf_ops->fs_type);
     }
     if (mf->mf_flags & (MFF_MOUNTED | MFF_MOUNTING | MFF_UNMOUNTING))
       dlog("mntfs reference for %s still active", mf->mf_mount);
     mf->mf_cid = timeout(ALLOWED_MOUNT_TIME, discard_mntfs, (voidp) mf);
   }
 }
}


mntfs *
realloc_mntfs(mntfs *mf, am_ops *ops, am_opts *mo, char *mp, char *info, char *auto_opts, char *mopts, char *remopts)
{
 mntfs *mf2;

 if (mf->mf_refc == 1 &&
     mf->mf_flags & MFF_RESTART &&
     STREQ(mf->mf_mount, mp)) {
   /*
    * If we are inheriting then just return
    * the same node...
    */
   return mf;
 }

 /*
  * Re-use the existing mntfs if it is mounted.
  * This traps a race in nfsx.
  */
 if (mf->mf_ops != &amfs_error_ops &&
     (mf->mf_flags & MFF_MOUNTED) &&
     !FSRV_ISDOWN(mf->mf_server)) {
   return mf;
 }

 mf2 = find_mntfs(ops, mo, mp, info, auto_opts, mopts, remopts);
 free_mntfs(mf);
 return mf2;
}

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