1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * This is the /dev (hence, the sdev_ prefix) filesystem.
28 */
29
30 #include <sys/types.h>
31 #include <sys/param.h>
32 #include <sys/sysmacros.h>
33 #include <sys/systm.h>
34 #include <sys/kmem.h>
35 #include <sys/time.h>
36 #include <sys/pathname.h>
37 #include <sys/vfs.h>
38 #include <sys/vfs_opreg.h>
39 #include <sys/vnode.h>
40 #include <sys/file.h>
41 #include <sys/stat.h>
42 #include <sys/uio.h>
43 #include <sys/stat.h>
44 #include <sys/errno.h>
45 #include <sys/cmn_err.h>
46 #include <sys/cred.h>
47 #include <sys/statvfs.h>
48 #include <sys/policy.h>
49 #include <sys/mount.h>
50 #include <sys/debug.h>
51 #include <sys/modctl.h>
52 #include <sys/mkdev.h>
53 #include <fs/fs_subr.h>
54 #include <sys/fs/sdev_impl.h>
55 #include <sys/fs/snode.h>
56 #include <sys/fs/dv_node.h>
57 #include <sys/sunndi.h>
58 #include <sys/mntent.h>
59
60 /*
61 * /dev vfs operations.
62 */
63
64 /*
65 * globals
66 */
67 struct sdev_data *sdev_origins; /* mount info for origins under /dev */
68 kmutex_t sdev_lock; /* used for mount/unmount/rename synchronization */
69
70 /*
71 * static
72 */
73 static major_t devmajor; /* the fictitious major we live on */
74 static major_t devminor; /* the fictitious minor of this instance */
75 static struct sdev_data *sdev_mntinfo = NULL; /* linked list of instances */
76
77 /* LINTED E_STATIC_UNUSED */ /* useful for debugging */
78 static struct vnode *sdev_stale_attrvp; /* stale root attrvp after remount */
79
80 static int sdev_mount(struct vfs *, struct vnode *, struct mounta *,
81 struct cred *);
82 static int sdev_unmount(struct vfs *, int, struct cred *);
83 static int sdev_root(struct vfs *, struct vnode **);
84 static int sdev_statvfs(struct vfs *, struct statvfs64 *);
85 static void sdev_insert_mntinfo(struct sdev_data *);
86 static int devinit(int, char *);
87
88 static vfsdef_t sdev_vfssw = {
89 VFSDEF_VERSION,
90 "dev", /* type name string */
91 devinit, /* init routine */
92 VSW_CANREMOUNT, /* flags */
93 NULL /* mount options table prototype */
94 };
95
96
97 /*
98 * Module linkage information
99 */
100 static struct modlfs modlfs = {
101 &mod_fsops, "/dev filesystem", &sdev_vfssw
102 };
103
104 static struct modlinkage modlinkage = {
105 MODREV_1, (void *)&modlfs, NULL
106 };
107
108 int
_init(void)109 _init(void)
110 {
111 int e;
112
113 mutex_init(&sdev_lock, NULL, MUTEX_DEFAULT, NULL);
114 sdev_node_cache_init();
115 sdev_devfsadm_lockinit();
116 if ((e = mod_install(&modlinkage)) != 0) {
117 sdev_devfsadm_lockdestroy();
118 sdev_node_cache_fini();
119 mutex_destroy(&sdev_lock);
120 return (e);
121 }
122 return (0);
123 }
124
125 /*
126 * dev module remained loaded for the global /dev instance
127 */
128 int
_fini(void)129 _fini(void)
130 {
131 return (EBUSY);
132 }
133
134 int
_info(struct modinfo * modinfop)135 _info(struct modinfo *modinfop)
136 {
137 return (mod_info(&modlinkage, modinfop));
138 }
139
140 /*ARGSUSED*/
141 static int
devinit(int fstype,char * name)142 devinit(int fstype, char *name)
143 {
144 static const fs_operation_def_t dev_vfsops_tbl[] = {
145 VFSNAME_MOUNT, { .vfs_mount = sdev_mount },
146 VFSNAME_UNMOUNT, { .vfs_unmount = sdev_unmount },
147 VFSNAME_ROOT, { .vfs_root = sdev_root },
148 VFSNAME_STATVFS, { .vfs_statvfs = sdev_statvfs },
149 NULL, NULL
150 };
151
152 int error;
