Hi! I have a question regarding linking binaries under hurd.
I found that if I compile binaries to object files under linux and then
link it under hurd agains its libc everything works OK.
I'am trying to port a386 and Linux/a386 to hurd, so I'm compiling linux
kernel under linux and I would like to link it against hurd's a386 and
libc, but the problem is that I'm not using gcc but ld directly.
Normally If I compile sample program under linux to .o file I can then
link it against standard libraries doing something like this:
ld -Bstatic -m elf_i386 -e _start main.o /usr/lib/crt1.o /usr/lib/crti.o
/usr/lib/crtn.o /usr/lib/libc.a
/usr/lib/gcc-lib/i486-unknown-linux-gnulibc1/2.7.2.3/libgcc.a
-rpath /lib -Bstatic -o main
and it works well.
But if I do something similar under hurd:
ld -Bstatic -m elf_i386 -e _start /usr/lib/crtn.o main.o /usr/lib/crt0.o
/usr/lib/crti.o /lib/libc.a -o main -Bstatic
it segfaults in _init.
If I disassemble it, it looks:
0x80480b8 <_init>: push %ebp
0x80480b9 <_init+1>: mov %esp,%ebp
0x80480bb <_init+3>: sub $0x14,%esp
0x80480be <_init+6>: push %ebx
0x80480bf <_init+7>: call 0x80480c4 <_init+12>
0x80480c4 <_init+12>: pop %ebx
0x80480c5 <_init+13>: add $0x58bfc,%ebx
0x80480cb <_init+19>: cmpl $0x0,0xc(%ebx)
0x80480d2 <_init+26>: je 0x80480d9 <_init+33>
0x80480d4 <_init+28>: call 0x0
0x80480d9 <_init+33>: lea 0x0(%esi),%esi
0x80480dc: add %al,(%eax)
0x80480de: add %al,(%eax)
0x80480e0 <main>: push %ebp
0x80480e1 <main+1>: mov %esp,%ebp
(...)
that's all... it ends in _init+33...
But if I compile static binary using gcc it it longer:
0x80480b4 <_init>: push %ebp
0x80480b5 <_init+1>: mov %esp,%ebp
0x80480b7 <_init+3>: sub $0x14,%esp
0x80480ba <_init+6>: push %ebx
0x80480bb <_init+7>: call 0x80480c0 <_init+12>
0x80480c0 <_init+12>: pop %ebx
0x80480c1 <_init+13>: add $0x58d34,%ebx
0x80480c7 <_init+19>: cmpl $0x0,0xc(%ebx)
0x80480ce <_init+26>: je 0x80480d5 <_init+33>
0x80480d0 <_init+28>: call 0x0
0x80480d5 <_init+33>: lea 0x0(%esi),%esi
0x80480d8 <_init+36>: call 0x8048194 <frame_dummy>
0x80480dd <_init+41>: call 0x80924e0 <__do_global_ctors_aux>
0x80480e2 <_init+46>: pop %ebx
0x80480e3 <_init+47>: leave
0x80480e4 <_init+48>: ret
So my question is: HOW should I link binaries under hurd? :)
--
Mariusz Wołoszyn
Internet Security Specialist, Internet Partners, GTS Poland
