ptyfs_vfsops.c revision 1.54 
1/*	$NetBSD: ptyfs_vfsops.c,v 1.54 2014/10/15 15:00:03 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 1.54 2014/10/15 15:00:03 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	/* Activate node only after we have grabbed device. */
221	if (type == PTYFSpts)
222		ptyfs_set_active(mp, minor(dev));
223	return 0;
224}
225
226
227static void
228ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
229{
230	struct ptyfsmount *pmnt = VFSTOPTY(mp);
231	vattr_null(vattr);
232	/* get real uid */
233	vattr->va_uid = kauth_cred_getuid(l->l_cred);
234	vattr->va_gid = pmnt->pmnt_gid;
235	vattr->va_mode = pmnt->pmnt_mode;
236}
237
238
239void
240ptyfs_init(void)
241{
242
243	TAILQ_INIT(&ptyfs_head);
244	malloc_type_attach(M_PTYFSMNT);
245	malloc_type_attach(M_PTYFSTMP);
246	ptyfs_hashinit();
247}
248
249void
250ptyfs_reinit(void)
251{
252
253}
254
255void
256ptyfs_done(void)
257{
258
259	ptyfs_hashdone();
260	malloc_type_detach(M_PTYFSTMP);
261	malloc_type_detach(M_PTYFSMNT);
262}
263
264#define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
265/*
266 * Mount the Pseudo tty params filesystem
267 */
268int
269ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
270{
271	struct lwp *l = curlwp;
272	int error = 0;
273	struct ptyfsmount *pmnt;
274	struct ptyfs_args *args = data;
275
276	if (args == NULL)
277		return EINVAL;
278	if (*data_len != sizeof *args) {
279		if (*data_len != OSIZE || args->version >= PTYFS_ARGSVERSION)
280			return EINVAL;
281	}
282
283	if (UIO_MX & (UIO_MX - 1)) {
284		log(LOG_ERR, "ptyfs: invalid directory entry size");
285		return EINVAL;
286	}
287
288	if (mp->mnt_flag & MNT_GETARGS) {
289		pmnt = VFSTOPTY(mp);
290		if (pmnt == NULL)
291			return EIO;
292		args->mode = pmnt->pmnt_mode;
293		args->gid = pmnt->pmnt_gid;
294		if (args->version >= PTYFS_ARGSVERSION) {
295			args->flags = pmnt->pmnt_flags;
296			*data_len = sizeof *args;
297		} else {
298			*data_len = OSIZE;
299		}
300		return 0;
301	}
302
303#if 0
304	/* Don't allow more than one mount */
305	if (ptyfs_count)
306		return EBUSY;
307#endif
308
309	if (mp->mnt_flag & MNT_UPDATE)
310		return EOPNOTSUPP;
311
312	if (args->version > PTYFS_ARGSVERSION)
313		return EINVAL;
314
315	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
316
317	mp->mnt_data = pmnt;
318	mutex_init(&pmnt->pmnt_lock, MUTEX_DEFAULT, IPL_NONE);
319	pmnt->pmnt_gid = args->gid;
320	pmnt->pmnt_mode = args->mode;
321	if (args->version >= PTYFS_ARGSVERSION)
322		pmnt->pmnt_flags = args->flags;
323	else
324		pmnt->pmnt_flags = 0;
325	pmnt->pmnt_bitmap_size = 0;
326	pmnt->pmnt_bitmap = NULL;
327	mp->mnt_flag |= MNT_LOCAL;
328	vfs_getnewfsid(mp);
329
330	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
331	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
332		free(pmnt, M_PTYFSMNT);
333		return error;
334	}
335
336	pmnt->pmnt_mp = mp;
337	TAILQ_INSERT_TAIL(&ptyfs_head, pmnt, pmnt_le);
338	if (ptyfs_count++ == 0) {
339		/* Point pty access to us */
340		ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
341	}
342	return 0;
343}
344
345/*ARGSUSED*/
346int
347ptyfs_start(struct mount *mp, int flags)
348{
349	return 0;
350}
351
352/*ARGSUSED*/
353int
354ptyfs_unmount(struct mount *mp, int mntflags)
355{
356	int error;
357	int flags = 0;
358	struct ptyfsmount *pmnt;
359
360	if (mntflags & MNT_FORCE)
361		flags |= FORCECLOSE;
362
363	if ((error = vflush(mp, 0, flags)) != 0)
364		return error;
365
366	ptyfs_count--;
367	if (ptyfs_count == 0) {
368		/* Restore where pty access was pointing */
369		(void)pty_sethandler(ptyfs_save_ptm);
370		ptyfs_save_ptm = NULL;
371	}
372	TAILQ_FOREACH(pmnt, &ptyfs_head, pmnt_le) {
373		if (pmnt->pmnt_mp == mp) {
374			TAILQ_REMOVE(&ptyfs_head, pmnt, pmnt_le);
375			break;
376		}
377 	}
378
379	/*
380	 * Finally, throw away the ptyfsmount structure
381	 */
382	if (pmnt->pmnt_bitmap_size > 0)
383		kmem_free(pmnt->pmnt_bitmap, pmnt->pmnt_bitmap_size);
384	mutex_destroy(&pmnt->pmnt_lock);
385	free(mp->mnt_data, M_PTYFSMNT);
386	mp->mnt_data = NULL;
387
388	return 0;
389}
390
391int
392ptyfs_root(struct mount *mp, struct vnode **vpp)
393{
394	int error;
395
396	/* setup "." */
397	error = ptyfs_allocvp(mp, vpp, PTYFSroot, 0);
398	if (error)
399		return error;
400	error = vn_lock(*vpp, LK_EXCLUSIVE);
401	if (error) {
402		vrele(*vpp);
403		*vpp = NULL;
404		return error;
405	}
406	return 0;
407}
408
409/*ARGSUSED*/
410int
411ptyfs_sync(struct mount *mp, int waitfor,
412    kauth_cred_t uc)
413{
414	return 0;
415}
416
417/*
418 * Initialize this vnode / ptynode pair.
