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1f51470d04
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 commit6e1db57b2a
. Conflicts: console.c hw/baum.c qemu-char.c This reverts commitaad04cd024
. The parts of commitdb418a0a
"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>
79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
/*
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* QEMU Microsoft serial mouse emulation
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*
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* Copyright (c) 2008 Lubomir Rintel
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include "../qemu-common.h"
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#include "../qemu-char.h"
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#include "../console.h"
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#include "msmouse.h"
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#define MSMOUSE_LO6(n) ((n) & 0x3f)
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#define MSMOUSE_HI2(n) (((n) & 0xc0) >> 6)
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static void msmouse_event(void *opaque,
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int dx, int dy, int dz, int buttons_state)
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{
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CharDriverState *chr = (CharDriverState *)opaque;
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unsigned char bytes[4] = { 0x40, 0x00, 0x00, 0x00 };
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/* Movement deltas */
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bytes[0] |= (MSMOUSE_HI2(dy) << 2) | MSMOUSE_HI2(dx);
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bytes[1] |= MSMOUSE_LO6(dx);
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bytes[2] |= MSMOUSE_LO6(dy);
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/* Buttons */
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bytes[0] |= (buttons_state & 0x01 ? 0x20 : 0x00);
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bytes[0] |= (buttons_state & 0x02 ? 0x10 : 0x00);
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bytes[3] |= (buttons_state & 0x04 ? 0x20 : 0x00);
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/* We always send the packet of, so that we do not have to keep track
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of previous state of the middle button. This can potentially confuse
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some very old drivers for two button mice though. */
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qemu_chr_be_write(chr, bytes, 4);
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}
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static int msmouse_chr_write (struct CharDriverState *s, const uint8_t *buf, int len)
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{
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/* Ignore writes to mouse port */
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return len;
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}
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static void msmouse_chr_close (struct CharDriverState *chr)
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{
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g_free (chr);
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}
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CharDriverState *qemu_chr_open_msmouse(QemuOpts *opts)
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{
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CharDriverState *chr;
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chr = g_malloc0(sizeof(CharDriverState));
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chr->chr_write = msmouse_chr_write;
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chr->chr_close = msmouse_chr_close;
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qemu_add_mouse_event_handler(msmouse_event, chr, 0, "QEMU Microsoft Mouse");
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return chr;
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}
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