1/* $NetBSD: ptyfs_vfsops.c,v 1.55 2014/10/21 16:05:01 christos Exp $ */
2
3/*
4 * Copyright (c) 1992, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
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 */
35
36/*
37 * Pseudo-tty Filesystem
38 */
39
40#include <sys/cdefs.h>
41__KERNEL_RCSID(0, "$NetBSD: ptyfs_vfsops.c,v 1.55 2014/10/21 16:05:01 christos Exp $");
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/sysctl.h>
46#include <sys/conf.h>
47#include <sys/proc.h>
48#include <sys/vnode.h>
49#include <sys/mount.h>
50#include <sys/namei.h>
51#include <sys/stat.h>
52#include <sys/dirent.h>
53#include <sys/malloc.h>
54#include <sys/syslog.h>
55#include <sys/select.h>
56#include <sys/filedesc.h>
57#include <sys/tty.h>
58#include <sys/pty.h>
59#include <sys/kauth.h>
60#include <sys/module.h>
61
62#include <fs/ptyfs/ptyfs.h>
63#include <miscfs/genfs/genfs.h>
64#include <miscfs/specfs/specdev.h>
65
66MODULE(MODULE_CLASS_VFS, ptyfs, NULL);
67
68MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures");
69MALLOC_JUSTDEFINE(M_PTYFSTMP, "ptyfs temp", "ptyfs temporary structures");
70
71VFS_PROTOS(ptyfs);
72
73static struct sysctllog *ptyfs_sysctl_log;
74
75static int ptyfs__allocvp(struct mount *, struct lwp *, struct vnode **,
76 dev_t, char);
77static int ptyfs__makename(struct mount *, struct lwp *, char *, size_t,
78 dev_t, char);
79static void ptyfs__getvattr(struct mount *, struct lwp *, struct vattr *);
80static int ptyfs__getmp(struct lwp *, struct mount **);
81
82/*
83 * ptm glue: When we mount, we make ptm point to us.
84 */
85struct ptm_pty *ptyfs_save_ptm;
86static int ptyfs_count;
87
88static TAILQ_HEAD(, ptyfsmount) ptyfs_head;
89
90struct ptm_pty ptm_ptyfspty = {
91 ptyfs__allocvp,
92 ptyfs__makename,
93 ptyfs__getvattr,
94 ptyfs__getmp,
95};
96
97static int
98ptyfs__getmp(struct lwp *l, struct mount **mpp)
99{
100 struct cwdinfo *cwdi = l->l_proc->p_cwdi;
101 struct mount *mp;
102 struct ptyfsmount *pmnt;
103
104 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) {
105 mp = pmnt->pmnt_mp;
106 if (cwdi->cwdi_rdir == NULL)
107 goto ok;
108
109 if (vn_isunder(mp->mnt_vnodecovered, cwdi->cwdi_rdir, l))
110 goto ok;
111 }
112 *mpp = NULL;
113 return EOPNOTSUPP;
114ok:
115 *mpp = mp;
116 return 0;
117}
118
119static const char *
120ptyfs__getpath(struct lwp *l, const struct mount *mp)
121{
122#define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
123 struct cwdinfo *cwdi = l->l_proc->p_cwdi;
124 char *buf;
125 const char *rv;
126 size_t len;
127 char *bp;
128 int error;
129
130 rv = mp->mnt_stat.f_mntonname;
131 if (cwdi->cwdi_rdir == NULL)
132 return rv;
133
134 buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
135 bp = buf + MAXBUF;
136 *--bp = '\0';
137 error = getcwd_common(mp->mnt_vnodecovered, cwdi->cwdi_rdir, &bp,
138 buf, MAXBUF / 2, 0, l);
139 if (error) { /* Mount point is out of rdir */
140 rv = NULL;
141 goto out;
142 }
143
144 len = strlen(bp);
145 if (len < sizeof(mp->mnt_stat.f_mntonname)) /* XXX */
146 rv += strlen(rv) - len;
147out:
148 free(buf, M_TEMP);
149 return rv;
150}
151
152static int
153ptyfs__makename(struct mount *mp, struct lwp *l, char *tbuf, size_t bufsiz,
154 dev_t dev, char ms)
155{
156 size_t len;
157 const char *np;
158 int pty = minor(dev);
159
160 switch (ms) {
161 case 'p':
162 /* We don't provide access to the master, should we? */
163 len = snprintf(tbuf, bufsiz, "/dev/null");
164 break;
165 case 't':
166 /*
167 * We support traditional ptys, so we can get here,
168 * if pty had been opened before PTYFS was mounted,
169 * or was opened through /dev/ptyXX devices.
