How to make ALSA relocatable in the filesystem?

[probonopd]

We want to bundle a private copy of ALSA with our application, so that the ALSA from the Linux distribution is not used at all. Yet it seems ALSA is relying on some absolute paths compiled in with no clear way to pass in a different location for ALSA at runtime.

How to do this?

Use case:
As an application developer, I want to ship my application together with all dependencies. This bundle is using musl libc, ships its own musl libc and runtime, and it is intended to also run on glibc-based systems.

Reference:
mumble-voip/mumble#3959 (comment)

[probonopd]

It appears that https://github.com/flatpak/freedesktop-sdk-images/blob/1.6/alsa-lib-plugin-path.patch might be addressing this?

[perexg]

Commited to master.

[bkuhls]

This patch breaks building alsa-lib with uClibc:

dlmisc.c:79:51: error: ‘RTLD_DL_LINKMAP’ undeclared (first use in this function)
   if (dladdr1(&snd_dlpath, &info, (void**)&links, RTLD_DL_LINKMAP) == 0)
dlmisc.c:81:38: error: ‘RTLD_DI_ORIGIN’ undeclared (first use in this function)
   if (links != NULL && dlinfo(links, RTLD_DI_ORIGIN, origin) == 0) {

RTLD_DL_LINKMAP & RTLD_DI_ORIGIN, are unsupported on uClibc:
https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/include/dlfcn.h#n106

[perexg]

This patch breaks building alsa-lib with uClibc:

dlmisc.c:79:51: error: ‘RTLD_DL_LINKMAP’ undeclared (first use in this function)
   if (dladdr1(&snd_dlpath, &info, (void**)&links, RTLD_DL_LINKMAP) == 0)
dlmisc.c:81:38: error: ‘RTLD_DI_ORIGIN’ undeclared (first use in this function)
   if (links != NULL && dlinfo(links, RTLD_DI_ORIGIN, origin) == 0) {

RTLD_DL_LINKMAP & RTLD_DI_ORIGIN, are unsupported on uClibc:
https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/include/dlfcn.h#n106

Why uclibc build defines __GLIBC__ ?

alsa-lib/src/dlmisc.c

Line 72 in 6eb78d4

#ifdef __GLIBC__

If you have a better way to check non-glibc build, we can change it.