Current KDE prevents Server GUI from exiting

[rdica]

Discussed in https://github.com/orgs/jamulussoftware/discussions/3006

^{Originally posted by pcar75 February 9, 2023}
Bonjour,
On my dual boot PC, I can shutdown Jamulus server in Windows 10. However I can't do that in Linux, because I believe it installs itself as a service. Is there a nicer (GUI) way of shuting down Jamulus server, instead of running a script or terminal with killall -I "jamulus" ?

Context : dual Boot PC : Windows 10 / Ubuntu Studio 22.04.1 LTS (Plasma KDE).
On Windows
Jamulus server (3.9.1) with GUI
Menu > Window > Exit (Ctrl+Q) : OK terminates process & threads
X Button : OK terminates process & threads
On Ubuntu Studio 22.04.1 LTS
Jamulus server (3.9.1) with GUI and Icon in system tray bar
Menu > Window > Exit (Ctrl+Q) : Hides GUI only
X (Close) Button : Hides GUI only
Sys tray Exit (Icon menu buttons = Exit, Show, Hide...) : Hides GUI if it was visible ( ~ Exit ICON menu).

EDIT : added precision : Ubuntu Studio 22.04.1 LTS and Qt is 5.15.3 as mentioned below (rdica).

It seems that latest KDE on at least Ubuntu 22.04+ and Fedora37 has introduced a change that prevents exiting the server process when the server GUI is started. Exiting merely closes the GUI window, but leaves the tray icon running as well as the server process itself.

As noted in the original discussion thread, disabling the tray icon functionality returns proper exit behaviour.
Personally I feel this is a bug and as current and future linux distros using KDE desktops will continue to experience the problem, it should be addressed as such, however it's been deemed not a bug, so the following request.

Request that either the tray icon be removed altogether, or a toggle be added to disable it.

Thanks!

[pljones]

@rdica does this happen if you run the Jamulus server GUI from a shell prompt? Or is it only if you use the provided desktop shortcut?

(I run my Linux KDE desktop remoted to Windows over VcXsvr and I can't reproduce the problem - I don't use the KDE desktop itself, though - just the windows, managed by MS Windows 11.)

[rdica]

@pljones Yes, also happens when started from shell prompt.

[pljones]

Thanks. Can you write down the full command line you use?

[rdica]

jamulus -s

[pljones]

OK.

• Run the server GUI as above and then in another terminal do ps -ef | grep "jamulus -s" and paste the results
• Use "Window -> Exit" (or Ctrl+Q) in the server GUI to exit and then in the other terminal do ps -ef | grep "jamulus -s" and paste the results again

Thanks.

[rdica]

Startup:

ardy@daw1:~$ ps -ef|grep "jamulus -s"
ardy        7762    3240  1 12:21 pts/2    00:00:00 jamulus -s

After closing:

ardy@daw1:~$ ps -ef|grep "jamulus -s"
ardy        7762    3240  0 12:21 pts/2    00:00:00 jamulus -s

[pljones]

Strange... Can you do ls -l .config/Jamulus/ and paste here, please.

[rdica]

ardy@daw1:~$ ls -l .config/Jamulus/
total 376
-rw-rw-r-- 1 ardy ardy 74660 Aug 12 22:24 Jamulus.ini
-rw-rw-r-- 1 ardy ardy 74616 Mar  1 13:42 Jamulus.ini-bak-20230228
-rw-rw-r-- 1 ardy ardy 72061 Jan 22  2023 Jamulus.ini.orig
-rw-rw-r-- 1 ardy ardy   547 Aug 13 12:28 Jamulusserver.ini
-rw-rw-r-- 1 ardy ardy 74053 Jul 31 18:42 KEYS.ini
-rw-rw-r-- 1 ardy ardy 72123 Feb 13 13:47 test.ini

cat .config/Jamulus/Jamulusserver.ini 
<server>
 <winposmain_base64>AdnQywADAAAAAAUWAAAAOwAAB2EAAALBAAAFFgAAADsAAAdhAAACwQAAAAAAAAAAB4AAAAUWAAAAOwAAB2EAAALB</winposmain_base64>
 <directorytype>-1</directorytype>
 <name>Disabled Icon Tray</name>
 <city>Home</city>
 <country>225</country>
 <norecord>0</norecord>
 <welcome>VWJ1bnR1IFN0dWRpbyAyMi4wNA==</welcome>
 <language>en</language>
 <recordingdir_base64></recordingdir_base64>
 <directoryaddress></directoryaddress>
 <directoryfile_base64></directoryfile_base64>
 <autostartmin>0</autostartmin>
 <delaypan>1</delaypan>
</server>

[pljones]

Right... digging deeper (and getting out of my depth :) )...

