Making world from scratch with this change applied results in

===> lib/virtual_oss/null (install)
install -U  -s -o root -g wheel -m 444  -C -S  voss_null.so /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/virtual_oss/
install: /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/virtual_oss: No such file or directory
*** [_libinstall] Error code 71

for me.

For now I just fooled the buildsystem by creating those dirs manually.

All right, figured the installation problem. The following diff should be added to the review:

diff --git a/etc/mtree/BSD.lib32.dist b/etc/mtree/BSD.lib32.dist
index a736a7d58b66..8a3fe9a34714 100644
--- a/etc/mtree/BSD.lib32.dist
+++ b/etc/mtree/BSD.lib32.dist
@@ -21,5 +21,7 @@
         ..
         pkgconfig
         ..
+        virtual_oss
+        ..
     ..
 ..
diff --git a/etc/mtree/BSD.usr.dist b/etc/mtree/BSD.usr.dist
index 7d3a72f43fa1..265f4cfe8753 100644
--- a/etc/mtree/BSD.usr.dist
+++ b/etc/mtree/BSD.usr.dist
@@ -101,6 +101,8 @@
         ..
         ossl-modules
         ..
+        virtual_oss
+        ..
     ..
     libdata
         ldscripts

In D52308#1198586, @arrowd wrote:

All right, figured the installation problem. The following diff should be added to the review:

diff --git a/etc/mtree/BSD.lib32.dist b/etc/mtree/BSD.lib32.dist
index a736a7d58b66..8a3fe9a34714 100644
--- a/etc/mtree/BSD.lib32.dist
+++ b/etc/mtree/BSD.lib32.dist
@@ -21,5 +21,7 @@
         ..
         pkgconfig
         ..
+        virtual_oss
+        ..
     ..
 ..
diff --git a/etc/mtree/BSD.usr.dist b/etc/mtree/BSD.usr.dist
index 7d3a72f43fa1..265f4cfe8753 100644
--- a/etc/mtree/BSD.usr.dist
+++ b/etc/mtree/BSD.usr.dist
@@ -101,6 +101,8 @@
         ..
         ossl-modules
         ..
+        virtual_oss
+        ..
     ..
     libdata
         ldscripts

Good catch! I always forget about those... Thanks for the valuable help. :-)

Most issues have been addressed. Only ones remaining so far:

• virtual_oss_wait() is needed by some backends, but for now we get an error because this symbol is defined by virtual_oss(8), so the shared libs cannot use it. Defining it in the library code is also not easily possible, as virtual_oss_wait() uses variables from virtual_oss(8) (voss_dsp_samples and voss_dsp_sample_rate)
• rc script inline comments (see below).

The patch is essentially finalized and IMHO ready to commit. Only thing remaining (but not really that important) are the rc script inline comments.

Also, since I'd like this to land in 15.0, I guess we'd need to bump __FreeBSD_version for stable/15, so that ports like D52593 can build only if the machine does have virtual_oss in base (related discussion there). @markj @emaste @cperciva What do you think?

In D52308#1201895, @christos wrote:

The patch is essentially finalized and IMHO ready to commit. Only thing remaining (but not really that important) are the rc script inline comments.

Also, since I'd like this to land in 15.0, I guess we'd need to bump __FreeBSD_version for stable/15, so that ports like D52593 can build only if the machine does have virtual_oss in base (related discussion there). @markj @emaste @cperciva What do you think?

Yes, go ahead with the __FreeBSD_version bump. But please get it done soon; I'll be creating releng/15.0 in 1.5 weeks and this probably can't go in after that point.

In D52308#1203289, @cperciva wrote:

In D52308#1201895, @christos wrote:

The patch is essentially finalized and IMHO ready to commit. Only thing remaining (but not really that important) are the rc script inline comments.

Also, since I'd like this to land in 15.0, I guess we'd need to bump __FreeBSD_version for stable/15, so that ports like D52593 can build only if the machine does have virtual_oss in base (related discussion there). @markj @emaste @cperciva What do you think?

Yes, go ahead with the __FreeBSD_version bump. But please get it done soon; I'll be creating releng/15.0 in 1.5 weeks and this probably can't go in after that point.

The patch is done on my side, once it's reviewed I will push it immediately.

I took a look at the rc script and I've got some suggestions.

I'm still getting

===> lib/virtual_oss (all)
===> lib/virtual_oss/null (all)
make[6]: /usr/obj/usr/src/amd64.amd64/lib/virtual_oss/null/.depend:1: ignoring stale .depend for /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libprivatesamplerate.a
Building shared library voss_null.so
cc -target x86_64-unknown-freebsd16.0 --sysroot=/usr/obj/usr/src/amd64.amd64/tmp -B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin  -Wl,-zrelro    -fstack-protector-strong -shared -Wl,-x -Wl,--fatal-warnings -Wl,--warn-shared-textrel  -o voss_null.so.full -Wl,-soname,voss_null.so null.pico  -lprivatesamplerate 
ld: error: unable to find library -lprivatesamplerate

when trying to build this diff. It also does not apply with arc patch for me for some reason.

