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 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * This is the device filesystem.
28 *
29 * It is a combination of a namer to drive autoconfiguration,
30 * plus the access methods for the device drivers of the system.
31 *
32 * The prototype is fairly dependent on specfs for the latter part
33 * of its implementation, though a final version would integrate the two.
34 */
35 #include <sys/types.h>
36 #include <sys/param.h>
37 #include <sys/sysmacros.h>
38 #include <sys/systm.h>
39 #include <sys/kmem.h>
40 #include <sys/time.h>
41 #include <sys/pathname.h>
42 #include <sys/vfs.h>
43 #include <sys/vfs_opreg.h>
44 #include <sys/vnode.h>
45 #include <sys/stat.h>
46 #include <sys/uio.h>
47 #include <sys/stat.h>
48 #include <sys/errno.h>
49 #include <sys/cmn_err.h>
50 #include <sys/cred.h>
51 #include <sys/statvfs.h>
52 #include <sys/mount.h>
53 #include <sys/debug.h>
54 #include <sys/modctl.h>
55 #include <fs/fs_subr.h>
56 #include <sys/fs/dv_node.h>
57 #include <sys/fs/snode.h>
58 #include <sys/sunndi.h>
59 #include <sys/policy.h>
60 #include <sys/sunmdi.h>
61
62 /*
63 * devfs vfs operations.
64 */
65 static int devfs_mount(struct vfs *, struct vnode *, struct mounta *,
66 struct cred *);
67 static int devfs_unmount(struct vfs *, int, struct cred *);
68 static int devfs_root(struct vfs *, struct vnode **);
69 static int devfs_statvfs(struct vfs *, struct statvfs64 *);
70 static int devfs_mountroot(struct vfs *, enum whymountroot);
71
72 static int devfsinit(int, char *);
73
74 static vfsdef_t devfs_vfssw = {
75 VFSDEF_VERSION,
76 "devfs", /* type name string */
77 devfsinit, /* init routine */
78 0, /* flags */
79 NULL /* mount options table prototype */
80 };
81
82 static kmutex_t devfs_lock; /* protects global data */
83 static int devfstype; /* fstype */
84 static dev_t devfsdev; /* the fictious 'device' we live on */
85 static struct devfs_data *devfs_mntinfo; /* linked list of instances */
86
87 /*
88 * Module linkage information
89 */
90 static struct modlfs modlfs = {
91 &mod_fsops, "devices filesystem", &devfs_vfssw
92 };
93
94 static struct modlinkage modlinkage = {
95 MODREV_1, { (void *)&modlfs, NULL }
96 };
97
98 int
99 _init(void)
100 {
101 int e;
102
103 mutex_init(&devfs_lock, "devfs lock", MUTEX_DEFAULT, NULL);
104 dv_node_cache_init();
105 if ((e = mod_install(&modlinkage)) != 0) {
106 dv_node_cache_fini();
107 mutex_destroy(&devfs_lock);
108 return (e);
109 }
110 dcmn_err(("devfs loaded\n"));
111 return (0);
112 }
113
114 int
115 _fini(void)
116 {
117 return (EBUSY);
118 }
119
120 int
121 _info(struct modinfo *modinfop)
122 {
123 return (mod_info(&modlinkage, modinfop));
124 }
125
126 /*ARGSUSED1*/
127 static int
128 devfsinit(int fstype, char *name)
129 {
130 static const fs_operation_def_t devfs_vfsops_template[] = {
131 { VFSNAME_MOUNT, { .vfs_mount = devfs_mount } },
132 { VFSNAME_UNMOUNT, { .vfs_unmount = devfs_unmount } },
133 { VFSNAME_ROOT, { .vfs_root = devfs_root } },
134 { VFSNAME_STATVFS, { .vfs_statvfs = devfs_statvfs } },
135 { VFSNAME_SYNC, { .vfs_sync = fs_sync } },
136 { VFSNAME_MOUNTROOT, { .vfs_mountroot = devfs_mountroot } },
137 { NULL, { NULL } }
138 };
139 int error;
140 int dev;
141 extern major_t getudev(void); /* gack - what a function */
142
143 devfstype = fstype;
144 /*
145 * Associate VFS ops vector with this fstype
146 */
147 error = vfs_setfsops(fstype, devfs_vfsops_template, NULL);
148 if (error != 0) {
149 cmn_err(CE_WARN, "devfsinit: bad vfs ops template");
150 return (error);
151 }
152
153 error = vn_make_ops("dev fs", dv_vnodeops_template, &dv_vnodeops);
154 if (error != 0) {
155 (void) vfs_freevfsops_by_type(fstype);
156 cmn_err(CE_WARN, "devfsinit: bad vnode ops template");
157 return (error);
158 }
159
160 /*
161 * Invent a dev_t (sigh).
