umap_vfsops.c revision 1.103
1/* $NetBSD: umap_vfsops.c,v 1.103 2020/04/13 19:23:19 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 1.103 2020/04/13 19:23:19 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/syslog.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 61MODULE(MODULE_CLASS_VFS, umap, "layerfs"); 62 63VFS_PROTOS(umapfs); 64 65/* 66 * Mount umap layer 67 */ 68int 69umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 70{ 71 struct lwp *l = curlwp; 72 struct pathbuf *pb; 73 struct nameidata nd; 74 struct umap_args *args = data; 75 struct vnode *lowerrootvp, *vp; 76 struct umap_mount *amp; 77 int error; 78#ifdef UMAPFS_DIAGNOSTIC 79 int i; 80#endif 81 fsid_t tfsid; 82 83 if (args == NULL) 84 return EINVAL; 85 if (*data_len < sizeof *args) { 86#ifdef UMAPFS_DIAGNOSTIC 87 printf("mount_umap: data len %d < args %d\n", 88 (int)*data_len, (int)(sizeof *args)); 89#endif 90 return EINVAL; 91 } 92 93 if (mp->mnt_flag & MNT_GETARGS) { 94 amp = MOUNTTOUMAPMOUNT(mp); 95 if (amp == NULL) 96 return EIO; 97 args->la.target = NULL; 98 args->nentries = amp->info_nentries; 99 args->gnentries = amp->info_gnentries; 100 *data_len = sizeof *args; 101 return 0; 102 } 103 104 /* only for root */ 105 error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT, 106 KAUTH_REQ_SYSTEM_MOUNT_UMAP, NULL, NULL, NULL); 107 if (error) 108 return error; 109 110#ifdef UMAPFS_DIAGNOSTIC 111 printf("umapfs_mount(mp = %p)\n", mp); 112#endif 113 114 /* 115 * Update is not supported 116 */ 117 if (mp->mnt_flag & MNT_UPDATE) 118 return EOPNOTSUPP; 119 120 /* 121 * Find lower node 122 */ 123 error = pathbuf_copyin(args->umap_target, &pb); 124 if (error) { 125 return error; 126 } 127 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb); 128 if ((error = namei(&nd)) != 0) { 129 pathbuf_destroy(pb); 130 return error; 131 } 132 133 /* 134 * Sanity check on lower vnode 135 */ 136 lowerrootvp = nd.ni_vp; 137 pathbuf_destroy(pb); 138#ifdef UMAPFS_DIAGNOSTIC 139 printf("vp = %p, check for VDIR...\n", lowerrootvp); 140#endif 141 142 if (lowerrootvp->v_type != VDIR) { 143 vput(lowerrootvp); 144 return (EINVAL); 145 } 146 147#ifdef UMAPFS_DIAGNOSTIC 148 printf("mp = %p\n", mp); 149#endif 150 151 amp = kmem_zalloc(sizeof(struct umap_mount), KM_SLEEP); 152 mp->mnt_data = amp; 153 154 /* 155 * Now copy in the number of entries and maps for umap mapping. 156 */ 157 if (args->nentries < 0 || args->nentries > MAPFILEENTRIES || 158 args->gnentries < 0 || args->gnentries > GMAPFILEENTRIES) { 159 vput(lowerrootvp); 160 return (EINVAL); 161 } 162 163 amp->info_nentries = args->nentries; 164 amp->info_gnentries = args->gnentries; 165 error = copyin(args->mapdata, amp->info_mapdata, 166 2*sizeof(u_long)*args->nentries); 167 if (error) { 168 vput(lowerrootvp); 169 return (error); 170 } 171 172#ifdef UMAPFS_DIAGNOSTIC 173 printf("umap_mount:nentries %d\n",args->nentries); 174 for (i = 0; i < args->nentries; i++) 175 printf(" %ld maps to %ld\n", amp->info_mapdata[i][0], 176 amp->info_mapdata[i][1]); 177#endif 178 179 error = copyin(args->gmapdata, amp->info_gmapdata, 180 2*sizeof(u_long)*args->gnentries); 181 if (error) { 182 vput(lowerrootvp); 183 return (error); 184 } 185 186#ifdef UMAPFS_DIAGNOSTIC 187 printf("umap_mount:gnentries %d\n",args->gnentries); 188 for (i = 0; i < args->gnentries; i++) 189 printf("\tgroup %ld maps to %ld\n", 190 amp->info_gmapdata[i][0], 191 amp->info_gmapdata[i][1]); 192#endif 193 194 /* 195 * Make sure the mount point's sufficiently initialized 196 * that the node create call will work. 197 */ 198 tfsid.__fsid_val[0] = (int32_t)args->fsid; 199 tfsid.__fsid_val[1] = makefstype(MOUNT_UMAP); 200 if (tfsid.__fsid_val[0] == 0) { 201 log(LOG_WARNING, "umapfs: fsid given as 0, ignoring\n"); 202 vfs_getnewfsid(mp); 203 } else if (vfs_getvfs(&tfsid)) { 204 log(LOG_WARNING, "umapfs: fsid %x already mounted\n", 205 tfsid.__fsid_val[0]); 206 vfs_getnewfsid(mp); 207 } else { 208 mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0]; 209 mp->mnt_stat.f_fsidx.__fsid_val[1] = tfsid.__fsid_val[1]; 210 mp->mnt_stat.f_fsid = tfsid.