In D52308#1204955, @arrowd wrote:

I'm still getting

===> lib/virtual_oss (all)
===> lib/virtual_oss/null (all)
make[6]: /usr/obj/usr/src/amd64.amd64/lib/virtual_oss/null/.depend:1: ignoring stale .depend for /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libprivatesamplerate.a
Building shared library voss_null.so
cc -target x86_64-unknown-freebsd16.0 --sysroot=/usr/obj/usr/src/amd64.amd64/tmp -B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin  -Wl,-zrelro    -fstack-protector-strong -shared -Wl,-x -Wl,--fatal-warnings -Wl,--warn-shared-textrel  -o voss_null.so.full -Wl,-soname,voss_null.so null.pico  -lprivatesamplerate 
ld: error: unable to find library -lprivatesamplerate

when trying to build this diff. It also does not apply with arc patch for me for some reason.

Does @emaste 's suggestion in the inline comment fix this?

ld: error: unable to find library -lprivatesamplerate

Does @emaste 's suggestion in the inline comment fix this?

My comment is related to this, but I'm still getting this as well, looking..

In D52308#1205072, @emaste wrote:

ld: error: unable to find library -lprivatesamplerate

Does @emaste 's suggestion in the inline comment fix this?

My comment is related to this, but I'm still getting this as well, looking..

Interesting, I cannot reproduce this for some reason...

Something like the patch below (applied to each virtual_oss subdir) works. It's gross, but we're already doing this in e.g. lib/googletest/gmock/Makefile

diff --git a/lib/virtual_oss/bt/Makefile b/lib/virtual_oss/bt/Makefile
index 15413b7a1f1e..3d075946f362 100644
--- a/lib/virtual_oss/bt/Makefile
+++ b/lib/virtual_oss/bt/Makefile
@@ -9,6 +9,7 @@ CFLAGS+=        -I${SRCTOP}/usr.sbin/virtual_oss/virtual_oss \
                -I${SRCTOP}/contrib/libsamplerate
 LDFLAGS+=      -lbluetooth -lsdp
 LIBADD=                samplerate
+LDFLAGS+=      -L${.OBJDIR:H:H}/libsamplerate
 
 .if defined(HAVE_LIBAV)
 CFLAGS+=       -I${LOCALBASE:U/usr/local}/include -DHAVE_LIBAV

In D52308#1205084, @emaste wrote:

Something like the patch below (applied to each virtual_oss subdir) works. It's gross, but we're already doing this in e.g. lib/googletest/gmock/Makefile

virtual_oss/Makefile.inc, please

diff --git a/lib/virtual_oss/bt/Makefile b/lib/virtual_oss/bt/Makefile
index 15413b7a1f1e..3d075946f362 100644
--- a/lib/virtual_oss/bt/Makefile
+++ b/lib/virtual_oss/bt/Makefile
@@ -9,6 +9,7 @@ CFLAGS+=        -I${SRCTOP}/usr.sbin/virtual_oss/virtual_oss \
                -I${SRCTOP}/contrib/libsamplerate
 LDFLAGS+=      -lbluetooth -lsdp
 LIBADD=                samplerate
+LDFLAGS+=      -L${.OBJDIR:H:H}/libsamplerate
 
 .if defined(HAVE_LIBAV)
 CFLAGS+=       -I${LOCALBASE:U/usr/local}/include -DHAVE_LIBAV

In D52308#1205129, @kevans wrote:

In D52308#1205084, @emaste wrote:

Something like the patch below (applied to each virtual_oss subdir) works. It's gross, but we're already doing this in e.g. lib/googletest/gmock/Makefile

virtual_oss/Makefile.inc, please

I'm thinking more this is a demonstration of the issue and we need to find a way to do this properly for virtual_oss (and convert googletest as well) rather than a cleaner version of the hack.

If it builds fine and there are no further issues I think we can commit it.

LDFLAGS+= -L in lib/:

lib/atf/libatf-c++/Makefile:LDFLAGS+=   -L${.OBJDIR:H}/libatf-c
lib/csu/tests/dynamiclib/Makefile:LDFLAGS+=     -Wl,-rpath,${TESTSDIR} -L${.OBJDIR:H}/dso
lib/googletest/gmock/Makefile:LDFLAGS+= -L${.OBJDIR:H}/gtest
lib/googletest/gmock_main/Makefile:LDFLAGS+=    -L${LIBGTESTDIR}
lib/googletest/gmock_main/Makefile:LDFLAGS+=    -L${LIBGMOCKDIR}
lib/googletest/gtest_main/Makefile:LDFLAGS+=    -L${LIBGTESTDIR}
lib/libc/tests/stdlib/Makefile:LDFLAGS.$t+=     -L${LIBNETBSD_OBJDIR}
lib/libc/tests/tls/Makefile:LDFLAGS.tls_dynamic_test+=  -Wl,-rpath,${TESTSDIR} -L${DSODIR}
lib/libthr/tests/dlopen/Makefile:LDFLAGS+=      -L${.OBJDIR}/dso -Wl,-rpath=${TESTDIR}
lib/libxo/encoder/csv/Makefile:LDFLAGS += -L${.OBJDIR:H:H}/libxo

So I think it's fine to use the same -L hack here, and putting it in virtual_oss/Makefile.inc at least avoid duplication.