162 */
163 if ((dev = getudev()) == DDI_MAJOR_T_NONE) {
164 cmn_err(CE_NOTE, "%s: can't get unique dev", devfs_vfssw.name);
165 dev = 0;
166 }
167 devfsdev = makedevice(dev, 0);
168
169 return (0);
170 }
171
172 /*
173 * The name of the mount point and the name of the attribute
174 * filesystem are passed down from userland for now.
175 */
176 static int
177 devfs_mount(struct vfs *vfsp, struct vnode *mvp, struct mounta *uap,
178 struct cred *cr)
179 {
180 struct devfs_data *devfs_data;
181 struct vnode *avp;
182 struct dv_node *dv;
183 struct vattr va;
184
185 dcmn_err(("devfs_mount\n"));
186
187 if (secpolicy_fs_mount(cr, mvp, vfsp) != 0)
188 return (EPERM);
189
190 /*
191 * check that the mount point is sane
192 */
193 if (mvp->v_type != VDIR)
194 return (ENOTDIR);
195
196 ASSERT(uap->flags & MS_SYSSPACE);
197 /*
198 * Devfs can only be mounted from kernel during boot.
199 * avp is the existing /devices, the same as the mount point.
200 */
201 avp = mvp;
202
203 /*
204 * Create and initialize the vfs-private data.
205 * This includes a hand-crafted root vnode (we build
206 * this here mostly so that traverse() doesn't sleep
207 * in VFS_ROOT()).
208 */
209 mutex_enter(&devfs_lock);
210 ASSERT(devfs_mntinfo == NULL);
211 dv = dv_mkroot(vfsp, devfsdev);
212 dv->dv_attrvp = avp; /* attribute root vp */
213
214 ASSERT(dv == dv->dv_dotdot);
215
216 devfs_data = kmem_zalloc(sizeof (struct devfs_data), KM_SLEEP);
217 devfs_data->devfs_vfsp = vfsp;
218 devfs_data->devfs_root = dv;
219
220 vfsp->vfs_data = (caddr_t)devfs_data;
221 vfsp->vfs_fstype = devfstype;
222 vfsp->vfs_dev = devfsdev;
223 vfsp->vfs_bsize = DEV_BSIZE;
224 vfsp->vfs_mtime = ddi_get_time();
225 vfs_make_fsid(&vfsp->vfs_fsid, vfsp->vfs_dev, devfstype);
226
227 /* We're there. */
228 devfs_mntinfo = devfs_data;
229 mutex_exit(&devfs_lock);
230
231 va.va_mask = AT_ATIME|AT_MTIME;
232 gethrestime(&va.va_atime);
233 gethrestime(&va.va_mtime);
234 (void) VOP_SETATTR(DVTOV(dv), &va, 0, cr, NULL);
235 return (0);
236 }
237
238
239 /*
240 * We never unmount devfs in a real production system.
