Make negotiation optional in QEMUMonitorProtocol

This is a preparation for qemu-ga-client which uses
QEMUMonitorProtocol class. The class tries to
negotiate capabilities on connect, however, qemu-ga
doesn't suppose it and fails.

This change makes the negotiation optional, though
it's still performed by default for compatibility.

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Support settimeout in QEMUMonitorProtocol

This method is used in the following qemu-ga-client script
to implement non-blocking operations.

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Add qemu-ga-client script

This is an easy-to-use QEMU guest agent client written in
Python. It simply provides commands to call guest agent
functions like ping, fsfreeze and shutdown. Additionally,
it provides extra useful commands, e.g, cat, ifconfig and
reboot, by using guet agent functions.

Examples:
  $ export QGA_CLIENT_ADDRESS=/tmp/qga.sock
  $ qemu-ga-client ping

  $ qemu-ga-client cat /etc/resolv.conf
  # Generated by NetworkManager
  nameserver 10.0.2.3

  $ qemu-ga-client fsfreeze status
  thawed
  $ qemu-ga-client fsfreeze freeze
  2 filesystems frozen

The script communicates with a guest agent by means of
qmp.QEMUMonitorProtocol. Every commands are called with
timeout (3 sec.) to avoid blocking. The script always
calls sync command prior to issuing an actual command
(except for ping which doesn't need sync).

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
qapi: do not protect enum values from namespace pollution

Enum values are always preceded by the uppercase name of the enum, so
they do not conflict with reserved words.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
qapi: add "unix" to the set of reserved words

It is #defined to 1.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
pci-assign: use monitor_handle_fd_param

There is no need to open-code the choice between a file descriptor
number or a named one.  Just use monitor_handle_fd_param, which
also takes care of printing the error message.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
monitor: add Error * argument to monitor_get_fd

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
qapi: convert add_client

Also fixes a few issues while there:

 1. The fd returned by monitor_get_fd() leaks in most error conditions
 2. monitor_get_fd() return value is not checked. Best case we get
    an error that is not correctly reported, worse case one of the
    functions using the fd (with value of -1) will explode
 3. A few error conditions aren't reported
 4. We now "use up" @fdname always.  Before, it was left alone for
    invalid @protocol

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
qmp: dump-guest-memory: improve schema doc (again)

 o Add a note about memory allocation with paging=true
 o Fix indentation

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
qmp: dump-guest-memory: don't spin if non-blocking fd would block

fd_write_vmcore() will indefinitely spin for a non-blocking
file-descriptor that would block. However, if the fd is non-blocking,
how does it make sense to spin?

Change this behavior to return an error instead.

Note that this can only happen with an fd provided by a management
application. The fd opened internally by dump-guest-memory is blocking.

While there, also fix 'writen_size' variable name.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
hmp: dump-guest-memory: hardcode protocol argument to "file:"

Today, it's necessary to specify the protocol you want to use
when dumping the guest memory, for example:

 (qemu) dump-guest-memory file:/tmp/guest-memory

This has a few issues:

 1. It's cumbersome to type
 2. We loose file path autocompletion
 3. Being able to specify fd:X in HMP makes little sense for humans

Because of these reasons, hardcode the 'protocol' argument to
'file:' in HMP.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
input: qmp_send_key(): simplify

The current code duplicates the QKeyCodeList keys in order to store
the key values for release_keys() late run. This is a bit complicated
though, as we have to care about correct ordering and then release_keys()
will have to index key_defs[] over again.

Switch to an array of integers, which is dynamically allocated and stores
the already converted key value.

This simplifies the current code and the next commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
qmp: qmp_send_key(): accept key codes in hex

Before the qapi conversion, the sendkey command could be used to
send key codes in hex directly to the guest. In HMP, this would
be like:

 (qemu) sendkey 0xdc

However, the qapi conversion broke this, as it only supports sending
QKeyCode values to the guest. That's a regression.

This commit fixes the problem by adding hex value support down
the QMP interface, qmp_send_key().

In more detail, this commit:

 1. Adds the KeyValue union. This can represent an hex value or
    a QKeyCode value

 2. *Changes* the QMP send-key command to take an KeyValue argument
    instead of a QKeyCode one

 3. Adapt hmp_send_key() to the QMP interface changes

Item 2 is an incompatible change, but as we're in development phase
(and this command has been merged a few weeks ago) this shouldn't be
a problem.

Finally, it's not possible to split this commit without breaking the
build.

Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
input: index_from_key(): drop unused code

The hex key conversion is unused since last commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
block: live snapshot documentation tweaks

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
error: add error_set_errno and error_setg_errno

These functions help maintaining homogeneous formatting of error
messages that include strerror values.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu-sockets: add Error ** to all functions

This lets me adjust the clients to do proper error propagation first,
thus avoiding temporary regressions in the quality of the error messages.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu-sockets: unix_listen and unix_connect are portable

They are just wrappers and do not need a Win32-specific version.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu-sockets: add nonblocking connect for Unix sockets

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hmp: rename MigrationStatus to MigrationStatusData

The name MigrationStatus will be taken by an enum.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>