[StereoTool] Saving presets fails

[rmens]

Description

I'm not sure if this is a Liquidsoap or StereoTool problem. But since StereoTool doesn't have a public bug tracker, I'll start here.

When loading StereoTool in Liquidsoap, there's an option to save the preset via the web interface. Which is great, since it's a pain in the ass manually editing the preset file.

Steps to reproduce

Load StereoTool via

# StereoTool implementation
radioproc =
  stereotool(
    library_file="/opt/stereotool/st_plugin.so",
    license_key=
      "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    preset="/etc/liquidsoap/st.ini",
    radio
  )

You have to define a pre-built preset with at least the web interface enabled and your ip whitelisted, otherwise it's impossible to configure StereoTool via it's web interface.

Configure the settings. Go to 'Select preset' and push 'Save current settings as preset'. This error will show up.

Expected behavior

Being able to save the preset.

Liquidsoap version

Liquidsoap 2.2.5
Copyright (c) 2003-2024 Savonet team
Liquidsoap is open-source software, released under GNU General Public License.
See <http://liquidsoap.info> for more information.

Liquidsoap build config

Liquidsoap 2.2.5
Copyright (c) 2003-2024 Savonet team
Liquidsoap is open-source software, released under GNU General Public License.
See <http://liquidsoap.info> for more information.
root@st1041:~# liquidsoap --build-config