153 extern major_t getudev(void);
154
155 devtype = fstype;
156
157 error = vfs_setfsops(fstype, dev_vfsops_tbl, NULL);
158 if (error != 0) {
159 cmn_err(CE_WARN, "devinit: bad vfs ops tbl");
160 return (error);
161 }
162
163 error = vn_make_ops("dev", sdev_vnodeops_tbl, &sdev_vnodeops);
164 if (error != 0) {
165 (void) vfs_freevfsops_by_type(fstype);
166 cmn_err(CE_WARN, "devinit: bad vnode ops tbl");
167 return (error);
168 }
169
170 if ((devmajor = getudev()) == (major_t)-1) {
171 cmn_err(CE_WARN, "%s: can't get unique dev", sdev_vfssw.name);
172 return (1);
173 }
174
175 /* initialize negative cache */
176 sdev_ncache_init();
177
178 return (0);
179 }
180
181 /*
182 * Both mount point and backing store directory name are
183 * passed in from userland
184 */
185 static int
sdev_mount(struct vfs * vfsp,struct vnode * mvp,struct mounta * uap,struct cred * cr)186 sdev_mount(struct vfs *vfsp, struct vnode *mvp, struct mounta *uap,
187 struct cred *cr)
188 {
189 struct sdev_data *sdev_data;
190 struct vnode *avp;
191 struct sdev_node *dv;
192 struct sdev_mountargs *args = NULL;
193 int error = 0;
194 dev_t devdev;
195
196 /*
197 * security check
198 */
199 if ((secpolicy_fs_mount(cr, mvp, vfsp) != 0) ||
200 (secpolicy_sys_devices(cr) != 0))
201 return (EPERM);
202
203 /*
204 * Sanity check the mount point
205 */
206 if (mvp->v_type != VDIR)
207 return (ENOTDIR);
208
209 /*
210 * Sanity Check for overlay mount.
211 */
212 mutex_enter(&mvp->v_lock);
213 if ((uap->flags & MS_OVERLAY) == 0 &&
214 (uap->flags & MS_REMOUNT) == 0 &&
215 (mvp->v_count > 1 || (mvp->v_flag & VROOT))) {
216 mutex_exit(&mvp->v_lock);
217 return (EBUSY);
218 }
219 mutex_exit(&mvp->v_lock);
220
221 args = kmem_zalloc(sizeof (*args), KM_SLEEP);
222
223 if ((uap->flags & MS_DATA) &&
224 (uap->datalen != 0 && uap->dataptr != NULL)) {
225 /* copy in the arguments */
226 if (error = sdev_copyin_mountargs(uap, args))
227 goto cleanup;
228 }
229
230 /*
231 * Sanity check the backing store
232 */
233 if (args->sdev_attrdir) {
234 /* user supplied an attribute store */
235 if (error = lookupname((char *)(uintptr_t)args->sdev_attrdir,
236 UIO_USERSPACE, FOLLOW, NULLVPP, &avp)) {
237 cmn_err(CE_NOTE, "/dev fs: lookup on attribute "
238 "directory %s failed",
239 (char *)(uintptr_t)args->sdev_attrdir);
240 goto cleanup;
241 }
242
243 if (avp->v_type != VDIR) {
244 VN_RELE(avp);
245 error = ENOTDIR;
246 goto cleanup;
247 }
248 } else {
249 /* use mountp as the attribute store */
250 avp = mvp;
251 VN_HOLD(avp);
252 }
253
254 mutex_enter(&sdev_lock);
255
256 /*
257 * handling installation
258 */
259 if (uap->flags & MS_REMOUNT) {
260 sdev_data = (struct sdev_data *)vfsp->vfs_data;
261 ASSERT(sdev_data);
262
263 dv = sdev_data->sdev_root;
264 ASSERT(dv == dv->sdev_dotdot);
265
266 /*
267 * mark all existing sdev_nodes (except root node) stale
268 */
269 sdev_stale(dv);
270
271 /* Reset previous mountargs */
272 if (sdev_data->sdev_mountargs) {
273 kmem_free(sdev_data->sdev_mountargs,
274 sizeof (struct sdev_mountargs));
275 }
276 sdev_data->sdev_mountargs = args;
277 args = NULL; /* so it won't be freed below */
278
279 sdev_stale_attrvp = dv->sdev_attrvp;
280 dv->sdev_attrvp = avp;
281 vfsp->vfs_mtime = ddi_get_time();
282
283 mutex_exit(&sdev_lock);
284 goto cleanup; /* we're done */
285 }
286
287 /*
288 * Create and initialize the vfs-private data.
