ptyfs_vfsops.c revision 1.42 
1/*	$NetBSD: ptyfs_vfsops.c,v 1.42 2010/01/08 11:35:09 pooka 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 1.42 2010/01/08 11:35:09 pooka 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 ptm_pty *, struct lwp *, struct vnode **,
76    dev_t, char);
77static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
78    dev_t, char);
79static void ptyfs__getvattr(struct ptm_pty *, 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	struct ptyfsmount *pmnt = mp->mnt_data;
105
106	rv = mp->mnt_stat.f_mntonname;
107	if (cwdi->cwdi_rdir == NULL ||
108	    (pmnt->pmnt_flags & PTYFSMNT_CHROOT) == 0)
109		return rv;
110
111	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
112	bp = buf + MAXBUF;
113	*--bp = '\0';
114	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
115	    buf, MAXBUF / 2, 0, l);
116	if (error)	/* XXX */
117		goto out;
118
119	len = strlen(bp);
120	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
121		rv += len;
122out:
123	free(buf, M_TEMP);
124	return rv;
125}
126
127static int
128ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
129    dev_t dev, char ms)
130{
131	struct mount *mp = pt->arg;
132	size_t len;
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		len = snprintf(tbuf, bufsiz, "%s/%llu", ptyfs__getpath(l, mp),
141		    (unsigned long long)minor(dev));
142		break;
143	default:
144		return EINVAL;
145	}
146
147	return len >= bufsiz ? ENOSPC : 0;
148}
149
150
151static int
152/*ARGSUSED*/
153ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
154    dev_t dev, char ms)
155{
156	struct mount *mp = pt->arg;
157	ptyfstype type;
158
159	switch (ms) {
160	case 'p':
161		type = PTYFSptc;
162		break;
163	case 't':
164		type = PTYFSpts;
165		break;
166	default:
167		return EINVAL;
168	}
169
170	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
171}
172
173
174static void
175ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
176{
177	struct mount *mp = pt->arg;
178	struct ptyfsmount *pmnt = VFSTOPTY(mp);
179	vattr_null(vattr);
180	/* get real uid */
181	vattr->va_uid = kauth_cred_getuid(l->l_cred);
182	vattr->va_gid = pmnt->pmnt_gid;
183	vattr->va_mode = pmnt->pmnt_mode;
184}
185
186
187void
188ptyfs_init(void)
189{
190
191	malloc_type_attach(M_PTYFSMNT);
192	malloc_type_attach(M_PTYFSTMP);
193	ptyfs_hashinit();
194}
195
196void
197ptyfs_reinit(void)
198{
199	ptyfs_hashreinit();
200}
201
202void
203ptyfs_done(void)
204{
205
206	ptyfs_hashdone();
207	malloc_type_detach(M_PTYFSTMP);
208	malloc_type_detach(M_PTYFSMNT);
209}
210
211#define OSIZE sizeof(struct { int f; gid_t g; mode_t m; })
212/*
213 * Mount the Pseudo tty params filesystem
214 */
215int
216ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
217{
218	struct lwp *l = curlwp;
219	int error = 0;
220	struct ptyfsmount *pmnt;
221	struct ptyfs_args *args = data;
222
223	if (*data_len != sizeof *args && *data_len != OSIZE)
224		return EINVAL;
225
226	if (UIO_MX & (UIO_MX - 1)) {
227		log(LOG_ERR, "ptyfs: invalid directory entry size");
228		return EINVAL;
229	}
230
231	if (mp->mnt_flag & MNT_GETARGS) {
232		pmnt = VFSTOPTY(mp);
233		if (pmnt == NULL)
234			return EIO;
235		args->mode = pmnt->pmnt_mode;
236		args->gid = pmnt->pmnt_gid;
237		if (args->version >= PTYFS_ARGSVERSION) {
238			args->flags = pmnt->pmnt_flags;
239			*data_len = sizeof *args;
240		} else {
241			*data_len = OSIZE;
242		}
243		return 0;
244	}
245
246	/* Don't allow more than one mount */
247	if (ptyfs_count)
248		return EBUSY;
249
250	if (mp->mnt_flag & MNT_UPDATE)
251		return EOPNOTSUPP;
252
253	if (args->version > PTYFS_ARGSVERSION)
254		return EINVAL;
255
256	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
