qemu/include/monitor/monitor.h
Markus Armbruster 65207c59d9 monitor: Drop broken, unused asynchronous command interface
The asynchronous monitor command interface goes back to commit 940cc30
(Jan 2010).  Added a third case to command execution.  The hope back
then according to the commit message was that all commands get
converted to the asynchronous interface, killing off the other two
cases.  Didn't happen.

The initial asynchronous commands balloon and info balloon were
converted back to synchronous long ago (commit 96637bc and d72f32),
with commit messages calling the asynchronous interface "not fully
working" and "deprecated".  The only other user went away in commit
3b5704b.

New code generally uses synchronous commands and asynchronous events.

What exactly is still "not fully working" with asynchronous commands?
Well, here's a bug that defeats actual asynchronous use pretty
reliably: the reply's ID is wrong (and has always been wrong) unless
you use the command synchronously!  To reproduce, we need an
asynchronous command, so we have to go back before commit 3b5704b.
Run QEMU with spice:

    $ qemu-system-x86_64 -nodefaults -S -spice port=5900,disable-ticketing -qmp stdio
    {"QMP": {"version": {"qemu": {"micro": 94, "minor": 2, "major": 2}, "package": ""}, "capabilities": []}}

Connect a spice client in another terminal:

    $ remote-viewer spice://localhost:5900

Set up a migration destination dummy in a third terminal:

    $ socat TCP-LISTEN:12345 STDIO

Now paste the following into the QMP monitor:

    { "execute": "qmp_capabilities", "id": "i0" }
    { "execute": "client_migrate_info", "id": "i1", "arguments": { "protocol": "spice", "hostname": "localhost", "port": 12345 } }
    { "execute": "query-kvm", "id": "i2" }

Produces two replies immediately, one to qmp_capabilities, and one to
query-kvm:

    {"return": {}, "id": "i0"}
    {"return": {"enabled": false, "present": true}, "id": "i2"}

Both are correct.  Two lines of debug output from libspice-server not
shown.

Now EOF socat's standard input to make it close the connection.  This
makes the asynchronous client_migrate_info complete.  It replies:

    {"return": {}}

Bug: "id": "i1" is missing.  Two lines of debug output from
libspice-server not shown.  Cherry on top: storage for the missing ID
is leaked.

Get rid of this stuff before somebody hurts himself with it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-06-02 09:59:13 +02:00

64 lines
2.2 KiB
C

#ifndef MONITOR_H
#define MONITOR_H
#include "qemu-common.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qdict.h"
#include "block/block.h"
#include "qemu/readline.h"
extern Monitor *cur_mon;
extern Monitor *default_mon;
/* flags for monitor_init */
#define MONITOR_IS_DEFAULT 0x01
#define MONITOR_USE_READLINE 0x02
#define MONITOR_USE_CONTROL 0x04
#define MONITOR_USE_PRETTY 0x08
int monitor_cur_is_qmp(void);
void monitor_init(CharDriverState *chr, int flags);
int monitor_suspend(Monitor *mon);
void monitor_resume(Monitor *mon);
int monitor_read_bdrv_key_start(Monitor *mon, BlockDriverState *bs,
BlockCompletionFunc *completion_cb,
void *opaque);
int monitor_read_block_device_key(Monitor *mon, const char *device,
BlockCompletionFunc *completion_cb,
void *opaque);
int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp);
int monitor_fd_param(Monitor *mon, const char *fdname, Error **errp);
void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
GCC_FMT_ATTR(2, 0);
void monitor_printf(Monitor *mon, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
void monitor_flush(Monitor *mon);
int monitor_set_cpu(int cpu_index);
int monitor_get_cpu_index(void);
void monitor_set_error(Monitor *mon, QError *qerror);
void monitor_read_command(Monitor *mon, int show_prompt);
int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
void *opaque);
int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
int qmp_object_add(Monitor *mon, const QDict *qdict, QObject **ret);
void object_add(const char *type, const char *id, const QDict *qdict,
Visitor *v, Error **errp);
AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id,
bool has_opaque, const char *opaque,
Error **errp);
int monitor_fdset_get_fd(int64_t fdset_id, int flags);
int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd);
void monitor_fdset_dup_fd_remove(int dup_fd);
int monitor_fdset_dup_fd_find(int dup_fd);
#endif /* !MONITOR_H */