On 11/22/2017 02:09 AM, Takashi Sakamoto wrote:
In my opinion, this patch is preferable, however it can always generate superfluous error messages when handling hook configuration on 'alsa.conf'. For example:
$ LD_PRELOAD=./src/.libs/libasound.so.2.0.0 amixer ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory ALSA lib dlmisc.c:85:(snd_dlopen) snd_dlopen: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: /usr/lib/x86_64-linux-gnu/alsa-lib//./src/.libs/libasound.so.2.0.0: cannot open shared object file: No such file or directory Simple mixer control 'IEC958',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] ...
When any hook configuration includes no lines with 'lib', 'snd_dlopen()' gets NULL as its first argument, then 'dlopen()' gets an inexistent path as its first argument, like:
Ah, this is a problem. But I struggled with the "alsaeq plugin" which, under ubuntu 17 something is not linked against libasound and when pulseaudio is configured to use it, it fails without saying anything useful and the hacker (me) has to spend too much time because ALSA does not use dlerror.
(parsing alsa.conf) snd_config_hooks_call() ->snd_dlopen(name = NULL) if (name == NULL) name = self filename = ALSA_PLUGIN_DIR + '/' + name dlopen(filename) (generate the error messages)
I don't know why alsa-lib is programmed as what it is, so have no idea to suggest better solution...
Additionally, your patch includes some issues of patch format:
- Not only your signature but also patch comment is required. The first
line is interpreted as patch title, and the rest is as comment.
okay, next time I'll write some text.
- Patches should be compliant to git-patch format. I encountered failure
of 'git am' for this patch. Please use 'git format-patch' command to generate patches for posting.
I used format-patch and imap-send. Maybe this bloated thunderbird did mess up (I configured it as explained in the man pages).
Anyway, do what you want with the patch above, I don't really care actually. Problem is solved on my side. I've seen messages in the wild from people with the same problem, I thought I could help a bit. I didn't see the "big picture" (that is: bad design of too many software).
All I know is that it's good practice to report errors to users. If a code path can "legitimately" generate errors, then the programmer needs to deal with it in a convenient way.
But yeah, I don't care. ALSA lib is bloated to start with. (This email is my last, I won't troll more, promise.)
When posting patches, please take care of the above.
Regards
Takashi Sakamoto