ptyfs_vfsops.c revision 1.36 
1/*	$NetBSD: ptyfs_vfsops.c,v 1.36 2008/06/28 01:34:05 rumble 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 1.36 2008/06/28 01:34:05 rumble 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
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(cwdi->cwdi_rdir, rootvnode, &bp,
113	    buf, MAXBUF / 2, 0, l);
114	if (error)	/* XXX */
115		goto out;
116
117	len = strlen(bp);
118	if (len < sizeof(mp->mnt_stat.f_mntonname))	/* XXX */
119		rv += len;
120out:
121	free(buf, M_TEMP);
122	return rv;
123}
124
125static int
126ptyfs__makename(struct ptm_pty *pt, struct lwp *l, char *tbuf, size_t bufsiz,
127    dev_t dev, char ms)
128{
129	struct mount *mp = pt->arg;
130	size_t len;
131
132	switch (ms) {
133	case 'p':
134		/* We don't provide access to the master, should we? */
135		len = snprintf(tbuf, bufsiz, "/dev/null");
136		break;
137	case 't':
138		len = snprintf(tbuf, bufsiz, "%s/%d", ptyfs__getpath(l, mp),
139		    minor(dev));
140		break;
141	default:
142		return EINVAL;
143	}
144
145	return len >= bufsiz ? ENOSPC : 0;
146}
147
148
149static int
150/*ARGSUSED*/
151ptyfs__allocvp(struct ptm_pty *pt, struct lwp *l, struct vnode **vpp,
152    dev_t dev, char ms)
153{
154	struct mount *mp = pt->arg;
155	ptyfstype type;
156
157	switch (ms) {
158	case 'p':
159		type = PTYFSptc;
160		break;
161	case 't':
162		type = PTYFSpts;
163		break;
164	default:
165		return EINVAL;
166	}
167
168	return ptyfs_allocvp(mp, vpp, type, minor(dev), l);
169}
170
171
172static void
173ptyfs__getvattr(struct ptm_pty *pt, struct lwp *l, struct vattr *vattr)
174{
175	struct mount *mp = pt->arg;
176	struct ptyfsmount *pmnt = VFSTOPTY(mp);
177	VATTR_NULL(vattr);
178	/* get real uid */
179	vattr->va_uid = kauth_cred_getuid(l->l_cred);
180	vattr->va_gid = pmnt->pmnt_gid;
181	vattr->va_mode = pmnt->pmnt_mode;
182}
183
184
185void
186ptyfs_init(void)
187{
188
189	malloc_type_attach(M_PTYFSMNT);
190	malloc_type_attach(M_PTYFSTMP);
191	ptyfs_hashinit();
192}
193
194void
195ptyfs_reinit(void)
196{
197	ptyfs_hashreinit();
198}
199
200void
201ptyfs_done(void)
202{
203
204	ptyfs_hashdone();
205	malloc_type_detach(M_PTYFSTMP);
206	malloc_type_detach(M_PTYFSMNT);
207}
208
209/*
210 * Mount the Pseudo tty params filesystem
211 */
212int
213ptyfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
214{
215	struct lwp *l = curlwp;
216	int error = 0;
217	struct ptyfsmount *pmnt;
218	struct ptyfs_args *args = data;
219
220	if (*data_len < sizeof *args)
221		return EINVAL;
222
223	if (UIO_MX & (UIO_MX - 1)) {
224		log(LOG_ERR, "ptyfs: invalid directory entry size");
225		return EINVAL;
226	}
227
228	if (mp->mnt_flag & MNT_GETARGS) {
229		pmnt = VFSTOPTY(mp);
230		if (pmnt == NULL)
231			return EIO;
232		args->version = PTYFS_ARGSVERSION;
233		args->mode = pmnt->pmnt_mode;
234		args->gid = pmnt->pmnt_gid;
235		*data_len = sizeof *args;
236		return 0;
237	}
238
239	/* Don't allow more than one mount */
240	if (ptyfs_count)
241		return EBUSY;
242
243	if (mp->mnt_flag & MNT_UPDATE)
244		return EOPNOTSUPP;
245
246	if (args->version != PTYFS_ARGSVERSION)
247		return EINVAL;
248
249	pmnt = malloc(sizeof(struct ptyfsmount), M_PTYFSMNT, M_WAITOK);
250
251	mp->mnt_data = pmnt;
252	pmnt->pmnt_gid = args->gid;
253	pmnt->pmnt_mode = args->mode;