 * Liquidsoap version  : 2.2.5

 * Compilation options
   - Release build       : true
   - Git SHA             : (none)
   - OCaml version       : 4.14.1
   - OS type             : Unix
   - Libs versions       : alsa=0.3.0 angstrom=0.15.0 ao=0.2.4 asetmap=0.8.1 asn1-combinators=0.2.6 astring=0.8.5 base64=3.5.1 bigarray=[distributed with Ocaml] bigarray-compat=1.1.0 bigstringaf=0.9.1 bjack=0.1.6 bos=0.2.1 bytes=[distributed with OCaml 4.02 or above] ca-certs=v0.2.3 camlimages.all_formats=4.2.6 camlimages.core=5.0.4 camlimages.exif=5.0.4 camlimages.gif=5.0.4 camlimages.jpeg=5.0.4 camlimages.png=5.0.4 camlimages.tiff=5.0.4 camlimages.xpm=5.0.4 camlp-streams camomile.lib=2.0 cohttp=5.3.0 cohttp-lwt=5.3.0 cohttp-lwt-unix=5.3.0 conduit=6.2.0 conduit-lwt=6.2.0 conduit-lwt-unix=6.2.0 cry=1.0.3 cstruct=6.2.0 ctypes=0.21.1 ctypes-foreign=0.21.1 ctypes.stubs=0.21.1 curl=0.9.2 domain-name=0.4.0 domain_shims dssi=0.1.5 dtools=0.4.5 dune-build-info=3.11.1 dune-private-libs.dune-section=3.11.1 dune-site=3.11.1 dune-site.private=3.11.1 duppy=0.9.4 eqaf=0.9 eqaf.bigstring=0.9 eqaf.cstruct=0.9 faad=0.5.2 fdkaac=0.3.3 ffmpeg-av=1.1.10 ffmpeg-avcodec=1.1.10 ffmpeg-avdevice=1.1.10 ffmpeg-avfilter=1.1.10 ffmpeg-avutil=1.1.10 ffmpeg-swresample=1.1.10 ffmpeg-swscale=1.1.10 fileutils=0.6.4 flac=0.5.1 flac.decoder=0.5.1 flac.ogg=0.5.1 fmt=0.9.0 fpath=0.7.3 frei0r=0.1.2 gd=1.0a5 gen=1.1 gmap=0.3.0 hkdf=1.0.4 inotify=2.4.1 integers ipaddr=5.5.0 ipaddr-sexp=5.5.0 ipaddr.unix=5.5.0 irc-client irc-client-unix jemalloc ladspa=0.2.2 lame=0.3.7 lastfm=0.3.4 lilv=0.1.0 liquidsoap-lang=2.2.5 liquidsoap-lang.console=2.2.5 liquidsoap_alsa=f0fdb0e-dirty liquidsoap_ao=f0fdb0e-dirty liquidsoap_bjack=f0fdb0e-dirty liquidsoap_builtins=f0fdb0e-dirty liquidsoap_camlimages=f0fdb0e-dirty liquidsoap_core=f0fdb0e-dirty liquidsoap_dssi=f0fdb0e-dirty liquidsoap_faad=f0fdb0e-dirty liquidsoap_fdkaac=f0fdb0e-dirty liquidsoap_ffmpeg=f0fdb0e-dirty liquidsoap_flac=f0fdb0e-dirty liquidsoap_frei0r=f0fdb0e-dirty liquidsoap_gd=f0fdb0e-dirty liquidsoap_irc=f0fdb0e-dirty liquidsoap_jemalloc=f0fdb0e-dirty liquidsoap_ladspa=f0fdb0e-dirty liquidsoap_lame=f0fdb0e-dirty liquidsoap_lastfm=f0fdb0e-dirty liquidsoap_lilv=f0fdb0e-dirty liquidsoap_lo=f0fdb0e-dirty liquidsoap_mad=f0fdb0e-dirty liquidsoap_mem_usage=f0fdb0e-dirty liquidsoap_memtrace=f0fdb0e-dirty liquidsoap_ogg=f0fdb0e-dirty liquidsoap_ogg_flac=f0fdb0e-dirty liquidsoap_optionals=f0fdb0e-dirty liquidsoap_opus=f0fdb0e-dirty liquidsoap_osc=f0fdb0e-dirty liquidsoap_oss=f0fdb0e-dirty liquidsoap_portaudio=f0fdb0e-dirty liquidsoap_posix_time=f0fdb0e-dirty liquidsoap_prometheus=f0fdb0e-dirty liquidsoap_pulseaudio=f0fdb0e-dirty liquidsoap_runtime=f0fdb0e-dirty liquidsoap_samplerate=f0fdb0e-dirty liquidsoap_sdl=f0fdb0e-dirty liquidsoap_shine=f0fdb0e-dirty liquidsoap_soundtouch=f0fdb0e-dirty liquidsoap_speex=f0fdb0e-dirty liquidsoap_srt=f0fdb0e-dirty liquidsoap_ssl=f0fdb0e-dirty liquidsoap_stereotool=f0fdb0e-dirty liquidsoap_taglib=f0fdb0e-dirty liquidsoap_theora=f0fdb0e-dirty liquidsoap_tls=f0fdb0e-dirty liquidsoap_vorbis=f0fdb0e-dirty liquidsoap_xmlplaylist=f0fdb0e-dirty liquidsoap_yaml=f0fdb0e-dirty lo=0.2.0 logs=0.7.0 logs.fmt=0.7.0 logs.lwt=0.7.0 lwt=5.7.0 lwt.unix=5.7.0 macaddr=5.5.0 mad=0.5.3 magic-mime=1.3.1 mem_usage=0.1.1 memtrace=0.2.3 menhirLib=20230608 metadata=0.3.0 mirage-crypto=0.11.2 mirage-crypto-ec=0.11.2 mirage-crypto-pk=0.11.2 mirage-crypto-rng=0.11.2 mirage-crypto-rng.unix=0.11.2 mm=0.8.5 mm.audio=0.8.5 mm.base=0.8.5 mm.image=0.8.5 mm.midi=0.8.5 mm.video=0.8.5 ocplib-endian ocplib-endian.bigstring ogg=0.7.4 ogg.decoder=0.7.4 opus=0.2.3 opus.decoder=0.2.3 osc osc-unix parsexp=v0.16.0 pbkdf pcre=7.5.0 portaudio=0.2.3 posix-base=5a7f328 posix-socket=5a7f328 posix-socket.constants=5a7f328 posix-socket.stubs=5a7f328 posix-socket.types=5a7f328 posix-time2=5a7f328 posix-time2.constants=5a7f328 posix-time2.stubs=5a7f328 posix-time2.types=5a7f328 posix-types=5a7f328 posix-types.constants=5a7f328 ppx_sexp_conv.runtime-lib=v0.16.0 prometheus=1.2 prometheus-app=1.2 ptime=1.1.0 ptime.clock.os=1.1.0 pulseaudio=0.1.6 re=1.11.0 result=1.5 rresult=0.7.0 samplerate=0.1.7 saturn_lockfree=0.4.1 sedlex=3.2 seq=[distributed with OCaml 4.07 or above] sexplib=v0.16.0 sexplib0=v0.16.0 shine=0.2.3 soundtouch=0.1.9 speex=0.4.2 speex.decoder=0.4.2 srt=0.3.1 srt.constants=0.3.1 srt.stubs=0.3.1 srt.stubs.locked=0.3.1 srt.types=0.3.1 ssl=0.7.0 stdlib-shims=0.3.0 stereotool=f0fdb0e-dirty str=[distributed with Ocaml] stringext=1.6.0 taglib=0.3.10 theora=0.4.1 theora.decoder=0.4.1 threads=[distributed with Ocaml] threads.posix=[internal] tls=0.17.1 tsdl=v1.0.0 tsdl-image=0.5 tsdl-ttf=0.6 unix=[distributed with Ocaml] unix-errno=52c6ecb unix-errno.errno_bindings=52c6ecb unix-errno.errno_types=52c6ecb unix-errno.errno_types_detected=52c6ecb unix-errno.unix=52c6ecb uri=4.4.0 uri-sexp=4.4.0 uri.services=4.4.0 vorbis=0.8.1 vorbis.decoder=0.8.1 x509=0.16.5 xmlm=1.4.0 xmlplaylist=0.1.5 yaml=3.2.0 yaml.bindings=3.2.0 yaml.bindings.types=3.2.0 yaml.c=3.2.0 yaml.ffi=3.2.0 yaml.types=3.2.0 zarith=1.13
   - architecture        : amd64
   - host                : x86_64-pc-linux-gnu
   - target              : x86_64-pc-linux-gnu
   - system              : linux
   - ocamlopt_cflags     : -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC
   - native_c_compiler   : gcc -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC -D_FILE_OFFSET_BITS=64
   - native_c_libraries  : -lm