241 */
242 /*ARGSUSED*/
243 static int
244 devfs_unmount(struct vfs *vfsp, int flag, struct cred *cr)
245 {
246 return (EBUSY);
247 }
248
249 /*
250 * return root vnode for given vfs
251 */
252 static int
253 devfs_root(struct vfs *vfsp, struct vnode **vpp)
254 {
255 dcmn_err(("devfs_root\n"));
256 *vpp = DVTOV(VFSTODVFS(vfsp)->devfs_root);
257 VN_HOLD(*vpp);
258 return (0);
259 }
260
261 /*
262 * return 'generic superblock' information to userland.
263 *
264 * not much that we can usefully admit to here
265 */
266 static int
267 devfs_statvfs(struct vfs *vfsp, struct statvfs64 *sbp)
268 {
269 extern kmem_cache_t *dv_node_cache;
270
271 dev32_t d32;
272
273 dcmn_err(("devfs_statvfs\n"));
274 bzero(sbp, sizeof (*sbp));
275 sbp->f_frsize = sbp->f_bsize = vfsp->vfs_bsize;
276 /*
277 * We could compute the number of devfsnodes here .. but since
278 * it's dynamic anyway, it's not clear how useful this is.
279 */
280 sbp->f_files = kmem_cache_stat(dv_node_cache, "alloc");
281
282 /* no illusions that free/avail files is relevant to devfs */
283 sbp->f_ffree = 0;
284 sbp->f_favail = 0;
285
286 /* no illusions that blocks are relevant to devfs */
287 sbp->f_bfree = 0;
288 sbp->f_bavail = 0;
289 sbp->f_blocks = 0;
290
291 (void) cmpldev(&d32, vfsp->vfs_dev);
292 sbp->f_fsid = d32;
293 (void) strcpy(sbp->f_basetype, vfssw[devfstype].vsw_name);
294 sbp->f_flag = vf_to_stf(vfsp->vfs_flag);
295 sbp->f_namemax = MAXNAMELEN - 1;
296 (void) strcpy(sbp->f_fstr, "devices");
297
298 return (0);
299 }
300
301 /*
302 * devfs always mount after root is mounted, so this should never
303 * be invoked.
304 */
305 /*ARGSUSED*/
306 static int
307 devfs_mountroot(struct vfs *vfsp, enum whymountroot why)
308 {
309 dcmn_err(("devfs_mountroot\n"));
310
311 return (EINVAL);
312 }
313
314 struct dv_node *
315 devfs_dip_to_dvnode(dev_info_t *dip)
316 {
317 char *dirpath;
318 struct vnode *dirvp;
319
320 ASSERT(dip != NULL);
321
322 /* no-op if devfs not mounted yet */
323 if (devfs_mntinfo == NULL)
324 return (NULL);
325
326 /*
327 * The lookupname below only looks up cached dv_nodes
328 * because devfs_clean_key is set in thread specific data.
329 */
330 dirpath = kmem_alloc(MAXPATHLEN, KM_SLEEP);
331 (void) ddi_pathname(dip, dirpath);
332 if (devfs_lookupname(dirpath, NULLVPP, &dirvp)) {
333 dcmn_err(("directory %s not found\n", dirpath));
334 kmem_free(dirpath, MAXPATHLEN);
335 return (NULL);
336 }
337
338 kmem_free(dirpath, MAXPATHLEN);
339 return (VTODV(dirvp));
340 }
341
342 /*
343 * If DV_CLEAN_FORCE devfs_clean is issued with a dip that is not the root
344 * and not a vHCI we also need to clean any vHCI branches because they
345 * may contain pHCI nodes. A detach_node() of a pHCI will fail if its
346 * mdi_devi_offline() fails, and the mdi_devi_offline() of the last
347 * pHCI will fail unless an ndi_devi_offline() of the Client nodes under
348 * the vHCI is successful - which requires a clean vHCI branch to removed
349 * the devi_refs associated with devfs vnodes.
