ptyfs_vfsops.c revision 1.28 
1/*	$NetBSD: ptyfs_vfsops.c,v 1.28 2007/07/31 21:14:18 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 1.28 2007/07/31 21:14:18 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
61#include <fs/ptyfs/ptyfs.h>
62#include <miscfs/specfs/specdev.h>
63
64MALLOC_JUSTDEFINE(M_PTYFSMNT, "ptyfs mount", "ptyfs mount structures");
65
66VFS_PROTOS(ptyfs);
67
68static int ptyfs__allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
69    dev_t, char);
70static int ptyfs__makename(struct ptm_pty *, struct lwp *, char *, size_t,
71    dev_t, char);
72static void ptyfs__getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
73
74/*
75 * ptm glue: When we mount, we make ptm point to us.
76 */
77struct ptm_pty *ptyfs_save_ptm;
78static int ptyfs_count;
79
80struct ptm_pty ptm_ptyfspty = {
81	ptyfs__allocvp,
82	ptyfs__makename,
83	ptyfs__getvattr,
84	NULL
85};
86
87static const char *
88ptyfs__getpath(struct lwp *l, const struct mount *mp)
89{
90#define MAXBUF (sizeof(mp->mnt_stat.f_mntonname) + 32)
91	struct cwdinfo *cwdi = l->l_proc->p_cwdi;
92	char *buf;
93	const char *rv;
94	size_t len;
95	char *bp;
96	int error;
97
98	rv = mp->mnt_stat.f_mntonname;
99	if (cwdi->cwdi_rdir == NULL)
100		return rv;
101
102	buf = malloc(MAXBUF, M_TEMP, M_WAITOK);
103	bp = buf + MAXBUF;
104	*--bp = '\0';
105	error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
106	    buf, MAXBUF / 2, 0, l);
107	if (error)	/* XXX */
108		goto out;
109
110	len = strlen(bp);
111	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
112		rv += len;
113out:
114	free(buf, M_TEMP);
115	return rv;
116}
117
118static int
119ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
120    dev_t dev, char ms)
121{
122	struct mount *mp = pt->arg;
123	size_t len;
124
125	switch (ms) {
126	case 'p':
127		/* We don't provide access to the master, should we? */
128		len = snprintf(tbuf, bufsiz, "/dev/null");
129		break;
130	case 't':
131		len = snprintf(tbuf, bufsiz, "%s/%d", ptyfs__getpath(l, mp),
132		    minor(dev));
133		break;
134	default:
135		return EINVAL;
136	}
137
138	return len >= bufsiz ? ENOSPC : 0;
139}
140
141
142static int
143/*ARGSUSED*/
144ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
145    dev_t dev, char ms)
146{
147	struct mount *mp = pt->arg;
148	ptyfstype type;
149
150	switch (ms) {
151	case 'p':
152		type = PTYFSptc;
153		break;
154	case 't':
155		type = PTYFSpts;
156		break;
157	default:
158		return EINVAL;
159	}
160
161	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
162}
163
164
165static void
166ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
167{
168	struct mount *mp = pt->arg;
169	struct ptyfsmount *pmnt = VFSTOPTY(mp);
170	VATTR_NULL(vattr);
171	/* get real uid */
172	vattr->va_uid = kauth_cred_getuid(l->l_cred);
173	vattr->va_gid = pmnt->pmnt_gid;
174	vattr->va_mode = pmnt->pmnt_mode;
175}
176
177
178void
179ptyfs_init(void)
180{
181
182	malloc_type_attach(M_PTYFSMNT);
183	ptyfs_hashinit();
184}
185
186void
187ptyfs_reinit(void)
188{
189	ptyfs_hashreinit();
190}
191
192void
193ptyfs_done(void)
194{
195
196	ptyfs_hashdone();
197	malloc_type_detach(M_PTYFSMNT);
198}
199
200/*
201 * Mount the Pseudo tty params filesystem
202 */
203int
204ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len,
205    struct lwp *l)
206{
207	int error = 0;
208	struct ptyfsmount *pmnt;
209	struct ptyfs_args *args = data;
210
211	if (*data_len < sizeof *args)
212		return EINVAL;
213
214	if (UIO_MX & (UIO_MX - 1)) {
215		log(LOG_ERR, "ptyfs: invalid directory entry size");
216		return EINVAL;
217	}
218
219	if (mp->mnt_flag & MNT_GETARGS) {
220		pmnt = VFSTOPTY(mp);
221		if (pmnt == NULL)
222			return EIO;
223		args->version = PTYFS_ARGSVERSION;
224		args->mode = pmnt->pmnt_mode;
225		args->gid = pmnt->pmnt_gid;
226		*data_len = sizeof *args;
227		return 0;
228	}
229
230	/* Don't allow more than one mount */
231	if (ptyfs_count)
232		return EBUSY;
233
234	if (mp->mnt_flag & MNT_UPDATE)
235		return EOPNOTSUPP;
236
237	if (args->version != PTYFS_ARGSVERSION)
