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  1. May 28, 2022
  3. Apr 21, 2022
  5. Apr 20, 2022
  7. Mar 22, 2022
  9. Mar 04, 2022
    • Hanna Reitz's avatar
      qsd: Add --daemonize · 2525edd8
      Hanna Reitz authored 
      
To implement this, we reuse the existing daemonizing functions from the
system emulator, which mainly do the following:
- Fork off a child process, and set up a pipe between parent and child
- The parent process waits until the child sends a status byte over the
  pipe (0 means that the child was set up successfully; anything else
  (including errors or EOF) means that the child was not set up
  successfully), and then exits with an appropriate exit status
- The child process enters a new session (forking off again), changes
  the umask, and will ignore terminal signals from then on
- Once set-up is complete, the child will chdir to /, redirect all
  standard I/O streams to /dev/null, and tell the parent that set-up has
  been completed successfully

In contrast to qemu-nbd's --fork implementation, during the set up
phase, error messages are not piped through the parent process.
qemu-nbd mainly does this to detect errors, though (while os_daemonize()
has the child explicitly signal success after set up); because we do not
redirect stderr after forking, error messages continue to appear on
whatever the parent's stderr was (until set up is complete).

Signed-off-by: default avatarHanna Reitz <hreitz@redhat.com>
Message-Id: <20220303164814.284974-4-hreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      2525edd8
    • Hanna Reitz's avatar
      qsd: Add pre-init argument parsing pass · 79d51d73
      Hanna Reitz authored 
      
In contrast to qemu-nbd (where it is called --fork) and the system
emulator, QSD does not have a --daemonize switch yet.  Just like them,
QSD allows setting up block devices and exports on the command line.
When doing so, it is often necessary for whoever invoked the QSD to wait
until these exports are fully set up.  A --daemonize switch allows
precisely this, by virtue of the parent process exiting once everything
is set up.

Note that there are alternative ways of waiting for all exports to be
set up, for example:
- Passing the --pidfile option and waiting until the respective file
  exists (but I do not know if there is a way of implementing this
  without a busy wait loop)
- Set up some network server (e.g. on a Unix socket) and have the QSD
  connect to it after all arguments have been processed by appending
  corresponding --chardev and --monitor options to the command line,
  and then wait until the QSD connects

Having a --daemonize option would make this simpler, though, without
having to rely on additional tools (to set up a network server) or busy
waiting.

Implementing a --daemonize switch means having to fork the QSD process.
Ideally, we should do this as early as possible: All the parent process
has to do is to wait for the child process to signal completion of its
set-up phase, and therefore there is basically no initialization that
needs to be done before the fork.  On the other hand, forking after
initialization steps means having to consider how those steps (like
setting up the block layer or QMP) interact with a later fork, which is
often not trivial.

In order to fork this early, we must scan the command line for
--daemonize long before our current process_options() call.  Instead of
adding custom new code to do so, just reuse process_options() and give
it a @pre_init_pass argument to distinguish the two passes.  I believe
there are some other switches but --daemonize that deserve parsing in
the first pass:

- --help and --version are supposed to only print some text and then
  immediately exit (so any initialization we do would be for naught).
  This changes behavior, because now "--blockdev inv-drv --help" will
  print a help text instead of complaining about the --blockdev
  argument.
  Note that this is similar in behavior to other tools, though: "--help"
  is generally immediately acted upon when finding it in the argument
  list, potentially before other arguments (even ones before it) are
  acted on.  For example, "ls /does-not-exist --help" prints a help text
  and does not complain about ENOENT.

- --pidfile does not need initialization, and is already exempted from
  the sequential order that process_options() claims to strictly follow
  (the PID file is only created after all arguments are processed, not
  at the time the --pidfile argument appears), so it makes sense to
  include it in the same category as --daemonize.

- Invalid arguments should always be reported as soon as possible.  (The
  same caveat with --help applies: That means that "--blockdev inv-drv
  --inv-arg" will now complain about --inv-arg, not inv-drv.)

This patch does make some references to --daemonize without having
implemented it yet, but that will happen in the next patch.

Signed-off-by: default avatarHanna Reitz <hreitz@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20220303164814.284974-3-hreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      79d51d73
  11. Feb 01, 2022
  13. Jan 14, 2022
  15. Oct 29, 2021
  17. Oct 06, 2021
  19. Aug 11, 2021
  21. Mar 29, 2021
    • Hanna Reitz's avatar
      qsd: Document FUSE exports · 220222a0
      Hanna Reitz authored 
      
Implementing FUSE exports required no changes to the storage daemon, so
we forgot to document them there.  Considering that both NBD and
vhost-user-blk exports are documented in its man page (and NBD exports
in its --help text), we should probably do the same for FUSE.