350 */
351 static int
352 devfs_clean_vhci(dev_info_t *dip, void *args)
353 {
354 struct dv_node *dvp;
355 uint_t flags = (uint_t)(uintptr_t)args;
356
357 (void) tsd_set(devfs_clean_key, (void *)1);
358 dvp = devfs_dip_to_dvnode(dip);
359 if (dvp) {
360 (void) dv_cleandir(dvp, NULL, flags);
361 VN_RELE(DVTOV(dvp));
362 }
363 (void) tsd_set(devfs_clean_key, NULL);
364 return (DDI_WALK_CONTINUE);
365 }
366
367 /*
368 * devfs_clean()
369 *
370 * Destroy unreferenced dv_node's and detach devices.
371 *
372 * devfs_clean will try its best to clean up unused nodes. It is
373 * no longer valid to assume that just because devfs_clean fails,
374 * the device is not removable. This is because device contracts
375 * can result in userland processes releasing a device during the
376 * device offline process in the kernel. Thus it is no longer
377 * correct to fail an offline just because devfs_clean finds
378 * referenced dv_nodes. To enforce this, devfs_clean() always
379 * returns success i.e. 0.
380 *
381 * devfs_clean() may return before removing all possible nodes if
382 * we cannot acquire locks in areas of the code where potential for
383 * deadlock exists (see comments in dv_find() and dv_cleandir() for
384 * examples of this).
385 *
386 * devfs caches unreferenced dv_node to speed by the performance
387 * of ls, find, etc. devfs_clean() is invoked to cleanup cached
388 * dv_nodes to reclaim memory as well as to facilitate device
389 * removal (dv_node reference devinfo nodes, which prevents driver
390 * detach).
391 *
392 * If a shell parks in a /devices directory, the dv_node will be
393 * held, preventing the corresponding device to be detached.
394 * This would be a denial of service against DR. To prevent this,
395 * DR code calls devfs_clean() with the DV_CLEAN_FORCE flag.
396 * The dv_cleandir() implementation does the right thing to ensure
397 * successful DR.
398 */
399 int
400 devfs_clean(dev_info_t *dip, char *devnm, uint_t flags)
401 {
402 struct dv_node *dvp;
403
404 dcmn_err(("devfs_unconfigure: dip = 0x%p, flags = 0x%x",
405 (void *)dip, flags));
406
407 /* avoid recursion back into the device tree */
408 (void) tsd_set(devfs_clean_key, (void *)1);
409 dvp = devfs_dip_to_dvnode(dip);
410 if (dvp == NULL) {
411 (void) tsd_set(devfs_clean_key, NULL);
412 return (0);
413 }
414
415 (void) dv_cleandir(dvp, devnm, flags);
416 (void) tsd_set(devfs_clean_key, NULL);
417 VN_RELE(DVTOV(dvp));
418
419 /*
420 * If we are doing a DV_CLEAN_FORCE, and we did not start at the
421 * root, and we did not start at a vHCI node then clean vHCI
422 * branches too. Failure to clean vHCI branch does not cause EBUSY.
423 *
424 * Also, to accommodate nexus callers that clean 'self' to DR 'child'
425 * (like pcihp) we clean vHCIs even when dv_cleandir() of dip branch
426 * above fails - this prevents a busy DR 'child' sibling from causing
427 * the DR of 'child' to fail because a vHCI branch was not cleaned.
428 */
429 if ((flags & DV_CLEAN_FORCE) && (dip != ddi_root_node()) &&
430 (mdi_component_is_vhci(dip, NULL) != MDI_SUCCESS)) {
431 /*
432 * NOTE: for backport the following is recommended
433 * (void) devfs_clean_vhci(scsi_vhci_dip,
434 * (void *)(uintptr_t)flags);
435 */
436 mdi_walk_vhcis(devfs_clean_vhci, (void *)(uintptr_t)flags);
437 }
438
439 return (0);
440 }
441
442 /*
443 * lookup a devfs relative pathname, returning held vnodes for the final
444 * component and the containing directory (if requested).
445 *
446 * NOTE: We can't use lookupname because this would use the current
447 * processes credentials (CRED) in the call lookuppnvp instead
448 * of kcred. It also does not give you the flexibility so
449 * specify the directory to start the resolution in (devicesdir).
