Static linking of a custom glibc

Static linking of a custom glibc

[Mahmood Naderan]

Hi
I would like to statically link my program to a custom glibc version. As you can see below, the following commands are wrong.

$ gcc -c test.c && gcc -o test -Wl,--emit-relocs /opt/glibc-2.23-install/lib/libc.a test.o
/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/opt/glibc-2.23-install/lib/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie
collect2: error: ld returned 1 exit status


$ gcc -fPIE -c test.c && gcc -o test -pie -Wl,--emit-relocs /opt/glibc-2.23-install/lib/libc.a test.o
/usr/bin/ld: /opt/glibc-2.23-install/lib/libc.a(libc-start.o): relocation R_X86_64_32 against `_dl_starting_up' can not be used when making a shared object; recompile with -fPIC
/opt/glibc-2.23-install/lib/libc.a: error adding symbols: Bad value
collect2: error: ld returned 1 exit status


$ gcc -fPIC -c test.c && gcc -o test -pie -Wl,--emit-relocs /opt/glibc-2.23-install/lib/libc.a test.o
/usr/bin/ld: /opt/glibc-2.23-install/lib/libc.a(libc-start.o): relocation R_X86_64_32 against `_dl_starting_up' can not be used when making a shared object; recompile with -fPIC
/opt/glibc-2.23-install/lib/libc.a: error adding symbols: Bad value
collect2: error: ld returned 1 exit status



Regards,
Mahmood

Re: Static linking of a custom glibc

[Jim Wilson]

On Wed, Jun 3, 2020 at 5:44 AM Mahmood Naderan via Gcc-help
<gcc-help@gcc.gnu.org> wrote:
> I would like to statically link my program to a custom glibc version. As you can see below, the following commands are wrong.

This looks like more of a glibc question than a gcc question.  I would
suggest reading
   https://sourceware.org/glibc/wiki/Testing/Builds

Jim

Re: Static linking of a custom glibc

[Mahmood Naderan]

>This looks like more of a glibc question than a gcc question.  I would
>suggest reading
>  https://sourceware.org/glibc/wiki/Testing/Builds


Yes I am able to link to the new glibc with "-Wl,-rpath" and "-Wl,--dynamic-linker ".
But, even with the default libc on the system, I am not able to link statically.
$ gcc -o test -Wl,--emit-relocs -Wl,-Bstatic test.o              
/usr/bin/ld: cannot find -lgcc_s/usr/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status

I ask that on glibc list, but it seems that this is a gcc related problem.I am confused...

Regards,
Mahmood 
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Testing/Builds - glibc wiki


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Re: Static linking of a custom glibc

[Andrew Haley]

On 04/06/2020 06:17, Mahmood Naderan via Gcc-help wrote:
>> This looks like more of a glibc question than a gcc question.  I would
>> suggest reading
>>   https://sourceware.org/glibc/wiki/Testing/Builds
>
> Yes I am able to link to the new glibc with "-Wl,-rpath" and "-Wl,--dynamic-linker ".
> But, even with the default libc on the system, I am not able to link statically.
> $ gcc -o test -Wl,--emit-relocs -Wl,-Bstatic test.o
> /usr/bin/ld: cannot find -lgcc_s/usr/bin/ld: cannot find -lgcc_s
> collect2: error: ld returned 1 exit status
>
> I ask that on glibc list, but it seems that this is a gcc related problem.I am confused...

What is that command supposed to do? You're telling GCC to compile and
link dynamically dynamically, but telling the linker to link
statically. if you want GCC to link statically you're going to have to
use -static. You're also going to have to compile statically, with
-static.

If I want to link statically with a custom libc, I can do this:

gcc -static hello.c -Wl,--as-needed /usr/lib64/libc.a -Wl,--no-as-needed

Use the GCC option -Wl,-Map,mapfile and you'll be able to see what
happens.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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