ptyfs_vfsops.c revision 1.48 
1/*	$NetBSD: ptyfs_vfsops.c,v 1.48 2014/03/27 17:31:56 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 1.48 2014/03/27 17:31:56 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 *);
80
81/*
82 * ptm glue: When we mount, we make ptm point to us.
83 */
84struct ptm_pty *ptyfs_save_ptm;
85static int ptyfs_count;
86
87struct ptm_pty ptm_ptyfspty = {
88	ptyfs__allocvp,
89	ptyfs__makename,
90	ptyfs__getvattr,
91	NULL
92};
93
94static const char *
95ptyfs__getpath(struct lwp *l, const struct mount *mp)
96{
97#define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
98	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
99	char *buf;
100	const char *rv;
101	size_t len;
102	char *bp;
103	int error;
104
105	rv = mp->mnt_stat.f_mntonname;
106	if (cwdi->cwdi_rdir == NULL)
107		return rv;
108
109	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
110	bp = buf + MAXBUF;
111	*--bp = '\0';
112	error = getcwd_common(mp->mnt_vnodecovered, cwdi->cwdi_rdir, &bp,
113	    buf, MAXBUF / 2, 0, l);
114	if (error) {	/* Mount point is out of rdir */
115		rv = NULL;
116		goto out;
117	}
118
119	len = strlen(bp);
120	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
121		rv += strlen(rv) - len;
122out:
123	free(buf, M_TEMP);
124	return rv;
125}
126
127static int
128ptyfs__makename(struct mount *mp, struct lwp *l, char *tbuf, size_t bufsiz,
129    dev_t dev, char ms)
130{
131	size_t len;
132	const char *np;
133
134	switch (ms) {
135	case 'p':
136		/* We don't provide access to the master, should we? */
137		len = snprintf(tbuf, bufsiz, "/dev/null");
138		break;
139	case 't':
140		np = ptyfs__getpath(l, mp);
141		if (np == NULL)
142			return EOPNOTSUPP;
143		len = snprintf(tbuf, bufsiz, "%s/%llu", np,
144			(unsigned long long)minor(dev));
145		break;
146	default:
147		return EINVAL;
148	}
149
150	return len >= bufsiz ? ENOSPC : 0;
151}
152
153
154static int
155/*ARGSUSED*/
156ptyfs__allocvp(struct mount *mp, struct lwp *l, struct vnode **vpp,
157    dev_t dev, char ms)
158{
159	ptyfstype type;
160
161	switch (ms) {
162	case 'p':
163		type = PTYFSptc;
164		break;
165	case 't':
166		type = PTYFSpts;
167		break;
168	default:
169		return EINVAL;
170	}
171
172	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
173}
174
175
176static void
177ptyfs__getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
178{
179	struct ptyfsmount *pmnt = VFSTOPTY(mp);
180	vattr_null(vattr);
181	/* get real uid */
182	vattr->va_uid = kauth_cred_getuid(l->l_cred);
183	vattr->va_gid = pmnt->pmnt_gid;
184	vattr->va_mode = pmnt->pmnt_mode;
185}
186
187
188void
189ptyfs_init(void)
190{
191
192	malloc_type_attach(M_PTYFSMNT);
193	malloc_type_attach(M_PTYFSTMP);
194	ptyfs_hashinit();
195}
196
197void
198ptyfs_reinit(void)
199{
200	ptyfs_hashreinit();
201}
202
203void
204ptyfs_done(void)
205{
206
207	ptyfs_hashdone();
208	malloc_type_detach(M_PTYFSTMP);
209	malloc_type_detach(M_PTYFSMNT);
210}
211
212#define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
213/*
214 * Mount the Pseudo tty params filesystem
215 */
216int
217ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
218{
219	struct lwp *l = curlwp;
220	int error = 0;
221	struct ptyfsmount *pmnt;
222	struct ptyfs_args *args = data;
223
224	if (*data_len != sizeof *args && *data_len != OSIZE)
225		return EINVAL;
226
227	if (UIO_MX & (UIO_MX - 1)) {
228		log(LOG_ERR, "ptyfs: invalid directory entry size");
229		return EINVAL;
230	}
231
232	if (mp->mnt_flag & MNT_GETARGS) {
233		pmnt = VFSTOPTY(mp);
234		if (pmnt == NULL)
235			return EIO;
236		args->mode = pmnt->pmnt_mode;
237		args->gid = pmnt->pmnt_gid;
238		if (args->version >= PTYFS_ARGSVERSION) {
239			args->flags = pmnt->pmnt_flags;
240			*data_len = sizeof *args;
241		} else {
242			*data_len = OSIZE;
243		}
244		return 0;
245	}
246
247#if 0
248	/* Don't allow more than one mount */
249	if (ptyfs_count)
250		return EBUSY;
251#endif
252
