1/*	$NetBSD: cons.c,v 1.9 2020/01/02 15:42:27 thorpej Exp $	*/
2
3/*
4 * Copyright (c) 2013 Antti Kantee.  All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/*
29 * rumpcons, a (very) simple console-type device which relays output
30 * to the rumpuser_putchar() hypercall.  This is most useful in
31 * environments where there is no Unix-like host (e.g. Xen DomU).
32 * It's currently a truly half duplex console since there is support
33 * only for writing to the console (there is no hypercall for reading
34 * the host console).  The driver attempts to look like a tty just
35 * enough to fool isatty().  Let's see how far that gets us.
36 */
37
38#include <sys/cdefs.h>
39__KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.9 2020/01/02 15:42:27 thorpej Exp $");
40
41#include <sys/param.h>
42#include <sys/file.h>
43#include <sys/filedesc.h>
44#include <sys/ioctl.h>
45#include <sys/kernel.h>
46#include <sys/kmem.h>
47#include <sys/poll.h>
48#include <sys/proc.h>
49#include <sys/stat.h>
50#include <sys/termios.h>
51
52#include <rump-sys/kern.h>
53
54#include <rump/rumpuser.h>
55
56static int rumpcons_write(struct file *, off_t *, struct uio *,
57			  kauth_cred_t, int);
58static int rumpcons_ioctl(struct file *, u_long, void *);
59static int rumpcons_stat(struct file *, struct stat *);
60static int rumpcons_poll(struct file *, int events);
61
62static const struct fileops rumpcons_fileops = {
63	.fo_name = "rumpcons",
64	.fo_read = (void *)nullop,
65	.fo_write = rumpcons_write,
66	.fo_ioctl = rumpcons_ioctl,
67	.fo_fcntl = fnullop_fcntl,
68	.fo_poll = rumpcons_poll,
69	.fo_stat = rumpcons_stat,
70	.fo_close = (void *)nullop,
71	.fo_kqfilter = fnullop_kqfilter,
72	.fo_restart = fnullop_restart,
73};
74
75void
76rump_consdev_init(void)
77{
78	struct file *fp;
79	int fd, error;
80
81	KASSERT(fd_getfile(0) == NULL);
82	KASSERT(fd_getfile(1) == NULL);
83	KASSERT(fd_getfile(2) == NULL);
84
85	/* then, map a file descriptor to the device */
86	if ((error = fd_allocfile(&fp, &fd)) != 0)
87		panic("cons fd_allocfile failed: %d", error);
88
89	fp->f_flag = FWRITE;
90	fp->f_type = DTYPE_MISC;
91	fp->f_ops = &rumpcons_fileops;
92	fp->f_data = NULL;
93	fd_affix(curproc, fp, fd);
94
95	KASSERT(fd == 0);
96	error += fd_dup2(fp, 1, 0);
97	error += fd_dup2(fp, 2, 0);
98
99	if (error)
100		panic("failed to dup fd 0/1/2");
101}
102
103static int
104rumpcons_write(struct file *fp, off_t *off, struct uio *uio,
105	kauth_cred_t cred, int flags)
106{
107	char *buf;
108	size_t len, n;
109	int error = 0;
110
111	buf = kmem_alloc(PAGE_SIZE, KM_SLEEP);
112	while (uio->uio_resid > 0) {
113		len = uimin(PAGE_SIZE, uio->uio_resid);
114		error = uiomove(buf, len, uio);
115		if (error)
116			break;
117
118		for (n = 0; n < len; n++) {
119			rumpuser_putchar(*(buf+n));
120		}
121	}
122	kmem_free(buf, PAGE_SIZE);
123
124	return error;
125}
126
127static int
128rumpcons_ioctl(struct file *fp, u_long cmd, void *data)
129{
130
131	if (cmd == TIOCGETA)
132		return 0;
133
134	return ENOTTY; /* considering how we are cheating, lol */
135}
136
137static int
138rumpcons_stat(struct file *fp, struct stat *sb)
139{
140	struct timespec ts;
141
142	getnanoboottime(&ts);
143
144	memset(sb, 0, sizeof(*sb));
145	sb->st_mode = 0600 | _S_IFCHR;
146	sb->st_atimespec = sb->st_mtimespec = sb->st_ctimespec = ts;
147	sb->st_birthtimespec = ts;
148
149	return 0;
150}
151
152static int
153rumpcons_poll(struct file *fp, int events)
154{
155	int revents = 0;
156
157	if (events & (POLLOUT | POLLWRNORM))
158		revents |= events & (POLLOUT | POLLWRNORM);
159
160	return revents;
161}
162