musl-libc on Linux works with Alpine Linux and FPC 3.2.2 but not 3.3.1

[Bogen85]

This is somewhat related to this: https://forum.lazarus.freepascal.org/index.php/topic,63680.msg

I filed an issue on this here: https://gitlab.com/freepascal.org/fpc/source/-/issues/40437

FPC 3.2.2 on alpine will compile and link dynamically linked executables that work as expected.

Code: Pascal  [Select][+][-]

1. {$mode objfpc}
2. {$h+}
3. {$codepage utf8}
4.  
5. program hello_libc;
6.  
7. uses ctypes;
8.  
9. function c_write (const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external 'libc' name 'write';
10.  
11. var
12.         s: string = 'hello ';
13. begin
14.         c_write(1, pchar(s), length(s));
15.         writeln('alpine musl!');
16. end.
17.  

Code: Text  [Select][+][-]

1. $ fpc hello_libc.pas
2. Free Pascal Compiler version 3.2.2 [2022/08/07] for x86_64
3. Copyright (c) 1993-2021 by Florian Klaempfl and others
4. Target OS: Linux for x86-64
5. Compiling hello_libc.pas
6. Linking hello_libc
7. Warning: "crtbegin.o" not found, this will probably cause a linking failure
8. Warning: "crtend.o" not found, this will probably cause a linking failure
9. 16 lines compiled, 0.0 sec
10. 2 warning(s) issued
11.  
12. $ file hello_libc
13. hello_libc: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-x86_64.so.1, for GNU/Linux 2.4.0, stripped
14.  
15. $ ldd hello_libc
16. /lib/ld-musl-x86_64.so.1 (0x7ff02d918000)
17. libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7ff02d918000)
18.  
19. $ ./hello_libc
20. hello alpine musl!
21.  

So it works on 3.2.2, but not on 3.3.1, causing the build of FPC 3.3.1 on Alpine Linux to fail (hence the issue report I filed).

[Bogen85]

I filed an issue on this here: https://gitlab.com/freepascal.org/fpc/source/-/issues/40437

FPC 3.2.2 on alpine will compile and link dynamically linked executables that work as expected.

For 3.3.1 it turned out to be shared object pathing issue.

So it works on 3.2.2, but not on 3.3.1, causing the build of FPC 3.3.1 on Alpine Linux to fail (hence the issue report I filed).

I'll work on proper patch for it, but for now I can use both FPC 3.2.2 and the latest FPC 3.3.1 on Alpine Linux with musl libc.

[Joanna from IRC]

Congrats 

[toby]

i have installed musl into /projects/musl/usr.local.musl
with the
/projects/musl > ls usr.local.musl/
bin  include  lib

/projects/musl > ls usr.local.musl/lib
crt1.o  crtn.o  libcrypt.a  libdl.a  libpthread.a  librt.a    libxnet.a       rcrt1.o
crti.o  libc.a  libc.so     libm.a   libresolv.a   libutil.a  musl-gcc.specs  Scrt1.o

---

i have musl static and libc static working with linklib and libc dynamic working with function external lib

but none of the function 'external lib'  work for musl
but none of musl dynamic work  either with function 'external lib' or linklib work

could you look at the code and tell me what i am doing wrong?

Code: Pascal  [Select][+][-]

1. program musl; // from https://forum.lazarus.freepascal.org/index.php/topic,64570.0.html
2.  
3. uses ctypes;
4.  
5. var s : ansistring = 'write : ';
6.  
7. // glibc dynamic linked  good
8. //function c_write(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external 'libc' name 'write';
9.  
10. // glibc static linked
11. {$linklib /lib/libc.a} // good
12. function c_write(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';
13.  
14. // glibc dynamic linked
15. //{$linklib /lib/libc.so} // fails
16. //{$linklib libc} // good
17. //function c_write(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';
18.  
19.  
20. // musl static linked
21. {$linklib /projects/musl/usr.local.musl/lib/libc.a} // good
22. function c_write1(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';
23.  
24. // musl dynamic linked
25. //{$linklib /projects/musl/usr.local.musl/lib/libc.so} // fails
26. //function c_write1(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';
27.  
28. // /usr/local/bin/ld: cannot find -l/projects/musl/usr.local.musl/lib/libc.a
29. //function c_write2(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external '/projects/musl/usr.local.musl/lib/libc.a' name 'write';
30.  
31. // /usr/local/bin/ld: cannot find -l/projects/musl/usr.local.musl/lib/libc
32. //function c_write2(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external '/projects/musl/usr.local.musl/lib/libc.so' name 'write';
33.  
34.  
35. begin
36.  
37. writeln;
38.  
39. // glibc
40. c_write(1, pchar(s), length(s));
41. writeln('libc');
42.  
43. // musl
44. c_write1(1, pchar(s), length(s));
45. writeln('musl1');
46.  
47.  
48. // external musl method static and dynamic both fail
49. //c_write2(1, pchar(s), length(s));
50. //writeln('musli2');
51.  
52. writeln;
53.  
54. end.
55.  

[Bogen85]

could you look at the code and tell me what i am doing wrong?

What compiler are you using?
No official compiler for FPC supports musl-libc.
There is a hack on the alpine package for fpc to make it work on alpine.

I have a patch for x86_64 mainline FPC and musl libc, but I need to do some more work on it to make it work for the other architectures and build a compiler for it when other libc are present.

https://gitlab.com/bogen85/source/-/compare/main...main?from_project_id=28644964#81870c36041af85b22d9720de972572a2d733365

But there is a bit more work to do on it: https://gitlab.com/freepascal.org/fpc/source/-/issues/40437

[toby]

What compiler are you using?
fpc-3.3.1

No official compiler for FPC supports musl-libc.
i'm pretty sure the static musl one works with fpc

// musl static linked
{$linklib /projects/musl/usr.local.musl/lib/libc.a} // good
function c_write1(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';
// musl
c_write1(1, pchar(s), length(s));
writeln('musl1');

----




i'm having trouble getting it to use the dynamic library with the same linklib code
// musl dynamic linked
//{$linklib /projects/musl/usr.local.musl/lib/libc.so} // fails
//function c_write1(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external name 'write';

or using  extenal fullpath with both musl static or dynamic
// /usr/local/bin/ld: cannot find -l/projects/musl/usr.local.musl/lib/libc.a
//function c_write2(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external '/projects/musl/usr.local.musl/lib/libc.a' name 'write';

// /usr/local/bin/ld: cannot find -l/projects/musl/usr.local.musl/lib/libc
//function c_write2(const fd: cint; const buffer: pchar; const count: cint): cint; cdecl; external '/projects/musl/usr.local.musl/lib/libc.so' name 'write';