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Message-Id: <20210217115844.62661-1-mreitz@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
      220222a0
  23. Mar 19, 2021
  25. Mar 08, 2021
  27. Feb 15, 2021
  29. Feb 02, 2021
  31. Jan 12, 2021
  33. Dec 18, 2020
    • Stefan Hajnoczi's avatar
      docs: generate qemu-storage-daemon-qmp-ref(7) man page · 23c02ace
      Stefan Hajnoczi authored 
      
Although individual qemu-storage-daemon QMP commands are identical to
QEMU QMP commands, qemu-storage-daemon only supports a subset of QEMU's
QMP commands. Generate a manual page of just the commands supported by
qemu-storage-daemon so that users know exactly what is available in
qemu-storage-daemon.

Add an h1 heading in storage-daemon/qapi/qapi-schema.json so that
block-core.json is at the h2 heading level.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201209103802.350848-2-stefanha@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      23c02ace
  35. Dec 11, 2020
  37. Nov 11, 2020
  39. Oct 23, 2020
  41. Oct 15, 2020
    • Kevin Wolf's avatar
      qemu-storage-daemon: Remove QemuOpts from --object parser · 8db1efd3
      Kevin Wolf authored 
      
The command line parser for --object parses the input twice: Once into
QemuOpts just for detecting help options, and then again into a QDict
using the keyval parser for actually creating the object.

Now that the keyval parser can also detect help options, we can simplify
this and remove the QemuOpts part.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20201007164903.282198-5-kwolf@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      8db1efd3
    • Kevin Wolf's avatar
      keyval: Parse help options · 8bf12c4f
      Kevin Wolf authored 
      
This adds a special meaning for 'help' and '?' as options to the keyval
parser. Instead of being an error (because of a missing value) or a
value for an implied key, they now request help, which is a new boolean
output of the parser in addition to the QDict.

A new parameter 'p_help' is added to keyval_parse() that contains on
return whether help was requested. If NULL is passed, requesting help
results in an error and all other cases work like before.

Turning previous error cases into help is a compatible extension. The
behaviour potentially changes for implied keys: They could previously
get 'help' as their value, which is now interpreted as requesting help.

This is not a problem in practice because 'help' and '?' are not a valid
values for the implied key of any option parsed with keyval_parse():

* audiodev: union Audiodev, implied key "driver" is enum AudiodevDriver,
  "help" and "?" are not among its values

* display: union DisplayOptions, implied key "type" is enum
  DisplayType, "help" and "?" are not among its values

* blockdev: union BlockdevOptions, implied key "driver is enum
  BlockdevDriver, "help" and "?" are not among its values

* export: union BlockExport, implied key "type" is enum BlockExportType,
  "help" and "?" are not among its values

* monitor: struct MonitorOptions, implied key "mode" is enum MonitorMode,
  "help" and "?" are not among its values

* nbd-server: struct NbdServerOptions, no implied key.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20201011073505.1185335-5-armbru@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      8bf12c4f
  43. Oct 02, 2020
  45. Sep 29, 2020
    • Peter Maydell's avatar
      docs/interop: Convert qemu-qmp-ref to rST · 4ac2ee19
      Peter Maydell authored 
      
Convert qemu-qmp-ref to rST format. This includes dropping
the plain-text, pdf and info format outputs for this document;
as with all our other Sphinx-based documentation, we provide
HTML and manpage only.

The qemu-qmp-ref.rst is somewhat more stripped down than
the .texi was, because we do not (currently) attempt to
generate indexes for the commands, events and data types
being documented.

Again, we drop the direct link from index.html.in now that
the QMP ref is part of the interop manual.

This commit removes the code from the root meson.build file that
handled the various Texinfo-based outputs, because we no longer
generate any documentation except for the Sphinx HTML manuals and the
manpages, and the code can't handle having an empty list of files
to process.. We'll do further cleanup of the remainders of
Texinfo support in subsequent commits.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-10-peter.maydell@linaro.org>
Reviewed-by: default avatarMarkus Armbruster <armbru@redhat.com>
[Unicode legacy literal dumbed down to plain string literal, TODO
comment on displaying QEMU version added, "make html" fixed,
storage-daemon/qapi/meson.build updated]
Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
      4ac2ee19
  47. Aug 21, 2020
    • Paolo Bonzini's avatar
      meson: convert qemu-storage-daemon · 7c58bb76
      Paolo Bonzini authored 
      
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7c58bb76
    • Paolo Bonzini's avatar
      libqemuutil, qapi, trace: convert to meson · a81df1b6
      Paolo Bonzini authored 
      
This shows how to do some "computations" in meson.build using its array
and dictionary data structures, and also a basic usage of the sourceset
module for conditional compilation.

Notice the new "if have_system" part of util/meson.build, which fixes
a bug in the old build system was buggy: util/dbus.c was built even for
non-softmmu builds, but the dependency on -lgio was lost when the linking
was done through libqemuutil.a.  Because all of its users required gio
otherwise, the bug was hidden.  Meson instead propagates libqemuutil's
dependencies down to its users, and shows the problem.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a81df1b6