170 * Return it only outside chroot for more security .
171 */
172 if (l->l_proc->p_cwdi->cwdi_rdir == NULL
173 && ptyfs_save_ptm != NULL
174 && ptyfs_next_active(mp, pty) != pty)
175 return (*ptyfs_save_ptm->makename)(mp, l,
176 tbuf, bufsiz, dev, ms);
177
178 np = ptyfs__getpath(l, mp);
179 if (np == NULL)
180 return EOPNOTSUPP;
181 len = snprintf(tbuf, bufsiz, "%s/%llu", np,
182 (unsigned long long)minor(dev));
183 break;
184 default:
185 return EINVAL;
186 }
187
188 return len >= bufsiz ? ENOSPC : 0;
189}
190
191
192static int
193/*ARGSUSED*/
194ptyfs__allocvp(struct mount *mp, struct lwp *l, struct vnode **vpp,
195 dev_t dev, char ms)
196{
197 int error;
198 ptyfstype type;
199
200 switch (ms) {
201 case 'p':
202 type = PTYFSptc;
203 break;
204 case 't':
205 type = PTYFSpts;
206 break;
207 default:
208 return EINVAL;
209 }
210
211 error = ptyfs_allocvp(mp, vpp, type, minor(dev));
212 if (error)
213 return error;
214 error = vn_lock(*vpp, LK_EXCLUSIVE);
215 if (error) {
216 vrele(*vpp);
217 *vpp = NULL;
218 return error;
219 }
220 if (type == PTYFSptc)
221 ptyfs_set_active(mp, minor(dev));
222 return 0;
223}
224
225
226static void
227ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
228{
229 struct ptyfsmount *pmnt = VFSTOPTY(mp);
230 vattr_null(vattr);
231 /* get real uid */
232 vattr->va_uid = kauth_cred_getuid(l->l_cred);
233 vattr->va_gid = pmnt->pmnt_gid;
234 vattr->va_mode = pmnt->pmnt_mode;
235}
236
237
238void
239ptyfs_init(void)
240{
241
242 TAILQ_INIT(&ptyfs_head);
243 malloc_type_attach(M_PTYFSMNT);
244 malloc_type_attach(M_PTYFSTMP);
245 ptyfs_hashinit();
246}
247
248void
249ptyfs_reinit(void)
250{
251
252}
253
254void
255ptyfs_done(void)
256{
257
258 ptyfs_hashdone();
259 malloc_type_detach(M_PTYFSTMP);
260 malloc_type_detach(M_PTYFSMNT);
261}
262
263#define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
264/*
265 * Mount the Pseudo tty params filesystem
266 */
267int
268ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
269{
270 struct lwp *l = curlwp;
271 int error = 0;
272 struct ptyfsmount *pmnt;
273 struct ptyfs_args *args = data;
274
275 if (args == NULL)
276 return EINVAL;
277 if (*data_len != sizeof *args) {
278 if (*data_len != OSIZE || args->version >= PTYFS_ARGSVERSION)
279 return EINVAL;
280 }
281
282 if (UIO_MX & (UIO_MX - 1)) {
283 log(LOG_ERR, "ptyfs: invalid directory entry size");
284 return EINVAL;
285 }
286
287 if (mp->mnt_flag & MNT_GETARGS) {
288 pmnt = VFSTOPTY(mp);
289 if (pmnt == NULL)
290 return EIO;
291 args->mode = pmnt->pmnt_mode;
292 args->gid = pmnt->pmnt_gid;
293 if (args->version >= PTYFS_ARGSVERSION) {
294 args->flags = pmnt->pmnt_flags;
295 *data_len = sizeof *args;
296 } else {
297 *data_len = OSIZE;