 * Configured paths
   - mode              : posix
   - standard library  : /usr/share/liquidsoap/libs
   - scripted binaries : /usr/share/liquidsoap/bin
   - rundir            : /var/run/liquidsoap
   - logdir            : /var/log/liquidsoap
   - camomile files    : /usr/share/liquidsoap/camomile

 * Supported input formats
   - MP3               : yes
   - AAC               : yes
   - Ffmpeg            : yes
   - Flac (native)     : yes
   - Flac (ogg)        : yes
   - Opus              : yes
   - Speex             : yes
   - Theora            : yes
   - Vorbis            : yes

 * Supported output formats
   - FDK-AAC           : yes
   - Ffmpeg            : yes
   - MP3               : yes
   - MP3 (fixed-point) : yes
   - Flac (native)     : yes
   - Flac (ogg)        : yes
   - Opus              : yes
   - Speex             : yes
   - Theora            : yes
   - Vorbis            : yes

 * Tags
   - Taglib (ID3 tags) : yes
   - Vorbis            : yes

 * Input / output
   - ALSA              : yes
   - AO                : yes
   - FFmpeg            : yes
   - GStreamer         : no (requires gstreamer)
   - JACK              : yes
   - OSS               : yes
   - Portaudio         : yes
   - Pulseaudio        : yes
   - SRT               : yes

 * Audio manipulation
   - FFmpeg            : yes
   - LADSPA            : yes
   - Lilv              : yes
   - Samplerate        : yes
   - SoundTouch        : yes
   - StereoTool        : yes

 * Video manipulation
   - camlimages        : yes
   - FFmpeg            : yes
   - frei0r            : yes
   - ImageLib          : no (requires imagelib)
   - SDL               : yes

 * MIDI manipulation
   - DSSI              : yes

 * Visualization
   - GD                : yes
   - Graphics          : no (requires graphics)
   - SDL               : yes

 * Additional libraries
   - FFmpeg filters    : yes
   - FFmpeg devices    : yes
   - inotify           : yes
   - irc               : yes
   - jemalloc          : yes
   - lastfm            : yes
   - lo                : yes
   - memtrace          : yes
   - mem_usage         : yes
   - osc               : yes
   - ssl               : yes
   - tls               : yes
   - posix-time2       : yes
   - windows service   : no (requires winsvc)
   - YAML support      : yes
   - XML playlists     : yes

 * Monitoring
   - Prometheus        : yes

Installation method

From official packages in the release artifacts

Additional Info

Tested with StereoTool 10.41

[hansvanzutphen]

Hi, Stereo Tool developer here. This is most likely a rights issue. We try to save in $HOME/.st_plugin.presets (with st_plugin the name of the plugin without the .so at the end). Depending on where and under which user account you're running things, it could be that that location isn't writable.

