qemu/backends/msmouse.c

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/*
* QEMU Microsoft serial mouse emulation
*
* Copyright (c) 2008 Lubomir Rintel
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdlib.h>
#include "qemu-common.h"
#include "char/char.h"
#include "ui/console.h"
#define MSMOUSE_LO6(n) ((n) & 0x3f)
#define MSMOUSE_HI2(n) (((n) & 0xc0) >> 6)
static void msmouse_event(void *opaque,
int dx, int dy, int dz, int buttons_state)
{
CharDriverState *chr = (CharDriverState *)opaque;
unsigned char bytes[4] = { 0x40, 0x00, 0x00, 0x00 };
/* Movement deltas */
bytes[0] |= (MSMOUSE_HI2(dy) << 2) | MSMOUSE_HI2(dx);
bytes[1] |= MSMOUSE_LO6(dx);
bytes[2] |= MSMOUSE_LO6(dy);
/* Buttons */
bytes[0] |= (buttons_state & 0x01 ? 0x20 : 0x00);
bytes[0] |= (buttons_state & 0x02 ? 0x10 : 0x00);
bytes[3] |= (buttons_state & 0x04 ? 0x20 : 0x00);
/* We always send the packet of, so that we do not have to keep track
of previous state of the middle button. This can potentially confuse
some very old drivers for two button mice though. */
qemu_chr_be_write(chr, bytes, 4);
}
static int msmouse_chr_write (struct CharDriverState *s, const uint8_t *buf, int len)
{
/* Ignore writes to mouse port */
return len;
}
static void msmouse_chr_close (struct CharDriverState *chr)
{
g_free (chr);
}
static CharDriverState *qemu_chr_open_msmouse(QemuOpts *opts)
{
CharDriverState *chr;
chr = g_malloc0(sizeof(CharDriverState));
chr->chr_write = msmouse_chr_write;
chr->chr_close = msmouse_chr_close;
qemu_add_mouse_event_handler(msmouse_event, chr, 0, "QEMU Microsoft Mouse");
Revert "qemu-char: Print strerror message on failure" and deps The commit's purpose is laudable: The only way for chardev drivers to communicate an error was to return a NULL pointer, which resulted in an error message that said _that_ something went wrong, but not _why_. It attempts to achieve it by changing the interface to return 0/-errno and update qemu_chr_open_opts() to use strerror() to display a more helpful error message. Unfortunately, it has serious flaws: 1. Backends "socket" and "udp" return bogus error codes, because qemu_chr_open_socket() and qemu_chr_open_udp() assume that unix_listen_opts(), unix_connect_opts(), inet_listen_opts(), inet_connect_opts() and inet_dgram_opts() fail with errno set appropriately. That assumption is wrong, and the commit turns unspecific error messages into misleading error messages. For instance: $ qemu-system-x86_64 -nodefaults -vnc :0 -chardev socket,id=bar,host=xxx inet_connect: host and/or port not specified chardev: opening backend "socket" failed: No such file or directory ENOENT is what happens to be in my errno when the backend returns -errno. Let's put ERANGE there just for giggles: $ qemu-system-x86_64 -nodefaults -vnc :0 -chardev socket,id=bar,host=xxx -drive if=none,iops=99999999999999999999 inet_connect: host and/or port not specified chardev: opening backend "socket" failed: Numerical result out of range Worse: when errno happens to be zero, return -errno erroneously signals success, and qemu_chr_new_from_opts() dies dereferencing uninitialized chr. I observe this with "-serial unix:". 2. All qemu_chr_open_opts() knows about the error is an errno error code. That's simply not enough for a decent message. For instance, when inet_dgram() can't resolve the parameter host, which errno code should it use? What if it can't resolve parameter localaddr? Clue: many backends already report errors in their open methods. Let's revert the flawed commit along with its dependencies, and fix up the silent error paths instead. This reverts commit 6e1db57b2ac9025c2443c665a0d9e78748637b26. Conflicts: console.c hw/baum.c qemu-char.c This reverts commit aad04cd024f0c59f0b96f032cde2e24eb3abba6d. The parts of commit db418a0a "Add stdio char device on windows" that depend on the reverted change fixed up. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-07 18:09:08 +04:00
return chr;
}
static void register_types(void)
{
register_char_driver("msmouse", qemu_chr_open_msmouse);
}
type_init(register_types);