/*      $NetBSD: ops_cachefs.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/ops_cachefs.c
*
*/

/*
* Caching filesystem (Solaris 2.x)
*/

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

/* forward declarations */
static char *cachefs_match(am_opts *fo);
static int cachefs_init(mntfs *mf);
static int cachefs_mount(am_node *am, mntfs *mf);
static int cachefs_umount(am_node *am, mntfs *mf);


/*
* Ops structure
*/
am_ops cachefs_ops =
{
 "cachefs",
 cachefs_match,
 cachefs_init,
 cachefs_mount,
 cachefs_umount,
 amfs_error_lookup_child,
 amfs_error_mount_child,
 amfs_error_readdir,
 0,                            /* cachefs_readlink */
 0,                            /* cachefs_mounted */
 0,                            /* cachefs_umounted */
 amfs_generic_find_srvr,
 0,                            /* cachefs_get_wchan */
 FS_MKMNT | FS_NOTIMEOUT | FS_UBACKGROUND | FS_AMQINFO, /* nfs_fs_flags */
#ifdef HAVE_FS_AUTOFS
 AUTOFS_CACHEFS_FS_FLAGS,
#endif /* HAVE_FS_AUTOFS */
};


/*
* Check that f/s has all needed fields.
* Returns: matched string if found, NULL otherwise.
*/
static char *
cachefs_match(am_opts *fo)
{
 /* sanity check */
 if (!fo->opt_rfs || !fo->opt_fs || !fo->opt_cachedir) {
   plog(XLOG_USER, "cachefs: must specify cachedir, rfs, and fs");
   return NULL;
 }

 dlog("CACHEFS: using cache directory \"%s\"", fo->opt_cachedir);

 /* determine magic cookie to put in mtab */
 return xstrdup(fo->opt_cachedir);
}


/*
* Initialize.
* Returns: 0 if OK, non-zero (errno) if failed.
*/
static int
cachefs_init(mntfs *mf)
{
 /*
  * Save cache directory name
  */
 if (!mf->mf_private) {
   mf->mf_private = (voidp) xstrdup(mf->mf_fo->opt_cachedir);
   mf->mf_prfree = (void (*)(voidp)) free;
 }

 return 0;
}


/*
* mntpt is the mount point ($fs) [XXX: was 'dir']
* backdir is the mounted pathname ($rfs) [XXX: was 'fs_name']
* cachedir is the cache directory ($cachedir)
*/
static int
mount_cachefs(char *mntdir, char *backdir, char *cachedir,
             char *opts, int on_autofs)
{
 cachefs_args_t ca;
 mntent_t mnt;
 int flags;
 char *cp;
 MTYPE_TYPE type = MOUNT_TYPE_CACHEFS; /* F/S mount type */

 memset((voidp) &ca, 0, sizeof(ca)); /* Paranoid */

 /*
  * Fill in the mount structure
  */
 memset((voidp) &mnt, 0, sizeof(mnt));
 mnt.mnt_dir = mntdir;
 mnt.mnt_fsname = backdir;
 mnt.mnt_type = MNTTAB_TYPE_CACHEFS;
 mnt.mnt_opts = opts;

 flags = compute_mount_flags(&mnt);
#ifdef HAVE_FS_AUTOFS
 if (on_autofs)
   flags |= autofs_compute_mount_flags(&mnt);
#endif /* HAVE_FS_AUTOFS */

 /* Fill in cachefs mount arguments */

 /*
  * XXX: Caveats
  * (1) cache directory is NOT checked for sanity beforehand, nor is it
  * purged.  Maybe it should be purged first?
  * (2) cache directory is NOT locked.  Should we?
  */

 /* mount flags */
 ca.cfs_options.opt_flags = CFS_WRITE_AROUND | CFS_ACCESS_BACKFS;
 /* cache population size */
 ca.cfs_options.opt_popsize = DEF_POP_SIZE; /* default: 64K */
 /* filegrp size */
 ca.cfs_options.opt_fgsize = DEF_FILEGRP_SIZE; /* default: 256 */

 /* CFS ID for file system (must be unique) */
 ca.cfs_fsid = cachedir;

 /* CFS fscdir name */
 memset(ca.cfs_cacheid, 0, sizeof(ca.cfs_cacheid));
 /*
  * Append cacheid and mountpoint.
  * sizeof(cfs_cacheid) should be C_MAX_MOUNT_FSCDIRNAME as per
  * <sys/fs/cachefs_fs.h> (checked on Solaris 8).
  */
 xsnprintf(ca.cfs_cacheid, sizeof(ca.cfs_cacheid),
           "%s:%s", ca.cfs_fsid, mntdir);
 /* convert '/' to '_' (Solaris does that...) */
 cp = ca.cfs_cacheid;
 while ((cp = strpbrk(cp, "/")) != NULL)
   *cp = '_';

 /* path for this cache dir */
 ca.cfs_cachedir = cachedir;

 /* back filesystem dir */
 ca.cfs_backfs = backdir;

 /* same as nfs values (XXX: need to handle these options) */
 ca.cfs_acregmin = 0;
 ca.cfs_acregmax = 0;
 ca.cfs_acdirmin = 0;
 ca.cfs_acdirmax = 0;

 /*
  * Call generic mount routine
  */
 return mount_fs(&mnt, flags, (caddr_t) &ca, 0, type, 0, NULL, mnttab_file_name, on_autofs);
}


static int
cachefs_mount(am_node *am, mntfs *mf)
{
 int on_autofs = mf->mf_flags & MFF_ON_AUTOFS;
 int error;

 error = mount_cachefs(mf->mf_mount,
                       mf->mf_fo->opt_rfs,
                       mf->mf_fo->opt_cachedir,
                       mf->mf_mopts,
                       on_autofs);
 if (error) {
   errno = error;
   /* according to Solaris, if errno==ESRCH, "options to not match" */
   if (error == ESRCH)
     plog(XLOG_ERROR, "mount_cachefs: options to no match: %m");
   else
     plog(XLOG_ERROR, "mount_cachefs: %m");
   return error;
 }

 return 0;
}


static int
cachefs_umount(am_node *am, mntfs *mf)
{
 int unmount_flags = (mf->mf_flags & MFF_ON_AUTOFS) ? AMU_UMOUNT_AUTOFS : 0;
 int error;

 error = UMOUNT_FS(mf->mf_mount, mnttab_file_name, unmount_flags);

 /*
  * In the case of cachefs, we must fsck the cache directory.  Otherwise,
  * it will remain inconsistent, and the next cachefs mount will fail
  * with the error "no space left on device" (ENOSPC).
  *
  * XXX: this is hacky! use fork/exec/wait instead...
  */
 if (!error) {
   char *cachedir = NULL;
   char cmd[128];

   cachedir = (char *) mf->mf_private;
   plog(XLOG_INFO, "running fsck on cache directory \"%s\"", cachedir);
   xsnprintf(cmd, sizeof(cmd), "fsck -F cachefs %s", cachedir);
   system(cmd);
 }

 return error;
}

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