289 */
290 devdev = makedevice(devmajor, devminor);
291 while (vfs_devismounted(devdev)) {
292 devminor = (devminor + 1) & MAXMIN32;
293
294 /*
295 * All the minor numbers are used up.
296 */
297 if (devminor == 0) {
298 mutex_exit(&sdev_lock);
299 VN_RELE(avp);
300 error = ENODEV;
301 goto cleanup;
302 }
303
304 devdev = makedevice(devmajor, devminor);
305 }
306
307 dv = sdev_mkroot(vfsp, devdev, mvp, avp, cr);
308 sdev_data = kmem_zalloc(sizeof (struct sdev_data), KM_SLEEP);
309 vfsp->vfs_dev = devdev;
310 vfsp->vfs_data = (caddr_t)sdev_data;
311 vfsp->vfs_fstype = devtype;
312 vfsp->vfs_bsize = DEV_BSIZE;
313 vfsp->vfs_mtime = ddi_get_time();
314 vfs_make_fsid(&vfsp->vfs_fsid, vfsp->vfs_dev, devtype);
315
316 ASSERT(dv == dv->sdev_dotdot);
317
318 sdev_data->sdev_vfsp = vfsp;
319 sdev_data->sdev_root = dv;
320 sdev_data->sdev_mountargs = args;
321
322 /* get acl flavor from attribute dir */
323 if (VOP_PATHCONF(avp, _PC_ACL_ENABLED, &sdev_data->sdev_acl_flavor,
324 kcred, NULL) != 0 || sdev_data->sdev_acl_flavor == 0)
325 sdev_data->sdev_acl_flavor = _ACL_ACLENT_ENABLED;
326
327 args = NULL; /* so it won't be freed below */
328 sdev_insert_mntinfo(sdev_data);
329 mutex_exit(&sdev_lock);
330
331 if (!SDEV_IS_GLOBAL(dv)) {
332 ASSERT(sdev_origins);
333 dv->sdev_flags &= ~SDEV_GLOBAL;
334 dv->sdev_origin = sdev_origins->sdev_root;
335 } else {
336 sdev_ncache_setup();
337 rw_enter(&dv->sdev_contents, RW_WRITER);
338 sdev_filldir_dynamic(dv);
339 rw_exit(&dv->sdev_contents);
340 }
341
342 sdev_update_timestamps(dv->sdev_attrvp,
343 cr, AT_CTIME|AT_MTIME|AT_ATIME);
344
345 cleanup:
346 if (args)
347 kmem_free(args, sizeof (*args));
348 return (error);
349 }
350
351 /*
352 * unmounting the non-global /dev instances, e.g. when deleting a Kevlar zone.
353 */
354 static int
sdev_unmount(struct vfs * vfsp,int flag,struct cred * cr)355 sdev_unmount(struct vfs *vfsp, int flag, struct cred *cr)
356 {
357 struct sdev_node *dv;
358 int error;
359 struct sdev_data *sdev_data, *prev, *next;
360
361 /*
362 * enforce the security policies
363 */
364 if ((secpolicy_fs_unmount(cr, vfsp) != 0) ||
365 (secpolicy_sys_devices(cr) != 0))
366 return (EPERM);
367
368 if (flag & MS_FORCE)
369 return (ENOTSUP);
370
371 mutex_enter(&sdev_lock);
372 dv = VFSTOSDEVFS(vfsp)->sdev_root;
373 ASSERT(dv == dv->sdev_dotdot);
374 if (SDEVTOV(dv)->v_count > 1) {
375 mutex_exit(&sdev_lock);
376 return (EBUSY);
377 }
378
379 /*
380 * global instance remains mounted
381 */
382 if (SDEV_IS_GLOBAL(dv)) {
383 mutex_exit(&sdev_lock);
384 return (EBUSY);
385 }
386 mutex_exit(&sdev_lock);
387
388 /* verify the v_count */
389 if ((error = sdev_cleandir(dv, NULL, 0)) != 0) {
390 return (error);
391 }
392 ASSERT(SDEVTOV(dv)->v_count == 1);
393
394 /* release hold on root node and destroy it */
395 SDEV_RELE(dv);
396 dv->sdev_nlink -= 2;