254	mp->mnt_flag |= MNT_LOCAL;
255	vfs_getnewfsid(mp);
256
257	if ((error = set_statvfs_info(path, UIO_USERSPACE, "ptyfs",
258	    UIO_SYSSPACE, mp->mnt_op->vfs_name, mp, l)) != 0) {
259		free(pmnt, M_PTYFSMNT);
260		return error;
261	}
262
263	/* Point pty access to us */
264
265	ptm_ptyfspty.arg = mp;
266	ptyfs_save_ptm = pty_sethandler(&ptm_ptyfspty);
267	ptyfs_count++;
268	return 0;
269}
270
271/*ARGSUSED*/
272int
273ptyfs_start(struct mount *mp, int flags)
274{
275	return 0;
276}
277
278/*ARGSUSED*/
279int
280ptyfs_unmount(struct mount *mp, int mntflags)
281{
282	int error;
283	int flags = 0;
284
285	if (mntflags & MNT_FORCE)
286		flags |= FORCECLOSE;
287
288	if ((error = vflush(mp, 0, flags)) != 0)
289		return (error);
290
291	/* Restore where pty access was pointing */
292	(void)pty_sethandler(ptyfs_save_ptm);
293	ptyfs_save_ptm = NULL;
294	ptm_ptyfspty.arg = NULL;
295
296	/*
297	 * Finally, throw away the ptyfsmount structure
298	 */
299	free(mp->mnt_data, M_PTYFSMNT);
300	mp->mnt_data = NULL;
301	ptyfs_count--;
302
303	return 0;
304}
305
306int
307ptyfs_root(struct mount *mp, struct vnode **vpp)
308{
309	/* setup "." */
310	return ptyfs_allocvp(mp, vpp, PTYFSroot, 0, NULL);
311}
312
313/*ARGSUSED*/
314int
315ptyfs_statvfs(struct mount *mp, struct statvfs *sbp)
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)
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
353extern const struct vnodeopv_desc ptyfs_vnodeop_opv_desc;
354
355const struct vnodeopv_desc * const ptyfs_vnodeopv_descs[] = {
356	&ptyfs_vnodeop_opv_desc,
357	NULL,
358};
359
360struct vfsops ptyfs_vfsops = {
361	MOUNT_PTYFS,
362	sizeof (struct ptyfs_args),
363	ptyfs_mount,
364	ptyfs_start,
365	ptyfs_unmount,
366	ptyfs_root,
367	(void *)eopnotsupp,		/* vfs_quotactl */
368	ptyfs_statvfs,
369	ptyfs_sync,
370	ptyfs_vget,
371	(void *)eopnotsupp,		/* vfs_fhtovp */
372	(void *)eopnotsupp,		/* vfs_vptofp */
373	ptyfs_init,
374	ptyfs_reinit,
375	ptyfs_done,
376	NULL,				/* vfs_mountroot */
377	(void *)eopnotsupp,
378	(void *)eopnotsupp,
379	(void *)eopnotsupp,		/* vfs_suspendctl */
380	genfs_renamelock_enter,
381	genfs_renamelock_exit,
382	(void *)eopnotsupp,
383	ptyfs_vnodeopv_descs,
384	0,
385	{ NULL, NULL },
386};
387
388static int
389ptyfs_modcmd(modcmd_t cmd, void *arg)
390{
391	int error;
392
393	switch (cmd) {
394	case MODULE_CMD_INIT:
395		error = vfs_attach(&ptyfs_vfsops);
396		if (error != 0)
397			break;
398		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
399			       CTLFLAG_PERMANENT,
400			       CTLTYPE_NODE, "vfs", NULL,
401			       NULL, 0, NULL, 0,
402			       CTL_VFS, CTL_EOL);
403		sysctl_createv(&ptyfs_sysctl_log, 0, NULL, NULL,
404			       CTLFLAG_PERMANENT,
405			       CTLTYPE_NODE, "ptyfs",
406			       SYSCTL_DESCR("Pty file system"),
407			       NULL, 0, NULL, 0,
408			       CTL_VFS, 23, CTL_EOL);
409		/*
410		 * XXX the "23" above could be dynamic, thereby eliminating
411		 * one more instance of the "number to vfs" mapping problem,
412		 * but "23" is the order as taken from sys/mount.h
413		 */
414		break;
415	case MODULE_CMD_FINI:
416		error = vfs_detach(&ptyfs_vfsops);
417		if (error != 0)
418			break;
419		sysctl_teardown(&ptyfs_sysctl_log);
420		break;
421	default:
422		error = ENOTTY;
423		break;
424	}
425
426	return (error);
427}
428