253	if (mp->mnt_flag & MNT_UPDATE)
254		return EOPNOTSUPP;
255
256	if (args->version > PTYFS_ARGSVERSION)
257		return EINVAL;
258
259	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
260
261	mp->mnt_data = pmnt;
262	pmnt->pmnt_gid = args->gid;
263	pmnt->pmnt_mode = args->mode;
264	if (args->version >= PTYFS_ARGSVERSION)
265		pmnt->pmnt_flags = args->flags;
266	else
267		pmnt->pmnt_flags = 0;
268	mp->mnt_flag |= MNT_LOCAL;
269	vfs_getnewfsid(mp);
270
271	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
272	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
273		free(pmnt, M_PTYFSMNT);
274		return error;
275	}
276
277	/* Point pty access to us */
278	if (ptyfs_count == 0) {
279		ptm_ptyfspty.arg = mp;
280		ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
281	}
282	ptyfs_count++;
283	return 0;
284}
285
286/*ARGSUSED*/
287int
288ptyfs_start(struct mount *mp, int flags)
289{
290	return 0;
291}
292
293/*ARGSUSED*/
294int
295ptyfs_unmount(struct mount *mp, int mntflags)
296{
297	int error;
298	int flags = 0;
299
300	if (mntflags & MNT_FORCE)
301		flags |= FORCECLOSE;
302
303	if ((error = vflush(mp, 0, flags)) != 0)
304		return error;
305
306	ptyfs_count--;
307	if (ptyfs_count == 0) {
308		/* Restore where pty access was pointing */
309		(void)pty_sethandler(ptyfs_save_ptm);
310		ptyfs_save_ptm = NULL;
311		ptm_ptyfspty.arg = NULL;
312	}
313
314	/*
315	 * Finally, throw away the ptyfsmount structure
316	 */
317	free(mp->mnt_data, M_PTYFSMNT);
318	mp->mnt_data = NULL;
319
320	return 0;
321}
322
323int
324ptyfs_root(struct mount *mp, struct vnode **vpp)
325{
326	/* setup "." */
327	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
328}
329
330/*ARGSUSED*/
331int
332ptyfs_sync(struct mount *mp, int waitfor,
333    kauth_cred_t uc)
334{
335	return 0;
336}
337
338/*
339 * Kernfs flat namespace lookup.
340 * Currently unsupported.
341 */
342/*ARGSUSED*/
343int
344ptyfs_vget(struct mount *mp, ino_t ino,
345    struct vnode **vpp)
346{
347	return EOPNOTSUPP;
348}
349
350extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
351
352const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
353	&ptyfs_vnodeop_opv_desc,
354	NULL,
355};
356
357struct vfsops ptyfs_vfsops = {
358	.vfs_name = MOUNT_PTYFS,
359	.vfs_min_mount_data = sizeof (struct ptyfs_args),
360	.vfs_mount = ptyfs_mount,
361	.vfs_start = ptyfs_start,
362	.vfs_unmount = ptyfs_unmount,
363	.vfs_root = ptyfs_root,
364	.vfs_quotactl = (void *)eopnotsupp,
365	.vfs_statvfs = genfs_statvfs,
366	.vfs_sync = ptyfs_sync,
367	.vfs_vget = ptyfs_vget,
368	.vfs_fhtovp = (void *)eopnotsupp,
369	.vfs_vptofh = (void *)eopnotsupp,
370	.vfs_init = ptyfs_init,
371	.vfs_reinit = ptyfs_reinit,
372	.vfs_done = ptyfs_done,
373	.vfs_snapshot = (void *)eopnotsupp,
374	.vfs_extattrctl = (void *)eopnotsupp,
375	.vfs_suspendctl = (void *)eopnotsupp,
376	.vfs_renamelock_enter = genfs_renamelock_enter,
377	.vfs_renamelock_exit = genfs_renamelock_exit,
378	.vfs_fsync = (void *)eopnotsupp,
379	.vfs_opv_descs = ptyfs_vnodeopv_descs
380};
381
382static int
383ptyfs_modcmd(modcmd_t cmd, void *arg)
384{
385	int error;
386
387	switch (cmd) {
388	case MODULE_CMD_INIT:
389		error = vfs_attach(&ptyfs_vfsops);
390		if (error != 0)
391			break;
392		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
393			       CTLFLAG_PERMANENT,
394			       CTLTYPE_NODE, "ptyfs",
395			       SYSCTL_DESCR("Pty file system"),
396			       NULL, 0, NULL, 0,
397			       CTL_VFS, 23, CTL_EOL);
398		/*
399		 * XXX the "23" above could be dynamic, thereby eliminating
400		 * one more instance of the "number to vfs" mapping problem,
401		 * but "23" is the order as taken from sys/mount.h
402		 */
403		break;
404	case MODULE_CMD_FINI:
405		error = vfs_detach(&ptyfs_vfsops);
406		if (error != 0)
407			break;
408		sysctl_teardown(&ptyfs_sysctl_log);
409		break;
410	default:
411		error = ENOTTY;
412		break;
413	}
414
415	return (error);
416}
417