qemu-ga: Convert invocation documentation to rST

The qemu-ga documentation is currently in qemu-ga.texi in
Texinfo format, which we present to the user as:
 * a qemu-ga manpage
 * a section of the main qemu-doc HTML documentation

Convert the documentation to rST format, and present it to
the user as:
 * a qemu-ga manpage
 * part of the interop/ Sphinx manual

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Message-id: 20190905131040.8350-1-peter.maydell@linaro.org

docs/conf.py

@@ -115,6 +115,14 @@ todo_include_todos = False
 # with "option::" in the document being processed. Turn that off.
 suppress_warnings = ["ref.option"]
 
+# The rst_epilog fragment is effectively included in every rST file.
+# We use it to define substitutions based on build config that
+# can then be used in the documentation. The fallback if the
+# environment variable is not set is for the benefit of readthedocs
+# style document building; our Makefile always sets the variable.
+confdir = os.getenv('CONFDIR', "/etc/qemu")
+rst_epilog = ".. |CONFDIR| replace:: ``" + confdir + "``\n"
+
 # -- Options for HTML output ----------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
@@ -192,14 +200,8 @@ latex_documents = [
 
 
 # -- Options for manual page output ---------------------------------------
-
-# One entry per manual page. List of tuples
-# (source start file, name, description, authors, manual section).
-man_pages = [
-    (master_doc, 'qemu', u'QEMU Documentation',
-     [author], 1)
-]
-
+# Individual manual/conf.py can override this to create man pages
+man_pages = []
 
 # -- Options for Texinfo output -------------------------------------------
 

docs/interop/conf.py

@@ -13,3 +13,10 @@ exec(compile(open(parent_config, "rb").read(), parent_config, 'exec'))
 # This slightly misuses the 'description', but is the best way to get
 # the manual title to appear in the sidebar.
 html_theme_options['description'] = u'System Emulation Management and Interoperability Guide'
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    ('qemu-ga', 'qemu-ga', u'QEMU Guest Agent',
+     ['Michael Roth <mdroth@linux.vnet.ibm.com>'], 8)
+]

docs/interop/index.rst

@@ -15,5 +15,6 @@ Contents:
    bitmaps
    live-block-operations
    pr-helper
+   qemu-ga
    vhost-user
    vhost-user-gpu

docs/interop/qemu-ga.rst

@@ -0,0 +1,133 @@
+QEMU Guest Agent
+================
+
+Synopsis
+--------
+
+**qemu-ga** [*OPTIONS*]
+
+Description
+-----------
+
+The QEMU Guest Agent is a daemon intended to be run within virtual
+machines. It allows the hypervisor host to perform various operations
+in the guest, such as:
+
+- get information from the guest
+- set the guest's system time
+- read/write a file
+- sync and freeze the filesystems
+- suspend the guest
+- reconfigure guest local processors
+- set user's password
+- ...
+
+qemu-ga will read a system configuration file on startup (located at
+|CONFDIR|\ ``/qemu-ga.conf`` by default), then parse remaining
+configuration options on the command line. For the same key, the last
+option wins, but the lists accumulate (see below for configuration
+file format).
+
+Options
+-------
+
+.. program:: qemu-ga
+
+.. option:: -m, --method=METHOD
+
+  Transport method: one of ``unix-listen``, ``virtio-serial``, or
+  ``isa-serial`` (``virtio-serial`` is the default).
+
+.. option:: -p, --path=PATH
+
+  Device/socket path (the default for virtio-serial is
+  ``/dev/virtio-ports/org.qemu.guest_agent.0``,
+  the default for isa-serial is ``/dev/ttyS0``)
+
+.. option:: -l, --logfile=PATH
+
+  Set log file path (default is stderr).
+
+.. option:: -f, --pidfile=PATH
+
+  Specify pid file (default is ``/var/run/qemu-ga.pid``).
+
+.. option:: -F, --fsfreeze-hook=PATH
+
+  Enable fsfreeze hook. Accepts an optional argument that specifies
+  script to run on freeze/thaw. Script will be called with
+  'freeze'/'thaw' arguments accordingly (default is
+  |CONFDIR|\ ``/fsfreeze-hook``). If using -F with an argument, do
+  not follow -F with a space (for example:
+  ``-F/var/run/fsfreezehook.sh``).
+
+.. option:: -t, --statedir=PATH
+
+  Specify the directory to store state information (absolute paths only,
+  default is ``/var/run``).
+
+.. option:: -v, --verbose
+
+  Log extra debugging information.
+
+.. option:: -V, --version
+
+  Print version information and exit.
+
+.. option:: -d, --daemon
+
+  Daemonize after startup (detach from terminal).
+
+.. option:: -b, --blacklist=LIST
+
+  Comma-separated list of RPCs to disable (no spaces, ``?`` to list
+  available RPCs).
+
+.. option:: -D, --dump-conf
+
+  Dump the configuration in a format compatible with ``qemu-ga.conf``
+  and exit.
+
+.. option:: -h, --help
+
+  Display this help and exit.
+
+Files
+-----
+
+
+The syntax of the ``qemu-ga.conf`` configuration file follows the
+Desktop Entry Specification, here is a quick summary: it consists of
+groups of key-value pairs, interspersed with comments.
+
+::
+
+    # qemu-ga configuration sample
+    [general]
+    daemonize = 0
+    pidfile = /var/run/qemu-ga.pid
+    verbose = 0
+    method = virtio-serial
+    path = /dev/virtio-ports/org.qemu.guest_agent.0
+    statedir = /var/run
+
+The list of keys follows the command line options:
+
+=============  ===========
+Key             Key type
+=============  ===========
+daemon         boolean
+method         string
+path           string
+logfile        string
+pidfile        string
+fsfreeze-hook  string
+statedir       string
+verbose        boolean
+blacklist      string list
+=============  ===========
+
+See also
+--------
+
+:manpage:`qemu(1)`