298 }
299 return 0;
300 }
301
302#if 0
303 /* Don't allow more than one mount */
304 if (ptyfs_count)
305 return EBUSY;
306#endif
307
308 if (mp->mnt_flag & MNT_UPDATE)
309 return EOPNOTSUPP;
310
311 if (args->version > PTYFS_ARGSVERSION)
312 return EINVAL;
313
314 pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
315
316 mp->mnt_data = pmnt;
317 mutex_init(&pmnt->pmnt_lock, MUTEX_DEFAULT, IPL_NONE);
318 pmnt->pmnt_gid = args->gid;
319 pmnt->pmnt_mode = args->mode;
320 if (args->version >= PTYFS_ARGSVERSION)
321 pmnt->pmnt_flags = args->flags;
322 else
323 pmnt->pmnt_flags = 0;
324 pmnt->pmnt_bitmap_size = 0;
325 pmnt->pmnt_bitmap = NULL;
326 mp->mnt_flag |= MNT_LOCAL;
327 vfs_getnewfsid(mp);
328
329 if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
330 UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
331 free(pmnt, M_PTYFSMNT);
332 return error;
333 }
334
335 pmnt->pmnt_mp = mp;
336 TAILQ_INSERT_TAIL(&ptyfs_head, pmnt, pmnt_le);
337 if (ptyfs_count++ == 0) {
338 /* Point pty access to us */
339 ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
340 }
341 return 0;
342}
343
344/*ARGSUSED*/
345int
346ptyfs_start(struct mount *mp, int flags)
347{
348 return 0;
349}
350
351/*ARGSUSED*/
352int
353ptyfs_unmount(struct mount *mp, int mntflags)
354{
355 int error;
356 int flags = 0;
357 struct ptyfsmount *pmnt;
358
359 if (mntflags & MNT_FORCE)
360 flags |= FORCECLOSE;
361
362 if ((error = vflush(mp, 0, flags)) != 0)
363 return error;
364
365 ptyfs_count--;
366 if (ptyfs_count == 0) {
367 /* Restore where pty access was pointing */
368 (void)pty_sethandler(ptyfs_save_ptm);
369 ptyfs_save_ptm = NULL;
370 }
371 TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) {
372 if (pmnt->pmnt_mp == mp) {
373 TAILQ_REMOVE(&ptyfs_head, pmnt, pmnt_le);
374 break;
375 }
376 }
377
378 /*
379 * Finally, throw away the ptyfsmount structure
380 */
381 if (pmnt->pmnt_bitmap_size > 0)
382 kmem_free(pmnt->pmnt_bitmap, pmnt->pmnt_bitmap_size);
383 mutex_destroy(&pmnt->pmnt_lock);
384 free(mp->mnt_data, M_PTYFSMNT);
385 mp->mnt_data = NULL;
386
387 return 0;
388}
389
390int
391ptyfs_root(struct mount *mp, struct vnode **vpp)
392{
393 int error;
394
395 /* setup "." */
396 error = ptyfs_allocvp(mp, vpp, PTYFSroot, 0);
397 if (error)
398 return error;
399 error = vn_lock(*vpp, LK_EXCLUSIVE);
400 if (error) {
401 vrele(*vpp);
402 *vpp = NULL;
403 return error;
404 }
405 return 0;
406}
407
408/*ARGSUSED*/
409int
410ptyfs_sync(struct mount *mp, int waitfor,
411 kauth_cred_t uc)
412{
413 return 0;
414}
415
416/*
417 * Initialize this vnode / ptynode pair.
418 * Only for the slave side of a pty, caller assures
419 * no other thread will try to load this node.