397 sdev_nodedestroy(dv, 0);
398
399 sdev_data = (struct sdev_data *)vfsp->vfs_data;
400 vfsp->vfs_data = (caddr_t)0;
401
402 /*
403 * XXX separate it into sdev_delete_mntinfo() if useful
404 */
405 mutex_enter(&sdev_lock);
406 prev = sdev_data->sdev_prev;
407 next = sdev_data->sdev_next;
408 if (prev)
409 prev->sdev_next = next;
410 else
411 sdev_mntinfo = next;
412 if (next)
413 next->sdev_prev = prev;
414 mutex_exit(&sdev_lock);
415
416 if (sdev_data->sdev_mountargs) {
417 kmem_free(sdev_data->sdev_mountargs,
418 sizeof (struct sdev_mountargs));
419 }
420 kmem_free(sdev_data, sizeof (struct sdev_data));
421 return (0);
422 }
423
424 /*
425 * return root vnode for given vfs
426 */
427 static int
sdev_root(struct vfs * vfsp,struct vnode ** vpp)428 sdev_root(struct vfs *vfsp, struct vnode **vpp)
429 {
430 *vpp = SDEVTOV(VFSTOSDEVFS(vfsp)->sdev_root);
431 VN_HOLD(*vpp);
432 return (0);
433 }
434
435 /*
436 * return 'generic superblock' information to userland.
437 *
438 * not much that we can usefully admit to here
439 */
440 static int
sdev_statvfs(struct vfs * vfsp,struct statvfs64 * sbp)441 sdev_statvfs(struct vfs *vfsp, struct statvfs64 *sbp)
442 {
443 dev32_t d32;
444
445 bzero(sbp, sizeof (*sbp));
446 sbp->f_frsize = sbp->f_bsize = vfsp->vfs_bsize;
447 sbp->f_files = kmem_cache_stat(sdev_node_cache, "alloc");
448
449 /* no illusions that free/avail files is relevant to dev */
450 sbp->f_ffree = 0;
451 sbp->f_favail = 0;
452
453 /* no illusions that blocks are relevant to devfs */
454 sbp->f_bfree = 0;
455 sbp->f_bavail = 0;
456 sbp->f_blocks = 0;
457
458 (void) cmpldev(&d32, vfsp->vfs_dev);
459 sbp->f_fsid = d32;
460 (void) strcpy(sbp->f_basetype, vfssw[devtype].vsw_name);
461 sbp->f_flag = vf_to_stf(vfsp->vfs_flag);
462 sbp->f_namemax = MAXNAMELEN - 1;
463 (void) strcpy(sbp->f_fstr, "dev");
464
465 return (0);
466 }
467
468 static void
sdev_insert_mntinfo(struct sdev_data * data)469 sdev_insert_mntinfo(struct sdev_data *data)
470 {
471 ASSERT(mutex_owned(&sdev_lock));
472 data->sdev_next = sdev_mntinfo;
473 data->sdev_prev = NULL;
474 if (sdev_mntinfo) {
475 sdev_mntinfo->sdev_prev = data;
476 } else {
477 sdev_origins = data;
478 }
479 sdev_mntinfo = data;
480 }
481
482 struct sdev_data *
sdev_find_mntinfo(char * mntpt)483 sdev_find_mntinfo(char *mntpt)
484 {
485 struct sdev_data *mntinfo;
486
487 mutex_enter(&sdev_lock);
488 mntinfo = sdev_mntinfo;
489 while (mntinfo) {
490 if (strcmp(mntpt, mntinfo->sdev_root->sdev_name) == 0) {
491 SDEVTOV(mntinfo->sdev_root)->v_count++;
492 break;
493 }
494 mntinfo = mntinfo->sdev_next;
495 }
496 mutex_exit(&sdev_lock);
497 return (mntinfo);
498 }
499
500 void
sdev_mntinfo_rele(struct sdev_data * mntinfo)501 sdev_mntinfo_rele(struct sdev_data *mntinfo)
502 {
503 mutex_enter(&sdev_lock);
504 SDEVTOV(mntinfo->sdev_root)->v_count--;
505 mutex_exit(&sdev_lock);
506 }
507