1 /* Should strace show byte or page offsets in mmap syscalls
2 * which take page offset parameters?
3 *
4 * At the time of writing, sys_mmap() converts page to byte offsets,
5 * but only for SH64! But this routine is used on i386 too - by mmap2 syscall,
6 * which uses page offsets too. As it stands now, SH64 and i386 are inconsistent.
7 *
8 * sys_old_mmap() is used for old mmap syscall, which uses byte offset -
9 * should be ok.
10 * sys_mmap64() is currently buggy (should print bogus offset, but I can't
11 * test it right now. What arch/bitness invokes sys_mmap64?)
12 *
13 * This program is intended for testing what strace actually shows. Usage:
14 * $ gcc test/mmap_offset_decode.c -o mmap_offset_decode -static
15 * $ strace ./mmap_offset_decode
16 *
17 * As of today (2011-08), on i386 strace prints page offset.
18 * Fixed 2013-02-19. Now all mmaps on all arches should show byte offsets.
19 */
20 #define _LARGEFILE_SOURCE
21 #define _LARGEFILE64_SOURCE
22 #define _FILE_OFFSET_BITS 64
23 #include <sys/mman.h>
24 #include <errno.h>
main()25 int main()
26 {
27 /* 0x1000 is meant to be page size multiplier */
28 mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
29 0x7fff0000LL * 0x1000);
30 return errno != 0;
31 }
32