420 */
421int
422ptyfs_loadvnode(struct mount *mp, struct vnode *vp,
423 const void *key, size_t key_len, const void **new_key)
424{
425 struct ptyfskey pkey;
426 struct ptyfsnode *ptyfs;
427
428 KASSERT(key_len == sizeof(pkey));
429 memcpy(&pkey, key, key_len);
430
431 ptyfs = ptyfs_get_node(pkey.ptk_type, pkey.ptk_pty);
432 KASSERT(memcmp(&ptyfs->ptyfs_key, &pkey, sizeof(pkey)) == 0);
433
434 switch (pkey.ptk_type) {
435 case PTYFSroot: /* /pts = dr-xr-xr-x */
436 vp->v_type = VDIR;
437 vp->v_vflag = VV_ROOT;
438 break;
439
440 case PTYFSpts: /* /pts/N = cxxxxxxxxx */
441 case PTYFSptc: /* controlling side = cxxxxxxxxx */
442 vp->v_type = VCHR;
443 spec_node_init(vp, PTYFS_MAKEDEV(ptyfs));
444 break;
445 default:
446 panic("ptyfs_loadvnode");
447 }
448
449 vp->v_tag = VT_PTYFS;
450 vp->v_op = ptyfs_vnodeop_p;
451 vp->v_data = ptyfs;
452 uvm_vnp_setsize(vp, 0);
453 *new_key = &ptyfs->ptyfs_key;
454 return 0;
455}
456
457/*
458 * Kernfs flat namespace lookup.
459 * Currently unsupported.
460 */
461/*ARGSUSED*/
462int
463ptyfs_vget(struct mount *mp, ino_t ino,
464 struct vnode **vpp)
465{
466 return EOPNOTSUPP;
467}
468
469extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
470
471const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
472 &ptyfs_vnodeop_opv_desc,
473 NULL,
474};
475
476struct vfsops ptyfs_vfsops = {
477 .vfs_name = MOUNT_PTYFS,
478 .vfs_min_mount_data = sizeof (struct ptyfs_args),
479 .vfs_mount = ptyfs_mount,
480 .vfs_start = ptyfs_start,
481 .vfs_unmount = ptyfs_unmount,
482 .vfs_root = ptyfs_root,
483 .vfs_quotactl = (void *)eopnotsupp,
484 .vfs_statvfs = genfs_statvfs,
485 .vfs_sync = ptyfs_sync,
486 .vfs_vget = ptyfs_vget,
487 .vfs_loadvnode = ptyfs_loadvnode,
488 .vfs_fhtovp = (void *)eopnotsupp,
489 .vfs_vptofh = (void *)eopnotsupp,
490 .vfs_init = ptyfs_init,
491 .vfs_reinit = ptyfs_reinit,
492 .vfs_done = ptyfs_done,
493 .vfs_snapshot = (void *)eopnotsupp,
494 .vfs_extattrctl = (void *)eopnotsupp,
495 .vfs_suspendctl = (void *)eopnotsupp,
496 .vfs_renamelock_enter = genfs_renamelock_enter,
497 .vfs_renamelock_exit = genfs_renamelock_exit,
498 .vfs_fsync = (void *)eopnotsupp,
499 .vfs_opv_descs = ptyfs_vnodeopv_descs
500};
501
502static int
503ptyfs_modcmd(modcmd_t cmd, void *arg)
504{
505 int error;
506
507 switch (cmd) {
508 case MODULE_CMD_INIT:
509 error = vfs_attach(&ptyfs_vfsops);
510 if (error != 0)
511 break;
512 sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
513 CTLFLAG_PERMANENT,
514 CTLTYPE_NODE, "ptyfs",
515 SYSCTL_DESCR("Pty file system"),
516 NULL, 0, NULL, 0,
517 CTL_VFS, 23, CTL_EOL);
518 /*
519 * XXX the "23" above could be dynamic, thereby eliminating
520 * one more instance of the "number to vfs" mapping problem,
521 * but "23" is the order as taken from sys/mount.h
522 */
523 break;
524 case MODULE_CMD_FINI:
525 error = vfs_detach(&ptyfs_vfsops);
526 if (error != 0)
527 break;
528 sysctl_teardown(&ptyfs_sysctl_log);
529 break;
530 default:
531 error = ENOTTY;
532 break;
533 }
534
535 return (error);
536}
537