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umap_vfsops.c revision 1.79
      1 /*	$NetBSD: umap_vfsops.c,v 1.79 2008/05/13 08:31:13 simonb 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 1.79 2008/05/13 08:31:13 simonb 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, NULL);
     62 
     63 VFS_PROTOS(umapfs);
     64 
     65 /*
     66  * Mount umap layer
     67  */
     68 int
     69 umapfs_mount(mp, path, data, data_len)
     70 	struct mount *mp;
     71 	const char *path;
     72 	void *data;
     73 	size_t *data_len;
     74 {
     75 	struct lwp *l = curlwp;
     76 	struct nameidata nd;
     77 	struct umap_args *args = data;
     78 	struct vnode *lowerrootvp, *vp;
     79 	struct umap_mount *amp;
     80 	int error;
     81 #ifdef UMAPFS_DIAGNOSTIC
     82 	int i;
     83 #endif
     84 
     85 	if (*data_len < sizeof *args)
     86 		return EINVAL;
     87 
     88 	if (mp->mnt_flag & MNT_GETARGS) {
     89 		amp = MOUNTTOUMAPMOUNT(mp);
     90 		if (amp == NULL)
     91 			return EIO;
     92 		args->la.target = NULL;
     93 		args->nentries = amp->info_nentries;
     94 		args->gnentries = amp->info_gnentries;
     95 		*data_len = sizeof *args;
     96 		return 0;
     97 	}
     98 
     99 	/* only for root */
    100 	if ((error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
    101 	    NULL)) != 0)
    102 		return error;
    103 
    104 #ifdef UMAPFS_DIAGNOSTIC
    105 	printf("umapfs_mount(mp = %p)\n", mp);
    106 #endif
    107 
    108 	/*
    109 	 * Update is not supported
    110 	 */
    111 	if (mp->mnt_flag & MNT_UPDATE)
    112 		return EOPNOTSUPP;
    113 
    114 	/*
    115 	 * Find lower node
    116 	 */
    117 	NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF,
    118 		UIO_USERSPACE, args->umap_target);
    119 	if ((error = namei(&nd)) != 0)
    120 		return (error);
    121 
    122 	/*
    123 	 * Sanity check on lower vnode
    124 	 */
    125 	lowerrootvp = nd.ni_vp;
    126 #ifdef UMAPFS_DIAGNOSTIC
    127 	printf("vp = %p, check for VDIR...\n", lowerrootvp);
    128 #endif
    129 
    130 	if (lowerrootvp->v_type != VDIR) {
    131 		vput(lowerrootvp);
    132 		return (EINVAL);
    133 	}
    134 
    135 #ifdef UMAPFS_DIAGNOSTIC
    136 	printf("mp = %p\n", mp);
    137 #endif
    138 
    139 	amp = (struct umap_mount *) malloc(sizeof(struct umap_mount),
    140 				M_UFSMNT, M_WAITOK);	/* XXX */
    141 	memset(amp, 0, sizeof(struct umap_mount));
    142 
    143 	mp->mnt_data = amp;
    144 	amp->umapm_vfs = lowerrootvp->v_mount;
    145 	if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
    146 		mp->mnt_flag |= MNT_LOCAL;
    147 
    148 	/*
    149 	 * Now copy in the number of entries and maps for umap mapping.
    150 	 */
    151 	if (args->nentries > MAPFILEENTRIES || args->gnentries > GMAPFILEENTRIES) {
    152 		vput(lowerrootvp);
    153 		return (error);
    154 	}
    155 
    156 	amp->info_nentries = args->nentries;
    157 	amp->info_gnentries = args->gnentries;
    158 	error = copyin(args->mapdata, amp->info_mapdata,
    159 	    2*sizeof(u_long)*args->nentries);
    160 	if (error) {
    161 		vput(lowerrootvp);
    162 		return (error);
    163 	}
    164 
    165 #ifdef UMAPFS_DIAGNOSTIC
    166 	printf("umap_mount:nentries %d\n",args->nentries);
    167 	for (i = 0; i < args->nentries; i++)
    168 		printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
    169 	 	    amp->info_mapdata[i][1]);
    170 #endif
    171 
    172 	error = copyin(args->gmapdata, amp->info_gmapdata,
    173 	    2*sizeof(u_long)*args->gnentries);
    174 	if (error) {
    175 		vput(lowerrootvp);
    176 		return (error);
    177 	}
    178 
    179 #ifdef UMAPFS_DIAGNOSTIC
    180 	printf("umap_mount:gnentries %d\n",args->gnentries);
    181 	for (i = 0; i < args->gnentries; i++)
    182 		printf("\tgroup %ld maps to %ld\n",
    183 		    amp->info_gmapdata[i][0],
    184 	 	    amp->info_gmapdata[i][1]);
    185 #endif
    186 
    187 	/*
    188 	 * Make sure the mount point's sufficiently initialized
    189 	 * that the node create call will work.
    190 	 */
    191 	vfs_getnewfsid(mp);
    192 	amp->umapm_size = sizeof(struct umap_node);
    193 	amp->umapm_tag = VT_UMAP;
    194 	amp->umapm_bypass = umap_bypass;
    195 	amp->umapm_alloc = layer_node_alloc;	/* the default alloc is fine */
    196 	amp->umapm_vnodeop_p = umap_vnodeop_p;
    197 	mutex_init(&amp->umapm_hashlock, MUTEX_DEFAULT, IPL_NONE);
    198 	amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, true,
    199 	    &amp->umapm_node_hash);
    200 
    201 
    202 	/*
    203 	 * fix up umap node for root vnode.
