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      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 
     56 static int rumpcons_write(struct file *, off_t *, struct uio *,
     57 			  kauth_cred_t, int);
     58 static int rumpcons_ioctl(struct file *, u_long, void *);
     59 static int rumpcons_stat(struct file *, struct stat *);
     60 static int rumpcons_poll(struct file *, int events);
     61 
     62 static 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 
     75 void
     76 rump_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 
    103 static int
    104 rumpcons_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 
    127 static int
    128 rumpcons_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 
    137 static int
    138 rumpcons_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 
    152 static int
    153 rumpcons_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