Running Linux apps compiled and linked against musl

[wkozaczuk]

I think there are many apps these days built to run on Alpine Linux that uses musl instead of glibc.

Given that OSv uses musl and extends it to expose as a subset of glibc, how difficult would it be to expose musl as-is at the same time and thus support musl-built Linux binaries? Is it even possible?

[wkozaczuk]

Recently I have played trying to build and test some app images on OSv using alpine linux which uses musl instead of glibc. I have successfully tried busybox, lighttpd and nodejs. Both worked fine. I have pushed the commit 287c379 that officially exposes OSv libc as musl.

Lighttpd required adding this missing symbol explicit_bzero (see the commit e5515cf) which makes me think that maybe some executables use some sort of glibc-compatibility layer. But ldd does not show it:

/ # ldd /usr/sbin/lighttpd
	/lib/ld-musl-x86_64.so.1 (0x7f658931c000)
	libpcre.so.1 => /usr/lib/libpcre.so.1 (0x7f658927c000)
	libcrypto.so.1.1 => /lib/libcrypto.so.1.1 (0x7f6589000000)
	libfam.so.0 => /usr/lib/libfam.so.0 (0x7f6588ff7000)
	libev.so.4 => /usr/lib/libev.so.4 (0x7f6588fe9000)
	libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f658931c000)
/ # ldd /bin/busybox 
	/lib/ld-musl-x86_64.so.1 (0x7f8cc7076000)
	libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f8cc7076000)
/ # ldd /usr/bin/node 
	/lib/ld-musl-x86_64.so.1 (0x7f7735235000)
	libz.so.1 => /lib/libz.so.1 (0x7f773363a000)
	libuv.so.1 => /usr/lib/libuv.so.1 (0x7f7733610000)
	libcares.so.2 => /usr/lib/libcares.so.2 (0x7f77335fe000)
	libnghttp2.so.14 => /usr/lib/libnghttp2.so.14 (0x7f77335d9000)
	libcrypto.so.1.1 => /lib/libcrypto.so.1.1 (0x7f773335d000)
	libssl.so.1.1 => /lib/libssl.so.1.1 (0x7f77332dd000)
	libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x7f7733144000)
	libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x7f7733130000)
	libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f7735235000)

In either case, I think we might close this issue.