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> 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
