[Spice-devel] [PATCH spice-streaming-agent 5/5] Provide helper to give information to daemon

[Frediano Ziglio]

> 
> On Thu, 2018-02-01 at 16:40 +0000, Frediano Ziglio wrote:
> > This is required so the daemon can manage the various sessions.
> 
> At first glance, this looks like a really big hack. At second glance, I
> understand why you did it... (doesn't mean I like it now ;)) But in any
> case this deserves a much better description... well, preferably in the
> code, not (only) commit message.
> 
> Also, I would really like to think of a better way of doing this. Seems
> the streaming agent is starting to have quite a lot of moving parts...
> 
> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> > ---
> >  data/spice-streaming.desktop.in |  3 +--
> >  spice-streaming-agent.spec.in   |  1 +
> >  src/Makefile.am                 |  5 +++++
> >  src/spice-streaming-helper      | 24 ++++++++++++++++++++++++
> >  4 files changed, 31 insertions(+), 2 deletions(-)
> >  create mode 100755 src/spice-streaming-helper
> > 
> > diff --git a/data/spice-streaming.desktop.in
> > b/data/spice-streaming.desktop.in
> > index dcb30a3..5e4e863 100644
> > --- a/data/spice-streaming.desktop.in
> > +++ b/data/spice-streaming.desktop.in
> > @@ -1,8 +1,7 @@
> >  [Desktop Entry]
> >  Name=SPICE Streaming Agent
> >  Comment=Agent for Streaming the framebuffer to Spice
> > -Exec=@BINDIR@/spice-streaming-agent
> > -#TryExec=/usr/bin/spice-streaming-agent
> > +Exec=@BINDIR@/spice-streaming-helper
> >  Terminal=false
> >  Type=Application
> >  Categories=
> > diff --git a/spice-streaming-agent.spec.in b/spice-streaming-agent.spec.in
> > index eef8f90..54a3598 100644
> > --- a/spice-streaming-agent.spec.in
> > +++ b/spice-streaming-agent.spec.in
> > @@ -54,6 +54,7 @@ fi
> >  %doc COPYING ChangeLog README
> >  %{_udevrulesdir}/90-spice-guest-streaming.rules
> >  %{_bindir}/spice-streaming-agent
> > +%{_bindir}/spice-streaming-helper
> >  %{_sysconfdir}/xdg/autostart/spice-streaming.desktop
> >  %{_datadir}/gdm/greeter/autostart/spice-streaming.desktop
> >  /usr/lib/systemd/system/spice-streaming-agent.socket
> 
> Does this add dependency on Python 3? Should it be added somewhere in
> this file?
> 

Usually the RPM script are smart enough nowadays to understand.
I'll check.

> > diff --git a/src/Makefile.am b/src/Makefile.am
> > index d2f8a47..9e9c7e7 100644
> > --- a/src/Makefile.am
> > +++ b/src/Makefile.am
> > @@ -5,6 +5,7 @@
> >  
> >  NULL =
> >  SUBDIRS = . unittests
> > +EXTRA_DIST =
> >  
> >  AM_CPPFLAGS = \
> >  	-DSPICE_STREAMING_AGENT_PROGRAM \
> > @@ -61,3 +62,7 @@ spice_streaming_agent_SOURCES = \
> >  	daemon.cpp \
> >  	daemon.h \
> >  	$(NULL)
> > +
> > +helperdir = $(bindir)
> > +helper_SCRIPTS = spice-streaming-helper
> > +EXTRA_DIST += spice-streaming-helper
> > diff --git a/src/spice-streaming-helper b/src/spice-streaming-helper
> > new file mode 100755
> > index 0000000..beba559
> > --- /dev/null
> > +++ b/src/spice-streaming-helper
> > @@ -0,0 +1,24 @@
> > +#!/usr/bin/env python3
> > +import os
> > +import socket
> > +import sys
> > +import struct
> > +
> 
> I am not sure how mandatory this actually is in Python, but I would
> prefer to have this here:
> if __name__ == "__main__":
>     main()
> 

not mandatory, helps for bigger programs or in a library.

> > +sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
> > +
> > +server_address = "\0spice-streaming-agent-daemon"
> > +def code(var, type):
> 
> Like... it's pretty obvious and the code is local here, but still...
> name the function properly? :)
> 

encode_env ?

> > +    val = os.environ.get(var, '').encode('utf-8')
> > +    return struct.pack('BB', type, len(val)) + val
> > +
> > +display = code('DISPLAY', 1)
> > +xauthority = code('XAUTHORITY', 2)
> > +
> > +try:
> > +    sock.connect(server_address)
> > +    data = struct.pack('B', 1) + display + xauthority
> > +    sock.send(data)
> > +    sock.recv(10)
> 
> What's the recv(10) for, actually?
>

To wait for reply or disconnection.
Yes, not quickly understandable, better to put a comment.
 
> > +except socket.error as msg:
> > +    print(msg, file=sys.stderr)
> > +    sys.exit(1)
>