About 32bit binary on amd64

Hi all,

I want to compile 32bit binary on amd64, but I met with the problem.
Could you teach me the best solution, please?


My environment is FreeBSD 8.1-PRERELEASE #0: Tue May 18 12:01:26 JST 2010.

I compiled and executed test.c as below on amd64.

-- begin -- test.c ------------------------------------------------------
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>

int main()
{
	void *ptr;
	ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0);
	if (ptr == MAP_FAILED) {
		perror("mmap"); exit(1);
	}
	printf("%lx\n", (unsigned long)ptr);
	munmap(ptr, 4096);

	exit(0);
}
-- end -- test.c --------------------------------------------------------

% gcc -m32 -B/usr/lib32 test.c
% ./a.out
mmap: Invalid argument


I disassembled a.out. I think that 'movl $0x0,0x18(%esp)' is needed.
This error is occured by 'off_t offset'.

 80484ce:       83 ec 34                sub    $0x34,%esp
 80484d1:       c7 44 24 14 00 00 00    movl   $0x0,0x14(%esp)
 80484d8:       00
 80484d9:       c7 44 24 10 ff ff ff    movl   $0xffffffff,0x10(%esp)
 80484e0:       ff
 80484e1:       c7 44 24 0c 00 10 00    movl   $0x1000,0xc(%esp)
 80484e8:       00
 80484e9:       c7 44 24 08 03 00 00    movl   $0x3,0x8(%esp)
 80484f0:       00
 80484f1:       c7 44 24 04 00 10 00    movl   $0x1000,0x4(%esp)
 80484f8:       00
 80484f9:       c7 04 24 00 00 00 00    movl   $0x0,(%esp)
 8048500:       e8 43 fe ff ff          call   8048348 <mmap_at_plt>


I found this solution.

I modified machine depended header as below.
# cd /usr/include/machine
# cp /usr/src/sys/i386/include/_types.h _types32.h
# patch < _types.h.diff

-- begin -- _types.h.diff ------------------------------------------------
--- _types.h.org	2010-05-24 13:34:55.406874258 +0900
+++ _types.h	2010-05-24 13:35:33.790522354 +0900
_at__at_ -36,6 +36,10 _at__at_
  * $FreeBSD: src/sys/amd64/include/_types.h,v 1.12.2.1 2009/08/03 08:13:06 kensmith Exp $
  */
 
+#ifdef __i386__
+#include <machine/_types32.h>
+#else
+
 #ifndef _MACHINE__TYPES_H_
 #define	_MACHINE__TYPES_H_
 
_at__at_ -115,3 +119,4 _at__at_
 #endif
 
 #endif /* !_MACHINE__TYPES_H_ */
+#endif /* __i386__ */
-- end -- _types.h.diff ----------------------------------------------

In this case, 'off_t offset' is set correctly as below.

 80484d1:       c7 44 24 14 00 00 00    movl   $0x0,0x14(%esp)
 80484d8:       00
 80484d9:       c7 44 24 18 00 00 00    movl   $0x0,0x18(%esp)
 80484e0:       00
 80484e1:       c7 44 24 10 ff ff ff    movl   $0xffffffff,0x10(%esp)
 80484e8:       ff
 80484e9:       c7 44 24 0c 00 10 00    movl   $0x1000,0xc(%esp)
 80484f0:       00
 80484f1:       c7 44 24 08 03 00 00    movl   $0x3,0x8(%esp)
 80484f8:       00
 80484f9:       c7 44 24 04 00 10 00    movl   $0x1000,0x4(%esp)
 8048500:       00
 8048501:       c7 04 24 00 00 00 00    movl   $0x0,(%esp)
 8048508:       e8 3b fe ff ff          call   8048348 <mmap_at_plt>



How should we deal with this problem?

Best reards,
 Kohji Okuno