Could you run Jamulus Server with strace, catching all the output:

strace jamulus -s > log 2>&1

then hit Ctrl-Q to quit once the window opens. Then run

grep -v '^\(writev\|getrandom\|futex\|brk\|poll\|recvmsg\|mmap\|munmap\|mprotect\|.*fonts\|.*fontconfig\|.*opt.Qt\|read.*ELF\|.*\.so\.\)' log | tail -40

to see the last 40 lines of the log (with boring bits removed) and paste the result, please.

(Or drag-n-drop the log file complete.)

[rdica]

Did the latter as I couldn't ensure the last 40 lines would reflect attempt to close. File created using strace -o jamulusserver.log jamulus -s, then attempt to close window, then exit program.

jamulusserver.log

[pljones]

It looks like it exits normally from the strace output:

socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE) = 28
bind(28, {sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, 12) = 0
getsockname(28, {sa_family=AF_NETLINK, nl_pid=51797, nl_groups=00000000}, [12]) = 0
sendto(28, [{nlmsg_len=20, nlmsg_type=RTM_GETADDR, nlmsg_flags=NLM_F_REQUEST|NLM_F_DUMP, nlmsg_seq=1692041884, nlmsg_pid=0}, {ifa_family=AF_UNSPEC, ...}], 20, 0, {sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, 12) = 20
close(28)                               = 0
newfstatat(AT_FDCWD, "/etc/nsswitch.conf", {st_mode=S_IFREG|0644, st_size=542, ...}, 0) = 0
newfstatat(AT_FDCWD, "/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=933, ...}, 0) = 0
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 28
newfstatat(28, "", {st_mode=S_IFREG|0644, st_size=302, ...}, AT_EMPTY_PATH) = 0
lseek(28, 0, SEEK_SET)                  = 0
read(28, "# Standard host addresses\n127.0."..., 4096) = 302
read(28, "", 4096)                      = 0
close(28)                               = 0
socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 28
setsockopt(28, SOL_IP, IP_RECVERR, [1], 4) = 0
connect(28, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, 16) = 0
sendmmsg(28, [{msg_hdr={msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\253\223\1 \0\1\0\0\0\0\0\1\tanygenre1\7jamulus\2i"..., iov_len=49}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, msg_len=49}, {msg_hdr={msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\r\225\1 \0\1\0\0\0\0\0\1\tanygenre1\7jamulus\2i"..., iov_len=49}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, msg_len=49}], 2, MSG_NOSIGNAL) = 2
ioctl(28, FIONREAD, [108])              = 0
recvfrom(28, "\253\223\201\200\0\1\0\2\0\0\0\1\tanygenre1\7jamulus\2i"..., 2048, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, [28 => 16]) = 108
ioctl(28, FIONREAD, [162])              = 0
recvfrom(28, "\r\225\201\200\0\1\0\1\0\1\0\1\tanygenre1\7jamulus\2i"..., 65536, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, [28 => 16]) = 162
close(28)                               = 0
write(2, "Server Registration Status updat"..., 50) = 50
sendto(12, "\0\0\355\3\0\0\0\233\217", 9, 0, {sa_family=AF_INET, sin_port=htons(22124), sin_addr=inet_addr("62.113.204.104")}, 16) = 9
openat(AT_FDCWD, "/home/ardy/.config/Jamulus/Jamulusserver.ini", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 28
statx(28, "", AT_STATX_SYNC_AS_STAT|AT_EMPTY_PATH, STATX_ALL, {stx_mask=STATX_ALL|STATX_MNT_ID, stx_attributes=0, stx_mode=S_IFREG|0664, stx_size=0, ...}) = 0
write(28, "<server>\n <winposmain_base64>Adn"..., 543) = 543
close(28)                               = 0
shutdown(12, SHUT_RDWR)                 = -1 ENOTCONN (Transport endpoint is not connected)
close(12)                               = 0
msync(0x7f56494b4000, 10547304, MS_ASYNC|MS_INVALIDATE) = 0
rt_sigaction(SIGUSR1, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f5667d9d520}, NULL, 8) = 0
rt_sigaction(SIGUSR2, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f5667d9d520}, NULL, 8) = 0
rt_sigaction(SIGINT, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f5667d9d520}, NULL, 8) = 0
rt_sigaction(SIGTERM, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f5667d9d520}, NULL, 8) = 0
getpid()                                = 51797
getpid()                                = 51797
getpid()                                = 51797
exit_group(0)                           = ?
+++ exited with 0 +++