419 * Only for the slave side of a pty, caller assures
420 * no other thread will try to load this node.
421 */
422int
423ptyfs_loadvnode(struct mount *mp, struct vnode *vp,
424    const void *key, size_t key_len, const void **new_key)
425{
426	struct ptyfskey pkey;
427	struct ptyfsnode *ptyfs;
428
429	KASSERT(key_len == sizeof(pkey));
430	memcpy(&pkey, key, key_len);
431
432	ptyfs = ptyfs_get_node(pkey.ptk_type, pkey.ptk_pty);
433	KASSERT(memcmp(&ptyfs->ptyfs_key, &pkey, sizeof(pkey)) == 0);
434
435	switch (pkey.ptk_type) {
436	case PTYFSroot:	/* /pts = dr-xr-xr-x */
437		vp->v_type = VDIR;
438		vp->v_vflag = VV_ROOT;
439		break;
440
441	case PTYFSpts:	/* /pts/N = cxxxxxxxxx */
442	case PTYFSptc:	/* controlling side = cxxxxxxxxx */
443		vp->v_type = VCHR;
444		spec_node_init(vp, PTYFS_MAKEDEV(ptyfs));
445		break;
446	default:
447		panic("ptyfs_loadvnode");
448	}
449
450	vp->v_tag = VT_PTYFS;
451	vp->v_op = ptyfs_vnodeop_p;
452	vp->v_data = ptyfs;
453	uvm_vnp_setsize(vp, 0);
454	*new_key = &ptyfs->ptyfs_key;
455	return 0;
456}
457
458/*
459 * Kernfs flat namespace lookup.
460 * Currently unsupported.
461 */
462/*ARGSUSED*/
463int
464ptyfs_vget(struct mount *mp, ino_t ino,
465    struct vnode **vpp)
466{
467	return EOPNOTSUPP;
468}
469
470extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
471
472const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
473	&ptyfs_vnodeop_opv_desc,
474	NULL,
475};
476
477struct vfsops ptyfs_vfsops = {
478	.vfs_name = MOUNT_PTYFS,
479	.vfs_min_mount_data = sizeof (struct ptyfs_args),
480	.vfs_mount = ptyfs_mount,
481	.vfs_start = ptyfs_start,
482	.vfs_unmount = ptyfs_unmount,
483	.vfs_root = ptyfs_root,
484	.vfs_quotactl = (void *)eopnotsupp,
485	.vfs_statvfs = genfs_statvfs,
486	.vfs_sync = ptyfs_sync,
487	.vfs_vget = ptyfs_vget,
488	.vfs_loadvnode = ptyfs_loadvnode,
489	.vfs_fhtovp = (void *)eopnotsupp,
490	.vfs_vptofh = (void *)eopnotsupp,
491	.vfs_init = ptyfs_init,
492	.vfs_reinit = ptyfs_reinit,
493	.vfs_done = ptyfs_done,
494	.vfs_snapshot = (void *)eopnotsupp,
495	.vfs_extattrctl = (void *)eopnotsupp,
496	.vfs_suspendctl = (void *)eopnotsupp,
497	.vfs_renamelock_enter = genfs_renamelock_enter,
498	.vfs_renamelock_exit = genfs_renamelock_exit,
499	.vfs_fsync = (void *)eopnotsupp,
500	.vfs_opv_descs = ptyfs_vnodeopv_descs
501};
502
503static int
504ptyfs_modcmd(modcmd_t cmd, void *arg)
505{
506	int error;
507
508	switch (cmd) {
509	case MODULE_CMD_INIT:
510		error = vfs_attach(&ptyfs_vfsops);
511		if (error != 0)
512			break;
513		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
514			       CTLFLAG_PERMANENT,
515			       CTLTYPE_NODE, "ptyfs",
516			       SYSCTL_DESCR("Pty file system"),
517			       NULL, 0, NULL, 0,
518			       CTL_VFS, 23, CTL_EOL);
519		/*
520		 * XXX the "23" above could be dynamic, thereby eliminating
521		 * one more instance of the "number to vfs" mapping problem,
522		 * but "23" is the order as taken from sys/mount.h
523		 */
524		break;
525	case MODULE_CMD_FINI:
526		error = vfs_detach(&ptyfs_vfsops);
527		if (error != 0)
528			break;
529		sysctl_teardown(&ptyfs_sysctl_log);
530		break;
531	default:
532		error = ENOTTY;
533		break;
534	}
535
536	return (error);
537}
538