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>
81 lines
2.4 KiB
C
81 lines
2.4 KiB
C
/*
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* Copyright (C) 2010 Red Hat, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 or
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* (at your option) version 3 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef QEMU_SPICE_H
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#define QEMU_SPICE_H
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#ifdef CONFIG_SPICE
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#include <spice.h>
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#include "qemu-option.h"
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#include "qemu-config.h"
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#include "qemu-char.h"
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#include "monitor.h"
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extern int using_spice;
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void qemu_spice_init(void);
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void qemu_spice_input_init(void);
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void qemu_spice_audio_init(void);
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void qemu_spice_display_init(DisplayState *ds);
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int qemu_spice_display_add_client(int csock, int skipauth, int tls);
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int qemu_spice_add_interface(SpiceBaseInstance *sin);
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int qemu_spice_set_passwd(const char *passwd,
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bool fail_if_connected, bool disconnect_if_connected);
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int qemu_spice_set_pw_expire(time_t expires);
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int qemu_spice_migrate_info(const char *hostname, int port, int tls_port,
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const char *subject,
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MonitorCompletion cb, void *opaque);
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void do_info_spice_print(Monitor *mon, const QObject *data);
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void do_info_spice(Monitor *mon, QObject **ret_data);
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CharDriverState *qemu_chr_open_spice(QemuOpts *opts);
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#else /* CONFIG_SPICE */
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#include "monitor.h"
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#define using_spice 0
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static inline int qemu_spice_set_passwd(const char *passwd,
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bool fail_if_connected,
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bool disconnect_if_connected)
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{
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return -1;
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}
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static inline int qemu_spice_set_pw_expire(time_t expires)
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{
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return -1;
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}
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static inline int qemu_spice_migrate_info(const char *h, int p, int t,
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const char *s,
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MonitorCompletion cb, void *opaque)
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{
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cb(opaque, NULL);
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return -1;
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}
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static inline int qemu_spice_display_add_client(int csock, int skipauth,
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int tls)
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{
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return -1;
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}
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#endif /* CONFIG_SPICE */
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#endif /* QEMU_SPICE_H */
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