238		return EINVAL;
239
240	pmnt = malloc(sizeof(struct ptyfsmount), M_UFSMNT, M_WAITOK);
241
242	mp->mnt_data = pmnt;
243	pmnt->pmnt_gid = args->gid;
244	pmnt->pmnt_mode = args->mode;
245	mp->mnt_flag |= MNT_LOCAL;
246	vfs_getnewfsid(mp);
247
248	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
249	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
250		free(pmnt, M_UFSMNT);
251		return error;
252	}
253
254	/* Point pty access to us */
255
256	ptm_ptyfspty.arg = mp;
257	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
258	ptyfs_count++;
259	return 0;
260}
261
262/*ARGSUSED*/
263int
264ptyfs_start(struct mount *mp, int flags,
265    struct lwp *p)
266{
267	return 0;
268}
269
270/*ARGSUSED*/
271int
272ptyfs_unmount(struct mount *mp, int mntflags, struct lwp *p)
273{
274	int error;
275	int flags = 0;
276
277	if (mntflags & MNT_FORCE)
278		flags |= FORCECLOSE;
279
280	if ((error = vflush(mp, 0, flags)) != 0)
281		return (error);
282
283	/* Restore where pty access was pointing */
284	(void)pty_sethandler(ptyfs_save_ptm);
285	ptyfs_save_ptm = NULL;
286	ptm_ptyfspty.arg = NULL;
287
288	/*
289	 * Finally, throw away the ptyfsmount structure
290	 */
291	free(mp->mnt_data, M_UFSMNT);
292	mp->mnt_data = 0;
293	ptyfs_count--;
294
295	return 0;
296}
297
298int
299ptyfs_root(struct mount *mp, struct vnode **vpp)
300{
301	/* setup "." */
302	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
303}
304
305/*ARGSUSED*/
306int
307ptyfs_quotactl(struct mount *mp, int cmd, uid_t uid,
308    void *arg, struct lwp *p)
309{
310	return EOPNOTSUPP;
311}
312
313/*ARGSUSED*/
314int
315ptyfs_statvfs(struct mount *mp, struct statvfs *sbp, struct lwp *p)
316{
317	sbp->f_bsize = DEV_BSIZE;
318	sbp->f_frsize = DEV_BSIZE;
319	sbp->f_iosize = DEV_BSIZE;
320	sbp->f_blocks = 2;		/* 1K to keep df happy */
321	sbp->f_bfree = 0;
322	sbp->f_bavail = 0;
323	sbp->f_bresvd = 0;
324	sbp->f_files = 1024;	/* XXX lie */
325	sbp->f_ffree = 128;	/* XXX lie */
326	sbp->f_favail = 128;	/* XXX lie */
327	sbp->f_fresvd = 0;
328	sbp->f_namemax = MAXNAMLEN;
329	copy_statvfs_info(sbp, mp);
330	return 0;
331}
332
333/*ARGSUSED*/
334int
335ptyfs_sync(struct mount *mp, int waitfor,
336    kauth_cred_t uc, struct lwp *p)
337{
338	return 0;
339}
340
341/*
342 * Kernfs flat namespace lookup.
343 * Currently unsupported.
344 */
345/*ARGSUSED*/
346int
347ptyfs_vget(struct mount *mp, ino_t ino,
348    struct vnode **vpp)
349{
350	return EOPNOTSUPP;
351}
352
353SYSCTL_SETUP(sysctl_vfs_ptyfs_setup, "sysctl vfs.ptyfs subtree setup")
354{
355
356	sysctl_createv(clog, 0, NULL, NULL,
357		       CTLFLAG_PERMANENT,
358		       CTLTYPE_NODE, "vfs", NULL,
359		       NULL, 0, NULL, 0,
360		       CTL_VFS, CTL_EOL);
361	sysctl_createv(clog, 0, NULL, NULL,
362		       CTLFLAG_PERMANENT,
363		       CTLTYPE_NODE, "ptyfs",
364		       SYSCTL_DESCR("Pty file system"),
365		       NULL, 0, NULL, 0,
366		       CTL_VFS, 23, CTL_EOL);
367	/*
368	 * XXX the "23" above could be dynamic, thereby eliminating
369	 * one more instance of the "number to vfs" mapping problem,
370	 * but "23" is the order as taken from sys/mount.h
371	 */
372}
373
374
375extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
376
377const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
378	&ptyfs_vnodeop_opv_desc,
379	NULL,
380};
381
382struct vfsops ptyfs_vfsops = {
383	MOUNT_PTYFS,
384	sizeof (struct ptyfs_args),
385	ptyfs_mount,
386	ptyfs_start,
387	ptyfs_unmount,
388	ptyfs_root,
389	ptyfs_quotactl,
390	ptyfs_statvfs,
391	ptyfs_sync,
392	ptyfs_vget,
393	(void *)eopnotsupp,		/* vfs_fhtovp */
394	(void *)eopnotsupp,		/* vfs_vptofp */
395	ptyfs_init,
396	ptyfs_reinit,
397	ptyfs_done,
398	NULL,				/* vfs_mountroot */
399	(int (*)(struct mount *, struct vnode *, struct timespec *))eopnotsupp,
400	(int (*)(struct mount *, int, struct vnode *, int, const char *,
401	    struct lwp *))eopnotsupp,
402	(void *)eopnotsupp,		/* vfs_suspendctl */
403	ptyfs_vnodeopv_descs,
404	0,
405	{ NULL, NULL },
406};
407VFS_ATTACH(ptyfs_vfsops);
408