sys/miscfs/umapfs/umap_vfsops.c

   1 /*      $NetBSD: umap_vfsops.c,v 1.81 2008/12/05 13:05:38 ad Exp $      */
   2
   3 /*
   4  * Copyright (c) 1992, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software donated to Berkeley by
   8  * the UCLA Ficus project.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      from: @(#)null_vfsops.c       1.5 (Berkeley) 7/10/92
  35  *      @(#)umap_vfsops.c       8.8 (Berkeley) 5/14/95
  36  */
  37
  38 /*
  39  * Umap Layer
  40  * (See mount_umap(8) for a description of this layer.)
  41  */
  42
  43 #include <sys/cdefs.h>
  44 __KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.81 2008/12/05 13:05:38 ad Exp $");
  45
  46 #include <sys/param.h>
  47 #include <sys/systm.h>
  48 #include <sys/sysctl.h>
  49 #include <sys/proc.h>
  50 #include <sys/time.h>
  51 #include <sys/vnode.h>
  52 #include <sys/mount.h>
  53 #include <sys/namei.h>
  54 #include <sys/malloc.h>
  55 #include <sys/kauth.h>
  56 #include <sys/module.h>
  57
  58 #include <miscfs/umapfs/umap.h>
  59 #include <miscfs/genfs/layer_extern.h>
  60
  61 MODULE(MODULE_CLASS_VFS, umapfs, "layerfs");
  62
  63 VFS_PROTOS(umapfs);
  64
  65 static struct sysctllog *umapfs_sysctl_log;
  66
  67 /*
  68  * Mount umap layer
  69  */
  70 int
  71 umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
  72 {
  73         struct lwp *l = curlwp;
  74         struct nameidata nd;
  75         struct umap_args *args = data;
  76         struct vnode *lowerrootvp, *vp;
  77         struct umap_mount *amp;
  78         int error;
  79 #ifdef UMAPFS_DIAGNOSTIC
  80         int i;
  81 #endif
  82
  83         if (*data_len < sizeof *args)
  84                 return EINVAL;
  85
  86         if (mp->mnt_flag & MNT_GETARGS) {
  87                 amp = MOUNTTOUMAPMOUNT(mp);
  88                 if (amp == NULL)
  89                         return EIO;
  90                 args->la.target = NULL;
  91                 args->nentries = amp->info_nentries;
  92                 args->gnentries = amp->info_gnentries;
  93                 *data_len = sizeof *args;
  94                 return 0;
  95         }
  96
  97         /* only for root */
  98         if ((error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
  99             NULL)) != 0)
 100                 return error;
 101
 102 #ifdef UMAPFS_DIAGNOSTIC
 103         printf("umapfs_mount(mp = %p)\n", mp);
 104 #endif
 105
 106         /*
 107          * Update is not supported
 108          */
 109         if (mp->mnt_flag & MNT_UPDATE)
 110                 return EOPNOTSUPP;
 111
 112         /*
 113          * Find lower node
 114          */
 115         NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF,
 116                 UIO_USERSPACE, args->umap_target);
 117         if ((error = namei(&nd)) != 0)
 118                 return (error);
 119
 120         /*
 121          * Sanity check on lower vnode
 122          */
 123         lowerrootvp = nd.ni_vp;
 124 #ifdef UMAPFS_DIAGNOSTIC
 125         printf("vp = %p, check for VDIR...\n", lowerrootvp);
 126 #endif
 127
 128         if (lowerrootvp->v_type != VDIR) {
 129                 vput(lowerrootvp);
 130                 return (EINVAL);
 131         }
 132
 133 #ifdef UMAPFS_DIAGNOSTIC
 134         printf("mp = %p\n", mp);
 135 #endif
 136
 137         amp = (struct umap_mount *) malloc(sizeof(struct umap_mount),
 138                                 M_UFSMNT, M_WAITOK);    /* XXX */
 139         memset(amp, 0, sizeof(struct umap_mount));
 140
 141         mp->mnt_data = amp;
 142         amp->umapm_vfs = lowerrootvp->v_mount;
 143         if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
 144                 mp->mnt_flag |= MNT_LOCAL;
 145
 146         /*
 147          * Now copy in the number of entries and maps for umap mapping.
 148          */
 149         if (args->nentries > MAPFILEENTRIES || args->gnentries > GMAPFILEENTRIES) {
 150                 vput(lowerrootvp);
 151                 return (error);
 152         }
 153
 154         amp->info_nentries = args->nentries;
 155         amp->info_gnentries = args->gnentries;
 156         error = copyin(args->mapdata, amp->info_mapdata,
 157             2*sizeof(u_long)*args->nentries);
 158         if (error) {
 159                 vput(lowerrootvp);
 160                 return (error);
 161         }
 162
 163 #ifdef UMAPFS_DIAGNOSTIC
 164         printf("umap_mount:nentries %d\n",args->nentries);
 165         for (i = 0; i < args->nentries; i++)
 166                 printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
 167                     amp->info_mapdata[i][1]);
 168 #endif
 169
 170         error = copyin(args->gmapdata, amp->info_gmapdata,
 171             2*sizeof(u_long)*args->gnentries);
 172         if (error) {
 173                 vput(lowerrootvp);
 174                 return (error);
 175         }
 176
 177 #ifdef UMAPFS_DIAGNOSTIC
 178         printf("umap_mount:gnentries %d\n",args->gnentries);
 179         for (i = 0; i < args->gnentries; i++)
 180                 printf("\tgroup %ld maps to %ld\n",
 181                     amp->info_gmapdata[i][0],
 182                     amp->info_gmapdata[i][1]);
 183 #endif
 184
 185         /*
 186          * Make sure the mount point's sufficiently initialized
 187          * that the node create call will work.