257
258	mp->mnt_data = pmnt;
259	pmnt->pmnt_gid = args->gid;
260	pmnt->pmnt_mode = args->mode;
261	if (args->version >= PTYFS_ARGSVERSION)
262		pmnt->pmnt_flags = args->flags;
263	else
264		pmnt->pmnt_flags = 0;
265	mp->mnt_flag |= MNT_LOCAL;
266	vfs_getnewfsid(mp);
267
268	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
269	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
270		free(pmnt, M_PTYFSMNT);
271		return error;
272	}
273
274	/* Point pty access to us */
275
276	ptm_ptyfspty.arg = mp;
277	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
278	ptyfs_count++;
279	return 0;
280}
281
282/*ARGSUSED*/
283int
284ptyfs_start(struct mount *mp, int flags)
285{
286	return 0;
287}
288
289/*ARGSUSED*/
290int
291ptyfs_unmount(struct mount *mp, int mntflags)
292{
293	int error;
294	int flags = 0;
295
296	if (mntflags & MNT_FORCE)
297		flags |= FORCECLOSE;
298
299	if ((error = vflush(mp, 0, flags)) != 0)
300		return (error);
301
302	/* Restore where pty access was pointing */
303	(void)pty_sethandler(ptyfs_save_ptm);
304	ptyfs_save_ptm = NULL;
305	ptm_ptyfspty.arg = NULL;
306
307	/*
308	 * Finally, throw away the ptyfsmount structure
309	 */
310	free(mp->mnt_data, M_PTYFSMNT);
311	mp->mnt_data = NULL;
312	ptyfs_count--;
313
314	return 0;
315}
316
317int
318ptyfs_root(struct mount *mp, struct vnode **vpp)
319{
320	/* setup "." */
321	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
322}
323
324/*ARGSUSED*/
325int
326ptyfs_sync(struct mount *mp, int waitfor,
327    kauth_cred_t uc)
328{
329	return 0;
330}
331
332/*
333 * Kernfs flat namespace lookup.
334 * Currently unsupported.
335 */
336/*ARGSUSED*/
337int
338ptyfs_vget(struct mount *mp, ino_t ino,
339    struct vnode **vpp)
340{
341	return EOPNOTSUPP;
342}
343
344extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
345
346const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
347	&ptyfs_vnodeop_opv_desc,
348	NULL,
349};
350
351struct vfsops ptyfs_vfsops = {
352	MOUNT_PTYFS,
353	sizeof (struct ptyfs_args),
354	ptyfs_mount,
355	ptyfs_start,
356	ptyfs_unmount,
357	ptyfs_root,
358	(void *)eopnotsupp,		/* vfs_quotactl */
359	genfs_statvfs,
360	ptyfs_sync,
361	ptyfs_vget,
362	(void *)eopnotsupp,		/* vfs_fhtovp */
363	(void *)eopnotsupp,		/* vfs_vptofp */
364	ptyfs_init,
365	ptyfs_reinit,
366	ptyfs_done,
367	NULL,				/* vfs_mountroot */
368	(void *)eopnotsupp,
369	(void *)eopnotsupp,
370	(void *)eopnotsupp,		/* vfs_suspendctl */
371	genfs_renamelock_enter,
372	genfs_renamelock_exit,
373	(void *)eopnotsupp,
374	ptyfs_vnodeopv_descs,
375	0,
376	{ NULL, NULL },
377};
378
379static int
380ptyfs_modcmd(modcmd_t cmd, void *arg)
381{
382	int error;
383
384	switch (cmd) {
385	case MODULE_CMD_INIT:
386		error = vfs_attach(&ptyfs_vfsops);
387		if (error != 0)
388			break;
389		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
390			       CTLFLAG_PERMANENT,
391			       CTLTYPE_NODE, "vfs", NULL,
392			       NULL, 0, NULL, 0,
393			       CTL_VFS, CTL_EOL);
394		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
395			       CTLFLAG_PERMANENT,
396			       CTLTYPE_NODE, "ptyfs",
397			       SYSCTL_DESCR("Pty file system"),
398			       NULL, 0, NULL, 0,
399			       CTL_VFS, 23, CTL_EOL);
400		/*
401		 * XXX the "23" above could be dynamic, thereby eliminating
402		 * one more instance of the "number to vfs" mapping problem,
403		 * but "23" is the order as taken from sys/mount.h
404		 */
405		break;
406	case MODULE_CMD_FINI:
407		error = vfs_detach(&ptyfs_vfsops);
408		if (error != 0)
409			break;
410		sysctl_teardown(&ptyfs_sysctl_log);
411		break;
412	default:
413		error = ENOTTY;
414		break;
415	}
416
417	return (error);
418}
419