__fsid_val[0]; 211 } 212 log(LOG_DEBUG, "umapfs: using fsid %x/%x\n", 213 mp->mnt_stat.f_fsidx.__fsid_val[0], 214 mp->mnt_stat.f_fsidx.__fsid_val[1]); 215 mp->mnt_lower = lowerrootvp->v_mount; 216 217 amp->umapm_size = sizeof(struct umap_node); 218 amp->umapm_tag = VT_UMAP; 219 amp->umapm_bypass = umap_bypass; 220 amp->umapm_vnodeop_p = umap_vnodeop_p; 221 222 /* 223 * fix up umap node for root vnode. 224 */ 225 VOP_UNLOCK(lowerrootvp); 226 error = layer_node_create(mp, lowerrootvp, &vp); 227 /* 228 * Make sure the node alias worked 229 */ 230 if (error) { 231 vrele(lowerrootvp); 232 kmem_free(amp, sizeof(struct umap_mount)); 233 return error; 234 } 235 236 /* 237 * Keep a held reference to the root vnode. 238 * It is vrele'd in umapfs_unmount. 239 */ 240 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 241 vp->v_vflag |= VV_ROOT; 242 amp->umapm_rootvp = vp; 243 VOP_UNLOCK(vp); 244 245 error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target, 246 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 247 if (error) 248 return error; 249 250 if (mp->mnt_lower->mnt_flag & MNT_LOCAL) 251 mp->mnt_flag |= MNT_LOCAL; 252#ifdef UMAPFS_DIAGNOSTIC 253 printf("umapfs_mount: lower %s, alias at %s\n", 254 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 255#endif 256 return 0; 257} 258 259/* 260 * Free reference to umap layer 261 */ 262int 263umapfs_unmount(struct mount *mp, int mntflags) 264{ 265 struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp); 266 struct vnode *rtvp = amp->umapm_rootvp; 267 int error; 268 int flags = 0; 269 270#ifdef UMAPFS_DIAGNOSTIC 271 printf("umapfs_unmount(mp = %p)\n", mp); 272#endif 273 274 if (mntflags & MNT_FORCE) 275 flags |= FORCECLOSE; 276 277 if (vrefcnt(rtvp) > 1 && (mntflags & MNT_FORCE) == 0) 278 return (EBUSY); 279 if ((error = vflush(mp, rtvp, flags)) != 0) 280 return (error); 281 282#ifdef UMAPFS_DIAGNOSTIC 283 vprint("alias root of lower", rtvp); 284#endif 285 /* 286 * Blow it away for future re-use 287 */ 288 vgone(rtvp); 289 /* 290 * Finally, throw away the umap_mount structure 291 */ 292 kmem_free(amp, sizeof(struct umap_mount)); 293 mp->mnt_data = NULL; 294 return 0; 295} 296 297extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc; 298 299const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = { 300 &umapfs_vnodeop_opv_desc, 301 NULL, 302}; 303 304struct vfsops umapfs_vfsops = { 305 .vfs_name = MOUNT_UMAP, 306 .vfs_min_mount_data = sizeof (struct umap_args), 307 .vfs_mount = umapfs_mount, 308 .vfs_start = layerfs_start, 309 .vfs_unmount = umapfs_unmount, 310 .vfs_root = layerfs_root, 311 .vfs_quotactl = layerfs_quotactl, 312 .vfs_statvfs = layerfs_statvfs, 313 .vfs_sync = layerfs_sync, 314 .vfs_loadvnode = layerfs_loadvnode, 315 .vfs_vget = layerfs_vget, 316 .vfs_fhtovp = layerfs_fhtovp, 317 .vfs_vptofh = layerfs_vptofh, 318 .vfs_init = layerfs_init, 319 .vfs_done = layerfs_done, 320 .vfs_snapshot = layerfs_snapshot, 321 .vfs_extattrctl = vfs_stdextattrctl, 322 .vfs_suspendctl = layerfs_suspendctl, 323 .vfs_renamelock_enter = layerfs_renamelock_enter, 324 .vfs_renamelock_exit = layerfs_renamelock_exit, 325 .vfs_fsync = (void *)eopnotsupp, 326 .vfs_opv_descs = umapfs_vnodeopv_descs 327}; 328 329SYSCTL_SETUP(umapfs_sysctl_setup, "umapfs sysctl") 330{ 331 332 sysctl_createv(clog, 0, NULL, NULL, 333 CTLFLAG_PERMANENT, 334 CTLTYPE_NODE, "umap", 335 SYSCTL_DESCR("UID/GID remapping file system"), 336 NULL, 0, NULL, 0, 337 CTL_VFS, 10, CTL_EOL); 338 /* 339 * XXX the "10" above could be dynamic, thereby eliminating 340 * one more instance of the "number to vfs" mapping problem, 341 * but "10" is the order as taken from sys/mount.h 342 */ 343} 344 345static int 346umap_modcmd(modcmd_t cmd, void *arg) 347{ 348 int error; 349 350 switch (cmd) { 351 case MODULE_CMD_INIT: 352 error = vfs_attach(&umapfs_vfsops); 353 if (error != 0) 354 break; 355 break; 356 case MODULE_CMD_FINI: 357 error = vfs_detach(&umapfs_vfsops); 358 if (error != 0) 359 break; 360 break; 361 default: 362 error = ENOTTY; 363 break; 364 } 365 366 return (error); 367} 368