450 */
451 int
452 devfs_lookupname(
453 char *pathname, /* user pathname */
454 vnode_t **dirvpp, /* ret for ptr to parent dir vnode */
455 vnode_t **compvpp) /* ret for ptr to component vnode */
456 {
457 struct pathname pn;
458 int error;
459
460 ASSERT(devicesdir); /* devfs must be initialized */
461 ASSERT(pathname); /* must have some path */
462
463 if (error = pn_get(pathname, UIO_SYSSPACE, &pn))
464 return (error);
465
466 /* make the path relative to /devices. */
467 pn_skipslash(&pn);
468 if (pn_pathleft(&pn) == 0) {
469 /* all we had was "\0" or "/" (which skipslash skiped) */
470 if (dirvpp)
471 *dirvpp = NULL;
472 if (compvpp) {
473 VN_HOLD(devicesdir);
474 *compvpp = devicesdir;
475 }
476 } else {
477 /*
478 * Use devfs lookup to resolve pathname to the vnode for
479 * the device via relative lookup in devfs. Extra holds for
480 * using devicesdir as directory we are searching and for
481 * being our root without being == rootdir.
482 */
483 VN_HOLD(devicesdir);
484 VN_HOLD(devicesdir);
485 error = lookuppnvp(&pn, NULL, FOLLOW, dirvpp, compvpp,
486 devicesdir, devicesdir, kcred);
487 }
488 pn_free(&pn);
489
490 return (error);
491 }
492
493 /*
494 * Given a devfs path (without the /devices prefix), walk
495 * the dv_node sub-tree rooted at the path.
496 */
497 int
498 devfs_walk(
499 char *path,
500 void (*callback)(struct dv_node *, void *),
501 void *arg)
502 {
503 char *dirpath, *devnm;
504 struct vnode *dirvp;
505
506 ASSERT(path && callback);
507
508 if (*path != '/' || devfs_mntinfo == NULL)
509 return (ENXIO);
510
511 dcmn_err(("devfs_walk: path = %s", path));
512
513 dirpath = kmem_alloc(MAXPATHLEN, KM_SLEEP);
514
515 (void) snprintf(dirpath, MAXPATHLEN, "/devices%s", path);
516
517 devnm = strrchr(dirpath, '/');
518
519 ASSERT(devnm);
520
521 *devnm++ = '\0';
522
523 if (lookupname(dirpath, UIO_SYSSPACE, 0, NULL, &dirvp)) {
524 dcmn_err(("directory %s not found\n", dirpath));
525 kmem_free(dirpath, MAXPATHLEN);
526 return (ENXIO);
527 }
528
529 /*
530 * if path == "/", visit the root dv_node
531 */
532 if (*devnm == '\0') {
533 callback(VTODV(dirvp), arg);
534 devnm = NULL;
535 }
536
537 dv_walk(VTODV(dirvp), devnm, callback, arg);
538
539 VN_RELE(dirvp);
540
541 kmem_free(dirpath, MAXPATHLEN);
542
543 return (0);
544 }
545
546 int
547 devfs_devpolicy(vnode_t *vp, devplcy_t **dpp)
548 {
549 struct vnode *rvp;
550 struct dv_node *dvp;
551 int rval = -1;
552
553 /* fail if devfs not mounted yet */
554 if (devfs_mntinfo == NULL)
555 return (rval);
556
557 if (VOP_REALVP(vp, &rvp, NULL) == 0 && vn_matchops(rvp, dv_vnodeops)) {
558 dvp = VTODV(rvp);
559 rw_enter(&dvp->dv_contents, RW_READER);
560 if (dvp->dv_priv) {
561 dphold(dvp->dv_priv);
562 *dpp = dvp->dv_priv;
563 rval = 0;
564 }
565 rw_exit(&dvp->dv_contents);
566 }
567 return (rval);
568 }