 188          */
 189         vfs_getnewfsid(mp);
 190         amp->umapm_size = sizeof(struct umap_node);
 191         amp->umapm_tag = VT_UMAP;
 192         amp->umapm_bypass = umap_bypass;
 193         amp->umapm_alloc = layer_node_alloc;    /* the default alloc is fine */
 194         amp->umapm_vnodeop_p = umap_vnodeop_p;
 195         mutex_init(&amp->umapm_hashlock, MUTEX_DEFAULT, IPL_NONE);
 196         amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, true,
 197             &amp->umapm_node_hash);
 198
 199
 200         /*
 201          * fix up umap node for root vnode.
 202          */
 203         error = layer_node_create(mp, lowerrootvp, &vp);
 204         /*
 205          * Make sure the node alias worked
 206          */
 207         if (error) {
 208                 vput(lowerrootvp);
 209                 hashdone(amp->umapm_node_hashtbl, HASH_LIST,
 210                     amp->umapm_node_hash);
 211                 free(amp, M_UFSMNT);    /* XXX */
 212                 return (error);
 213         }
 214         /*
 215          * Unlock the node (either the lower or the alias)
 216          */
 217         vp->v_vflag |= VV_ROOT;
 218         VOP_UNLOCK(vp, 0);
 219
 220         /*
 221          * Keep a held reference to the root vnode.
 222          * It is vrele'd in umapfs_unmount.
 223          */
 224         amp->umapm_rootvp = vp;
 225
 226         error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
 227             UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
 228 #ifdef UMAPFS_DIAGNOSTIC
 229         printf("umapfs_mount: lower %s, alias at %s\n",
 230                 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
 231 #endif
 232         return error;
 233 }
 234
 235 /*
 236  * Free reference to umap layer
 237  */
 238 int
 239 umapfs_unmount(struct mount *mp, int mntflags)
 240 {
 241         struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
 242         struct vnode *rtvp = amp->umapm_rootvp;
 243         int error;
 244         int flags = 0;
 245
 246 #ifdef UMAPFS_DIAGNOSTIC
 247         printf("umapfs_unmount(mp = %p)\n", mp);
 248 #endif
 249
 250         if (mntflags & MNT_FORCE)
 251                 flags |= FORCECLOSE;
 252
 253         if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
 254                 return (EBUSY);
 255         if ((error = vflush(mp, rtvp, flags)) != 0)
 256                 return (error);
 257
 258 #ifdef UMAPFS_DIAGNOSTIC
 259         vprint("alias root of lower", rtvp);
 260 #endif
 261         /*
 262          * Blow it away for future re-use
 263          */
 264         vgone(rtvp);
 265         /*
 266          * Finally, throw away the umap_mount structure
 267          */
 268         mutex_destroy(&amp->umapm_hashlock);
 269         hashdone(amp->umapm_node_hashtbl, HASH_LIST, amp->umapm_node_hash);
 270         free(amp, M_UFSMNT);    /* XXX */
 271         mp->mnt_data = NULL;
 272         return (0);
 273 }
 274
 275 extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
 276
 277 const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
 278         &umapfs_vnodeop_opv_desc,
 279         NULL,
 280 };
 281
 282 struct vfsops umapfs_vfsops = {
 283         MOUNT_UMAP,
 284         sizeof (struct umap_args),
 285         umapfs_mount,
 286         layerfs_start,
 287         umapfs_unmount,
 288         layerfs_root,
 289         layerfs_quotactl,
 290         layerfs_statvfs,
 291         layerfs_sync,
 292         layerfs_vget,
 293         layerfs_fhtovp,
 294         layerfs_vptofh,
 295         layerfs_init,
 296         NULL,
 297         layerfs_done,
 298         NULL,                           /* vfs_mountroot */
 299         layerfs_snapshot,
 300         vfs_stdextattrctl,
 301         (void *)eopnotsupp,             /* vfs_suspendctl */
 302         layerfs_renamelock_enter,
 303         layerfs_renamelock_exit,
 304         (void *)eopnotsupp,
 305         umapfs_vnodeopv_descs,
 306         0,                              /* vfs_refcount */
 307         { NULL, NULL },
 308 };
 309
 310 static int
 311 umapfs_modcmd(modcmd_t cmd, void *arg)
 312 {
 313         int error;
 314
 315         switch (cmd) {
 316         case MODULE_CMD_INIT:
 317                 error = vfs_attach(&umapfs_vfsops);
 318                 if (error != 0)
 319                         break;
 320                 sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
 321                                CTLFLAG_PERMANENT,
 322                                CTLTYPE_NODE, "vfs", NULL,
 323                                NULL, 0, NULL, 0,
 324                                CTL_VFS, CTL_EOL);
 325                 sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
 326                                CTLFLAG_PERMANENT,
 327                                CTLTYPE_NODE, "umap",
 328                                SYSCTL_DESCR("UID/GID remapping file system"),
 329                                NULL, 0, NULL, 0,
 330                                CTL_VFS, 10, CTL_EOL);
 331                 /*
 332                  * XXX the "10" above could be dynamic, thereby eliminating
 333                  * one more instance of the "number to vfs" mapping problem,
 334                  * but "10" is the order as taken from sys/mount.h
 335                  */
 336                 break;
 337         case MODULE_CMD_FINI:
 338                 error = vfs_detach(&umapfs_vfsops);
 339                 if (error != 0)
 340                         break;
 341                 sysctl_teardown(&umapfs_sysctl_log);
 342                 break;
 343         default:
 344                 error = ENOTTY;
 345                 break;
 346         }
 347
 348         return (error);
 349 }