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cons.c revision 1.4 
      1 /*	$NetBSD: cons.c,v 1.4 2014/08/25 14:58:48 pooka 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 1.4 2014/08/25 14:58:48 pooka 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/proc.h>
     48 #include <sys/stat.h>
     49 #include <sys/termios.h>
     50 
     51 #include <rump/rumpuser.h>
     52 
     53 #include "rump_private.h"
     54 
     55 static int rumpcons_write(struct file *, off_t *, struct uio *,
     56 			  kauth_cred_t, int);
     57 static int rumpcons_ioctl(struct file *, u_long, void *);
     58 static int rumpcons_stat(struct file *, struct stat *);
     59 
     60 static const struct fileops rumpcons_fileops = {
     61 	.fo_read = (void *)nullop,
     62 	.fo_write = rumpcons_write,
     63 	.fo_ioctl = rumpcons_ioctl,
     64 	.fo_fcntl = fnullop_fcntl,
     65 	.fo_poll = fnullop_poll,
     66 	.fo_stat = rumpcons_stat,
     67 	.fo_close = (void *)nullop,
     68 	.fo_kqfilter = fnullop_kqfilter,
     69 	.fo_restart = fnullop_restart,
     70 };
     71 
     72 void
     73 rump_consdev_init(void)
     74 {
     75 	struct file *fp;
     76 	int fd, error;
     77 
     78 	KASSERT(fd_getfile(0) == NULL);
     79 	KASSERT(fd_getfile(1) == NULL);
     80 	KASSERT(fd_getfile(2) == NULL);
     81 
     82 	/* then, map a file descriptor to the device */
     83 	if ((error = fd_allocfile(&fp, &fd)) != 0)
     84 		panic("cons fd_allocfile failed: %d", error);
     85 
     86 	fp->f_flag = FWRITE;
     87 	fp->f_type = DTYPE_MISC;
     88 	fp->f_ops = &rumpcons_fileops;
     89 	fp->f_data = NULL;
     90 	fd_affix(curproc, fp, fd);
     91 
     92 	KASSERT(fd == 0);
     93 	error += fd_dup2(fp, 1, 0);
     94 	error += fd_dup2(fp, 2, 0);
     95 
     96 	if (error)
     97 		panic("failed to dup fd 0/1/2");
     98 }
     99 
    100 static int
    101 rumpcons_write(struct file *fp, off_t *off, struct uio *uio,
    102 	kauth_cred_t cred, int flags)
    103 {
    104 	char *buf;
    105 	size_t len, n;
    106 	int error = 0;
    107 
    108 	buf = kmem_alloc(PAGE_SIZE, KM_SLEEP);
    109 	while (uio->uio_resid > 0) {
    110 		len = min(PAGE_SIZE, uio->uio_resid);
    111 		error = uiomove(buf, len, uio);
    112 		if (error)
    113 			break;
    114 
    115 		for (n = 0; n < len; n++) {
    116 			rumpuser_putchar(*(buf+n));
    117 		}
    118 	}
    119 	kmem_free(buf, PAGE_SIZE);
    120 
    121 	return error;
    122 }
    123 
    124 static int
    125 rumpcons_ioctl(struct file *fp, u_long cmd, void *data)
    126 {
    127 
    128 	if (cmd == TIOCGETA)
    129 		return 0;
    130 
    131 	return ENOTTY; /* considering how we are cheating, lol */
    132 }
    133 
    134 static int
    135 rumpcons_stat(struct file *fp, struct stat *sb)
    136 {
    137 
    138 	memset(sb, 0, sizeof(*sb));
    139 	sb->st_mode = 0600 | _S_IFCHR;
    140 	sb->st_atimespec = sb->st_mtimespec = sb->st_ctimespec = boottime;
    141 	sb->st_birthtimespec = boottime;
    142 
    143 	return 0;
    144 }
    145