    204 	 */
    205 	error = layer_node_create(mp, lowerrootvp, &vp);
    206 	/*
    207 	 * Make sure the node alias worked
    208 	 */
    209 	if (error) {
    210 		vput(lowerrootvp);
    211 		hashdone(amp->umapm_node_hashtbl, HASH_LIST,
    212 		    amp->umapm_node_hash);
    213 		free(amp, M_UFSMNT);	/* XXX */
    214 		return (error);
    215 	}
    216 	/*
    217 	 * Unlock the node (either the lower or the alias)
    218 	 */
    219 	vp->v_vflag |= VV_ROOT;
    220 	VOP_UNLOCK(vp, 0);
    221 
    222 	/*
    223 	 * Keep a held reference to the root vnode.
    224 	 * It is vrele'd in umapfs_unmount.
    225 	 */
    226 	amp->umapm_rootvp = vp;
    227 
    228 	error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
    229 	    UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
    230 #ifdef UMAPFS_DIAGNOSTIC
    231 	printf("umapfs_mount: lower %s, alias at %s\n",
    232 		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
    233 #endif
    234 	return error;
    235 }
    236 
    237 /*
    238  * Free reference to umap layer
    239  */
    240 int
    241 umapfs_unmount(struct mount *mp, int mntflags)
    242 {
    243 	struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
    244 	struct vnode *rtvp = amp->umapm_rootvp;
    245 	int error;
    246 	int flags = 0;
    247 
    248 #ifdef UMAPFS_DIAGNOSTIC
    249 	printf("umapfs_unmount(mp = %p)\n", mp);
    250 #endif
    251 
    252 	if (mntflags & MNT_FORCE)
    253 		flags |= FORCECLOSE;
    254 
    255 	if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
    256 		return (EBUSY);
    257 	if ((error = vflush(mp, rtvp, flags)) != 0)
    258 		return (error);
    259 
    260 #ifdef UMAPFS_DIAGNOSTIC
    261 	vprint("alias root of lower", rtvp);
    262 #endif
    263 	/*
    264 	 * Blow it away for future re-use
    265 	 */
    266 	vgone(rtvp);
    267 	/*
    268 	 * Finally, throw away the umap_mount structure
    269 	 */
    270 	mutex_destroy(&amp->umapm_hashlock);
    271 	hashdone(amp->umapm_node_hashtbl, HASH_LIST, amp->umapm_node_hash);
    272 	free(amp, M_UFSMNT);	/* XXX */
    273 	mp->mnt_data = NULL;
    274 	return (0);
    275 }
    276 
    277 SYSCTL_SETUP(sysctl_vfs_umap_setup, "sysctl vfs.umap subtree setup")
    278 {
    279 
    280 	sysctl_createv(clog, 0, NULL, NULL,
    281 		       CTLFLAG_PERMANENT,
    282 		       CTLTYPE_NODE, "vfs", NULL,
    283 		       NULL, 0, NULL, 0,
    284 		       CTL_VFS, CTL_EOL);
    285 	sysctl_createv(clog, 0, NULL, NULL,
    286 		       CTLFLAG_PERMANENT,
    287 		       CTLTYPE_NODE, "umap",
    288 		       SYSCTL_DESCR("UID/GID remapping file system"),
    289 		       NULL, 0, NULL, 0,
    290 		       CTL_VFS, 10, CTL_EOL);
    291 	/*
    292 	 * XXX the "10" above could be dynamic, thereby eliminating
    293 	 * one more instance of the "number to vfs" mapping problem,
    294 	 * but "10" is the order as taken from sys/mount.h
    295 	 */
    296 }
    297 
    298 extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
    299 
    300 const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
    301 	&umapfs_vnodeop_opv_desc,
    302 	NULL,
    303 };
    304 
    305 struct vfsops umapfs_vfsops = {
    306 	MOUNT_UMAP,
    307 	sizeof (struct umap_args),
    308 	umapfs_mount,
    309 	layerfs_start,
    310 	umapfs_unmount,
    311 	layerfs_root,
    312 	layerfs_quotactl,
    313 	layerfs_statvfs,
    314 	layerfs_sync,
    315 	layerfs_vget,
    316 	layerfs_fhtovp,
    317 	layerfs_vptofh,
    318 	layerfs_init,
    319 	NULL,
    320 	layerfs_done,
    321 	NULL,				/* vfs_mountroot */
    322 	layerfs_snapshot,
    323 	vfs_stdextattrctl,
    324 	(void *)eopnotsupp,		/* vfs_suspendctl */
    325 	layerfs_renamelock_enter,
    326 	layerfs_renamelock_exit,
    327 	(void *)eopnotsupp,
    328 	umapfs_vnodeopv_descs,
    329 	0,				/* vfs_refcount */
    330 	{ NULL, NULL },
    331 };
    332 
    333 static int
    334 umapfs_modcmd(modcmd_t cmd, void *arg)
    335 {
    336 
    337 	switch (cmd) {
    338 	case MODULE_CMD_INIT:
    339 		return vfs_attach(&umapfs_vfsops);
    340 	case MODULE_CMD_FINI:
    341 		return vfs_detach(&umapfs_vfsops);
    342 	default:
    343 		return ENOTTY;
    344 	}
    345 }
    346