exit_group(0) doesn't return but the exited with 0 indicates the forked jamulus command return to strace okay. (I think...)

Is it still running after running with strace like that?

[rdica]

Yes, and I can connect to it (tray icon shows a little green dot when a client is connected).

[pljones]

And if you do ps -ef | grep 'jamulus -s' whilst the server is running, is the PID reported by getpid just before exit_group in the strace output the same as the pid of the running server?

[rdica]

Yes.
It should be noted in case you weren't aware, that exit_group event at the end of the strace log is when I ctrl+c out of the strace, not when I attempt the window close.

[pljones]

Oh - it doesn't exit cleanly from the strace on Ctrl-Q? Interesting... It should.

[rdica]

Well no, ctrl+q etc doesnt exit the program, thats the problem :)
Starting jamulus -s from cli doesn't fork and return to prompt, hence the need to ctrl+c out.

I'm not familiar enough with strace log output to determine where in the log the attempt to close the window is.

[pljones]

Could you run the strace and attach the log up to the point where you hit Ctrl-Q, please.

[rdica]

This was as close as I could get the exit attempt without the trailing ctrl+c exit.

debug-jamulusserver.log

[pljones]

Could you post the whole log or is it too big?

[rdica]

I created a new log file using strace -o debug-jamulusserver.log jamulus -s, the exit at the end is where I ctrl+c.

debug-jamulusserver.log

[pljones]

I need it as soon as possible where you hit Ctrl-Q - just copy the file at that point to another and attach that. Otherwise I can't see what happens between the Ctrl-Q and Ctrl-C. (There may be a strace flag to get it not to buffer writes. If so, use that so the file is as up to date as possible.)

[rdica]

Based on the number of lines per timestamp, I think what you want begins at 10:58:05.

for i in 0 1 2 3 4 5 6 7; do echo -n "10:58:0${i}: ";grep "10:58:0${i}" debug_jamulusserver.log |wc -l;done
10:58:00: 25
10:58:01: 25
10:58:02: 25
10:58:03: 27
10:58:04: 25
10:58:05: 49
10:58:06: 174
10:58:07: 262

debug_jamulusserver.log

[pljones]

src/serverdlg.cpp:    pViewMenu->addAction ( tr ( "E&xit" ), this, SLOT ( close() ), QKeySequence ( Qt::CTRL + Qt::Key_Q ) );

Each window in Jamulus is a Qt QDialog and we attempt to route the signal from File->Exit or Ctrl+Q to the close() slot on the dialog. In fact, close() is on the QWidget class from which QDialog inherits.

The QGuiApplication::lastWindowClosed() signal is emitted when the last visible primary window (i.e. window with no parent) with the Qt::WA_QuitOnClose attribute set is closed. By default this attribute is set for all widgets except transient windows such as splash screens, tool windows, and popup menus.

By default, QGuiApplication quits after this signal is emitted. This feature can be turned off by setting quitOnLastWindowClosed to false.

Jamulus doesn't set WA_QuitOnClose on the dialog or quitOnLastWindowClosed to false. So I'm not sure why the current code isn't working in KDE.

I couldn't see anything in the log to indicate the close() had occurred. It's probably worth wrapping the close() call in a method with some logging in to see whether the menu entry / keystroke is even arriving.

[rdica]

If you create a patch, I can apply it against the src and compile it and test it against the KDE ver shipped with Ubuntu Studio 22.04.

[pljones]

I'll have a go for 3.11.0.

[pljones]

Moved out to 3.12.0.