To test if this is indeed the issue (and as a temporary workaround): Make your home directory writable for anything (chmod 777), then check if such a directory is created. (You may need to restart Stereo Tool for that). Don't forget to restore the original rights after this.

[rmens]

root@liqtest:~# getent passwd liquidsoap
liquidsoap:x:102:109::/usr/share/liquidsoap:/usr/sbin/nologin

So the Liquidsoap user that's created by the .deb package gets /usr/share/liquidsoap/ as home directory. It's owned by root and not by the user liquidsoap. So StereoTool, which runs as the user liquidsoap can't write to it. Chmod 777 works but isn't a secure option.

This is interesting because according to:

liquidsoap/.github/debian/postinst

Line 25 in 4dc4d24

--home /var/cache/liquidsoap --ingroup liquidsoap liquidsoap &&

the homedir is /var/cache/liquidsoap but that never gets created.

[rmens]

Creating the .liquidsoap.presets directory by hand in the homedir looks like the best hotfix and makes it work. I would still consider this a bug in Liquidsoap tho.

root@liqtest:/usr/share/liquidsoap# ls -la
total 20
drwxr-xr-x  5 root       root       4096 Oct 10 23:29 .
drwxr-xr-x 99 root       root       4096 Oct 10 23:29 ..
drwxr-xr-x  6 root       root       4096 Oct 10 23:29 camomile
drwxr-xr-x  3 root       root       4096 Oct 10 23:29 libs
drwxr-sr-x  2 liquidsoap liquidsoap 4096 Oct 10 23:31 .liquidsoap.presets

For the record: the directory always seems to be .liquidsoap.presets not the name of the .so file @hansvanzutphen.

[hansvanzutphen]

Oh. I guess our Linux code has a bug due to which it gets the name of the host application instead of its own name... I'll put that on our todo list. But that doesn't affect the issue itself.

[rmens]

My hotfix keeps expanding. Due to the non-writeable homedir of Liquidsoap it was necessary to create and chown the following directories:

/usr/share/liquidsoap/.liquidsoap.presets/
/usr/share/liquidsoap/.liquidsoap.log/

And the following file to get ST to save it's settings.

/usr/share/liquidsoap/.liquidsoap.rc

I defined preset="/etc/liquidsoap/st.ini" in my original .liq file, since settings should be stored in /etc/ in Linux and /usr/share is for read-only files.

I expected StereoTool to save its settings in the settings file that is specified in the preset= argument in Liquidsoap. It seems to ignore that and write to $HOME/$HOSTNAMEAPP.rc anyway.

This all is a bit of a mess. There's no point in defining a preset in the .liq configuration if ST has a hardcoded path for it. The preset= argument could be removed from Liquidsoap in that case since it's not very useful. Or the other way around: ST could respect the preset= argument and save it's settings to the defined file.

[toots]

I think that, in general, it's not reasonable to assume that all users have a $HOME directory and/or a writable one. System users, typically like with the liquidsoap user created by the debian package, are usually setup to have minimal access to the system.

It would be nice if the autosave feature could have a more flexible way to set the destination than relying on the presence of the home directory.

[rmens]

With 2.3.0 things seem to have changed. The homedir for the liquidsoap user is no longer /usr/share/liquidsoap/ owned by root, but /var/cache/liquidsoap/ owned by liquidsoap. Which allows StereoTool to read and write presets.

In the current StereoTool release there's still the problem with the name of the host application being used. But according to @hansvanzutphen that would be fixed in the next release.

It's still challenging to sync presets with volumes in docker containers. Because when mounting the directories and files StereoTool saves to in the container to the local server they get owned by root again.

[vitoyucepi]

Hi @rmens,
The container volumes usually preserve ownership and rights inside and outside the container. There may be some exceptions, such as NFS.
So chown and chmod the directory at the start of the container and everything should be fine.