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feat: Add spotify-on-musl

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ptrcnull 2021-11-19 16:22:29 +01:00
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---
title: "WIP: Running Spotify on musl"
date: 2021-11-19T16:22:02+01:00
draft: false
---
Note: this post is not finished yet (and might never be) - it's more of a collection of notes.
When trying to run Spotify on Alpine, most answers on the internet pointed to [Flatpak](https://flatpak.org/).
And don't get me wrong - Flatpak is great and allows for running glibc-based apps
with minimal setup, but... I'd really like to get Spotify to run natively, mostly because containers a bit heavier in terms of disk space and interoperability is .
Let's start by downloading Spotify's deb package from [the official repository](https://repository-origin.spotify.com/pool/non-free/s/spotify-client/) and unpacking it into downloads.
Most of the files are in `usr/share/spotify`, so we'll try to just go there and run it.
```
$ cd usr/share/spotify
$ ./spotify
zsh: no such file or directory: ./spotify
```
Oh right, it's missing some stuff. What stuff though?
```
$ ldd spotify
(114 lines skipped...)
Error relocating ./libcef.so: __libc_realloc: symbol not found
Error relocating ./libcef.so: __libc_free: symbol not found
Error relocating ./libcef.so: __fdelt_chk: symbol not found
Error relocating ./libcef.so: __fprintf_chk: symbol not found
Error relocating ./libcef.so: __sprintf_chk: symbol not found
Error relocating ./libcef.so: initstate_r: symbol not found
Error relocating ./libcef.so: random_r: symbol not found
Error relocating ./libcef.so: gnu_get_libc_version: symbol not found
Error relocating ./libcef.so: __register_atfork: symbol not found
Error relocating ./libcef.so: __longjmp_chk: symbol not found
Error relocating ./libcef.so: __libc_stack_end: symbol not found
Error relocating ./spotify: strtoll_l: symbol not found
Error relocating ./spotify: strtoull_l: symbol not found
Error relocating ./spotify: __isnanf: symbol not found
Error relocating ./spotify: __isinff: symbol not found
Error relocating ./spotify: __isnan: symbol not found
Error relocating ./spotify: __isinf: symbol not found
Error relocating ./spotify: __cxa_thread_atexit_impl: symbol not found
```
It seems that it uses a lot of glibc-specific stuff, but we can use Adelie Linux's [gcompat](https://git.adelielinux.org/adelie/gcompat) to make it work.
```
$ apk add gcompat
(1/3) Installing musl-obstack (1.2.2-r0)
(2/3) Installing libucontext (1.1-r0)
(3/3) Installing gcompat (1.0.0-r2)
OK: 11425 MiB in 1571 packages
$ patchelf --set-interpreter /lib/ld-musl-x86_64.so.1 spotify
$ patchelf --add-needed libgcompat.so.0 spotify
$ ldd spotify
(97 lines skipped...)
Error relocating ./libcef.so: __mbrlen: symbol not found
Error relocating ./libcef.so: __close: symbol not found
Error relocating ./libcef.so: initstate_r: symbol not found
Error relocating ./libcef.so: random_r: symbol not found
```
That's much better, but there are still a few things missing. `random_r` was added
[a few months ago](https://git.adelielinux.org/adelie/gcompat/-/commit/59e99e9e6db4fd4d33786fbe3ffd3fabf4a49dd7),
but `__mbrlen` and `__close` were still missing, so I cloned gcompat and [added them in](https://github.com/ptrcnull/gcompat).
Note: gcompat seems to be temporarily no longer maintained as A. Wilcox has [retired](https://catfox.life/2020/10/21/leaving-the-linux-distribution-community/),
so I pushed my changed to a fork on GitHub instead of creating a merge request to the original repo.
After recompiling gcompat and trying to run Spotify again, it still complains about missing glibc:
```
$ ./spotify
Error loading shared library ld-linux-x86-64.so.2: No such file or directory (needed by libcef.so)
```
Fortunately, another `patchelf`, this time to `libcef.so`, makes the error go away:
```
$ patchelf --remove-needed ld-linux-x86-64.so.2 libcef.so
$ ./spotify
```
Aaand... it crashes with `boost::filesystem::read_symlink: No such file or directory: "/proc/self/exe"`.
That's weird, `/proc/self/exe` should be present, `read_symlink` just calls
[https://github.com/steinwurf/boost/blob/1c73b071b4c458de71923072be2a7ee8e4c87799/libs/filesystem/src/operations.cpp#L1586](readlink),
and `readlink` [uses the syscall](https://github.com/bminor/musl/blob/cfdfd5ea3ce14c6abf7fb22a531f3d99518b5a1b/src/unistd/readlink.c#L5), right?
