How to compile a 32-bit alpine greeting world?

Question

Given the simple hello world code:

#include <stdio.h>
int main(void){
  puts("hello");
  return 0;
}

In a 64-bit alpine Linux installation, I tried to compile it both 64-bit and 32-bit. The first works fine, but the second is missing 32-bit libraries:

~ # gcc -Wall hello.c 
~ # gcc -Wall -m32 hello.c 
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libssp_nonshared.a when searching for -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libssp_nonshared.a when searching for -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libc.so when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libc.a when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libc.so when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libc.a when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status

Since I did not find an obvious way to fix this, I extracted the 32-bit version of gcc, libgcc and musl-dev, extracted to the local directory and set LIBRARY_PATH:

~ # LIBRARY_PATH=usr/lib/gcc/i586-alpine-linux-musl/5.3.0:usr/lib gcc -Wall -m32 hello.c 
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/crtbeginS.o' is incompatible with i386 output
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/crtendS.o' is incompatible with i386 output
collect2: error: ld returned 1 exit status
~ # 

This partially fixes the problems, but gcc still tries to use 64-bit libraries first and finds attempts to find files with 64-bit crt.

So, what is the correct way to compile a 32-bit binary in alpine Linux?

---

To make the last problem clearer, look at this:

~ # LIBRARY_PATH=/tmp gcc --verbose -Wall -m32 hello.c 2>&1|grep LIBRARY_PATH
LIBRARY_PATH=/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/:/tmp/:/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/lib/:/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../:/lib/:/usr/lib/

LIBRARY_PATH, . "" , 64- . crt , , .

( , ), , , gcc.

Answer 1

gcc -v alpine gcc multilib:

--disable-multilib

multilib debian:

--with-multilib-list=m32,m64,mx32 --enable-multilib

-m32 Multilib . 32- .