Nope, gcompat [replaces](https://git.adelielinux.org/adelie/gcompat/-/blob/current/libgcompat/readlink.c) readlink with its own function to intercept `/proc/self/exe` (ugh),
but as we don't use the loader, we can remove it from the Makefile and build again.
Another recompile of gcompat later, maybe now it would launch?
```
$ ./spotify
[1] 26559 segmentation fault (core dumped) ./spotify
```
Whoops, it doesn't look good...
After running `gdb spotify core`, it looks like it [segfaults](https://git.adelielinux.org/adelie/gcompat/-/issues/344) in `savestate_r () from /lib/libgcompat.so.0`.
We could try to fix this _or_ we can replace it with a [fair dice roll](https://xkcd.com/221/):
```diff
diff --git a/libgcompat/random_r.c b/libgcompat/random_r.c
index 5bc7053..f6e7071 100644
--- a/libgcompat/random_r.c
+++ b/libgcompat/random_r.c
@@ -141,4 +141,7 @@ int random_r(struct random_data *restrict buf, int32_t *restrict result) {
}
+ *result = 4;
+ return 0;
+
if (buf->n == 0) {
k = buf->x[0] = lcg31(buf->x[0]);
```
(and also add `return 0;` before first `savestate_r` in `initstate_r`)
Aaand... it shows a window!
![Empty white window on gray background, with title Spotify](/posts/spotify-on-musl/white_window.png)
Sadly, after a while, the enthusiasm goes away - the window stays white and doesn't display any content.
Command line argument `--show-console` doesn't give us any helpful info either:
```
$ ./spotify --show-console
14:54:32.302 I [f:156 ] Access allowance changed from online: 0 stream: 0, sync: 0, persistent conn: 0 to online: 1 stream: 1, sync: 0, persistent conn: 1
14:54:32.334 I [f:77 ] Connectivity policy is initially allow_all
14:54:32.334 I [f:79 ] Connection type is initially unknown
14:54:32.334 I [f:96 ] Enabling all persistent connections
14:54:32.353 I [f:150 ] D-Bus name 'org.freedesktop.NetworkManager' does not exist on system bus
```
Okay, but A. Wilcox [has the same issue](https://catfox.life/2020/07/06/live-from-adelie-streaming-spotify-on-musl/) - maybe we can use that?
```
$ ldd spotify
/lib/ld-musl-x86_64.so.1 (0x7f0b5dbf5000)
libgcompat.so.0 => /lib/libgcompat.so.0 (0x7f0b5dbe1000)
libm.so.6 => /lib/ld-musl-x86_64.so.1 (0x7f0b5dbf5000)
libdl.so.2 => /lib/ld-musl-x86_64.so.1 (0x7f0b5dbf5000)
libasound.so.2 => /usr/lib/libasound.so.2 (0x7f0b5daf6000)
libatomic.so.1 => /usr/lib/libatomic.so.1 (0x7f0b5daed000)
libcurl-gnutls.so.4 => /usr/lib/libcurl-gnutls.so.4 (0x7f0b5da73000)
libcef.so => ./libcef.so (0x7f0b52887000)
(86 lines skipped...)
```
It seems to match (libm/libdl before libcef), so let's try removing them and see what happens:
```
$ patchelf --remove-needed libm.so.6 libcef.so
$ patchelf --remove-needed libdl.so.2 libcef.so
$ ./spotify --show-console
15:02:04.445 I [f:156 ] Access allowance changed from online: 0 stream: 0, sync: 0, persistent conn: 0 to online: 1 stream: 1, sync: 0, persistent conn: 1
15:02:04.491 I [f:77 ] Connectivity policy is initially allow_all
15:02:04.491 I [f:79 ] Connection type is initially unknown
15:02:04.492 I [f:96 ] Enabling all persistent connections
15:02:04.500 I [f:150 ] D-Bus name 'org.freedesktop.NetworkManager' does not exist on system bus
```
Unfortunately, it still shows the white window and `strace` reveals that it still segfaults:
```
28567 +++ killed by SIGSEGV (core dumped) +++
28566 +++ killed by SIGSEGV (core dumped) +++
28565 +++ killed by SIGSEGV (core dumped) +++
28564 +++ killed by SIGSEGV (core dumped) +++
28563 +++ killed by SIGSEGV (core dumped) +++
```
This is where the post ends, at least for now (2021-11-19).
If you manage to make it further than I did, please DM me on [Telegram](https://t.me/ptrcnull) or send an [e-mail](mailto:hello@ptrcnull.me).

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